•It. 


THE  AMERICAN 


ARTIST'S  MANUAL, 

OB 

DICTIONARY  OF  PRACTICAL  KNOWLEDGE 

IN  THE 

APPLICATION  OF  PHILOSOPHY 

TO 

THE  ARTS  AND  MANUFACTURES. 

Selected  from  the  most  complete  European  System 

WITH 

ORIGINAL  IMPROVEMENTS 

AND 

APPROPRIATE  ENGRAVINGS. 

ADAPTED  TO 

THE  USE  OF  THE  MANUFACTURERS  OF  THE  UNITED  STATES. 

BY  JAMES  CUTBUSH. 


IJV  TWO  VOLUMES— VOL.  II. 


PHILADELPHIA^ 

PUBLISHED  BY  JOHNSON  &  WARNER,  AND  R.  FISHER. 
W.  Brown,  Printer,  Church  Alley. 

1814. 


DISTRICT  OF  PENNSYLVANIA,  to  wit  : 

Be  it  remembered,  That  on  the  eighteenth  day  of  February,  in  the  thirty- 
eighth  year  of  the  independence  of  the  United  St  ates  of  America,  A.D.  1814, 
Johnson  &  Warner  and  R.  Fisher  of  the  said  district,  have  deposited  in  this 
the  Title  of  a  Book,  the  right  whereof  they  claim  as  Proprietors,  in  the 
wo'Kis  following,  to  wit : 

"  The  American  Artist's  Manual,  or  Dictionary  of  Practical  Knowledge,  in 
"  the  application  of  Philosophy  to  the  Arts  and  Manufactures.  Selected 
"  from  the  most  complete  European  systems,  with  original  improvements 
"  and  appropriate  engravings.  Adapted  to  the  use  of  the  Manufacturers 
"  of  the  United  States.    By  James  Cutbush." 

In  conformity  to  the  act  of  the  congress  of  the  United  States,  intituled,  "  An 
act  for  the  encouragement  of  learning,  by  securing  the  copies  of  Maps,  Charts, 
and  Books,  to  the  authors  and  proprietors  of  such  copies  during  the  times 
therein  mentioned  "  And  also  to  the  act,  entitled,  "  An  act  supplementary 
to  an  act,  entitled,  *  An  act  for  the  encouragement  of  learning,  by  securing  the 
copies  of  maps,  charts,  and  books,  to  the  authors  and  proprietors  of  such  copies 
during  the  times  therein  mentioned,'  and  extending  the  benefits  thereof  to  the 
arts  of  designing,  engraving,  and  etching  historical  and  other  prints." 

D.  CALDWELL, 

Clerk  of  the  District  of  Pennsylvania. 


THE 


ARTIST'S  MANUAL; 


on, 


DICTIONARY  OF  PRACTICAL  KNOWLEDGE. 


M. 


MAD 

MACHINE,  simple  and  compound.  See 
Mechanics. 

MACHINES,  principles  of  their  con- 
struction. See  Mechanics. 

MACERATION.  The  steeping  of  a 
body  in  a  cold  liquor.  It  does  not  differ 
from  Digestion,  excepting  that  the 
term  is  never  used  when  the  temperature 
of  the  mass  is  raised  beyond  that  of  the 
surrounding  air.  It  is  obvious,  that  ma- 
ceration, or  digestion  without  heat,  must 
be  used  in  all  requisite  cases  wherein  the 
fugitive  nature  of  some  of  the  component 
parts  of  the  subject  of  examination,  or 
its  disposition  to  become  changed  by  heat, 
renders  the  process  of  digestion,  assisted 
by  heat,  unfavourable  to  the  intended 
process. 

MADDER,  a  substance  very  extensive- 
ly employed  in  dyeing,  is  the  root  of  the 
rubia  tinctorum. 

Although  madder  will  grow  both  in  a 
stiff  clayey  soil,  and  in  sand,  it  succeeds 
better  in  a  moderately  rich,  soft,and  some- 
what sandy  soil :  it  is  cultivated  in  many 
of  the  provinces  of  France,  in  Alsace, 
Normandy,  and  Provence  :  the  best  of 
European  growth  is  that  which  comes 
from  Zealand. 

There  are  various  methods  of  cultivat- 
ing and  preparing  madder,  and  many  trea- 
tises have  been  written  on  the  subject: 
VOL.  II. 


MAD 

that  of  Mr.  Duhamel  may  be  consulted, 
but  more  particularly  that  of  Mr.  le  Pileur 
d'Apligny,  published  at  the  end  of  his 
Art  of  Dyeing  Threads  and  Cotton  Stuffs. 
See  also  Archives  of  Useful  Know- 
ledge. 

The  madder  prepared  for  dyeing  is  dis- 
tinguished into  different  sorts  :  that  ob- 
tained from  the  principal  roots  is  called 
crop  madder  ;  the  non  crop  is  that  which 
is  produced  from  the  stalks,  which  by  be- 
ing buried  in  the  earth  are  transformed  in- 
to roots,  and  are  called  layers :  each  of 
these  kinds  is  sub-divided  into  fine,  bale, 
bunch,  and  short,  or  mull. 

When  the  madder  roots  are  gathered, 
the  layers  are  separated  from  them,  to 
form  the  non  crop ;  and  such  of  the  fibres 
of  the  roots  as  do  not  exceed  a  certain 
degree  of  thickness  are  added,  as  are 
also  those  roots  which  are  too  thick,  and 
which  contain  a  great  deal  of  heart  or 
ligneous  part :  the  best  roots  are  about 
the  thickness  of  a  goose  quill,  or  at  most 
of  the  little  finger ;  they  are  semi-trans- 
parent, and  of  a  reddish  colour ;  they 
have  a  strong  smell,  and  the  bark  is 
smooth. 

When  the  madder  is  gathered  and 
picked,  it  must  be  dried,  in  order  to  ren- 
der it  fit  for  grinding  and  being  preserved ; 
in  warm  climates  it  is  dried  in  the  open 


MAD 


MAD 


air  ;  in  Holland,  by  means  of  stoves, 
which  sometimes  communicate  too  great 
a  degree  of  heat,  and  change  its  colour 
by  an  admixture  of  fuliginous  particles. 
Hellot  ascribes  the  superiority  of  the  mad- 
der  which  comes  from  the  Levant  to  the 
circumstance  of  its  having  been  dried  in 
the  open  air. 

After  the  root  has  been  dried,  it  must 
be  shaken  in  a  sack,  or  lightly  beaten  on  a 
wooden  hurdle,  after  which  it  must  be 
sifted  or  winnowed.  In  this  way  the  earth 
is  separated  from  it,  and  the  billon  is  re- 
moved, ii  name  by  which  the  small  roots 
and  their  bark  are  distinguished.  After 
this,  nothing  remains  but  to  reduce  it  to 
powder,  which  may  be  done  by  a  vertical 
millstone,  or  by  pestles,  or  even  by  a  com- 
mon snuff-mill. 

All  the  parts  of  the  madder  cannot  be 
powdered  with  equal  facility  ;  the  outer 
bark  and  ligneous  parts  are  more  easily 
pounded  than  the  parenchymatous  parts. 
Advantage  is  taken  of  this  circumstance 
in  order  to  separate  those  parts,  as  they 
do  not  all  give  the  same  colour ;  the  outer 
bark,  as  well  as  the  wood  within,  affords  a 
yellowish  colour,  which  spoils  the  red  we 
wish  to  obtain.  This  separation  establish- 
ed the  distinction  of  madder  into  robee, 
mirobee,  and  courte.  After  the  first  ope- 
ration of  the  mill,  the  madder  is  passed 
through  a  sieve,  with  a  cover  fitted  to  it, 
by  which  moans  what  is  called  the  short 
madder,  which  is  intended  for  tan  and 
modore  colours,  is  obtained ;  the  remain- 
der is  again  ground  and  sifted,  and  thus 
the  mi-robee  is  obtained;  and  a  third  ope- 
ration affords  the  robee.  The  madder 
thus  powdered  is  to  be  preserved  in  a  dry 
place,  well  packed  in  casks,  where  from 
its  natural  unctuosity  it  concretes  into 
lumps. 

Mr.  Beckmann  agrees  with  Mr.  Hellot 
in  opinion,  that  the  heat  of  stoves  injures 
the  colour  of  madder,  and  that  it  would 
be  better  to  dry  it  in  the  air  only,  the  effect 
of  which  might  be  promoted  by  various 
means.  He  finds  that  common  ovens, 
immediately  after  the  bread  is  taken  out, 
may  be  used  instead  of  the  Dutch  stoves, 
when  artificial  heat  is  to  be  employed.  Mr. 
d'Ambourney  has  made  some  interesting 
experiments  upon  madder ;  he  thinks, 
that  the  fresh  root  may  be  used  in  dyeing 
with  as  much  advantage  as  the  powdered. 
He  observed  that  four  pounds  of  the  fresh 
are  equal  to  one  of  the  dried,  although  in 
the  drying  seven-eighths  of  its  weight  are 
lost ;  the  expense  of  stoving,  packing,  and 
sifting  is  saved ;  and  it  is  only  necessary 
to  take  care,  that  the  roots  be  thoroughly 
washed  in  a  current  of  water  as  soon  as 
they  are  taken  out  of  the  ground  ;  they 


are  afterward  cut  into  pieces,  and  bruised 
bv  the  vertical  mill  See  Dyeing. 
"  MADDER  LAKES.  See  Colour  Mak- 
ing. 

MADDER  REDS.  See  Dyeing. 

MADDER  RED,  of  Papillon.— Some 
years  ago  a  Mr.  Papillon  set  up  a  dye- 
house  for  this  red  at  Glasgow ;  and  in 
1790  the  commissioners  for  manufactures 
in  Scotland  paid  him  a  premium,  for  com- 
municating his  process  to  the  late  Prof. 
Black,  on  condition  of  its  not  being  divulg- 
ed for  a  certain  term  of  years.  The  time 
being  expired,  it  has  been  made  public, 
and  is  as  follows  : 

Step.  I. — For  one  hundred  pounds  of 
cotton,  you  must  have  100  lb.  of  Alicant 
barilla,  20  lb.  of  pearl-ashes,  100  lb.  of 
quick  lime. 

The  barilla  is  to  be  mixed  with  soft  wa- 
ter in  a  deep  tub,  which  has  a  small  hole 
near  the  bottom  of  it,  stopped  at  first  with 
a  peg.  This  hole  is  to  be  covered  in  the 
inside  with  a  cloth  supported  by  two 
bricks,  that  the  ashes  may  be  prevented 
from  running  out  at  it,  or  stopping  it  p, 
while  the  ley  filters  through  it.  Under  this 
tub  must  be  another,  to  receive  the  ley,  ai  d 
pure  water  is  to  be  passed  repeatedly 
through  the  first  tub,  to  form  leys  of  dif- 
ferent strength,  which  are  kept  separate 
until  their  strength  is  examined.  The 
strongest  required  for  use  must  float  an 
egg,  and  is  called  the  ley  of  six  degrees  of 
the  French  hydrometer.  The  weaker  are 
afterward  brought  to  this  strength  by 
passing  them  through  fresh  barilla ;  but  a 
certain  quantity  of  the  weak,  which  is  of 
two  degrees  of  the  above  hydrometer,  is 
reserved  for  dissolving  the  oil,  the  gum, 
and  the  salt,  which  are  used  in  subsequent 
parts  of  the  process.  This  ley  of  two  de- 
grees is  called  the  weak  barilla  liquor ; 
the  other  the  strong. 

Dissolve  the  pearl  ashes  in  ten  pails,  of 
four  gallons  each,  of  soft  water,  and  the 
lime  in  fourteen  pails. 

Let  all  the  liquors  stand  till  they  be- 
come quite  clear,  and  then  mix  ten  pails 
of  each. 

Boil  the  cotton  in  this  mixture  five  hours, 
then  wash  it  in  running  water,  and  dry  it. 

Step.  It.  Bain  bis,  or  Gray  steep. — Take 
a  sufficient  quantity  (ten  pails)  of  the 
strong  barilla  water  in  a  tub,  and  mix 
with  it  two  pailf ids  of  sheep's  dung ;  then 
pour  into  it  two  quart  bottles  of  sulphuric 
acid,  one  pound  of  gum  arabic,  and  one 
pound  of  sal  ammoniac,  both  previously 
dissolved  in  a  sufficient  quantity  of  weak 
barilla  water;  and,  lastly,  twenty-five 
pounds  of  olive  oil,  previously  dissolved, 
or  well  mixed  with  two  pails  of  the  weak 
barilla  water. 


MAD 


MAG 


The  materials  of  this  steep  being  well 
mixed,  tread  down  the  cotton  into  it  until 
it  is  well  soaked ;  let  it  steep  twenty-four 
hours,  then  wring  it  hard  and  dry  it. 

Steep  it  again  twenty-four  hours,  and 
again  wring  and  dry  it. 

Steep  it  a  third  time  twenty -four  hours, 
after  which  wring  and  dry  it ;  and,  lastly, 
wash  it  well  and  dry  it. 

Step.  III.  The  white  steep — This  part  of 
the  process  is  precisely  the  same  with  the 
last  in  every  particular,  except  that  the 
sheep's  dung  is  omitted  in  the  composition 
of  the  steep. 

Step.  IV.  Gall  steep. — Boil  twenty-five 
pounds  of  bruised  galls  in  ten  pails  of  ri- 
ver water,  until  four  or  five  are  boiled 
away ;  strain  the  liquor  into  a  tub,  and 
pour  cold  water  on  the  galls  in  the  strainer 
to  wash  out  of  them  all  their  tincture. 

As  soon  as  the  liquor  is  become  milk- 
warm,  dip  your  cotton  hank  by  hank, 
handling  it  carefully  all  the  time,  and  let 
it  steep  twenty-four  hours.  Then  wring 
it  carefully  and  equally,  and  dry  it  well 
without  washing. 

Step.  V.  First  alum  Steep. — Dissolve 
twenty-five  pounds  of  Roman  alum  in 
fourteen  pails  of  warm  water,  without 
making  it  boil :  scum  the  liquor  well,  add 
two  pails  of  strong  barilla  water,  und  then 
let  it  cool  until  it  is  lukewarm. 

Dip  your  cotton,  and  handle  it  hank  by 
hank,  and  let  it  steep  twenty-four  hours  ; 
wring  it  equally,  and  dry  it  well  without 
washing. 

Step.  VI.  Secconcl  alum  Steep.— This  is 
in  every  particular  like  the  last ;  but  after 
the  cotton  is  dry,  steep  it  six  hours  in  the 
river,  and  then  wash  and  dry  it. 

Step.  VII.  Dyeing  steep — The  cotton  is 
dyed  by  about  ten  pounds  at  once,  for 
which  take  about  two  gallons  and  a  half 
of  bullock's  blood,  mix  it  in  the  copper 
with  twenty-eight  pails  of  milk-warm  wa- 
ter, stir  it  well,  add  twenty-five  pounds 
of  madder,  and  lastly  stir  all  well  toge- 
ther. Then,  having  beforehand  put  the 
cotton  on  sticks,  dip  it  into  the  liquor,  and 
move  and  turn  it  constantly  one  hour,  dur- 
ing which,  gradually  increase  the  heat  un- 
til the  liquor  begins  to  boil  at  the  end  of 
the  hour.  Then  sink  the  cotton,  and  boil 
it  gently  one  hour  longer ;  and  lastly  wash 
it  and  dry  it. 

Take  out  so  much  of  the  boiling  liquor, 
that  what  remains  may  produce  a  milk- 
warm  heat  with  the  fresh  water  with  which 
the  copper  is  again  filled  up,  and  then  pro- 
ceed to  make  up  a  dyeing  liquor,  as  above, 
for  the  next  ten  pounds  of  cotton. 

Step.  VIII.  The  fixing  steep.— Mix  equal 
parts  of  the  gray  steep  liquor  and  of  the 
white  steep  liquor,  taking  five  or  six  pails 


of  each.  Tread  down  the  cotton  into  this 
mixture,  and  let  it  steep  six  hours  ;  then 
wring  it  moderately  and  equally,  and  dry 
it  without  washing. 

Step.  IX.  Brightening  steep. — Ten  pounds 
of  white  soap  must  be  dissolved  very  care- 
fully and  completely  in  sixteen  or  eighteen 
pails  of  warm  water ;  if  any  little  bits  of 
the  soap  remain  undissolved,  they  will 
make  spots  in  the  cotton  A  dd  four  pails 
of  strong  barilla  water,  and  stir  it  well. 
Sink  the  cotton  in  this  liquor,  keeping  it 
down  with  cross  sticks,  and  cover  it  up; 
boil  it  gently  two  hours,  then  wash  it  and 
dry  it,  and  it  is  finished.  See  Dyeing. 

MAGNESIA,  or  Magnesia  Alba. 
See  Earths. 

The  artificial  carbonated  magnesia  (the 
common  magnesia,  or  magnesia  alba  of 
the  shops,)  is  prepared  by  decomposing 
the  sulphat  of  magnesia  or  Epsom  salt 
with  common  carbonat  of  potash.  To 
succeed  perfectly  in  this  preparation  se- 
veral precautions  are  requisite.  The  fol- 
lowing is  the  process  usually  given  Take 
a  pound  of  sulphat  of  magnesia  dissolved 
in  about  five  pints  of  water,  add  to  this  a 
pound  of  good  purified  pearlash,  or  pre- 
pared carbonated  potash,  dissolved  in  a 
like  quantity  of  water,  and  boil  them  for 
some  minutes.  A  copious  white  precipi- 
tate is  produced  on  the  moment  of  mix- 
ture, which  renders  the  whole  mass  ex- 
tremely thick.  Strain  it  while  hot  through 
linen  (not  paper)  and  wash  the  precipitate 
left  on  the  strainer  by  repeated  aff  usions 
of  a  very  large  quantity  of  boiling  water, 
till  it  comes  away  tasteless.  The  preci- 
pitate gently  dried  becomes  a  perfectly 
white  extremely  light  tasteless  powder, 
which  is  common  magnesia. 

A  double  decomposition  takes  place  in 
this  process,  the  sulphuric  acid  quitting 
the  sulphat  of  magnesia  to  unite  with  the 
potash,  and  the  magnesia  uniting  with  the 
carbonic  acid  of  the  alkali  employed.  The 
sulphat  of  potash  being  a  salt  of  very 
sparing  solubility  in  water,  renders  it  ne- 
cessary to  wash  the  precipitate  so  abun- 
dantly. The  drying  of  the  carbonat  of 
magnesia  is  tedious,  for  being  excessively 
light  and  spungy,  it  retains  a  large  portion 
of  water,  which  cannot  be  separated  by 
filtration.  In  the  manufacture  in  the  large 
way,  the  paste  of  magnesia  and  water  is 
spread  on  slabs  of  chalk,  which  absorb:, 
the  water  eagerly  and  much  hastens  the 
drying. 

Common  carbonat  of  magnesia  consist; 
of  carbonic  acid,  water  and  magnesia  in 
somewhat  varying  proportions.  By  being 
calcined  for  some  time  in  a  red  heat,  both, 
the  water  and  carbonic  acid  are  expelled, 
and  the  entire  loss  by  calcination  is  on  an 


MAG 


MAG 


average  about  55  per  cent.  On  the  other 
hand,  this  carbonat  when  added  to  an  acid, 
effervesces  violently,  but  only  parts  with 
its  carbonic  acid  in  the  effervescence,  and 
this  loss  is  about  34  per  cent.,  consequent- 
ly the  constituent  parts  of  100  parts  of 
the  common  carbonat  of  magnesia  will 
be,  when  dried  in  a  gentle  heat, 

Magnesia  -  -  45 
Carbonic  acid  -  34 
Water  21 

100 

The  quantity  of  alkali  commonly  used 
in  obtaining  magnesia  is  more  than  is  ne- 
cessary to  decompose  the  magnesian  sul- 
phat,  and  probably  one-fourth  or  one-fifth 
less  would  be  sufficient. 

Common  magnesia  is  scarcely  at  all  so- 
luble in  pure  water,  but  with  an  additional 
quantity  of  carbonic  acid  its  solubility  in- 
creases largely.  Hence  in  making  com- 
mon magnesia  it  is  adviseable  to  boil  the 
ingredients  on  mixture,  by  which  a  consi- 
derable quantity  of  loosely  combined  car- 
bonic acid  is  expelled,  which  otherwise 
would  unite  with  part  of  the  magnesia, 
render  it  soluble  in  water,  and  it  would  be 
carried  away  in  the  washings.  Hence  the 
more  the  alkali  employed  is  saturated  with 
carbonic  acid  (beyond  the  exact  dose  ne- 
cessary for  the  precipitated  magnesia) 
the  less  will  be  the  product  left  on  the 
filter,  unless  the  boiling  be  continued  a 
proper  time. 

For  obtaining  pure  magnesia,  or  magne- 
sia free  from  carbonic  acids,  see  Earths. 

Dr.  Bruce  has  discovered  this  earth  in 
New  Jersey. 

MAGNETIC  IRON  ORE.  See  Iron. 

MAGNET,  natural.  See  Magnet- 
ism. 

MAGNET,  artificial.  See  Magnet- 
ism. 

MAGNETISM.— The  natural  magnet 
or  loadstone,  is  a  hard  mineral  body  of  a 
dark-brown,  or  almost  black  colour,  and 
when  examined,  is  found  to  be  an  ore  of 
iron.  It  is  found  in  various  countries, 
generally  in  iron  mines,  and  of  all  sizes 
and  forms. 

This  singular  substance  was  known  to 
the  ancients ;  and  they  had  remarked 
its  peculiar  property  of  attracting  iron, 
though  it  does  not  appear  that  they  were 
acquainted  with  the  wonderful  property 
which  it  also  has,  of  turning  to  the  pole 
when  suspended,  and  left  at  liberty  to 
move  freely. 

Upon  this  remarkable  circumstance 
does  the  mariner's  compass  depend,  an 
instrument  which  gives  us  such  infinite 
advantages  over  the  ancients.  It  is  this 


which  enables  the  mariners  to  conduct 
their  vessels  through  vast  oceans  out  of 
the  sight  of  land,  in  any  given  direction  : 
and  this  directive  property  also  guides 
the  miners  in  their  subterranean  excava- 
tions, and  the  traveller  through  deserti 
otherwise  impassable. 

It  is  not  precisely  known  when  and  by 
whom  this  directive  property  of  the  mag 
net  was  discovered.  The  most  probable 
accounts  seem  to  prove,  that  it  was  known 
early  in  the  13th  century ;  and  that  the 
person  who  first  made  mariner's  com- 
passes, at  least  in  Europe,  was  a  Neapoli- 
tan of  the  name  of  Flavio,  or  John  de 
Gioja,  or  Giova,  or  Gira. 

Before  that  period,  mariners  scarcely 
ever  ventured  out  of  sight  of  land,  and  in 
the  longest  voyages  they  contented  them- 
selves with  going  round  the  coasts,  mak- 
ing by  that  means  their  journey  much 
longer.  In  the  night,  and  when  necessity 
obliged  them  to  lose  sight  of  the  shore, 
their  only  guides  were  the  heavenly 
bodies,  and  when  these  were  obscured 
by  clouds,  they  were  absolutely  without 
resource. 

While  navigation  continued  so  danger- 
ous, men  never  would  have  ventured  upon 
such  voyages  as  those  to  the  West 
Indies,  America,  and  the  South  Seas ; 
and  probably  the  existence  of  those  coun- 
tries would  have  been  still  unknown 
to  us. 

We  cannot,  therefore,  think  too  highly 
of  this  extraordinary  instrument,  which 
has  so  much  enlarged  our  stock  of  know- 
ledge, and  procured  for  us  so  many  new 
enjoyments. 

The  natural  loadstone  has  also  the 
quality  of  communicating  its  properties 
to  iron  and  steel;  and  when  pieces  of 
steel  properly  prepared  are  touched,  as 
it  is  called  by  the  loadstone,  they  are 
denominated  artifical  magnets. 

These  artificial  magnets  are  even  capa- 
ble of  being  made  more  powerful  than 
the  natural  ones,  and  as  they  can  be  made 
of  any  form,  and  are  more  convenient, 
they  are  now  universally  used  ;  so  that  the 
loadstone  or  natural  magnet  is  only  kept 
as  a  curiosity. 

All  magnets,  whether  natural  or  artifi- 
cial, are  distinguished  from  other  bodies 
by  the  following  characteristic  properties, 
which  appear  to  be  inseparable  from  their 
nature  :  so  that  no  body  can  be  called  a 
magnet,  unless  it  be  possessed  of  all  these 
properties. 

1.  A  magnet  attracts  iron. 

2.  When  a  magnet  is  placed  so  as  to 
be  at  liberty  to  move  freely  in  every  direc- 
tion, it  turns  so  that  its  ends  point  towards 
the  poles  of  the  earth,  or  very  nearly  so  : 


MAG 


MAG 


*nd  each  end  always  points  to  the  same 
pole.  This  is  called  the  polarity  of  the 
magnet :  the  ends  of  the  mag-net  are  cal- 
led poles,  and  they  are  called  north  and 
south  poles  of  the  magnet,  according  as 
they  point  to  the  north  or  south  pole  of 
the  earth.  When  a  magnet  places  itself 
in  this  direction,  it  is  said  to  traverse. 

3.  When  the  north  pole  of  one  magnet 
is  presented  to  the  south  of  another 
magnet,  these  ends  attract  each  other; 
but  if  the  south  pole  of  one  magnet  be 
presented  to  the  south  pole  of  another,  or 
the  north  pole  of  one  to  the  north  pole  of 
another,  these  ends  will  repel  each  other. 

From  these  criteria,  it  is  easy  to  deter- 
mine the  names  of  the  poles  of  a  magneti- 
cal  bar,  by  applying  it  near  a  suspended 
magnet  whose  poles  are  known. 

4.  When  a  magnet  is  situated,  so  as  to 
be  at  liberty  to  move  itself  with  sufficient 
freedom,  its  two  poles  do  not  lie  in  a 
horizontal  direction,  but  it  generally 
inclines  one  of  them  towards  the  horizon, 
and  of  course  it  elevates  the  other  pole 
above  it.  This  is  called  the  inclination,  or 
dipping  of  the  magnet. 

5.  Any  magnet  may,  by  proper  methods, 
be  made  to  impart  these  properties  to 
iron  or  steel. 

A  plane,  perpendicular  to  the  horizon, 
and  passing  through  the  poles  of  a  mag- 
net, when  standing  in  their  natural  direc- 
tion, is  called  the  magnetic  meridian  ;  and 
the  angle  which  the  magnetic  meridian 
makes,  with  the  meridian  of  the  plane 
where  the  magnet  stands,  is  called  the  de- 
clination of  the  magnet  at  that  place. 

Of  Magnetic  Attraction  and  Repulsion. 
— When  a  piece  of  iron  is  brought  within 
a  certain  distance  of  one  of  the  poles  of  a 
magnet,  it  is  attracted  by  it ;  and  if  the  iron 
be  at  liberty  to  move,  it  adheres  to  the 
magnet,  and  cannot  be  separated  without 
some  force.  It  appears  at  first  sight,  that 
the  attraction  lies  only  in  the  magnet,  but 
experiment  proves  this  attraction  to  be 
mutual;  the  iron  attracting  the  magnet 
as  much  as  the  magnet  attracts  the  iron. 
Place  the  magnet  and  the  iron  upon  two 
separate  pieces  of  cork,  or  wood,  floating 
upon  water,  at  a  little  distance  from  each 
other,  and  it  will  be  found  that  the  iron 
moves  towards  the  magnet,  as  well  as 
the  magnet  towards  the  iron  ;  if  the  iron 
be  kept  steady,  the  magnet  will  move 
towards  it. 

This  attraction  is  strongest  at  the  poles 
of  a  magnet,  and  diminishes  in  proportion 
to  the  distance  of  any  part  from  the  poles, 
so  that  in  the  middle  between  the  poles 
there  is  no  attraction.  This  may  be  easily 
perceived  by  presenting  a  piece  of  iron  to 
various  parts  of  the  surface  of  a  magnet. 


The  intensity  of  the  attractive  power 
diminishes  also,  according  to  the  dis- 
tance from  the  magnet.  If  the  magnet 
and  iron  touch  each  other,  it  requires  a 
certain  degree  of  force  to  separate  them  , 
if  the  iron  be  removed  a  little  way  from 
the  magnet,  an  attraction  will  be  plainly 
perceived,  but  not  so  powerful ;  and  by 
increasing  this  distance  the  attraction  will 
be  much  diminished. 

The  law  of  diminution  of  this  attraction 
is  not  yet  known.  Some  have  imagined 
that  it  diminished  in  proportion  to  the 
square  of  the  distance,  others  as  the  cube 
of  the  distance.  But  either  from  the  diffi- 
culty of  the  subject,  or  on  account  of  the 
experiments  having  been  made  without 
sufficient  accuracy,  the  question  remains 
yet  undecided  ;  it  is  only  known  that  the 
attractive  force  decreases  faster  than  the 
simple  ratio  of  the  distances. 

As  magnetic  attraction  takes  place  only 
between  poles  of  different  names,  and  of  dif- 
ferent magnets  ;  thatis,the  north  pole  of  one 
magnet  attracts  the  south  pole  of  another ; 
consequently  magnetic  repulsion  acts  only 
between  poles  of  the  same  name  of  differ- 
ent magnets.  Thus,  if  the  north  pole  of 
one  magnet  be  opposed  to  the  north  pole 
of  another  magnet,  or,  if  the  south  pole 
be  opposed  to  the  south  pole  of  the  other, 
then  those  magnets  will  repel  each  other, 
and  that  nearly  with  as  much  force  as  the 
poles  of  different  names  would  attract 
each  other. 

But  it  frequently  happens,  that  though 
magnets  are  placed  with  the  same  poles 
towards  each  other,  yet  they  either  attract 
each  other,  or  shew  a  perfect  indifference. 
This,  at  first,  seems  to  contradict  the 
above  mentioned  general  law ;  but  this 
difficulty  is  removed  by  the  following  con- 
siderations. 

When  a  piece  of  iron  is  brought  within 
a  certain  distance  of  a  magnet,  it  becomes, 
in  fact,  itself  a  magnet,  having  the  polar- 
ity, the  attractive,  and  repulsive  properties 
for  other  iron,  &c. ;  that  part  of  it  which 
is  nearest  to  the  south  pole  of  the  mag- 
net, becoming  a  north  pole,  and  the  oppo 
site  part  a  south  pole,  or  vice  versa,  ac 
cording  to  the  end  of  the  magnet  pre- 
sented. 

Soft  iron,  when  placed  within  the  in- 
fluence  of  a  magnet,  easily  acquires  these 
properties ;  but  they  last  only  while  the 
iron  remains  in  that  situation,  and  when 
it  is  removed,  its  magnetism  vanishes  im- 
mediately. But  with  iron  containing  car- 
bon, and  particularly  with  steel,  the  case 
is  very  different ;  and  the  harder  the  iron 
or  the  steel  is,  the  more  permanent  is  the 
magnetism  which  it  acquires  from  the  in- 
fluence of  a  magnet ;  but  it  will  be  in  the 


MAG 


MAG 


same  proportion  more  difficult  to  render 
it  magnetic. 

If  a  piece  of  soft  iron,  and  a  piece  of 
hard  steel,  both  of  the  same  shape  and  size, 
be  brought  within  the  influence  of  a  mag- 
net at  the  same  distance,  it  will  be  found 
that  the  iron  is  attracted  more  forcibly, 
and  appears  more  powerfully  magnetic 
than  the  steel ;  but  if  the  magnet  be  re- 
moved,  the  soft  iron  will  instantly  lose  its 
acquired  properties,  whereas  the  hard 
steel  will  preserve  them  for  a  long  time, 
having  become  an  artificial  magnet. 

It  appears  from  these  facts,  that  there 
is  no  magnetic  attraction  but  between  the 
contrary  poles  of  magnets  :  for  the  iron 
which  is  presented  to  the  magnet,  must 
itself  become  a  magnet,  before  it  is  capa- 
ble of  being  attracted.  It  appears,  also, 
why  a  magnet  has  a  greater  attraction  for 
soft  than  for  hard  iron,  and  still  more  for 
hard  steel;  the  steel  not  becoming  so 
easily  magnetical  as  the  iron,  by  present- 
ing it  to  a  magnet.  This  also  explains 
why  only  poles  of  the  same  name  repel 
each  other :  for,  when  the  north  pole  of 
one  magnet  does  not  seem  to  attract  or  re- 
pel, or  it  actually  attracts  what  was  called 
the  north  pole  of  the  other  magnet,  the 
fact  is,  either  that  the  two  north,  or  the 
two  south  poles  have  destroyed  each 
other ;  or,  that  the  superior  force  of  one 
of  the  magnets  has  actually  changed  the 
poles  of  the  weaker  magnet,  as  is  beyond 
a  doubt  proved  by  experiment. 

Neither  the  magnetic  attraction  nor  re- 
pulsion is  in  the  least  diminished,  or  at  all 
affected  by  the  interposition  of  any  sort 
of  bodies,  except  iron,  or  such  bodies  as 
contain  iron. 

The  properties  of  the  magnet  are  not 
affected  either  by  the  presence  or  by  the 
absence  of  air.  Heat  weakens  the  power 
of  a  magnet,  and  subsequent  cooling  re- 
stores it,  but  not  quite  to  its  former  de- 
gree A  white  heat  destroys  it  entirely, 
or  very  nearly  so  :  and,  hence  it  appears, 
that  the  powers  of  magnets  must  be  vary- 
ing continually.  Cavallo  observes, that 
iron  in  a  ftill  red  heat,  or  white  heat,  is  not 
attracted  by  the  magnet ;  but  the  attrac- 
tion commences  as  soon  as  the  redness 
begins  to  disappear. 

The  attractive  power  of  a  magnet  may 
be  considerably  improved  by  hanging  a 
weight  to  it,  which  may  be  gradually  in- 
creased ;  and  also  by  keeping  it  in  a  pro- 
per situation,  viz.  with  its  north  pole  to- 
wards the  north,  and  its  south  pole,  con- 
-equently,  towards  the  south.  On  the 
contrary,  this  power  is  diminished  by  an 
improper  situation,  and  by  keeping  too 
small  a  piece  of  iron,  or  no  iron  at  all, 
Appended  to  it. 


In  these  northern  parts  of  the  world, 
the  north  pole  of  a  magnet  has  more  pow- 
er than  its  south  pole  ;  whereas,  the  con- 
trary effect  has  been  said  to  take  place 
in  the  southern  parts. 

Most  probably  the  magnet  attracts  iron 
only  ;  but  when  it  is  considered  how  uni- 
versally iron  is  dispersed  throughout  na- 
ture, it  is  evident  that  a  vast  number  of 
bodies  must  on  that  account  be  attracted 
by  the  magnet  more  or  less  forcibly,  in 
proportion  to  the  quantity  and  quality  of 
the  iron  they  contain.  Indeed,  it  is  won- 
derful to  observe,  what  a  small  portion  of 
iron  will  render  a  body  subject  to  the  in- 
fluence of  the  magnet.  However,  though 
it  must  be  acknowledged  that  every  body 
which  contains  iron  is  in  some  measure 
attracted  by  the  magnet,  yet  it  does  not 
follow  that  no  other  body  can  be  attracted 
by  it.  A  great  many  substances  are  in  a 
very  slight  degree  attracted,  which  seem 
to  contain  either  no  iron  at  all,  or  an  ex- 
ceedingly small  quantity  of  it,  extremely 
diffused  and  oxydated. 

To  discover  this  small  degree  of  attrac- 
tion, the  substances  should  be  placed 
upon  a  piece  of  paper,  or  a  thin  shaving 
of  cork,  which  should  be  put  to  float  upon 
water,  and  then  the  magnet  should  be 
gently  approached  sideways,  to  within 
one-tenth  of  an  inch  distance  from  the 
substance  under  trial.  The  following  sub- 
stances will  in  this  manner,  be  found  to  be 
in  some  measure,  affected  by  the  magnet, 
viz.  most  metallic  ores,  especially  after 
having  been  exposed  to  a  fire.  Zinc,  bis- 
muth, and  particularly  cobalt,  are  gene- 
rally attracted.  The  calcareous  is  the 
least  attractable  of  the  earths,  and  the  si- 
liceous is  the  most  frequently  attracted. 
The  ruby,  the  chrysolite,  the  tourmalin, 
and  the  opal  are  attracted.  The  emerald, 
and  particularly  the  garnet,  are  not  only- 
attracted,  but  frequently  acquire  perma- 
nent magnetism.  Amber,  and  many  other 
combustible  minerals  are  attracted,  espe- 
cially after  combustion.  The  ashes  of 
most  animal  and  vegetable  substances,  are 
attracted ;  also  soot,  and  the  dust  which 
floats  in  the  atmosphere,  are  often  attract- 
ed by  the  magnet. 

Cavallo  discovered,  that  if  most  speci- 
mens of  brass  which  shew  no  attraction 
towards  the  magnet,  be  hammered,  they 
will,  in  that  hardened  state  (produced  by 
the  hammering)  be  attracted.  The  same 
piece  of  brass  will  no  longer  be  attracted, 
after  being  softened  in  the  fire :  a  second 
hammering  will  again  render  it  attracta- 
ble, and  so  on  repeatedly.  Most  of  the 
native  grains  of  platina  have  the  same 
property. 

In  the  examination  of  the  magnetism  of 


MAG 


MAG 


various  bodies,  it  may  be  of  importance  to 
knovr  the  degrees  of  magnetism,  as  disco- 
verable by  experiment,  which  are  the  fol- 
lowing :  the  weakest  is,  when  a  body  float- 
ing on  water  slowly  follows  a  strong  mag- 
net, held  almost  touching  it ;  the  next  is, 
when  a  magnet  can  repel  as  well  as  at- 
tract the  body ;  a  still  stronger  degree  is, 
when  the  body  conforms  its  position  to 
that  of  the  magnet  held  over  it;  the 
fourth  is,  when  the  body,  left  to  itself,  as- 
sumes a  particular  position,  and  returns 
to  it  when  disturbed ;  the  fifth  is,  when 
the  body,  taken  out  of  the  water,  and 
brought  near  a  magnet,  causes  it  to  devi- 
ate From  the  magnetic  meridian.  All 
stronger  degrees  of  magnetism  may  be  ob- 
served by  less  delicate  methods. 

Of  the  Polarity  of  the  Magnet. — Every 
magnet  has  a  south  and  a  north  pole, 
which  are  at  opposite  ends  ;  and  a  line 
drawn  from  one  to  the  other,  passes 
through  the  centre  of  the  magnet.  Here  it 
must  not  be  understood,  that  the  polarity 
of  a  magnet  resides  only  in  two  points  ol 
its  surface,  for  in  reality,  it  is  the  one  half 
of  the  magnet  that  is  possessed  of  one 
kind  of  polarity,  and  the  other  half  of  the 
other  kind  of  polarity  :  the  poles  then,  are 
those  points  in  which  that  power  is  the 
strongest. 

The  line  drawn  from  one  pole  to  the 
other,  is  called  the  axis  of  the  magnet, 
and  a  line  formed  all  round  the  surface  of 
the  magnet,  by  a  plane  which  divides  the 
axis  into  two  equal  parts,  and  is  perpen- 
dicular to  it,  is  called  the  equator  of  the 
magnet. 

It  isyhe  polarity  of  the  magnet  that  ren- 
ders it  so  useful  to  navigators.  When  a 
magnet  is  kept  suspended  freely,  so  that 
it  may  turn  north  and  south,  the  pilot,  by 
looking  at  the  position  of  it,  can  steer  his 
course  in  any  required  direction.  Thus, 
if  a  vessel  is  steered  towards  a  certain 
place  which  lies  exactly  westward  of  that 
from  which  it  set  out,  the  navigator  must 
direct  it  so,  that  its  course  may  be  always 
at  right  angles,  with  the  direction  of  the 
magnetic  needle  of  his  compass,  keeping 
the  north  end  of  the  magnet  on  the  right 
hand  side,  and  of  course,  the  south  end  on 
the  left  hand  side  of  the  vessel ;  for  as  the 
needle  points  nortli  and  south,  and  the  di- 
rection is  east  and  west,  the  intended 
course  of  the  vessel  is  exactly  perpendicu- 
lar to  the  position  of  the  magnet  A  little 
reflection  will  shew  how  the  vessel  may 
be  steered  in  any  other  direction. 

An  artificial  magnet  fitted  up  in  a  pro- 
per box,  for  the  purpose  of  guiding  the 
direction  of  a  traveller,  is  called  a  magne- 
tic needle,  and  the  whole  together,  is  call- 
/    ed  the  mariner's  compass. 


Although  the  north  pole  of  the  magnet 
in  every  part  of  the  world,  when  suspend- 
ed, points  towards  the  northern  parts,  and 
the  south  pole  towards  the  southern  parts, 
yet  its  ends  seldom  point  exactly  towards 
the  poles  of  the  earth.  The  angle  in 
which  it  deviates  from  due  north  and 
south,  is  called  the  angle  of  declination,  or 
the  declination  of  the  magnetic  needle,  or 
the  variation  of  the  compass ;  and  this  de- 
clination is  said  to  be  east  or  west,  accord- 
ing as  the  north  pole  of  the  needle  is  east- 
ward or  westward  of  the  astronomical 
meridian  of  the  place. 

This  deviation  from  the  meridian  is  not 
the  same  in  all  parts  of  the  world,  but  is 
different  in  different  places,  and  it  is  even 
continually  varying  in  the  same  place. 
For  instance,  this  declination  is  not  the 
same  in  I^ondon  as  at  Paris,  or  as  in  In- 
dia ;  and  the  declination  in  London,  or  in 
any  other  place,  is  not  the  same  at  this 
time  as  it  was  some  years  ago.  This  de- 
clination from  the  meridian  is  so  variable, 
that  it  may  be  observed  to  change,  even  in 
one  or  two  hours  time ;  and  this  is  not  ow- 
ing to  the  construction  of  the  magnetic 
needle,  for  in  the  same  place,  and  at  the 
same  time,  all  true  magnetic  needles 
point  the  same  way. 

The  declination  from  the  meridian,  and 
the  variation  of  this,  in  different  parts  of 
the  world,  is  very  uncertain,  and  cannot 
be  foretold  :  actual  trial  is  the  only  meth- 
od of  ascertaining  it.  This  circumstance 
forms  a  great  impediment  to  the  improve- 
ment of  navigation.  It  is  true,  that  great 
pains  have  been  taken  by  navigators  and 
other  observers,  to  ascertain  the  declina- 
tion in  various  parts  of  the  world,  and 
such  declinations  have  been  marked  in 
maps,  charts,  books,  &c  ;  but  still,  on  ac- 
count of  the  constant  change  to  which 
this  variation  is  liable,  these  can  only  serve 
for  a  few  years;  nor  has  the  law  of  this 
variation  or  fluctuation  been  yet  discover- 
ed, though  various  hypotheses  have  been 
formed  for  that  purpose.  When  the  va- 
riation was  first  observed,  the  north  pole 
of  the  magnetic  needle  declined  eastward 
of  the  meridian  of  London  ;  but  it  has  since 
that  time  been  changing  continually  to- 
wards the  west ;  so  that  in  the  year  1637 
the  magnetic  needle  pointed  due  nortli 
and  south.  At  present,  it  declines  about 
2-H°  westward,  and  it  seems  to  be  still 
advancing  towards  the  west. 

Before  volcanic  eruptions  and  earth- 
quakes, the  magnetic  needle  is  often  sub- 
ject to  very  extraordinary  movements. 

It  is  also  agitated  before  and  after  the 
appearance  of  the  aurora  borealis. 

Of  the  Magnetic  Inclination,  or  Dip  of 
the  Needle. — If  a  needle  which  is  accu- 


MAG 


MAG 


rately  balanced,  and  suspended  so  as  to 
turn  freely  in  a  verticle  plane,  be  rendered 
magnetical,  the  north  pole  will  Ibe  de- 
pressed, and  the  south  pole  elevated  above 
the  horizon :  this  property  is  called  the 
inclination,  or  dip  of  the  needle,  and  was  dis- 
covered by  Robert  Norman,  about  the 
year  1576. 

To  illustrate  this,  take  a  globular  mag- 
net, or,  what  is  more  easily  procured,  an 
oblong  one,  and  place  it  horizontally  upon 
a  table  :  then  take  another  small  oblong 
magnet,  and  suspend  it  by  means  of  a 
thread,  tied  to  its  middle]  or  centre  of 
gravity,  so  that  it  will  remain  in  an  hori- 
zontal position,  when  not  disturbed  by  the 
vicinity  of  iron,  or  other  magnets  Now 
bring  this  small  magnet  held  by  the 
thread,  just  over  the  middle  of  the  large 
magnet,  and  within  two  or  three  inches  of 
it ;  the  former  will  turn  its  south  pole  to- 
wards the  north  pole  of  the  large  magnet, 
and  its  north  pole  towards  the  south  pole 
of  the  large  one. 

It  will  be  also  noticed,  that  the  small 
magnet,  whilst  kept  just  over  the  middle 
of  the  large  one,  will  remain  parallel  to 
it ;  for  since  the  poles  of  the  small  mag- 
net are  equally  distant  from  the  contrary 
poles  of  the  large  magnet,  they  are 
equally  attracted  ;  but  if  the  small  mag- 
net be  brought  a  little  nearer  to  one  end 
than  to  the  other  of  the  large  magnet, 
then  one  of  its  poles,  namely,  that  which 
is  nearest  to  the  contrary  pole  of  the  large 
magnet,  will  be  inclined  downwards,  and 
of  course,  the  other  pole  will  be  elevated 
above  the  horizon.  This  inclination,  it  is 
evident,  must  increase  according  as  the 
small  magnet  is  placed  nearer  to  one  of 
the  poles  of  the  large  one,  because  the 
attraction  of  the  nearest  pole  will  have 
more  power  upon  it.  If  the  small  magnet 
be  brought  just  opposite  to  one  of  the 
poles  of  the  large  one,  it  will  turn  the 
contrary  pole  towards  it,  and  will  place 
itself  in  the  same  straight  line  with  the 
axis  of  the  large  magnet. 

This  simple  experiment  will  enable  the 
reader  to  comprehend  easily  the  pheno- 
mena of  the  magnetic  inclination,  or  of 
the  dipping  needle,  upon  the  surface  of 
the  earth  ;  for  it  is  only  necessary  to 
imagine  that  the  earth  is  a  large  magnet 
(as  in  fact  it  appears  to  be),  and  that  any 
magnet,  or  magnetic  needle  commonly 
used,  is  the  small  magnet  employed  in 
the  above-mentioned  experiment  ;  for, 
supposing  that  the  north  pole  of  the  earth 
is  possessed  of  a  south  magnetic  polarity, 
and  that  the  opposite  pole  is  possessed 
of  a  north  magnetic  polarity,  it  appears 
evident,  and  it  is  confirmed  by  actual  ex- 
perience, that  when  a  magnet,  or  mag- 1 


netic  needle,  properly  shaped  and  sus. 
pended,  is  kept  near  the  equator  of  the 
earth,  or,  more  properly  speaking,  near 
the  magnetic  equator  of  the  earth  (since 
neither  the  magnetic  equator,  nor  the 
magnetic  poles  of  the  earth,  coincide  with 
its  real  equator  and  poles),  it  must  remain 
in  an  horizontal  situation  :  if  the  magnet 
be  removed  nearer  to  one  of  the  mag- 
netic poles  of  the  earth,  it  must  incline  to 
one  of  its  extremities,  namely,  that  which 
is  possessed  of  the  contrary  polarity  ; 
and  this  inclination  must  increase  in 
proportion  as  the  needle  recedes  from 
the  magnetic  equator  of  the  earth.  Lastly, 
when  the  needle  is  brought  exactly  over 
one  of  the  magnetic  poles  of  the  earth,  it 
must  stand  perpendicular  to  the  horizon 
of  that  place. 

A  magnetical  needle  constructed  for 
the  purpose  of  shewing  this  property,  is 
called  a  dipping  needle,  and  its  direction 
in  any  place  is  called  the  magnetical  line. 
When  it  was  said  above,  that  the  north 
pole  of  the  earth  possessed  south  polarity, 
it  was  only  meant  that  it  had  a  polarity- 
contrary  to  that  end  of  the  magnetic 
needle  which  is  directed  towards  it. 

If  the  geographical  poles  of  the  earth 
(that  is,  the  ends  of  its  axis),  coincided 
with  its  magnetic  poles ;  or  even  if  the 
magnetic  poles  were  constantly  at  the 
same  distance  from  them,  the  inclination 
of  the  needle,  as  well  as  its  declination, 
would  always  be  the  same  ;  and  hence, 
by  observing  the  direction  of  the  magnetic 
needle  in  any  particular  place,  the  lati- 
tude and  longitude  of  that  place  might  be 
ascertained ;  but  this  is  not  the  case,  for 
the  magnetic  poles  of  the  earth  do  not 
coincide  with  its  real  poles,  and  they  are 
also  constantly  shifting  their  situations  j 
hence  the  magnetic  needle  changes  con- 
tinually and  irregularly,  not  only  in  its 
horizontal  direction,  but  likewise  in  its 
inclination,  according  as  it  is  removed 
from  one  place  to  another,  and  also  while 
it  remains  in  the  very  same  place. 

This  change  of  the  dip  in  the  same 
place,  however,  is  very  small.  In  Lon- 
don, about  1576,  the  north  pole  of  the 
dipping  needle  stood  71°  50"  below  the 
horizon  ;  and  in  1775,  it  stood  at  72°  3' 
the  whole  change  of  inclination,  during  so 
many  years,  amounting  to  less  than  a 
quarter  of  a  degree. 

The  Magnetic  Touch,  or  communicated 
Magnetism. — It  has  been  already  shewn, 
that  when  a  piece  of  iron  comes  suffi- 
ciently near  to  a  magnet,  it  becomes  itself 
a  magnet;  and  that  this  magnetism  is 
more  easily  communicated  to,  but,  at  the 
same  time,  more  easily  lost,  by  soft  iron 
than  by  steel. 


MAC 


MAG 


There  are  various  methods  of  giving 
the  magnetic  property  to  steel  or  iron, 
but  for  all  these  a  magnet  is  necessary. 
Id  some  cases,  however,  it  appears  to  be 
acquired  without  the  use  of  another  mag- 
net ;  but  this  is  founded  on  a  mistake. 

If  you  take  a  bar  of  iron  three  or  four 
feet  long,  and  hold  it  in  a  vertical  position, 
you  will  find  that  the  bar  is  magnetic,  and 
will  act  upon  another  magnet ;  the  lower 
extremity  of  the  bar  attracting  the  south 
pole,  and  repelling  the  north  pole.  If 
you  invert  the  bar,  the  polarity  will  be 
instantly  reversed ;  the  extremity  which 
is  now  lowest,  will  be  found  to  be  a  north 
pole,  and  the  other  extremity  will  be  a 
south  pole. 

This  is  easily  explained,  when  it  is  con- 
sidered that  the  earth  is  itself  a  great  mag- 
net, and  that  the  bar  is  placed  by  hold- 
ing it  nearly  vertical,  in  the  magnetical 
line,  viz.  in  the  direction  of  the  dipping 
needle. 

A  bar  of  hard  iron,  or  steel,  will  not 
answer  for  the  above  experiment,  the 
magnetism  of  the  earth  not  being  suffi- 
cient to  magnetise  it. 

Bars  of  iron  that  have  stood  in  a  per- 
pendicular position,  are  generally  found 
to  be  magnetical,  as  fire  irons,  bars  of 
windows,  &c. 

If  a  long  piece  of  hard  iron  be  made 
red  hot,  and  then  left  to  cool  in  the  direc- 
tion of  the  magnetical  line,  it  becomes 
magnetical. 

Striking  an  iron  bar  with  a  hammer,  or 
rubbing  it  with  a  file,  while  held  in  this 
direction,  likewise  renders  it  magnetical. 
An  electric  shock  produces  the  same 
effect;  and  lightning  often  renders  iron 
magnetic. 

A  magnet  cannot  communicate  a  degree 
of  magnetism  stronger  than  that  which 
itself  possesses,  but  two  or  more  magnets, 
joined  together,  may  communicate  a  grea- 
ter power  to  a  piece  of  steel,  than  either 
of  them  possesses  singly:  hence  we  have 
a  method  of  constructing  very  powerful 
magnets,  by  first  constructing  several 
weak  magnets,  and  then  joining  them 
together,  to  form  a  compound  magnet, 
and  to  act  more  powerfully  upon  a  piece 
of  steel. 

To  give  a  detail  of  the  various  proces- 
ses which  have  been  suggested  for  the 
touching,  or  communicating  the  proper- 
ties of  the  magnet  to  iron  or  steel,  would 
alone  fill  a  volume ;  we  shall  therefore  only 
give  an  account  of  two  general  and  good 
methods,  which  will  be  found  adequate 
to  every  common  purpose. 

1.  Place  two  magnetic  bars,  A  B  fig.  1, 
in  a  line  with  the  north,  or  marked  end 
of  one,  opposed  to  the  south,  or  unmarked 

VOL.  II. 


end  of  the  other,  but  at  such  a  distance 
from  each  other,  that  the  magnet  to  be 
touched,  may  rest  with  its  marked  end  on 
the  unmarked  end  of  A,  and  its  unmarked 
end  on  the  marked  end  of  B ;  then  apply 
the  north  end  of  the  magnet  D,  and  the 
south  end  of  E  to  the  middle  of  the  bar  C, 
the  opposite  ends  being  elevated  as  in 
the  figure ;  draw  D  and  E  asunder  along 
the  bar  C,  one  towards  A,  the  other 
towards  B,  preserving  the  same  eleva- 
tion ;  remove  I)  and  C  a  foot  or  two  from 
the  bar  when  they  are  off"  the  ends,  then 
bring  the  north  and  south  poles  of  these 
magnets  together,  and  apply  them  again 
to  the  middle  of  the  bar  C  as  before ; 
repeat  the  same  process  five  or  six  times, 
then  turn  the  bar,  and  touch  the  opposite 
surface  in  the  same  manner,  and  after- 
wards the  two  remaining  surfaces;  by 
this  means  the  bar  will  acquire  a  strong 
fixed  magnetism. 


2.  Place  the  two  bars  which  are  to  be 
touched  parallel  to  each  other,  and  then 
unite  the  ends  by  two  pieces  of  soft  iron, 
called  supporters,  in  order  to  preserve, 
during  the  operation,  the  circulation  of 
the  magnetic  matter ;  the  bars  are  to  be 
placed  so  that  the  marked  end  D  fig.  .2, 


may  be  opposite  the  unmarked  end  B  ; 
then  place  the  two  attracting  poles  G  and 
I  on  the  middle  of  one  of  the  bars  to  be 
touched,  raising  the  ends,  so  that  the 
bars  may  form  an  obtuse  angle  of  100  or 
120  degrees ;  the  ends  ii  ajidl  of  the  bars 


MAG 


MAG 


are  to  be  separated  two  or  three  tenths  df  j 
an  inch  from  each  other     Keeping-  the  j 
bars  in  this  position,  move  them  slowly  i 
over  the  bar  A  B,  from  one  end  to  the  ; 
other,  going-  from  end  to  end  about  fifteen 
times.     Huving  done  this,  change  the 
poles  of  the  bars  (i  e.  the  marked  end  of 
one  is  always  to  be  against  the  unmarked 
end  of  the  other),  and  repeat  the  same 
operation  on  the  bar  C  D,  and  then  on  the 
opposite  faces  of  the  bars.    The  touch 
thus  communicated  may  be  further  in- 
creased, by  rubbing  the  different  faces  of 
the  bars  with  sets  of  magnetic  bars,  dispos- 
ed as  in  fig.  3. 


In  these  operations  all  the  pieces  should 
be  well  polished,  the  sides  and  ends  made 
quite  flat,  and  the  angles  quite  square. 

A  magnet,  bent  so  that  the  two  ends 
almost  meet,  is  called  a  horse-shoe  mag- 
net. To  render  it  magnetic,  place  a  pair 
of  magnetic  bars  against  the  ends  of  the 
horse-shoe,  with  the  south  end  of  the  bar 
against  that  of  the  horse-shoe  which  is 
intended  to  be  the  north,  and  the  north 
end  of  the  bar  to  that  which  is  to  be  south  : 
the  contact,  or  lifter  of  soft  iron  to  be 
placed  at  the  other  end  of  the  bars.  Also 
rub  the  surfaces  of  the  horse-shoe  with  a 
pair  of  bars  placed  in  the  form  of  a  com- 
pass, or  with  another  horse-shoe  magnet, 
turning  the  pole  properly  to  the  poles  of 
the  horse-shoe  magnet ;  being  careful  that 
these  bars  never  touch  the  ends  of  the 
straight  bars.  If  the  bars  are  separated 
suddenly  from  the  horse-shoe  magnet,  its 
force  will  be  considerably  diminished  :  to 
prevent  this,  slip  on  the  lifter,  or  support, 
to  the  end  of  the  horse-shoe  magnet,  but 
in  such  a  manner,  however,  that  it  may 
not  touch  the  bars  ;  the  bars  may  then 
be  taken  away,  and  the  support  slid  to 
its  place. 

Magnetism  is  best  communicated  to 
compass-needles  by  the  two  following- 
methods  : 

Procure  a  pair  of  magnetic  bars,  not 
less  than  six  inches  in  length.  Fasten 
the  needle  down  on  a  board,  and  with  a 
magnet  in  each  hand,  draw  them  from  the 
centre  upon  the  needle  outwards ;  then 
raise  the  bars  to  a  considerable  distance 
from  the  needle,  and  bring  them  perpen- 
dicularly down  upon  the  centre,  and  draw 
them  over  again.   This  operation  repeat- 


ed about  twenty  times  will  magnetize 
the  needle,  and  its  ends  will  point  to  the 
poles  contrary  to  those  that  touched 
them. 

2  Over  one  end  of  a  combined  horse- 
shoe magnet,  of  at  least  two  in  number,  and 
six  inches  in  length,  draw  from  its  centre 
that  half  of  the  needle  which  is  to  have 
the  contrary  pole  to  the  end  of  the  mag- 
net; raise  the  needle  to  a  considerable 
distance,  and  draw  it  over  the  magnet 
again  ;  this  repeated  about  twenty  times 
at  least,  and  the  same  for  the  other  half, 
will  sufficiently  communicate  the  power. 
In  communicating  magnetism,  it  is  best 
to  use  weak  magnets  first,  and  those  that 
are  stronger  afterwards ;  but  you  must 
be  very  careful  not  to  use  weak  after 
strong  magnets. 

A  magnet  loses  nothing  of  its  own  pow- 
er by  communicating  to  other  substances, 
but  is  rather  improved  thereby. 

Every  kind  of  violent  percussion  weak- 
ens  the  power  of  a  magnet.  A  strong 
magnet  has  been  entirely  deprived  of  its 
virtue,  by  receiving  several  smart  strokes 
of  a  hammer  ;  indeed,  whatever  deranges 
or  disturbs  the  internal  pores  of  a  magnet, 
will  injure  its  magnetic  force. 

Fill  a  small  dry  glass  tube  with  iron 
filings,  press  them  in  rather  close,  and 
then  touch  the  tube  as  if  it  were  a  steel 
bar,  and  the  tube  will  attract  a  light 
needle  ;  shake  the  tube,  so  that  the  situa- 
tion of  the  filings  may  be  disturbed,  and 
the  magnt  tic  virtue  will  vanish. 

As  both  magnetic  poles  together  attract 
a  much  greater  power  than  a  single  one., 
and  as  the  two  poles  of  a  magnet  are  ge- 
nerally in  opposite  parts  of  its  surface,  in 
which  situation  it  is  almost  impossible  to 
adapt  the  same  piece  of  iron  to  both  at  the: 
same  time :  two  soft  pieces  of  iron  are  ap- 
plied to  the  poles  of  a  loadstone,  so  as  to 
project  on  one  side  of  the  magnet;  these 
pieces  being  rendered  magnetic,  another 
piece  of  iron  can  be  conveniently  adapted 
to  these  projections,  so  as  to  let  both 
poles  act  at  the  same  time:  The  magnet 
in  this  case,  is  said  to  be  armed :  the  pie  • 
ces  of  iron  are  called  the  armature ;  the 
piece  of  iron  that  connects  the  poles,  is 
termed  the  lifter. 

To  avoid  the  expence  and  trouble  of  the 
armature,  artificial  magnets  have  been 
made  in  the  shape  of  a  horse-shoe. 

Magnets  should  never  be  left  with  two 
north,  or  two  south  poles  together ;  for. 
when  they  are  thus  placed,  they  diminish 
and  destroy  each  other's  power.  Magne^ 
tic  bars  should  therefore  be  always  left, 
with  the  opposite  poles  laid  against  each 
other,  or  by  connecting  their  opposite 
poles  by  a  bar  of  iron.   The  power  of  a 


MAG 


MAG 


magnet  is  increased  by  letting"  a  piece  of 
iron  remain  attached  to  one  or  both  of  its 
poles.  A  single  magnet  should  therefore 
be  always  thus  left. 

The  difference  of  steel  in  receiving 
magnetism  is  very  great,  as  is  easily  prov- 
ed by  touching  in  the  same  manner  and 
with  the  same  bars,  two  pieces  of  steel  of 
equal  size,  but  of  different  kinds.  With 
some  sorts  of  steel,  a  few  strokes  are  suf- 
ficient to  impart  to  them  all  the  power 
they  are  capable  of  receiving ;  other  sorts 
require  a  longer  operation  ;  sometimes  it 
is  impossible  to  give  them  more  than  a 
small  degree  of  magnetism. 

A  piece  of  spring-tempered  steel  will 
not  retain  as  much  magnetism  as  hard 
steel ;  soft  steel  still  less,  and  iron  retains 
scarce  any.  Iron  when  oxydated,  loses  its 
magnetism,  and  cannot  be  made  magneti- 
cal ;  but  when  revived,  it  again  acquires 
the  magnetic  virtue 

The  mariner's  compass,  or  compass  ge- 
nerally used  on  board  of  ships,  consists  of 
three  parts  ;  the  box,  the  card  or  fly,  and 
the  needle.  The  box,  which  contains  the 
card  with  the  needle,  is  made  of  a  circu- 
lar form,  and  either  of  wood,  brass  or  cop- 
per. It  is  suspended  within  a  square 
wooden  box,  by  means  of  two  concentric 
circles  called  gimbalds,  so  fixed  by  cross 
axles  to  the  two  boxes,  that  the  inner  one, 
or  compass-box,  shall  retain  a  horizontal 
position  in  all  motions  of  the  ship,  whilst 
the  outer,  or  square  box,  is  fixed  with  re- 
spect to  the  ship.  The  compass-box  is 
covered  with  a  pane  of  glass,  in  order  that 
the  motion  of  the  card  may  not  be  disturb- 
ed by  the  wind.  What  is  called  the  card, 
is  a  circular  piece  of  paper,  which  is  fast- 
ened upon  the  needle,  and  moves  with  it 
Sometimes  there  is  a  slender  rim  of  brass, 
which  is  fastened  to  the  extremities  of  the 
needle,  and  serves  to  keep  the  card 
stretched.  The  outer  edge  of  this  card  is 
divided  into  360  equal  parts  or  degrees, 
and  within  the  circle  of  those  divisions  it 
is  again  divided  into  32  equal  parts  or 
arcs,  which  are  called  the  points  of  the 
compass,  or  rhumbs,  each  of  which  is  oft- 
«n  subdivided  into  quarters.  The  initial 
letters  N,  N,  E,  &c.  are  annexed  to  those 
rhumbs,  to  denote  the  north,  north-east, 
&c.  The  middlemost  part  of  the  card  is 
generally  painted  with  a  sort  of  a  star, 
whose  rays  terminate  in  the  above-men- 
tioned divisions. 

The  magnetic  needle  is  a  slender  bar  of 
hardened  steel,  having  a  pretty  large  hole 
in  the  middle,  to  which  a  conical  piece  of 
agate  is  adapted,  by  means  of  a  brass 
plate  into  which  the  agate  case  is  fasten- 
ed. The  apex  of  this  hollow  cap  rests 
upon  the  point  of  a  pin  which  is  fixed  in 


the  «entre  of  the  box,  and  upon  which  the 
needle,  being  properly  balanced,  turns 
very  nimbly.  For  commou  purposes, 
those  needles  have  a  conical  perforation 
made  in  the  steel  itself,  or  in  a  piece  of 
brass  which  is  fastened  in  the  middle  of 
the  needle. 

It  must  be  observed,  that  the  needle, 
which  is  balanced  before  it  is  magnetized, 
will  lose  its  balance  by  being  magnetized, 
on  account  of  the  dipping ;  therefore,  a 
small  weight,  or  moveable  piece  of  brass, 
is  placed  on  one  side  of  the  needle,  by  the 
shifting  of  which,  either  nearer  to,  or  far- 
ther from  the  centre,  the  needle  will  al- 
ways be  balanced. 

The  azimuth  compass,  is  nothing  more 
than  the  above-mentioned  compass,  to 
which  two  sights  are  adapted,  through 
which  the  sun  is  to  be  seen,  in  order  to 
find  its  azimuth,  and  from  thence  to  as- 
certain the  declination  of  the  magnetic 
needle  at  the  place  of  observation  :  in  one 
of  these  is  an  oblong  aperture,  with  a  per- 
pendicular thread  or  wire,  stretched 
through  its  middle,  and  in  the  other  sight 
there  is  a  narrow  perpendicular  slit.  The 
ring  of  the  gimbalds  rests  with  its  pivots 
on  a  semi-circle,  the  foot  of  which  turns 
in  a  socket,  so  that  whilst  the  box  is  kept 
steady,  the  compass  may  be  turned  round, 
in  order  to  place  the  sights  in  the  direc- 
tion of  the  sun. 

There  are  on  the  inside  of  the  box  two 
lines  drawn  perpendicularly  along  the 
sides  ;  these  lines  serve  to  shew  how  ma- 
ny degrees  the  north  or  south  pole  of  the 
needle  is  distant  from  the  azimuth  of  the 
sun. 

The  dipping-needle,  though  of  late  much 
improved,  is  still,  however,  far  from  per- 
fect. The  general  mode  of  constructing 
it  is  to  pass  an  axis  quite  through  the 
needle,  to  let  the  extremities  of  the  axis, 
like  those  of  the  beam  of  a  balance,  rest 
upon  its  supports,  so  that  the  needle  may 
move  itself  vertically  round,  and  when  si- 
tuated in  the  magnetic  meridian,  it  may 
place  itself  in  the  magnetic  line.  WThen 
it  is  used  at  sea,  it  is  suspended  by  a  ring. 
When  it  is  placed  upon  a  stand,  a  spirit- 
level  is  attached  to  it. 

The  greatest  imperfection  in  this  in- 
strument  is  in  the  balancing  of  the  needle, 
and  the  difficulty  of  ascertaining  whether 
the  needle  retains  its  equipoise.  In  ob- 
serving the  dip  of  the  needle  at  any  parti- 
cular place,  the  best  method  to  avoid  the 
error  arising  from  the  want  of  balance,  is, 
1st,  to  observe  the  dip  of  the  needle,  then 
to  reverse  its  magnetism,  by  the  magnetic 
bars,  so  that  the  end  of  the  needle,  which 
before  was  elevated  above  the  horizon, 
may  now  be  below  it ;  and,  lastly,  to  ob= 


MAG 


MAG 


serve  its  dip  again ;  for  a  mean  of  the  two 
observations  will  be  pretty  near  the  truth, 
though  the  needle  may  not  be  perfectly 
balanced. 

Theory  of  Magnetism. — It  was  mention- 
ed before,  that  the  earth  may  be  consi- 
dered as  a  great  magnet.  This  is  so 
clearly  evident  from  a  great  variety  of 
facts  and  observations,  that  there  can  be 
no  doubt  about  it. 

The  directive  property  and  dipping  of 
the  needle  upon  the  surface  of  the  earth, 
is  exactly  analogous  to  that  of  a  small 
magnet  upon  the  surface  of  a  small  globe, 
having  a  magnet  inclosed  within  it,  which 
apparatus  is  called  a  terrella. 

The  magnetism  which  iron  acquires  by 
its  position,  is  another  striking  indication 
of  the  earth's  magnetism.  The  immense 
masses  of  iron  in  various  states,  which  ex- 
ist  every  where  in  the  globe,  and  which 
are  often  magnetic,  prove  that  the  earth 
is  an  immense  magnet,  and  that  its  mag- 
netism arises  from  the  magnetism  of  all 
the  ferruginous  bodies  contained  in  it. 

The  cause,  however,  of  magnetic  at- 
traction and  repulsion,  is  utterly  unknown 
to  us,  nor  has  any  thing  farther  than  mere 
hypothesis  been  advanced  to  account  for 
this,  as  well  as  every  species  of  attrac- 
tion. The  most  ingenious  theory  is  that 
of  Aepinus. 

He  supposes  that  there  exists  a  pecu- 
liar fluid,  which  he  calls  the  magnetic 
jiuid>  which  is  so  subtile  as  to  penetrate 
all  bodies ;  and  that  it  is  of  an  elastic  na- 
ture, viz.  that  its  particles  are  repulsive 
of  each  other;  also,  that  there  is  a  mutual 
attraction  between  this  fluid  and  iron, but 
that  no  other  substance  has  any  action 
upon  it 

•  A  ferruginous  body,  according  to  this 
hypothesis'^  is  rendered  magnetic  by  hav- 
ing the  equable  diffusion  of  the  magnetic 
fluid  disturbed  throughout  its  substance, 
so  as  to  have  an  overplus  of  it  in  one  or 
more  parts,  and  a  deficiency  of  it  in  one  or 
other  parts  ;  and  it  remains  magnetic  as 
long  as  its  impermeability  prevents  the 
restoration  of  the  equal  diffusion  of  fluid, 
or  of  the  balance  between  the  overcharg- 
ed and  undercharged  parts.  Also  the 
piece  of  iron  is  rendered  magnetic,  by  the 
action  of  a  magnet;  because,  when  the 
overcharged  part,  or  pole  of  the  magnet, 
is  presented  to  it,  the  overplus  of  magne- 
tic fluid  in  that  pole  repels  the  magnetic 
fluid  away  from  the  nearest  extremity  of 
the  iron  (which,  therefore  becomes  under- 
charge*!), to  a  remote  part  of  the  irmi, 
w  hich  becomes  overcharged.  If  the  iron 
be  magnetized  by  the  contact  of  the  over- 
charged side  of  the  magnet,  then  the  mat- 


ter of  the  latter  attracts  the  magnetic  fluid 
of  the  iron,  to  that  extremity  of  the  iron 
which  lies  nearest  to  itself. 

Lay  a  sheet  of  paper  fiat  upon  a  table, 
strew  some  iron  filings  upon  the  paper, 
place  a  small  magnet  among  them,  then 
give  a  few  gentle  knocks  to  the  table,  so 
as  to  shake  the  filings,  and  you  will  find 
that  they  dispose  themselves  about  the 
magnet,  the  particles  of  iron  clinging  to- 
gether, and  forming  themselves  into  lines, 
which,  at  the  very  poles,  are  in  the  same 
direction  with  the  axis  of  the  magnet :  a 
little  sideway  of  the  poles  they  begin  to 
bend,  and  then  they  form  complete  arch- 
es, reaching  from  some  point  in  the  north- 
ern half  of  the  magnet  to  some  other 
point  in  the  southern  half.  The  reason  of 
this  is,  that  each  of  the  particles  of  iron  is 
actually  become  magnetic,  and  possessed 
of  the  two  poles  ;  in  consequence  of  which 
each  particle,  at  the  place  where  it  hap- 
pens to  stand,  disposes  itself  in  the  same 
manner  as  any  other  magnet  would  do  ; 
and,  moreover,  attracts,  with  its  extremi- 
ties, the  contrary  poles  of  other  particles. 

Take  a  strong  magnet,  and  find  out,  by 
trial,  such  a  piece  of  iron  as  is  very  little 
heavier  than  what  the  magnet  will  sup- 
port. It  is  plain,  that  if  you  affix  this  iron 
to  one  pole  of  the  magnet,  the  moment  you 
remove  your  hand  the  iron  will  drop  off. 

Hut  if,  before  you  remove  your  hand, 
you  present  another  larger  piece  of  iron 
to  the  under  part  of  the  former,  and  at 
about  half  an  inch  from  it,  you  will  then 
find  that  the  magnet  will  support  the  first 
piece  of  iron  which  it  could  not  support 
before,  when  the  secondary  piece  of  iron 
was  not  below  it.  In  short,  a  magnet  can 
lift  a  greater  weight  of  iron  from  over 
another  piece  of  iron,  such  as  an  anvil,  or 
the  like,  than  from  a  table;  the  reason  of 
winch  is,  that,  in  the  former  case,  the  iron 
basis,  or  inferior  piece  of  iron,  becoming 
itself  in  some  measure  magnetic,  helps  to 
increase  the  magnetism  of  the  first  piece 
of  iron,  and  consequently  tends  to  increase 
the  attraction. 

Summary  of  the  pri?icipal  facts  relative  to 
JMagv.etisru. 

1.  The  cause  of  magnetism  is  totally 
unknown ,  some  have  attributed  it  to  a  pe- 
culiar fluid,  which  they  have  called  the 
magnetic  fluid. 

2  Iron  is  the  only  known  body  that  is 
capable  of  being  possessed  of  magnetism. 

3.  I  very  magnet  has  two  opposite 
points.,  which  are  called  pules. 

4-  When  a  magnet  is  left  at  liberty  to 
move  freely,  it  places  itself  so  that  these 


MA  II 


MAH 


poles  point  nearly  north  and  south.  This 
is  culled  the  directive  property,  or  polarity 
of  the  mag-net. 

5.  When  two  magnets  approach  each 
other,  their  poles  of  the  same  names,  that 
is,  both  their  north  poles,  or  both  their 
south  poles,  repel  each  other. 

6.  But  poles  of  different  names  attract 
each  other. 

7.  The  earth  itself  appears  to  be  a  great 
magnet,  having  its  poles  near  to,  but  not 
coinciding  with  the  ends  of  the  imaginary 
axis,  on  which  it  turns. 

8.  Its  poles  act  upon  every  small  mag- 
net attracting  its  contrary  pole. 

9.  From  this  theory  the  dip,  or  inclina- 
tion of®  magnet  to  the  plane  of  the  hori- 
zon is  easily  explained. 

10.  The  deviation  of  the  direction  of  a 
magnet  from  due  north  and  south,  is  ow- 
ing to  the  situation  of  the  magnetic  poles 
of  the  earth,  and  is  called  the  declination 
of  the  magnet. 

11.  The  magnetic  poles  of  the  earth 
are  not  stationary,  but  are  continually 
changing  their  places. 

12.  This  occasions  a  constant  change 
of  the  declination,  and  this  is  called  the 
variation  of  the  compass. 

13.  The  loadstone  is  an  iron  ore  natu- 
r  rally  possessing  magnetism. 

14.  Magnetism  may  be  communicated 
to  iron  and  steel. 

15.  Pure  iron  most  easily  receives  mag- 
netism, but  loses  it  immediately. 

16.  Iron  combined  with  carbon,  as  hard 
iron  or  steel  retains  the  magnetic  proper- 
ties when  communicated  to  it. 

17.  A  steel  bar  rendered  magnetic,  and 
fitted  up  in  a  box,  so  as  to  move  freely  in 
every  direction,  constitutes  the  mariner's 
compass. 

MAHOGANY.  The  swietenia  maha- 
goni,  or  Mahogany  tree,  is  a  native  of  the 
warmest  parts  of  America,  and  grows 
in  the  island  of  Cuba,  Hispaniola,  and 
the  Bahama  islands.  It  abounded  for- 
merly in  the  low  lands  of  Jamaica,  but 
it  is  now  found  only  on  high  hills,  and 
places  difficult  of  access. 

This  tree  grows  tall  and  straight,  rising 
often  sixty  feet  from  the  spur  to  the  limbs ; 
and  is  usually  four  feet  in  diameter.  The 
foliage  is  a  beautiful  deep  geeen,  and  the 
appearance  made  by  the  whole  tree  so 
elegant,  that  none  could  be  more  orna- 
mental for  an  avenue.  The  flowers  are 
of  a  reddish  or  saffron  colour ;  and  the 
fruit  of  an  oval  form,  about  the  size  of  a 
turkey's  egg.  Some  of  them  have  reach- 
ed to  a  monstrous  size,  exceeding  one 
hundred  feet  in  height.  One  was  cut 
about  thirty  years  since  in  St.  Elizabeth's 
in  Jamaica,  which  measured  twelve  feet 


in  diameter,  and  cleared  to  the  proprietor 
.500/.  currency.  In  felling  these  trees  the 
most  beautiful  part  is  commonly  left  be- 
hind. The  negro  workmen  raise  a  scaf- 
folding of  four  or  five  feet  elevation  from 
the  ground,  and  hack  up  the  trunk,  which 
they  cut  up  into  balks.  The  part  below 
extending  to  the  root  is  not  only  of  larger 
diameter,  but  of  a  closer  texture  than  the 
other  parts,  most  elegantly  diversified  with 
shades  or  clouds,  or  dotted  like  ermine, 
with  black  spots  ;  it  takes  the  highest  po- 
lish, with  a  singular  lustre.  This  part  is 
only  to  be  come  at  by  digging  below  the 
spur,  to  the  depth  of  two  or  three  feet, 
and  cutting  it  through  ;  which  is  so  labo- 
rious an  operation  that  few  attempt  it,  ex- 
cept they  are  uncommonly  curious  in  the 
choice  of  their  wood,  or  to  serve  a  particu- 
lar order. 

The  mahogany  tree  thrives  in  most 
soils,  but  varies  in  texture  and  grain,  ac- 
cording to  the  nature  of  the  soil.  On  rocks 
it  is  of  a  smaller  size,  but  very  hard  and 
weighty,  and  of  a  close  grain,  and  beauti- 
fully shaded ;  while  the  produce  of  the 
low  and  richer  lands,  is  observed  to  be 
more  light  and  porous,  of  a  paler  colour 
and  open  grain;  and  that  of  mixed  soils 
to  hold  a  medium  between  both.  This 
constitutes  the  difference  between  the  Ja- 
maica wood  and  that  which  is  collected 
from  the  coast  of  Cuba  and  the  Spanish 
Main,  the  former  is  mostly  found  on  rocky 
eminences,  the  latter  is  cut  in  swampy 
soils  near  the  sea  coast.  The  superior 
value  of  the  Jamaica  wood,  for  beautv  oi 
colouring,  firmness,  and  durability,  ma} 
therefore  be  easily  accounted  for ;  but  as 
a  large  quantity  of  balks  and  planks  is 
brought  from  the  Spanish  American  coasts 
to  Jamaica,  to  be  shipped  from  thence  to 
the  United  States,  the  dealers  are  apt  to 
confound  all  under  the  name  of  Jamaica 
wood,  which  in  some  measure  hurts  the 
credit  of  this  staple  production. 

This  wood  is  generally  hard,  takes  a  fine 
polish,  and  is  found  to  answer  better  than 
any  other  sort,  in  all  kinds  of  cabinet 
ware.  It  is  a  very  strong  timber,  and  was 
frequently  used  as  such  in  Jamaica,  in 
former  times.  It  is  said  to  be  used  some- 
times in  ship  building  ;  a  purpose  for 
which  it  would  be  remarkably  adapted  if 
not  too  costly  :  being  very  durable,  capa- 
ble of  resisting  gun  shots,  and  burying 
the  shots  without  splintering. 

It  was  not  till  the  commencement  of  the 
last  century  that  mahogany  was  imported 
with  the  view  of  making  household  furni- 
ture of  it.  The  carpenters  in  the  begin- 
ning found  this  wood  much  too  hard  for 
their  tools,  and  it  was  some  time  before 
this  difficulty  was  overcome.    The  prac 


MAL 


MAL 


tice  of  veneering  is  much  used  in  this 
country. 

MAIZE,  Indian  corn.  See  Agricul- 
ture. 

MALT,  is  barley  prepared  for  brewing 
into  beer,  ale,  and  porter.    See  Brew- 

IN  G. 

MALTING,  an  operation  of  making- 
malt.    See  Brewing. 

Besides  the  remarks  we  have  made  on 
malt,  it  may  be  proper  to  add,  that,  in 
order  to  determine  the  quality  of  malt,  a 
handful  of  it  should  be  thrown  into  cold 
water,  where  those  grains  that  are  imper- 
fectly germinated,  will  swim  with  one  end 
upwards  (Dr.  Darwin  supposes  with  the 
root  end)  j  and  such  as  are  properly  malt- 
ed, float  on  their  side ;  whereas  sound, 
ungerminated  barley,  uniformly  sinks  in 
water.  Another  criterion  of  good  malt 
is,  its  agreeable  saccharine  taste ;  and, 
when  the  whole  contents  of  the  grain 
easily  crumble  into  powder,  and  dis- 
solve in  the  mouth.  In  short,  it  ought 
to  be  pure,  dry,  and  to  emit  a  strong, 
agreeable  odour. 

Malt-dust,  or  the  refuse  that  fulls  from 
malt  in  drying,  affords  an  advantageous 
manure  for  wheat  land,  especially  if  it  be 
scattered  as  a  top-dressing.  The  proper 
quantity  of  this  dust  is  80  bushels  per  acre 
for  wheat,  and  about  60  bushels  for  bur- 
ley  :  it  is  also  eminently  calculated  for 
grass-lands  ;  and,  if  applied  in  the  latter 
proportion,  it  will  produce  a  very  consi- 
derable increase  of  the  best  seed.  Such 
manure,  however,  is  most  beneficial  to 
clay  soils,  or  stiff  loams  ;  as,  on  gravelly 
land,  and  in  dry  seasons,  it  will  be  apt  to 
burn  the  soil.  But,  if  the  succeeding 
weather  be  moist,  it  will  be  productive  of 
great  benefit ;  for  the  first  shower  washes 
it  into  the  earth,  and  thus  secures  the 
crop,  which  not  only  becomes  finer  and 
more  abundant,  but  the  soil  is  at  the  same 
time  effectually  cleared  from  the  noxious 
weeds,  that  frequently  vegetate,  when 
common  dung*  is  employed. 

As  malt  forms  so  essential  an  article  of 
domestic  consumption,  and  is  not  at  all 
times  within  the  reach  of  the  poor,  various 
recipes  have  been  given  for  making  beer 
with  a  small  portion  of,  or  wholly  without 
malt.  We  add  the  following  method  of 
brewing  beer,  as  tending  to  diminish  the 
consumption  of,  and  thus  in  some  mea- 
sure to  serve  as  a  substitute  for,  that  va- 
luable grain.  It  consists  simply  in  adding 
281bs.  of  dry,  well-tasted  brown  sugar,  to 
half  a  load,  or  three  Winchester  bushels 
of  malt.  The  latter  is  to  be  brewed  in 
the  usual  manner  with  hops,  after  which 
the  sugar  is  to  be  introduced,  and  the  li- 1 
-quor  stirred  till  the  whole  is  dissolved. ! 


Thus,  a  wholesome  beverage  maybepro- 
cured  at  about  three-fourths  of  the  ex- 
pence  usually  incurred  by  using  malt  and 
hops  only  ;  because  a  smaller  proportion 
of  the  latter  plant  now  answers  the  pur- 
pose. 

Among  the  different  patents  that  have 
been  granted  for  inventions,  or  improve- 
ments, relative  to  the  preparation  of  beer, 
the  following  claim  more  particular  no- 
tice ;  namely,  Mr.  Dearman's  for  his  con- 
trivance oi'  mills  for  grinding  malt,  in 
1779  ;  Mr.  Jones's  in  1798,  f or  a  machine, 
calculated  to  mix  malt,  or  other  substan- 
ces, more  intimately  with  fluids  ;  and  Mr. 
Tickle's,  in  1801,  for  more  effectually  dis- 
solving and  extracting  the  virtues  ot  malt, 
hops,  and  other  vegetable  substances.  As 
our  limits  will  not  permit  us  to  detail  these 
pretensions  to  ingenuity,  we  refer  the 
reader  to  the  later  volumes  of  the  Reper- 
tory of  Jrts  and  Manufactures.  In  the  15th 
volume  of  the  same  work,  we  meet  with  a 
communication  from  Mr.  Joseph  Coppin- 
ger,  containing  a  description  and  plan  of 
a  malt  and  corn-kiln  of  ids  invention.  He 
observes,  that  it  is  particularly  adapted  to 
the  use  of  farmers,  who  frequently  lose 
considerable  quantities  of  grain  during 
damp  or  wet  seasons,  for  want  of  a  simi- 
lar contrivance.  Its  advantages  are  stated 
to  be  :  1.  That  it  may  be  erected  either  in 
a  loft  or  on  the  ground-floor,  and  at  one- 
tenth  part  of  the  expence-  2.  Any  kind 
of  fuel  may  be  employed  without  detri- 
ment to  the  malt  or  corn  dried  in  it.  3. 
The  heat  will  be  more  uniformly  distribut- 
ed, without  any  waste,  as  is  the  case  with 
most  of  the  common  kilns.  Lastly,  the 
health  of  the  attendants,  necessarily  em- 
ployed, will  not  be  exposed  to  certain  in- 
jury, in  consequence  of  their  breathing, 
or  sleeping  in  an  unwholesome  atmo- 
sphere ;  as^their  beds  will  be  placed  in  a 
shed  on  the  outside  of  the  building.  This 
circumstance,  being  of  the  greatest  im- 
portance, deserves  serious  attention  ;  and 
we  trust  that  the  contrivance  here  sug- 
gested, will  be  generally  adopted. 

MALT  SPIRITS,  are  liquors  made 
from  malt,  in  which  distillation  is  used, 
and  comprehends  all  those  fluids  in  which 
malt  is  used  in  their  preparation.  See  S  pi- 
rit,  Alcohol,  &c. 

MALVOIS1E,  to  imitate.  Take  of  the 
best  galangal,  cloves  and  ginger,  each  one 
drachm  ;  bruise  them  coarstly,  and  infuse 
for  twenty-four  hours,  with  brandy,  in  a 
well  closed  vessel ;  then  take  these  drugs 
out,  and  having  tied  them  in  a  linen  bag, 
let  them  hang  in  the  cask  by  the  bung- 
hole.  Three  or  four  days  after,  your  wine 
will  taste  as  good  and  as  strong  as  natural 
Malvoisie.  Imisox. 


MAN 


MAN 


MALTHEA.  See  Bitumen. 

MANGE.  See  Farriery;  also  Ani- 
mals, domestic. 

MANGANESE  Manganese  is  a  metal 
of  an  iron-grey  colour,  brittle,  and  easily 
oxydable  on  exposure  to  the  air.  When 
in  "the  state  of  black  oxyd  it  communi- 
cates to  borax  a  red  tinge,  which  is  de- 
stroyed by  the  internal  blue  flame  of  the 
blow-pipe,  but  is  restored  by  the  external 
flame  or  the  addition  of  nitre. 

Ores  of  Manganese. 

Sp.  1.  Grey  Manganese. 

Of  this  there  are  reckoned  the  four  fol- 
lowing subspecies. 

1.  Subsp.  Radiated  grey  manganese. 

2.  Subsp.  Foliated  grey  manganese. 

3.  Subsp  Compact  grey  manganese. 

4.  Subsp  Earthy  grey  manganese. 
Sp.  2.  Attack  manganese. 

Sp.  3.  White  manganese. 

Sp.  4.  Red  manganese. 

Sp.  5.  Sulphuret  of  manganese. 

Sp.  6.  Phosphat  of  manganese  and  iron. 
Reduction  of  Ores. 

As  manganese  is  applied  to  no  use  in 
its  metallic  state,  there  are  no  establish- 
ments for  the  reduction  of  its  ores  in  the 
greJt  way  ;  and  even  in  the  laboratory  the 
process  is  seldom  performed,  chiefly  on 
account  of  the  intense  heat  which  is  re- 
quisite, and  which  cannot  be  obtained  in 
small  furnaces  unless  they  are  peculiarly 
well  constructed.  The  use  of  all  alkaline 
and  vitreous  fluxes  must  be  carefully 
avoided  ;  for  the  affinity  of  these  with  the 
oxyd  of  manganese  is  so  considerable  as 
entirely  to  prevent  its  reduction  where 
they  are  present.  The  only  method  which 
lias  been  attended  with  any  tolerable  suc- 
cess is  the  following,  invented  by  Berg 
man.  Select  a  sound  and  very  refractory 
crucible  and  line  it  with  charcoal,  or  still 
better  with  a  mixture  of  linseed  meal  and 
water,  beaten  up  with  as  much  finely  sift- 
ed charcoal  as  it  will  take  without  losing 
its  tenacity  ;  dry  the  crucible  thoroughly, 
gradually  increasing  the  heat  till  the  meal 
begins  to  be  scorched ;  then  take  some 
oxyd  of  manganese  (purified  from  all  ex- 
traneous substances  as  described  in  the 
last  section)  and  make  it  up  into  a  ball 
with  any  kind  of  oil ;  put  this  into  the  ca- 
vity of  the  crucible  and  cover  it  with  pow- 
dered charcoal ;  then  lute  on  a  pierced 
cover  or  an  inverted  crucible,  and  place  it 
in  a  blast  furnace  ;  keep  it  at  a  moderate 
red  heat  till  the  jet  of  blue  flame  through 
the  hole  in  the  cover  has  ceased,  then 
bring  the  furnace  rapidly  to  its  highest 
heat,  and  keep  it.  so  for  forty  minutes  or 
three  quarters  of  an  hour  :  after  this  let 
the  fire  go  out,  and  when  the  crucible  is 
quite  cold,  break  it  up  carefully  and  the 


manganese  will  be  found  in  globules  ot" 
various  sizes  covered  for  the  most  part 
with  a  thin  vitreous  crust.  It  appears 
probable  that  a  button  might  be  obtained 
by  a  second  fusion  of  these  globules  with 
glass  of  borax,  in  a  crucible  lined  with 
charcoal  and  a  little  pipe -clay  to  prevent 
the  flux  from  sinking  through  the  pores 
of  the  charcoal. 

Some  of  the  physical  and  chemical  proper- 
ties of  manganese 
The  colour  of  manganese  is  greyish- 
white  with  a  considerable  metallic  bril- 
liancy. Its  fracture  is  uneven  granular : 
its  hardness  is  somewhat  greater  than  that 
of  cast  iron ;  and  it  is  very  brittle.  Its 
sp.  gr.  according  to  Bergman,  is  6.85,  ac- 
cording to  Hielm  is  7.  In  fusibility  it  ap- 
pears to  rank  between  platina  and  iron: 
when  pulverized  it  is  feebly  attracted  by 
the  magnet,  but  this  is  probably  owing  to 
the  presence  of  iron,  from  which  it  is  sel- 
dom absolutely  free. 

No  other  metal  is  so  easily  oxydable  as 
this.  If  a  globule  of  manganese  be  broken 
and  exposed  to  the  air,  the  fractured  sur- 
face almost  immediately  loses  its  metallic 
lustre  and  acquires  a  greyish  tarnish  ;  in 
a  few  seconds  more  it  becomes  lilac  co- 
loured, then  violet,  and  lastly  brownish- 
black  ;  when  in  this  state,  it  is  friable  and 
breaks  down  between  the  fingers  into  a 
black  powder,  resembling  in  appearance 
the  native  grey  oxyd.  It  is  by  no  means 
however  as  yet  at  a  high  degree  of  oxy- 
dation,  for  when  treated  with  dilute  sul- 
phuric acid  it  gives  out  hydrogen  gas ; 
after  a  few  days  however  of  exposure  to 
the  atmosphere  it  becomes  more  saturated 
with  oxygen  and  then  loses  this  propertv. 
When  heated  below  ignition  in  contact 
with  atmospheric  air,  nearly  the  same  ef- 
fect takes  place  as  at  the  common  tem- 
perature, only  more  rapidly. 

Chemists  at  present  distinguish  three 
degrees  of  oxydation  of  this  metal,  each  of 
which  is  characterized  by  a  remarkable 
change  of  colour.  The  white  oxyd  con- 
tains the  smallest  proportion  of  oxygen, 
and  the  black  oxyd  the  largest ;  the  red 
oxyd  holds  an  indeterminate  place  be- 
tween the  two  others. 

The  only  use  of  manganese  is  in  the 
state  of  black  oxyd.  It  is  employed  in  the 
laboratory  as  the  cheapest  and  most  con- 
venient material  from  which  to  procure 
oxygen  gas.  All  the  oxymuriatic  acid 
consumed  in  the  bleacheries  in  Europe  is 
prepared  from  manganese  and  the  usual 
materials  of  muriatic  acid.  Finally  it  is 
largely  employed  by  the  glass-makers, 
both  as  a  colouring  material  and  for  the 
purpose  of  destroying  the  colour  of  the 


MAN 


MAN 


finer  kinds  of  glasses  ;  hence  its  common 
appellation  of  glass  soap.  It  may  be  re- 
marked by  the  bye  that  this  latter  applica- 
tion of  manganese  to  the  purposes  of  art 
is  by  far  the  most  ancient,  it  being  distinct- 
ly mentioned  by  Pliny  in  his  Natural  His- 
tory, whereas  the  others  do  not  date  fur- 
ther back  than  the  commencement  of 
pneumatic  chemistry.  Manganese  has 
been  discovered  in  the  United  States. 

MANGLE,  a  machine  for  smoothing 
linen  which  cannot  be  ironed.  There  are 
various  forms  of  mangles.  Without  de- 
scribing them,  we  shall  here  introduce  an 
improved  one,  for  an  account  of  which  we 
are  indebted  to  Dr.  Mease. 

The  celebrated  mangle  of  Mr.  Jee  was 
found  on  trial  in  this  city  to  be  defective, 
or  not  to  work  as  well  as  described,  and 
required  withal  great  power.  Mr.  Morris, 
of  London,  has  lately  obtained  a  patent  for 
one,  of  which  the  following  is  a  descrip- 
tion. Dr.  Mease  informs  us,  that  this 
mangle  is  now  in  general  use  in  England. 


Description. — Two  horizontal  cylindri- 
cal rollers  form  a  bed  for  the  roller  on 
which  the  linen  to  be  mangled  is  rolled. 
One  ©f  them,  b,  is  seen  in  the  drawing. 
The  axis  of  those  rollers  bear  on  brass, 
let  into  the  wood  frame,  and  have  a  wheel 
fixed  to  each,  which  works  in  a  pinion  on 
the  axis  of  the  fly  wheel,  as  seen  in  the 
drawing  :  c,  a  moveable  roller  on  which 
the  linen  to  be  mangled  is  rolled :  d,  a 
roller,  the  axis  of  which  worksjn  pieces 
of  brass  which  slide  between  iron,  let  in- 
to the  inner  side  of  the  wood  frame,  to 
the  bottom  of  which,  long  pieces  of  iron, 
Jy  are  fixed  with  hooks  at  their  lower  ex- 
tremities, to  which  are  attached  the  chains 
that  support  the  scale  or  platform,  hy 
where  iron  weights,  or  any  other  heavy 
substance,  are  placed  ;  to  the  top  of  the 
brass  in  which  the  roller  d  works,  the  en- 
gine chains  are  fastened,  which  pass 


through  apertures  at  each  end  of  the  lop 
of  the  wood  frame,  and  are  there  again 
fastened  on  the  pulleys  of  the  shaft  k  with 
a  screw  :  /  is  a  lever  fixed  to  the  end  of 
the  shaft  k. 

To  use  the  machine,  press  the  lever  l> 
and  fasten  it  with  the  hook,  which  raises 
the  roller  d  with  the  platform  and  weights 
attached  to  it ;  then  take  out  the  roller  c, 
and  roll  the  linen  and  mangling  cloth 
round  it,  and  replace  it  on  the  two  bot- 
tom rollers,  unhook  the  lever  /,  and  the 
weights  on  the  platform  will  press  the 
roller  d  on  the  roller  c ;  give  motion  to  the 
fly  wheel,  and  also  to  all  the  rollers,  by 
turning  the  handle  m,  which  in  a  short 
time  will  make  the  linen  beautifully 
smooth ;  press  down  the  lever,  fasten  it 
with  the  hook,  and  take  the  roller  c  out  : 
a  spare  roller  is  supplied,  so  that  if  two 
people  are  employed,  one  may  be  filling 
it  with  linen,  while  the  other  is  mangling. 

None  of  the  recent  improvements  in 
machinery  have  excited  so  much  general 
attention  as  this  machine;  being  construct- 
ed on  true  mechanical  principles,  and 
worked  by  one  person  with  the  greatest 
ease.  From  experiments  which  havejpeen 
tried  with  it,  it  is  found  it  will  pass %ver 
all  inequalities  without  the  least  difficulty 
or  obstruction,  the  top  cylinders  and 
weights  rising  and  falling  as  they  ap- 
proach ;  from  the  two  bottom  cylinders 
being  put  a  little  asunder,  the  one  on 
which  the  linen  is  rolled  acts  as  a  wedge, 
greatly  increasing  the  power  of  the 
weights,  giving  the  linen  three  equal 
pressures.  Upon  the  whole,  this  machine 
mangles  with  greater  ease,  performs  its 
work  better,  and  with  more  expedition, 
than  any  machine  before  invented  ;  is  very 
compact  in  its  construction,  and  never 
subject  to  be  out  of  repair. 

MANUFACTURE  of  Alum.  See  Alum. 
Manufacture  of  Annatto.    See  Antfatto. 
Manufacture  of  Aqua  Fortis.    See  Ni- 
tric Acid. 

Manufacture  of  Barilla.  See  Soda  and 
Barilla. 

Manufacture  of  Baskets. — Baskets  are 
made  of  willows,  which,  according  to 
their  manner  of  growth,  are  called  osiers 
and  sallows.  They  thrive  best  in  moist  pla- 
ces ;  and  the  proprietors  of  such  marsh 
lands  in  Europe,  generally  let  what  they 
call  the  willow-beds  to  persons  who  cut 
them  at  certain  seasons,  and  prepare  them 
for  basket-makers.  To  form  an  osier-bed, 
the  land  should  be  divided  into  plots  six, 
eight,  or  ten  feet  broad,  by  narrow  ditch- 
es ;  and  if  there  is  a  power  of  keeping  wa- 
ter in  these  cuts  at  pleasure,  by  means  of 
a  sluice,  it  is  highly  advantageous  in  ma- 
ny seasons.  Osiers  planted  in  small  spots, 


MAN 

and  aloug  hedges,  will  supply  a  farmer 
with  hurdle-stuff,  as  well  as  with  a  profu- 
sion of  all  sorts  of  baskets.  The  common 
osier  is  cut  at  three  years,  but  that  with 
yellow  bark  is  permitted  to  remain  a  year 
longer. 

When  the  osiers  are  cut  down,  those 
that  are  intended  for  white  work,  such  as 
baskets  used  in  washing-,  are  to  be  stripp- 
ed of  their  bark,  or  rinds,  while  green. 
This  is  done  by  means  of  a  sharp  instru- 
ment, fixed  into  a  firm  block:  the  osiers 
are  passed  over  this,  and  stripped  of  their 
covering-  with  great  velocity.  They  are 
then  dried,  and  put  in  bundles  for  sale- 
Before  they  are  worked  up,  they  must  be 
previously' soaked  in  water,  which  gives 
them  flexibility. 

Hampers  and  other  coarse  work  are 
made  of  osiers,  without  any  prepara- 
tion except  soaking-.  Some  expert  work- 
men make  a  variety  of  articles  of 
wicker  manufacture,  as  work-baskets  of 
different  descriptions.  The  ancient  Bri- 
tons were  celebrated  for  their  ingenuity 
in  manufacturing*  baskets  of  very  elegant 
workmanship,  which  they  exported  in 
large  quantities. 


.  MAN 

The  American  Indians,  in  particular, 
are  very  expert  and  ingenious  in  this  art  : 
besides  forming  baskets  of  different 
shapes  and  fashions,  they  colour  or  dye 
the  substance  of  which  they  are  made  ot 
different  colours,  principally  obtained 
from  indigenous  plants.  See  Bartram's 
Travels  among  the  Indians. 

Manufacture  of  Beer  and  Ale.  See 
Brewing. 

Manufacture  of  Brass.  See  brass,  cop- 
per, zinc. 

Manuf  acture  of  Bread.    See  Bread. 

Manufacture  of  Brimstone.  See  Sul- 
phur. 

Manufacture  of  Butter.    See  Butter. 

Manufacture  of  Buttons.  There  are  se- 
veral kinds  of  buttons  ;  some  made  of  gold 
and  silver  lace,  others  of  mohair,  silk,  8tc. 
and  others  of  metal.  The  figure  repre- 
sents a  man  who  makes  or  stamps  metal 
buttons  only.  The  process  is  very  sim- 
ple, after  the  metal  comes  out  of  the  foun- 
der's hands. 

The  pieces  of  metal  are  either  cast  or 
cut  to  the  proper  size,  and  then  sent  to 
the  button-maker,  who  has  dies  or  stamps 


VOL.  II, 


r 


MAN 


MAN 


according  to  the  pattern  wanted.  The 
machine  by  which  they  are  stamped,  is 
well  exhibited  in  the  figure.  The  man 
stands  in  a  place  lower  than  the  floor,  by 
which  he  is  nearer  on  a  level  with  the 
place  on  which  his  dies  stand  s  by  means 
of*  a  single  pulley  he  raises  a  weight,  to 
the  lower  part  of  which  is  fixed  another 
die ;  he  lets  the  weight  fall  down  on  the 
metal,  and  the  thing  is  done.  After  this 
operation  they  are  to  be  shanked  ;  which 
is  performed  by  means  of  solder :  they 
are  then  polished  by  women.  At  Birm- 
ingham, (Eng.)  this  manufacture  is  car- 
ried on  upon  a  very  large  scale.  The 
late  John  Taylor,  esq.  was  the  inventor  of 
gilt  buttons ;  and  in  his  house,  buttons 
have  been  manufactured  to  the  amount 
of  800/.  per  week.  This  manufacture 
will  be  presently  noticed. 

Besides  those  cast  in  a  mould,  there 
are  great  quantities  of  buttons  made  of 
thin  plates.  The  plates  are  brought  to  a 
proper  degree  of  thickness  by  the  rolling- 
mill  :  they  are  then  cut  into  round  pieces 
of  the  size  wanted.  Each  piece  of  metal 
thus  cut,  is  reduced  to  the  form  of  a  but- 
ton by  beating  it  in  several  spherical  cavi- 
ties, beginning  with  the  flattest  cavity, 
and  proceeding  to  the  more  spherical,  till 
the  plate  has  got  all  the  relievo  required; 
and,  the  more  readily  to  manage  so  thin  a 
plate,  ten  or  a  dozen  of  them  are  formed 
to  the  cavities  at  once.  As  soon  as  the 
inside  is  formed,  an  impression  is  given  to 
the  outside,  by  working  it  with  an  iron 
puncheon,  in  a  kind  of  mould  like  mint- 
ers'  coins,  engraven  indentedly,  and  fast- 
ened to  a  block  or  bench.  The  cavity  of 
the  mould  in  which  the  impression  is  to 
be  made,  is  of  a  diameter  and  depth  suit- 
able to  the  sort  of  button  to  be  struck  in 
it ;  each  kind  requiring  a  particular  mould. 

The  plate,  thus  prepared,  makes  the 
upper  part  or  shell  of  the  button.  The 
lower  part  is  formed  of  another  plate, 
made  after  the  same  manner,  but  flatter, 
and  without  any  impression.  To  this  is 
soldered  a  little  eye,  made  of  wire,  for 
the  button  to  be  fastened  by. 

The  two  plates  are  soldered  together 
with  a  wooden  mould,  covered  with  wax 
or  rosin  between,  to  render  the  button  so- 
lid and  firm  ;  for  the  wax  or  other  cement 
entering  all  the  cavities  formed  by  the  re- 
lievo of  the  other  side,  sustains  it,  pre- 
vents its  flattening,  and  preserves  its  de- 
sign. 

Buttons  may  be  made  of  tin,  in  imitation 
of  worked  buttons  of  gold  and  silk  in  the 
following  manner : 

Take  lamp-black ;  grind  it  with  oil  of 
spike,  and  mark  the  ground-work  with  a 
pencil ;  when  dry,  draw  it  all  over  with 


varnish  :  the  best  way  to  imitate  worked 
buttons  is,  to  do  them  in  a  fine  mould, 
either  stamped  or  cast ;  the  ground  is  first 
filled  up  with  black,  blue,  red,  or  any 
other  colour ;  then  the  raised  part  is  to 
be  wiped  very  clean,  and  when  dry,  to  be 
drawn  over  with  the  varnish,  which  will 
make  it  look  much  finer  than  what  can  be 
done  upon  a  plain  button. 

For  a  brown  colour  take  umber. 

For  green  take  distilled  verdigrise, 
mixed  with  other  colours,  to  make  it  eith- 
er deeper  or  lighter. 

For  grey  take  white  lead,  and  lamp- 
black. 

All  your  colours  must  be  ground  with 
oil  of  spike. 

In  this  manner  you  may  embellish  pew- 
ter, with  a  coat  of  arms,  cypher,  or  orna- 
ments ;  that  is,  such  pewter  things  as  are 
not  to  be  scowered. 

The  following  is  a  brief  account  of  Gilt 
Buttons,  comprising  some  improvements, 
important  to  manufacturers.  Communi 
cated  by  Messrs.  Collard  and  Frazer,  of 
Birmingham,  to  A.  Tilloch. 

As  the  means  employed  in  the  manu- 
facture of  plain  gilt  buttons  are  not  uni 
versally  known,  the  following  summary, 
while  it  points  out  to  the  manufacturer 
many  considerable  advantages,  in  the  use 
and  recovery  of  his  mercury,  will  also,  it  is 
hoped,  be  found  interesting  to  many  of 
our  readers. 

The  copper,  properly  alloyed,  is  first 
taken  to  a  rolling  mill,  and  reduced  be- 
tween iron  rollers  to  a  proper  thickness 
for  the  button.  The  sheets  of  copper  are 
then  brought  to  the  button  manufactory, 
and  cut  into  circular  pieces  of  the  size  of 
the  intended  button,  by  means  of  a  fly- 
press.  In  this  state  they  are  called  blanks, 
and  resemble  halfpence  and  farthings 
worn  smooth  by  long  circulation. 

The  shanks,  which  are  made  with  won- 
derful facility  and  expedition  by  means  of 
a  very  curious  machine,  are  then  secured 
to  the  bottom  of  each  button  by  a  small 
iron  crank,  and  a  small  quantity  of  solder 
and  rosin  applied  to  each.  Thus  they  are 
placed  on  a  sheet  of  iron,  containing  about 
a  gross,  and  introduced  into  a  very  hot 
stove,  where  they  remain  till  the  work- 
man is  satisfied  that  the  solder  has  melt- 
ed, and  that  the  shanks  are  united  to  the 
button  ;  after  which  the  edges  are 
smoothed  in  a  lathe. 

The  next  process  is  what  they  call  dip. 
ping;  that  is,  a  quantity,  consisting  of  a 
few  dozens,  is  put  into  an  earthen  vessel 
full  of  small  holes  like  a  cullender,  and 
thus  dipped  into  diluted  nitric  acid  to 
clean  them  from  dirt  and  rust.  They 
then,  according  to  the  best  practice,  go  ui* 


MAN 


MAN 


to  the  hands  of  the  burnisher,  who,  in  a 
lathe,  burnishes  the  tops,  bottoms,  and 
edges,  with  a  hard  black  stone,  got  from 
Derbyshire,  (Eng.)  secured  in  a  handle 
like  the  diamond  of  a  glazier  :  this  he  ap- 
plies to  the  button  fixed  in  the  end  of  a 
piece  of  wood,  turned  with  great  velocity 
by  means  of  a  treddle  with  which  he 
works  the  lathe.  This  is  called  rough  bur- 
nishing, and  is  a  modern  improvement :  it 
is  of  great  advantage,  for  it  closes  the 
pores  of  the  metal  opened  by  the  acid,  so 
that  the  gold  afterwards  to  be  applied, 
attaches  to  a  smooth  surface,  which  other- 
wise might  enter  into  imperceptible  cavi- 
ties, and  be  closed  up  in  the  body  of  the 
button  by  the  final  burnishing.  When  the 
buttons  come  from  the  burnisher  they  are 
fit  for  gilding.  This  is  a  very  curious  ope- 
ration, and  truly  chemical. 

The  first  process  towards  gilding,  is 
what  they  call  quicking,  which  is  effected 
as  follows  : — Any  given  quantity  of  but- 
tons, perhaps  a  gross,  is  put  into  an  earth- 
en vessel,  with  a  quantity  of  mercury, 
which  has  been  previously  saturated  with 
nitric  acid ;  and  thus  the  buttons  and  mer- 
cury are  stirred  together  with  a  brush  till 
the  mercury,  carried  by  the  affinity  of  the 
acid  to  the  copper,  adheres  to  the  whole 
surface  of  the  button.  The  buttons  are 
then  taken  out,  and  put  into  what  is  call- 
ed a  basket,  though  in  fact,  an  earthen  ves- 
sel full  of  small  holes,  the  handle  of  which 
the  operator  holds  in  his  hand,  and  jerks 
it  with  considerable  force  down  towards 
a  wooden  trough  (a  receptacle  for  the 
quicksilver)  till,  by  repeated  jerks,  all  the 
loose  particles  of  mercury  are  disengag- 
ed, leaving  a  complete  continuity  over 
the  surface,  and  giving  them  the  appear- 
ance of  silver  buttons. 

Now  the  gold,  a  grain  of  which  will 
spread  over  many  superficial  feet  of  cop- 
per, is  thus  prepared  :  Any  given  quantity 
of  mercury  is  poured  into  an  iron  ladle,  the 
inside  of  which  having  been  previously 
guarded, — that  is,  rubbed  over  with  dry 
whiting  to  prevent  the  gold  from  adhe- 
ring to  the  iron, — into  this  mercury  is 
thrown  the  portion  of  pure  gold  intended 
to  cover  a  given  quantity  of  buttons.  The 
gold  and  mercury  are  heated  together  in 
the  iron  ladle  till  the  workman  (whose 
practice  soon  enables  him  to  judge)  per- 
ceives that  there  is  a  perfect  union  be- 
tween them  ;  when  he  empties  his  ladle 
into  a  vessel  containing  cold  water. 

The  amalgam  being  cold,  is  put  into  a 
piece  of  shamoy  leather,  and  squeezed 
till  no  more  mercury  will  pass  through. 
What  passes  the  shamoy  contains  not 
the  smallest  portion  of  gold  ;  what  re- 
mains wifl  be  about  the  consistency  of 


butter,  so  completely  united,  that  evert 
particle  of  mercury  shall  contain  an  equal 
portion  of  gold.  The  amalgam  should  be 
then  put  into  an  earthen  vessel,  and  a 
small  quantity  of  nitric  acid  added  there- 
to, allowing  sufficient  time  for  the  acid  to 
unite  with  the  mercury.  But  the  buttons 
and  amalgam  are  commonly  introduced 
first,  and  a  quantity  of  diluted  nitric  acid 
added  thereto,  so  that,  for  want  of  a  com- 
plete union  between  the  mercury  and  acid 
first,  if  there  be  not  a  superabundancy  of 
acid,  there  may  not  be  sufficient  to  carry 
all  the  amalgam  to  the  surface  of  the  but- 
tons. 

When  the  acid  has  had  sufficient  time 
to  embrace  (as  workmen  call  it)  the  mer- 
cury, the  buttons  should  be  introduced, 
and"  be  stirred  till  the  amalgam,  carried 
by  the  affinity  of  the  acid  to  the  copper, 
and  the  tendency  which  the  gold  has  to 
extend  itself  to  the  mercury  with  which 
the  buttons  have  been  previously  quicked, 
completely  attaches  to  the  whole  surface. 

It  is  the  next  process  in  which  we 
principally  wish  to  recommend  a  deviation 
from  the  old  practice,  by  which  most  of 
the  mercury  will  be  recovered,  and  the 
gilder's  health,  in  a  great  measure,  pre- 
served  from  the  dreadful  effects  of  vola- 
tilised mercury. 

The  old  practice  is  as  follows  :  The 
buttons  being  completely  covered  with 
mercury  and  gold,  the  operator  proceeds 
to  that  business  which  is  called  drying  off, 
which  is  performed  thus  :  The  buttons,  to 
the  quantity  of  a  few  dozens,  are  put  into 
an  iron  pan  somewhat  like  a  large  frying- 
pan,  placed  over  a  fire,  and  gently  shook, 
while  the  operator  watches  carefully  till 
he  observes  the  mercury  begins  to  flow  ; 
upon  the  first  symptom  of  which ;  he  takes 
the  pan  from  the  fire,  and  throws  the  but- 
tons into  a  large  cap,  called  a  gilding  cap, 
like  a  man's  hat  with  a  very  small  brim, 
but  much  larger  in  the  crown,  made  of 
coarse  wool  and  goats  hair.  In  this  cap, 
with  a  circular  brush,  the  buttons  are 
stirred,  to  spread  the  gold  and  mercury 
while  in  a  degree  of  temperature  nearly 
sufficient  to  volatilise  the  mercury.  The 
buttons  are  again  thrown  into  the  pan, 
placed  over  the  fire,  and  shaken,  while 
the  mercury  gently  volatilises.  The  but- 
tons are  again  thrown  into  the  cap,  and 
stirred  with  the  brush.  This  process  is 
continually  repeated,  till  all  the  mercury 
is  volatilised,  leaving  the  gold  on  the  but- 
tons, which  appear  again  of  a  yellow  co- 
lour. 

Thus  a  principal  part  of  the  mercury 
ascends  the  chimneys,  is  deposited  on  the 
tops  of  the  houses  and  about  the  adjacent 
neighbourhood,  and  great  quantities  are 


MAN 


MAN 


inhaled  and  absorbed  by  the  operator, 
keeping  him  nearly  in  a  slate  of  salivation 
till  disease  obliges  him  to  desist. 

Considerable  quantities  of  mercury  thus 
volatilised  are  found  united  and  collected 
in  small  pools  in  the.  spouts  and  gutters  on 
the  tops  of  the  buildings.  Thus  many 
tons  of  mercury  have  been  dissipated 
about  the  town  of  Birmingham,  (Eng.)  to 
the  great  injury  of  the  inhabitants.  The 
poor  sweep  who  has  ascended  the  chim- 
neys has  been  salivated,  and  the  manu- 
facturer has  sustained  considerable  loss 

To  preserve  a  principal  part  of  the 
mercury  thus  dissipated,  and  to  prevent, 
in  a  great  measure,  the  terrible  effects  of 
it  on  the  constitution  of  the  operator,  is 
the  object  of  these  remarks,  as  far  as  it 
regards  manufacturers. 

By  means  of  an  apparatus  similar  to  the 
plan  delineated  in  the  figure,  which  has 
been  partially  and  successfully  adopted  by 
Mr.  Mark  Sanders,  an  eminent  button- 
maker  of  Birmingham,  the  principal  part 
of  the  mercury  may  be  recovered,  and  the 
health  of  the'operator  greatly  preserved. 

A  hearth  of  the  usual  height  is  to  be 
erected,  in  the  middle  of  which  a  capacity 
for  the  lire  is  to  be  made  ;  but  instead  of 
permitting  the  smoke  to  ascend  into  the 
top  A,  made  of  sheet  or  cast  iron,  through 
which  the  mercury  is  volatilised,  a  flue 
for  that  purpose  should  be  conducted 
backwards  to  the  chimney  B  An  iron 
plate,  thick  enough  to  contain  heat  suffi- 
cient to  volatilise  the  mercury,  is  to  cover 
the  fire-place  at  the  top  of  the  hearth  C. 
There  must  be  an  ash-hoie,  D,  under  the 
fire-place.  The  square  space  E,  seen  in 
the  fire-place,  is  the  fine,  which  serves  to 


carry  the  smoke  back  under  the  hearth  in- 
to the  chimney  B.  The  door  of  the  fire- 
place and  ash-pit  may  either  be  in  front, 
as  represented  in  the  figure,  or  at  the  end 
of  the  hearth  at  F,  which  will  perhaps 
less  incommode  the  work-people.  It  would 
be  of  great  advantage  if  the  space  be- 
tween A  and  the  iron  plate  C  was  cover- 
ed up  with  a  glass  window  coming  down 
so  low  as  only  to  leave  sufficient  room  for 
moving  the  pan  backwards  and  forwards 
with  facility.  If  the  sides  were  also  glass 
instead  of  brick-work  it  would  be  still 
better,  as  the  work-people  would  be  able 
to  have  a  full  view  of  their  work  without 
being  exposed  to  the  fumes  of  the  mer- 
cury, when  volatilised  by  heat  communi- 
cated to  the  pan  by  the  heated  iron  plate 
over  the  fire-place,  would  ascend  into  the 
top  A,  appropriated  for  its  reception,  and 
descend  into  the  tub  G,  covered  at  top 
and  filled  pretty  high  with  water.  By  this 
means  the  hearth  would,  in  fact,  become 
a  distilling  apparatus  for  condensing  and 
recovering  the  volatilised  mercury.  In 
the  tub  G  the  principal  part  would  be  re- 
covered ;  for,  of  what  may  still  pass  on,  a 
part  would  be  condensed  in  ascending  the 
tube  H,  and  fall  back,  while  the  remainder 
would  be  effectually  caught  in  the  tub  or 
cask  I,  open  at  the  top  and  partly  filled 
with  M  ater.  The  latter  tub  should  be  on 
the  outside  of  the  building,  and  the  de- 
scending branch  of  the  tube  H  should  go 
down  into  it  at  least  18  inches,  but  not  in- 
to the  water.  The  chimney  or  the  ash- 
pit should  be  furnished  with  a  damper,  to 
regulate  the  heat  of  the  fire. 

The  water  may  be  occasionally  drawn 
out  of  the  tubs  by  a  siphon,  and  the  met- 


MAN 


MAN 


-ury  clogged  with  heterogeneous  matter 
may  be  triturated  in  a  piece  of  flannel  till 
it  passes  through,  or  placed  in  a  pan  of 
sheet  iron,  like  a  dripping-pan,  in  a  suffi- 
cient  degree  of  heat,  giving  it  a  tolerable 
inclination,  so  that  the  mercury,  as  it  gets 
warm,  may  run  down  and  unite  in  the 
lower  part  of  the  pan.  But  the  mercury 
will  be  most  effectually  recovered  by  ex- 
posing the  residuum  left  in  the  flannel  bag 
to  distillation  in  a  retort  made  of  iron  or 
of  earthenware. 

When  the  mercury  is  volatilised  from 
the  buttons,  or,  as  the  workmen  denomi- 
nate it,  when  the  buttons  are  dried  off, 
they  are  finally  burnished,  and  are  then 
finished  and  fit  for  carding. 

The  reader  unacquainted  with  this 
branch  of  manufacture  will  be  surprised 
to  learn  how  far  a  small  quantity  of  gold, 
incorporated  with  mercury,  will  spread 
over  a  smooth  surface  of  copper.  Five 
grains,  worth  one  shilling  and  threepence, 
on  the  top  of  a  gross,  that  is,  144  buttons, 
each  of  one  inch  diameter,  are  sufficient 
to  excuse  the  manufacturer  from  the  pen- 
alty inflicted  by  an  act  ofthe  British  parlia- 
ment; yet  many,  upon  an  assay,  are  found 
to  be  deficient  ot  this  small  quantity,  and 
the  maker  fined,  and  the  buttons  forfeited 
accordingly.  Many  hundred  grosses  have 
been  tolerably  gilt  with  half  that  quanti- 
ty ;  so  extremely  far  can  gold  be  spread, 
when  incorporated  with  mercury,  over  the 
surface  of  a  smooth  piece  of  copper.  See 
Gilding. 

Manufacture  of  Cat-gut. — If  the  intes- 
tines of  sheep  and  lambs  be  first  cleansed, 
and  then  dried  and  twisted  together, 
either  singly  or  several  together,  cat-gut 
will  be  made.  The  manufacture  of  this 
article  is  exceedingly  simple ;  the  princi- 
pal object  is  having  a  good  gut,  uniformi- 
ty in  the  twisting,  and  caution  in  drying-. 
Owing  to  the  great  consumption  of  this 
article  by  violin-makers,  watch-makers, 
hatters,  cutlers,  turners,  Sic.  it  is  always 
in  demand.  Some  time  since  a  consider- 
able manufactory  was  established  in  this 
city.  The  turner  instead  of  using  cat-gut 
with  the  lathe,  employ  the  hide  of  horses 
or  cows,  which  they  soak  and  cut  into 
strings ;  after  twisting  which,  they  dry 
them.  The  firmness  of  these  strings  is 
owing  to  the  gelatin  contained  in  the  skin. 

Another  use  of  cat-gut  ib  for  the  con- 
struction of  hygrometers  :  the  gut  will 
contract  in  dry  weather,  and  extend  as 
the  air  becomes  moist,  and  the  difference 
may  be  readily  shown. 

Manufacture  of  Calico.  See  Printing. 

Manufacture  of  Camphor,  refining.  See 
Camphor 

Manufacture  of  Cheese.  Sec  Cheese. 


Manufacture  of  Cloth.— Cloth,  in  com  - 
merce,  in  its  general  sense,  includes  all 
kinds  of  stuffs  woven  or  manufactured  on 
the  loom,  whether  their  threads  be  of 
wool,  cotton,  hemp,  or  flax. 

The  term  cloth  is,  however,  more  par- 
ticularly applied  to  the  web  or  tissue  of 
woollen  threads  interwoven,  whereof  some 
called  the  warp  arc  extended  lengthwise 
from  one  end  of  the  piece  to  the  other, 
the  rest,  called  the  woof,  are  disposed 
across  the  first,  or  breadthwise  of  the 
piece. 

The  manufacture  of  this  important  arti- 
cle naturally  divides  itself  into  several 
branches.  The  first  and  most  important 
of  which,  seems  to  be  a  judicious  choice 
ot  the  wool,  since  no  process  can  remedy 
a  defect  in  that  article.  It  is  therefore  of 
primary  importance  that  the  artist  should 
make  himself  well  acquainted  with  the 
different  kinds  of  wool  and  their  quali- 
ties. 

When  a  manufacturer  is  about  to  pur- 
chase of  this  article,  care  should  be  taken 
to  examine  well  the  body  ;  that  is  to  say, 
the  strength  and  fineness,  and  to  see,  by- 
separating  it  with  the  hands,  that  it  has  a 
proper  degree  of  softness,  that  it  is  not 
too  greasy,  and  above  all,  that  it  does 
not  consist  of  different  qualities  of  wool 
mixed  together. 

The  French  name  three  modes  which 
may  be  considered  in  a  general  M  ay  as  the 
best  by  which  to  ascertain  the  quality 
of  wool,  namely,  inspection,  smell  and 
sound. 

By  inspection  a  very  little  practice  will 
enable  us  to  determine"  its  relative  fineness, 
softness,  and  length  of  staple  ;  and  to  see 
that  it  be  clean  and  not  scabby  ;  and  hav- 
ing acquired  by  such  practice  a  better 
knowledge  of  the  article,  we  shall  soon 
be  enabled  to  judge  if  it  comes  from  the 
same  flock  of  sheep  without  any  mixture 
of  the  wool  from  an  inferior  one,  or  from 
lambs. 

Among  the  Spanish  wool  imported  into 
the  French  market,  there  are  bales  con- 
sisting of  well  shorn  fleeces  of  fresh  wool, 
free  from  all  kinds  of  admixture  or  dirt. 
These  are  called  Cavalieres,  and  are  in 
the  highest  estimation.  They  also  prefer 
wool  which  has  a  little  of  a  reddish  cast, 
and  the  more  it  swells  when  drawn  from 
the  bale  or  sack  in  which  it  has  been  com- 
pressed, the  better  is  the  quality.  By  the 
smell  may  be  discovered  the  freshness  of 
the  article,  if  it  be  all  new,  or  mixed  with 
old  wool.  If  it  smell  of  the  yoke,  the 
odour  will  be  fresh,  and  then  it  is  consi- 
dered new  ;  but  if  it  have  a  stale,  greasy 
smell,  it  is  then  the  wool  of  several  years, 
mixed,   Although  it  is  said  by  some  that 


MAN 


MAN 


good  wool  may  be  preserved  raw,  many 
vears  experience  has  taught  manufactur- 
ers that  wool  never  works  to  so  much  ad- 
vantage as  when  perfectly  fresh. 

The  grease,  or  yoke,  as  it  is  called,  is  a 
kind  of  fat  or  oil  adhering  to  the  wool, 
which  arises  from  the  perspiration  of  the 
sheep,  as  well  when  pastured  as  when  fed 
in  the  fold.  When  sheep  are  too  much 
confined  in  this  latter  place,  the  yoke  ad- 
heres too  much  to  the  wool,  and  injures 
its  quality  by  the  great  waste  which  it  oc- 
casions. 

By  our  sense  of  hearing  wre  may  form  a 
judgment  whether  the  wool  be  new  or 
old,  for  if  we  take  a  small  handful  and 
put  it  to  the  ear,  rubbing  it  between  the 
thumb  and  fore -fingers,  and  then  draw  it 
out,  shaking  it,  at  the  same  time,  if  it 
give  a  sharp  sound,  it  is  dry  and  light,  and 
is  certainly  old  j  but  if  it  give  a  soft  sound 
it  is  the  wool  of  the  season.  In  this  mode 
of  judging,  Mr.  Rousseau  cautions  us  to 
be  careful  to  distinguish  between  the  soft- 
ness caused  by  the  exposing  the  wool  to 
the  operation  of  steam,  which  produces 
an  effect  on  old  wool,  to  make  it  not  easily 
distinguishable  from  the  wool  of  the  sea- 
son. 

The  most  perfect  mode  to  ascertain  the 
quality  of  wool  by  sample,  is  to  subject 
it  to  the  several  operations  of  washing, 
beating,  and  picking;  these  different  ma- 
nipulations will  shew  what  may  be  expect- 
ed when  the  article  shall  be  worked  up, 
and  are  rendered  necessary  from  the  very- 
great  waste  which  attends  the  working  of 
some  wools,  which,  although  they  may 
be  of  a  very  good  quality,  will  produce 
great  loss  to  the  manufacturer,  whose  in- 
terest will  be  found  to  consist  in  never  at- 
tempting the  manufacture  of  ordinary 
wool. 

Of  the  Washing. — In  Spain  the  wool  of 
the  merino  sheep  is  scoured  after  it  is 
shorn  ;  and  by  skilful  shepherds,  the  mode 
of  Washing  the  wool  on  the  sheep's  back 
is  condemned,  because  dangerous  to  this 
animal,  and  really  of  trifling  advantage  to 
merino  wool,  the  thick  yoke  of  which  can 
be  but  in  a  small  degree  discharged  by 
ablution  in  cold  water  ;  nor  is  the  trouble 
to  the  artist  much,  if  any,  less,  as  the  wool 
will  have  to  go  through  another  thorough 
washing  before  it  can  be  manufactured. 

There  is,  we  think,  risk  in  a  general 


way  in  the  washing  of  wool  on  the  back 
of  the  sheep,  particularly  if  they  be  ex- 
posed to  severe  cold  and  rain.  Many  sheep 
have  fallen  a  sacrifice  to  the  cold  of  this 
climate,  but  this  may  be  attributable  per- 
haps with  good  cause  to  the  improper  pri- 
vation of  their  warm  clothing  and  conse- 
quent exposure  at  an  inclement  season  of 
the  year.  From  the  twentieth  of  May  to 
the  latter  end  of  June  is  considered  the 
proper  season  for  washing  the  merino 
sheep,  having  a  regard  always  to  the  tem- 
perature of  the  weather,  and  choosing  it 
as  much  as  possible  when  pleasant  and 
dry ;  with  this  precaution  the  washer 
should  stand  in  a  running  stream  of  suffi- 
cient depth  to  be  up  to  his  waist,  plunging 
the  sheep  repeatedly  into  the  stream,  ami 
rubbing  the  wool  well  with  the  water ;  and 
when  in  his  opinion  the  wool  is  as  clean  as 
it  can  be  made  by  this  process,  the  water 
should  be  well  squeezed  out  of  it,  begin- 
ning with  the  head  of  the  animal  and  pro- 
ceeding to  the  extremities. 

If  this  plan  be  pursued  with  due  atten- 
tion to  the  weather,  it  is  presumed  the 
risk  is  not  great,  yet  we  only  give  it  as  the 
mode  most  likely  "to  accomplish  the  object 
of  washing  the  wool  on  the  back  of  the 
sheep  without  the  usual  bad  consequen- 
ces, not  wishing  to  encourage  the  prac- 
tice too  much,  or  to  forbid  it  altogether. 

When  the  above  plan  has  been  adopted 
it  will  be  necessary  to  see  that  the  sheep 
are  kept  for  a  few  days  immediately  there 
after  in  a  clean  pasture,  that  the  wool  may 
become  dry,  and  that  the  yoke  may  rise 
again,  which  will  render  the  fleece  more 
soft  and  pliable.  Mr.  Bakewell  recom- 
mends a  plan  adopted  by  some  merino 
breeders  in  Sweden  of  placing  the  animal 
on  his  back  with  his  head  up  in  a  large 
tub,  washing  him  well  with  a  mixture  of 
warm  water  and  a  small  quantity  of  stale 
urine  or  soap  leys,  and  then  to  clean  him 
well  in  pure  water.  Mr.  B.  says  this  plan 
will  render  Spanish  wool  seven  per  cent, 
cleaner  than  cold  water,  and  with  much 
less  risk  of  felting  it  than  if  so  washed  af- 
ter being  shorn. 

The  following  figure  shews  the  mode 
of  assorting  wool  in  Spain,  into  four  dif- 
ferent qualities.  When  thus  assorted  they 
are  packed  for  the  market — A.  No.  1,  or 
Rafina  ;  B.  No.  2,  or  Fina ;  C.  No.  3,  or 
Tercera  ;  D.  No.  4,  or  Kahida. 


MAN 


MAN 


If  it  be  necessary  to  do  this  at  all,  the 
time  of  shearing  appears  certainly  best 
adapted  to  it,  but  as  we  have  never  heard 
that  any  other  nation  have  adopted  it,  we 
have  given  it  here  only  as  matter  of  infor- 
mation, leaving-  it  to  those  more  imme- 
diately interested  to  decide  if  it  have  any 
advantage  over  the  common  plan  of  as- 
sorting the  wool  by  the  manufacturer. 

All  mixture  of  wools  of  different  grades 
or  mixed  flocks  should  be  studiously 
avoided,  as  tending  very  much  to  lessen 
their  respective  value. 

With  these  observations  on  the  modes 
of  preparing  the  wool  we  now  proceed  to 
give  the  best  account  we  have  been  ena- 
bled to  obtain  of  the  manufacture  of  su- 
perfine cloth  in  Wiltshire,  England. 

It  is  previously  to  be  observed,  that  all 
the  cloths  which  are  designed  for  scarlets, 
greens,  and  blacks,  as  well  a9  many  of 
the  most  lively  and  delicate  colours,  are 
manufactured  white,  and  dyed  in  the 
piece  afler  they  are  finished. 

The  wool,  being  taken  out  of  the  bale, 
must  first  be  picked,  to  clear  it  from  the 
pitch  which  adheres  to  it,  and  from  the 
other  extraneous  substances  with  which 
it  abounds.  It  must  then  be  scoured,  by 
putting  it  into  a  furnace  containing  a  li- 
quor composed  of  three  parts  of  water 
and  one  of  urine.  After  it  has  been  well 
stirred  about  therein,  and  the  grease  it 
contains  dissolved,  it  must  be  taken  out, 
drained,  and  washed  in  running  water, 
and  in  that  state  it  is  fit  to  be  committed 
to  the  dye-furnace.  See  Dyeing. 

After  dyeing  it  must  be  again  washed 
and  well- dried,  when  it  must  be  beaten 
w  ith  rods  on  wooden  hurdles,  to  free  it 


from  the  dye-stuff,  which  still  hangs  about 
it ;  or  else  the  same  effect  is  produced  by 
putting  it  into  a  wool  mill,  formed  of  a 
four-flapped  vane  or  fan  thinly  set  with 
iron  spikes,  and  swiftly  revolving  within 
a  hollow  cylinder,  composed  of  small 
wooden  rods  or  staves,  sufficiently  wide 
apart  to  suffer  the  dust  to  fall  through,  as 
the  wool  becomes  slightly  separated  by 
the  motion  of  the  fans.  It  is  then  once 
more  carefully  picked,  in  order  to  take 
out  the  locks  which  are  unevenly  dyed, 
and  also  the  lint,  and  other  filth  with 
which  wool  in  this  state  generally 
abounds. 

In  making  mixed  cloths,  wool  of  the 
different  colours,  being  weighed  out  in 
their  requisite  proportions,  are  first  sha- 
ken well  together ;  they  are  then  further 
mixed  by  being  well  turned  in  the  wool 
mill,  and  by  being  afterwards  twice  pass- 
ed through  the  scribbling  engine  instead 
of  once,  they  are  generally  found  to  be 
sufficiently  intermixed. 

The  wool,  thus  prepared,  must  now  be 
spread  abroad  on  a  floor,  and  oil  of  olives 
(in  the  proportion  of  31b.  to  201b.  of  wool) 
evenly  sprinkled  over  it,  and  beat  into  it 
with  heavy  rods,  when  it  is  in  a  proper 
state  to  be  carried  to  the  scribbling  en- 

This  is  a  machine  composed  of  ten  or 
more  wooden  cylinders,  of  various  sizes, 
covered  with  cards,  the  teeth  or  wire  of 
which  are  of  different  degrees  of  fineness, 
and  bent  or  hooked  in  opposite  directions. 
These  are  combined  in  a  strong  wooden 
frame,  and  so  fitted  as  just  to  touch  and 
work  against  each  other,  as  they  swiftly 
revolve  on  being  set  in  motion  by  a  com- 


MAN 


MAN 


mon  handle,  adapted  to  be  turned  either 
by  men's  labour,  or  any  sort  of  mill  work. 
By  passing  through  this  engine,  the  locks 
of  wool,  which  before  were  close  and 
matted  together,  are  drawn  abroad,  the 
fibres  are  separated,  and  it  is  formed  into 
light  flakes  ;  it  is  then  taken  to  the  carder, 
which  is  a  smaller  engine  of  the  same  kind, 
only  covered  with  finer  cards,  and  with 
the  addition  of  a  fluted  roller  revolving  in 
a  trough  at  the  tail  of  the  machine ;  by 
which  the  wool,  after  being  still  finer  and 
better  mixed  and  carded,  is  formed,  as  it 
drops  out,  into  separate  and  smooth  rolls, 
of  28  inches  long,  and  half  an  inch  in 
thickness,  which  are  immediately  taken 
by  boys,  and  joined  or  attached  to  the 
spindles  of  the  roving  or  slubbing  ma- 
chine. 

This  is  a  contrivance,  by  which  50  or 
more  iron  spindles,  being  set  upright  in  a 
wooden  frame,  are  twirled  by  one  motion, 
yielding  their  threads  to  a  common  slider, 
at  every  move  of  which  the  50  rolls  of 
wool  are  drawn  out  and  formed  into  as 
many  large  slightly  twisted  threads,  and 
at  the  same  time  wound  off  into  balls  of 
a  size  and  shape  adapted  to  the  next  ope- 
ration, or  spinning. 

This  is  performed  by  a  machine  called 
the  spinning  jenny,  which  also  is  a  frame 
containing  70  or  more  upright  spindles, 
twirled  like  the  former  by  a  common  mo- 
tion, and  yielding  their  threads  to  one  and 
the  same  slider ;  by  this  the  large  hollow 
threads  are  further  twisted  and  drawn  out 
to  the  degrees  of  smallness  and  strength 
requisite  for  the  different  purposes  for 
which  they  are  designed.  The  threads, 
being  thus  spun,  are  reeled  into  skains 
and  prepared  for  the  loom.  The  larger 
sort,  destined  for  the  woof,  are  wound  on 
spools,  which  are  small  tubes,  so  formed 
as  to  be  easily  placed  in  the  eye  or  hollow 
of  the  shuttle".  That  for  the  warp  is  wound 
on  large  wooden  bobbins,  from  which,  by 
the  warping  bar,  it  is  conveniently  formed 
into  the  proper  lengths  and  divisions,  and 
so  arranged  and  disposed  as  to  form  the 
chain  or  warp  of  the  piece. 

The  chain,  thus  prepared,  must  be  stif- 
fened by  a  size,  which  is  made  by  dissolv- 
ing 3  lbs.  of  glue  (the  best  sort  of  which 
is  made  from  shreds  of  parchment)  in  a 
quantity  of  water  sufficient  to  moisten  and 
saturate,  the  whole,  and  when  dried  it  is 
ready  to  be  turned  on  the  loom. 

In  weaving  broad-cloth  there  are  two 
weavers  in  a  loom,  one  on  each  side,  who  i 
at  the  same  time  tread  alternately  on  the 
same  treadle,  i.  e.  now  on  the  right  side 
and  now  on  the  left,  which  raises  and  i 
lowers  the  threads  of  the  warp  equally, 
between  which  they  throw,  transversely,  I 


■  the  shuttle  from  the  one  to  the  other.  A: 
each  time  that  the  shuttle  is  thrown  (and 
so  a  thread  of  the  woof  inserted  within 
the  warp),  they  strike  it  conjointly  with  a 
moving  frame,  wherein  is  fastened  the 
slay,  which  is  a  kind  of  comb,  composed 
of  thin  pieces  of  cane,  between  whose 
teeth  the  threads  of  the  warp  are  passed, 
repeating  the  strokes  six  or  seven  times 
with  the  warp  open,  and  again  as  many 
times  after  it  has  crossed  and  closed  on 
the  woof.  The  whole  warp  being  filled 
with  woof,  the  cloth  is  finished. 

Being  next  taken  to  the  fulling-mill,  it 
is  there  soaked  with  urine  or  hog's  dung, 
and  afterwards  scoured  with  clean  water ; 
it  is  thus  freed  from  the  oil  and  filth  con- 
tracted in  dyeing,  and  delivered  perfectly 
clean,  in  a  state  fit  for  the  next  operation, 
which  is  burling. 

By  this  process  (performed  by  women 
with  little  iron  nippers)  the  cloth  is  clear- 
ed from  all  the  knots,  lint,  small  straws, 
and  lesser  filth  ;  and  if,  by  the  careless- 
ness of  the  spinner  it  contains  any  large 
uneven  threads,  they  must  now  be  gently 
taken  out;  and  if  any  small  hole  or  rent 
is  made,  it  must  be  carefully  drawn  up, 
and  mended  with  some  of  the  warp-yarn 
of  the  same  cloth. 

Butthat  compactness  and  density  which 
distinguish  woollen  cloth  from  ail  other 
manufactures,  and  renders  it  so  peculiar- 
ly adapted  to  our  wear  in  these  northern 
climates,  is  derived  from  the  next  ope- 
ration, which  is  fulling,  or  milling,  by 
which  a  cloth  of  40  yards  long,  and  100 
inches  wide,  being  first  sprinkled  over 
with  a  liquor  prepared  from  5  lbs.  of  fine 
soap  (made  from  the  oil  of  olives)  dis- 
solved in  hot  water,  is  laid  in  the  mill, 
trough,  and  there  pounded  or  stamped  on 
by  two  heavy  wooden  hammers,  alternate 
lv  raised  and  depressed  by  the  cogs  of  a 
mill-wheel.  By  this  process  it  becomes 
by  degrees  (generally  in  about  8  hours) 
so  thickened  and  shrunk  up,  as  to  be  re- 
duced to  30  yards  long  and  60  inches  wide, 
which  renders  it  of  the  proper  substance 
and  thickness  of  common  superfine  cloth. 
During  this  operation,  it  must  be  taken 
out  from  the  trough  from  time  to  time,  to 
have  more  soap  added,  and  to  be  smooth- 
ed from  the  wrinkles  and  creases  which  it 
would  otherwise  contract. 

This  faculty  of  being  rendered  thicker 
by  compression,  is  peculiar  to  woollen  sub- 
stances. In  vain  may  fabrics  of  silk  or 
cotton  be  subjected  to  the  same  process  . 
they  would  not,  in  any  length  of  time,  be 
rendered  thicker  by  it,  or  more  compact 
in  the  smallest  degree.  To  account  for 
this,  it  has  been  observed,  that  the  single 
hairs  of  wool,  when  viewed  in  a  micrr  - 


MAN 


MAN 


scope,  are  discovered  to  be  thickly  set 
with  rough  and  jagged  protuberances, 
adapted  to  catch  and  entangle  with  each 
other.  Whence  it  seems  probable,  that 
during  the  violent  agitation  the  cloth  un- 
dergoes in  the  mill-trough,  the  fibres  be- 
ing, at  every  stroke  of  the  mill-hammer, 
strongly  impelled  together,  and  driven 
into  the  closest  possible  contact,  at  length 
hook  into  each  other,  drawing  closer  and 
closer  as  the  process  continues,  till  they 
become  thus  firmly  and  inextricably  uni- 
ted ;  each  thread,  both  of  the  warp  and 
the  woof,  being  so  joined  and  compacted 
with  those  that  are  contiguous  to  it,  that 
the  whole  seems  formed  into  one  substance, 
not  being  liable,  like  other  fabrics,  when 
cut  with  shears,  to  unravel  and  become 
ragged  at  the  edges. 

The  cloth,  thus  milled  to  its  proper 
thickness,  must  be  scoured  with  clean 
water  till  it  be  perfectly  free  from  the  soap. 
In  this  part  of  the  process,  a  preparation 
of  fullers-earth  and  bullock  s  gall  is  found 
very  serviceable,  rendering  the  cloth  at  the 
same  time  soft  and  mellow. 

The  cloth  must  now  be  taken  to  the 
cloth-worker,  in  order  to  be  dressed  ; 
which  is  performed  by  first  properly  draw- 
ing out,  and  arranging  in  one  direction, 
all  the  hairs  or  fibres  of  the  wool  that  can 
possibly  be  brought  to  the  surface,  and 
then  shearing  it  as  close  as  it  will  admit, 
without  discovering  the  ground  of  the 
cloth,  or  laying  the  threads  bare. 

The  instruments  employed  in  this  ope- 
ration, are  the  wire  cards,  and  teasils,  to 
raise  and  draw  out  the  hair,  and  the  shears 
to  cut  off  what  is  too  long  and  superflu- 
ous. The  teasil  is  a  large  kind  of  this- 
tle, with  the  points  growing  very  strong 
and  hooked  ;  to  use  them  the  heads  are 
cut  off,  and  set  close  together  in  small 
wooden  frames  called  handles.  These 
instruments,  although  hitherto  worked  by 
men's  hands,  with  great  labour  and  ex- 
pense, have  of  late  been  so  ingeniously 
adapted  to  machinery  turned  by  mill- 
wheels,  as  to  perform  the  same  operation, 
with  much  more  preciseness  and  effect, 
as  well  as  great  saving  in  point  of  expense, 
and  the  machines  for  this  purpose  are  va- 
rious, and  continually  improving.  The 
method  hitherto  employed  is  generally  as 
follows. 

The  cloth  being  drawn  over  a  frame, 
constructed  of  boards  laid  sloping,  and 
covered  with  hair-cloth,  is,  during  its 
passage,  in  order  to  raise  the  wool,  regu- 
larly scraped,  or  rubbed,  from  one  end  to 
the  other,  with  the  cards  or  teasils,  be- 
ing all  the  time  kept  as  wet  as  possible  by 
continually  pouring  water  upon  it.  It  is 
then  laid  on  the  shearing  boards,  which 
VOt.  II. 


are  made  of  wooden  planks  covered  with 
coarse  cloth,  and  forming  a  kind  of  hard 
cushion,  where  the  wool  thus  raised  is  cut 
off  with  long  heavy  shears,  which  are 
pressed  close  to  the  cloth  with  leaden 
weights,  and  gradually  slide  forward  at 
every  motion  or  cut,  till  they  have  proceed- 
ed from  one  list  to  the  other.  The  cloth 
is  then  returned  to  be  again  scraped  or 
rubbed ;  these  operations  are  repeated 
three  times,  every  time  with  finer  cards, 
or  teasils,  when  the  wool  becomes  suffi- 
ciently raised.  It  must  now  be  taken  to 
the  rack,  on  which  being  fastened  by  the 
lists  with  small  hooks  or  tenters,  it  must 
be  drawn  or  strained  thereon,  until  it  be 
of  an  even  breadth  throughout ;  when  dry 
it  is  returned  to  the  shearing  boards,  on 
which  the  cutting  is  repeated  three  times 
more  on  the  right  side,  and  once  on  the 
other  or  back  side.  After  this  it  is  given 
to  the  cloth -drawers,  who,  having  first, 
with  small  picking-irons,  made  very  sharp 
at  the  points,  drawn  out  all  the  small 
straws  and  bits  of  lint  which  have  before 
escaped  notice,  carefully  fine-draw  or 
mend  the  small  holes  or  rents,  if  any  such 
have  been  made  in  it. 

Nothing  now  remains  to  be  done  but 
pressing  ;  preparatory  to  which,  the  cloth 
being  doubled  and  laid  in  even  folds,  a 
leafj  or  sheet  of  glazed  pasteboard,  is 
inserted  between  each  fold  or  plait  of  the 
cloth  ;  it  is  then  laid  in  the  press,  and  co- 
vered with  thin  wooden  boards  or  fences, 
on  which  are  laid  iron  plates  properly 
heated,  and  on  the  whole  (by  means  of  a 
lever  turning  a  screw)  the  top  of  the  press 
is  brought  down,  with  the  degree  of  force 
judged  necessary  to  give  it  the  proper 
gloss.  When  cold,  it  may  be  taken  out 
of  the  press,  in  order  to  be  folded  and 
packed,  ready  for  sale. 

Manufacture  of  Colours.  See  Colour- 
making. 

Manufacture  of  Copperas.  See  Cop- 
peras, Iron. 

Manufacture  oi'  Combs.— Combs  are  ge- 
nerally made  of  the  horns  of  bullocks,  or 
of  elephants'  and  sea-horses'  teeth  :  some 
are  made  of  tortoise-shell,  and  others  of 
box  or  holly  woods.  Bullocks'  horns  are 
thus  prepared  in  order  to  manufacture 
combs  :  the  tips  are  first  sawn  off :  they 
are  then  held  in  the  flame  of  a  wood  fire ; 
this  is  called  roasting,  by  which  they  be- 
come nearly  as  soft  as  leather.  While  in 
that  state  they  are  slit  open  on  one  side, 
and  pressed  in  a  machine  between  two 
iron  plates  ;  they  are  then  plunged  into  a 
trough  of  water,  from  which  they  come 
out  hard  and  flat 

The  comb-maker  now  saws  them  into 
lengths  according  to  the  sized  combs  he 
D 


MAN 


MAN 


wants.  To  cut  the  teeth,  each  piece  is  fixed 
in  a  tool  called  a  clam.  The  teeth  are  cut 
with  a  fine  saw,  or  rather  a  pair  of  saws,  and 
they  are  finished  with  a  file.  A  coarser 
file  called  a  rasp,  is  used  to  reduce  the 
horn  to  a  proper  thickness  ;  and  when  the 
combs  are  made,  they  are  polished  with 
charcoal  and  water,  and  receive  then-  last 
finish  with  powder  of  rotten -stone. 

The  process  used  for  making-  ivory' 
combs,  is  nearly  the  same  as  that  already 
described,  except  that  the  ivory  is  first 
sawed  into  thin  slices.  The  best  ivory 
comes  from  the  island  of  Ceylon  and 
Achen,  in  the  East  Indies,  since  it  has  the 
property  of  never  turning  yellow :  of 
course,the  ivory  from  these  places  is  much 
dearer  than  that  brought  from  other  parts. 

Having  described  the  usual  method  of 
making  combs,  it  is  right  to  inform  the 
reader,  that  about  eight  years  ago,  a  pa- 
tent was  obtained  for  cutting  combs  by 
means  of  machinery.  Mr.  Pettibone  also 
obtained  a  patent  for  a  similar  purpose  : 
it  was  carried  into  effect  in  Massachusetts. 
It  will  be  thought  a  very  singular  circum- 
stance, that,  before  this  period,  no  meth- 
od was  practised  for  cutting  the  teeth  of 
combs,  but  that  in  which  a  pair  of  saws, 
rudely  fastened  in  a  wooden  back,  was 
directed  by  the  human  hand.  With  these 
implements,  however,  it  is,  that  the  very 
delicate  superfine  ivory  combs,  containing 
from  fifty  to  sixty  teeth  in  an  inch,  are 
manufactured. 

By  the  machine  the  business  of  comb- 
making  is  greatly  expedited  ;  the  teeth  of 
two  combs  may  be  cut  in  about  three  mi. 
nutes.  The  combs  are  afterwards  pointed 
by  applying  them  to  an  arbor  or  axis 
clothed  with  cutters  having  chamfered 
edges  and  teeth.  See  11th  vol.  Repertory 
of  Arts,  for  a  description  of  this  machine. 

Tortoise-shell  combs  are  very  much 
used,  and  there  are  methods  of  staining 
horn  so  as  to  imitate  tortoise-shell ;  of 
which  the  following  is  one : — The  horn  \  o 
be  dyed  must  be  first  pressed  into  a  flat 
form,  and  then  spread  over  with  a  paste 
made  of  two  parts  of  quick-lime  and  one 
of  l'n.harge,  brought  into  a  proper  consist- 
ence with  soap-ley.  This  paste  must  be 
put  over  all  the  parts  of  the  horn,  except 
such  as  are  proper  to  be  left  transparent, 
to  give  it  a  nearer  resemblance  to  tortoise- 
shell  The  horn  must  remain  in  this  state 
till  the  paste  be  quite  dry,  when  it  is  to  be 
brushed  off.  It  requires  taste  and  judg- 
ment to  dispose  the  paste  in  such  a  man- 
ner as  to  form  a  variety  of  transparent 
parts,  of  different  magnitudes  and  figures, 
to  look  like  nature.  Some  parts  should 
also  be  semi-transparent ;  which  may  be 


[  effected  by  mixing  whiting  with  a  part  of 
i  the  paste,  to  weaken  its  operation  in  par- 
'  ticular  places  ;  by  this  means  spots  of  a 
reddish  brown  will  be  produced,  so  as 
greatly  to  increase  the  beauty  of  the  work. 
Horn  thus  dyed  is  manufactured  into 
combs,  and  these  are  frequently  sold  for 
real  tortoise-shell.  See-.HoRX. 

.Manufacture  of  Cotton  :  one  of  the  lead- 
ing and  most  important  branches  of  our 
national  industry.  On  arriving  at  the  cot- 
j  ton-mill  the  bags  are  unpacked,  and  the 
contents  examined,  at  the  same  time  it  is 
turned  over  and  beaten  with  a  stick,  and 
the  gross  impurities  picked  out  with  the 
fingers.  This  is  called  sorting,  and  the 
object  of  the  beating  is  to  soften  and  open 
the  fibre  of  the  cotton,  so  as  to  expose 
every  part.  The  sorting  is  performed  im- 
mediately when  the  bags  of  cotton  are 
opened,  but  it  has  still  to  undergo  a  se- 
cond examination,  called  picking;  the 
principal  object  of  the  first  examination, 
or  sorting,  being  intended  to  ascertain  the 
quality  of  the  cotton,  and  to  find  what 
kind  of  goods  it  is  best  adapted  for  manu- 
facturing, and  in  this  examination  the 
coarsest  impurities  and  yellow  damaged 
parts  are  picked  out. 

After  sorting  the  cotton,  it  is  carried  to 
the  batting  machine,  and  the  coarser  sorts 
of  cotton  to  the  opening  machine,  which 
is  known  to  the  workmen  by  the  name  of 
devil.  In  the  batting  machine,  the  cotton 
is  spread  upon  a  platform  of  ropes  strain- 
ed very  tight,  and  a  number  of  rods  strike 
very  smartly  upon  it,  by  which  they  open 
the  fibres  and  loosen  the  knots  of  cotton 
preparative  to  the  succeeding  operations  \ 
at  the  same  time  the  violence  of  the  bat- 
ting loosens  and  shakes  out  all  dirt,  dust, 
and  cotton  seeds,  of  which  the  cotton  in 
its  raw  state  contains  a  great  number,  and 
which  would  be  very  prejudicial  to  the 
operations  of  the  more  delicate  machines. 
The  cotton,  when  first  packed  up  in  the 
bags,  is  compressed  very  closely,  for  the 
convenience  of  stowage,  and  this  conden- 
ses it  into  a  hard  matted  mass  ;  but  the 
batting  machine,  striking  it  violently  with 
small  sticks,  causes  the  fibres,  by  their 
natural  elasticity,  and  the  motion  occa- 
sioned among  them,  to  gradually  loosen 
and  disengage  themselves,  and  the  cotton, 
by  repeated  strokes,  recovers  all  its  origi- 
nal volume. 

The  opening  machine  has  the  same  ob- 
jects, and  produces  the  same  effects, 
though  in  a  very  different  manner,  as  it 
consists  of  a  rapidly  revolving  cylinder, 
on  which  a  great  number  of  iron  teeth,  Of 
spikes  are  fixed;  which  tear  and  open  the 
cotton  against  other  similar  teeth.,  which 


MAN 


MAN 


are  fixed  in  a  stationary  half  cylinder  or 
hook,  enclosing"  the  other.  The  batting 
machine  is  used  for  the  finer  kind  of  cot- 
ton ;  and  the  opening  machine,  which  acts 
in  a  more  rapid  though  less  effective  man- 
ner, is  employed  upon  the  coarser  sorts. 
After  batting  or  opening,  the  cotton  is 
again  picked,  to  remove  those  finer  parti- 
cles of  dirt  which  were  before  enveloped 
in  the  cotton,  but  are  exposed  hy  the  ope- 
ration of  the  machine.  It  is  performed 
by  women,  who  remove  all  extraneous 
matter,  and  every  particle  of  yellow  or 
damaged  cotton.  The  perfection  of  the 
article  to  be  produced,  depends  in  a  great 
degree  on  the  care  with  which  the  picking 
is  performed,  and  this  is  almost  the  only 
process  in  the  cotton  spinning,  which  can- 
not be  performed  by  machinery,  because 
it  necessarily  requires  a  discretionary 
power. 

The  cotton  wool  being  picked  clean,  is 
next  mixed ;  that  is,  the  contents  of  differ- 
ent bags  are  mixed  together  with  a  view 
of  obtaining  a  similarity  in  the  quality  of 
the  cotton  which  is  to  be  spun.  In  this 
operation  the  greatest  art  of  cotton-spin- 
ning consists,  and  it  is  that  department  in 
which  experience  alone  guides  the  manu- 
facturer. By  a  judicious  mixture  of  dif- 
ferent sorts  of  cotton,  some  spinners  will 
produce  a  very  fine  and  capital  yarn,  from 
such  cotton  as  would,  if  spun  alone,  or 
improperly  mixed,  only  produce  coarse 
and  low  priced  goods.  The  mixture  is 
effected  by  making  a  pile  or  heap,  consist- 
ing of  successive  layers,  of  the  different 
kinds  of  cotton  which  are  to  be  mixed ; 
then  by  raking  away  a  small  quantity  at  a 
time  from  the  edges  of  the  heap,  striking 
the  rake  from  the  top  to  the  bottom, 
through  all  the  different  layers,  the  cotton 
will  be  very  equally  mixed.  Sometimes 
the  cotton  wool  is  dyed,  and  different  co- 
lours are  mixed  together.  It  is  now  spread 
out,  very  evenly  and  regularly,  upon  a 
long  cloth,  which  is  rolled  up  and  carried 
to  the 

Carding  machine. — This  consists  of  a 
number  of  cylinders,  covered  with  wire 
teeth  or  cards,  and  revolving  with  consi- 
derable velocity  in  opposite  directions, 
nearly  in  contact  with  each  other,  and 
covered  by  a  dome  also  lined  with  cards. 
The  cotton, being  introduced  among  these? 
is  continually  combed,  or  carded,  by  the 
teeth,  until  almost  every  individual  fibre 
is  separated  and  drawn  straight,  and  every 
little  knotty  and  entangled  part  disengag- 
ed. By  passing  gradually  through  the 
machine  from  one  cylinder  to  another,  the 
cotton  is  dispersed  lightly  and  evenly 
among  the  teeth  over  the  whole  surface  of 
the  last,  or  finishing  cylinder,  from  which 


it  is  detached  by  the  mechanism  in  a  con- 
tinued fleece.  This  is  drawn  off,  and 
lapped  upon  a  cylinder  turned  slowly 
round  by  the  machine,  until  the  tteece 
has  made  a  great  number  of  turns  upon 
the  cylinder :  it  is  then  broken  off,  by 
dividing  it  at  one  part,  so  that  it  forms  a 
fleece  called  a  lap,  which  is  the  length  of 
the  circumference  of  the  cylinder,  and 
consisting  of  fifteen  or  twenty  thicknesses ; 
by  which  admirable  contrivance  very 
great  regularity  is  obtained  in  the  thick- 
ness of  the  lap,  because  if  any  one  part  of 
the  fleece  produced  by  the  machine  is 
thinner  or  thicker  than  it  ought  to  be,  in 
consequence  of  any  irregularity  in  the 
spreading  of  the  cotton-wool  upon  the 
cloth,  previous  to  carding,  such  irregu- 
larity will  have  no  sensible  effect  upon  the 
ultimate  thickness  of  the  lap,  because  it 
is  composed  of  thirty  or  forty  strata,  and 
there  is  no  probability  that  the  inequalities 
of  these  several  strata  will  fall  beneath 
each  other,  but  every  chance  that  they 
will  be  equally  dispersed  through  the 
whole,  and  thus  correct  each  other.  The 
lap,  when  taken  off,  is  laid  flat  on  a  cloth, 
which,  with  it,  is  rolled  up  and  conveyed 
to  a  second  carding-machine,  called  the 
finishing  card,  while  the  first  is  called  the 
breaker.  In  this  second  card  it  undergoes 
a  similar  process  to  the  first,  but  instead 
of  the  fleece  being  received  on  a  cylinder, 
it  is  contracted  by  passing  through  a  fun- 
nel, in  which  the  fleece,  being  hemmed  in 
on  both  sides,  is  gradually  contracted  to  a 
thick  roll,  which  may  be  continued  to  any 
length  as  long  as  the  machine  is  supplied 
with  cotton.  This  roll  or  band  of  cotton 
is  drawn  off  between  two  rollers,  which 
compress  it  into  a  pretty  firm,  flat  ribband, 
about  two  inches  broad.  The  rollers  de- 
liver it  into  a  tin  can  placed  to  receive  it, 
and  in  this  it  is  removed  to  the 

Drawing  Frame. — This  machine  con- 
sists of  several  pairs  of  rollers,  between 
which  the  cotton  is  passed,  and  every 
successive  pair  it  is  drawn  through  moves, 
by  means  of  the  wheel-work,  with  a  great- 
er velocity  than  those  preceding  it,  so  as 
to  stretch  out  the  band  or  sliver  of  cotton, 
in  the  same  manner  as  it  would  be  drawn 
out,  if  one  part  of  the  sliver  were  held 
between  the  finger  and  thumb  of  one  hand, 
and  another  part,  at  an  inch  or  two  dis? 
tant,  being  held  in  the  other  hand.  Then, 
by  drawing  the  two  hands  asunder  to  the 
extent  of  four  inches,  it  is  evident  two  in- 
ches in  length  of  the  cotton  sliver  would 
be  extended  or  drawn  out  to  four  inches,, 
In  like  manner,  the  first  pair  of  rollers 
through  which  the  sliver  passes,  are 
pressed  together  with  a  sufficient  weight 
to  hold  the  cotton  firmly  between  them, 


MAN 


MAN, 


The  second  pah*  of  rollers  are  situated  at 
one  or  two  inches  distant,  and  are  made 
by  the  wheel-work  to  revolve  more  swiftly 
than  the  first  The  difference  of  velocity, 
however,  is  but  small,  though  the  conse- 
quence is,  that  the  sliver  will  he  lengthen- 
ed in  the  same  proportion  ;  for  the  second 
rollers  take  up  the  cotton  much  faster  than 
the  first  pair  will  deliver  it  out :  it  must* 
therefore,  be  either  forcibly  pulled  through 
between  the  first  rollers,  or  it  must  be 
stretched  a  little,  by  the  fibres  slipping 
among  each  other,  or  it  must  break.  When 
the  extension  is  small,  the  only  effect  of  it 
is  merely  to  begin  to  draw  the  fibres 
(which  are  at  present  lying-  in  every  pos- 
sible direction)  into  a  straight  and  paral- 
lel position,  which  is  most  favourable  for 
the  subsequent  extensions.  The  drawing 
frame  contains  a  third,  and  some  of  them 
a  fourth  pair  of  rollers,  by  which  the  sli- 
ver undergoes  a  second  or  third  draught ; 
but  the  combined  effect  of  all  these  draw- 
ings is  generally  to  extend  the  sliver  to 
four  times  the  length  it  was  when  first  put 
to  the  nuchine  But  as  this  would  reduce 
the  silver  to  one-fourth  of  the  size,  which 
is  no>'  intended  in  this  stage  of  the  process, 
four  ends  or  slivers  are  introduced  be- 
tween the  rollers  together,  and  being 
drawn  into  one,  which  is  four  times  the 
length,  it  will  of  course  be  of  the  same 
size  as  any  of  the  four  which  is  put  in. 
This  drawing  process  is  repeated  three  or 
four  times,  and  the  alteration  it  makes  in 
the  cotton  is  to  equalize  the  size  of  the 
sliver,  on  the  same  principle  as  before 
described  of  the  breaking  card,  viz.  by 
repeatedly  combining  four  together,  and 
drawing  them  into  one  :  it  also  disposes 
the  fibres  longitudinally  and  in  the  most 
perfect  state  of  parallelism.  The  opera- 
tion of  carding  effects  this  in  a  certain 
degree  ;  yet  the  fibres,  though  parallel, 
are  not  straight,  but  many  of  them  dou- 
bled, as  may  easily  be  supposed,  from  the 
teeth  of  the  cards  catching  the  fibres 
sometimes  in  the  middle,  which  become 
hooked  or  fastened  upon  them. 

Though  the  general  ar.  angement  of  the 
fibres  of  a  sliver  from  ihe  finishing  card 
is  longitudinal,  yet  the\  ai  t  doubled,  bent, 
and  interlaced  in  such  a  wa\ ,  as  to  render 
the  operation  we  are  now  speaking  of  ab- 
solutely necessary 

When  the  cardings  have  been  passed 
four  or  five  times  through  the  drawing 
frame,  every  fibre  is  stretched  out  at  full 
length,  and  disposed  in  the  most  even  and 
regular  direction  ;  so  that  each  fibre  will, 
when  twisted  into  a  thread,  take  its  pro- 
per  bearing,  in  consequence  of  every  one 
being  straightened  and  having  the  same 
tension. 


The  sliver  in  this  state  presents  a  most 
beautiful  appearance,  being  so  extremely 
regular  in  its  size,  and  all  the  fibres  drawn 
so  straight,  that  it  bears  a  fine  glossy  or 
silky  appearance.  It  is  upon  this  sliver 
or  ribband  of  cotton  wool  that  the  opera- 
tion of  spinning  begins.  The  general  ef- 
fect of  the  spinning  process  is,  to  draw 
out  this  massive  sliver,  and  to  twist  it  as 
it  is  drawn  out :  but  this  is  not  to  be  done 
by  the  fingers,  pulling  out  as  many  fibres 
of  the  cotton  at  once  as  are  necessary  for 
composing  a  thread  of  the  intended  fine- 
ness, and  continuing  this  manipulation  re- 
gularly across  the  whole  end  of  the  rib- 
band, and  thus,  as  it  were,  nibbling  the 
whole  of  it  away.  The  fingers  must  be 
directed  for  this  purpose  by  an  attentive 
eye  ;  but  in  performing  this  by  machinery, 
the  whole  ribband  must  be  drawn  out  to- 
gether and  twisted  as  it  is  drawn.  This 
requires  great  art  and  very  delicate  ma- 
nagement :  it  cannot  be  done  at  once,  that 
is,  the  cotton  roll  cannot  be  first  stretched 
or  drawn  out  to  the  length  that  is  ulti- 
mately produced,  from  the  tenth  of  an 
inch  of  the  sliver,  and  then  twisted  There 
is  not  cohesion  enough  for  this  purpose,  it 
would  only  break  off  a  bit  of  the  sliver,  and 
we  could  make  no  further  use  of  it ;  for 
the  fibres  of  cotton  are  very  little  impli- 
cated among  each  other  in  the  sliver,  be- 
cause the  operation  of  carding  and  draw- 
ing has  laid  them  all  parallel  in  the  sliver; 
and  though  compressed  a  little,  by  its 
contraction  in  the  card  from  a  fleece  of 
twenty  inches  to  a  ribband  of  two,  and 
afterwards  compressed  between  the  rol- 
lers of  the  drawing  frame,  yet  they  cohere 
so  slightly,  that  a  few  fibres  may  be  drawn 
out,  without  bringing  many  others  along 
with  them.  For  these  reasons,  the  whole 
thickness  and  breadth  of  two  or  three  in- 
ches are  stretched  to  a  very  minute  quan- 
tity, and  then  a  very  slight  degree  of 
twist  is  given  it,  viz.  about  two  or  three 
turns  in  the  inch,  so  that  it  shall  now  com* 
pose  an  extremely  soft  and  spungy  cyiin. 
der,  winch  cannot  be  called  a  thread  or 
corcl,  because  it  has  scarcely  any  firmness, 
and  is  merely  rounder  or  slenderer  than 
before,  busing  stretched  to  about  four 
times  the  former  length.  This  is  called 
roving,  and  the  operation  is  performed  in 
the 

Roving  Frame — This  machine  is  con- 
structed in  a  great  variety  of  forms,  but 
all  of  them  have  the  same  object  in  view, 
viz.  to  draw  out  the  sliver,  so  as  to  reduce 
it  from  a  large  band  to  a  coarse  and  loose 
thiead  ;  but  as  this  extension  would  ren- 
der it  so  extremely  tender,  that  it  would 
scarcely  hang  together  in  passing  through 
the  succeeding  machines,  the  roving 


MAtf 


MAN 


frame,  immediately  after  having-  drawn 
and  extended  it  to  the  intended  size  by 
rollers,  operating-  in  the  same  manner  as 
Hie  rollers  of  the  drawing  frame,  gives  it 
a  very  slight  twist,  as  before  mentioned, 
and  this  loose  thread,  which  is  called  the 
roving,  is  the  first  rudiment  of  a  thread. 
Although  it  is  extremely  tender,  and  will 
not  carry  a  weight  of  two  ounces,  it  is 
much  more  cohesive  than  before,  because 
the  twist,  given  to  it  makes  all  the  longi- 
tudinal fibres  bind  each  other  together, 
and  compress  those  which  lie  athwart  : 
therefore  it  will  require  twice  the  force  to 
pull  out  a  fibre  from  among  the  rest,  but 
still  not  near  enough  to  break  it.  In  draw- 
ing a  single  fibre  others  are  drawn  out 
along  with-it,  and  if  we  take  hold  of  the 
whole  assemblage  in  two  places,  about  an 
inch  or  two  asunder,  we  shall  find  that  we 
may  draw  it  to  near  twice  its  length,  with- 
out any  risk  of  its  separating  in  any  inter- 
mediate part,  or  becoming  much  smaller 
in  one  part  than  another.  It  seems  to 
yield  equally  over  all  parts. 

Our  readers  will  now  perceive,  that 
these  processes  will  ensure  all  that  is 
wanted,  and  prepare  a  roving  that  is  uni- 
form, soft,  and  still  very  extensible  :  in 
short,  fit  for  undergoing  the  last  treat- 
ment of  spinning,  by  which  it  is  made  a 
fine  and  firm  yarn. 

It  is  evident  that  the  roving-produced  by 
these  operations  must  be  exceedingly  uni- 
form The  uniformity  really  produced 
exceeds  all  expectation  ;  for  even  although 
there  be  some  small  inequalities  in  the 
carded  fleece,  yet  if  these  are  not  matted 
clots  which  the  card  could  not  equalize, 
but  only  consist  of  a  little  more  thickness 
of  cotton  in  some  places  than  m  others, 
this  inequality  will  first  be  diminished  by 
the  lapping  of  the  fleece  in  the  breaking 
card  ;  and  when  such  a  part  of  the  sliver 
comes  to  the  first  roller  of  the  drawing 
frame,  it  will  be  rather  more  stretched  by 
the  second  than  a  thin  part  would  be. 
That  this  may  be  done  with  greater  cer- 
tainty, the  weights  of  the  first  rollers  are 
made  very  small,  so  that  the  middle  part 
of  the  sliver  can  be  drawn  through,  while 
the  outer  parts  remain  fast  held. 

^  Such  is  the  state  of  the  roving-  as  pre- 
pared by  the  roving  frame.  All  the  pre- 
ceding processes  are  to  be  considered  as 
the  preparations :  and  the  operation  of 
spinning  is  not  yet  begun.  These  pre- 
parations are  the  most  tedious,  and  re- 
quire more  attendance  and  hand-labour 
than  any  subsequent  part  of  the  process- 
Tor  the  slivers  from  which  the  rovings 
are  made  are  so  light  and  bulky,  that  a 
lew  yards  only  can  be  piled  up  in  the  cans 
set  to  receive  them  from  the  carding  and 
drawing  :  a  person  must  therefore  attend 


and  watch  each  roller  of  the  drawing  and 
roving  frames,  to  join  fresh  slivers  as  they 
are  expended.  It  is  also  the  most  import- 
ant department  in  the  manufacture  ;  for 
as  every  inch  will  meet  with  precisely  the 
same  drawing  and  same  twisting  in  the 
subsequent  parts  of  the  process,  there- 
fore every  inequality  and  fault  of  the  sli- 
ver, indeed  of  the  fleece  as  it  quits  the 
finishing  card,  will  continue  through  the 
whole  manufacture,  in  a  greater  or  lesser 
degree;  being  only  diminished,  not  cor 
rected,  by  the  drawing,  doubling,  &c. 
The  spinning  of  cotton-yarn  now  divides 
itself  into  two  branches.  The  first  per- 
formed by  what  were  called  jennies,  when 
worked  by  the  hand,  but  since  they  are 
moved  by  the  power  of  a  mill,  they  are 
called  mules :  the  manner  of  action  resem- 
bles the  ancient  spinning  with  distaff  and 
spindle.  The  second  method,  called  spin- 
ning of  twist,  or  water-spinning,  because 
it  was  the  first  spinning  performed  by  a 
water-wheel,  is  in  imitation  of  the  spin- 
ning with  the  fly-wheel,  or  jack  and  flyer 
The  two  methods  differ  in  the  same  man-, 
ner,  as  the  old  wool  or  cotton-wheel  dif- 
fers from  the  spinning  with  the  flax  wheel. 
.Mr.  Arkwright's  chief  invention,  the  sub- 
stitution of  the  machinery  for  the  imme- 
diate work  of  the  human  finger,  was  at 
first  only  applied  to  the  manufacture  of 
twist,  or  water-spinning.  We  shall,  there- 
fore, first  direct  our  attention  to  this. 

The  water -spitining  process  is  little  more 
than  a  repetition  of  that  gone  through  in 
making  the  first  slivers  or  rovings,  which 
are  formed  on  bobbins,  either  by  the  rov- 
ing frame,  or  are  afterwards  bound  on 
bobbins  by  the  hand.  These  bobbins  are 
set  on  the  back  part  of  the 

Spinning-Jrame,  in  which  the  roving  is 
drawn,  and  extended  to  any  required  de- 
gree of  fineness ;  and  the  proper  twist 
being  given  to  it,  forms  it  to  the  required 
thread.  The  spinning-frame  is  provided 
with  systems  of  rollers,  in  the  manner  of 
the  drawing-frame,  through  which  the 
roving  passes,  and  is  drawn  out  accord- 
ing to  the  size  of  the  thread  which  is  re- 
quired to  be  spun,  which  varies  from  four 
to  seventeen  times  ;  and  it  is  then  twisted 
more  or  less,  as  the  thread  is  required  to 
be  hard  or  soft :  therefore,  the  spinning 
process  scarcely  differs  from  the  roving, 
except  in  the  twist  that  is  given  it,  after 
the  last  stretching,  in  its  length.  This 
is  much  greater  than  the  roving,  being  in- 
tended to  give  the  yarn  hardness  and 
firmness,  so  that  it  will  afterwards  break 
rather  than  stretch  any  more.  The  per- 
fection of  the  ultimate  thread  or  yarn  de- 
pends, in  a  great  measure,  on  the  ex- 
treme softness  of  the  roving ;  for  it  is  this 
only  which  makes  it  susceptible  of  an 


MAX 


MAN 


equable  stretching-,  all  the  fibres  yielding 
and  separating  alike  ;  and  this  property 
will  be  greatly  influenced  by  the  quantity 
of  twist  given  by  the  roving-frame.  For 
these  points  no  very  distinct  rule  can  be 
given :  it  varies  in  different  mills,  and 
with  different  species  of  cotton  wool,  as 
may  be  easily  imagined.  The  immediate 
mechanism,  or  manipulation,  must  be 
skilfully  accommodated  to  the  nature  of 
that  friction  which  the  fibres  of  cotton 
exert  on  each  other,  enabling  one  of  them 
to  pull  others  along  with  it.  This  is  great- 
ly aided  by  the  contorted  curled  form  of  a 
cotton  fibre,  and  a  considerable  degree 
of  elasticity  which  it  possesses.  In  this 
respect  it  greatly  resembles  woollen  fibres, 
and  differs  exceedingly  from  those  of  flax ; 
and  it  is  for  this  reason  that  it  is  so  ex- 
tremely difficult  to  spin  flax  in  this  way  : 
its  fibres  become  lank,  and  take  any  shape 
by  the  slightest  compression,  especially 
when  damp  in  the  slightest  degree.  But 
besides  this,  the  surface  of  a  cotton  fibre 
has  a  harshness  or  roughness,  which 
greatly  augments  their  mutual  friction. 
This  probably  is  the  reason  why  it  is  so 
unfit  for  tents,  and  other  dressings  for 
wounds,  and  is  refused  by  the  surgeons 
even  in  the  meanest  hospitals.  But  its 
harshness  and  elasticity  fit  it  admirably 
for  the  manufacture  of  yarn.  Even  the 
shortness  of  the  fibre  is  favourable  ;  and 
the  manufacture  would  be  very  difficult, 
if  the  fibre  were  thrice  as  long  as  it  gene- 
rally is.  If  it  be  just  so  long  that,  in  the 
finished  thread,  a  fibre  will  rather  break 
than  come  out  from  among  the  rest,  it  is 
plain  that  no  additional  length  can  make 
the  yarn  any  stronger,  with  the  same  de- 
gree of  compression  by  twining.  A  long 
fibre  will  indeed  give  the  same  firmness 
of  adherence,  with  a  smaller  compression 
by  twining.  This  would  be  an  advantage 
in  any  other  yarn  ;  but  in  cotton,  the  com- 
pression is  already  as  slight  as  can  be  al- 
lowed :  were  it  less,  it  would  become 
woolly  and  rough  by  the  smallest  usage  ; 
and  it  is  already  too  much  disposed  to 
teasle  out.  Now",  suppose  the  fibres  much 
longer,  some  of  thern  may  chance  to  be 
stretched  along  the  sliver  through  their 
whole  length.  If  the"  sliver  is  pulled  in 
opposite  directions,  by  pinching  it  at  each 
end  of  such  long  fibre,  it  is  plain  that  it 
will  not  stretch  till  this  fibre  be  broken 
up,  or  drawn  out ;  and  that  while  it  is  in 
its  extended  state,  it  is  acting  on  the  other 
fibres  in  a  very  unequable  manner,  accord- 
ing to  their  positions,  and  renders  the 
whole  apt  to  separate  and  draw  more  ir- 
regularly This  is  one  great  obstacle  to 
the  spinning  of  flax  by  similar  machinery. 
Mul$..spmning. — A  great  proportion  of 


the  cotton  is  spun  in  the  mule  instead  of 
the  water-frame.  The  preparation  it  un- 
dergoes for  either  method  is  the  same  ;  at 
leasx  the  processes  are  similar,  except 
that  the  quantities  of  draft,  and  some 
other  particulars,  may  be  varied  in  the 
preparation  of  the  cotton  which  is  to  be 
thus  spun  in  this  machine,  which  is  called 
a  mule,  either  because  it  is  a  kind  of  ma- 
chine which  might  easily  be  turned  by  a 
mule,  or  more  probably  because  it  is  a  sort 
of  mongrel,  partaking  of  the  nature  of 
both  drawing  and  spinning,  or  uniting  the 
action  of  both  the  roller  and  spindle.  It 
consists  of  three  sets  of  fluted  brass  roll- 
ers, the  flutes  of  which  turn  into  each 
other.  The  first  set  goes  faster  than  the 
second,  and  the  second  faster  than  the 
third  ;  between  which  when  the  sliver  of 
carded  cotton  enters,  it  is  a  little  length- 
ened out  between  the  first  and  second, 
and  farther  still  between  the  second  and 
third;  after  passing  which,  it  is  slightly 
twisted  by  the  rapid  circular  motion  of 
the  spindle-  This  has  the  same  effect  as 
the  spinning-frame ;  but  the  quantity  of 
draft  between  the  rollers,  or  extension  of 
the  sliver,  is  not,  like  the  water-frame,  to 
the  full  extent  which  the  thread  is  intend- 
ed to  be.  The  remainder  of  the  stretch- 
ing is  performed  in  this  manner ;  the  spin- 
dles of  the  mule,  which  give  the  twist  to 
the  thread,  are  fitted  in  a  frame,  so  that 
they  can  be  moved  backward  and  for- 
ward, in  a  straight  line,  to  and  from  the 
rollers  {  a  certain  length  of  the  roving  be- 
ing therefore  given  out  by  the  rollers,  the 
spindles  are  removed  backward  to  take  it 
up  as  fast  as  it  comes,  and  in  this  motion 
they  twist  it  slightly  :  at  the  same  time, 
but  after  a  certain  quantity  of  the  roving, 
a  yard  for  instance,  has  been  given  out  by 
the  rollers,  their  motion  ceases ;  but  the 
spindle  continues  to  recede  from  them, 
another  half  yard  for  instance,  continuing 
to  twist  the  thread  all  the  while.  By  these 
means,  it  is  evident  that  the  thread  will  be 
stretched  from  a  yard  to  a  yard  and  an  half 
in  length :  by  this  contrivance,  the  cotton 
will  bear  a  greater  degree  of  extension 
than  any  other,  because  it  is  constantly 
twisted  at  the  same  time  that  it  is  extend- 
ed in  length. 

The  invention  of  mules  forms  quite  an 
epoch  in  the  history  of  the  cotton  trade. 
A  vast  improvement  was  made,  about  35 
years  ago,  by  the  introduction  of  the  spin- 
ning jennies,  by  which  from  twenty  to  for- 
ty spindles  were  turned  at  a  time.  The 
spindles  were  the  same  as  the  mule,  and 
had  the  same  motion ;  but  this  machine 
was  not  provided  with  rollers  to  draw  out 
the  cotton,  previous  to  twisting,  merely 
depending  upon  the  stretching,  to  give  it 


MAN' 


MAN 


the  proper  extension  requisite  to  form  the 
roving  into  a  thread.  But  the  combina- 
tion of  the  jenny  with  sir  Richard  Ark- 
wright's  intention  of  drawing,  by  rollers, 
forms  a  method  superior  to  both,  at  least 
for  fine  goods.  The  method  of  stretch- 
ing gives  the  means,  as  we  have  before 
mentioned,  of  very  great  extension  ;  but 
if  this  be  carried  so  tar  as  to  draw  out  the 
coarse  loose  roving  to  a  fine  thread,  there 
will  be  great  danger  of  its  drawing  irregu- 
larly, that  is,  more  in  one  place  than  ano- 
ther. In  the  original  method  by  the 
jenny,  the  rovings  were  prepared  by  the 
hand-wheel :  they  were  loose,  coarse,  un- 
twisted threads,  partaking  somewhat  of 
the  nature  of  cardings,  though  approach- 
ing in  some  degree  to  spun  twist.  They 
were  obliged  to  be  prepared  by  the  hand- 
wheel,  because  the  cardings,  which  were 
prepared  by  hand-cards,  were  in  detached 
pieces  of  a  certain  length,  and  regularly 
tapering  towards  each  end :  the  joining 
of  these  together,  in  such  a  manner  as  to 
produce  an  equal  and  regular  roving,  re- 
quired a  care  and  attention  which  could 
not  be  effected  by  machinery. 

The  combination  of  sir  R.  Arkwright's 
system  of  preparation  with  the  jenny  pro- 
duced the  mule,  which,  without  the  de- 
fects of  its  original,  spins  in  the  most  ex- 
peditious and  perfect  manner.  The  ad- 
vantage of  this  mode  of  preparing  the 
threads  over  that  of  the  jenny  is,  that  the 
fibres  of  the  cotton  are  all  laid  longitudi- 
nally, and  nearly  in  as  small  number  as  is 
wanted,  before  they  are  begun  to  be  much 
twisted;  by  which  means,  threads  of  any 
required  fineness  are  made  much  stronger 
than  they  were  from  rovings,  made  upon 
the  spindle  of  the  hand-wheel  spun  in  the 
jenny,  which  twisted  them  too  much  in 
the  first  instance  ;  and  in  the  subsequent 
extension  or  stretching,  by  the  removal 
of  the  spindle,  for  rendering  them  finer, 
many  of  the  fibres  were  necessarily  bro- 
ken. On  one  of  these  mules  240  threads 
are  often  spun  at  once  ;  and  two  of  them 
may  be  managed  by  one  woman,  with  a 
child  to  tie  the  threads  which  may  occa- 
sionally break. 

The  reader  moderately  acquainted  with 
mechanics,  cannot  but  perceive,  that  by 
each  of  the  operations  now  described,  the 
colton-wool  is  prepared,  and  drawn  into  a 
fine  strong  thread  by  repeatedly  drawing 
the  sliver  till  its  fibres  become  straight, 
then  reducing  it  in  the  roving  frame  to  a 
coarse  thread,  and  by  a  slight  twist  giv- 
ing it  sufficient  strength  to  bear  such  an 
extension  as  will  reduce  it  to  the  size  in- 
tended, and  then  it  is  immediately  twist- 
ed into  a  hard  thread.  All  these  processes 
are  only  a  substitute  for  a  single  pull  of 


the  finger  and  thumb  of  the  spinner,  which 
she  accommodates  precisely  to  the  pecu- 
liar condition  of  the  lock  of  wool  which 
she  touches  at  the  moment :  she  can  fol- 
low this  through  all  its  irregularities,  and, 
perhaps,  no  two  succeeding  plucks  are 
alike.  But  when  we  cannot  give  this  mo- 
mentary attention  to  every  minute  portion, 
we  must  be  careful  to  introduce  the  rov- 
ing in  a  state  of  perfect  uniformity,  ;ind 
then  every  inch  being  treated  in  the  same 
manner,  the  final  result  will  be  equable, 
and  the  yarn  will  be  uniform. 

The  thread  being  now  finished,  either 
by  the  water-frame  or  mule,  it  is  carred 
to  the 

Heel,  by  which  it  is  taken  off  the  bob- 
bins of  the  spinning-frame,  or  the  cops  of 
the  mule,  and  formed  into  hanks.  The 
hank  is  a  measure  in  cotton  trade,  com- 
posed of  seven  leys,  each  of  120  yards  in 
length.  The  reel,  or  frame  round  which 
the  thread  is  wound  is  one  yard  and  a  half 
in  circumference,  and  at  every  80  turns 
(or  bouts)  which  it  makes,  the  80  turns  of 
the  thread  are  tied  together  to  keep  them 
separate,  and  this  measures  out  120  yards, 
which  is  called  a  ley,  but  the  thread  is  not 
cut  at  the  ley,  it  is  continued  to  be  wound 
on  the  reel,  till  seven  such  leys,  or  840 
yards,  are  reeled  :  it  is  then  cut  and  call- 
ed a  hank,  which  is  tied  up. 

The  different  sizes  of  cotton  yam,  or 
thread,  are  denominated  according  to  the 
number  of  these  hanks  which  will  weigh 
a  pound.  The  hank  of  840  yards  in  length 
is  the  measure  used  in  all  English  cotton- 
mills,  and  thus  affords  a  very  accurate  and 
convenient  standard  for  the  size  of  the 
cotton.  The  number  is  ascertained  by 
weighing  each  individual  hank  in  a  little 
weighing  instrument,  which  shews  by  an 
index  what  number  of  such  hanks  will 
weigh  a  pound  Each  bank  being  twisted 
up  is  suspended  on  the  hook  of  this  instru- 
ment, and  the  number  being  ascertained,, 
the  hank  is  put  on  a  proper  shelf  till  thej 
are  all  sorted.  Then,  by  a  table  on  pur- 
pose ,  it  is  seen  how  many  hanks  of  any 
number  will  weigh  10  lbs.  and  this  num- 
ber being  counted  out  from  any  one  shelf; 
is  packed  up  in  the  bundling  press,  and 
tied  in  papers,  marked,  and  sent  away  for 
market.  Sometimes,  the  cotton  intended 
for  weaving  is  warped  in  the  warping-miH 
before  it  is  sent  away  from  the  mill :  this 
saves  the  weaver  an  immense  deal  of  trou- 
ble. 

Some  of  the  twist  is  wound  on  quills 
for  the  shuttle ;  and  others,  again,  are 
formed  into  hanks,  some  of  which  are 
tightly  bound  round  at  certain  intervals 
previous  to  their  being  dyed,  in  order  to 
prevent  the  parts  so  ticd'from  taking  the 


MAN 


MAN 


colour.  This  is  done  that  the  threads  may 
be  disposed  to  warp  in  the  wearing  loom, 
so  as  to  produce  the  clouds  which  are 
seen  in  various  species  of  the  cotton  goods, 
especially  g-inghams. 

Some  of  the  cotton  thread  is  dyed  in  the 
hank,  and  other  cotton  which  is  intended 
•for  sewing,  knitting,  &c.  or  to  weave  fine 
g-oods,  is  bleached  ;  and  because  in  this 
process,  or  in  dyeing,  some  shrinking 
takes  place,  it  is  wound  from  the  hanks 
upon  bobbins  again  by  the  winding  ma- 
chine, and  from  these  bobbins  ^t  is  again 
reeled  into  hanks,  in  which  it  is  packed 
up  and  sent  to  market :  other  cotton 
thread  for  sewing,  mending,  and  domes- 
tic use,  is  wound  into  balls  of  a  figure  re- 
sembling a  cask,  and  the  many  intersec- 
tions of  the  thread  are  so  managed  as  to 
produce  a  very  beautiful  appearance. 

The  denominations  of  the  quality  of  the 
different  kinds  of  cotton  threads  are  chief- 
ly divided  into  yarn  and  twist,  and  this  is 
called  mule  twist,  or  water  twist,  as  it  is 
spun  either  in  the  mule  or  water-frame. 
That  thread  which  is  denominated  water- 
twist,  is  used  for  weaving  calicoes,  &c. 
It  is  spun  hard,  that  is,  with  a  great  deal 
of  twist,  so  that  it  forms  a  strong-  hard 
thread.  It  is  manufactured  of  all  numbers, 
from  10  to  60  hanks  per  pound. 

The  mule-tw  ist  is  used  for  weaving  mus- 
lins and  the  finest  cotton  goods.  The  es- 
sential difference  between  this  and  the  wa- 
ter-twist are,  that  the  mule  produces  much 
liner  articles  than  are  attempted  on  the 
water-frame,  at  the  same  time  it  makes  a 
softer  thread.  As  it  requires  much  less 
power  to  work  it  than  the  water-frame, 
the  manufacturer  spins  every  thing  in  the 
mule  which  will  admit  of  it;  but  it  will 
only  produce  the  soft  kinds  of  thread. 
The  mule  will  spin  all  numbers,  from  the 
lowest  to  loO  or  170  hanks  per  lb. 

Stocking  yam  is  spun  softer  than  twist, 
and  two  tii l  eads  are  afterwards  doubled 
together  in  the  doubling-  machine,  and 
then  slightly  twisted  round  each  other  in 
the  twisting  machine.  Sometimes  one  of 
the  threads  is  dyed  black,  or  blue,  before 
the  twisting,  and  then  it  produces  a 
speckled  thread,  which  is  called  one-thread 
white.  This  yarn  is  chiefly  used  in  the 
stocking-frame ;  it  is  spun  in  all  numbers, 
from  10  hanks  in  the  pound  up  to  60.  The 
threads  of  stocking-yarn  are  but  slightly 
twisted,  so  that  its  composition  of  two 
threads  is  always  distinctly  visible. 

Sewing  cotton  is  made  either  from  twist 
or  cotton  yarn  doubled,  and  twisted  very- 
hard  together  by  passing  it  a  second  time 
through  the  spinning  frame,  so  as  to  form 
a  strong  thread,  which  may  be  compared 


to  a  small  rope,  as  the  two  threads  make 
one  very  compact  and  defined  thread. 

Mending  cotton  is  the  same  as  sewing, 
but  of  less  tw  ist :  indeed  the  distinction 
is  trifling. 

Knitting  cotton  is  twisted  with  two  or 
three  threads,  but  not  so  hard  twisted  as 
sewing  cotton,  though  it  is  harder  than 
mending  This  cotton  is  frequently  bleach- 
ed after  it  is  twisted. 

Candlewick  cotton  is  a  very  loose  coarse 
thread,  made  from  the  cheapest  and  most 
inferior  kind  of  cotton  :  being  only  intend- 
ed for  the  wick  of  candles,  no  great  care 
is  used  in  the  manufacturing.  A  great 
deal  of  candlewick  is  made  from  tow 
which  is  bleached,  and  makes  an  article 
something  like  the  cotton  in  appearance, 
but  by  no  means  equal  to  it  in  quality. 
This  is  known  by  the  cant  term  of  bump, 
and  many  large  mills  are  employed  in 
spinning-  it.  The  cotton  candlewick  is 
known  by  the  name  of  Turkey,  which  is 
made  from  Smyrna  or  other  cheap  inferior 
kinds  of  cotton.  It  is  spun  generally  about 
lOh  to  11  hanks  per  lb.,  and  sent  off  to 
market  wound  up  in  large  balls. 

To  pursue  the  progress  of  the  cotton 
after  being  spun  into  twist,  we  must  re- 
move from  the  cotton-mill  to  the  cottage 
of  the  weaver.  Here,  the  warp  being  fix- 
ed in  the  loom,  or,  in  the  language  of  the 
weaver,  warped,  it  is  divided  to  give  pas- 
sage to  the  weft  in  the  shuttle,  either  by 
two,  three,  or  more  treadles :  or  if  the 
pattern  or  course  of  changes  in  the  order 
of  raising  and  depressing  the  threads  of 
the  warp  be  various,  so  that  the  weaver 
could  not  manage  the  requisite  number  of 
treadles,  it  is  done  by  a  great  number  of 
strings  which  pass  over  pullies  above  the 
loom,  and  are  drawn  one  after  another  by 
a  little  boy,  above  whose  head  they  are 
disposed  in  two  rows  by  the  sides  and 
between  two  looms.  These  looms  are, 
therefore,  called  draw -boys.  These  boys 
will  shortly  be  set  aside  for  machinery, 
which  is  rapidly  introducing  a  substitute. 
For  the  formation  of  sprigs,  he.  of  vari- 
ous colours,  there  are  often  as  many  shut- 
tles as  colours,  or  a  number  of  little  swi- 
vel looms,  such  as  they  use  for  the  weav- 
ing of  tapes,  introduced  occasionally,  as 
many  as  there  are  sprigs  in  the  breadth  ol 
apiece.  Quiltings  appear  to  be  two  dis- 
tinct cloths,  tied  as  it  were  together  by 
ditches,  which  go  through  both  cloths, 
and  in  some  cases,  as  in  bed-quilts,  there 
is  a  shuttle  which  throws  in  a  quantity  ol 
coarsely  spun  cotton,  to  serve  as  a  kind  ol 
wadding.  The  counterpanes  are  woven 
with  two  shuttles,  one  containing  a  much 
coarser  weft  than  the  other  ;  the  coarser 


MAN 


MAN 


of  the  threads  is  picked  up  at  intervals 
with  an  iron  pin,  rather  hooked  at  the 
point,  so  as  to  form  knobs  disposed  in  a 
sort  of  pattern. 

When  the  goods  have  come  from  the 
loom,  most  sorts  of  them,  previously  to 
being  bleached,  are  fired  or  dressed,  by 
being-  drawn,  and  that  not  very  quickly, 
over  red-hot  cylinders  of  iron,  by  which 
the  superfluous  nap  is  burnt  off.  To  see 
such  an  operation  performed  upon  so 
combustible  a  substance,  naturally  fills  a 
stranger  with  the  utmost  concern  and 
astonishment.  They  are  then  washed  in 
a  wheel  with  soap  and  water,  and  having 
been  well  scoured  with  an  alkaline  lixi- 
vium, are  dipped  in  the  oxygenated  mu- 
riatic acid,  diluted  to  its  proper  strength. 
These  preparations  are  repeated  alternate- 
ly, till  the  goods  have  attained  the  requi- 
site whiteness  5  and  between  each  dipping 
they  are  laid  out  upon  the  ground,  and 
exposed  to  the  action  of  the  sun  and  air. 
When  completely  bleached,  they  are  ei- 
ther smoothed  upon  long  tables  with 
smoothing  irons,  or  calendered  ;  that  is, 
stretched  and  pressed  between  a  course  of 
rollers,  by  which  they  acquire  a  fine  gloss. 
Calicoes  are  printed  exactly  in  the  same 
way  as  the  kerseymeres,  but  the  works 
iire  usually  upon  a  much  larger  scale.  See 
Printing. 

Thicksets,  corduroys,  velveteens,  &.c. 
are  cut  upon  long  tables,  with  a  knife  of 
a  construction  somewhat  like  the  sting  of 
a  wasp,  terminating  in  a  very  sharp  point, 
defended  on  each  side  by  a  sort  of  sheath. 
This  point  is  introduced  under  the  upper 
course  of  threads  which  are  intended  to 
be  cut,  and  with  great  ease  carried  for- 
ward the  whole  length  of  the  table. 

The  rapid  increase  of  the  cotton  t"ade 
in  England  appears  to  have  been  owing, 
in  a  great  measure,  to  the  more  liberal 
introduction  of  machinery  into  every  part 
of  it,  than  into  any  other  of  their  staple 
manufactures.  The  utility  and  policy  of 
employing  machines  to  shorten  labour,  has 
been  a  subject  which  has  exercised  the 
pens  of  many  ingenious  writers,  while  their 
introduction  into  almost  every  branch  of 
manufacture  has  been  attended  there  in 
the  outset  with  much  riot  and  disorder. 
They  are  undoubtedly  wonderful  produc- 
tions of  human  genius,  the  progressive 
exertions  of  which  neither  can  nor  ought 
to  be  stopped  ;  they  enable  a  manufac- 
turer to  produce  a  better  article  than  can 
be  made  by  the  hand,  in  consequence  of 
the  uniformity  and  certainty  of  their  ope- 
rations, and  at  a  much  lower  price,  in  con- 
sequence of  the  vast  quantities  of  goods 
they  are  capable  of  performing.  And  al- 
VOL.  II. 


though  they  do,  undoubtedly  on  their  first 
introduction,  throw  some  persons  out  of 
employ,  by  changing  the  nature  and  course 
of  business,  they  almost  immediately 
make  up  for  the  inconvenience  by  aston- 
ishingly multiplying  the  absolute  quantity 
of  employment.  If  they  have  taken  away 
work  from  carders  and  spinners,  they 
have  returned  it  them  back  tenfold,  as 
winders,  warpers,weavers,  dressers,  dyers, 
bleachers,  printers,  &.c. 

It  is  this  machinery  which  we  have  now 
to  explain.  An  extensive  cotton  mill  con- 
tains most  interesting  specimens  of  human 
ingenuity  and  resource,  and  shews  in  a 
striking  manner  what  may  be  done,  when 
the  talents  of  a  great  number  of  indivi- 
duals are  directed  to  one  common  object, 
and  where  the  most  trifling  part  is  of  such 
importance  (from  the  frequent  repetition 
of  it  which  is  necessary)  as  to  become 
worthy  the  consideration  of  the  manufao 
turer  to  devise  machinery  for  accomplish- 
ing it  in  a  better  or  cheaper  manner.  There 
is  in  the  cotton  trade  in  England  such  a 
spirit  of  improvement,  that  they  have,  as  a 
body,  less  prejudice  in  favour  of  old  esta- 
blished customs  than  perhaps  any  other 
class  of  men  ;  this  is  doubtless  a  reason  of 
the  great  perfection  of  their  art,  as  they 
have  made  trials  of  new  ideas,  without 
those  years  of  reflection  which  men  in 
other  trades  require  before  they  will  ven- 
ture to  embark  in  any  new  improvement, 
though  ever  so  promising  and  favourable 
in  appearance. 

Our  readers,  who  are  unacquainted 
with  the  subject,  will  now  by  this  sketch 
have  obtained  such  a  general  idea  of  the 
cotton  manufacture,  as  will  enable  them 
to  comprehend  the  technical  terms  which 
are  necessary  to  be  used  in  the  subsequent 
explanation  of  the  machinery,  and  those 
references  which  must  sometimes  be  made 
from  one  process  to  another.  A  large  cot- 
ton mill  is  generally  a  building  of  five  or 
six  stories  high  :  the  two  lowest  are  usu- 
ally for  the  spinning  frames,  if  they  are 
for  water  twist,  because  of  the  great 
weight  and  vibration  caused  by  these  ma- 
chines. The  third  and  fourth  floors  con- 
tain the  carding,  drawing,  and  roving 
machines.  The  fifth  story  is  appropriated: 
to  the  reeling,  doubling,  twisting,  and 
other  operations  performed  on  the  finish- 
ed thread.  The  sixth,  which  is  usually 
in  the  roof,  is  for  the  batting  machine,  or 
opening  machine,  and  for  the  cotton  pick- 
ers, who,  for  a  large  mill,  are  very  numer- 
ous. This  last  is  not  always  so  occupied, 
many  manufacturers  thinking  it  better  to 
have  out-buildings  for  these  parts  of  the 
process,  and  only  to  have  such  parts  ia 
E 


MAN 


MAN 


the  null  as  require  the  aid  of  the  large 
water-wheel, or  steam-engine,  Much  turns 
the  whole  mill.  If  the  mule  is  used  for 
spinning  instead  of  the  water-frame,  then 
the  cards  are  usually  put  beiow,  because 
they  are  then  the  heaviest  and  most  pow- 
erful machinery. 

The  following  notes  on  the  subject  of 
arranging  Cotton  Machinery,  have  been 
communicated  by  a  very  intelligent  gen- 
tleman of  Philadelphia,  who  collected 
them  with  a  view  of  obtaining  the  infor- 
mation necessary  to  embark  in  the  busi- 
ness. 

We  give  them  in  the  manner  they  were 
originally  written,  lest  in  attempting  to 
systematize  them,  we  might  render  them 
less  intelligible. 

1.  The  following  description  is  designed 
to  apply  to  run  1000  spindles. 

2.  Power  required — 90  spindles  in  wa- 
ter frames  are  considered  the  work  of  a 
one  horse  power,  this  includes  all  the 
work  of  previous  apparatus  for  carding, 
roving,  twisting,  doubling,  &c  &c.  Water 
frames  are  so  called,  because  they  were 
the  first  invention  for  spinning  by  water. 
Spindles  are  also  hung  in  throstles,  which 
is  a  mode  of  applying  the  power  to  more 
advantage ;  but  it  is  not  durable  in  regard 
to  the  machinery,  but  is  erected  at  less 
expence.  They  are  also  hung  in  mules, 
which  may  be  worked  by  hand  or  water, 
but  it  is  not  perpetual  spinning".  A  one 
horse  power  would  turn  120  spindles  in 
throstles,  and  260  spindles  in  mules.  The 
cotton  spun  in  water  frames  is  the  best 
for  the  chain,  and  in  the  mules  for  the  fill- 
ing the  proportionate  price  of  cotton 
yarn,  in  England,  was  commonly  as  fol- 
lows : — When  No.  15,  sold  at  4*.  6d.  per 
pound  sterl.  spun  on  mules — No.  15,  or 
15  skeins  to  a  pound,  water  twist,  would 
bring  5s.  6^.  The  water  twist  is  much 
harder,  and  the  mule  twist  much  softer. 

3.  A  paper-mill  engine  requires  a  ten 
horse  power.  Hence,  the  power  which 
would  turn  an  engine,  would  turn  900 
spindles  in  water  frames,  1200  in  throst- 
les, or  2600  in  mules,  with  all  the  neces- 
sary accompanying  apparatus. 

4.  Water  frames  and  throstles,  if 
equally  well  made,  will  spin  equally  well 
all  the  Numbers,  from  No.  6  to  No.  40,  or 
No.  44,  liner  than  the  last  is  done  by 
mulcs — which  stretch  the  yarn  after  it  has 
received  part  of  the  twist,  and  then  give 
it  more  twist.  Coarser  than  the  lower  num- 
ber, down  from  No.  6  to  No.  1. ;  which 
last  is  coarse  candle  wick,  is  made 
by  spindles  in  mules,  called  stretchers. 

"  5.  The  cost  of  erecting  the  whole  ap- 
paratus, to  include  the  carding,  drawing, 


roving,  spinning,  and  reeling,  is  generally 
averaged  on  the  spindles.  The  carding, 
&.c  is  the  same  cost,  let  whatever  spin- 
dles be  used — but,  if  water  frames 
are  used,  the  cost  will  be  about  eighteen 
dollars  per  spindle ;  if  throstles,  the 
cost  will  be  about  £>16.75 ;  and,  if  mules, 
perhaps  a  little  less. — the  above  includes 
every  thing,  except  for  the  manufactory 
and  moving-  power.  The  moving  consists 
of  the  water  wheel  and  great  cog  wheel, 
to  turn  an  upright  shaft ;  after  this  come 
the  drums,  which  are  three  feet  diameter 
for  throstles,  and  mules  and  cards,  and 
move  45  times  in  a  minute — and  for  water 
frames,  the  drums  run  horizontal,  are  4 
feet 4  inches  in  diameter:  they  are  thus 
calculated  to  afford  the  velocities  requir- 
ed by  each  description  of  machinery  to 
move  together — for  water  frames,  the 
drums  turn  36  times  per  minute — the 
difference  between  the  velocities  of  the 
drums  for  the  throstles  which  move  45 
times  in  a  minute,  and  that  of  the  drums 
for  the  water  frames  which  move  34  to 
36,  is  made  by  the  wheel  work  from  the 
several  horizontal  shafts  which  receive 
motion  from  the  upright. 

6.  In  regard  to  the  house  or  manufac- 
tory, it  is  always  necessary  that  it  should 
be  built  4  stories  high,  and  5  stories  are. 
better — the  work  to  be  distributed  as  fol  - 
lows : 

1.  The  upper  stories  are  occupied  by 
the  carding  and  roving  work. 

2.  The  next  to  the  upper  for  the  same. 
3  and  4.  For  spinning. 

5.  The  lower  story  for  reeling  and 
hacking — the  carding  and  spinning  will 
not  do  well  together  on  account  of  the 
dust. 

The  best  width  of  a  house  is  from  36  to 
38  feet  wide  in  the  clear — the  length  of  a 
building  for  1000  spindles,  if  4  stories 
high,  will  require  36  feet  long  ;  the  sto- 
ries if  for  throstles  or  mules,  must  be  10 
feet  high — the  carding  rooms  in  any  case, 
must  be  10  feet;  but  the  machinery  for 
water  frames  will  be  suited  very  well  at  8 
feet  high. 

7.  The  only  heat  required  is  for  warm  - 
ing  the  mill,  and  there  is  no  other  risk  of 
fire  than  what  arises  from  this  cause,  or 
from  the  lighting  it  for  work  at  nigh'; 
— however,  all  must  be  excepted  which 
arises  from  friction,  or  the  slipping  ot 
bands — which  is  very  little  or  none,  if  care 
is  taken. 

8.  Cotton  will  not  spin  unless  the  hea< 
is  supported  to  48  degrees,  and  upwards 
— and  all  damp  must  be  guarded  against. 

9.  In  mills  of  common  lengths,  the 
power  is  always  applied  from  the  end  toar 


MAN 


MAN 


upright — the  upright  goes  through  the 
several  stories  coupled  together  at  each  ; 
but  if  the  length  is  very  great,  the  water 
wheel  is-generally  at  the  side. 

10.  It  would  require  12  months  to  erect 
1000  spindles. 

11.  It  would  require  5  children  to  every 
100  spindles  ;  or  50  children,  or  40  chil- 
dren and  2  or  3  women  to  1000.  Four 
men  woidd  be  necessary  in  addition — 1  for 
an  overseer,  1  for  the  spinning  master,  1 
for  a  carding  master,  and  1  for  the  packing 
and  sending  awa)'. 

12.  A  machine  house  ought  to  be  built 
2  stories  high,  30  feet  long  by  28  feet 
wide,  to  erect  and  build  the  machines  in. 

13.  The  desc.  iption  of  children  to  be 
employed,  is  from  the  age  of  6  to  14 
years,  male  and  female,  indiscriminately; 
some  stout  children  as  young  as  4  years, 
have  been  employed  :  but  the  best  age  is 
the  medium  9  to  12.  The  employment 
of  the  youngest  children  is  to  wind  the 
rovings  on  spools — the  next  class  are  em- 
ployed in  attending  the  roving  frames  and 
the  carding  machines,  and  in  taking  the 
rolls  from  the  cards,  and  setting  them  un- 
der the  drawing  frames — the  next  class 
are  employed  in  attending  the  water 
frames  or  the  throstles,  the  object  is  to 
piece  the  ends  when  the  cotton  breaks  on 
the  spindles — the  elder  class  is  employed 
in  reeling  the  cotton  from  the  bobbins,  and 
in  doubling  and  twisting  it  if  required  ; 
frequently  young  women  are  employed 
for  this  business.  A  day's  work  is  com- 
monly called  11  hours  :  this  allows  time 
only  for  their  meals — the  work  is  every 
day  in  the  week.  It  is  sometimes  the 
practice  to  work  only  10  hours,  and  give 
schooling  for  2  or  3  hours  At  the  manu- 
factories in  New-York,  (Stone  &  Dyson) 
they  take  the  children  from  the  Poor- 
house,  and  find  them  compleatly ;  em- 
ploy them  10  J  hours,  and  school 
them  2J  hours.  In  winter,  work  is  be- 
gun early  enough  in  the  morning  to  ac- 
complish the  day's  work ;  and  there  is 
considerable  advantage  obtained  to  the 
work  by  the  lighting  of  the  candles.  It 
is  observed  that,  when  the  candles  or 
lamps  are  lighted  at  night,  the  facility 
with  which  the  work  moves  is  so  much 
more  as  to  require  water  to  be  taken 
■from  ofT the  wheels — there  is  greater  ad- 
vantages beyond.this,  in  beginning  early 
in  the  morning,  in  saving  the  risk  from 
fire. 

14.  The  speed  of  the  work  is  regulated 
by  a  clock,  having  one  generally  in  the 
counting-house,  and  a  shaft  running 
through  to  a  plate  near  it,  having  a  reduc- 
ed motion  to  keep  the  speed  properly. 


U.  One  hundred  spindles  may  be  set 
to  work  at  the  proportionate  expence  of 
1000,  say  for  gl  800— but  not  less  than 
100  spindles,  for  100  spindles  is  required. 
One  set  of  cards,  viz,  one  breaker 
and  one  card.  < 
One  set  of  frames,  viz.  one  stretching 
frame,  and  one  roving  frame 
One  throstle  would  hold  100  spindles,  and 
in  this  case  it  would  cost  only  gl675. — 
There  is,  however,  enough  of  the  carding 
and  roving  apparatus  to  suffice  for  2  wa- 
ter frames  which  would  run  72  spindles, 
each  144. 

16.  On  the  same  water  frame  or  thros- 
tle, yarn  may  be  spun  from  No.  10  to  20, 
or  from  20  to  30,  or  30  to  40  ;  but  not  No. 
10  to  40,  on  one  frame,  nor  a  greater  va- 
riation than  10  numbers.  The  yarn  usu- 
ally wanted  in  this  countrv,  is  from  No. 
12  to  20.  The  yarn  from  f  0  to  20,  is  the 
most  profitable,  and  is  of  very  little  differ- 
ence in  profit. 

17.  Yarn  is  spun  by  machinery  in  Eng- 
land, to  No.  160— to  No.  260,  for  extreme 
fine  cambric  muslin.  To  have  the  most 
careful  persons  and  spin  the  very  finest 
yarn,  is  the  most  profitable. 

18.  I  cannot  tell  what  quantity  of  yarn 
is  spun  per  day  by  the  spindles,  but  the 
coarsest  spins  the  greatest  weight.  The 
prices  of  the  yarn  cannot  be  recollected  ; 
but  No.  10  is  101  cents  per  pound,  the 
wholesale  price ;  110  cents  the  retail 
price  ;  if  the  yarn  is  sold  unbleached,  8 
cents  per  pound  less  is  paid  for  it.  No. 
36,  I  think,  is  Jg2.60  per  pound  whole- 
sale ;  retail,  8  cents  per  pound  more. 

19  The  most  advantage  is  derived 
from  the  true  management,  of  thecal  ding 
and  roving — the  cotton  is  to  pass  through 
the  breaker  and  through  the  card,  then 
through  the  roving  frames  according  to 
the  number  of  the  yarn  which  is  to  be 
spun.  This  is  in  order  to  draw  the  harl 
nicely  and  evenly  together,  in  the  same 
manner  as  flax  is,  by  repeatedly  drawing 
over  the  hackle — if  less  than  No.  6,  it 
commonly  passes  through  but  once ;  if 
more,  it  goes  through  twice  or  more. 
Two  rovings  are  commonly  put  together, 
which  will  draw  better  than  more.  As 
many  as  four  are  put  through  sometimes, 
but  it  is  not  so  well  as  two  or  three  ;  and 
the  two  or  three  are  drawn  down  to  the 
same  thickness  as  one.  Numbers  from  1 
to  5,  pass  through  the  roving  frames  once 
from  5  to  12  ;  twice,  12  to  20,  3  to  4  times  ; 
above  20  to  30,  four  or  five  times,  st-idom 
o.  never  more  than  six.  In  the  high  num- 
bers the  wheels  are  altered,  so  that  the 
roving  is  drawn  out  finer  by  putting  the 
driving  wheel  on  the  front  roller  smaller, 


MAN 


MAN 


and  the  driver  of  the  back  roller  lar- 
ge*. 

20.  The  harl  of  the  cotton  is  not  injured 
hi  the  roving  frames  by  being  drawn  out, 
as  the  rollers  are  so  far  apart  that  the 

*  fibres  become  separated  between  the  rol- 
lers and  drawn  apart 

21.  The  harl  of  the  cotton  is  mostly  in- 
jured in  the  carding,  and  which  ought  to 
be  most  nicely  attended  to  :  it  arises  from 
various  causes — the  front  rollers  may  be 
too  far  apart,  and  allow  the  card  to  feed 
too  fast,  and  the  cotton  to  go  in,  in  flocks  j 
the  fast  cards  may  be  screwed  too  close. 

22.  The  cards  and  breakers  are  both  to 
be  occasionally  sharpened  about  every  2 
days  for  the  card,  and  about  every  week 
for  the  breakers ;  this  is  done,  giving 
them  a  reverse  motion,  and  holding  be- 
fore them  a  board  faced  with  glue  and 
emery  :  this  is  to  be  done  very  carefully, 
15  or  20  minutes  is  generally  enough  ; 
the  board  is  to  be  held  lightly,  otherwise 
by  bearing  hard,  it  is  apt  to  leave  a  quan- 
tity of  the  iron  hanging  to  the  end  of  the 
teeth  and  beards  them,  which  is  called 
fish  hooking  them,  and  this  never  comes 
off,  and  ruins  the  card — the  fast  cards  are 
done  by  hand.  In  large  factories  they  use 
a  cylinder  covered  w  ith  emery,  and  run  it 
round,  and  thus  sharpen  the  fast  cards. 
The  speed  in  sharpening  is  about  the 
same,  as  if  the  card  was  at  work,  say 
about  75  times  a  minute.  Some  of  the 
best  cotton  spinners  do  not  run  the  cards 
more  than  65  times  a  minute,  and  this  it 
is  considered,  is  better  than  fast  work — 
above  90  is  considered  too  fast,  and 
breaks  the  harl. 

23  The  teeth  of  the  cylinder  are  about 
one-sixteenth  of  an  inch  from  those  of  the 
fast  card;  the  cylinder  ought  to  be  nicely 
balanced,  otherwise  the  heavy  side  is  apt 
to  fly  off  to  a  greater  diameter  than  the 
light  one,  and  make  bad  work — the  card 
leathers  to  be  well  attended  to,  that  they 
are  well  nailed  on,  and  do  not  extend  in 
places. 

24.  When  it  is  required  to  spin  fine 
yam,  f*n  r  than  No.  20,  stretchers  are 
used  to  take  the  yarn  from  the  roving- 
frames,  and  stretch  it  before  it  is  spun. 
The  same  stretchers  on  which  yarn  is 
spun  from  No.  1  to  10,  are  used  for 
stretching  from  the  rovings.  Yarn  from 
No.  10  to  20,  need  not  pass  through  the 
stretchers.  Yarn  if  ever  so  fine,  is  never 
stretched  more  than  once 

25.  The  difference  in  construction  be- 
tween the  water  frames  and  throstles,  is 
this  :  In  water  frames,  the  motion  is  com- 
municated from  a  horizontal  drum  turn- 
ed from  a  small  iron  shaft,  from  the  main 


shaft,  which  drum  gives  motion  to  the 
pulleys  and  binders :  each  pulley  and 
each  binder  turns  4  spindles  and  threads 
— thus  any  4  may  be  stopped  at  once — 
this  is  the  best  mode  of  spinning  and  most 
saving — It  is  the  most  proper  when  the 
persons  are  not  fully  acquainted  with  it. 
The  throstles  are  turned  by  a  long  verti- 
cal tin  drum,  which  turns  about  60  on 
each  side  of  it ;  there  is  no  mode  of  stop- 
ping less  than  the  whole  at  once. 

26.  100  spindles  in  a  mule  will  spin  in 
a  day  about  30  pounds  from  No.  8  to  No. 
10.  No.  8  sells  for  62i  cents.  No.  10 
for  68  cents.  From  No.  10  to  No.  20, 
the  quantity  may  decline — so  that  No.  20, 
will  be  about  10  pounds,  and  sells  for 
about  $1.20. 

27.  A  mule  spindle  will  spin  a  hank  and 
an  half  per  day,  to  two  hands,  according 
to  the  goodness  of  the  spinner — and  in 
weight,  a  pound  consists  of  as  manv 
hanks  as  the  numbers  are,  as  10  hanks  of 
No.  10  are  a  pound,  20  of  No.  20,  &c. 

28.  A  throstle  spindle  about  2^  hanks 
per  day. 

29.  Water  frames  about  as  much  as 
the  throstle. 

30.  The  mode  the  numbers  are  deter- 
mined, is  by  weighing  the  cotton  and 
spreading  it  on  a  certain  distance  as  it 
goes  on  the  cloth  into  the  breaker ;  and  it 
is  weighed  again  on  its  coming  oft'  the  cy- 
linder of  the  breaker. 

31.  I  made  a  calculation  at  Baltimore, 
regarding  the  expence  of  working  a  cot- 
ton mill,  compleat,  from  beginning  to 
end,  and  calculate,  that  business  well 
managed,  will  afford  to  turn  out  cotton  at 
1^  cents  per  hank,  to  include  every  ex- 
pence  of  work  people,  children,  &,c.  and 
keep  the  machinery  all  in  compleat  order, 
except  finding  oil  and  candles,  for  light- 
ing and  coal  or  fuel.  This  calculation  is 
made  for  1000  spindles — the  quantity  of 
mules  and  throstle  frames  about  equal. 

32.  If  the  hands  become  well  acquaint- 
ed with  the  business,  the  following  hands 
will  be  sufficient  to  conduct  it : — Three 
men.  1  superintendant,  1  for  the  carding 
and  roving,  and  1  for  spinning;  5  girls  or 
boys  for  the  spinning' ;  12  girls  or  boys  for 
carding,  roving,  and  drawing,  and  wind- 
ing, rovings  and  reeling. 

33.  Thomas  Wharton,  who  now  resides 
at  Baltimore,  and  conducts  the  machinery 
for  W.  Levering,  lias  constructed  a  very 
excellent  machin<:  for  spinning  Max  or  tow, 
and  it  is  from  Berbank's  invention  of  Toad- 
hole,  near  Matlock,  Derbyshire. — M'Don- 
ald  has  constructed  a  loom  to  go  by  wa- 
ter. 


MAN 


MAN 


ESTIMATE. 


Otic  Warding  engine,  24  inches,  with  workers  and  stressers  $500 

One  throstle  of  144  spindles,  at  $6  per  spindle   864 

Two  drawing  frames,  each  four  heads,  with  four  boss'd  rollers      ....  240 

One  roving,  or  fly  frame,  24  spindles  .......   360 

[If  cann  frames  are  preferred,  they  will  come  at  $25  per  pair,  say  10  pair.] 

One  water  frame  of  120  spindles,  at  fof  per  spindle   840 

If  you  have  the  throstle  and  water  from  the  number  of  spindles  above-mention- 
ed, you  will  require  another  card,  same  size  as  above   500 


it  is  to  he  observed,  that  the  work  will  be  well  executed,  and  of  good  materials, 

for  the  above  prices. 
The  number  of  spindles  to  be  supplied  by  each  card  will  entirely  depend  on  the 
number  of  yarn  you  are  spinning—the  calculation  which  1  have  given  you  is 
for  No.  10,  or  thereabout 
Mule  of  144  spindles,  at  $3  per  spindle    432 


Manufacture  of  Coke.    See  Coal. 

Manufacture  of  Cutlery.    See  Cutlery. 

Manufacture  of  German  Asses-skin. — 
Particulars  of  the  Patent  granted  to  Mr. 
George  Cummings,  of  Ludgate  street, 
London,  Toyman  ;  for  his  Invention  of  a 
Composition  to  put  on  all  sorts  of  Skins, 
Paper,  or  Linen,  for  drawing  or  writing 
on  with  pen  and  ink,  or  pencil,  and  rub- 
bing clean  off  again. 

The  invention  consists  of  a  composition 
to  put  on  all  sorts  of  skins,  paper,  or  linen, 
for  the  use  of  drawing  or  writing  on  with 
pen  and  ink,  or  pencil,  and  rubbing  clean 
oft'  again,  and  to  form  it  into  a  memoran- 
dum book,  distinguished  by  putting  the 
name  of  each  day  of  the  week  on  the  top 
of  each  leaf  of  the  book,  and  for  other 
uses  and  purposes,  is  to  be  performed  in 
manner  following  ;  that  is  to  say,  take  ei- 
ther vellum,  parchment,  very  fine  cloth, 
or  paper,  and  stretch  it  in  a  frame  as 
tight  as  possible.  Then  take  twelve  pounds 
of  white  lead,  and  pound  it  very  fine ;  add 
thereto  one  third  part  of  the  best  plaister 
of  Paris,  and  one  fourth  part  of  the  best 
stone  lime  ;  pound  them  well,  mix  them 
well  together,  and  grind  them  very  fine 
with  water.  Then  take  a  new  glazed 
vessel,  and  dissolve  six  or  seven  pounds 
of  the  best  double  size,  over  a  fire,  and 
mix  the  above  ingredients  in  this,  till  it  is 
of  such  a  consistenee  as  to  lay  on  with  a 
brush.  Then  lay  three  or  four  layers  on 
the  skin  or  cloth,  as  smooth  as  possible  ; 
observing  that  the  skin  is  dry  each  time, 
before  a  second  layer  is  put  on.  Then  take 
the  best  nut  or  linseed  oil,  and  to  every 
pound  of  this  oil  add  four  ounces  of  the 
best  white  varnish,  and  mix  them  well  to- 
gether. Then  put  on  three  or  lour  layers 
of  this  oil,  thus  prepared,  each  time"  ex- 


posing it  to  the  air  till  it  is  thoroughly 
dry :  this  is  for  the  white  sort.  For  a  brown 
or  yellow,  add  to  every  pound  of  the  above 
three  or  four  ounces  of  the  best  stone  oker, 
or  orpiment,  or  Dutch  pink,  and  three  or 
four  ounces  of  litharge.  These  must  be 
well  ground  with  very  old  linseed  oil,  and 
laid  on,  as  smooth  as  possible,  ten  or  twelve 
times  ;  exposing  it  each  time  to  the  air,  to 
be  thoroughly  dry,  before  a  second  layer 
is  put  on  :  observe  you  do  not  put  it  where 
any  dust  or  dirt  can  fall  upon  it.  It  may 
be,  by  the  same  process,  altered  to  any 
colour :  as  for  instance,  to  a  red,  by  tinc- 
turing it  with  vermilion,  or  the  like  ;  to  a 
blue,  Prussian  nine  ;  and  for  a  black,  by 
pounding  slate,  grinding  it  very  fine,  and 
mixing  with  it  as  much  ivory  black  as  will 
turn  it  to  a  fine  black  colour.  When  it  is 
thoroughly  dry,  you  may  write  on  it  with 
a  slate  pencil,  or  black  or  red  lead. 

Manufacture  of  Glass.    See  Glass. 

Manufacture  of  Glue.    See  Gelatin. 

Manufacture  of  Grained  Parchment- 
Description  of  the  method  employed  at 
Astracan  for  making  grained  Parchment 
or  Shagreen.  By  Professor  Pallas. 

The  process  for  preparing  shagreen  is 
a  very  old  oriental  invention,  not  practised 
in  Europe,  and  which,  as  far  as  we  know, 
has  never  yet  been  described ;  though 
Basil  Valentin  is  pretty  right  in  what  he 
says  of  it  in  general.  It  is  one  of  those 
arts  of  the  east,  which,  like  that  of  the 
Turkey  dye  for  cotton,  the  preparation  of 
Russia  leather,  isinglass,  &c.  have  re- 
mained unknown  and  unemployed,  not  be- 
cause they  are  kept  secrets,  but  because 
none  of  the  European  traveller  ever  took 
the  trouble  to  learn  them,  and  because 
the  materials  used  are  not  so  common  and 
so  cheap  in  Europe.    It  may  be  of  some 


MAN 


MAN 


utility,  therefore,  if  we  here  give  a  circum- 
stantial description  of  this  art  as  it  is 
practised  at  Astracan  by  the  Tartars  and 
Armenians,  especially  as  the  method  of 
these  people  is  perfectly  similar  to  that 
used  in  Turkey,  Persia,  and  various  parts 
of  Bucharia,  and  as  the  shagreen -makers 
of  Astracan  acknowledge  that  they  ob- 
tained the  process  originally  from  Per- 
sia. 

All  kinds  of  horses'  or  asses'  skin, 
which  have  been  dressed  in  such  a  man- 
ner as  to  appear  grained,  are  by  the  Tar- 
tars called  smnver,  by  the  Persians  sogre, 
and  by  the  Turks  sagri,  from  which  the 
Europeans  have  made  shagreen  or  chagrin. 
The  Tartars  who  reside  at  Astracan,  with 
a  few  of  the  Armenians  of  that  city,  are 
the  only  people  in  the  Russian  empire  ac- 
quainted with  the  art  of  making-  shagreen. 
Those  who  follow  this  occupation  not 
only  gain  considerable  profit  by  the  sale 
of  their  production  to  the  Tartars  of  Cu- 
ban, Astracan,  andCasan,  who  ornament 
with  it  their  Turkey  leather  boots,  slip- 
pers, and  other  articles  made  of  leather; 
but  they  derive  considerable  advantage 
from  the  great  sale  of  horses'  hides, 
which  have  undergone  no  other  process 
than  that  of  being  scraped  clean,  and  of 
which  several  thousands  are  annually  ex- 
ported, at  the  rate  of  from  seventy -five  to 
eighty -five  roubles  per  hundred,  "to  Per- 
sia, where  there  is  a  scarcity  of  such 
hides,  and  from  which  the  greater  part 
of  the  shagreen  manufactured  in  that 
country  is  prepared.  The  hind  part  only 
of  the  hide,  however,  which  is  cut  out  in 
the  form  of  a  crescent  about  a  Russian  ell 
and  a  half  in  length  across  the  loins,  and 
a  short  ell  in  breadth  along  the  back,  can 
properly  be  employed  for  shagreen.  The 
remaining  part,  as  is  proved  by  experience, 
is  improper  for  that  purpose,  and  is  there- 
fore rejected. 

The 'preparation  of  the  skins,  after  being 
cut  into  the  above  form,  is  as  follows  : — 
They  are  deposited  in  a  tub  filled  with 
pure  water,  and  suffered  to  remain  there 
for  several  days,  till  they  are  thoroughly 
soaked,  and  the  hair  has  dropped  off*. 
They  are  then  taken  from  the  tub,  one  by 
one,  extended  on  boards  placed  in  an  ob- 
lique direction  against  a  wall,  the  corners 
of  them,  which  reach  beyond  the  edges 
of  the  board,  being  made  fast,  and  the 
hair  with  the  epidermis  is  then  scraped  off 
with  a  blunt  iron  scraper  called  urak.  The 
skins  thus  cleaned  are  again  put  in  pure 
water  to  soak.  When  all  the  skins  have 
undergone  this  part  of  the  process,  they 
are  taken  from  the  water  a  second  time, 
spread  out  one  after  the  other  as  before, 


and  the  flesh  side  is  scraped  with  the  same 
kind  of  instrument.  They  are  carefully 
cleaned  also  on  the  hair  side,  so  that  no^ 
thing  remains  but  the  pure  fibrous  tissue, 
which  serves  for  making  parchment,  con- 
sisting of  coats  of  white  medullary  fibres^ 
and  which  has  a  resemblance  to  a  swine's 
bladder  softened  in  water. 

After  this  preparation,  the  workmen 
take  a  certain  kind  of  frames  called  pcilzt, 
made  of  a  straight  and  a  semi-circular 
piece  of  wood,  having  nearly  the  same 
form  as  the  skins.  On  these  the  skins  are 
extended  in  as  smooth  and  even  a  manner 
as  possible  by  means  of  cords  ;  and  dur- 
ing the  operation  of  extending  them  they 
are  several  times  besprinkled  with  water, 
that  no  part  of  them  may  be  dry,  and  oc- 
casion an  unequal  tension.  After  they 
have  been  all  extended  on  the  frames, 
they  are  again  moistened,  and  carried  in- 
to the  house,  where  the  frames  are  depo- 
sited close  to  each  other  on  the  floor  with 
the  flesh  side  of  the  skin  next  the  ground. 
The  upper  side  is  then  thickly  bestrewed 
with  the  black  exceedingly  smooth  and 
hard  seeds  of  a  kind  of  goose-foot,  (cheno- 
podium  album,)  which  the  Tartars  call 
alabuta,  and  which  grows  in  abundance, 
to  about  the  height  of  a  man,  near  the  gar- 
dens and  farms  on  the  south  side  of  the 
Volga  ;  and  that  they  may  make  a  strong 
impression  on  the  skins,  a  piece  of  felt  i* 
spread  over  them,  and  the  seeds  are  trod 
down  with  the  feet,  by  which  means  they 
are  deeply  imprinted  into  the  soft  skins. 
The  frames,  without  shaking  the  seeds, 
are  then  carried  out  into  the  open  air, 
and  placed  in  a  reclining  position  against 
a  wall  to  dry"!  the  side  covered  with  the 
seeds  being  next  the  wail,  in  order  that  it 
may  be  sheltered  from  the  sun.  In  this 
state  the  skins  must  be  left  several  clays 
to  dry  in  the  sun,  until  no  appearance  of 
moisture  is  observed  in  them  ;  when  they 
are  fit  to  be  taken  from  the  frames.  When 
the  impressed  seeds  are  beat  off  from  the 
hair  side,  it  appears  full  of  indentations 
or  inequalities,  and  has  acquired  that  im- 
pression which  is  to  produce  the  grain  of 
the  shagreen,  after  the  skins  have  been 
subjected  to  the  last  smoothing-  or  scrap  - 
ing-, and  have  been  dipped  in  a  ley,  which 
will  be  mentioned  hereafter,  before  they 
receive  the  dye. 

The  operation  of  smoothing  is  perform- 
ed on  an  inclined  bench  or  board,  which 
is  furnished  with  an  iron  hook,  and  is  co- 
vered with  thick  felt  or  sheep's  wool  on 
which  the  dry  skin  may  gently  rest.  The 
skin  is  suspended  in  the  middle  of  the 
bench  or  board  to  its  iron  hook,  by  means 
of  one  of  the  holes  naade  in  the  edge  of 


MAN 


MAN 


the  skin  for  extending  it  in  its  frame  as 
before  mentioned  ;  and  a  cord,  having-  at 
its  extremity  a  stone  or  a  weight,  is  at- 
tached to  each  end  of  the  skin,  to  keep  it 
in  its  position  while  under  the  hands  of 
the  workmen,  it  is  then  subjected  to  the 
operation  of  smoothing  and  scraping-  by 
means  of  two  different  instruments.  The 
first  used  for  this  purpose  culled  by  the 
Tartars  tokar,  is  a  piece  of  sharp  iron  bent 
like  a  hook,  with  which  the  surface  of  the 
shagreen  is  pretty  closely  scraped  to  re- 
move all  the  projecting-  inequalities.  This 
operation,  on  account  of  the  corneous 
hardness  of  the  dry  skin,  is"  attended 
with  some  difficulty ;  and  great  caution  is 
at  the  same  time  required  that  too  much 
of  the  impression  of  the  alabuta  seed  be 
not  destroyed,  which  might  be  the  case  if 
the  iron  were  kept  too  sharp.  As  the  iron, 
however,  is  pretty  blunt,  which  occasions 
inequalities  on  the  shagreen,  this  inconve- 
nience must  afterwards  be  remedied  by 
means  of  a  sharp  scraping- -iron  or  urakt 
by  which  the  surface  acquires  a  perfect 
uniformity,  and  only  faint  impressions  of 
the  alabuta  seed  then  remain,  and  such  as 
the  workman  wishes.  After  all  these  ope- 
rations, the  shagreen  is  again  put  into  wa- 
ter, partly  to  make  it  pliable,  and  partly 
to  raise  the  grain.  As  the  seeds  occasion 
indentations  in  the  surface  of  the  skin,  the 
intermediate  spaces,  by  the  operations  of 
smoothing-  and  scraping-,  lose  some  part  of 
their  projecting-  substance  ;  but  the  points 
which  have  been  depressed,  and  which 
have  lost  none  of  their  substance,  now 
swell  up  above  the  scraped  parts,  and 
thus  form  the  grain  of  the  shagreen.  To 
produce  this  effect,  the  skins  are  left  to 
soak  in  water  for  twenty-four  hours ;  after 
which  they  are  immersed  several  times  in 
a  strong-  warm  ley,  obtained,  by  boiling-, 
from  a  strong-  alkaline  earth  named  schqrd, 
which  is  found  in  great  abundance  in  the 
neighbourhood  of  Astracan.  When  the 
skins  have  been  taken  from  this  ley,  they 
are  piled  up,  while  warm,  on  each  other, 
and  suffered  to  remain  in  that  state  seve- 
ral hours  ;  by  which  means  they  swell, 
and  become  soft-  They  are  then  left 
twenty-four  hours  in  a  moderately  strong 
pickle  of  common  salt,  which  renders 
them  exceedingly  white  and  beautiful,  and 
fit  for  receiving  any  colour.  The  colour 
most  usual  for  these  skins  is  a  sea-green ; 
but  old  experienced  workmen  can  dye 
them  blue,  red,  or  black,  and  even  make 
white  shagreen. 

For  the  green  colour  nothing  is  neces- 
sary but  filings  of  copper  and  sal-ammo- 
niac. Sal-ammoniac  is  dissolved  in  water 
till  the  water  is  completely  saturated ;  and 


the  shagreen  skins,  still  moist,  after  being 
taken  from  the  pickle,  are  washed  over 
with  the  solution  on  the  ungrained  flesh 
side,  and  when  well  moistened  a  thick 
layer  of  copper  filings  is  strewed  over 
them  :  the  skins  are  then  folded  double, 
so  that  the  side  covered  with  the  filings  is 
innermost.  Each  skin  is  then  rolled  up 
in  a  piece  of  felt ;  the  lolls  are  all  ranged 
together  in  proper  order,  and  they  are 
pressed  down  in  an  uniform  manner  by 
some  heavy  bodies  placed  over  them,  un- 
der which  they  remain  twenty-four  hours. 
During  that  period  the  solution  of  sal-am- 
moniac dissolves  a  quantity  of  the  cupre- 
ous particles  sufficient  to  penetrate  the 
skin  and  to  give  it  a  sea-green  colour.  If 
the  first  application  be  not  sufficient,  the 
process  is  repeated  in  the  same  manner  ; 
after  which  the  skins  are  spread  out  and 
dried. 

For  the  blue  dye,  indigo  is  used.  About 
two  pounds  of  it,  reduced  to  a  fine  pow- 
der, are  put  into  a  kettle ;  cold  water  is 
poured  over  it,  and  the  mixture  is  stirred 
round  till  the  colour  begins  to  be  dissolv- 
ed. Five  pounds  of  pounded  alakar, 
which  is  a  kind  of  barilla  or  crude  soda, 
prepared  by  the  Armenians  and  Calmucs, 
is  then  dissolved  in  it,  with  two  pounds  of 
lime  and  a  pound  of  pure  honey,  and  the 
whole  js  kept  several  days  in  the  sun,  and 
during  tliat  time  frequently  stirred  round. 
The  skins  intended  to  be  dyed  blue  must 
be  moistened  only  in  the  natrous  ley 
schora,  but  not  in  the  salt  brine.  When 
still  moist,  they  are  folded  up  and  sewed 
together  at  the  edge,  the  flesh  side  being- 
innermost,  and  the  shagreened  hair  side 
outwards  ;  after  which  they  are  dipped 
three  times  in  the  remains  of  an  exhaust- 
ed kettle  of  the  same  dye,  the  superfluous 
dye  being  each  time  expressed  ;  and  after 
this  process  they  are  dipped  in  the  fresh 
dye  prepared  as  above,  which  must  not 
be  expressed.  The  skins  are  then  hung 
up  in  the  shade  to  dry  ;  after  which  they 
are  cleaned  and  paired  at  the  edges. 

For  black  shagreen,  gall-nuts  and  vi- 
triol are  employed  in  the  following  man- 
ner : — The  skins,  moist  from  the  pickle, 
are  thickly  bestrewed  with  finely  pulveris- 
ed gall-nuts.  They  are  then  folded  toge- 
ther, and  laid  over  each  other  for  twenty- 
four  hours.  A  new  ley, x of  bitter  saline 
earth  or  schora,  is  in  the  mean  time  pre- 
pared, and  poured  hot  into  small  troughs. 
In  this  ley  each  skin  is  several  times  dip- 
ped ;  after  which  they  are  again  bestrew- 
ed with  pounded  gall-nuts,  and  placed  in 
heaps  for  a  certain  period,  that  the  galls 
may  thoroughly  penetrate  them,  and  they 
are  dried  and  beat,  to  free  them  from  the 


MAN 


MAN 


dust  of  the  galls.  When  this  is  done, 
they  are  rubbed  over,  on  the  shagreen  side, 
with  melted  sheep's  tallow,  and  exposed 
a  little  in  the  sun,  that  they  may  imbibe 
the  grease  The  shagreen -makers  are 
accustomed  also  to  roll  up  each  skin  se- 
parately, and  to  press  or  squeeze  it  with 
their  hands  against  some  hard  substance, 
in  order  to  promote  the  absorption  of  the 
tallow.  The  superfluous  particles  are  re- 
moved by  means  of  a  blunt  wooden  scra- 
per (urak)  ;  and  when  this  process  is  fin- 
ished, and  the  skins  have  lain  some  time, 
a  sufficient  quantity  of  vitriol  of  iron  is 
dissolved  in  water,  with  which  the  sha- 
green is  moistened  on  both  sides,  and  by 
this  operation  it  acquires  a  beautiful  black 
dye.  It  is  then  dressed  at  the  edges,  and 
in  other  places  where  there  are  any  ble- 
mishes. 

To  obtain  white  shagreen,  the  skins 
must  first  be  moistened,  on  the  shagreen 
side,  with  a  strong  solution  of  alum.  When 
the  skin  has  imbibed  this  liquor,  it  is 
daubed  over  on  both  sides  with  a  paste 
made  of  flour,  which  is  suffered  to  dry. 
The  paste  is  then  washed  off  with  aluin 
water,  and  the  skin  is  placed  in  the  Sdn 
till  it  is  completely  dry.  As  soon  as  i  .s 
dry,  it  is  gently  besmeared  with  pure  malt- 
ed sheep's  tallow,  which  it  is  suffered  I ) 
Imbibe  in  the  sun  ;  and,  to  promote  the 
effect,  it  is  pressed  and  worked  with  the 
hands.  The  skins  are  then  fastened  in 
succession  to  the  before-mentioned  bench, 
where  warm  water  is  poured  over  them, 
and  the  superfluous  fat  is  scraped  off  with 
a  blunt  wooden  instrument.  In  the  last 
operation  the  warm  water  is  of  great  ser- 
vice. In  this  manner  shagreen  perfectly 
white  is  obtained,  and  nothing  remains  but 
to  pair  the  edges  and  dress  it. 

But  this  white  shagreen  is  not  intended 
so  much  for  remaining  in  that  state  as  for 
receiving  a  dark  red  dye,  because,  by  the 
above  previous  process,  the  colour  be- 
comes much  more  perfect.  The  skins 
destined  for  a  red  colour  must  not  be  im 
mersed-  first  in  ley  of  bitter  salt  earth, 
{sckora,)  and  then  in  pickle,  but,  after 
they  have  been  whitened,  must  be  left  to 
soak  in  the  pickle  for  twenty-four  hours 
The  dye  is  prepared  from  cochineal,  which 
the  Tartars  call  kirmitz.  About  a  pound 
of  the  dried  herb  tschagar.n,  which  grows 
in  great  abundance  in  the  neighbourhood 
of  Astracan,  and  is  a  kind  of  soda-plant 
orkali,  (salsola  ericoides,)  is  boiled  a  full 
hour  in  a  kettle  containing  about  four  com 
mon  pailfulls  of  water;  by  which  means 
the  water  acquires  a  greenish  colour.  The 
herb  is  then  taken  out,  and  about  half 
pound  of  pounded  cochineal  is  put  into  the 


kettle,  and  the  liquor  is  left  to  boil  a  full 
hour,  care  being  taken  to  stir  it  that  i'>. 
may  not  run  over.  About  fifteen  or  twenty 
drums  of  a  substance  which  the  dyers 
call  iuttr  (orchilla)  is  added,  and  when 
the  liquor  has  been  boiled  for  some  time 
longer  the  kettle  is  removed  from  the  tire. 
The  skins  taken  from  the  pickle  are  then 
placed  over  each  other  in  troughs,  and 
the  dye-liquor  is  poured  over  them  four 
different  times,  and  rubbed  into  them  with 
the  hands,  that  the  colour  may  be  equally 
imbibed  and  diffused.  The  liquor  each 
time  is  expressed ;  after  which  they  are 
fit  for  being  dried.  Skins  prepared  in 
this  manner  are  sold  at  a  much  dearer 
ate  than  any  of  the  other  kinds. 

Manufacture  of  Gun-powder.  See  Gun- 
powder. 

Manufacture  of  Hats—  Hats  are  made 
either  of  wool,  or  fur  of  different  animals, 
particularly  of  the  beaver,  rabbit,  and 
camel.  The  process  is  nearly  the  same 
in  all ;  it  will  therefore  be  sufficient  if  we 
describe  the  method  made  use  of  in  the 
manufacture  of  beaver  hats. 

The  skin  of  the  beaver  is  covered  with 
two  kinds  of  hair,  the  one  long,  stiff  and 
glossy  ;  the  other  is  short,  thick  and  soft, 
and  is  alone  used  for  hats. 

To  tear  off  one  of  these  kinds  of  hair, 
and  cut  the  other  a  large,  knife  some- 
thing  like  a  shoe-maker's  knife,  for  the 
long  hair;  and  a  smaller  one  nearly  in  the 
form  of  a  pruning  knife,  with  which  they 
shave  or  scrape  off  the  shorter  hair  are 
used. 

When  the  hair  is  off,  they  mix  and  card 
it ;  they  then  place  it  on  a  table  having 
slits  in  it  lengthwise  :  on  this  table  they 
mix  the  hair  together,  the  dust  and  filth 
falling  through  the  chinks  or  slits.  In 
this  manner  they  form  gores,  as  they  are 
called,  of  an  oval  shape,  and  with  the 
stuff  that  remains  they  supply  and 
strengthen  the  parts  that  may  be  slighter 
than  they  should  be.  In  that  part  of  the 
brim  which  is  next  the  crown,  the  sub- 
stance is  thicker  than  in  the  other  parts  of 
the  hat. 

The  gores  thus  finished,  the  workman 
goes  on  to  harden  them  into  closer  or 
more  consistent  flakes  by  pressure  ;  they 
are  then  carried  to  the  bason,  which  is 
a  sort  of  bench  with  an  iron  plate  in  it, 
and  a  little  fire  underneath  it ;  upon  this 
gores  are  laid,  sprinkled,  and  brought 
into  a  conical  shape  by  means  of  a  mould. 

The  hat  is  now  removed  to  a  large 
receiver  or  trough,  resembling  a  mill- 
hopper,  to  the  bottom  of  which  is  at- 
tached a  copper  kettle  filled  with  water 
and  grounds,  kept  hot  for  the  purpose. 


MAN 


MAN 


The  basoned  hat  is  first  dipped  in  the 
kettle,  and  then  worked  tor  several  hours, 
till  it  is  properly  thickened. 

The  Jiut  is  now  to  receive  its  due 
shape ;  which  is  done  by  laying-  the  coni- 
cal cap  on  a  wooden  block  of  the  size  of 
the  intended  crown,  tying1  it  down  fast 
with  a  piece  of  packthread  at  the  bottom 
of  the  block ;  after  which  it  is  singed,  and 
the  coarse  nap  is  taken  off,  first  with  a 
pumice-stone,  then  with  a  piece  of  seal- 
skin ;  and  lastly,  it  is  carded  with  a  fine 
card  to  raise  the  cotton,  with  which  the 
hat  is  afterwards  to  appear. 

When  the  hat  is  so  far  advanced,  it  is 
sent,  tied  with  the  packthread  on  its 
block,  to  be  dyed.  This  operation  is  per- 
formed by  boiling- 100  pounds  of  logwood, 
32  pounds  of  gum,  and  6  pounds  of  gall, 
in  a  proper  quantity  of  water  ;  after  which 
6  pounds  of  verdigrise,  and  10  pounds  of 
green  vitriol,  are  added,  and  the  liquor  is 
kept  simmering-.  Ten  or  twelve  dozen 
of  hats  are  immediately  put  in,  each  on 
its  block,  and  kept  down  by  cross  bars : 
for  about  an  hour  and  a  half:  they  are 
then  taken  out  and  aired,  and  the  same 
number  of  other  hats  put  in  their  rooms 
the  two  sets  of  hats  are  then  dipped  and 
aired  alternately  several  times  each,  the 
liquor  being-  refreshed  each  time  with 
more  ingredients. 

The  dye  being-  complete,  the  hatter 
bang's  it  in  the  roof  of  a  stove  or  oven,  at 
the  bottom  of  which  is  a  charcoal  fire : 
when  dry  it  is  to  be  stiffened,  which  is 
done  by  melted  g-lue  or  gum.  It  is  then 
to  be  steamed  on  the  steaming- -bason, 
which  is  a  little  hearth  or  fire-place,  raised 
three  feet  high,  with  an  iron-plate  laid 
over  it,  on  which  cloths,  moistened  with 
water,  are  laid,  to  secure  the  hat  fgbm 
burning-.  This  operation  is  done  entirely 
by  the  hand. 

When  steamed  and  dried,  it  is  put  again 
on  the  block,  and  brushed  and  ironed,  on 
a  table  or  bench,  called  the  stall-board, 
till  it  receives  "the  gloss  which  all  new 
hats  have.  The  edges  are  then  clipped 
very  smooth  and  even,  and  the  lining 
sewed  into  the  crown. 

In  Nicholsons  Journal,  vol  1st,  2d,  and 
3d,  4to.  the  art  of  hat  making  is  fully  de- 
scribed. 

A  patent  was  granted  in  January  1782, 
to  MEr.  Robert  Golding,  of  South wark, 
hat-  Iyer,  for  his  method  of  dyeing,  stain- 
ing, and  colouring  beaver  hats  green,  or 
any  other  colour— The  inventor  directs 
the  nap  of  the  hat  to  be  raised  by  means 
of  a  card,  on  the  side  intended  to  be  dyed, 
and  then  boiled  in  alum  and  argol.  A 
thin  paste  should  be  made  of  flour,  or 
VOL.  II. 


clay,  which  is  spread  over  every  part  that 
is  not  to  be  dyed,  and  then  closed  ;  or  the 
hat  may  be  previously  pasted,  and  instead 
of  being  boiled,  it  should  be  only  sim- 
mered in  the  same  liquor.  As  soon  as 
the  paste  is  spread,  plates  of  copper  of 
other  metal,  shaped  like  a  common  funnel, 
are  fixed  over  the  paste,  to  prevent  the 
dye  from  penetrating  through.  In  this 
state,  the  hat  is  immersed  in  the  dye,  till 
the  colour  be  sufficiently  fixed ;  when  it 
is  taken  out,  opened,  and  cleansed  from 
the  paste  :  but,  if  any  colouring  particles 
have  penetrated  through  the  felt,  they 
may  be  removed  by  rubbing  them  with  a 
small  quantity  of  spirit  of  salt,  aqua  fortis, 
Sec.  The  compounds  employed  in  dyeing, 
are  fustic,  turmeric,  ebony,  saffron,  alum, 
argol,  indigo,  and  vitriol,  with  urine,  or 
pearl-ash,  at  the  option  of  the  dyer ;  all  of 
which  are  used  together,  or  separately, 
according  to  the  colour  required. 

Among  the  different  patents  granted  to 
hatters,  for  discovering  new  materials  in 
this  manufacture,  such  as  that  of  Mr.  J. 
Burn,  in  1792,  for  mole -fur  ;  and  anothef 
to  Mr.  J.  Tilstone,  in  1794",  for  kid-hair  ; 
we  shall  only  notice  an  invention  of  Mr. 
George  Dunnage,  wTho,  in  November  1794, 
obtained  a  patent  for  his  Water-proof 
Hats,  in  imitation  of  beaver.  * 

The  articles  he  employs  are  similar  to 
those  commonly  used  for  the  making  of 
hats,  with  which  he  mixes  Bergam,  Pied- 
mont, or  Organ zine  silk.  These  are  dress- 
ed and  worked  in  a  peculiar  manner ; 
though  we  understand  that  hats  thus  pre- 
pared become  heavy  and  oppressive  to 
the  wearer,  while  they  acquire  an  ugly 
colour — The  curious  reader  will  find  the 
patentee's  specification  inserted,  at  full 
length,  in  the  4th  vol.  of  the  Repertory  of 
Arts  and  Manufactures.  The  same  manu- 
facturer procured  another  patent  in  No- 
vember 1798,  for  a  method  of  ventilating 
the  crowns  of  hats.  This  invention  con- 
sists in  separating  the  top  from  the  sides 
of  the  crown,  so  that  the  tip,  or  top 
crown,  may  be  either  raised  or  let  down 
at  pleasure,  in  order  to  admit  the  external 
air,  or  to  exclude  it  from  circulating  in 
the  crown  of  the  hat.  The  whole  con- 
trivance is  effected  by  means  of  springs, 
sliders,  sockets,  grooves,  loops,  and  cases, 
which  are  connected  with  the  top  and 
side-crown  :  thus  the  admission  or  exclu- 
sion of  atmospheric  air  in  front,  behind, 
or  on  either  side,  may  be  regulated  ac- 
cordingly— As  this  invention  is  ingenious, 
we  refer  the  reader  to  the  10th  vol.  of  the 
work  last  quoted,  where  he  will  find  a 
minute  account,  illustrated  by  an  engrav- 
ing. 

T 


MAN 


MAN 


In  November,  1801,  a  patent  was  ob- 
tained by  Messrs.  John  Walker  and 
Peter  Alphey,  for  contriving-  water-proof 
hats  and  caps,  as  likewise  for  rendering 
silk,  linen,  leather,  cotton,  and  other 
materials  for  wearing-  apparel,  water- 
proof— Their  invention  consists  in  provid- 
ing the  respective  articles  with  a  coat  of 
oil-paint;  after  which  they  are  japanned 
with  a  varnish  mixed  vvitli  lamp  or  ivory- 
black.  The  caps  and  hats  are  manufac- 
tured of  paste-board  covered  with  canvas, 
and  treated  in  a  similar  manner ;  but  the 
leather,  to  be  made  water-proof,  should 
not  be  previously  dressed  with  oil,  or 
any  unctuous  matter — For  a  more  minute 
account  of  the  method  in  which  the  dif- 
ferent compositions  are  applied,  the  rea- 
der will  consult  the  16th  vol.  of  the  "  Re- 
pertory of  Arts,"  &c. 

Manufacture  of  Indigo.    See  Indigo. 

Manufacture  of  Ink.    See  Ink. 

Manufacture  of  Isinglass.  See  Gela- 
tin. 

Manufacture  of  Lakes.  See  Lakes  and 
Colour-Making. 

Manufacture  of  Lead,  or  Plumbing — The 
business  of  the  plumber  consists  in  the  art 
of  casting  and  working  of  lead,  and  using 
it  in  buildings.  He  furnishes  us  with  a  cis. 
tern  for  water,  and  with  a  sink  for  the  kitch- 
en ;  he  covers  the  house  with  lead,  and 
makes  the  gutters  to  carry  away  the  rain- 
water ;  he  makes  pipes  of  all  sorts  and  si- 
zes, and  sometimes  he  casts  leaden  sta- 
tues as  ornaments  for  the  garden.  The 
plumber  also  is  employed  in  making  cof- 
fins for  those  who  are  to  be  interred  out 
of  the  common  way.  And  besides  these 
departments  in  his  trade,  the  modern 
plumber  makes  no  small  share  of  his  pro- 
fits by  laying  pipes  and  introducing-  water 
into  our  "houses.  Of  these  there  are  many 
different  kinds,  and  but  few  inventions  in 
modern  days  have  answered  so  well  as 
these. 

The  chief  articles  in  plumbery  consist- 
ing in  sheets  and  pipes  of  lead,  we  shall 
briefly  describe  the  processes  of  making 
them. 

In  casting  sheet-lead,  a  sort  of  table,  or 
mould,  is  used,  about  four  or  five  feet  wide, 
and  sixteen  or  eighteen  feet  long;  it  must 
slope  a  little  from  the  end  in  which  the 
metal  is  poured  on,  and  the  slope  must  be 
greater  in  proportion  to  the  thinness  of 
the  lead  wanted.  The  mould  is  spread 
over  with  moistened  sand  about  two 
inches  thick,  and  made  perfectly  smooth 
by  means  of  a  piece  of  wood  called  a  strike. 
At  the  upper  end  of  the  mould  is  a  pan  of 
a  triangular  shape.  The  lead,  being  melt- 
ed, is  put,by  means  of  ladles,  into  this  pan; 


and  when  it  is  cool  enough,  two  men  take 
the  pan  by  the  handle,  (or  else  one  of  them 
lifts  it  by  a  bar  and  chain  fixed  to  the 
beam  in  the  cieling,)  and  pour  it  into  the 
mould,  while  another  man  stands  ready 
with  the  strike  to  sweep  the  lead  forward, 
and  draw  the  overplus  into  a  trough  rea- 
dy to  receive  it.  The  sheets  being  thus 
cast,  it  remains  only  to  roll  them  up  or  cut 
them  to  any  particular  size. 

If  a  cistern  is  wanted,  they  measure  out 
the  four  sides,  and  form  any  figures  intend- 
ed to  be  raised  on  the  front  in  the  sand, 
and  cast  as  before  ;  the  sides  are  then  sol- 
dered together,  after  which  the  bottom  is 
soldered  in. 

Pipes  are  cast  in  a  kind  of  mill,  with 
arms  or  levers  to  turn  it.  The  moulds  are 
of  hollow  brass,  consisting  of  two  pieces, 
about  two  feet  and  a  half  long,  which 
open  and  shut  by  means  of  hinges  and 
hooks.  In  the  middle  of  these  moulds  is 
placed  a  core  or  round  solid  piece  of  brass 
or  iron,  somewhat  longer  than  the  mould. 
This  core  is  passed  through  two  copper 
rundles,  one  at  each  end  of  the  mould, 
which  they  serve  to  close  ;  to  these  is 
joined  a  little  copper  tube  two  inches 
long,  and  of  the  thickness  of  the  intended 
leaden  pipe.  These  tubes  retain  the  core 
exactly  in  the  middle  of  the  cavity  of  the 
mould,  and  then  the  lead  is  poured  in 
through  an  aperture  in  the  shape  of  a  fun- 
nel. WKen  the  mould  is  full,  a  hook  is 
put  into  the  core,  and,  turning  the  mill,  it 
is  drawn  out,  and  the  pipe  is  made.  If  it 
is  to  be  lengdiened,  they  put  one  end  of  it 
in  the  lower  end  of  the  mould,  and  the  end 
of  the  core  into  it,  then  shut  the  mould 
again,  and  apply  its  rundie  and  tube  as 
before,  the  pipe  just  cast  serving  for  a 
rundie,  &c-  at  the  other  end.  Metal  is 
again  poured  in  which  unites  with  the 
other  pipe,  and  so  the  operation  is  repeat- 
ed till  the  pipe  is  of  the  length  required. 

Large  pipes  of  sheet-lead  are  made  by 
wrapping  the  lead  on  wooden  cylinders  of 
the  proper  length,  and  then  soldering  it 
up  the  edges.    See  Lead. 

Manufacture  of  Leather.    See  Leather. 

Manufacture  of  Marine  Acid.  See  Mu- 
riatic Acid. 

Manufacture  of  Morocco  Leather.  See 
Leather. 

Manufacture  of  Oil  of  Vitriol.  See  Sul- 
phuric Acid. 

Manufacture  of  Paints.    See  Colours. 

Manufacture  of  Paper     See  Paper. 

Manufacture  of  Paper  Hangings.  See 
Paper- 

Manufacture  of  Parchment.  See  Parch- 
ment. 

Manufacture  of  Pewter.    See  Tin. 


MAN 


MAN 


JWanufacsure  of  Pins  and  Needles. — 
There  is  scarcely  any  commodity  cheaper 
than  pins,  and  but  few  that  pass  through 
more  hands  before  they  come  to  be  sold 
It  is  reckoned  that  twenty-five  workmen 
are  successively  employed  in  each  pin,  be- 
tween the  drawing  of  the  brass  wire  and 
the  sticking-  of  the  pin  in  the  paper. 

It  is  not  easy  to  trace  the  invention  of 
this  very  useful  little  implement ;  it  is  first 
noticed  in  the  English  statute  book  in  the 
year  1483,  prohibiting-  foreign  manufac- 
tures :  and  it  appears  from  the  manner  in 
which  pins  are  described  in  the  reign  of 
the  British  king  Henry  the  VHIth,  and  the 
labour  and  time  which  the  manufacture 
of  them  would  require,  that  they  were  a 
new  invention  in  England,  and  probably 
brought  from  France. 

At  this  period  pins  were  considered  in 
Paris  as  articles  of  luxury ;  and  no  master 
pin-maker  was  allowed  to  open  more  than 
one  shop  for  the  sale  of  his  wares,  except 
on  New-year's  day,  and  the  day  before 
that :  it  should  seem,  therefore,  that  pins 
were  given  away  as  New-year's  gifts; 
hence  arose  the  phrase  pin-money,  the 
name  of  an  allowance  frequently  made  by 
the  husband  to  his  wile  for  her  own 
spending. 

Pins  are  now  made  wholly  of  brass 
wire ;  formerly  iron  wire  was  made  use  of, 
but  the  ill  effects  of  iron  have  nearly  dis- 
carded that  substance  from  the  pin-manu- 
factory. The  excellence  and  perfection 
of  pins  consist  in  the  stiffness  of  the  wire, 
and  its  blanching;  in  the  heads  being  well 
turned,  and  the  points  accurately  filed. 
The  following  are  some  of  the  principal 
operations. 

When  the  brass  wire,  of  which  the  pins 
are  formed,  is  first  received,  it  is  general- 
ly too  thick  for  the  purpose  of  being  cut 
into  pins.  It  is  therefore  wound  off  from 
one  wheel  to  another,  with  great  velocity, 
and  made  to  pass  between  the  two, 
through  a  circle  in  a  piece  of  iron  of  small- 
er diameter.  The  wire  is  then  straight- 
ened, and  afterwards  cut  into  lengths  of 
three  or  tour  yards,  and  then  into  smaller 
ones,  every  length  being  sufficient  to  make 
six  pins  ;  each  end  of  these  is  ground  to  a 
point,  which  is  performed  by  a  boy,  who 
sets  with  two  small  grinding-stones  before 
him,  turned  by  a  wheel.  Taking  up  a 
handful,  he  applies  the  ends  to  the  coars- 
est of  the  two  stones,  being  careful  at  the 
same  time  to  keep  each  piece  moving 
round  between  his  fingers,  so  that  the 
points  may  not  become  flat :  he  then  gives 
them  to  the  other  stone ;  and  by  that 
means  a  lad  of  twelve  or  fourteen  years  of 
age  is  enabled  to  point,  about  16,000  pins 


in  an  hour.  When  the  wire  is  thus  point' 
ed,  a  pin  is  taken  off  from  each  end,  and 
this  is  repeated  till  it  is  cut  into  six  pieces. 
The  next  operation  is  that  of  forming  the 
heads,  or,  as  they  term  it,  head  spinning  ; 
which  is  done  by  means  of  a  spinning- 
wheel,  one  piece  of  wire  being  thus,  with 
astonishing  rapidity,  wound  round  anoth- 
er, and  the  interior  one  being  drawn  out, 
leaves  a  hollow  tube ;  it  is  then  cut  with 
shears,  every  two  turns  of  the  wire  form- 
ing one  head ;  these  are  softened  by  throw- 
ing them  into  iron  pans,  and  placing  them 
in  a  furnace  till  they  are  red-hot.  As  soon 
as  they  are  cool,  they  are  distributed  to 
children,  who  sit  with  their  anvils  and 
hammers  before  them,  which  they  work 
with  their  feet,  by  means  of  a  lathe ;  and 
taking  up  one  of  the  lengths,  they  thrust 
the  blunt  end  into  a  quantity  of  the  heads 
that  lie  before  them,  and  catching  one  at 
the  extremity,  they  apply  them  immedi- 
ately to  the  anvil  and  hammer,  and  by  a 
motion  or  two  of  the  foot,  the  point  and 
the  head  are  fixed  together  in  much  less 
time  than  it  can  be  described  in,  and  with 
a  dexterity  only  to  be  acquired  by  prac- 
tice, the  spectator  being  in  continual  ap- 
prehension for  the  safety  of  their  fingers' 
ends. 

The  pin  is  now  finished  as  to  its  form, 
but  still  it  is  merely  brass  ;  for  which  pur  - 
pose it  is  thrown  into  a  copper  containing 
a  solution  of  tin  and  the  leys  of  wine. 
Here  it  remains  for  some  time ;  and  when 
taken  out  it  assumes  a  white  though  dull 
appearance.  To  give  it  a  polish,  it  is  put 
into  a  tub  containing  a  quantity  of  bran, 
which  is  set  in  motion  by  turning  a  shaft 
that  runs  through  its  centre,  and  thus  by- 
means  of  friction  it  becomes  perfectly 
bright.  The  pin  being  complete,  nothing 
remains  but  to  separate  it  from  the  bran, 
which  is  performed  by  a  mode  exactly  si- 
milar to  the  winnowing  of  corn,  the  bran 
flying  off,  and  leavingthe  pin  behind  fit 
for  immediate  sale. 

The  pins  most  esteemed  in  commerce 
are  those  of  England;  those  of  Bordeaux 
are  next ;  then  those  made  in  some  of  the 
other  departments  of  France.  The  Lon- 
don pointing  and  blanching  are  most 
in  repute,  because  they,  in  pointing,  use 
two  steel  mills,  the  first  of  which 
forms  the  point,  and  the  latter  takes  off  all 
irregularities,  and  renders  it  smooth,  and, 
as  it  were,  polished ;  and  in  blanching  they 
use  block-tin,  granulated ;  whereas,  in 
other  places  they  mix  their  tin  with  lead 
and  quicksilver,  which  not  only  blanches 
worse  than  the  former,  but  is  also  danger- 
ous, as  any  puncture  made  with  pins  of 
this  sort  is  not  so  readily  cured. 


MAN 


MAN 


Pins  are  distinguished  by  numbers ;  the 
smaller  are  called  fi  om  No  3,  4,  5,  to  the 
14th,  whence  they  go  by  two's,  Xo.  16,  18, 
and  20,  which  is  the  largest  sire.  Besides 
the  white  pins,  there  are  black  ones,  made 
for  the  use  of  mourning,  from  No.  4  to  No 
10.  Pins  are  also  distinguished  by  weight, 
as  4  lb.  pins,  4^  lb.  pins,  5  lb.  pins — mean- 
ing 4  lb.  to  the  thousand — 4J  lb.  to  the 
thousand — 5  lb.  to  the  thousand  There 
are  pins  with  double  heads  of  several 
numbers,  used  by  ladies  to  fix  the  buckles 
of  their  hair  for  the  night,  without  the 
danger  of  pricking. 

The  tinning  of  brass  pins  may  be  per- 
formed by  boiling  them  between  plates 
of  sheet  tin,  or  tin  plate,  in  a  solution  of 
cream  of  tartar.  A  manufactory  of  pins 
has  been  established  at  Boston.  During 
the  Revolution,  they  were  made  in  Phi- 
ladelphia. 

We  shall  now  give  a  short  account  of 
the  manufacture  of  needles  :  these  make 
a  very  considerable  article  in  commerce  : 
the  consumption  of  them  is  almost  incre- 
dible. The  sizes  are  from  No.  1,  the  lar- 
gest, to  No.  25,  the  smallest.  In  the  ma- 
nufacture of  needles,  the  German  and 
Hungarian  steel  are  in  the  most  re- 
pute. 

The  first  thing  in  making  needles  is,  to 
pass  the  steel  through  a  coal  fire,  and  by 
means  of  a  hammer  to  bring  it  into  a  cy- 
lindrical form.  This  being  done,  it  is 
drawn  through  a  large  hole  of  a  wire- 
drawing iron,  and  returned  into  the  fire, 
and  drawn  through  a  second  hole  of  the 
iron  smaller  than  the  first,  and  so  on  till  it 
has  acquired  the  degree  of  fineness  re- 
quired tor  that  species  of  needles.  The 
steel,  thus  reduced  to  a  fine  wire,  is  cut 
in  pieces  of  the  length  of  the  needles  in- 
tended. These  pieces  are  flatted  at  one 
end  on  the  anvil,  in  order  to  form  the 
head  and  eye.  They  are  then  softened 
and  pierced  at  each  extreme  of  the  flat 
part,  on  the  anvil,  by  a  punch  of  well- 
tempered  steel,  and  hud  on  a  leaden  block 
to  bring  out,  with  another  punch,  the  lit- 
tle piece  of  steel  remaining  in  the  eye. 
When  the  head  and  eye  are  finished,  the 
point  is  formed  with  a  file,  and  the  whole 
filed  over  :  they  are  then  laid  to  heat  red 
hot  on  a  long  narrow  iron,  crooked  at  one 
end,  in  a  charcoal  fire ;  and  when  taken 
out  thence,  they  are  thrown  into  a  bason 
of  cold  water  to  harden.  They  are  then 
laid  in  an  iron  shovel  on  a  fire  more  or 
less  brisk  in  proportion  to  the  thickness  of 
the  needles,  taking  care  to  move  them 
from  time  to  time  This  serves  to  temper 
them,  and  >ake  off  their  brittleness.  They 
are  now  to  be  straightened,  one  after  ano- 
ther, with  the  hammer. 


The  next  process  is  the  polishing.  To 
do  this  they  take  twelve  or  fifteen  thou- 
sand needles,  and  range  them  in  little 
heaps  against  each  other  on  a  piece  of 
new  buckram  sprinkled  with  emery-dust. 
The  needles  being  thus  disposed,  emery- 
dust  is  thrown  over  them,  which  is  again 
sprinkled  with  oil  of  olives;  at  last  the 
whole  is  made  up  into  a  roll,  well  bound 
at  both  ends.  This  roll  is  laid  on  a  po- 
lishing-table,  and  over  it  a  thick  plank 
loaded  with  stones,  which  men  work  back- 
wards and  forwards  for  two  days  succes- 
sively :  by  these  means  the  needles  be- 
come insensibly  polished.  They  are  now 
taken  out,  and  the  filth  washed  oft'  with 
hot  water  and  soap  :  they  are  then  wiped 
in  hot  bran,  a  little  moistened,  placed 
with  the  needles  in  a  round  box,  suspend- 
ed in  the  air  by  a  cord,  which  is  kept 
stirring  till  the  bran  and  needles  are  dry. 
The  needles  are  now  sorted  ;  the  points 
are  turned  the  same  way,  and  smoothed 
with  an  emery  stone  turned  with  a  wheel ; 
this  is  the  end  of  the  process,  and  nothing 
remains  to  be  done  but  to  make  them  up 
in  packets  of  250  each. 

Needles  were  first  made  in  England,  by 
a  native  of  India,  in  1545,  but  the  art  was 
lost  at  his  death  :  it  was,  however,  shortly 
after  recovered  by  Christopher  Greening, 
who,  with  his  three  children,  were  settled 
by  Mr.  Darner,  ancestor  of  the  present 
Lord  Milton,  at  Long  Crendon,in  Bucks, 
where  the  manufactory  has  been  carried 
on  from  that  lime  to  the  present. 

In  order  to  preserve  needles  from  rust, 
they  may  be  sprinkled  with  whiting,  or  if 
rusted,  may  be  passed  through  a  small 
bag  containing  powdered  emery. 

Manufacture  of  Saws. — Mr.  Arnold 
Wilde,  and  Mr  Joseph  Ridge,  of  Great 
Britain;  have  obtained  a  patent  for  making 
and  manufacturing  different  kinds  of 
saws,  &c. 

This  invention  is  described  as  follows 
— Our  said  invention  of  making  and  ma- 
nufacturing all  kinds  of  saws,  steel  doctors 
for  printers,  plates  made  of  iron,  also,  of 
steel,  beads,  mouldings,  and  fender  plates 
made  of  iron  and  steel  united,  or  of  iron 
or  steel,  and  all  sorts  of  springs  made  of 
steel,  and  divers  other  articles  made  of 
iron  and  steel  united,  and  also  of  iron  or 
steel,  is  particularly  described  and  ascer- 
tained in  manner  following  ;  that  is  to  say  : 
When  the  steel  or  iron  is  pared  or  cut  into 
proper  shape,  the  saws,  doctors  for  prin- 
ters, plates  of  iron  or  steel,  beads,  mould- 
ings, and  fender  plates,  whether  made  of 
iron  and  steel  united,  or  of  iron  or  steel, 
and  all  sorts  of  springs  made  of  steel,  and 
divers  other  articles  made  of  iron  and 
steel  united,  and  also  of  iron  or  steel,  are 


MAN 


MAN 


put  into  a  frame  of  metal,  or  otherwise  1 
they  may  then  be  made  red-hot  in  the  said 
frame,  and  stretched  by  screw,  spring1, 
weight,  or  any  other  proper  power  or 
purchase,  and  so  formed  into  a  curved, 
straight,  or  any  other  direction  wanted. 
They  are  then  to  be  immersed  in  water,  or 
a  composition  of  oils  or  grease,  to  be 
hardened  in  the  frame  in  the  direction 
wanted ;  and  when  so  hardened  they  are 
also  to  be  tempered  in  the  same  direction 
in  the  frame  over  fire  :  and  when  the  saw, 
doctor  for  printers,  or  plate,  is  over  the 
fire,  it  must  be  kept  in  motion  until 
the  oil  or  grease  upon  the  said  saw, 
doctor,  or  plate,  smokes.  It  is  then 
to  be  gently  stretched,  and  continually 
kept  moving  over  the  fire  until  a  blue 
blaze  alternately  appears  and  disappears. 
It  is  then  to  be  stretched  with  as  much 
power  as  will  bring  it  into  the  direction 
required.  The  saw,  doctor,  or  plate,  is 
next  to  be  put  into  another  frame,  which 
may  be  made  to  move  upwards  and  down- 
wards, or  in  any  other  direction  necessa- 
ry, by  crank,  or  any  other  movement,  be- 
tween proper  stones,  or  between  plates  of 
metal,  blocks  of  wood,  or  any  other  ma- 
terial that  will  grind  or  polish  with  sand, 
emery,  or  other  proper  material  to  grind 
and  polish  the  saws,  steel  doctors  for 
printers,  plates  made  of  iron,  also  of  steel, 
heads,  mouldings,  and  fender  plates, 
made  of  iron  and  steel  united,  or  of  iron  or 
steel,  and  all  sorts  of  springs  made  of 
steel,  and  divers  other  articles  made  of 
iron  and  steel  united,  and  also  of  iron  or 
steel.  But  if  the  saw,  doctor,  or  plate,  is 
not  intended  to  be  hardened,  it  must  be 
made  red  hot,  and  stretched  with  as  much 
j)ower  as  will  bring  it  into  the  direction 


wanted ;  it  must  then  lie  in  the  open  air 
in  the  frame,  in  the  said  direction  requii 
ed,  till  cold :  then  to  be  ground  by  a  ma- 
chine for  the  purpose  of  grinding  and  po- 
lishing in  a  frame  the  said  saws,  steel  doc- 
tors for  printers,  plates  made  of  iron,  also 
of  steel,  beads,  mouldings,  and  fender 
plates,  made  of  iron  and  steel  united,  or 
of  iron  or  steel,  and  all  sorts  of  springs  j 
made  of  steel,  and  divers  other  articles 
made  of  iron  and  steel  united,  and  also  of 
said  saw,  doctor,  or  plate,  by  means  of  a  j 
crank,  or  otherwise,  as  before  expressed 
•Manufacture  of  Malt. — In  addition  to 
the  remarks  heretofore  made,  on  the  pre- 
paration of  malt,  we  have  given  the  fol- 
lowing as  a  sketch  of  the  improved  kiln, 
invented  by  Mr.  Barrett. 

Air  tubes  are  fixed  in  such  a  man- 
ner that  the  air,  heated  by  passing  round 
the  neck  of  the  kiln,  can  be  made  either 
to  pass  out  above  or  below  the  malt  at 
pleasure  :  this  contrivance,  Mr.  Barrett 


says,  effectually  carries  off* the  great  quan- 
tity of  steam  which  is  generated  in  dry- 
ing the  malt ;  and  is  particularly  service- 
able in  the  process  of  drying  pale  malt : 
the  extremities  of  the  above  passages  are 
closed  with  iron  lattice  to  hinder  vermin 
from  entering. 

To  prevent  the  absorption  of  heat,  the 
walls  of  the  kiln  are  built  hollow,  or  with 
hollow  passages  in  them,  at  every  side  ; 
the  floor  of  the  ash-pit,  and  the  whole  area 
on  which  the  kiln  stands,  is  laid  on  arch- 
es for  the  same  purpose. 

The  regulator  for  closing  the  upper 
part  of  the  kiln  consists  of  four  sheet  iron 
quadrants,  which  turning  on  pivots  in  the 
line  of  the  middle  radius  of  each,  in  such 
manner,  that  when  in  a  horizontal  position, 
they  form  a  completely  close  disk,  which 
stops  the  whole  of  the  aperture,  and  when 
in  a  vertical  position  they  leave  it  entirely 
open;  in  all  intermediate  positions,  they 
leave  a  passage  for  the  heated  air  to  pass 
out  proportionate  to  their  degree  of  incli- 
nation, and,  when  so  placed,  resemble 
much  the  fliers  of  a  smoke-jack;  a  wire 
passes  from  each  quadrant  a  little  way 
down  and  hooks  to  another  wire  or  chain, 
common  to  all  four,  which  passes  down 
to  the  front  of  the  fire-place,  and  by  pull- 
ing which  the  workmen  can  close  the  up- 
per aperture  to  any  degree  he  chooses ;  it 
may  be  easily  conceived  how,  on  letting 
go  the  wire,  the  quadrants  could  be  con- 
trived to  open,  by  having  weights  so  fixed 
to  them,  as  to  make  them  preponderate 
at  one  side  of  their  centres  of  motion. 

This  regulator  will  at  once  extinguish 
all  accidental  fires  in  the  kiln  ;  will  econo- 
mize heat  in  preventing  the  access  of  cold 
air  downwards  on  the  malt  when  the  dry- 
ing first  commences  (which  will  be  parti- 
cularly useful  in  drying  pale  malt)  and, 
by  being  closed  when  the  kiln  is  not  in 
use,  will  protect  the  kiln-wire,  or  hair 
cloth,  from  damage  by  the  weather,  or 
soil  from  birds. 


The  moveable  furnace  is  of  an  oblong- 
shape,  and  is  constructed  with  a  fire- 
chamber,  and  ash-pit,  with  doors  and  re- 
gisters in  the  same  manner  as  a  chymical 
furnace ;  there  is  a  damper  annexed  to  it, 
so  contrived  that,  by  moving  it  to  a  certain 
degree,  a  new  passage  is  opened  for  the 
fire  into  the  iron  flue  next  to  be  describ- 
ed, and  the  direct  passage  to  the  malt 
closed. 

The  use  of  this  iron  flue  (which  forms 
the  fourth  principal  contrivance)  is  to  per- 
mit the  burning  of  common  coal  for  heat- 
ing the  kiln,  when  culm  or  coke  cannot 
easily  be  had  It  consists  of  a  flue  of  cast- 
iron,  through  which  the  smoke  passes  in- 
to a  chimney,  around  which  another  tube 


MAN 


MAN 


is  made  to  pass  spirally,  one  extremity  of 
which  communicates  with  the  space  be- 
neath the  frame  for  sustaining  the  malt, 
and  tne  other  is  connected  with  pipes 
passing  through  the  body  of  the  fire  (or 
where  they  will  receive  considerable  heat 
from  it)  to  the  external  air.  By  this  means 
the  air  is  heated  so,  in  circulating  round 
the  iron  flue,  as  to  dry  the  malt  effectually, 
and  at  the  same  time  be  totally  separated 
from  the  smoke. 

Mr.  Barrett  recommends  the  use  of  iron 
In  the  formation  of  the  cowl,  of  the  inter- 
nal doors,  and  of  the  window  frames,  as 
being  not  liable  to  warp  or  shrink,  and 
free  from  danger  of  burning. 

Besides  these  contrivances,  Mr.  Barrett 


into  wire.  The  mill  consists  of  a  steei 
plate,  perforated  with  holes  of  different 
dimensions,  and  a  wheel  which  turns  the 
spindles.  The  ingot,  which  at  first  is  but 
small,  is  passed  through  the  largest  hole, 
and  then  through  one  a  degree  smaller, 
and  so  continued  till  it  is  drawn  to  the 
required  fineness  ;  and  it  is  all  equally 
gilt,  if  drawn  out  as  fine  as  a  hair. 

The  next  operation  is  that  of  the  flatting 
mill,  which  consists  of  two  perfectly  round 
and  exquisitely  polished  rollers,  formed 
internally  of  iron,  and  welded  over  with 
a  plate  of  refined  steel  ;  these  rollers  are 
placed  with  their  axes  parallel  and  their 
circumferences  nearly  in  contact ;  they 
/  are  both  turned  with  one  handle  ;  the 


mentions  two  ^  doors  of  iron  or  earthen  'lowermost  is  about  ten  inches  in  diameter, 

the  upper  about  two,  and  they  are  some- 
,  thing  more  than  an  inch  in  thickness, 
the  kiln,  to  equalize  the  flame  arising  '  The  wire  unwinding  from  a  bobbin,  and 


ware,  moveable  at  pleasure,  placed  at 
each  side  at  the  further  end  of  the  neck  of 


from  wood,  in  drying  brown  malt,  whicl 


i  1  passing  between  the  leaves  of  a  book 


seems  to  be  particularly  useful :  as  Mr.  I  gentlv  pressed,  and  through  a  narrow  slit 


Barrett  says  this  object  cannot  be  obtain 


m  an  upright  piece  of  wood,  called  a  ketch, 
a 


eel  by  any  skill  or  labour  of  the  workmen,  is  directed  by  a  small  conical  hole  in  a 
id  kilns  of  the  old  construction,  but  of '  piece  of  iron,  called  a  guide,  to  any  par 


which  he  has  ^unfortunately  given  no  ac- 
curate description  either  as  to  their  size, 
position,  or  management. 

Manufacture  of  Shagreen.  See  Leather. 

Manufacture  of  Shot.  See  Lead. 

Manufacture  of  Soap.  See  Soap. 

Manufacture  of  Spirits.  See  Spirit,  Al- 
cohol, &c. 

Manufacture  of  Starch  See  Starch. 

Manufacture  of  Steel.  See  Iron. 

Manufacture  of  Sugar.  See  Sugar. 

Manufacture  of  Tin-plate.    See  Iron. 

Manufacture,  of  Verdigrease.  See  Cop- 
per. 

Manufacture  of  Vinegar.  See  Vinegar. 

Manufacture  of  Wine.  See  Wine. 

Manufacture  of  Wire. — The  manufac- 
ture of  wire  of  iron,  silver,  gold,  brass, 
&c.  for  different  purposes,  has  been  car- 
ried on  to  some  extent  in  the  United 
States. 

Metal  wires  are  frequently  drawn  so 
fine  as  to  be  wrought  with  other  threads. 


ticular  part  of  the  width  of  the  rollers, 
some  of  which  are  capable  of  receiving, 
by  this  contrivance,  forty  threads.  When 
the  wire  is  flatted  between  the  rollers,  it 
is  wound  again  on  a  bobbin,  which  is  turn- 
ed by  a  wheel,  fixed  on  the  axis  of  one  of 
the  rollers,  and  so  proportioned,  that  the 
motion  of  the  bobbin  just  keeps  pace  with 
that  of  the  rollers. 

Brass  and  copper  wire  is  drawn  in  a 
similar  manner  to  that  already  described. 
Of  the  brass  wire  there  are  many  different 
sizes,  suited  to  different  kinds  of  works. 
The  finest  is  used  for  the  strings  of  musi- 
cal instruments.  Pin-makers  also  use 
great  quantities  of  wires  of  several  sizes 
to  make  pins  of. 

Iron  wire  is  made  from  bsrs  of  iron, 
which  are  first  drawn  out  to  a  greater 
length,  to  about  the  thickness  of  half  an 
inch  in  diameter,  at  a  furnace  with  a  ham- 
mer gently  moved  by  water.  These  thin- 
ner pieces  are  bored  round,  and  put  into 


of  silk,  wool,  or  hemp;  and  thus  they  a  furnace  to  anneal.    A  very  strong  fire  is 


become  a  considerable  article  in  the  ma- 
nufactures. The  metals  most  commonly 
drawn  into  wire  are  gold,  silver,  copper, 
and  iron. 

Silver  wire  and  gold  wire  are  manufac- 
tured in  the  same  manner,  except  that  the 
latter  is  covered  with  gold.  There  are 
also  counterfeit  gold  and  silver  wires, 
made  of  copper  gilt  and  silvered  over. 

The  business  of  a  wire -drawer  is  thus 
performed  :  if  it  is  gold  wire  that  is  want- 
ed, an  ingot  of  silver  is  double  gilt,  and 
then  by  the  assistance  of  a  mill  it  is  drawn 


necessary  for  this  operation. 

They  are  then  delivered  to  the  workmen 
called  rippers,  who  draw  them  into  wire 
through  two  or  three  holes,  and  then  they 
arc  annealed  a  second  time;  after  which  they 
are  to  be  drawn  into  wire  of  the  thickness 
of  a  pack  thread :  after  this  they  are  again 
to  be  annealed,  and  then  delivered  to  the 
small-wire-drawers.  The  plate,  in  which 
the  holes  are,  is  iron  on  the  outside  and 
steel  on  the  inside  surface,  and  the  wire 
is  anointed  with  oil,  to  make  it  run  the 
easier.    The  first  iron  that  runs  from  the 


MAN 


MAN 


ore,  when  melting",  being  the  softest  and 
toughest,  is  usually  preserved  to  make 
wire  of. 

It  is  difficult  to  determine  the  period 
when  attempts  were  first  made  to  draw 
into  threads  metal  cut  or  beat  into  small 
slips,  by  forcing-  them  through  holes  in 
a  steel  plate.  It  should  appear  that  as  long 
as  the  work  was  performed  by  the  ham- 
mer, the  artists  at  Nuremberg  were  called 
wire-smiths;  but  after  the  invention  of 
drawing  iron,  they  were  denominated 
wire-drawers,  or  wire-millers.  Both  these 
appellations  occur  in  history  so  early  as 
the  year  1351 ;  therefore  the  invention 
must  have  been  known  in  the  fourteenth 
century. 

At  first,  threads  exceedingly  massy 
were  employed  for  weaving  and  embroi- 
dery :  it  is  not  at  all  known  when  the  flat- 
ted" metal  wire  began  to  be  spun  round 
linen  or  silk  thread.  The  spinning-mill, 
by  which  the  labour  is  now  performed,  is 
a  con  trivance  of  great  ingenuity. 

The  wire  first  spun  about  thread  was 
round ;  and  the  invention  of  previously 
making  the  wire  flat  is  probably  a  new 
epoch  in  the  history  of  the  art  :  and  it  is 
a  curious  fact,  that  three  times  as  much 
silk  can  be  covered  by  flatted  as  by  round 
wire ;  so  that  various  ornamental  articles 
are  cheap  in  the  same  proportion.  Besides, 
the  brightness  of  the  metal  is  heightened 
in  an  uncommon  degree,  and  the  article 
becomes  much  more  beautiful. 

The  greatest  improvement  ever  made  in 
this  art,  was  undoubtedly  the  invention  of 
tiie  large  drawing-machine,  which  is  dri- 
ven by  water,  or  by  steam,  and  in  which 
the  axle-tree,  by  means  of  a  lever,  moves 
a  pair  of  pincers,  that  open  as  they  fall 
against  the  drawing-plate  ;  lay  hold  of  the 
wire,  which  is  guided  through  a  hole  of 
the  plate  ;  shut  as  they  are  drawn  back  ; 
and  in  that  manner  pull  the  wire  along 
with  them. 

The  following  extract  from  the  memoir 
of  Messrs.  Mouchel,  of  l'Aigie,  in  the 
department  de  l'Orne,  on  the  manufac- 
ture of  iron  and  steel  wire,  may  be  in- 
teresting. 

This  is  one  of  the  most  considerable  ma- 
nufactories of  this  kind  in  France,  and  is 
said  to  produce  a  hundred  thousand  quin- 
tals of  iron  wire  annually,  in  cards  for 
wool-combing  only. 

When  the  iron  has  been  formed  into 
an  irregular  bar  of  about  a  centimetre 
(.39371  inches  English)  in  diameter,  they 
begin  to  draw  it  into  wire.  For  this  pur- 
pose they  first  pass  it  four  times  through 
the  drawing  plate.  The  fibres  which  ap- 
pear at  the  utmost  extension  of  the  mole- 
cules that  are  arranged  lengthways,  are 


removed  by  heat,  and  the  process  again 
repeated  three  times.  The  whole  opera- 
tion is  thus  repeated  five  times,  and  con- 
sequently the  wire  is  passed  through  fif- 
teen numbers ;  after  which  a  single  heat- 
ing is  sufficient  to  fit  it  to  pass  through  six 
others,  and  then  it  is  reduced  to  the  thick- 
ness of  a  knitting  needle.  Steel  wire  be- 
ing much  harder  than  that  made  of  iron, 
requires  to  be  passed  through  forty-four 
numbers,  and  to  be  annealed  even'  second 
time.  The  wire  is  drawn  with  either  the 
pincers  or  the  bobbin,  which  is  a  cylinder 
adapted  to  axle-trees.  This  last  was  in- 
vented by  the  grandfather  of  Messrs. 
Mouchel,  and  is  used  to  prevent  the 
marks  occasioned  by  the  application  of  the 
pincers.  The  degree  of  heat  required  in 
annealing  the  wire  must  be  regulated  by 
the  diameter ;  as  upon  this  much  of  the 
perfection  of  the  manufacture  depends. 
When  the  wire  is  sufficiently  stretched  at 
each  heating,  it  assumes  a  peculiar  colour, 
which  the  workmen  are  careful  to  ob- 
serve. 

For  annealing  the  wire,  fliese  manufac- 
turers employ  a  large  elevated  furnace,  in 
which  the  wire  is  supported  in  the  middle 
of  the  flames  on  bars  of  cast  iron.  This 
furnace  is  capable  of  containing  seven 
thousand  pounds  weight  of  wire,  so  ar- 
ranged, that  the  thickest  is  exposed  to 
the  greatest  heat ;  so  that  the  whole  be- 
comes equally  heated  in  the  same  time. 
An  inconvenience,  however,  is  experien- 
ced with  this  furnace,  which  leaves  the 
heated  wire  exposed  to  the  atmospheric 
air,  which  occasions  both  a  considerable 
loss  of  oxyd,  and  an  expense  in  removing 
it.  In  order  to  prevent  this,  they  have  in- 
vented another  furnace,  which  is  round, 
and  about  one  metre  six  decimetres  (near 
5  feet  3  inches  English)  in  diameter  ;  and 
one  metre  eight  decimetres  (5  feet  10  867S 
inches)  in  height,  exclusive  of  its  paiT.bo- 
lte  arch  and  chimney.  The  interior  of  this 
furnace  is  divided  into  three  parts  ;  the 
first  receives  the  cinders  ;  the  second  is 
the  fire  place  ;  and  the  third  receives  the 
wire,  which  is  placed  between  two  cylin- 
ders, situated  within  each  other,  and  made 
air  tight.  The  diameter  of  the  larger 
cylinder  is  about  one  metre  four  centime- 
tres (near  55  inches)  and  that  of  the  in- 
ner one  about  one  metre  (39  371  inches;) 
and  the  fire  circulates  about  the  exterior 
surface  of  the  former,  and  within  the  lat- 
ter. Several  pairs  of  cylinders  are  provi- 
ded, in  order  that  they  may  be  changed 
every  hour,  which  is  effected  by  means  of 
a  lever,  that  enables  one  man  to  draw  them 
out  or  push  them  in  at  pleasure.  These 
cylinders  are  not  opened  till  some  time 
after  they  are  drawn  out  of  the  fire,  which 


MAN 


MAN 


prevents  the  oxidation  that  would  take 
place  if  the  atmospheric  air  was  admitted 
while  the  wire  was  hot.  This  new  furnace 
is  more  expensive  than  that  which  was 
previously  used  ;  but  its  advantages  more 
than  counterbalance  this  expense-  It  is 
used  for  all  wire  intended  for  cards  ;  and 
the  large  furnace  for  that  of  a  larger  and 
harder  kind  ;  but  in  order  to  diminish  the 
formation  of  the  oxyd,  the  bundles  of  wire 
are  dipped  into  a  quantity  of  wet  clay,  and 
then  put  into  the  furnace,  and  suffered  to 
dry  before  the  fire  is  lighted. 

These  authors  make  use  of  two  sorts  of 
drawing  plates  ;  large  and  small ;  in  the 
formation  of  which  great  care  is  necessary, 
as  much  depends  upon  the  ability  with 
which  this  is  executed.  The  method  they 
employ  for  this  purpose  is  to  put  pieces 
of  iron  of  a  proper  size  and  quality,  into 
a  furnace  with  cast  steel,  and  increase 
the  heat  until  the  latter  is  fused ;  then 
the  iron  is  taken  out,  and  the  steel  that 
adheres  to  it  is  amalgamated  with  it  by 
gentle  blows. 

It  is  then  permitted  to  cool,  and  the 
same  process  repeated  several  times,  till 
the  plate  has  acquired  its  proper  form  and 
hardness.  It  is  necessary  that  these  plales 
should  be  of  considerable  thickness;  and 
the  smallest  used  by  Messrs.  Mouchel 
are  at  least  two  centimetres  (.78742  in- 
ches) in  thickness.  After  the  wire  has 
undergone  the  last  operation  in  the  work- 
shop of  the  wire  drawer,  and  is  reduced 
to  the  required  degree  of  fineness,  the 
smallest  of  which  is*stated  at  100,010  me- 
tres in  length  to  a  chiliogram  ;  or  109,366-| 
yards  to  21b.  Soz.  5dr.  avoirdupois,  by 
means  of  the  bobbin,  it  is  subjected  to 
the  process  of  dressage  or  straightening, 
which  is  esteemed  the  most  difficult  and 
delicate  of  all  the  operations.  By  this  it 
loses  the  bend  or  curve  it  had  acquired  on 
the  bobbins.  For  the  more  readily  and 
effectually  performing  this  part  of  the  m» 
nufacture,  these  authors  have  also  invent- 
ed apparatus  for  both  straightening  the 
wire,  and  determining  its  suppleness. 
But  for  a  particular  description  of  these, 
with  other  particulars,  and  a  table  of  the 
prices  of  the  different  sorts  and  sizes  of 
wire,  we  must  refer  to  the  Numbers  of 
the  Repertory  of  Arts. 

Those  persons  who  are  either  en- 
gaged or  interested  in  manufactures  of 
this  nature,  we  conceive  would  be  amply 
repaid  for  their  trouble  of  perusing  this 
memoir.  It  will  be  found  to  combine,  a 
much  greater  degree  of  scientific  ingenui- 
ty and  practical  experience  than  are  usu- 
ally met  with  in  similar  essays,  and  the 
success  with  which  these  have  been  ex- 


erted may  easily  be  inferred  from  the  fine- 
ness of  the  wire  produced.  From  the 
above  statement  it  appears  that  a  pound 
avoirdupois  of  the  smallest  wire  contains 
about  49,553  yards  in  length.  Now,  ad- 
mitting the  specific  gravity  of  this  wire  to 

2504 

be  7788,  and  a  pound  will  contain  -g^j 

2304  1 
cubic  inches.  Therefore  — 7—  X  ■  nw_g 
649  49553X36 

=  32159897  — 00000199316  inches  for 
the  area  of  its  section,  and  consequently, 
.0091593  for  its  diameter. 

Another  circumstance  which  confirms 
our  opinion  relative  to  the  formation  of 
the  drawing  plates,  is,  that  one  of  these 
large  plates  reduces  1400  chiliograms, 
from  the  largest  size  to  that  of  No.  6, 
which  is  about  the  thickness  of  a  knitting 
needle  ;  and  400  chiliograms  are  also  re- 
duced from  this  size  to  the  smallest  card- 
ing wire,  by  being  passed  twelve  times 
successively  through  a  single  small  plate. 
This  we  apprehend  could  not  take  place, 
unless  they  were  very  perfect. 

MANURE.    See  Agriculture. 

MANUSCRIPT,  copying  of— This  pro- 
cess, communicated  to  the  Philosophic 
Society  at  Paris  by  Charles  Caq_ue- 
best,  is  the  more  interesting  as  it  re- 
quires neither  machine  nor  preparation, 
and  may  be  used  in  any  situation.  It  con- 
sists in  putting  a  little  sugar  in  common 
writing  ink,  and  with  this  the  writing  is 
made  on  common  paper  sized  as  usual. 
When  a  copy  is  required,  unsized  paper 
is  taken  and  lightly  moistened  with  a 
sponge.  The  wet  paper  is  then  applied 
to  the  writing,  and  a  flat  iron,  such  as 
is  used  by  a  laundress,  of  a  moderate  heat, 
being  lightly  passed  over  the  unsized  pa- 
per, the  counter  proof  or  copy  is  imme- 
diately produced.  That  sugar  prevents 
ink  from  speedily  drying  lias  long  been 
known,  and  this  method  of  impression 
has  been  used  in  many  public  offices  at  an 
immense  saving  of  trouble  and  labour. 

MANUSCRIPTS,  to  revive  old,  when 
defaced. — Let  the  obliterated  paper  be 
slightly  moistened  with  a  sponge  dipt  in 
cold  water,  after  which  some  galls  finely 
levigated,  are  to  be  sifted  over  the  paper. 
When  it  is  perfectly  dry,  the  powder 
should  be  gently  shaken  off,  or  removed 
with  a  soft  brush  :  thus,  part  of  it  will 
adhere  to  the  former  outlines  that  still  ex- 
ist in  the  paper,  and  the  letters  will  im- 
mediately re-appear. 

MAPLE  SUGAli.— Under  this  article 
we  shall  consider  the  mode  of  manufac- 
turing sugar  from  the  maple  tree  (acer- 


MAP 


MAP 


taccharum  of  L.)  as  practised  in  different 
parts  of  the  United  States,  especially  in 
the  western  counties  of  all  the  middle 
states.  The  directions  given  in  this  article 
lor  manufacturing  maple  sugar  are  ex- 
tracted  from  a  pamphlet  published  in  this 
city  in  1790  Dr.  Uush,  in  the  third  vo- 
lume of  the  Amer  Phil.  Trans,  has  given 
an  excellent  paper  on  the  sugar  maple 
tree.  The  importance  of  this  tree  to  the 
United  States,  is  daily  exemplified  from 
the  immense  quantity  of  sugar  now  made. 
It  is  said  that  tour  men  will  turn  out  in 
from  four  to  six  weeks,  40  cwt.  of  good 
sugar.  The  following  calculation  of  uten- 
sils is  made  for  four  men. 

De:ail  and  description  of  the  necessary  uten- 
sils and  materials. 

Kettles. — Sixteen,  of  about  fifteen  gal- 
lons each. 

Iron  Ladles. — Two,  the  bowls  to  con- 
tain three  or  four  quarts  each,  for  shifting 
the  syrup  :  the  handles  to  have  sockets, 
which  may  be  extended  with  wood  to  any 
convenient  length. 

Trammels  or  Pot-Racks. — Sixteen,  one 
for  each  kettle,  the  flat  part,  eighteen  in- 
ches long ;  and  the  round  or  lower  piece, 
the  same ;  so  as  to  lengthen  to  about  three 
feet,  occasionally. 

Screw  Jugers.— Four,  of  an  half,  three 
quarters,  and  one  inch,  for  boring  the 
trees.  Chopping  notches  into  the  tree 
from  year  to  year,  should  be  forborne ; 
an  auger  hole  answers  the  purpose  of 
drawing  off  the  sap,  equally  well,  and  is 
no  injury  to  the  tree. 

Buckets. — Eight  or  ten,  of  three  gallons 
each,  at  least,  for  collecting  the  sap. 

Boards. — Eight  or  ten,  round  pieces,  to 
lay  on  the  surface  of  the  sap,  at  the  top  of 
;he  buckets,  to  prevent  its  splashing  over. 

Coolers. — Three  or  four  tubs,  of  about 
fifteen  gallons  each  (kettles  will  answer 
the  purpose,  to  receive  the  syrup  from  the 
boilers,  when,  upon  trial  from  the  proof 
stick,  it  draws  into  a  thread  between  the 
thumb  and  finger,  as  hereafter  described. 

Yokes. — Four,  to  go  across  the  shoul- 
ders of  the  persons  employed  in  collect- 
ing the  sap,  having  a  bucket  suspended  at 
each  end. 

Troughs. — Eight  hundred  should  be 
made  of  white  pine,  white  ash,  water 
ash,  aspen,  linden  or  bass-wood,  poplar, 
common-maple  or  sugar-maple  :  avoid  for 
this  use,  the  butter-nut,  \juglans  alba  (oh- 
longa>y\  chesnut  and  oak ;  these  would 
either  discolour  the  sap,  or  give  it  an  im- 
proper taste.  A  person  acquainted  with 
this  business,  can  cut  down  the  timber 
proper  for  the  purpose,  and  hollow  out 
VOL.  II. 


about  twenty  of  these  troughs  in  a  day ; 
they  generally  hold  from  two  to  three  gal- 
lons :  the  largest  should  be  placed  to  re- 
ceive the  sap  of  those  trees  that  are  most 
thriving,  and  which  yield  the  greatest 
quantity.  It  may  also  be  noted,  that  white- 
ash  and  white-pine  will  make  the  troughs 
when  green  ;  the  other  kinds  of  timber, 
above-mentioned,  should  be  seasoned,  or 
they  will  be  liable  to  leak. 

Store  Troughs. — Where  large  cisterns, 
fit  for  the  purpose,  cannot  be  had,  which 
will  generally  be  the  case  in  a  new  coun- 
try, troughs  may  be  made  of  the  white- 
pine,  by  felling  a  large  tree  of  that  kind, 
and  fixing  it  in  a  level  position  ;  the  upper 
side  to  be  dug  out  in  the  shape  of  a  man- 
ger for  feeding  cattle :  the  larger  it  can 
be  made  for  receiving  the  green  sap,  the 
better.  White-ash  and  linden  or  brass- 
wood,  will  also  answer  the  purpose  ; 
should  any  of  them  split  and  leak,  they 
may  be  caulked  tight.  These  troughs 
should  be  at  a  convenient  distance  from 
the  boilers,  in  a  cool  place,  and  under 
cover,  to  prevent  snow,  rain,  &c.  mixing 
with  the  sap.  A  linen  strainer  should  be 
so  fixed  that  the  sap,  when  collected  in 
buckets,  may  pass  through  such  strainer 
into  these  troughs,  at  one  end;  and,  at 
the  other  end,  room  should  be  left  to  dip 
out  for  feeding  the  boilers. 

Sheds,  Wells,  &c. — The  exposed  man- 
ner  in  which  sugar  has  been  usually 
made,  in  the  back  country,  is  attended 
with  many  inconveniences,  especially  in 
windy  weather,  when  the  ashes,  leaves, 
&c.  may  be  blown  into  the  boilers,  and 
thereby  discolour  the  syrup,  or  injure  its 
flavour ;  neither  can  the  keeping  up  a 
proper  degree  of  heat  be  always  effected 
in  an  exposed  situation  To  remedy  these 
inconveniences  it  is  recommended  that  a 
back  wall,  for  the  fire-place,  be  erected, 
eighteen  or  twenty  inches  high,  and  to  ex- 
tend a  sufficient  length  for  all  the  boilers 
employed.  This  wall  may  be  made  of 
stones  laid  in  clay  or  loam,  where  lime- 
mortar  is  not  readily  to  be  had.  For  sav- 
ing the  ashes,  and  the  greater  convenience 
in  making-  and  continuing  a  vegular  firc„ 
under  the  boilers,  a  hearth  of  flat  stone, 
about  three  feet  wide,  should  be  made,  to 
extend  an  equal  length  with  the  back  wall. 
And  further  to  obviate  the  bad  effects, 
which  too  open  an  exposure  is  subject  to,^ 
it  being  observed  where  a  number  of 
boilers  are  placed  in  a  range,  those  at, 
and  near,  the  outer  ends,  do  not  succeed 
so  well  as  the  more  central  ones,  it  is 
strongly  recommended  that  sheds  be 
erected,  to  extend  over  and  cover  the 
whole  length  of  the  hearth  ;  and  so  form, 
edthat  the  smoke  may  pass  off,  and  be  al 
G 


MAP 


MAP 


the  same  time  a  shelter  from  high  winds, 
rain,  snow,  &c.  For  graining  the  syrup, 
after  it  is  brought  to  a  proper  state  in  the 
boilers,  it  will  be  right  to  have  a  separate 
shed  or  building,  v\  which  two  of  the  six- 
teen kettles  should  be  fixed ;  for  this  ser- 
vice, charcoal  is  much  better  than  wood, 
as  the  heat  or  flame  should  be  confined  to 
the  bottoms  of  the  kettles  ;  and  be  uni- 
form and  regular,  to  guard  against  burn- 
ing or  scorching.  A  wall,  as  above  de- 
scribed, should  be  made  at  the  back  of 
the  fire-place,  as  well  as  at  each  end; 
and  the  hearth  or  bottom  laid  with  fiat 
stones,  on  which  charcoal  is  to  be  placed. 

Jlndirons. — Pieces  of  cast-iron,  some- 
thing like  andirons,  and  to  serve  the  same 
purpose,  will  be  very  useful :  they  should, 
in  the  long  part,  be  two  feet  and  an  half, 
and  two  inches  square  ;  the  turn  at  the  in- 
ner end,  four  inches  downwards,  and  a 
small  turn  upwards,  at  the  outer  end,  of 
about  two  inches,  to  prevent  the  wood 
from  rolling  Of  these,  there  should  be 
a  number  to  suit  the  extent  of  the  fire- 
place, to  be  placed  at  the  distance  of  five 
or  six  feet  from  each  other. 

Sugar-Moulds. — These  should  be  made 
of  seasoned  boards,  or  of  such  wood  as 
will  not  impart  a  taste  to  the  sugar,  and 
somewhat  resembling  a  mill-lumper,  about 
twenty-seven  inches  long,  and  ten  or  twelve 
inches  wide,  at  the  top,  and  tapered  to  the 
Width  of  one  inch,  at  the  lower  end. 

Frames,  to  place  the  moulds  in,  above 
described,  should  be  formed  so  as  to  ad- 
mit the  moulds  to  rest  in  them,  about  half 
their  depth. 

Gutters,  spouts,  or  narrow  troughs, 
should  be  fixed  within  the  frames,  under 
the  moulds,  in  a  descending  position  ; 
the  lower  ends  to  enter  covered  casks  or 
vessels,  so  that  when  the  plugs  or  stop- 
pers are  drawn  from  the  bottom  of  the 
moulds,  which  may  be  done,  in  about 
twenty-four  hours  after  they  are  set,  the 
molasses  that  will  run  therefrom,  may  fall 
into  these  gutters,  and  pass  readily  into 
the  covered  vessels,  which,  if  open,  would 
be  exposed  to  dust  and  dirt. 

Prickers.— So  termed  by  the  sugar-ba- 
kers, about  twelve  inches  long  and  a  half 
an  inch  diameter,  at  one  end,  and  the 
other,  brought  to  a  point  ;  for  want  of 
iron,  they  maybe  made  of  hardwood;  a 
few  hours  after  the  moulds  are  unstopped, 
the  prickers  should  be  run  up  to  the  bot- 
tom of  them,  three  or  four  inches,  to 
make  way  for  the  whole  quantity  of  mo- 
i  asses  to  pass  off. 

Process  or  mode  of  manufacturing  the  sap 
of  maple,  -vhich  by  further  experience 
and  close  observation  may,  probably, 


hereafter,  admit  of  considerable  improve- 
ment. 

Seasons  for  Tapping. — By  trials,  made 
in  the  month  of  February,  it  will  readily 
be  discovered,  when  this  valuable  tree 
ought  to  be  bored,  for  the  purpose  of  ex- 
tracting the  sap,  as  in  that  month,  either 
earlier  or  later,  according  to  the  season, 
it  generally  begins  to  yield  a  sufficient 
quantity  for  commencing  the  business. 

Tapping  or  Boring. — Four  hundred 
trees,  each  bored  with  two  holes,  as  near- 
ly as  may  be  on  the  south  side  ;  and  also 
with  two  holes  on  the  north  side  of  the 
tree,  in  the  early  part  of  the  season,  with 
screw  augers  from  two  to  four  quarters  of 
an  inch,  according  to  the  size  of  the  tree  ; 
and  toward  the  middle  of  the  season,  a 
like  number  of  trees  to  be  bored  in  the 
same  manner,  is  recommended,  as  a  bet- 
ter mode  for  the  management  of  four 
hands,  than  if  the  whole  number  of  eight 
hundred  trees  were  tapped  at  the  first 
running  of  the  sap.  The  sap  of  the  second 
parcel  tapped,  will  be  found  richer,  and 
more  productive,  than  if  a  part  had  been 
extracted  earlier.  The  auger  should  en- 
ter the  tree,  at  first,  not  more  than  three 
quarters  of  an  inch  :  the  holes  may,  at 
several  times,  be  deepened  to  the  extent 
of  two  inches  and  an  half,  as  the  manner 
of  the  sap's  running  may  render  necessa- 
ry. The  hole  should  be  made  slanting 
or  descending,  so  that  the  sap  may  run 
freely  in  frosty  weather,  and  not,  by  a 
slow"  motion,  be  liable  to  freeze  in  the 
mouth  of  the  orifice.  In  these  holes, 
spouts  should  be  fixed,  to  project  from 
the  tree,  from  eight  to  twelve  inches,  and 
not  to  enter  the  tree  more  than  about  half 
an  inch ;  as  the  farther  they  enter,  the 
more  the  running  of  the  sap  is  obstruct- 
ed :  they  should  be  prepared,  in  readiness 
for  the  season,  of  elder  or  sumach. 

Preserving  the  Sap.— In  the  early  part 
of  the  season,  the  sap  will  keep  two  or 
three  days  without  injury;  but  as  the 
spring  advances,  it  will  be  necessary  to 
boil  the  sap  the  day  after  it  is  collected, 
or  it  may  ferment  and  sour. 

Lime  '—  To  every  half  barrel,  or  fifteen 
gallon  kettle,  a  table  spoonful  of  slacked 
lime  should  be  put  in  while  the  sap  is 
warming,  and  before  it  boils  ;  this  pro- 
motes the  rising  of  the  scum  and  forming 
of  the  grain. 

Boiling  —  A.  smart  fire  should  be  kept 
up  while  the  sap  is  boiling.  As  the  scum 
rises  be  careful  to  skim  it  off.  When  the 
liquor  is  reduced  one  half  in  quantity, 
lade  the  second  kettle  from  the  end,  into 
the  end  one  \  and  when  the  contents  ot 
three  or  four  kettles  can  be  contained,  in 


MAP 


MAP 


one,  let  the  whole  be  laded  into  that,  at 
the  end  ;  filling-  up  the  empty  kettles, 
without  delay,  with  fresh  sap.  As  the 
liquor  in  the  end  kettle,  removed  from 
those  which  have  been  mentioned,  be- 
comes a  syrup,  it  should  be  strained 
through  a  good  blanket  or  woollen  cloth  ; 
and  care  must  be  taken  not  to  suffer  it  to 
boil  so  long1  as  to  be  too  thick  to  be  strain- 
ed in  this  manner.  It  should,  when  thus 
cleansed  from  its  impurities,  stand  in 
buckets  or  other  suitable  vessels  twelve 
hours  or  more,  that  the  particles  of  lime 
and  other  remaining  sediment  may  settle 
to  the  bottom  ;  after  which,  it  should  be 
so  gently  poured  off  into  a  kettle  or  boil- 
er, as  not  to  carry  with  it  any  of  these  set- 
tlings. However,  they  need  not  be  wholly 
lost ;  they  will  mostly  contain  a  conside- 
rable quantity  of  sugar  or  syrup :  by 
pouring  fresh  sap  on  them,  stirring  them 
well  together,  and  suffering  them  to  stand 
a  while  to  settle ;  a  great  part  of  the  va- 
luable sweets  contained  in  such  sediment 
may  be  saved.  It  may  be  further  noted, 
that  when  the  sap  is  weak,  which  is  gene- 
rally the  case  towards  the  latter  part  of 
the  season,  it  requires  more  boiling  and  a 
higher  proof  than  that  collected  earlier 
and  of  greater  strength. 

N.  B.  The  method  above  described  was 
(actually)  pursued  in  the  last  year,  and 
appeared  to  answer  well ;  it  is  neverthe- 
less believed,  by  a  judicious  sugar-boiler, 
that  it  would  be  best  to  avoid  letting  the 
syrup  stand  twelve  hours  after  being 
strained  through  a  blanket :  when  the  pro- 
cess is  begun,  the  sooner  it  is  completed, 
in  his  opinion,  the  better  :  the  design  of 
its  so  standing  for  twelve  hours,  being 
chiefly  intended  to  give  sufficient  time  for 
the  particles  of  lime  and  other  sediment 
to  collect  at  the  bottom  of  the  kettle.  It  is 
proposed  that  lime  should  be  mixed  with 
a  quantity  of  fresh  sap  in  the  evening, 
and  be  well  stirred  ;  the  large  particles  of 
lime  in  this  case,  will  be  likely  to  subside 
before  morning,  and  the  clear  sap  so  im- 
pregnated may  be  mixed,  the  next  morn- 
ing, in  proper  proportions,  in  the  several 
kettles  ;  observing,  however,  that  in  this 
mode  more  lime  will  be  necessary,  as 
less  of  its  strength  will  be  extracted  by 
cold  than  by  hot  water. 

Graining. — The  syrup  having  stood 
twelve  hours  or  upwards,  is  then  to  be 
gently  poured  into  a  kettle  or  boiler,  as 
above-mentioned ;  which  would  be  best 
placed  over  a  fire  made  of  charcoal  as  be- 
fore hinted  ;  unless  the  kettle  is  so  fixed 
in  a  furnace  or  in  such  a  situation,  that  the 
flame  can  be  confined  to  the  bottom ;  for 
if  it  be  suffered  to  pass  on  the  sides,  it 
endangers  the  syrup's  being  burned.  This 


operation  should  also  be  performed  with 
a  smart  fire,  to  be  uniformly  and  equally 
kept  up,  in  which,  as  well  as  in  boiling 
the  green  sap,  the  use  of  butter,  hog's- 
lard,  and  other  fat,  is  not  only  very  use- 
ful and  advantageous,  but  absolutely  ne- 
cessary. When,  in  the  course  of  boiling, 
the  sap  rises  towards  the  top,  a  piece  of 
fat  equal  in  size  to  a  small  nutmeg,  thrown 
in,  will  keep  it  down.  Particular  care 
should  be  taken  to  prevent,  by  these 
means,  the  rising  of  the  syrup  when 
graining,  which  may  require  a  larger  pro- 
portion of  butter,  &c.  It  is  found  that 
the  evaporation  is  much  more  expeditious, 
and  it  is  believed  that  the  quantity  of  su- 
gar made  is  larger,  when  a  careful  guard 
is  kept  up  to  prevent  the  sap,  and  parti- 
cularly the  syrup,  when  graining,  from 
rising  ;  by  the  timely  introduction  of  a 
piece  of  fat  as  above  described.  To  form 
a  judgment  when  the  syrup  is  sufficiently 
boiled,  take  out  with  quickness  the  stir- 
ring-stick, which  is  constantly  kept  in  the 
boiler  for  the  purpose  of  taking  the  proof, 
rub  some  of  the  syrup  off  the  lower  end  of 
it  with  the  thumb,  and  if,  on  applying  the 
finger  thereto  it  draws  into  a  thread,  it 
may  be  deemed  in  a  proper  state  to  be  la- 
ded into  a  tub  or  cooler.  Then  it  should 
be  forthwith  stirred,  and  that  incessantly, 
with  a  stirring-stick  about  three  inches 
broad,  until  the  grain  can  be  felt  between 
the  finger  and  thumb,  when  it  is  in  a  fit 
state  to  be  poured  into  the  moulds.  The 
managing  of  sugar -works  in  the  West-In- 
dies, and  in  the  refining  houses  in  North- 
America,  has  been  found  to  require  much 
judgment  and  experience  to  conduct  the 
business  to  the  best  advantage ;  indeed, 
it  seems  hardly  possible,  to  communicate 
to  persons  who  have  little  knowledge  of 
the  matter,  and  in  terms  clearly  to  be  un- 
derstood, full  information  as  to  the  differ- 
ent appearances  of  the  syrup  in  the  time 
of  boiling,  and  to  point  out  the  moment 
when  some  material  movements  or  chan- 
ges ought  to  be  made  ;  nevertheless, from 
the  foregoing  hints  and  directions,  which 
are  grounded  on  observation  and  expe- 
rience, it  is  hoped  much  may  be  derived  ^ 
and  that  from  year  to  year,  greater  advan- 
ces and  improvements  may  be  made  in 
this  valuable  business. 

Claying  or  Whitening  the  Sugar. — To 
promote  the  molasses  passing  more  freely 
from  the  sugar,  when  draining  in  the 
moulds,  and  to  improve  its  colour  in  two 
or  three  days  after  the  moulds  are  un- 
stopped at  the  lower  end,  mix  white  clay 
with  water  so  as  to  reduce  it  to  a  thin 
mortar  ;  with  this  cover  the  top  of  the 
moulds  one  inch  and  a  half  thick ;  when 
this  covering  appears  dry,  remove  it,  ^nd 


MAP 


supply  the  place  with  a  fresh  covering  of 
about  two  inches  thick. 

Although  it  is  apprehended  that  the  use 
of  clay  as  above  set  forth,  particularly  in  the 
latter  part  of  the  season,  will  be  found  be- 
neficial, it  may  however  be  prudent  to 
continue  or  decline  the  practice,  accord- 
ing to  the  effect  or  use  it  appears  to  be  of 
on  a  careful  trial  s  the  quantity  of  clay 
must  be  proportioned  to  the  manner  in 
which  the  sugar  has  been  boiled  ;  if  high 
boiled  it  will  require  much  more  clay  than 
if  boiled  low.  It  is  also  thought  the  use 
of  clay  lessens  the  quantity  of  sugar,  per- 
haps one  fifth  part,  and  may  be  more  or 
less,  according  to  the  know  ledge  of  the 
person  who  undertakes  the  business.  It 
may  be  further  remarked,  that  if  the  quan- 
tity of  sugar  be  lessened  in  weight  by  clay- 
ing, one  fifth  part,  it  is  not  to  be  concluded 
that  the  whole  of  this  fifth  part  will  be 
eventually  lost ;  there  will  be  more  syrup 
than  there  otherwise  would  have  been, 
independent  of  the  water  from  the  clay 
that  passes  through  the  sugar. 

Molasses  and  Vinegar.  -When  the  trees 
of  the  second  tapping  become  poor  in 
quantity  and  quality,  which  may  be  about 
the  tenth  of  April,  or  perhaps  sooner, 
then  the  number  of  fresh  tapped  trees  will 
yield  a  sap,  of  which  may  be  made  good 
molasses,  and  also  excellent  vinegar. 

In  all  sugar  plantations  it  will  be  advan- 
tageous to  cut  out  the  different  sorts  of* 
timber  which  grow  intermixed  with  the 
sugar-maple,  and  even  those  of  that  spe- 
cies which  are  not  thriving,  promising 
trees.  The  timber  so  cut  out  will  serve 
for  fuel  for  the  boilers,  and  leave  greater 
openings  for  the  rays  of  the  sun  to  enter, 
which  will  have  a  tendency  to  improve 
and  enrich  the  remaining  trees.  The 
ground  so  cleared  of  all  except  the  maple- 
tree,  it  has  been  observed,  is  particularly 
favourable  for  pasture  and  the  growth  of 
grass.  "  Whether  this  tree  is  injured  or 
impoverished  by  repeated  tappings,"  is 
an  enquiry  to  be  expected,  and  has  been 
frequently  made  of  late,  by  persons  who 
have  anxiously  wished  for  the  success  of 
this  business.  It  has  been  before  observed, 
that  it  will  bear  much  hardship  and  abuse, 
and  it  may  be  added,  that  there  are  in- 
stances, particularly  among  the  old  set- 
tlements on  the  North  River,  of  trees 
which  have  been  tapped  for  fifty  years  or 
upwards,  and  continue  to  yield  their  sap 
in  the  season,  equal  to  any  brought  into 
use  of  later  time ;  indeed,  it  is  asserted 
with  confidence,  by  persons  who  have 
had  some  years  experience,  that  these 
trees  by  use,  be'eome  more  valuable,  yield- 
ing a  sap  of  a  richer  quality.  See  Sugar. 


MARBLES  are  either  antique  or  mo- 
dern. The  following  are  of  the  former  -. 
Parian,  Pentellic,  Greek  white,  transiucid 
white,  flexible  white,  w  hite  marble  of  Lu- 
ni,  white  marble  of  Carrara,  white  marble 
of  mount  Uymettus,  black  antique,  red 
antique,  green  antique,  red  spotted, 
leek,  &c.  Of  the  latter,  we  have  treated 
under  the  article  Limestone. 

MARBLE,  Colouring  of.  Heat  is  some- 
times necessary  in  communicating  the  co- 
lour. In  order  to  fix  the  colouring  matter 
into  the  substance  of  marble,  a  lixivium  of 
quick  lime,  urine,  dung,  &.c.  with  potash, 
may  be  used ;  common  ley  is  also  used ; 
for  some  colours,  spirit  of  wine  is  useful, 
and  for  others,  oily  liquors,  or  common 
white  wine.  For  blue  colour,  litmus  held 
'in  solution  may  be  applied.  Dragon's 
blood,  cochineal,  and  alkanet  root  may  be 
severally  used.  If  marble  be  heated,  and 
the  following  substances  rubbed  on,  the 
several  colours  will  be  formed,  viz.  dra- 
gon's blood  for  red  ;  gamboge  for  a  yel- 
low ;  green  wax  for  a  green  ;  common 
brimstone,  pitch,  and  turpentine,  for  a 
brown  colour. 

A  fine  colour  is  given  by  the  fol- 
lowing :  Take  sal  ammoniac,  vitriol,  and 
verdigrise,  of  each  equal  quantities.  Va- 
rious other  processes  may  be  used  for 
staining  marble,  which  will  be  noticed 
hereafter. 

In  1778,  a  patent  was  granted  to  Mr. 
Ritchie,  for  his  invention  of  an  art  or  me- 
thod of  inlaying  scaglio'a,  or  plaster,  in 
marble  or  metais,  so  as  to  imitate  flowers, 
fruits,  trees,  birds,  beasts,  landscapes, 
and  every  kind  of  ornament.  This  patent 
is  now  expired ;  but,  as  it  is  practicable 
only  by  statuaries  and  artists,  the  inquisi- 
tive reader  will  consult  the  10th  volume 
of  the  Repertory  of  Arts  and  Manufac- 
tures. 

MARBLE,  polishing  of,  is  performed 
by  first  rubbing  it  well  with  a  free  stone, 
or  sand,  till  the  strokes  of  the  saw  are 
worn  off,  then  with  pumice  stone,  and  af- 
terwards with  emery. 

MARBLING  of  books  or  paper,  is  per- 
formed thus,  which  is  different  from  the 
plan  before  mentioned  (article  Dyeing.) 
Dissolve  four  ounces  of  gum  arabic  in  2 
quarts  of  water  :  then  provide  several  co- 
lours mixed  with  water  in  pots,  and  with 
pencils  sprinkle  them  upon  the  gum  wa- 
ter, which  must  be  put  in  some  broad 
vessel :  then  with  a  stick  draw  them  out, 
so  as  to  produce  a  variety.  Having  done 
this,  hold  your  book  or  books,  close  to- 
gether, and  only  dip  the  edges  in,  on  the 
top  of  the  water  and  colours,  very  lightly, 
which  will  produce  the  effect. 


MAR 


MAU 


The  Domestic  Encyclopedia,  gives  the 
following  observations  on  this  subject : 

There  are  several  kinds  of  marbled  pa- 
per, which  vary  only  in  the  forms  or 
figures  of  colouring :  some  are  dotted ; 
others  drawn  in  irregular  lines ;  but  the 
method  of  tinging  them,  simply  consists 
in  dipping  the  paper  in  a  thick  solution  of 
gum  tragacanth,  over  which  the  colours 
are  uniformly  spread,  after  having  been 
ground  with  ox-gall,  and  spirit  of  wine. 

The  paper  must  first  be  immersed  in 
clear  water,  the  sheets  regularly  folded 
over  each  other,  and  covered  with  a 
weight.  It  is  now  to  be  carefully  laid  on 
the  colouring  solution,  and  pressed  softly 
with  the  hand,  that  it  may  bear  equally  on 
the  whole  Next,  it  must  be  suspended 
in  order  to  dry  ;  and,  as  soon  as  the  mois- 
ture is  evaporated,  the  paper  is  polished 
by  rubbing  it  with  a  little  soap,  and 
smoothing'  it  either  with  glass  highly  bur- 
nished, or  with  a  polished  agate. 

The  colours  usually  employed  for  red, 
are,  carmine,  lake,  or  vermillion — for  yel- 
low, Dutch-pink  and  yellow  ochre — for 
blue,  Prussian-blue  and  verditer — for 
green,  verdigrise,  a  mixture  of  Duich- 
pink,  and  Prussian-blue,  in  various  pro- 
portions— for  orange,  the  orange-lake,  or 
a  composition  of  vermillion,  or  red-lead, 
with  Dutch-pink — and  lastly,  for  purple, 
rose-pink  and  Prussian-blue. 

These  different  colours  are  first  to  be 
finely  triturated  with  spirit  of  wine,  when 
a  small  proportion  of  gall  is  to  be  added, 
and  the  grinding  of  the  whole  repeated. 
The  proper  quantity  of  gall  can  be  easily 
ascertained  by  comparative  trials  ;  because 
there  must  be  only  such  a  proportion  of  it 
used,  as  will  suffer  the  spots  of  the  vari- 
ous tinging  matters  to  unite,  when  sprink- 
led on  the  solution  of  tragacanth,  without 
intermixing,  or  running  into  each  other. 
The  whole  being  thus  prepared,  the  solu- 
tion is  to  be  poured  into  different  vessels, 
according  to  the  colours  employed,  which 
are  to  be  sprinkled  on  the  surface  ;  and 
the  process  of  marbling  is  completed  by 
laying  the  paper  on  the  mixture,  in  the 
•manner  above  directed. 

Marbling  on  wood  or  japanning,  accord- 
ing  to  Imison. — Take  of  the  best  transpa- 
rent yellow  amber,  what  quantity  you 
please  ;  beat  it  to  a  powder ;  put  it  into  a 
clean  crucible  that  is  glazed  within  ;  let 
it  melt  over  a  gentle  charcoal  fire;  and 
stir  it  well,  to  keep  it  from  burning  ;  then 
pour  it  upon  a  smooth  clean  marble  table, 
let  it  cool,  and  beat  it  again  to  powder. 
Take  afterwards  clean  turpentine,  and,  in 
a  glass,  warm  it  in  a  sand  heat ;  put  into 
it  the  beaten  amber ;  let  them  simmer, 
and'  dissolve  gently  together,  till  they  are 


of  a  consistence  fit  to  be  used  with  a  pen-- 
cil ;  strain  them  through  a  cloth,  and  you 
will  have  the  finest  varnish  possible ;  and 
although  it  be  of  a  brownish  colour,  yet, 
when  laid  on,  it  has  a  fine  clear  gloss. 

The  colours  wherewith  you  are  to  mar- 
ble, are  the  following ;  lamp-black,  brown- 
red,  ochre,  vermillion,  which  are  to  be 
ground  with  linseed  oil ;  and  white  lead, 
ground  with  oil  of  almonds. 

For  a  white ;  lay  your  first  ground  with.- 
linseed  oil,  and  if  there  are  any  holes  in 
the  wood,  fill  them  up  with  chalk  temper- 
ed with  size.  For  a  black  ground,  lay  it 
first  with  lamp-black  and  size  ;  when  the 
ground  is  dry,  mix  the  vermilion  with  the 
above  described  varnish,  and  with  a  hair 
pencil  lay  it  on  with  an  even  and  quick 
hand;  repeat  this  three  or  four  times  till 
it  is  bright  and  fine,  and  lay  the  varnish, 
by  itself,  over  it  twice,  or  thrice;  then 
mix  your  other  colours  with  the  varnish* 
in  an  oyster-shell,  or  in  little  cups ;  and 
with  them  marble  upon  the  ground  you 
have  prepared,  in  imitation  of  any  thing 
you  please. 

To  marble  upon  wood,  according  to  Imi- 
son.— Take  the  white  of  eggs,  and  beat 
them  up  until  you  can  write  or  draw  there- 
with ;  then  with  a  pencil,  or  feather,  draw 
what  veins  you  please  upon  the  wood ; 
after  it  it  dried  and  hardened  for  two 
hours,  take  quick-lime,  and  mix  it  well 
together  with  wine ;  and  with  a  brush,  or 
pencil,  paint  the  wood  all  over  :  after  it 
is  thoroughly  dry,  rub  it  with  a  scrub- 
bing-brush, so  that  both  the  lime  and  the 
whites  of  t  he  eggs  may  come  off  together  ; 
then  rub  it  with  a  linen  rag,  until  it  ia 
smooth  and  fine ;  after  which,  you  may 
lay  over  a  thin  varnish,  and  you  win  have 
a  fine  marble  wood.  Or, 

Grind  white-lead,  or  chalk  together, 
with  water,  upon  a  marble  very  fine;  then 
mix  it  up  with  the  whites  of  well-beaten 
eggs,  wherewith  paint,  or  marble,  as  you 
think  proper  ;  when  dry,  strike  it  over 
with  a  ley  made  of  lime  and  urine,  and 
this  will  give  the  wood  a  brown-red  co- 
lour :  upon  this  colour  you  may,  when 
dry,  marble  again  with  the  whites  of 
eggs  ;  and  again,  when  dry,  give  it  ano- 
ther brush  with  the  ley :  after  you  have, 
with  a  scrubbing-brush,  rubbed  off  the 
marbling  with  whites  of  eggs,  you  may 
strike  once  more  all  over  with  the  ley ; 
and  your  work,  when  dry  and  polished, 
will  look  very  agreeable,  and  of  a  fine 
marbling. 

To  imitate  marble  upon  ivory,  according 
to  Imison. — Melt  bees-wax  and  tallow  to- 
gether, or  else  yellow  and  white  bees- 
wax, and  lay  it  over  your  ivory ;  then 
with  an  ivory  bodkin,  open  the  strokes 


MAR 


MAS 


that  are  to  imitate  marble ;  pour  the  so- 
lution  of  some  metal  or  other  on  them, 
and  let  it  stand  a  little  while  ;  then  pour 
it  off",  and  when  it  is  dry,  cover  those 
strokes  again  with  wax,  and  open  some 
other  veins  with  your  bodkin  for  another 
metallic  solution  ;  and  this  repeat  to  the 
number  of  colours  you  design  to  give  it. 

N.  B.  The  solution  of  gold  gives  it  a 
purple ;  of  copper,  a  green  ;  of  silver,  a 
lead-black  ;  of  iron,  a  yellow  and  brown 
colour.  These  solutions  well  managed, 
and  applied  on  ivory,  will  entirely  answer 
the  design  of  the  artist. 

By  this  method  you  may  imitate  tor- 
toise shell,  and  several  other  things,  on 
ivory. 

To  imitate  marble,  according  to  Itnison. 
— Take  plaster  of  Paris,  quick-lime,  salt, 
ox-blood,  stones  of  different  colours,  also 
pieces  of  glass,  all  beat  to  powder,  and 
mixed  up  to  the  consistence  of  a  paste, 


with  vinegar,  beer,  or  sour  milk 

then  lay  it  into  tables,  pillars,  or  what  I  a  variety  of  veins ;  then,  with  another 


must  be  pretty  hot,  so  that  the  drops 
upon  the  stone  may  unite  and  incorporate 
together;  when  you  have  poured  your 
ground  even  all  over,  then,  if  you  will, 
put  a  thin  wainscot  board  upon  it  ;  this 
must  be  done  whilst  the  sulphur  is  hot, 
making  also  the  board  hot,  which  must 
be  thoroughly  dry,  in  order  to  cause  the 
sulphur  to  stick"  the  better  to  it;  and 
when  it  is  cold,  poiish  it  with  oil  and  a 
cloth,  and  it  will  look  very  beautiful. 

To  paint  on  -wood  in  imitation  of  marble, 
according  to  Imison.—F'ivst  lay  a  ground 
(repeating  it  seven  or  eight  times)  with 
white ;  then  marble  it  with  what  colours 
you  please,  after  you  have  tempered  them 
with  the  white  of  eggs  and  mixed  a  little 
saffron  water  therewith.  If  you  are  not 
used  to  marbling  with  a  pencil,  you  may 
pour  one  sort  of  colour,  here  and  there  a 
little,  upon  the  white  prepared  table,  then, 
holding  and  turning  it  shelving,  the  co- 
lour will  disperse  all  over  the  ground,  in 


you  will ;  let  it  stand  until  it  is  thorough 
fy  dry  ;  then  rub  it  with  a  pumice,  and 
polish  it  with  tripoii,  giving  it  the  finish- 
ing stroke  by  rubbing  it  over  with  leather 
and  oil.  Or, 

With  finely  pulverized  plaster  of  Paris, 
and  size  of  parchment,  make  a  paste; 
mix  with  it  as  many  colours  as  you  please; 
spread  it  with  a  trowel  over  a  board,  and 
when  dry  proceed  as  before. 

To  imitate  marble,  in  sulphur,  accord- 
ing to  Imison. — To  do  this,  you  must  pro- 
vide yourself  with  a  flat  and  smooth  piece 
of  marble,  on  which  make  a  border  or 
wall,  to  encompass  either  a  square  or  oval 
table,  which  you  may  do  either  with  wax 
or  clay.  When  this  is  done,  provide,  and 
have  in  readiness,  several  sorts  of  colours, 
each  separately  reduced  to  a  fine  pow- 
der ;  as  for  example  ;  white  lead,  vermi- 
lion, lake,  orpiment,  masticot,  smalt, 
Prussian  blue,  and  such  like  colours. 
After  you  are  provided  with  them,  melt, 
on  a  slow  fire,  in  several  glazed  pipkins, 
some  sulphur ;  put,  in  each,  one  particu- 
lar sort  of  colour,  and  stir  it  well  toge- 
ther ;  then,  having  before  oiled  the  mar- 
ble all  over  within  the  border,  drop  with 
one  colour,  quickly,  spots  upon  it,  of  lar- 
ger^ and  less  sizes;  then  take  another  co- 
lour, and  do  as  before ;  and  so  on,  till 
the  stone  is  covered  with  spots  of  all  the 
colours  you  design  to  use  :  then  you  must 
conclude  what  colour  the  mass  or  ground 
of  your  table  is  to  be  ;  if  you  would  have 
it  of  a  grey  colour,  then  take  fine  sifted 
ashes,  and  mix  it  up  with  melted  sulphur ; 
or  if  of  red,  with  red  ochre ;  if  white,  with 
white  lead ;  if  black,  with  lamp  black,  or 
ivory  black.  Your  sulphur  for  the  ground 


colour,  proceed  in  the  same  manner ;  and 
so,  with  as  many  as  you  think  proper: 
after  it  is  dry,  you  may,  with  a  pencil, 
give  it  a  finishing,  by  mending  such 
places  as  are  faulty ;  then  you  may  lay  on 
a  varnish,  and  polish  it  in  the  best  man- 
ner you  can. 

MA RiNE  ACID.  See  Muriatic  Acid. 
MARINER'S  COMPASS.    See  Mac 

XETISM. 

MARL.    See  Agriculture. 
MARMALADE,    SCOTCH— Of  the 
different  kinds  of  Marmalade,  the  Scotch 
is  preferred.    It  is  prepared  thus  : 

T;ike  the  same  weight  of  oranges,  as  of 
sugar;  grate  one  half  of  the  roughest 
part  of  the  oranges,  and  pour  boiling  wa- 
ter  over  them.  Cut  the  fruit  across  as 
a  lemon  for  punch,  and  squeeze  them 
through  a  sieve,  boil  the  skins  tender,  and 
scrape  the  inside  all  out ;  then  cut  them 
into  very  small  chips,  and  let  them  boil 
until  they  are  transparent.  Then  put  in 
the  juice,  and  the  water  strained  from  the 
gratings,  and  let  all  boil  together  until 
the  juice  jellies,  which  you  will  know  by 
cooling  a  little  of  it  in  a  saucer. 

MARTIAL  VITRIOL.  See  Copper- 
as, Iron- 

MASSICOT.    See  Lead. 

MASTICH  VARNISH  See  Varxisii. 

MASTICH. 

The  pistachia  lentiscus  is  a  small  tree, 
about  ten  or  twelve  feet  high,  that  grows 
in  several  of  the  islands  of  the  Archipe- 
lago, but  is  cultivated  with  peculiar  care 
and  success  in  the  island  of  Chio.  In  the 
month  of  August  transverse  incisions  are 
made  in  the  bark  of  this  tree,  from  which 
there  oozes  out,  in  the  space  of  a  few 


MAS 


ME  A 


hours,  a  pellucid  resin.  This  resin  is 
called  mastich,  and  when  pure  is  in  the 
form  of  little  round  drops  or  tears,  of  a 
very  pale  amber  colour  ;  a  piece  recently 
broken  is  quite  transparent,  but  by  expo- 
sure to  the  air  it  becomes  somewhat  pul- 
verulent superficially,  and  hence  semitran- 
sparent.  Its  specific  gravity  is  1.074.  This 
ri'Mii,  especially  when  gently  warmed,  has 
a  faint  but  not  unpleasant  odour,  which 
becomes  stronger  and  more  grateful  when 
it  is  melted;  it  has  scarcely  any  sensible 
flavour;  when  masticated  it  grows  soft 
like  wax,  and  acquires  an  ivory  white- 
ness ;  water  boiled  upon  it  becomes  im- 
pregnated with  its  odour,  but  the  mastich 
loses  hardly  any  weight  by  the  process. 

By  digestion  with  alcohol  it  is  separat- 
ed into  two  portions ;  the  one  soluble  in 
this  fluid,  and  the  other  insoluble  ;  the  for- 
mer composes  about  |  of  the  whole,  and 
is  pure  rosin  ;  the  latter  in  most  of  its 
properties  closely  resemble  caoutchouc. 
The  presence  of  this  substance  in  mastich 
was  first  remarked  by  Kunde,  an  apothe- 
cary of  Berlin,  whose  observations  have 
since  been  confirmed  by  Mr.  Matthews. 
After  solution  of  the  resin  in  alcohol,  an 
infiammable  residue  is  left  behind,  of  a 
white  colour,  considerably  elastic  and  ad- 
hesive ;  when  heated  it  becomes  brown, 
emitting  an  infiammable  gas,  and  in  this 
state  greatly  resembles  common  caout- 
chouc, except  in  being  slightly  glutin- 
ous. It  is  perfectly  soluble  in  washed 
sulphuric  ether,  from  which  it  is  precipi- 
table  by  alcohol  in  the  form  of  a  white 
curd.    It  is  wholly  insoluble  in  water. 

In  the  Turkish  dominions  mastich  is  in 
great  request  among  the  women,  as  a 
masticatory,  and  the  produce  of  the  Chi- 
an  plantations  is  said  to  be  appropriated 
to  the  use  of  the  emperor's  seraglio.  In 
the  other  countries  of  Europe  it  is  employ- 
ed medicinally  in  fumigations,  and  by  paint- 
ers and  other  artists  in  the  composition 
of  the  tougher  kinds  of  varnishes. 

MASHING.    See  Brewing. 

MASHING  MACHINE,  American.— 
The  following  patented  machine  for 
mashing,  obtained  by  Mr.  Ellis  of  New- 
Jersey,  we  thought  worth  noticing,  as 
much  labour  and  expense  is  saved  by  its 
use. 

The  principal  parts  of  this  machine 
consist  of  two  horizontal  rollers,  one 
above  the  other,  which  move  on  pivots  in 
the  extremities  of  two  perpendicular 
bars ;  round  the  rollers  move  one  or  more 
bands,  having  rakes  fastened  to  them, 
which  by  the  turning  of  the  bands  move 
upwards  and  downwards,  thereby  mash- 
ing the  malt.   One  of  the  perpendicular 


bars  moves  on  a  pivot  in  the  centre  of  the 
malt  tub,  and  receives  its  motion  from  a 
cog  wheel  at  the  extremity  of  the  upper 
roller,  moving  in  a  double  cog  wheel, 
above  the  centre  of  which  is  the  perpen- 
dicular bar  in  the  middle  of  the  tub  :  the 
upper  cogs  of  the  last  mentioned  wheel 
move  in  cogs  at  the  extremity  of  the 
shaft  which  receives  its  motion  from  a 
horse  or  other  power. 

MATCHING.  A  method  of  preparing 
vessels  for  the  preservation  of  wines,  cy- 
der, or  similar  liquors,  from  becoming 
sour.  It  is  effected  in  the  following  man- 
ner :  Let  any  quantity  of  sulphur  be  melt- 
ed in  an  iron  ladle ;  and,  as  soon  as  it  is 
liquefied,  slips  of  coarse  linen  cloth  are 
to  be  dipped  in  it ;  which,  when  taken  out 
and  cooled,  are  called  matches.  One  of 
these  slips  is  now  to  be  lighted,  and  sus- 
pended in  the  bung-hole  of  a  cask,  which 
ought  to  be  slightly  stopped,  till  the 
match  is  consumed ;  when  the  hole  may 
be  closed,  and  the  vessel  be  suffered  to 
stand  for  one  or  two  hours.  On  opening 
the  bung-hole,  it  will  be  found  that  the 
sulphur  has  communicated  to  the  whole 
cask  a  very  pungent,  though  suffocating 
and  acid,  odour. 

The  vessel  may  next  be  filled  with  small 
wine,  newly  fermented  ;  and,  on  carefully 
closing  it,  the  liquor  will  speedily  clarify. 
This  method  is  very  commonly  practised 
in  different  parts  of  England,  and  is  said 
to  be  very  useful ;  as  many  poor  wines 
may  thus  be  preserved  potable  for  a  con- 
siderable time.  We  doubt,  however,  its 
salubrity  ;  and  conceive  that  other  arti- 
cles might  be  advantageously  employed 
instead  of  the  pernicious  fumes  of  sul- 
phur, which  render  both  wine  and  cyder 
alike  unwholesome,  especially  for  persons 
affected  with  diseases  of  the  breast  or 
lungs. 

MEAD,  ORANGE,  to  make.— Commu 
nicated  by  Dr.  Mease. 

Take  of  honey  681b.  soft  water  17  gal- 
lons, whites  of  12  eggs,  beat  up  with  a 
quart  of  the  above  iiquor,  while  cold. 
Boil  the  whole  for  an  hour,  skimming  if 
from  time  to  time.  Then  pour  the  boiling 
liquor  on  the  thin  rinds  of  1  doz.  of  Se- 
ville oranges,  and  cover  it  up.  "When  it 
is  about  lukewarm,  add  the  juice  of  8 
doz.  of  Seville  oranges,  and  of  6  lemons 
and  their  thin  rinds.  Stir  the  whole  well, 
and  cover  it  till  it  is  cooled  clown  to  96° 
of  Farenheit's  thermometer,  when  a  pint 
of  good  ale  yeast  is  to  be  put  on  a  toast, 
and  added  to  it.  After  it  has  fermented 
two  or  three  days,  or  till  the  froth  begins 
to  sink,  then  strain  it  off*  from  the  press 
into  a  clean  cask,  and  let  it  stand  6  months 


MFX 


MEC 


before  it  is  bottled.  Draw  it  off  carefully 
with  a  syphon,  without  disturbing-  the 
grounds.    See  Hydro m el. 

MECHANICAL  POWERS  — The  me- 
chanical powers  are  simple  engines,  that 
enable  men  to  raise  weights,  move  heavy 
bodies,  and  overcome  resistances,  which 
they  could  not  do  with  their  natural 
strength  alone. 

Their  importance  to  society  is  incalcu- 
lable. Every  machine  whatever  is  com- 
posed of  one  or  more  of  them ;  some- 
times of  several  combined  together. 

In  considering-  this  science,  it  will  be 
necessary  at  first  to  take  some  things  for 
granted  that  are  not  strictly  true  ;  and  af- 
ter the  theory  is  established,  to  make  the 
proper  allowances  for  them. 

1.  That  a  small  portion  of  the  earth's 
surface,  which  is  spherical,  may  be  con- 
sidered as  a  plane. 

2.  That  all  bodies  be  supposed  to  de- 
scend in  lines  parallel  to  each  other ;  for 
though  all  bodies  really  tend  to  the  cen- 
tre of  the  earth,  yet  the  distance  from 
which  they  fall  is  comparatively  so  small, 
that  their  inclination  towards  each  other 
is  inconsiderable. 

3.  That  all  planes  be  considered  as 
perfectly  smooth  ;  levers  to  be  inflexible, 
and  w  ithout  thickness  or  weight ;  cords 
perfectly  pliable ;  and  machines  without 
friction  and  inertia. 

Three  things  are  always  to  be  consider- 
ed in  treating  of  mechanical  engines  :  the 
weight  to  be  raised  ;  the  power  by  which 
it  is  to  be  raised ;  and  the  instrument  or 
engine  by  which  this  is  to  be  effected. 

The  mechanical  powers  are  generally 
reckoned  six ;  the  lever,  the  pulley,  the 
wheel  and  axis,  the  inclined  plane,  the 
wedge,  and  the  screw. 

These  perhaps  may  be  reduced  to  two ; 
for  the  pulley  and  wheel  are  only  assem- 
blages of  levers,  and  the  wedge  and  screw 
are  inclined  planes. 

To  calculate  the  power  of  a  machine, 
it  is  usually  considered  in  a  state  of  equi- 
librium ;  that  is,  in  the  state  when  the 
power  which  is  to  overcome  the  resist- 
ance, just  balances  it.  Having  discover- 
ed what  quantity  of  power  will  be  requi- 
site for  this  purpose,  it  will  then  be  ne- 
cessary to  add  so  much  more  as  to  over- 
come the  friction  and  weight  of  the  ma- 
chine itself,  and  to  give  the  necessary  ve- 
locity. 

Of  the  Lever. — The  lever  is  the  sim- 
plest of  all  machines,  and  is  only  a  straight 
bar  of  iron,  wood,  or  other  material,  sup- 
ported on,  and  moveable  round,  a  prop 
called  the  fulcrum. 

In  the  lever,  there  are  three  circum- 
stances to  be  principally  attended  to  :  1. 


The  fulcrum,  or  prop,  by  which  it  is  sup- 
ported, or  on  which  it  turns  as  an  axis,  or 
centre  of  motion  :  2.  The  power  to  raise 
and  support  the  weight :  3.  The  resist- 
ance or  weight  to  be  raised  or  sustained. 

The  points  of  suspension  are  those 
points  where  the  weights  really  are,  or 
from  which  they  hang  freely. 

The  power  and  the  weight  are  always 
supposed  to  act  at  right  angles  to  the  le- 
ver, except  it  be  otherwise  expressed. 

The  lever  is  distinguished  into  three 
sorts,  according  to  the  different  situations 
of  the  fulcrum,  or  prop,  and  the  power, 
with  respect  to  each  other. 

1.  When  the  prop  is  placed  between 
the  power  and  the  weight. 

2.  When  the  prop  is  at  one  end  of  the 
lever,  the  power  at  the  other,  and  the 
weight  between  them. 

3.  When  the  prop  is  at  one  end,  the 
weight  at  the  other,  and  the  power  ap- 
plied between  them. 

A  poker,  in  stirring  the  fire,  is  a  lever 
of  the  first  sort ;  the  bar  of  the  grate  up- 
on which  it  rests  is  the  fulcrum ;  the  fire, 
the  weight  to  be  overcome ;  and  the  hand 
is  the  power.  The  lever  of  the  first  kind 
is  principally  used  for  loosening  large 
stones  ;  or  to  raise  great  weights  to  small 
heights,  in  order  to  get  ropes  under  them, 
or  other  means  of  raising  them  to  still 
greater  heights  :  it  is  the  most  common 
species  of  lever. 

ABC  (Plate  I.  fig.  6)  is  this  lever ;  in 
which  B  is  the  fulcrum,  A  the  end  at 
which  the  power  is  applied,  and  C  the 
end  where  the  weight  acts. 

To  find  when  an  equilibrium  will  take 
place  between  the  power  and  the  weight, 
in  this  as  well  as  in  every  other  species  of 
lever,  it  is  necessary  to  recur  to  what  has 
formerly  been  mentioned ;  that  when  the 
momenta,  or  quantities  of  force,  in  two 
bodies  were  equal,  they  would  balance 
each  other.  Now,  let  us  consider  when 
this  will  take  place  in  the  lever.  Sup- 
pose the  lever  AB  (fig.  7)  to  be  turned  on 
its  axis,  or  fulcrum,  so  as  to  come  into 
the  situation  DC  ;  as  the  end  D  is  farthest 
from  the  centre  of  motion,  and  as  it  has 
moved  through  the  arch  AD  in  the  same 
time  as  the  end  B  moved  through  the 
arch  BC,  it  is  evident  that  the  velocity  of 
AB  must  have  been  greater  than  that  of 
B.  But  the  momenta  being  the  products 
of  the  quantities  of  matter  multiplied  in- 
to the  velocities,  the  greater  the  velocity, 
the  less  the  quantity  of  matter  need  be 
to  get  the  same  product.  Therefore,  as 
the  velocity  of  A  is  the  greatest,  it  will 
require  less  matter  to  produce  an  equili- 
brium than  B. 

Let  us  next  see  how  much  more  weight 


MEC 


MEC 


B  will  require  than  A,  to  balance.  As 
the  radii  of  circles  are  in  proportion  to 
their  circumferences,  they  a»  e  also  propor- 
tionate to  similar  parts  of  them ;  there- 
fore, as  the  arches  AO,  CB,  are  similar, 
the  radius,  or  arm,  DE,  bears  the  same 
proportion  to  EC  that  the  arch  AD  bears  to 
CB.  But  the  arches  AD  and  CB  represent 
the  velocities  of  the  ends  of  the  lever,  be- 
cause they  are  the  spaces  which  they 
moved  over  in  the  same  time;  therefore 
the  ams  DE  and  EC  may  also  represent 
these  veloeities. 

It  is  evident  then,  that  an  equilibrium 
will  take  place,  when  the  length  of  the 
arm  AE,  multiplied  into  the  power  A, 
shall  equal  EB,  multiplied  into  the  weight 
B ;  and  consequently,  that  the  shorter 
EB  is,  the  greater  must  be  the  weight  B; 
that  is,  the  power  and  the  weight  must 
be  to  each  other  inversely,  as  their  dis- 
tances from  the  fulcrum.  Thus,  suppose 
AE,  the  distance  of  the  power  from  the 
prop,  to  be  twenty  inches,  and  EB,  the 
distance  of  the  weight  from  the  prop,  to 
be  eight  inches,  also  the  weight  to  be 
raised  at  B  to  be  five  pounds ;  then  the 
power  to  be  applied  at  A,  must  be  two 
pounds ;  because  the  distance  of  the 
weight  from  the  fulcrum  eight,  multiplied 
into  the  weight  five,  makes  forty ;  there- 
fore twenty,  the  distance  of  the  power 
from  the  prop,  must  be  multiplied  by  two, 
to  get  an  equal  product ;  which  will  pro-? 
duce  an  equilibrium. 

It  is  obvious,  that  while  the  distance  of 
the  power  from  the  prop  exceeds  that  of 
the  weight  from  the  prop,  a  power  less 
than  the  weight  will  raise  it,  so  that  then 
the  lever  affords  a  mechanical  advantage: 
when  the  distance  of  the  power  is  less 
than  that  of  the  weight  from  the  prop, 
the  power  must  be  greater  than  the 
weight  to  raise  it;  when  both  the  arms 
are  equal,  the  power  and  the  weight  must 
be  equal,  to  be  in  equilibrio. 

The  second  kind  of  lever,  when  the 
weight  is  between  the  fulcrum  and  the 
power,  is  represented  by  Fig.  8,  Plate  I. 
in  which  A  is  the  fulcrum,  B  the  weight, 
and  C  the  power.  The  advantage  gained 
by  this  lever,  as  in  the  first,  is  as  great 
as  the  distance  of  the  power  from  the 
prop  exceeds  the  distance  of  the  weight 
from  it.  Thus,  if  the  point  a,  on  which 
the  power  acts,  be  seven  times  as  far  from 
A  as  the  point  Z,  on  which  the  weight 
acts,  then  one  pound  applied  at  C  will 
raise  seven  pounds  at  B. 

1'his  lever  shows  the  reason  why  two 
men  carrying  a  burden  upon  a  stick  be- 
tween them,  bear  shares  of  the  burden 
which  are  to  one  another  in  the  inverse 
proportion  of  their  distances  from  it.  For 
VOL.  II. 


«t  is  well  known,  that  the  nearer  either 
of  them  is  to  the  burden,  the  greater  share 
he  bears  of  it;  and  if  he  go  directly  under 
it,  he  bears  the  whole.  So  if  one  man  be 
at  A,  and  the  other  at  a,  having  the  pole 
or  stick  resting  on  their  shoulders  ;  if  the 
burden  or  weight  B  be  placed  five  times 
as  near  the  man  at  A,  as  it  is  to  the  man 
a,  the  former  will  bear  five  times  as  much 
weight  as  the  latter. 

This  is  likewise  applicable  to  the  case 
of  two  horses  of  unequal  strength  to  be 
so  yoked,  as  that  each  horse  may  draw  a 
part  proportionable  to  his  strength ;  which 
is  done  by  so  dividing  the  beam  they  pull, 
that  the  point  of  traction  may  be  as  much  / 
nearer  to  the  stronger  horse  than  to  the 
weaker,  as  the  strength  of  the  former  ex- 
ceeds that  of  the  latter. 

To  this  kind  of  lever  may  be  reduced 
oars,  rudders  of  ships,  doors  turning  upon 
hinges,  cutting-knives  which  are  fixed,  at 
the  point,  &c. 

If  in  this  lever  we  suppose  the  power 
and  weight  to  change  places,  so  that  the 
power  may  be  between  the  weight  and 
the  prop,  it  will  become  a  lever  of  the 
third  kind ;  in  which,  that  there  may  be 
a  balance  between  the  power  and  the 
weight,  the  intensity  of  the  power  must 
exceed  the  intensity  of  the  weight  just  as 
much  as  the  distance  of  the  weight  from 
the  prop  exceeds  the  distance  of  the  pow- 
er. Thus,  let  E,  (Fig.  9.)  be  the  prop  of 
the  lever  EF,  and  W  a  weight  of  one 
pound,  placed  three  times  as  far  from  the 
prop  as  the  power  P  acts  at  F,  by  the 
cord  going  over  the  fixed  pulley  D :  in 
this  case,  the  power  must  be  equal  to 
three  pounds,  in  order  to  support  the 
weight  of  one  pound. 

To  this  sort  of  lever  are  generally  re- 
ferred the  bones  of  a  man's  arm  ;  for  when 
he  lifts  a  weight  by  the  hand,  the  muscle 
that  exerts  its  force  to  raise  that  weight, 
is  fixed  to  the  bone  about  one  tenth  part 
as  far  below  the  elbow  as  the  hand  is. 
And  the  elbow  being  the  centre  round 
which  the  lower  part  of  the  arm  turns, 
the  muscle  must  therefore  exert  a  force 
ten  times  as  great  as  the  weight  that  is 
raised. 

As  this  kind  of  lever  is  a  disadvantage 
to  the  moving  power,  it  is  used  as  little 
as  possible ;  but  in  some  cases  it  cannot 
be  avoided;  such  as  that  of  a  ladder, 
which  being  fixed  at  one  end,  is  by  the 
strength  of  a  man's  arms  reared  against 
a  wall. 

What  is  called  the  hammer. lever,  dif- 
fers in  nothing  but  its  form,  from  a  lever 
of  the  first  kind.  Its  name  is  derived  from 
its  use,  that  of  drawing  a  nail  out  of  wood 
by  a  hammer. 

H 


MEC 


MEC 


Suppose  the  shaft  of  a' hammer  to  be  I 
five  times  as  long  as  the  iron  part  which 
dra  \vs  the  nail,  the  lower  part  resting-  on 
the  board,  as  a  fulcrum  ;  then,  by  pulling 
backwards  the  end  of  the  shaft,  a  man 
will  draw  a  nail  with  one-fifth  part  oi  the 
power  that  he  must  use  to  pull  it  out  with 
a  pair  of  pincers  ;  in  which  case,  the  nail 
would  move  as  fast  as  his  hand ;  but  with 
the  hammer,  the  hand  moves  five  times 
as  much  as  the  nail,  by  the  time  that  the 
nail  is  drawn  out. 

Let  ACB  (Fig.  10.)  represent  a  lever  of 
this  sort,  bended  at  C,  which  is  its  prop, 
or  centre  of  motion  P  is  a  power  acting 
upon  the  longer  arm  AC,  at  A,  by  means 
of  the  cord  DA  going  over  the  pulley  D; 
and  AV  is  a  weight  or  resistance  acting 
upon  the  endB  of  the  shorter  arm  CB.  If 
the  power  be  to  the  weight  as  CB  is  to 
CA,  they  are  in  equilibrio  :  thus,  suppose 
W  to  be  five  pounds,  acting  at  the  dis- 
tance of  one  foot  from  the  centre  of  mo- 
tion C,  and  P  to  be  one  pound,  acting  at 
A,  five  feet  from  the  centre  C,  the  power 
and  weight  will  just  balance  each  other. 

Thus"  we  see,  that  in  every  species  of 
lever  there  will  be  an  equilibrium,  when 
the  power  is  to  the  weight  as  the  distance 
of  the  weight  from  the 'fulcrum  is  to  the 
distance  of  the  power  from  the  fulcrum 

In  making  experiments  on  the  mecha- 
nic powers,  some  difficulties  arise  from 
the  weight  of  the  materials  ;  but  as  it  is 
impossible  to  find  any  that  are  without 
weight,  we  take  care  that  they  are  per- 
fectly balanced  themselves,  before  the 
weights  and  powers  are  applied.  The 
bar,  therefore,  used  in  making  experi- 
ments on  levers,  has  the  short  end  so 
much  thicker  than  the  long  arm,  as  will 
be  sufficient  to  balance  it  on  the  prop 

If  the  weight  to  be  raised  be  of  consi- 
derable bulk,  and  if  it  be  fixed  either 
above  or  below  the  end  of  the  lever,  it 
will  vary  in  its  intensity,  according  to  the 
position  of  the  lever.  Let  AB  (Fig  11.) 
represent  a  lever  having  a  weight  fixed 
above  it,  as  A,  of  which  the  centre  of  gra- 
vity is  a,  and  the  line  of  direction  a  b ; 
then  is  b  the  point  in  the  lever  on  which 
the  weight  acU  :  but  if  the  lever  is  moved 
into  the  position  CD,  the  line  of  direction 
of  the  weight  will  fall  nearer  to  the  ful- 
crum of  the  lever,  and  consequently  act 
with  less  force  upon  it ;  tut  if  it  is  placed 
in  the  position  EF,  the  line  of  direction 
will  fall  farther  from  the  fulcrum,  and 
therefore  act  more  on  the  lever. 

On  the  contrary,  it  is  evident  from  Fig. 
12,  that  opposite  effects  take  place,  when 
the  weight  is  below  the  lever. 

Nothing  of  this  kind  can  happen,  when 
tbe  weight  is  suspended  from  the  lever  by 


a  rope,  because  the  point  of  suspension, 
or  point  of  action,  is  not  altered. 

When  two  draymen  carry  a  barrel  on  a 
coulstaff,  to  which  it  is  s  spended  by  a 
chain,  the  point  on  which  'he  weight  acts 
n  t  being  altered  by  inclining  the  SvafT 
in  going  up  or  down  hill,  there  will  be  no 
variation  in  the  weight  that  each  man  had 
to  support  on  beginning  But  if  they  carry 
the  barrel  upon  two  dogs,  then  the  weight 
does  not  swing,  and  the  centre  of  gravity 
is  below  the  lever ;  therefore  the  point  on 
which  the  weight  acts,  will,  by  inclining 
the  lever,  be  made  to  approach  the  high- 
est end  ;  and  the  first  man,  in  going  down 
hill,  by  having  this  point  removed  from 
him,  will  be  eased  in  part  of  his  burden  , 
and  the  last  man  will  have  his  equally  in- 
creased. 

Hitherto  we  have  supposed  that  the 
power  and  weight  acted  perpendicularly 
upon  the  lever :  but  if  they  do  not,  they 
act  with  less  force  upon  it ;  the  power 
should,  therefore,  if  possible,  be  always 
made  to  act  at  right  angles  to  the  lever. 

If  several  levers  be  combined  together 
in  such  a  manner,  as  that  a  weight  being 
appended  to  the  first  lever,  may  be  sup- 
ported by  a  power  applied  to  the  last,  as 
in  Fig.  12,  Plate  I.  which  consists  of  three 
levers  of  the  first  kind,  and  is  so  contri- 
ved, that  a  power  applied  at  the  point  L 
of  the  lever  C,  may  sustain  a  weight  at 
the  point  S  of  the  lever  A,  the  power 
must  here  be  to  the  weight,  in  a  ratio,  or 
proportion,  compounded  of  the  several 
ratios,  which  those  powers  that  can  sus- 
tain the  weight  by  the  help  of  each  1  ver, 
when  used  singly  and  apart  from  the  rest, 
have  to  the  weighs  For  instance,  if  the 
power  which  can  sustain  the  weight  P, 
by  the  help  of  the  lever  A,  be  to  the 
weight  as  1  to  5  ;  and  if  the  power  which 
can  sustain  the  same  weight,  by  the  lever 
B  alone,  be  to  the  weight  as  1  to  4 ;  and 
if  the  power  which  could  sustain  the  same 
weight  by  the  lever  C,  be  to  the  weight 
as  1  to  5 ;  then  the  power  wrhich  will  sus- 
tain the  weight  by  help  of  the  three  leveri 
joined  together,  will  be  to  the  weight  in 
a  proportion  consisting  of  the  several  pro- 
portions multiplied  together,  of  1  to  5,  1 
to  4,  and  1  to  5 ;  that  is  of  1  to  100. 

For  since,  in  the  lever  A,  a  power 
equal  to  one-fifth  of  the  weight  P  press- 
ing down  the  lever  at  L,  is  sufficient  to 
balance  the  weight,  and  since  it  is  the 
same  tiling  whether  that  power  be  ap- 
plied to  the  lever  A  at  L,  or  the  lever  B 
at  S,  the  point  S  bearing  on  the  point  L, 
a  power  equal  to  one-fifth  of  the  weigh  t 
P,  being  applied  to  the  point  S  of  the  le- 
ver B,  will  support  the  weight;  but  one- 
fourth  of  the  same  power  being  applied  to 


J.ff.  Seymi'W  .<v. 


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MEC 


the  point  L  of  the  lever  B,  and  pushing 
the  same  upward,  will  as  effectually  de- 
press the  point  S  of  the  same  lever,  as  if 
the  whole  power  were  applied  at  S  ;  con- 
sequently a  power  equal  to  one-fourth  of 
one-fifth,  that  is,  one-twentieth  of  the 
weight  P,  being  applied  to  the  point  L  of 
the  lever  B,  and  pushing  up  the  same, 
will  support  the  weight :  in  like  manner, 
it  matters  not  whether  that  force  be  ap- 
plied to  the  point  L  of  the  lever  B,  or  to 
the  point  S  of  the  lever  C,  since,  if  S  be 
raised,  L,  which  rests  on  it,  must  be 
raised  also ;  but  one-fifth  of  the  power 
applied  at  the  point  L  of  the  lever  C,  and 
pressing  it  downwards,  will  as  effectually 
raise  the  point  S  of  the  same  lever,  as  if 
the  whole  power  were  applied  at  S,  and 
pushed  up  the  same  ;  consequently  a  pow- 
er equal  to  one-fifth  of  one-twentieth,  that 
is,  one-hundredth  part  of  the  weight  P, 
being  applied  to  the  point  L  of  the  lever 
C,  will  balance  the  weight  at  the  point  S 
of  the  lever  A. 

This  method  of  combining  levers,  is 
frequently  used  in  maehines  and  instru- 
ments, and  is  of  great  service,  either  in 
obtaining  a  greater  power,  or  in  applying 
it  with  more  convenience. 

The  balance,  an  instrument  of  very 
extensive  use  in  comparing  the  weights 
of  bodies  is  a  lever  of  the  first  kind, 
whose  arms  are  of  equal  length. — 
The  points  from  which  the  weights  are 
suspended  being  equally  distant  from  the 
centre  of  motion,  will  move  with  equal  ve- 
locity ;  consequently,  if  equal  weights  be 
applied,  their  momenta  will  be  equal,  and 
the  balance  will  remain  in  equilibrio. 

In  order  to  have  a  balance  as  perfect  as 
possible,  it  is  necessary  to  attend  to  the 
following  circumstances  : 

1.  The  arms  of  the  beam  ought  to  be 
exactly  equal,  both  as  to  weight  and 
length. 

2.  The  points  from  which  the  scales  are 
suspended,  should  be  in  a  right  line,  pass- 
ing through  the  centre  of  gravity  of  the 
beam  ;  for  by  this,  the  weights  will  act 
directly  against  each  other,  and  no  part  of 
either  will  be  lost,  on  account  of  any  ob- 
lique direction. 

3.  If  the  fulcrum,  or  point  upon  which 
the  beam  turns,  be  placed  in  the  centre  of 
gravity  of  the  beam,  and  if  the  fulcrum 
and  the  points  of  suspension  be  in  the 
same  right  line,  the  balance  will  have  no 
tendency  to  one  position  more  than  ano- 
ther, but  will  rest  in  any  position  it  may 
be  placed  in,  whether  the  scales  be  on  or 
off,  empty  or  loaded. 

If  the  centre  of  gravity  of  the  beam, 
when  level,  be  immediately  above  the  ful- 
crum, it  will  overset  by  the  smallest  ac- 


tion ;  that  is,  the  end  which  is  lowest  will 
descend ;  and  it  will  do  this  with  more 
swiftness,  the  higher  the  centre  of  gravi- 
ty be,  and  the  less  the  points  of  suspen- 
sion be  loaded. 

But  if  the  centre  of  gravity  of  the  beam 
be  immediately  below  the  fulcrum,  the 
beam  will  not  rest  in  any  position  but 
when  tevel ;  and  if  disturbed  from  that  po- 
sition, and  then  left  at  liberty,  it  will  vi- 
brate, and  at  last  come  to  rest  on  the  le- 
vel. In  a  balance,  therefore,  the  fulcrum 
ought  always  to  be  placed  a  little  above  the 
centre  of  gravity.  Its  vibrations  will  be 
quicker,  and  its  horizontal  tendency 
stronger,  the  lower  the  centre  of  gravity, 
and  the  less  the  weight  upon  the  points  of 
suspension. 

4.  The  friction  of  the  beam  upon  the 
axis  ought  to  be  as  little  as  possible;  be- 
cause, should  the  friction  be  great,  it  will 
require  a  considerable  force  to  overcome 
it;  upon  which  account,  though  one 
weight  should  a  little  exceed  the  other,  it 
will  not  preponderate,  the  excess  not  be- 
ing sufficient  to  overcome  the  friction, 
and  bear  down  the  beam.  The  axis  of 
motion  should  be  formed  with  an  edge 
like  a  knife,  and  made  very  hard  :  these 
edges  are  at  first  made  sharp,  and  then 
rounded  with  a  fine  hone,  or  piece  of  buff 
leather,  which  causes  a  sufficient  blunt- 
ness,  or  rolling  edge/  On  the  regular 
form  and  excellence  of  this  axis,  depends 
chiefly  the  perfection  of  this  instrument. 

5.  The  pivots,  which  form  the  axis  or 
fulcrum,  should  be  in  a  straight  line,  and 
at  right  angles  to  the  beam. 

6.  The  arms  should  be  as  long  as  pos- 
sible, relatively  to  their  thickness,  and  the 
purposes  for  which  they  are  intended,  as 
the  longer  they  are,  the  more  sensible  is 
the  balance. 

They  should  also  be  made  as  stiff  and 
inflexible  as  possible  ;  for  if  the  beam  be 
too  weak,  it  will  bend,  and  become  untrue. 

7.  The  rings,  or  the  piece  on  which  the 
axis  bears,  should  be  hard  and  well  po- 
lished, parallel  to  each  other,  and  of  an 
oval  form,  that  the  axis  may  always  keep 
its  proper  bearing,  or  remain  always  at  the 
lowest  point. 

8.  If  the  arms  of  a  balance  be  unequal, 
the  weights  in  equipoise  will  be  unequal 
in  the  same  proportion.  The  equality  of 
the  arms  is  of  use,  in  scientific  pursuits, 
chiefly  in  the  making  of  weights  by  bisec- 
tion. A  balance  with  unequal  arms  will 
weigh  as  accurately  as  another  of  the 
same  workmanship  with  equal  arms,  pro- 
vided the  standard  weight  itself  be  first 
counterpoised,  then  taken  out  of  the 
scale,  and  the  thing  to  be  weighed  be  put 
into  the  scale,  and  adjusted  against  the 


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MEC 


counterpoise.  Or,  when  proportional 
Quantities  only  are  considered,  the  bodies 
under  examination  may  be  weighed 
against  the  weights,  taking  care  always  to 
put  the  weights  in  the  same  scale ;  for 
then,  though  the  bodies  may  not  be  really 
equal  to  the  weights,  yet  their  proportions 
amongst  each  other  will  be  the  same  as  if 
they  had  been  accurately  so.  * 

9.  Very  delicate  balances  are  not  only 
useful  in  nice  experiments,  but  are  like- 
wise much  more  expeditious  than  others 
in  common  weighing.  If  a  pair  of  scales, 
with  a  certain  load  be  barely  sensible  to 
one-tenth  of  a  grain,  it  will  require  a  con- 
siderable time  to  ascertain  the  weight  to 
that  degree  of  accuracy,  because  the  turn 
must  be  observed  several  times  over,  and 
is  very  small.  But  if  no  greater  accuracy 
were  required,  and  scales  were  used, 
which  would  turn  with  one-hundredth  of 
a  grain,  a  tenth  of  a  grain  more  or  less, 
would  make  so  great  a  difference  in  the 
turn,  that  it  would  be  seen  immediately. 

10.  If  a  balance  be  found  to  turn  With  a 
certain  addition,  and  is  not  moved  by  any 
smaller  weight,  a  greater  sensibility  may 
be  given  to  the  balance,  by  producing  a 
tremulous  motion  in  its  parts.  Thus,  if 
the  edge  of  a  blunt  saw,  a  file,  or  other  si- 
milar instrument,  be  drawn  along  any  part 
of  the  case  or  support  of  the  balance,  it 
will  produce  a  jarring,  which  will  dimin- 
ish the  friction  in  the  moving  parts  so 
much,  that  the  turn  will  be  evident  with 
one-third,  or  one-fourth  of  the  addition 
that  would  else  have  been  required.  In 
this  way,  a  beam  which  would  barely  turn 
by  the  addition  of  the  tenth  of  a  grain, 
will  turn  with  the  thirtieth  or  fortieth  of 
a  grain. 

To  those  who  are  engaged  in  making 
nice  philosophical  experiments,  an  accu- 
rate balance  is  of  the  greatest  importance. 
One  of  the  best  ever  made,  is  that  belong- 
ing to  the  Royal  Society,  executed  by  the 
late  Mr.  Ramsden. 

The  statera,  or  Roman  steel-yard,  is  a 
lever  of  the  first  kind,  and  is"  used  for 
finding  the  weights  of  different  bodies,  by 
one  single  weight  placed  at  different  dis- 
tances from  the  prop  or  centre  of  motion 
D  (Fig.  14.)  Plate  I.  For,  the  shorter  arm 
!CG  is  of  such  a  weight  as  exactly  to  coun- 
terpoise the  longer  arm  DX.  If  this  arm 
be  divided  into  as  many  equal  parts  as  it 
will  contain,  each  equal  to  GD,  the  single 
weight  P  (which  we  may  suppose  to  be 
one  pound)  will  serve  for  weighing  any 
thing  as  heavy  as  itself,  or  as  many  times 
heavier  as  there  are  divisions  in  the  arm 
DX,  or  any  quantity  between  its  own 
weight  and  that  quantity.  As  for  exam- 
ple, if  P  be  one  pound,  and  placed  at  the 


first  division  1  in  the  arm  DX,  it  will  ba- 
lance  one  pound  in  the  scale  at  W ;  if  it  be 
removed  to  the  second  division  at  2,  it 
will  balance  two  pounds  in  the  scale ;  if 
to  the  third,  three  pounds  ■  and  so  on  to 
the  end  of  the  arm  DX.  If  any  of  these 
integral  divisions  be  subdivided  into  as 
many  equal  parts  as  a  pound  contains 
ounces,  and  the  weight  P  be  placed  at 
any  of  these  subdivisions,  so  as  to  counter- 
poise what  is  in  the  scale,  the  pounds  and 
odd  ounces  therein  will  by  that  means  be 
ascertained. 

Of  the  Wheel  and  Axle— -The  wheel  and 
axle  is  a  machine  much  used,  and  is  made 
in  a  variety  of  forms.  It  consists  of  a 
wheel  with  an  axle  fixed  to  it,  so  as  to  turn 
round  with  it ;  the  power  being  applied  at 
the  circumference  of  the  wheel,  the 
weight  to  be  raised  is  fastened  to  a  rope 
which  coils  round  the  axle. 

AB  (Fig.  1,  Plate  II.)  is  a  wheel,  and 
CD  an  axle  fixed  to  it,  and  which  moves 
round  with  it.  If  the  rope  which  goes 
round  the  wheel  be  pulled,  and  the  wheel 
turned  once  round,  it  is  evident  that  as 
much  rope  will  be  drawn  off  as  the  cir- 
cumference of  the  wheel ;  but  while  the 
wheel  turns  once  round,  the  axle  turns 
once  round ;  and  consequently  the  rope 
by  which  the  weight  is  suspended,  will 
wind  once  round  the  axis,  and  the  weight 
will  be  raised  through  a  space  equal  to 
the  circumference  of  the  axis. 

The  velocity  of  the  power,  therefore, 
will  be  to  that  of  the  weight,  as  the  cir- 
cumference of  the  wheel  to  that  of  the 
axis. 

That  the  power  and  the  weight  may  be 
in  equilibrio,  therefore,  the  power  must 
be  to  the  weight  as  the  circumference  of 
the  wheel  to  that  of  the  axis- 
It  is  proved  by  geometry,  that  the  cir- 
cumferences of  different  circles  bear  the 
same  proportion  to  each  other  'as  their  re- 
spective diameters  do  ;  consequently  the 
power  is  to  the  weight,  as  the  diameter 
also  of  the  axis  to  that  of  the  wheel. 

Thus,  suppose  the  diameter  of  the 
wheel  to  be  eight  inches,  and  the  diame- 
ter of  the  axis  to  be  one  inch  ;  then  one 
ounce  acting  as  the  power  P,  will  balance 
eight  ounces  as  a  weight  W  ;  and  a  small 
additional  force  will  cause  the  wheel  to 
turn  with  its  axis,  and  raise  the  weight ; 
and  for  every  inch  which  the  weight  rises, 
the  power  will  fall  eight  inches. 

The  wheel  and  axis  may  be  considered 
as  a  kind  of  perpetual  lever,  of  which  the 
fulcrum  is  the  centre  of  the  axis,  and  the 
long  and  short  arms  the  diameter  of  the 
wheel  and  the  diameter  of  the  axis.  (See 
Fig.  2,  Plate  II.) 
From  this  it  is  evident,  that  the  longer 


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MEC 


the  wheel,  and  the  smaller  the  axis,  the 

stronger  is  the  power  of  this  machine ;  but 
then  the  weight  must  rise  slower  in  pro- 
portion. 

A  capstan  is  a  cylinder  of  wood,  with 
holes  in  it,  into  which  are  put  bars,  or  le- 
vers, to  turn  it  round ;  these  are  like  the 
spokes  of  a  wheel  without  the  rim. 

Sometimes  the  axis  is  turned  by  a 
winch  fastened  to  it,  which,  in  this  re- 
spect, serves  for  a  wheel,  and  is  more 
powerful,  in  proportion  to  the  largeness 
of  the  circle  it  describes,  compared  with 
the  diameter  of  the  axle. 

When  the  parts  of  the  axis  differ  in 
thickness,  and  weights  are  suspended  at 
the  different  parts,  they  may  be  sustain 
ed  by  one  and  the  same  power  applied  to 
the  circumference  of  the  wheel,  provided 
the  product  arising  from  the  multiplica- 
tion of  the  power  into  the  diameter  of  the 
wheel,  be  equal  to  the  sum  of  the  pro- 
ducts arising  from  the  multiplication  of 
the  several  weights  into  the  diameters  of 
those  parts  of  the  axis  from  which  they 
are  suspended. 

In  considering  the  theory  of  the  wheel 
and  axle,  we  have  supposed  the  rope  that 
goes  round  the  axle  to  have  no  sensibl 
thiekness  ;  but  as  in  practice  this  cannot 
be  the  case,  if  it  is  a  thick  rope,  or  if 
there  be  several  folds  of  it  round  the  ax- 
is, you  must  measure  to  the  middle  of  the 
outside  rope,  to  obtain  the  diameter  of  the 
axis,  for  the  distance  of  the  weight  from 
the  centre,  is  increased  by  the  coiling  up 
of  the  rope. 

If  teeth  are  cut  in  the  circumference  of 
a  wheel,  and  if  they  work  in  the  teeth  of 
another  wheel  of  the  same  size  as  Fig.  3, 
Plate  II.  it  is  evident  that  both  the  wheels 
will  revolve  in  the  same  time ;  and  the 
weight  appended  to  the  axle  of  the  wheel 
B,  will  be  raised  in  the  same  time  as  if 
the  axle  had  been  fixed  to  the  wheel  A 
But  if  the  teeth  of  the  second  wheel  be 
made  to  work  in  teeth  made  in  the  axle  of 
the  first,  as  at  Fig.  4,  Plate  II.  as  ever 
part  of  the  circumference  of  the  second 
wheel  is  applied  successively  to  the  cir 
cumference  of  the  axle  of  the  first,  and 
as  the  former  is  much  greater  than  the 
latter,  it  is  evident  that  the  first  wheel 
must  go  round  as  many  times  more  than 
the  second,  as  the  circumference  of  the  se. 
cond  wheel  exceeds  that  of  the  first  axle 
In  order  to  a  balance  here,  the  power 
must  be  to  the  weight,  as  the  product  of 
the  circumferences,  or  diameters  of  the 
two  axles  multiplied  together,  is  to  the 
circumferences  or  diameters  of  the  two 
wheels. 

This  will  become  sufficiently  clear,  if  it 
be  considered  as  a  compound  lever,  which 


was  explained  above.  Instead  of  a  com- 
bination of  two  wheels,  three  or  four 
wheels  may  work  in  each  other,  or  any 
number ;  and  by  thus  increasing  the 
number  of  wheels,  or  by  proportioning 
the  wheels  to  the  axis,  any  degree  of 
power  may  be  acquired. 

To  this  sort  of  engine  belong  all  cranes 
for  raising  great  weights  ;  and  in  this 
case  the  wheel  may  have  cogs  all  round 
it,  instead  of  handles  ;  and  a  small  lan- 
thorn,  or  trundle,  may  be  made  to  work 
in  the  cogs,  and  be  turned  by  a  winch ; 
which  will  make  the  power  of  the  engine 
to  exceed  the  power  of  the  man  who 
works  it,  as  much  as  the  number  of  revo- 
lutions of  the  winch  exceeds  those  of  the 
axle  CD,  (Plate  II.  Fig  1)  when  multipli- 
ed by  the  excess  of  the  length  of  the 
winch  above  the  length  of  the  semidia- 
meter  of  the  axle,  added  to  the  semidia- 
meter  or  half-thickness  of  the  rope  K,  by 
which  the  weight  is  drawn  up.  Thus, 
suppose  the  diameter  of  the  rope  and 
axle  taken  together  to  be  13  inches,  and 
consequently  half  their  diameter  to  6^ 
inches,  so  that  the  weight  W  will  hang  at 
6^  inches  perpendicular  distance  from  be- 
low the  centre  of  the  axle.  Now,  let  us 
suppose  the  wheel  AB,  which  is  fixed  on 
the  axle,  to  have  80  cogs,  and  to  be  turn- 
ed by  means  of  a  winch  6^  inches  long, 
fixed  on  the  axle  of  a  trundle  of  eight 
staves,  or  rounds,  working  in  the  cogs  of 


the  wheel ;  here  it  is  plain,  that  the  wind 
and  trundle  would  make  ten  revolutions 
for  one  of  the  wheel  AB,  and  its  axis  CD, 
on  which  the  rope  K  winds  in  raising  the 
weight  W ;  and  the  winch  being  no  lon- 
ger than  the  sum  of  the  semi-diameters 
of  the  great  axle  and  rope,  the  trundle 
could  have  no  more  power  on  the  wheel 
than  a  man  could  have  by  pulling  it  round 
by  the  edge,  because  the  winch  would 
have  no  greater  velocity  than  the  edge  of 
the  wheel  has,  which  wre  here  suppose  to 
be  ten  times  as  great  as  the  veloc  ity  of  the 
rising  weight ;  so  that,  in  this  case,  the 
power  gained  would  be  as  is  10  to  1. 
But  if  the  length  of  the  winch  be  13 
inches,  the  power  gained  will  be  as  20  to 
1 ;  if  19£  inches  (which  is  long  enough 
for  any  man  to  work  by),  the  power  gain- 
ed will  be  as  30  to  1 ;  that  is,  a  man  could 
raise  30  times  as  much  by  such  an  engine, 
as  he  could  do  by  his  natural  strength 
without  it,  because  the  velocity  of  the 
handle  of  the  winch  would  be  30  times  as 
great  as  the  velocity  of  the  rising  weight; 
the  absolute  force  of  any  engine  being  in 
proportion  of  the  velocity  of  the  power, 
to  the  velocity  of  the  weight  raised  by  it. 
But  then,  just  as  much  power  or  advan- 
tage as  is  gained  by  the  engine,  so  much 


>  MEG 


MEC 


time  is  lost  in  working-  it ;  which  is  com- 
mon in  all  mechanical  cases  whatever. 

In  this  son  of  machines,  it  is  requisite 
to  have  a  ratchet  wheel  on  the  end  of  the 
axle  C,  with  a  catch  to  fall  into  its  teeth  ; 
which  will  at  any  time  support  the  weight, 
and  keep  it  from  descending-,  if  the  per- 
son who  turns  the  handle  should,  through 
inadvertency  or  carelessness,  quit  his  hold 
while  the  weight  is  raising.  By  this 
means,  the  danger  is  prevented,  which 
might  otherwise  happen  by  the  running 
down  of  the  weight  when  left  at  liberty. 

Of  the  Pulley.— The  pulley  is  a  small 
wheel  turning  on  an  axis,  with  a  drawing 
rope  passing  over  it :  the  small  wheel  is 
usually  called  a  sheeve,  and  is  so  fixed  in 
a  box,  or  block,  as  to  be  moveable  round 
a  pin  passing  through  its  centre. 

Puilies  are  of  two  kinds: — 1.  Fixed, 
which  do  not  move  out  of  their  places  ; 
2.  Moveable,  which  rise  and  fall  with  the 
weight. 

When  a  pulley  is  fixed,  as  Fig.  5,  Plate 
II.  two  equal  weights  suspended  to  the 
ends  of  a  rope  passing  over  it,  will  ba- 
lance each  other,  for  they  stretch  the  rope 
equally,  and  if  either  of  them  be  pulled 
down  through  any  given  space,  the  other 
will  rise  through  an  e  qual  space  in  the 
same  time ;  and  consequently,  as  the  ve- 
locities of  both  are  equal,  they  must  ba- 
lance each  other.  This  kind  of  pulley, 
therefore,  gives  no  mechanical  advantage ; 
so  that  you  can  raise  no  greater  weight 
by  it  than  you  could  do  by  your  natural 
strength.  Its  use  consists  in  changing  the 
direction  of  the  power,  and  sometimes 
enabling  it  to  be  applied  with  more  con- 
venience. By  it,  a  man  may  raise  a  weight 
to  any  point,  without  moving  from  the 
place  he  is  in  ;  whereas,  otherwise,  he 
would  have  been  obliged  to  ascend  with 
the  weight :  it  also  enables  several  men 
together  to  apply  their  strength  to  the 
weight  by  means  of  the  rope. 

The  moveable  pulley  represented  at  A 
(Fig.  6,  Plate  II.),  is  fixed  to  the  weight 
W,  and  rises  and  falls  with  it.  In  com- 
paring this  to  a  lever,  the  fulcrum  must 
be  considered  as  at  A  (Fig  6)  ;  the  weight 
acts  upon  the  centre  c,  and  the  power  is 
applied  at  the  extremity  of  the  lever  D. 
The  power,  therefore,  being  twice  as  far 
from  the  fulcrum  as  the  weight  is,  the 
proportion  between  the  power  and  weight, 
in  order  to  balance  each  other,  must  be  as 
1  to  2.  Whence  it  appears,  that  the  use 
of  this  pulley  doubles  the  power,  and  that 
a  man  may  raise  twice  as  much  by  it  as 
by  his  strength  alone.  Or  it  may  be  con- 
sidered in  this  way — Every  moveable  pul- 
ley hangs  by  two  ropes  equally  stretched, 
and  which  must,  consequently,  bear  equal 


parts  of  the  weight ;  but  the  rope  AB  be- 
I  ing  made  fast  at  B,  half  the  weight  is  sus- 
i  tamed  by  it,  and  the  other  part  of  the 
|  rope,  to  which  the  power  is  applied,  has 
but  half  the  weight  to  support ;  conse- 
quently the  advantage  gained  by  this  pul- 
ley is  as  2  to  1 

When  the  upper  and  fixed  block  con- 
tains two  puilies  which  only  turn  upon 
their  axis,  and  the  lower  moveable  block 
contains  also  two,  which  not  only  turn  on 
their  axis,  but  rise  with  the  weight  F 
(Fig.  7,  Plate  II.),  the  advantage  gained 
is  as  4  to  1.  For  each  lower  pulley  will 
be  acted  upon  by  an  equal  part  of  the 
weight ;  and  because  in  each  pulley  that 
moves  with  the  weight,  a  double  increase 
of  power  is  gained,  the  force  by  which  F 
may  be  sustained,  will  be  equal  to  half 
the  Weight  divided  by  the  number  of  low- 
er puilies ;  that  is,  as  twice  the  number  of 
lower  puilies  is  to  1,  so  is  the  weight  sus- 
pended to  the  power. 

But  if  the  extremity  C  (Fig.  8,  Plate 
II.)  be  fixed  to  the  lower  block,  it  will  sus- 
tain half  as  much  as  a  pulley ;  conse- 
quently here  the  rule  will  be,  as  twice  the 
number  of  puilies  adding  unity  is  to  1,  so 
is  the  weight  to  the  power. 

These  rules  hold  good,  whatever  may 
be  the  number  of  puilies  in  the  blocks. 

If,  instead  ol  one  rope  going  round  all 
the  puilies,  the  rope  belonging  to  each 
pulley  be  made  fast  at  top,  as  in  Fig.  9, 
Plate  II.  a  different  proportion  between 
the  power  and  the  weight  will  take  place. 
Here  it  is  evident,  that  each  pulley  dou- 
bles the  power :  thus,  if  there  are  two 
puilies,  the  power  will  sustain  four  times 
the  weight ;  if  three  puilies,  eight  times 
the  weight;  if  four  puilies,  sixteen  times  ; 
and  so  on 

When  puilies  in  blocks  are  placed  per- 
pendicularly under  each  other,  on  sepa- 
rate pins,  they  occupy  considerable  space, 
and  would  not  in  general  answer;  it  is, 
therefore,  common  to  place  all  the  puilies 
in  each  block  on  the  same  pin,  b}  the  side 
of  each  other,  as  in  Fig  10,  Plate  II. ;  but 
the  advantage,  and  rule  for  the  power,  are 
the  same  here  as  in  Fig.  7  and  8. 

A  pair  of  blocks  with  the  rope  fastened 
round  it,  is  commonly  called  a  tackle. 

The  Inclined  Plane. — This  mechanical 
power  is  of  very  great  use  in  rolling  up 
heavy  bodies,  such  as  casks,  wheel-bar- 
rows, &c  It  is  formed  by  placing  boards, 
or  earth,  in  a  sloping  direction. 

The  force  wherewith  a  body  descends 
upon  an  inclined  plane,  is  to  the  force  of 
its  absolute  gravity,  by  which  it  would 
descend  perpendicularly  in  free  space,  as, 
the  height  of  the  plane  is  to  its  length. 
For  suppose  the  plane  AB  (Fig.  1,  Plate 


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I.)  to  be  parallel  to  the  horizon,  the  cylin- 
der C  will  keep  at  rest  on  any  part  of  the 
plane  where  it  is  laid.  If  the  plane  be 
placed  perpendicularly,  as  AB,  Fig  2, 
the  cylinder  C  will  descend  with  its  whole 
force  of  gravity,  because  the  plane  con- 
tributes nothing  to  its  support  or  hin- 
drance ;  and  therefore  it  would  require  a 
power  equal  to  its  whole  weight  to  keep  it 
from  descending. 

Let  AB  (Fig  3)  be  a  plane  parallel  to 
the  horizon,  and  AD  a  plane  inclined  to 
it ;  and  suppose  the  whole  length  AD  to 
be  three  times  as  great  as  the  perpendicu- 
lar DB.  In  this  case,  the  cylinder  E  will 
be  supported  upon  the  plane  DA,  and 
kept  from  rolling,  by  a  power  equal  to  a 
third  part  of  the  weight  of  the  cylinder ; 
therefore  a  weight  may  be  rolled  up  this 
inclined  plane,  by  a  third  part  of  the  pow- 
er which  would  be  sufficient  to  draw  it 
up  by  the  side  of  an  upright  wall. 

It  must  also  be  evident,  that  the  less  the 
angle  of  elevation,  or  the  gentler  the  as- 
cent is,  the  greater  will  be  the  weight 
which  a  given  power  can  draw  up ;  for 
the  steeper  the  inclined  plane  is,  the  less 
does  it  support  of  the  weight;  and  the 
greater  the  tendency  which  the  weight 
has  to  roll,  consequently  the  more  diffi- 
cult for  the  power  to  support  it :  the  ad- 
vantage gained  by  this  mechanical  pow- 
er, therefore,  is  as  great  as  its  length  ex- 
ceeds its  perpendicular  height. 

To  the  inclined  plane  may  be  reduced 
all  hatchets,  chisels,  and  other  edge-tools. 

The  Wedge — The  fifth  mechanical  pow- 
er or  machine  is  the  wedge,  which  may 
be  considered  as  two  equally  inclined 
planes,  joined  together  at  their  bases ; 
then  DC  (Fig.  4)  is  the  whole  thickness  of 
the  wedge  at  its  back  A  BCD,  where  the 
power  is  applied;  EF  is  the  depth  or 
height  of  the  wedge ;  BF  the  length  of 
one  of  its  sides ;  and  OF  is  its  sharp  edge, 
which  is  entered  into  the  wood  intended 
to  be  split,  by  the  force  of  a  hammer  or 
mallet  striking  perpendicularly  on  its 
back.  Thus,  AB  (Fig  5)  is  a  wedge 
driven  into  the  cleft  CED  of  the  wood 
FG. 

When  the  wood  does  not  cleave  at  any 
distance  before  the  wedge,  there  will  be 
an  equilibrium  between  the  power  impell- 
ing the  wedge  downward  and  the  resist- 
ance of  the  wood  acting  against  the  two 
sides  of  the  wedge,  when  the  power  is  to 
the  resistance  as  half  the  thickness  of  the 
wedge  at  its  back  is  to  the  length  of  either 
of  its  sides  ;  because  the  resistance)  then 
acts  perpendicular  to  the  sides  of  the 
wedge.  But  when  the  resistance  on  each 
side  acts  parallel  to  the  back,  the  power 
that  balances  the  resistances  on  both  sides 


will  be,  as  the  length  of  the  whole  back 
of  the  wedge  is  to  double  its  perpendicu- 
lar height. 

When  the  wood  cleaves  at  any  distance 
before  the  Wedge  (as  it  generally  does) 
the  power  impelling  the  wedge  will  not  be 
to  the  resistance  of  the  wood  as  the  length 
on  the  back  of  the  Wedge  is  to  the  length 
of  both  its  sides,  but  as  half  the  length  of 
the  back  is  to  the  length  of  cither  side  of 
the  cleft,  estimated  from  the  top  or  acting 
part  of  the  wedge.  For,  if  \ve  suppose 
the  wedge  to  be  lengthened  down  from 
the  top  CE,  to  the  bottom  of  the  cleft  at 
D,  the  same  proportion  will  hold. ;  name- 
ly, that  the  power  will  be  to  the  resistance 
as  half  the  length  of  the  back  of  the 
wedge  is  to  the  length  of  either  of  its 
sides  :  or,  which  amounts  to  the  same 
thing,  as  the  whole  length  of  the  back  is 
to  the  length  of  both  the  sides. 

The  wedge  is  a  very  great  mechanical 
power,  since  not  only  wood,  but  even 
rocks,  can  be  split  by  it ;  which  it  would 
be  impossible  to  effect  by  the  lever,  wheel, 
and  axle,  or  pulley ;  for  the  force  of  the 
blow,  or  stroke,  shakes  the  cohering  parts, 
and  thereby  makes  them  separate  more 
easily. 

The  Screw.— The  sixth  and  last  me- 
chanical power  is  the  screw  ;  which  can- 
not properly  be  called  a  simple  machine, 
because  it  is  never  used  without  the  ap- 
plication of  a  lever  or  winch  to  assist  in 
turning  it ;  and  then  it  becomes  a  com- 
pound engine  of  a  very  great  force,  either 
in  pressing  the  parts  of  bodies  closer  to- 
gether, or  in  raising  great  weights.  It 
may  be  conceived  to  be  made  by  cutting 
a  piece  of  paper,  ABC  (Fig  6)  into  the 
form  of  an  inclined  plane  or  half  wedge  ; 
and  then  wrapping  it  round  a  cylinder 
(Fig.  7),  the  edge  of  the  paper  AC  will 
form  a  spiral  line  round  the  cylinder,  which 
will  give  the  thread  of  the  screw.  It  be- 
ing evident  that  the  winch  must  turn  the 
cylinder  once  round,  before  the  weight  of 
resistance  can  be  moved  from  one  spiral 
winding  to  another,  as  from  d  to  c  :  there- 
fore, as  much  as  the  circumference  of  a 
circle  described  by  the  handle  of  the  winch 
is  greater  than  the  interval  or  distance  be- 
tween the  spirals,  so  much  is  the  force  of 
the  screw.  Thus,  supposing  the  distance 
of  the  spirals  to  be  half  an  inch,  and  the 
length  of  the  winch  twelve  inches,  the  cir- 
cle described  by  the  handle  of  the  winch 
where  the  power  acts,  will  be  76  inches 
nearly,  or  about  152  half  inches ;  and  con- 
sequently 152  times  as  great  as  the  dis- 
tance between  the  spirals  :  and  therefore 
a  power  at  the  handle,  whose  intensity  is 
equal  to  no  more  than  a  single  pound, 
will  balance  152  pounds  acting  against 


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MEC 


the  screw  ;  and  as  much  additional  force 
as  is  sufficient  to  overcome  the  friction, 
will  raise  the  152  pounds  ;  and  the  velo- 
city of  the  power  will  be  to  the  velocity  of 
the  weight,  as  152  to  1.  Hence  it  appears, 
that  the  longer  the  winch  is,  and  the 
nearer  the  spirals  are  to  one  another,  so 
much  the  greater  is  the  force  of  the 
screw. 

A  machine  for  shewing-  the  force  or 
power  of  the  screw  may  be  contrived  in 
the  following-  manner: — Let  the  wheel  C 
have  a  screw  Fig-.  8,  on  its  axis,  working 
in  the  teeth  of  the  wheel  \),  which  sup- 
pose to  be  48  in  number  It  is  plain,  that 
for  every  time  the  wheel  C  and  screw  are 
turned  round  by  the  winch  A,  the  wheel  D 
will  be  moved  one  tooth  by  the  screw  ; 
and  therefore,  in  48  revolutions  of  the 
winch,  the  wheel  D  will  be  turned  once 
round.  Then,  if  the  circumference  of  a 
circle,  described  by  the  handle  of  the 
winch  A,  be  equal  to  the  circumference  of 
a  groove  round  the  wheel  1),  the  velocity 
of  the  handle  will  be  48  times  as  great  as 
the  velocity  of  any  given  point  in  the 
groove.  Consequently,  if  a  line  G  goes 
round  the  groove,  and  has  a  weight  of  48 
pounds  hung  to  it,  a  power  equal  to  1 
pound  at  the  handle  will  balance  and  sup- 
port the  weight.  To  prove  this  by  expe- 
riment, let  the  circumferences  of  the 
grooves  of  the  wheels  C  and  D  be  equal  to 
one  another ;  and  then  if  a  weight  H,  of 
one  pound,  be  suspended  by  a  line  going 
round  the  groove  of  the  wheel  C,  it  will 
balance  a  weight  of  48  pounds  hanging 
by  the  line  G  ;  and  a  small  addition  to  the 
weight  H  will  cause  it  to  descend,  and  so 
raise  up  the  other  weight. 

If  a  line  G,  instead  of  going  round  the 
groove  of  the  wheel  D,  goes  round  its 
axle  I,  the  power  of  the  machine  will  be 
as  much  increased  as  the  circumference 
of  the  groove  exceeds  the  circumference 
of  the  axle  :  which  supposing  it  to  be  six 
times,  then  one  pound  at  II  will  balance 
six  times  48,  or  288  pounds,  hung  to  the 
line  on  the  axle  :  and  hence  the  power  or 
advantage  of  this  machine  will  be  as  288 
to  1.  That  is  to  say,  a  man,  who  by  his 
natural  strength  could  lift  an  hundred 
weight,  will  be  able  to  raise  288  cwts.  by 
this  engine.  If  a  system  of  pullies  were 
applied  to  the  cord  H,  the  power  would  be 
increased  to  an  amazing  degree. 

When  a  screw  acts  in  a  wheel  in  this 
manner,  it  is  called  an  endless  screw. 

When  it  is  not  employed  in  turning  a 
wheel,  it  consists  of  two  parts  :  the  first 
is  called  the  male,  or  outside  screw,  be- 
ing cut  in  such  a  manner,  as  to  have  a 
prominent  part  going  round  the  cylinder 
in  a  spiral  manner ;  which  prominent  part 


is  called  the  thread  of  the  screw  ;  the 
other  part,  which  is  called  the  female,  or 
inside  screw,  is  a  solid  body,  containing  a 
hollow  cylinder,  whose  concave  surface  is 
cut  in  the  same  manner  as  the  convex  sur- 
face of  the  male  screw,  so  that  the  pro- 
minent parts  of  the  one  may  fit  the  con- 
cave parts  of  the  other. 

A  very  considerable  degree  of  friction 
always  acts  against  the  power  in  a  screw  ; 
but  this  is  fully  compensated  by  other  ad- 
vantages ;  for  on  this  account  the  screw 
continues  to  sustain  a  weight,  even  after 
the  power  is  removed,  or  ceases  to  act, 
and  presses  upon  the  body  against  which 
it  is  driven.  Hence  the  screw  will  sustain 
very  great  weights,  insomuch,  that  se- 
veral screws,  properly  applied,  would 
support  a  large  building,  whilst  the  foun- 
dation was  mending,  or  renewed. 

Messrs.  Carr  and  Hancock  have  obtain- 
ed a  patent  for  an  improved  screw  cutter. 
We  have  seen  the  machine  in  operation,  and 
from  its  power  it  is  capable  of  cutting  an 
iron  screw  in  a  very  short  time.  The  ma- 
chine promises  to  be  of  general  utility. 

Dr.  Mease  observes,  that  Mr.  Voight, 
chief  coiner  in  the  mint  of  the  United 
States,  has  invented  an  engine  for  turn- 
ing screws  of  any  given  diameter,  and  of 
any  number  of  threads,  to  an  inch.  This 
invention  was  first  designed  for  cutting 
fusees  for  watches,  so  as  uniformly  to  ad- 
just them  to  the  length  of  the  main-spring, 
a  thinsr  hitherto  very  difficult  in  practice, 
and  without  which  it  is  impossible  a  watch 
can  keep  regular  time.  By  the  aid  of  this 
machine  a  person  of  common  mechanical 
abilities,  and  without  any  knowledge  of 
mathematics,  may  adjust  the  fusee  to  the 
spring  with  the  greatest  exactness,  or 
turn  metallic  cylinders  and  cones  of  any 
length  or  diameter,  to  a  mathematical 
certainty. 

We  shall  say  something  more  on  this 
subject  under  Mechanics. 

A  combination  of  the  mechanical  powers. 
—The  following  engine  is  very  powerful, 
on  account  of  its  having  the  addition  of 
four  pullies ;  and  in  it  we  may  look  upon 
all  the  mechanical  powers  as  combined  to- 
gether,  even  if  we  take  in  the  balance. 
For,  as  the  axle  D  of  the  bar  AB  enters 
its  middle  at  C,  No.  4,  it  is  plain,  that  if 
equal  weights  be  suspended  upon  any 
two  pins  equi-distant  from  the  axis  C, 
they  will  counterpoise  each  other.  It  be- 
comes a  lever  by  hanging  a  small  weight 
P  upon  the  pin  n,  and  a  weight  as  much 
heavier  upon  either  of  the  pins  b,  c,  d,  e,  or 
/,  as  is  in  proportion  to  the  pins  being  so 
much  nearer  the  axis.  The  wheel  and 
axle  FG  is  evident  ;  so  is  the  screw  E 
which  takes  in  the  inclined  plane,  and  with 


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it  the  half-wedge.  Purl;  of  a  cord  goes  f  and  then  it  is  tied  to  a  hook  at  m  in  the 
round  the  axle,  the  rest  under  the  lower  lower  or  moveable  block,  on  which  the 
pullies  K,  m,  over  the  upper  pullies  L,  n,  \  weight  W  hangs. 


In  this  machine,  if  the  wheel  F  have  30 
teeth,  it  will  be  turned  once  round  in  thir- 
ty revolutions  of  the  bar  AB,  which  is  fix- 
ed on  the  axis  D  of  the  screw  E  :  if  the 
length  of  the  bar  be  equal  to  twice  the 
diameter  of  the  wheel,  the  pins  a  and  n 
at  the  ends  of  the  bar  will  move  60  times 
as  fast  as  the  teeth  of  the  wheel  do ;  and 
consequently,  one  ounce  at  P  will  balance 
60  ounces  hung  upon  a  tooth  at  q  in  the 
horizontal  diameter  of  the  wheel.  Then, 
if  the  diameter  of  the  wheel  F  be  ten 
times  as  great  as  the  diameter  of  the  axle 
G,  the  wheel  will  have  ten  times  the  velo- 
city of  the  axle  ;  and  therefore  one  ounce 
P  at  the  end  of  the  lever  AC,  will  balance 
10  times  60,  or  600  ounces  hung  to  the 
VOL.  II. 


rope  H  which  goes  round  the  axle.  Lastly, 
if  four  pullies  be  added,  they  will  make 
the  velocity  of  the  lower  block  K,  and 
weight  W,  four  times  less  than  the  velo- 
city of  the  axle  :  and  this  being  the  last 
power  in  the  machine,  which  is  four  times 
as  great  as  that  gained  by  the  axle,  it 
makes  the  whole  power  of  the  muchine  4 
times  600,  or  2400.  So  that  a  man  who 
could  lift  one  hundred  weight  in  his  arms 
by  his  natural  strength,  would  be  able  to 
raise  2400  times  as  much  by  this  engine. 
But  it  is  here  as  in  all  other  mechanical 
cases,  that  the  time  lost  is  always  as  much 
as  the  power  gained,  because  the  velocity 
with  which  the  power  moves  will  ever  ex- 
ceed the  velocity  with  which  the  weigh! 
I 


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n»es,  in  proportion  as  the  intensity  of  the 
weight  exceeds  the  intensity  of  the  power. 

The  friction  of  the  screw  itself  is  very 
considerable  ;  and  there  are  few  com- 
pound engines  but  what,  upon  account  of 
the  friction  of  the,parts  against  one  ano- 
ther, will  require  a  third  part  more  of 
power  to  work  them  when  loaded,  than 
whut  is  sufficient  to  constitute  a  balance 
between  the  weight  and  the  power. 

MECHANICS. — The  following  is  the 
substance  of  a  lecture  on  mills,  cranes, 
and  wheel-carriages,  from  Ferguson's 
Lectures. 

Mill-work. — As  these  engines  are  so 
univt  sally  useful,  it  would  be  needless 
to  make  any  apology  for  describing  them. 

Of  various  kinds  of  mills. — In  a  common 
breast-mill,*  where  the  fall  of  water  mav 
be  about  ten  feet,  AA  (Plate  III.  Fig.  2.) 
is  the  great  wheel,  which  is  generally 
about  IT  or  18  feet  in  diameter,  reckoned 
from  the  outermost  edge  of  any  float  - 
board  at  a  to  that  of  its  opposite  float  at 
b.  To  this  wheel  the  water  is  conveyed 
through  a  channel,  and,  by  falling  upon 
the  wheel,  turns  it  round 

On  the  axis  BB  of  this  wheel,  and  with- 
in the  mill-house,  is  a  wheel  D,  about  8 
or  9  feet  diameter,  having  61  cogs,  which 
turn  a  trundle  E,  containing  ten  upright 
staves  or  rounds;  and  when  these  are  the 
number  of  cogs  and  rounds,  the  trundle 
will  make  6-™  revolutions  for  one  revo- 
lution of  the  wheel. 

The  trundle  is  fixed  upon  a  strong  iron 
axis  culled  the  spindle,  the  lower  end  of 
which  turns  in  a  brass  foot,  fixed  at  F,  in 
the  horizontal  beam  ST  called  the  bridge- 
tree;  and  the  upper  part  of  the  spindle 
turns  in  a  wooden  bush  fixed  into  the  ne- 
ther millstone  which  lies  upon  beams  in 
the  floor  YY  The  top  part  of  the  spindle 
above  the  bush  is  square,  and  goes  into 


a  square  hole  in  a  strong  iron  cross  abed 
(see  Fig.  3.)  called  the  rynd ;  under  which, 
and  close  to  the  bush,  is  a  round  piece  of 
thick  leather  upon  the  spindle,  which  it 
turns  round  at  the  same  time  as  it  does 
the  rynd. 

The  rynd  is  let  into  grooves  in  the  un- 
der surface  of  the  running  millstone  G, 
(Fig.  2.)  and  so  turns  it  round  in  the  same 
time  that  the  trundle  E  is  turned  round  by 
the  cog-wheel  D.-\  This  millstone  has  a 
large  hole  quite  through  its  middle,  called 
the  eye  of  the  stone,  through  which  the 
middle  part  of  the  rynd  and  upper  end  of 
the  spindle  may  be  seen,  while  the  four 
ends  of  the  rynd  he  hid  below  the  stone 
in  their  grooves. 

The  end  T  of  a  bridge-tree  TS  (which 
supports  the  upper  millstone  G  upon  the 
spindle)  is  fixed  into  a  hole  in  the  wall ; 
and  t  e  end  iS'is  let  into  a  beam  QR  called 
the  brayer,  whose  end  R  remains  fixed 
in  a  mortise;  and  its  other  end  Q  hangs 
by  a  strong  iron  rod  P,  which  goes  through 
the  floor  YY,  and  has  a  screw-nut  on  its 
top  at  O ;  by  the  i  urning  of  which  nut, 
the  end  Q  of  the  brayer  is  raised  or  de- 
pressed at  pleasure  ;  and,  consequently, 
the  bridge-tree  TS  and  upper  millstone. 
By  this  means,  the  upper  millstone  may 
be,  set  as  close  to  the  under  one,  or  raised 
as  high  from  it,  as  the  miller  pleases.  The 
nearer  the  millstones  are  to  one  another, 
the  finer  they  grind  the  corn,  and  the 
more  remote  from  one  another,  the 
coarser. 

The  upper  millstone  G  is  inclosed  in  a 
round  box  H,  which  does  not  touch  it -any 
where  ;  and  is  about  an  inch  distant  from 
its  edge  all  around.  On  the  top  of  this 
box  stands  a  frame  for  holding  the  hopper 
kk,  to  which  is  hung  the  shoe  /  by  two 
lines  fastened  to  the  hind-part  of  it,  fixed 
upon  hooks  in  the  hopper,  and  by  one  end 


*  Water  mills  are  divided  into  breast-mills,  undershot-mills,  and  overs  hot -?ni  lis.  In 
breast-mills,  the  water  falls  at  right  angles  upon  the  float-boards  or  buckets,  placed 
upon  the  circumference  of  the  wheel  W  hen  float-boards  are  used  ,  the  water  acts 
by  its  impulse ;  but,  when  buckets  are  employed,  bothj-he  weight  and  impulse  of 
the  water  are  concerned  in  turning  the  wheel.  In  undershot-mills,  float-boards 
only  are  employed;  and  the  motion  of  the  wheel  affected  merely  by  the  force  of 
the  stream,  which  strikes  the  boards  below  the  wheel's  centre.  In  overshot-mills, 
buckets  only  are  used,  and  the  wheel  is  turned  chiefly  by  the  weight  of  the  water 
which  is  poured  over  its  top  into  the  buckets.  An  undershot-mill  requires  the  great- 
est quantity  of  water ;  and  an  overshot-mill  the  least.  It  has  long  been  disputed 
among  mechanical  philosophers,  whether  overshot  or  undershot-mills  produce  the 
greatest  effect.  M.  Beiidor  (Architecture  Ilydraulique)  maintained,  that  undershot- 
mills  were  greatly  superior  to  the  other  kind;  while  Dr  Desaguliers  held  a  contra- 
ry opinion.  It  appears,  however,  from  the  accurate  experiments  of  Mr.  Smeaton, 
that  in  undershot-mills  the  power  is  to  the  effect  as  3  to  1,  and  in  overshot-mills  as 
3  to  2,  or  rather  as  5  to  4. 

•J-  A  considerable  quantity  of  friction  might  be  removed  by  making  the  staves  or 
rounds  of  the  trundle  Ey  move  on  spindles  of  iron  or  brass,  fixed  to  the  end-boards. 


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of  the  crook-string  A"  fastened  to  the  fore 
part  of  it  at  i ;  the  other  end  being-  twisted 
round  the  pin  L.  As  the  pin  is  turned 
one  way,  the  string  draws  up  the  shoe 
closer  to  the  hopper,  and  so  lessens  the 
aperture  between  them  ;  and  as  the  pin  is 
turned  the  other  way,  it  lets  down  the 
shoe,  and  enlarges  the  aperture. 

If  the  shoe  be  drawn  up  quite  to  the 
hopper,  op  corn  can  fall  from  the  hopper 
into  the  mill;  if  it  be  let  a  little  down, 
some  will  fail;  and  the  quantity  will  be 
more  or  less,  according  as  the  shoe  is 
more  or  less  let  down.  For  the  hopper  is 
open  at  bottom,  and  there  is  a  hole  in  the 
bottom  of  the  shoe,  not  directly  under  the 
bottom  of  the  hopper,  but  forwarder  to- 
ward the  end  i,  over  the  middle  of  the  eye 
of  the  millstone. 

There  is  a  square  hole  in  the  top  of  the 
spindle,  in  which  is  put  the  feeder  e  ;  (Fig. 
3.)  this  feeder  (as  the  spindle  turns  round) 
jogs  the  shoe  three  times  in  each  revolu- 
tion, and  so  causes  the  corn  to  run  con- 
stantly down  from  the  hopper  through  the 
shoe,  into  the  eye  of  the  millstone,  where 
it  falls  upon  the  top  of  the  rynd,  and  is, 
by  the  motion  of  the  rynd,  and  the  leather 
under  it,  thrown  below  the  upper  stone, 
and  ground  between  it  and  the  lower  one. 
The  violent  motion  of  the  stone  creates  a 
centrifugal  force  in  the  corn  going  round 
with  it,  by  which  means  it  gets  farther  and 
farther  from  the  centre,  as  in  a  spiral,  in 
every  revolution,  until  it  be  thrown  quite 
off";  and  being  then  ground,  it  falls 
through  a  spout  M,  called  the  mill-eye, 
into  the  trough  JY 

When  the  mill  is  fed  too  fast,  the  corn 
bears  up  the  stone,  and  is  ground  too 
coarse  ;  and  besides,  it  clogs  the  mill  so 
as  to  make  it  go  too  slow.  When  the  mill 
is  too  slowly  fed,  it  goes  too  fast,  and  the 
stones  by  their  attrition  against  one  ano- 
ther, are  apt  to  strike  fire.  Roth  which 
inconveniences  are  avoided  by  turning 
the  pin  L  backward  or  forward,  which 
draws  or  lets  down  the  shoe ;  and  so  re- 
gulates the  feeding  as  the  miller  sees  con- 
venient. 

The  heavier  the  running  millstone  is,  and 
the  greater  the  quantity  of  water  that  falls 
upon  the  wheel,  so  much  the  faster  will 
the  mill  bear  to  be  fed  ;  and  conse  quently 
so  much  the  more  it  will  grind :  and,  on 
the  contrary,  the  lighter  the  stone,  and 
the  less  the  quantity  of  water,  so  much 
slower  must  the  feeding  be.    But  when 
the  stone  is  considerably  worn,  and  be- 
come light,  the  mill  must  be  fed  slowly  J 
at  any  rate;  otherwise  the  stone  will  be  I 
too  much  borne  up  by  the  corn  under  it,  ! 
which  will  make  the  meal  coarse. 

The  quantity  of  power  required  to  turn 


a  heavy  millstone  is  but  very  little  more 
than  what  is  sufficient  to  turn  a  light  one  : 
for  as  it  is  supported  upon  the  spindle 
by  the  bridgetree  8Tt  and  the  end  of 
the  spindle  that  turns  in  the  brass  foot 
therein  being  but  small,  the  odds  ari- 
sing from  the  weight  is  but  very  inconsi- 
derable in  its  action  against  the  power  or 
force  of  the  water  :  and,  besides,  a  heavy 
stone  has  the  same  advantage  as  a  heavy 
fly ;  namely,  that  it  regulates  the  motion 
much  be'^er  than  a  light  one. 

In  order  to  cut  and  grind  the  corn,  both 
the  upper  and  under  millstones  have  chan- 
nels or  furrows  cut  into  them,  proceeding 
obliquely  from  the  centre  toward  the  cir- 
cumference :  and  these  furrows  are  cut 
perpendicularly  on  one  side,  and  oblique- 
ly on  the  other  into  the  stone,  which  gives 
each  furrow  a  sharp  edge,  and  in*  the  two 
stones  they  come,  as  it  were,  against  one 
another,  like  the  edges  of  a  pair  of  scissors; 
and  so  cut  the  corn,  to  make  it  grind  the 
easier  when  it  falls  upon  the  places  be- 
tween the  furrows.  These  are  cut  the 
same  way  in  both  stones  when  they  lie 
upon  their  backs,  which  makes  them  run 
crosswise  to  each  other  when  the  upper 
stone  is  inverted  by  turning  its  furrowed 
surface  toward  that  of  the  lower.  For,  if 
the  furrows  of  both  stones  lay  the  same 
way,  a  great  deal  of  the  corn  would  be 
driven  onward  in  the  lower  furrows,  and 
so  come  out  from  between  the  stones  with- 
out being  either  cut  or  bruised. 

When  the  furrows  become  blunt  and 
shallow  by  wearing,  the  running  stone 
must  be  taken  up,  and  both  stones  new 
dressed  with  a  chisel  and  hammer ;  and 
every  time  the  stone  is  taken  up,  there 
must  be  some  tallow  put  round  the  spin- 
dle upon  the  bush,  which  will  soon  be 
melted  by  the  heat*  the  spindle  acquires 
from  its  turning  and  rubbing  against  the 
bush,  and  so  will  get  in  between  them, 
otherwise  the  bush  would  take  fire  in  a 
very  little  time. 

The  bush  must  embrace  the  spindle 
quite  close,  to  prevent  any  shake  in  the 
motion,  which  would  make  some  parts  of 
the  stones  grate  and  fire  against  each 
other,  while  other  parts  of  them  would  be 
too  far  asunder,  and  by  that  means  spoil 
the  meal  in  grinding. 

Whenever  the  spindle  wears  the  bush 
so  as  to  begin  to  shake  in  it,  the  stone 
must  be  taken  up,  and  a  chisel  driven  in- 
to several  parts  of  the  bush;  and  when  it 
is  taken  out,  wooden  wedges  must  be 
driven  into  the  holes  :  by  which  means  the 
bush  will  be  made  to  embrace  the  spindle 
close  all  around  it  again.  In  doing  this, 
great  care  must  be  taken  to  drive  equal 
wedges  into  the  bush  on  opposite  sides  of 


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the  spindle,  otherwise  it  will  be  thrown 
out  of  the  perpendicular,  and  so  hinder 
the  upper  stone  from  being  set  parallel  to 
the  under  one,  which  is  absolutely  neces- 
sary for  making-  good  work.  When  any 
accident  of  this  kind  happens,  the  perpen- 
dicular position  of  the  spindle  must  be 
restored  by  adjusting  the  bridge -tree  ST 
by  proper  wedges  put  between  it  and  the 
brayer  QR. 

It  often  happens  that  the  rynd  is  a  little 
wrenched  in  laying  down  the  upper  stone 
upon  it,  or  is  made  to  sink  a  little  lower 
upon  one  side  of  the  spindle  than  on  the 
other  ;  and  this  will  cause  one  edge  of  the 
upper  stone  to  drag  all  around  upon  the 
other,  while  the  opposite  edge  will  not 
touch.  But  this  is  easily  set  to  rights,  by 
raising  the  stone  a  little  with  a  lever,  and 
putting  kits  of  paper,  cards,  or  thin  chips 
between  the  rynd  and  the  stone. 

The  diameter  of  the  upper  stone  is  ge- 
nerally about  six  feet,  the  lower  stone 
about  an  inch  more ;  and  the  upper  stone, 
when  new,  contains  about  22h  cubic  feet, 
which  weighs  somewhat  more  than  1,900 
pounds.  A  stone  of  this  diameter  ought 
never  to  go  more  than  60  times  round  in  a 
minute  ;  for,  if  it  turn  faster,  it  will  heat 
the  meal. 

The  grinding  surface  of  the  under  stone 
is  a  little  convex  from  the  edge  to  the 
centre,  and  that  of  the  upper  stone  a  lit- 
tle more  concave :  so  that  they  are  far- 
thest from  one  another  in  the  middle,  and 
come  gradually  nearer  toward  the  edges. 
By  this  means,  the  corn  at  its  first  en- 
trance between  the  stones  is  only  bruised ; 
but  as  it  goes  farther  on  toward  the  cir- 
cumference or  edge,  it  is  cut  smaller  and 
smaller;  and  at  last  finely  ground  just 
before  it  comes  out  from  between  them. 

The  water-wheel  must  not  be  too  large  ; 
for,  if  it  be,  its  motion  will  be  too  slow ; 
nor  too  little,  for  then  it  will  want  power. 
And  for  a  mill  to  be  in  perfection,  the 
floats  of  the  wheel  ought  to  move  with 
a  third  part  of  the  velocity  of  the  water, 
and  the  stone  to  turn  round  once  in  a  se- 
cond of  time. 

In  order  to  construct  a  mill  in  this  per- 
fect manner,  observe  the  following  rules  : 

1.  Measure  the  perpendicular  height  of 
the  fall  of  water,  in  feet,  above  that  part 
of  the  wheel  on  which  the  water  begins 


to  act;  and  call  that  the  height  of  the 
fall. 

2.  Multiply  this  constant  number 
64,2882  by  the  height  of  the  fall  in  feet, 
and  the  square  root  of  the  product  will  be 
the  velocity  of  the  water  at  the  bottom  of 
the  fall,  or  the  number  of  feet  that  the  wa- 
ter there  moves  per  second. 

3.  Divide  the  velocity  of  the  water  by 
3,  and  the  quotient  will  be  the  velocity  of 
the  float -boards  of  the  wheel,  or  the  num- 
ber of  feet  they  must  each  go  through  in 
a  second,  when  the  water  acts  upon  them, 
so  as  to  have  the  greatest  power  to  turn 
the  mill. 

4.  Divide  the  circumference  of  the 
wheel  in  feet,  by  the  velocity  of  its  floats 
in  feet  per  second,  and  the  quotient  will 
be  the  number  of  seconds  in  which  the 
wheel  turns  round. 

5  By  this  last  number  of  seconds  di- 
vide 60  ;  and  the  quotient  will  be  the  num- 
ber of  turns  of  the  wheel  in  a  minute. 

6.  Divide  60  (the  number  of  revolutions 
the  millstone  ought  to  have  in  a  minute) 
by  the  number  of  turns  of  the  wheel  in 
a  minute,  and  the  quotient  will  be  the 
number  of  turns  the  millstone  ought  to 
have  for  one  turn  of  the  wheel. 

7.  Then,  as  the  number  of  turns  of  the 
wheel  in  a  minute  is  to  the  number  of 
turns  of  the  millstone  in  a  minute,  so  must 
the  number  of  staves  in  the  trundle  be  to 
the  number  of  cogs  in  the  wheel,  in  the 
nearest  whole  numbers  that  can  be  found. 

By  these  rules  has  been  calculated  the 
following  table  to  the- water-wheel  18  feet 
diameter,  which  it  is  apprehended  may  be 
a  good  size  in  general. 

To  construct  a  mill  by  this  table,  find 
the  height  of  the  fall  of  water  in  the  first 
column,  and  against  that  height,  in  the 
sixth  column,  you  have  a  number  of  cogs 
in  the  wheel,  and  staves  in  the  trundle, 
for  causing  the  millstone  to  make  about 
60  revolutions  in  a  minute,  as  near  as  pos- 
sible, when  the  wheel  goes  with  a  third 
part  of  the  velocity  of  the  water  :  and  it 
appears  by  the  seventh  column,  that  the 
number  of  cogs  in  the  wheel,  and  staves 
in  the  trundle,  are  so  near  the  truth  for 
the  required  purpose,  that  the  least  num- 
ber of  revolutions  of  the  millstone  in  a 
minute  is  between  59  and  60,  and  the 
greatest  number  never  amounts  to  61. 


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THE  MILL-WRIGHT'S  TABLE. 


Height 

Velocity  of 

Velocity  of 

Revolutions 

Revolutions 

Cogs  in  the 

Rev  of  the 

of  the 

the  water 

the  whee) 

of  the  wheel 

of  the  mill- 

wheel and 

mi  I! -stone  per 

fall  of 

oer  second 

per  second. 

per  minute. 

stone  lor  one 

staves 

in  the 

coin,  by  these 

water. 

of  the  wheel. 

trundle 

staves  &.  cogs. 

i— • 

t— * 

Feet. 

)0  parts 
a  foot. 

Feet. 

)0  parts 
a  foot. 

Feet. 

)0  parts 
a  rev. 

Rev. 

)0  parts 
a  rev. 

Rev. 

Q 

& 

Staves. 

'0  parts 
a  rev. 

Rev. 

o 

o 

o 

o 

o 

**» 

1 

8.02 

2.67 

2.83 

21.20 

127 

6 

59.92 

o 

11.34 

3.78 

4.00 

15.00 

105 

7 

60.00 

*> 

13.89 

4.63 

4.91 

12.22 

98 

8 

60.14 

4 

16.04 

5.35 

5.67 

10.58 

95 

9 

59.87 

5 

l  7.9o 

5.98 

<3  A 

O  A  & 

85 

9 

6 

19.64 

6.55 

6.94 

8.64 

m 

9 

60.10 

7 

21.21 

7.07 

7.50 

8.00 

72 

9 

60.00 

8 

22.68 

7.56 

8.02 

7.48 

67 

9 

59.67 

9 

24.05 

8.02 

8.51 

7.05 

70 

10 

59.57 

10 

25.35 

8.45 

8.97 

6.69 

67 

10 

60.09 

11 

26.59 

8.86 

9.40 

6.38 

64 

10 

60.16 

12 

27.77 

9.26 

9.82 

6.1 1 

61 

10 

59.90 

1 3 

28.91 

9.64 

10.22 

5.87 

59 

10 

60.18 

14 

30.00 

10.00 

10.60 

5.66 

56 

10 

59.36 

15 

31.05 

10.35 

10.99 

5.46 

55 

10 

60.48 

16 

32.07 

10.69 

11.34 

5.29 

53 

10 

60.10 

17 

33.06 

1 1.02 

11.70 

5.13 

51 

10 

59.67 

18 

34.02 

1  1.34 

12.02 

4.99 

50 

10 

60.10 

19 

34.95 

11.65 

12.37 

4.85 

49 

10 

60.61 

20 

35.86 

11.95 

12.68 

4.73 

47 

10 

59.59 

1 

2 

3 

4 

5 

6 

7 

Such  a  mill  as  this,  with  a  fall  of  water 
about  7^  feet,  will  require  about  32  hogs- 
heads every  minute  to  turn  the  wheel 
with  a  third  part  of  the  velocity  with 
which  the  water  falls  ;  and  to  overcome 
the  resistance  arising  from  the  friction  of 
the  gears,  and  attrition  of  the  stones  in 
grinding  the  corn. 

The  greater  fall  the  water  has,  the  less 
quantity  of  it  will  serve  to  turn  the  mill. 
The  water  is  kept  up  in  the  mill-dam,  and 
let  out  by  a  sluice  called  the  penstock, 
when  the  mill  is  to  go.  When  the  pen- 
stock is  drawn  up  by  means  of  a  lever,  it 
opens  a  passage  through  which  the  water 
flows  to  the  wheel ;  and  when  the  mill  is 
to  be  stopt,  the  penstock  is  to  be  let 
down,  which  stops  the  water  from  falling 
upon  the  wheel. 


A  less  quantity  of  water  will  turn  «n 
over-shot  mill  (where  the  wheel  has  buck- 
ets instead  of  floatboards)  than  a  breast- 
mill,  where  the  fall  of  the  water  seldom 
exceeds  half  the  height  A  b  of  the  wheel : 
so  that,  where  there  is  but  a  small  quan- 
tity of  water,  and  a  fall  great  enough  for 
the  wheel  to  lie  under  it,  the  bucket  or 
overshot- wheel  is  always  used.  Butwhere 
there  is  a  large  body  of  water,  with  a  lit- 
tle fall,  the  breast  or  floatboard  wheel 
must  take  place.  Where  the  water  runs 
only  upon  a  little  declivity,  it  can  act  but 
slowly  upon  the  under  part  of  the  wheel 
at  b ;  in  which  case,  the  motion  of  the; 
wheel  will  be  very  slow,  and  therefore, 
the  floats  ought  to  be  very  long,  though 
not  high,  that  a  large  body  of  water  maj 
act  upon  them  ;  so  that  what  is  wanting 


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m  velocity  may  be  made  up  in  power ;  and ,  the  wheel  exactly ;  that  is  to  say,  the  trim* 
then  the  cog-wheel  may  have  a  greater  die  might  make  a  given  number  of revo- 
number  Of  cogs  in  proportion  to  the.lutions  for  one  of  the  wheel,  without  a 
rounds  in  the  trundle,  in  order  to  give  the  j fraction.  But  as  any  exact  number  is  not 
millstone  a  sufficient  degree  of  velocity.  J  necessary  in  mill-work,  and  the  cogs  and 
They  who  have  read  what  is  said;  rounds  cannot  be  set  in  so  truly  as  to 
concerning    the    acceleration    of    bo-  make   all  the  intervals  between  them 


dies  falling  freely  by  the  power  of  gra- 
vity acting  constantly  and  uniform- 
ly upon  them,  may  perhaps  ask,  Why 
should  the  motion  of  the  wheel  bcs'  equa- 
ble, and  not  accelerated,  seeing  the  water 
acts  constantly  and  uniformly  upon  it  ? 
The  plain  answer  is,  That  the  velocity  of 
the  wheel  can  never  be  so  great  as  the 
velocity  of  the  water  that  turns  it ;  for  if 
it  should  become  so  great,  the  power  of 
the  water  would  be  quite  lost  upon  the 
wheel,  and  then  there  would  be  no  pro- 
per force  to  overcome  the  friction  of  the 
gears  and  attrition  of  the  stones.  There- 
fore, the  velocity  with  which  the  wheel 
begins  to  move,  w«!i  increase  no  longer 
than  till  its  momentum  or  force  is  balan- 
ced by  the  resistance  of  the  working  parts 
of  the  mill :  and  then  the  wheel  will  go 
on  with  an  equable  motion.* 

If  the  cog-wheel  1)  be  made  about  18 
inches  diameter,  with  30  cogs,  the  trun- 
dle as  small  in  proportion,  with  10  staves, 
and  the  millstones  be  each  about  two  feet 
in  diameter,  and  the  whole  work  be  put 
into  a  strong  frame  of  wood,  as  represent- 
ed in  the  figure,  the  engine  will  be  a  hand- 
mill  for  grinding  com  or  malt  in  private 
families  :  and  then,  it  may  be  turned  by  a 
winch  instead  of  the  wheel  A  A;  the  mill- 
stone making  three  revolutions  for  every 
one  of  the  winch.  If  a  heavy  fly  be  put 
upon  the  axle  /?,  near  the  winch,  it  will 
help  to  regulate  the  motion,  j 

If  the  cogs  of  the  wheel  and  rounds  of 
the  trundle  could  be  put  in  as  exactly  as 
the  teeth  are  cut  in  the  wheels  and  pinions 
of  a  clock,  then  the  trundle  might  divide! 


equal,  a  skilful  mi  1-wright  will  always 
give  the  wheel  what  he  calls  a  hunting 
cog  ;  that  is,  one  more  than  what  will  an- 
swer to  an  exact  division  of  the  wheel  by 
the  trundle.  And  then,  as  every  cog  comes 
to  the  trundle,  it  will  take  the  next  staff 
or  round  behind  the  one  which  it  took  in 
the  former  revolution  ;  and  by  that  means 
will  wear  all  the  parts  of  the  cogs  and 
rounds  which  work  upon  one  another 
equally,  and  to  equal  distances  from  one 
another  in  a  iittle  time ;  and  so  make  a 
true  uniform  motion  throughout  the  whole 
work.  Thus,  in  the  above  water-mill,  the 
trundle  lias  10  staves,  and  the  wheel  61 
cogs. 

Somet'mes,  Amere  there  is  a  sufficient 
quantity  of  water,  the  cog-wheel  A  A,  Fig. 
4.  No.  1.  turns  a  large  trundle  B  B,  on 
whose  axis  C  is  fixed  the  horizontal  wheel 
J),  with  cogs  all  around  its  edge,  turning 
two  trundles  E  and  F  at  the  same  time  ; 
whose  axes  or  spindles  G  and  //turn  two 
mill-stones  /and  A"  upon  the  fixed  stones 
L  and  M  And  when  there  is  not  work 
for  them  both,  either  may  be  made  to  lie 
quiet,  by  taking  out  one  of  the  staves  in 
its  t: midle,  and  turning  the  vacant  place 
toward  the  cog-wheel  D :  also,  there  may 
be  a  wheel  fixed  on  the  upper  end  of  the 
great  upright  axle  C,  for  turning  a  couple 
of  boulting-mills,  and  other  work;  for 
drawing  up  the  sacks,  fanning  and  clean- 
ing the  corn,  sharpening  of  tools,  &c. 

If,  instead  of  the  cog-wheel  A  A,  and 
trundle  B  B,  horizontal  levers  be  fixed 
into  the  axle  C,  below  the  wheel  Z>,  then 
horses  may  be  put  to  these  levers  for 


*  The  author's  explanation  of  this  remarkable  fact,  viz.  that  the  best  constructed 
machines  acquire  in  a  short  time  a  uniform  motion,  is  far  from  being  satisfactory. — 
The  question  indeed,  is  extremely  difficult ;  and  from  our  imperfect  knowledge  of 
the  nature  of  friction,  it  does  not  admit  of  a  scientific  explanation.  When  a  pendu- 
lum-clock is  stripped  of  its  pallets,  and  allowed  to  run  down,  it  acquires  a  uniform 
motion  in  a  very  short  time,  though  there  is  little  friction,  and  though  the  moving 
power  acts  with  the  greatest  uniformity.  Dr.  Robison  observes,  that  the  "  uniform 
motion  of  machines  arises  from  a  diminution  of  the  impelling  power  by  an  increase  of 
velocity  ;  but  that  there  is  something  yet  unexplained  in  the  nature  of  friction,  which 
takes  away  some  of  the  acceleration."  ' 

-j-  If  the  fly  be  put  upon  the  axle  B,  its  velocity  will  not  be  sufficient  to  make  it  of 
any  use  as  a  regulator.  In  an  ingenious  hand-mill,  invented  by  Mr  Lloyd,  this  defect 
is  remedied  by  fixing  a  hollow  circular  fly  upon  the  upper  millstone,  with  iron  straps. 
Its  diameter  is  two  feet,  the  breadth  of  its  rim  three  inches  and  a  half,  and  its  depth 
five  inches.  It  is  divided  into  six  cavities,  into  which  a  quantity  of  lead  shot  is  put  to 
bring  it  to  a  proper  weight.  For  this  invention  Mr.  Lloyd  was  rewarded  with  fifty 
pounds.  A  drawing  and  description  of  it  may  be  seen  in  Bailey's  Designs  of  Ma- 
chines, approved  and  adopted  by  the  Society  of  Arts,  vol.  1,  p.  176 ;  and  vol.  2.  44. 


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turning  the  mill;  which  is  often  done 
where  water  cannot  be  had  for  that  pur- 
pose 

The  working  parts  of  a  wind-mill  differ 
very  little  from  those  of  a  water-mill; 
only  the  former  is  turned  by  the  action 
of  the  wind  upon  four  sails,  every  one  of 
which  ought  (as  is  generally  believed) 
to  make  an  angle  of  54^  degrees,  with  a 
plane  perpendicular  to  the  axis  on  which 
the  arms  are  fixed  for  carrying  them.  It 
being  demonstrable,  that  when  the  tails 
are  set  to  such  an  angle,  and  the  axis 
turned  endwise  toward  the  wind,  the 
wind  has  the  greatest  power  upon  the 
sails.  But  this  angle  answers  only  to  the 
case  of  a  vane  or  sail  just  beginning  to 
move :  [Note.  See  Maclaurin's  Fluxions, 
near  the  end  ]  for,  when  the  vane  has  a 
certain  degree  of  motion,  it  yields  to  the 
wind ;  and  then  that  angle  must  be  in- 
creased to  give  the  wi  ld  its  full  effect. 

Again,  the  increase  of  this  angle  should 
be  different,  according  to  the  different  ve- 
locities from  the  axis  to  the  extremity  of 
the  vane.  At  the  axis  it  should  be  54  J  de- 
grees, and  thence  continually  decrease, 
giving  the  vane  a  twist,  and  so  causing  all 
the  ribs  of  the  vane  to  lie  in  different 
planes. 

Lastly,  these  ribs  ought  to  decrease  in 
length  from  the  axis  to  the  extremity, 
giving  the  vane  a  curvilineal  form  ;  so 
that  no  part  of  the  force  of  any  one  rib  is 
spent  upon  the  rest,  but  all  move  on  in- 
dependent of  each  other.  All  this  is  re- 
quired to  give  the  sails  of  a  wind-mill 
their  true  form;  and  we  see  both  the 
twist  and  the  diminution  of  the  ribs  ex- 
emplified in  the  wings  of  birds. 

It  is  almost  incredible  to  think  with 
what  velocity  the  tips  of  the  sails  move 
when  acted  upon  by  a  moderate  gale  of 
wind.  I  have  several  times  counted  the 
number  of  revolutions  made  by  the  sails 
in  ten  or  fifteen  minutes ;  and'  from  the 
length  of  the  arms  from  tip  to  tip,  have 
computed,  that  if  a  hoop  of  that  diameter 
was  to  run  upon  the  ground  with  the  same 
velocity  it  would  have  if  put  upon  the  sail- 
arms,  it  would  go  upwards  of  30  miles  in 
an  hour. 

As  the  ends  of  the  sails  nearest  t  he  axis 
cannot  move  with  the  same  velocity  that 
the  tips  or  farthest  ends  do,  although  the 
wind  acts  equally  strong  upon  them,  per- 
haps a  better  position  than  that  of 
stretching  them  along  the  arms  directly 
upon  the  centre  of  motion,  might  be  to 
have  them  set  perpendicularly  across  the 
farther  ends  of  the  arms,  and  there  ad- 
justed lengthwise  to  the  proper  angle. 
For,  in  that  case,  both  ends  of  the  sails 


would  move  with  the  same  velocity ;  and 
being  farther  from  the  centre  of  motion, 
they  would  have  so  much  the  more  pow- 
er :  and  then  there  would  be  no  occasion 
for  having  them  so  large  :is  they  are  ge- 
nerally made ;  which  would  render  them 
lighter,  and  consequently  there  would  be 
so  much  the  less  friction  on  the  thick 
neck  of  the  axle  where  it  turns  in  the 
wall.  \_Note  A  description  of  an  improv- 
ed wind-mill,  and  an  account  of  Smeaton 
and  Couiomb's  improvements,  may  be 
seen  in  vol.  2d.  of  Ferguson's  lectures.] 

Of  the  Crane — A  crane  is  an  engine  by 
which  great  weights  are  raised  to  certain 
heights,  or  let  down  to  certain  depths.  It 
consists  of  wheels,  axles,  pulleys,  ropes, 
and  "a  gib  or  gibbet  When  the  rope  U, 
Fig.  1 ,  Plate  4,  is  hooked  to  the  weight  K9 
a  man  turns  the  winch  A,  on  the  axis 
whereof  is  the  trundle  B,  which  turns  the 
wheel  C,  on  whose  axis  D  is  the  trundle 
E,  which  turns  the  wheel  F  with  its  up- 
right axis  G,  on  which  the  great  rope  HH 
winds  as  the  wheelturns ;  and  going  over 
a  pulley  /  at  the  end  of  the  arm  d  of  the 
gib  ce  de,  it  draws  up  the  heavy  weight 
K\  which,  being  raised  to  a  proper 
height,  as  from  a  ship  to  the  quay,  is  then 
brought  over  the  quay  by  pulling  the 
wheel  Z  round  by  the  handles  z,z,  which 
turns  the  gib  by  means  of  the  half-wheel 
b  fixed  on  the  gib-post  cc,  and  the  strong 
pinion  a  fixed  on  the  axis  of  the  wheel  Z. 
This  wheel  gives  the  man  that  turns  it  an 
absolute  command  over  the  gib,  so  as  to 
prevent  it  from  taking  an  unlucky  swing, 
such  as  often  happens  when  it  is  only- 
guided  by  a  rope  tied  to  its  arm  d ;  and 
people  are  frequently  hurt,  sometimes 
killed,  by  such  accidents. 

The  great  rope  goes  between  two  up- 
right rollers  i  and  which  turn  upon 
gudgeons  in  the  fixed  beams /ittdgi  and 
as  the  gib  is  turned  toward  either  side,  the 
rope  bends  upon  the  roller  next  that  side. 
Were  it  not  for  these  rollers,  the  gib  would 
be  quite  unmanageable  ;  for  the  moment 
it  were  turned  ever  so  little  toward  any 
side,  the  weight  K  would  begin  to  de- 
scend, because  the  rope  would  be  short- 
ened between  the  pulley  /  and  axis  G ; 
and  so  the  gib  u;ould  be  pulled  violently 
to  that  side,  and  cither  be  broken  to  pie- 
ces, or  break  every  thing  that  came  in  its 
way.  These  rollers  must  be  so  placed, 
that  the  sides  of  them,  round  which  the 
rope  bends,  may  keep  the  middle  of  the 
bended  part  directly  even  with  the  centre 
of  the  hole  in  which  the  upper  gudgeon 
of  the  gib  turns  in  the  beamy!  The  truer 
"these  rollers  are  placed,  the  easier  the  gib 
is  managed,  and  the  less  apt  to  swing 


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cither  way  by  the  force  of  the  weight 

A  ratchet-wheel  Q  is  fixed  upon  the 
axis  D,  near  the  trundle  E ;  and  into  this 
wheel  the  catch  or  click  It  falls.  This 
hinders  the  machinery  from  running  back 
by  the  weight  of  the  burden  A,  if  the  man 
who  raises  it  should  happen  to  be  care- 
less, and  so  leave  off  working  at  the  winch 
A  sooner  than  he  ought  to  do. 

When  the  weight  K  is  raised  to  its 
proper  height  from  the  ship,  and  brought 
over  the  quay  by  turning  the  gib  about,  it 
is  let  down  gently  upon  the  quay,  or  into 
a  cart  standing  thereon,  in  the  following 
manner : — A  man  takes  hold  of  the  rope 
1 1  (which  goes  over  the  pulley  u,  and  is 
tied  to  a  hook  at  S  in  the  catch  R)  and  so 
disengages  the  catch  from  the  ratchet- 
wheel  Q ;  and  then  the  man  at  the  winch 
A  turns  it  backward,  and  lets  down  the 
weight  K.  But  when  the  weight  pulls  too 
hard  against  this  man,  another  lays  hold 
of  the  stick  F,  and  by  pulling  it  down- 
ward, draws  the  gripe  U  close  to  the 
wheel  T,  which,  by  rubbing  hard  against 
the  gripe,  hinders  the  too  quick  descent 
of  the  weight :  and  not  only  so,  but  even 
stops  it  any  time,  if  required.  By  this 
means,  heavy  goods  may  be  either  raised 
or  let  down  at  pleasure,  without  any  dan- 
ger of  hurting  the  men  who  work  the  en- 
gine. 

When  part  of  the  goods  is  craned  up, 
and  the  rope  is  to  be  let  down  for  more, 
the  catch  It  is  first  disengaged  from  the 
ratchet-wheel  Q,  by  pulling  the  cord£; 
then  the  handle  q  is  turned  half  round 
backward,  which  by  the  crank  n  n  in  the 
piece  o,  pulls  down  the  frame  h  between 
the  guides  m  and  m  (in  which  it  slides  in 
a  groove)  and  so  disengages-  the  trundle 
J?  from  the  wheel  C:  and  then  the  heavy 
hook  b  at  the  end  of  the  rope  //descends 
by  its  own  weight,  and  turns  back  the 
great  wheel  F  with  its  trundle  E,  and  the 
wheel  C ;  and  this  last  wheel  acts  like  a 
fly  against  the-  wheel  F  and  hook  b,  and 
so  hinders  it  from  going  down  too  quick; 
while  the  weight  X  keeps  up  the  gripe  U 
from  rubbing  against  the  wheel  T,  by 
means  of  a  cord  going  from  the  weight, 
over  the  pulley  «u  to  the  hook  W  in  the 
gripe ;  so  that  the  gripe  never  touches  the 
wheel,  unless  it  be  pulled  down  by  the 
handle  V. 

When  the  crane  is  to  be  set  at  work 
again,  for  drawing  up  another  burden, the 
handle  q  is  turned  half  round  forward  j 
which  by  the  crank  n  n,  raises  up  the 
frame  h,  and  causes  the  trundle  B  to  lay 
hold  of  the  wheel  C;  and  then,  by  turning 
the  winch  A,  the  burden  of  goods  K  is 
drawn  up  as  before. 


The  crank  n  n  turns  pretty  stiff  in  the 
mortice  near  0,  and  stops  against  the  far- 
ther end  of  it  when  it  has  goi  just  a  little 
beyond  the  perpendicular;  so  that  it  can 
never  come  back  of  itself :  and  therefore, 
the  trundle  B  can  never  come  away  from 
the  wheel  C,  until  the  handle  q  be  turned 
half  round  backward. 

The  great  rope  runs  upon  rollers  in  the 
lever  LM,  which  keeps  it  from  bending 
between  the  axle  at  G  and  the  pulley  /. 
This  lever  turns  upon  the  axis  N,  by 
means  of  the  weight  O,  which  is  just  suf- 
ficient to  keep  its  end  L  up  to  the  rope  ; 
so  that,  as  the  great  axle  turns,  and  the 
rope  coils  round  it,  the  lever  rises  with 
the  rope,  and  prevents  the  coilings  from 
going  over  one  another. 

The  power  of  this  crane  may  be  esti- 
mated thus  : — suppose  the  trundle  B  to 
have  13  staves  or  rounds,  and  the  wheel 
C  to  have  78  spurcogs  ;  the  trundle  E  to 
have  14  staves,  and  the  wheel  F  56  cogs. 
Then,  by  multiplying  the  staves  of  the 
trundles,  13  and  14,  into  one  another,  their 
product  will  be  182 :  and  by  multiplying 
the  cogs  of  the  wheels,  78  and  56,  into 
one  another,  their  product  will  be  4368, 
and  dividing  4368  by  182,  the  quotient 
will  be  24 ;  which  shows  that  the  winch 
A  makes  24  turns  for  one  turn  of  the 
wheel  F  and  its  axle  G,  on  which  the 
great  rope  or  chain  H I H winds.  So  that, 
if  the  length  or  radius  of  the  winch  A 
were  only  equal  to  half  the  diameter  of 
the  great  axle  G,  added  to  half  the  thick- 
ness of  the  rope  //,  the  power  of  the  crane 
would  be  as  24  to  1 ;  but  the  radius  of 
the  winch  being  double  the  above  length, 
it  doubles  the  said  power,  and  so  makes  it 
as  48  to  1 ;  in  which  case,  a  man  may 
raise  48  times  as  much  weight  by  this  en- 
gine as  he  could  do  by  his  natural  strength 
without  it,  making  proper  allowance  for 
the  friction  of  the  working  parts. — Two 
men  may  work  at  once,  by  having  another 
winch  on  the  opposite  end  of  the  axis  of 
the  trundle  under  B;  and  this  will  make 
the  power  double. 

If  this  power  be  thought  greater  than 
what  may  be  generally  wanted,  the  wheels 
may  be  made  with  fewer  cogs  in  propor- 
tion to  the  staves  in  the  trundles ;  and  so 
the  power  may  be  of  whatever  degree  is 
judged  to  be  requisite.  But  if  the  weight 
be  so  great  as  will  yet  require  more  pow- 
er to  raise  it,  suppose  a  double  quantity, 
then  the  rope  H  may  be  put  under  a 
moveable  pulley,  as  d,  and  the  end  of  it 
tied  to  a  hook  in  the  gib  at  m;  which  will 
give  a  double  power  to  the  machine,  and 
so  raise  a  double  weight  hooked  to  the 
block  Of  the  moveable  pulley. 

When  only  small  burdens  are  to  be  rais- 


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ed,  this  may  be  quickly  done  by  men 
pushing  the  axle  G  round  the  long  spokes 
/>  j,  y,  y ;  having-  first  disengaged  the 
trundle  B  from  the  wheel  C:  and  then, 
this  wheel  will  only  act  as  a  fly  upon  the 
wheel  Fi  and  the  catch  It  will  prevent 
its  running  back,  if  the  men  should  inad- 
vertently leave  off  pushing  betbre  the  bur- 
den be  unhooked  from  b. 

Lastly,  when  very  heavy  burdens  are  to 
be  raised,  which  might  endanger  the 
.  breaking  of  the  cogs  in  the  wheel  F ; 
their  force  against  these  cogs  may  be 
much  abated  by  men  pushing  round  the 
long  spokes  y,  y, y,  y,  while  the  man  at  A 
turns  the  winch. 

1  have  only  shown  the  working  parts  of 
this  crane,  without  the  whole  of  the  beams 
which  support  them;  knowing  that  these 
are  easily  supposed,  and  that  if  they  had 
been  drawn,  they  would  have  hid  a  great 
deal  of  the  working  parts  from  sight,  and 
also  confused  the  figure. 

Another  very  good  crane  is  made  in  the 
following  manner.— A  A  ( Plate  IV.  Fig.  2) 
is  a  great  wheel  turned  by  men  walking 
within  it  at  //  On  the  part  C,  of  its  axle 
BC,  the  great  rope  J)  is  wound  as  the  wheel 
turns ;  and  this  rope  draws  up  goods  in 
the  same  way  as  the  rope  H  h  does  in  the 
above-mentioned  crane,  the  gib-work  here 
b?ing  supposed  to  be  of  the  same  sort. 
But  these  cranes  are  very  dangerous  to 
the  men  in  the  wheel ;  for,  if  any  of  the 
men  should  chance  to  fall,  the  burden  will 
make  the  wheel  run  backhand  throw  them 
all  about  within  it ;  which  often  breaks 
their  limbs,  and  sometimes  kills  them, 
The  late  ingenious  Mr.  Padmore,  of  Bris- 
tol (whose  contrivance  the  fore-mention- 
ed crane  is)  observing  this  dangerous  con 
struction,  contrived  a  method  of  remedy- 
ing it,  by  putting  cogs  all  around  the  out- 
side of  the  wheel,  and  applying  a  trundle 
E  to  turn  it ;  which  increases  the  power 
as  much  as  the  number  of  cogs  in  the 
wheel  is  greater  than  the  number  of  staves 
in  the  trundle ;  and  by  putting  a  ratchet- 
wheel  F  on  the  axis  of  the  trundle  (as  in 
the  above-mentioned  crane)  with  a  catch 
to  fall  into  it,  the  great  wheel  is  stopt 
from  running  back  by  the  force  of  the 
weight,  even  if  all  the  men  in  it  should 
leave  off  walking  :  and  by  one  man  work- 
ing at  the  winch  1,  or  two  men  at  the  op- 
posite winches  when  needful,  the  men  in 


the  wheel  are  much  assisted,  and  much 
greater  weights  are  raised^han  rould  be 
done  by  men  only  wilhin  the  wheel.  Mr. 
Padmore  put  also  a  gripe-wheel  G  upon 
the  axis  of  the  trundle,  which  being- pinch- 
ed in  the  same  manner  as  described  in  the 
former  crane,  heavy  burdens  may  be  let 
down  without  the  least  danger.  And  be- 
fore this  contrivance,  the  lowering  of 
goods  was  always  attended  with  the  ut- 
most danger  to  the  men  in  the  wheel ;  as 
every  one  must  be  sensible  of,  who  has 
seen  such  engines  at  work. 

And  it  is  surprising  that  the  masters  c: 
wharves  and  cranes  should  be  so  regard- 
less of  the  limbs,  or  even  lives,  of  their 
workmen,  that,  excepting  the  late  Sir 
James  Creed,  of  Greenwich,  and  some 
gentlemen  at  Bristol,  there  is  scarce  an 
instance  of  any  one  who  has  used  this  safe 
contrivance.** 

A  description  "of  a  new  and  safe  Crane, 
which  has  four  different  powers,  adapted 
to  different  weights. — By  Mr.  Brewster. 

The  common  crane  consists  only  of  a 
large  wheel  and  axle  ;  and  the  rope,  by 
which  goods  are- drawn  up  from  ships,  or 
let  down  to  them  from  the  quay,  winds  or 
coils  round  the  axle,  as  the  axle  is  turned 
by  men  walking  in  the  wheel.  But,  as  these 
engines  have  nothing  to  stop  the  weight 
from  running  down,  if  any  of  the  men 
happen  to  trip  or  fall  in  the  wheel,  the 
weight  descends,  and  turning  the  wheel 
rapidly  backward,  tosses  the  men  violent- 
ly about  within  it ;  which  has  produced 
melancholy  instances,  not  only  of  limbs 
broken,  but  even  of  lives  lost,  by  this  ill- 
judged  construction  of  cranes.  And  be- 
sides, they  have  but  one  power  for  all 
sorts  of  weights ;  so  that  they  generally 
spend  as  much  time  in  raising  a  small 
weight  as  in  raising  a  great  one. 

These  imperfections  and  dangers  induc- 
ed me  to  think  of  a  method  for  remedy- 
ing them.  And  for  that  purpose,  I  con- 
trived a  crane  with  a  proper  stop  to  pre- 
vent the  danger,  and  with  different  pow- 
ers suited  to  different  weights ;  so  that 
there  might  be  as  little  loss  of  time  as 
possible :  and  also,  that  when  heavy  goods 
are  let  down  into  ships,  the  descent  may 
be  regular  and  deliberate. 

This  crane  has  four  different  powers  : 


*  An  improved  crane  for  wharves  has  lately  been  invented  by  Mr.  Robert  Hall,  of 
Basford,  in  Great  Britain,  who  was  rewarded  with  forty  guineas  by  the  Society  of  Arts. 
The  invention  chiefly  consists  in  expanding  a  set  of  bars  parallel  to  the  axis  of  a 
crane,  by  means  of  which,  the  velocity  of  the  rope  in  raising  weights  may  be  dimi- 
nished or  increased,  in  proportion  to  the  load  which  is  to  be  raised.  An  engraving 
and  description  of  this  crane  may  be  seen  in  the  Transactions  of  the  Society  for  the 
encouragement  of  Arts,  vol.  12;  or  in  the  Philosoph.  Mag.  April,  1804,  p.  270. 
VOL.  IT.  K 


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and,  I  believe,  might  be  built  in  a  room  8 
teet  in  width  :  the  gib  being  on  the  out- 
side of  the  room. 

Three  trundles,  with  different  numbers 
of  slaves,  are  applied  to  the  cogs  of  an  ho- 
rizontal wheel  with  an  upright  axle  ;  and 
the  rope  that  draws  up  the  weight  coils 
round  the  axle.  The  wheel  has  ninety-six 
cogs,  the  largest  trundle  twenty- four 
staves,  the  next  iargest  has  twelve,  and 
the  smallest  has  six.  So  that  the  largest 
trundle  makes  four  revolutions  for  one 
revolution  of  the  wheel :  the  next  makes 
tight,  and  the  smallest  makes  sixteen.  A 
winch  is  occasionally  put  upon  the  axis  of 
either  of  these  trundles,  for  turning  it ; 
that  trundle  being  then  used  which  gives 
a  power  best  suited  to  the  weight :  and 
the  Dandle  of  the  winch  describes  a  cir- 
cle in  every  revolution  equal  to  twice  the 
circumference  of  the  axle  of  the  wheel.  So 
that  the  length  of  the  winch  doubles  the 
power  gained  by  each  trundle. 

As  the  power  gained  by  any  machine  or 
engine  whatever,  is  in  direct  proportion  as 
the  velocity  of  the  power  is  to  the  veloci- 
ty of  the  weight;  the  powers  of  this  crane 
are  easily  estimated,  and  are  as  follows. 

If  the  winch  be  put  upon  the  axle  of 
the  largest  trundle,  and  turned  four  times 
round,  the  wheel  and  axle  will  be  turned 
once  round  :  and  the  circle  described  by 
the  power  that  turns  the  winch,  being,  in 
each  revolution,  double  the  circumfer- 
ence of  the  axle,  when  the  thickness  of 
the  rope  is  added  thereto  ;  the  power 
goes  through  eight  times  as  much  space 
as  the  weight  rises  through  :  and  there- 
fore (making  some  allowance  ior  friction) 
a  man  will  raise  eight  times  as  much 
weight  by  this  crane  as  he  would  by  his 
natural  strength  without  it :  the  power,  in 
this  case,  being  as  eight  to  one. 

If  the  winch  be  put  upon  the  axis  of 
the  next  trundle,  the  power  will  be  as  six- 
teen to  one,  because  it  moves  sixteen 
times  as  fast  as  the  weight  moves. 
•  If  the  winch  be  put  upon  the  axis  of 
the  smallest  trundle,  and  turned  round, 
the  power  will  be  as  thirty  !  wo  to  one. 

But  if  the  weight  should  be  too  great, 
even  for  this  power  to  raise,  the  power 
may  be  doubled  by  drawing  up  the  weight 
by  one  of  the  parts  of  a  double  rope,  go- 
ing under  a  pulley  in  the  moveable  block, 
which  is  hooked  to  the  weight  below  the 
arm  of  the  gib  ;  and  then  the  power  will 
be  as  sixty-four  to  one.  That  is,  a  man 
could  then  raise  sixty -four  times  as  much 
weight  by  the  crane  as  he  could  raise  by 
his  natural  strength  without  it ;  because, 
for  every  inch  that  the  weight  rises,  the 
working  power  will  move  through  sixty- 
four  inches. 


By  hanging  a  block  with  two  pullies  to 
the  arm  of  the  gib,  and  having  two  pullies 
in  the  moveable  block  that  rises  with  the 
weight,  the  rope  being  doubled  over  and 
under  the  pullies,  the  power  of  the  crane 
will  be  as  128  to  one.  And  thus,  by  in- 
creasing the  number  of  pullies,  the  power 
may  be  increased  as  much  as  you  please  : 
always  remembering,  that  the  larger  the 
pullies  are,  the  less  is  their  friction. 

While  the  weight  is  drawing  up,  the 
ratch-teeth  of  a  wheel  slip  round  below  a 
catch  or  click  that  falls  successively  into 
them,  and  so  hinders  the.  crane  from  turn- 
ing backward,  and  detains  the  weight  in 
any  part  of  its  ascent,  if  the  man  who 
works  at  the  winch  should  accidentally 
happen  to  quit  his  hold,  or  choose  to  rest 
himself  before  the  weight  be  quite  drawn 
up. 

In  order  to  let  down  the  weight,  a  mart 
pulls  down  one  end  of  a  lever  of  the  se- 
cond kind,  which  lifts  the  catch  of  the 
ratchet-wheel,  and  gives  the  weight  liber, 
ty  to  descend.  But,  if  the  descent  be  too 
quick,  he  pulls  the  lever  a  little  farther 
down,  so  as  to  make  it  rub  against  the 
outer  edge  of  a  round  wheel ;  by  which 
means  he  lets  down  the  weight  as  slowly 
as  he  pleases  :  and,  by  pulling  a  little  har- 
der, he  may  stop  the  weight,  if  needful, 
in  any  part  of  its  descent.  If  he  acciden- 
tally quits  hold  of  the  lever,  the  catch  im- 
mediately falls,  and  stops  both  the  weight 
and  the  whole  machine- 

This  crane  is  represented  in  Plate  5* 
where  A  is  the  great  wheel,  and  B  its 
axle  on  which  the  rope  C  winds.  This 
rope  goes  over  a  pulley  D  in  the  end  of 
the  arm  of  the  gib  E,  and  draws  up  the 
weight  F,  as  the  winch  G  is  turned  round. 
H  is  the  largest  trundle,  I  the  next,  and 
K  is  the  axis  of  the  smallest  trundle, 
which  is  supposed  to  be  hid  from  view  by 
the  upright  supporter  L.  A  trundle  M  is 
turned  by  the  great  wheel,  and  on  the  axis 
of  this  trundle  is  fixed  the  ratchet-wheel 
N,  into  the  teeth  of  which  the  catch  O 
falls.  P  is  the  lever,  from  which  goes  a 
rope  QQ,  over  a  pulley  R  to  the  catch  ; 
one  end  of  the  rope  being  fixed  to  the 
lever,  and  the  other  end  to  the  catch.  S 
is  an  elastic  bar  of  wood,  one  end  of  which 
is  screwed  to  the  floor  :  and,  from  the 
other  end  goes  a  rope  (out  of  sight  in  the 
figure)  to  the  farther  end  of  the  lever, 
beyond  the  pin  or  axis  on  which  it  turns 
in  the  upright  supi>orter  T.  The  use  of 
this  bar  is  to  keep  up  the  lever  from  rub- 
bing against  the  edge  of  the  wheel  U, 
and  to  let  the  catch  keep  in  the  teeth  of 
the  ratchet-wheel  :  but  a  weight  hung  to 
the  farther  end  of  the  lever  would  do  full 
as  well  as  the  elastic  bar  and  rope. 


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When  the  lever  is  pulled  down,  it  lifts 
the  catch  out  of  the  ratchet-wheel,  by 
means  of  the  rope  QQ,  and  gives  the 
weight  F  liberty  to  descend  :  but  if  the 
lever  P  be  pulled  a  little  farther  down 
than  what  is  sufficient  to  lift  the  catch  O 
out  of  the  ratchet-wheel  N,  it  will  rub 
against  the^  edge  of  the  wheel  U,  and 
thereby  hinder  the  too-quick  descent  of 
the  weight ;  and  will  quite  stop  the  weight 
if  pulled  hard.  And  if  the  man  who  pulls 
the  lever,  should  happen  inadvertently  to 
let  it  go,  the  elastic  bar  will  suddenly  pull 
it  up  and  the  catch  will  tall  down  and  stop 
the  machine. 

"WW  are  two  upright  rollers  above  the 
axis  or  upper  gudgeon  of  the  gib  E  :  their 
use  is  to  let  the  rope  C  bend  upon  them, 
as  the  gib  is  turned  to  either  side,  in  or- 
der to  bring  the  weight  over  the  place 
where  it  is  intended  to  be  let  down. 

N.  B.  The  rollers  ought  to  be  so  pla- 
ced, that  if  the  rope  C  be  stretched  close 
by  their  utmost  sides  the  half  thickness 
'  of  the  rope  may  be  perpendicularly  over 
the  centre  of  the  upper  gudgeon  of  the 
gib.  For  then,  and  in  no  other  position  of 
the  rollers,  the  length  of  the  rope  between 
the  pulley  in  the  gib  and  the  axle  of  the 
great  wheel  will  be  always  the  same,  in 
all  positions  of  the  gib  :  and  the  gib  will 
remain  in  any  position  to  which  it  is  turn- 
ed. 

When  either  of  the  trundles  is  not  turn- 
ed by  the  winch  in  working  the  crane,  it 
may  be  drawn  off  from  the  wheel,  after 
the  pin  near  the  axis  of  the  trundle  is 
drawn  out,  and  the  thick  piece  of  wood  is 
raised  a  little  behind  the  outward  suppor- 
ter of  the  axis  of  the  trundle-  But  this  is 
not  material ;  for,  as  the  trundle  has  no 
friction  on  its  axis  but  what  is  occasioned 
by  its  weight,  it  will  be  turned  by  the 
wheel  without  any  sensible  resistance  in 
working  the  crane 

Of  ITheel  enrriagts. — The  structure  of 
wheel-carriages  is  generally  so  well  known, 
that  it  would  be  needless  to  describe 
them  ;  and  therefore,  we  shall  only  point 
out  some  inconveniencies  attending  the 
common  method  of  placing  the  wheels, 
and  loading  the  waggons. 

In  coaches,  and  all  other  four-wheeled 
carriages,  the  fore-wheels  are  made  of  a 
less  size  than  the  hind  ones,  both  on  ac- 
count of  turning  short,  and  to  avoid  cut- 
ting the  braces ;  otherwise,  the  carriage 
would  go  much  easier,  if  the  fore-wheels 
were  as  high  as  the  hind  ones :  and  the 
higher  the  better,  because  they  would 
sink  to  less  depths  in  little  hollowing*  in 
the  roads,  and  be  the  more  easily  drawn 
out  of  them.  But  carriers  and  coachmen 
give  another  reason  for  making  the  fore- 


wheels  much  lower  than  the  hind-wheels  : 
merely,  that  when  they  are  so,  the  hind- 
wheels  help  to  push  on  the  fore  ones  ; 
which  is  too  unphilosophical  and  absurd 
to  deserve  a  refutation  ;  and  yet,  for  their 
satisfaction,  we  shall  show  by  experiment 
that  it  has  no  existence  but  in  their  own 
imaginations. 

It  is  plain  that  the  small  wheels  must 
turn  as  much  oftener  round  than  the  great 
ones,  as  their  circumferences  are  less  ; 
and  therefore,  when  the  carriage  is  load- 
ed equally  heavy  on  both  axles,  the  fore- 
axle  must  sustain  as  much  more  friction, 
and  consequently  wear  out  as  much  soon- 
er, than  the  hind-axle,  as  the  fore -w  heels 
are  less  than  the  hind  ones.  But  the  great 
msifortune  is,  that  all  the  carriers  to  a  man 
do  obstinately  persist,  against  the  clearest 
reason  and  demonstration,  in  putting  the 
heavier  part  of  the  load  upon  the  fore-axle 
of  the  waggon  ;  which  not  only  makes 
the  friction  greatest  ,  where  it  ought  to  be 
least,  but  also  presses  the  fore -wheels 
deeper  into  the  ground  than  the  hind- 
wheels,  notwithstanding  the  fore-wheels, 
being  less  than  the  hind  ones,  are  with  so 
much  the  greater  difficulty  drawn  out  of 
a  hole  or  over  an  obstacle,  even  supposing 
the  weights  on  their  axles  were  equal. 
For  the  difficulty,  with  equal  weights,  will 
be  as  the  depth  of  the  hole  or  height  of 
the  obstacle  is  to  the  semidiameter  of  the 
wheel.  Thus,  if  we  suppose  the  small 
wheel  J)  (Fig.  3,  Plate  IV.)  of  the  wag- 
gon A  B  to  fall  into  a  hole  of  the  depth 
E  E,  which  is  equal  to  the  semidiameter 
of  the  wheel,  and  the  waggon  to  be  drawn 
horizontally  along,  it  is  evident,  that  the 
point  E  of  the  small  wheel  will  be  drawn 
directly  against  the  top  of  the  hole ;  and 
therefore,  all  the  power  of  horses  and 
men  wili  not  be  able  to  draw  it  out  unless 
the  ground  gives  way  before  it.  Whereas, 
if  the  hind-wheel  G  fall  into  such  a  hole, 
it  sinks  not  near  so  deep  in  proportion  to 
its  semidiameter ;  and  therefore,  the  point 
G  of  the  large  wheel  will  not  be  drawn 
directly,  but  obliquely,  against  the  top  of 
tiie  hole ;  and  so  will  be  easily  got  out  of 
it  Add  to  this,  that  as  the  small  wheel 
will  often  sink  to  the  bottom  of  a  hole,  in 
which  a  great  wheel  will  go  but  a  very 
little  way,  the  small  wheels  ought  in  all 
reason  to  be  loaded  with  less  weight  than 
the  great  ones  ;  and  then  the  heavier  part 
of  the  load  would  be  less  jolted  upward 
anddownwaid,  and  the  horses  tired  so 
much  the  less,  as  their  draught  raised  the 
load  to  less  heights. 

It  is  true,  that  when  the  waggon-road 
is  much  up  hill,  there  may  be  danger  in 
loading  the  hind-part  much  heavier  than 
the  fore-part ;  for  then  the  weight  would 


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overhang  the  hind-axle,  especially  if  the 
load  be  high,  and  endanger  tilting  up  the 
fore -wheels  from  the  ground.  In  tins  case, 
the  safes-  way  would  be  to  load  it  equally 
heavy  on  both  axles  ;  and  then,  us  much 
more  of  the  weight  would  be  thrown  up- 
on  the  hind-axle  than  the  fore  one,  as  the 
ground  rises  from  a  level  below  the  car- 
riage. But  as  this  seldom  happens,  and 
when  it  does,  a  small  temporary  weight 
laid  upon  the  pole  between  the  horses 
would  overbalance  the  danger ;  and  this 
Weight  be  thrown  into  the  waggon  when  it 
comes  to  level  ground  ;  it  is  strange  that 
an  advantage  so  plain  and  obvious  as 
would  arise  from  loading  the  hind-wheels 
heaviest,  should  not  be  laid  hold  of,  by 
compjying  with  this  method. 

To  confirm  these  reasonings  by  an  ex- 
periment :  let  a  small  model  of  a  waggon 
be  made,  with  its  fore -wheels  2$  inches 
in  diameter,  and  its  hind-wheeis  4^;  the 
whole  model  weighing  about  20  ounces. 
Let  this  little  carriage  be  loaded  any  how 
with  weights,  and  have  a  small  cord  tied 
to  each  of  its  ends,  equally  high  from  the 
ground  it  rests  upon  ;  and  let  it  be  drawn 
along  a  horizontal  board,  first  by  a  weight 
in  a  scale  hung  to  the  cord  at  the  fore 
part ;  the  cord  going  over  a  pulley  at  the 
end  of  the  board,  to  facilitate  the  draught, 
and  the  weight  just  sufficient  to  draw  it 
along.  Then,  turn  the  carriage,  and  hang 
the  scale  and  weight  to  the  hind-cord,  and 
it  will  be  found  to  move  along  with  the 
same  velocity  as  at  first;  which  shows 
that  the  power  required  to  draw  the  car- 
riage is  the  same,  whether  the  great  or 
the  small  wheels  be  foremost ;  and  there- 
fore the  great  wheels  do  not  help  in  the 
least  to  push  on  the  small  wheels  in  tlie 
road. 

Hang  the  scale  to  the  fore-cord,  and 
place  the  fore-wheels  (which  are  the  small 
ones)  in  two  holes,  cut  three-eighth  parts 
of  an  inch  deep  into  the  board ;  and  then 
put  a  weight  of  32  ounces  into  the  car- 
riage, over  the  fore-axle,  and  an  equal 
weight  over  the  hind  one  :  this  done,  put 
44  ounces  into  the  scale,  which  will  be 
just  sufficient  to  draw  out  the  fore-wheels: 
but  if  this  weight  be  taken  out  of  the  scale, 
and  one  of  16  ounces  put  into  its  place,  if 
the  hind-wheels  be  placed  in  the  holes,  the 
16-ounce  weight  will  draw  them  out ; 
which  is  little  more  than  a  third  part  of 
what  was  necessary  to  draw  out  the  fore- 
wheels.  This  shows,  that  the  larger  the 
wheels  are,  the  less  power  will  draw  the 
carriage,  especially  on  rough  ground 

Put  64  ounces  o\er  the  axic   of  the 
2mui-wheels,  ar.d  32  over  the  axle  of  the 
fore  ones,  in  the  carriage,  and  place  the  ! 
Fore-wheels  in  the  holes ;  then  put  38  | 


ounces  into  the  scale,  which  will  just  draw 
out  the  fore- wheels ;  and  when  the  hind 
ones  come  to  the  hole  they  will  find  but 
very  little  resistance,  because  they  sink 
but  a  little  way  into  it. 

But  Shift  the  weights  in  the  carriage,  by 
putting  the  32  ounces  upon  the  hind-axle, 
and  the  64  ounces  upon  the  fore  one,  and 
place  the  fore-wheels  in  the  holes :  then, 
if  76  ounces  be  put  into  the  scale,  it  will 
be  found  no  more  than  sufficient  to  draw 
out  tliese  wheels  This  is  double  the 
power  required  to  draw  them  out,  when 
the  lighter  part  of  the  load  was  put  upon 
them:  which  is  a  plain  demonstration  of 
the  absurdity  of  putting  the  heaviest  part 
of  the  load  in  the  fore  part  of  the  wag- 
gon. 

Every  one  knows  what  an  outcry  M  as 
made  by  the  generality,  if  not  the  whole 
body,  of  the  carriers,  against  the  broad- 
wheel  act ;  and  how  hard  it  was  to  per- 
suade them  to  comply  with  it,  even 
though  the  government  allowed  them  to 
draw  with  more  horses,  and  carry  greater 
loads,  than  usual.  Their  principal  objec- 
tion was,  that  as  a  broad  wheel  must 
touch  the  ground  in  a  great  many  more 
points  than  a  narrow  wheel,  the  friction 
must  of  course  be  just  so  much  the  great- 
er; and  consequently,  there  must  be  so 
many  more  horses  than  usual  to  draw  the 
waggon.  I  believe  that  the  majority  of 
the  people  were  of  the  same  opinion,  not 
considering,  that  if  the  whole  weight  of 
the  waggon  and  load  in  it  bears  upon  a 
great  many  points,  each  sustains  a  propor- 
tionally less  degree  of  weight  and  fric- 
tion, than  when  it  bears  only  upon  a  few 
points ;  so  that  what  is  wanting  in  one, 
is  made  up  in  the  other;  and  therefore 
will  be  just  equal  under  equal  degrees  of 
weight ;  as  may  be  shown  by  the  follow- 
ing plain  and  easy  experiment. 

Let  one  end  of  a  piece  of  packthread  be 
fastened  to  a  brick,  and  the  other  end  to  a 
common  scale  for  holding  weights  ;  then 
lay  the  brick  edgewise  on  a  table,  and, 
letting  the  scale  hang-  under  the  edge  of 
the  table,  put  as  much  weight  into  the 
scale  as  will  just  draw  the  brick  along  the 
table.  Then  taking  back  the  brick  to  its 
former  place,  lay  it  fiat  on  the  table,  and 
the  same  weight  in  the  scale  as  before  will 
draw  it  along  with  the  same  ease  as  when 
it  lay  upon  its  edge.  In  the  former  case, 
the  brick  may  be  considered  as  a  narrow 
wheel  on  the  ground  ;  and  in  the  latter,  as 
a  broad  wheel.  And  since  the  brick  is 
drawn  along  with  equal  ease,  whether  its 
broad  side  or  narrow  edge  touches  the 
table,  it  shows  that  a  broad  wheel  might 
be  drawq  along  the  ground  wj  the  same 
ease  as  a  narrow  one  (supposing  them 


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equally  heavy)  even  though  they  should 
drag,  and  not  roll,  as  they  go  along. 

As  narrow  wheels  are  always  sinking  in 
to  the  ground,  especially  when  the  heavi- 
est part  of  the  load  lies  upon  them,  they 
must  be  considered  as  going  constantly  up 
hill,  even  on  level  ground;  and  their  sides 
must  sustain  a  gveat  deal  ot"  friction  by 
nibbing  against  the  ruts  made  by  them 
But  both  these  inconveniences  are  avoided 
by  broad  wheels  ;  which,  instead  of  cut- 
ting and  ploughing  up  the  roads,  roll 
them  smooth,  and  harden  them,  as  expe- 
rience testifies  in  places  where  they  have 
been  used,  especially  either  on  vvettish  or 
sandy  ground;  though  after  all  it  must  be 
confessed,  that  they  will  not  do  in  stiff 
clayey  crossroads;  because  they  would 
soon  gather  up  as  much  clay  as  would  be 
almost  equal  to  the  weight  of  an  ordinary 
load. 

If  the  wheels  were  always  to  go  upon 
smooth  and  level  ground,  the  best  way 
would  be  to  make  the  spokes  perpendicu- 
lar to  the  naves,  that  is,  to  stand  at  right 
angles  to  the  axles  ;  because  they  would 
then  bear  the  weight  of  the  load  perpen- 
dicularly, which  is  the  strongest  way  for 
wood.  But  because  the  ground  is  gene- 
rally uneveo,  one  wheel  often  falls  into  a 
cavity  or  rut  when  the  other  does  not ; 
and  then  it  bears  much  more  of  the 
weight  than  the  other  does  :  in  which  case, 
concave  or  dishing  wheels  are  best,  be- 
cause when  one  falls  into  a  rut,  and  the 
other  keeps  upon  high,  ground,  the  spokes 
become  perpendicular  in  the  rut,  and 
therefore  have  the  greatest  strength  when 
the  obliquity  of  the  load  throws  most  of  its 
weight  upon  them ;  while  those  on  the 
high  ground  have  less  weight  to  bear, 
and  therefore  need  not  be  at  their  full 
strength  ;  so  that  the  usual  way  of  making 
the  wheels  concave  is  by  much  the  best 

The  axle  of  the  wheels  ought  to  be  per- 
fectly straight,  that  the  rims  of  the  wheels 
may  be  parallel  to  each  other ;  for  then 
they  will  move  easiest,  because  they  will 
be  at  liberty  to  go  on  straight  forward. 
But  in  the  usual  way  of  practice,  the  axles 
are  bent  downward  at  their  ends,  which 
brings  the  edges  of  the  wheels  next  the 
ground  nearer  to  one  another  than  their 
opposite  or  higher  edges  are  :  and  this  not 
only  makes  the  wheels  drag  sidewise  as 
they  go  along,  and  gives  the  load  much 
greater  power  of  crushing  them  than 
when  they  are  parallel  to  each  other ;  but 
also  endangers  the  over-turning  of  the 
carriage  when  any  wheel  falls  into  a  hole 
or  rut ;  or  when  the  carriage  goes  on  a 
road  which  has  one  side  lower  than  the 
other,  as  along  the  side  of  a  hill.  Thus  (in 
the  hind  view  of  a  waggon  or  cart)  let 


A  E  and  B  F  Fig  4.  be  the  great  wheels 
parallel  to  each  other,  on  their  straight 
axle  A\  and  // CI  the  carriage  loaded 
with  heavy  goods  from  C  to  G.  Then,  as 
the  carriage  goes  on  in  the  oblique  road 
A  a  B.  the  centre  of  gravity  of  the  whole 
machine  and  load  will  be  at  C;  and  the 
line  Df  direction  Cd  B  falling  within  the 
wheel  B  F,  the  carriage  will  not  overset. 
But  if  the  wheels  be  inclined  to  each  other 
on  tne  ground,  as  A  E  and  B  F  are,  Fig. 
5.  and  the  machine  be  loaded  as  before, 
from  C  to  G,  the  line  of  direction  C  d  B 
falls  without  the  wheel  B  F,  and  the 
whole  machine  tumbles  over.  When  it 
is  loaded  with  heavy  goods,  (such  as  lead 
or  iron)  which  lie  low,  it  may  travel  safe- 
ly upon  an  oblique  road  so  long  as  the 
centre  of  gravity  is  at  C,  Fig.  4.  and  the 
line  of  direction  C  d  falls  within  the 
wheels  ;  but  if  it  be  loaded  high  with 
lighter  goods  (such  as  wool-packs)  from 
C'to  L,  Fig.  6.  the  centre  of  gravity  is  rais- 
ed from  C  to  K,  which  throws  the  line  of 
direction  Kk  without  the  lowest  edge  of 
the  wheel  B  F>  and  then  the  load  oversets 
the  waggon. 

If  there  be  some  advantage  from  small 
fore-wheels,  on  account  of  the  carriage 
turning  more  easily  and  short  than  it  can 
be  made  to  do  when  they  are  large,  there 
is  at  least  as  great  a  disadvantage  attend 
ing  them,  which  is,  that  as  their  axle  is 
below  the  level  of  the  horses'  breast,  the 
horses  not  only  have  the  loaded  carriage 
to  draw  along,  but  also  part  of  its  weight 
to  bear,  which  tires  them  sooner,  and 
makes  them  grow  much  stifTer  in  their 
hams,  than  they  would  do  if  they  drew  on 
a  level  with  the  fore-axle  :  and  for  this 
reason,  we  find  coach-horses  soon  become 
unfit  for  riding.  So  that  on  all  accounts 
it  is  plain,  that  the  fore-wheels  of  all  car- 
riages ought  to  be  so  high,  as  to  have 
their  axles  even  with  the  breast  of  the 
horses  ;  which  would  not  only  give  the 
horses  a  fair  draught,  but  likewise  keep- 
them  longer  fit  for  drawing  the  carriage. 

Of  Compound  Machines. — If  by  any 
power  you  are  able  to  raise  a  pound  with  " 
a  given  velocity,  it  will  be  impossible,  by 
the  help  of  any  machine,  to  raise  two 
pounds  with  the  same  velocity ;  yet,  by 
the  assistance  of  a  machine,  you  may  raise 
two  pounds  with  half  that  velocity,  or  even 
one  thousand  with  the  thousandth  part  of 
that  velocity  ;  but  still  there  is  no  greater 
quantity  of  motion  produced,  when  a  thou- 
sand pounds  are  moved,  than  when  oiu- 
pound  is  moved ;  the  thousand  pounds 
moving  proportionally  slower. 

No  real  gain  of  force  is,  therefore,  ob- 
tained by  mechanical  contrivances ;  on 
the  contrary,  from  friction  and  other  can- 


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ses,  force  is  always  lost ;  but  by  machines 
we  are  able  to  give  a  more  convenient  di- 
rection to  the  moving-  power,  and  to  ap- 
ply iis  action  at  some  distance  from  the 
body  to  be  moved,  which  is  a  circumstance 
of  infinite  importance.  By  machines  also, 
we  can  so  modify  the  energy  of  the  mov- 
ing power,  as  to  obtain  effects  which  it 
could  not  produce  without  this  modifica- 
tion. 

In  machines  composed  of  several  of  the 
mechanical  powers,  the  power  will  be  to 
the  weight,  when  ihey  are  in  equilibrio, 
in  a  proportion  formed  by  the  multiplica- 
tion of  the  several  proportions  which  the 
power  bears  to  the  weight  in  every  sepa- 
rate mechanical  power  of  which  the  ma- 
chine consists. 

Suppose  a  machine,  for  instance,  com- 
posed of  the  axle  in  the  wheel,  and  a  pul- 
ley ;  let  the  axle  and  wheel  be  such,  that 
a  power  consisting  of  one-sixth  of  the 
weight  will  balance  it ;  and  let  the  pullies 
be  such,  that  by  means  of  them  alone,  a 
power  equal  to  one-fourth  of  the  weight 
would  support  it :  then,  by  means  of  the 
axle  in  the  wheel,  and  the  pullies  pombin- 
ed,  a  power  equal  to  one-fourth  of  one- 
sixth,  that  is,  of  the  weight,  will  be 
in  equilibrio  with  it. 

In  contriving  machines,  simplicity  ought 
particularly  to  be  attended  to  ;  for  a  com- 
plicated machine  is  not  only  more  expen- 
sive, and  more  apt  to  be  out  of  order,  but 
there  is  also  a  greater  degree  of  friction 
in  proportion  to  the  number  of  rubbing 
parts. 

Whatever  be  the  construction  of  a  ma- 
chine, its  power  will  always  be  in  propor- 
tion to  the  velocity  of  the  power  to  the 
weight ;  and  so  that  this  is  obtained  in  the 
greatest  degree  that  circumstances  will 
admit,  or  that  are  necessary,then  the  fewer 
parts  the  better 

It  is  evident,  from  the  principles  alrea- 
dy laid  down,  that  the  velocity  of  a  wheel 
is  to  that  of  a  pinion,  or  smaller  wheel 
which  is  driven  by  it,  in  proportion  to  the 
diameter,  circumference,  or  number  of 
teeth  in  the  pinion  to  that  of  the  wheel. 
Thus,  if  the  number  of  teeth  in  a  wheel 
be  60,  and  those  of  the  pinion  5,  then  the 
pinion  will  go  12  times  round  for  once  of 
the  wheel,  because  60,  divided  by  5,  gives 
12  for  a  quotient. 

Hence,  if  you  have  any  number  of 
wheels  acting  on  so  many  pinions,  you 
must  divide  the  product  of  the  teeth  in 
the  wheels  by  those  in  the  pinions  ;  and  the 
quotient  will  give  the  number  of  turns  of 
the  last  pinion  in  one  turn  of  the  first 
wheel.  Thus,  if  a  wheel  A  (Fig.  1  Plate 
VIII.)  of  48,  acts  on  a  pinion  B  of  8,  on 
whose  axis  there  is  a  wheel  C  of  40,  driv- 


ing a  pinion  D  of  6,  carrying  a  wheel  E 
of  36,  which  moves  a  pinion  F  of  6,  car- 
rying an  index  ;  then  the  number  of  turns 
made  by  the  index,  will  be  found  in  this 
manner:  %8x^X3/==6f4f  °==240, 
the  number  of  turns  whicli  the  index  will 
make  while  the  wheel  A  goes  once  round. 

Any  number  of  teeth  on  the  wheels  and 
pinions  having  the  same  ratio,  will  give 
the  same  number  of  revolutions  to  an  axis  : 
thus,  f|X5¥0X  V^1  Vto°0=2405  as 
before.  It  therefore  depends  upon  the 
skill  of  the  engineer,  or  mechanic,  to  de- 
termine what  numbers  will  best  suit  his 
design. 

It  is  evident,  that  the  same  motion  may 
be  pei  formed,  either  by  one  wheel  and  pi- 
nion, or  by  many  wheels  and  pinions,  pro- 
vided the  number  of  turns  of  all  the  wheels 
bear  the  same  proportion  to  all  the  pi- 
nions which  that  one  wheel  bears  to  its 
pinion. 

When  a  wheel  is  moved  immediately 
by  the  power,  it  is  called  a  leader  ;  and  if 
there  is  another  wheel  on  the  same  axis, 
it  is  called  the  follower.  Tims  A,  being 
moved  immediately  by  the  power,  is  to  be 
considered  as  a  leader,  and  B  as  a  follow- 
er ;  the  wheel  C  being  driven  by  B,  be- 
comes a  leader,  and  D  a  follower;  E 
(Fig.  2)  is  a  leader,  and  the  cylinder  F 
may  be  considered  as  a  follower. 

Sometimes  the  same  wheel  acts  both  as 
a  leader  and  a  follower ;  as  in  Fig.  3,  where 
B  is  moved  by  A,  and  consequently  is  a 
leader,  while,  as  it  drives  C,  it  is  also  a 
follower.  Therefore,  as  to  multiply  both 
the  divisors  and  dividend  by  the  same 
number,  does  not  alter  the  quotient ;  in 
mechanical  calculations,  every  wheel  that 
is  both  a  leader  and  a  follower,  may  be 
entirely  omitted. 

The  power  of  a  machine  is  not  at  all 
altered  by  the  size  of  the  wheels,  provided 
the  proportions  to  each  other  are  the 
same.  Formerly  the  wheels  of  engines 
being  mostly  of  wood,  they  were  made  of 
a  large  size,  on  account  of  strength  ;  but 
now  that  cast-iron  wheels  are  so  easily 
made,  and  so  much  in  use,  the  size  of 
them  is  very  much  diminished,  which  has 
the  advantage  of  occupying  much  less 
room. 

Regulation  of  Motion  hy  Fly-Wheels. — 
In  all  machines,  the  moving  power  acts 
with  more  or  less  irregularity,  being 
sometimes  stronger,  and  at  other  times 
weaker. 

To  correct  this,  and  render  the  motion 
uniform,  an  additional  part,  called  a  fly, 
is  applied,  which  is  generally  either  a 
heavy  wheel,  or  a  cross  bar  loaded  with 
equal  weights.    This,  being  made  to  be* 


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MEC 


volve  about  its  axis,  keeps  up  tlie  force  of 
the  power,  and  distributes  it  equally  in  all 
parts  of  its  revolution  ;  for  on  account  of 
its  weight,  a  small  variation  in  force  does 
not  sensibly  alter  its  motion ;  whilst  fric- 
tion, and  the  resistance  of  the  machine, 
prevent  it  from  accelerating'.  If  the  mo- 
tion  of  the  machine  slackens,  it  helps  it 
forward;  if  it  tends  to  move  too  fast,  it 
will  keep  it  back. 

Every  regulating1 -wheel  should  be  fix- 
ed upon  that  axis  where  the  motion  is 
swiftest,  and  should  be  heavy  when  the 
motion  is  designed  to  be  slow,  and  light 
where  it  is  designed  to  be  swift.  In  all 
cases,  the  centre  of  motion  should  coin- 
cide with  the  centre  of  gravity  of  the 
wheel  The  axis  may  be  either  perpendi- 
cular, or  parallel  to  the  horizon. 

A  small  force  is  sufficient  to  put  a  hea- 
vy wheel  in  motion,  which,  if  long  conti- 
nued, will  accumulate  in  such  a  manner, 
as  to  produce  effects  in  raising^  weights 
and  overcoming  resistances,  which  could 
not  by  any  means  be  accomplished  by 
the  application  of  the  original  moving 
force. 

On  this  subject,  Mr.  Atwood  has  de- 
monstrated, that  a  force  of  20  pounds  ap- 
plied for  37  seconds  to  the  circumference 
of  a  cylinder  of  10  feet  radius,  and 
weighing  4713  pounds,  would,  at  the  dis- 
tance of  one  foot  from  the  centre,  give  an 
impulse  to  a  musket  ball  equivalent  to 
what  it  receives  from  a  full  charge  of 
gunpowder.  The  same  effect  would  be 
produced  in  six  minutes  and  ten  seconds 
by  a  man  turning  the  cylinder  with  a 
winch  one  foot  long,  in  which  he  constant- 
ly exerted  a  force  of  20  pounds.  In  this 
case,  however,  there  is  no  absolute  in- 
crease of  power  :  for  the  cylinder  has  no 
principle  of  motion  in  itself,  and  cannot 
have  more  than  it  receives. 

This  accumulation  of  motion,  however, 
in  heavy  wheels,  is  of  great  service  in  the 
construction  of  machines  for  various  pur- 
poses, rendering  them  much  more  power- 
ful, and  easy  to  be  worked  by  animals,  as 
well  as  more  regular  and  stead)-,  when 
set  in  motion  by  water,  or  any  inanimate 
power.  Hence  the  use  of  flies,  ballast- 
wheels,  &c.  which  are  commonly  sup- 
posed to  increase  the  power  of  a  machine, 
though  in  reality  they  take  something 
from  it,  and  act  upon  a  quite  different 
principle. 

In  all  machines  in  which  flies  are  used, 
a  considerably  greater  force  must  at  first 
be  applied  than  what  is  necessary  to  move 
the  machine  without  it,  or  the  fly  must 
have  been  set  in  motion  some  time  before 
it  is  applied  to  the  machine.  This  super- 
fluous power  is  collected  by  the  fly,  which 


serves  as  a  kind  of  reservoir  from  whence 
the  machine  may  be  supplied  when  the 
motion  slackens. 

This,  we  must  observe,  will  always  be 
the  case  with  machines  worked  by  ani- 
mals, for  none  are  able  to  exert  a  great 
power  with  absolute  constancy  ;  some  in- 
tervals of  rest,  even  though  almost  imper- 
ceptible, are  requisite,  otherwise  the  crea- 
ture's strength  would  in  a  short  time  be 
exhausted.  When  he  begins  to  move  in 
the  machine,  he  is  vigorous,  and  exerts  a 
great  power  ;  in  consequence  of  which  he 
overcomes  not  only  the  resistance  of  the 
machine  itself,  but  communicates  a  consi- 
derable degree  of  power  to  the  fly.  The 
machine,  when  moving,  yields  for  a  time 
to  a  smaller  impulse  ;  during  which  time 
the  fly  itself  acts  as  a  moving  power,  and 
the  animal  recovers  the  strength  he  has 
lost.  By  degrees,  however,  the  motion 
of  the  machine  decreases,  and  the  ani- 
mal is  obliged  to  renew  his  efforts.  The 
velocity  of  the  machine  would  now  be  con- 
siderably increased,  were  it  not  that  the 
fly  now  acts  as  a  resisting  power,  and  the 
greatest  part  of  the  superfluous  motion  is 
lodged  in  it,  so  that  the  increase  of  velo- 
city is  scarcely  perceptible.  Thus  the 
animai  has  time  to  rest  himself,  until  the 
machine  again  requires  an  increased  im- 
pulse, and  so  on  alternately. 

The  case  is  the  same  with  a  machine 
moved  by  water,  or  by  a  weight ;  for 
though  the  strength  of  these  does  not  ex- 
haust itself  like  that  of  an  animal,  yet  the 
yielding  of  the  parts  of  the  machine  ren- 
ders the  impulse  much  less  after  it  begins 
to  move  ;  hence  its  velocity  is  accelerated 
for  some  time,  until  the  impulse  becomes 
so  small,  that  the  machine  requires  an  in- 
crease of  power  to  keep  up  the  necessary 
motion.  Then  the  machine  slackens  its 
pace,  the  water  meets  with  more  resist- 
ance, and  of  consequence  exerts  its  pow- 
er more  fully,  and  the  machine  recovers 
its  velocity. 

But  when  a  fly  is  added  to  the  other 
parts,  this  acts  first  as  a  power  of  resist- 
ance, so  that  the  machine  does  not  ac- 
quire the  velocity  it  would  otherwise  do. 
When  it  next  begins  to  yield  to  the  pres- 
sure of  the  water,  and  the  impulse  of 
course  to  slacken,  the  fly  communicates 
part  of  its  motion  to  the  other  parts  ;  so 
that  if  the  machine  be  well  made,  there  is 
very  little  difference  in  the  velocity  per- 
ceptible. 

The  truth  of  what  is  here  advanced 
will  easily  be  seen,  from  considering  the 
inequality  of  motion  in  a  clock,  when  the 
pendulum  is  off,  and  how  very  regularly 
it  goes  when  regulated  by  a  pendulum, 
which  here  acts  as  a  fly. 


MEC 

Flies  are  particularly  useful  in  any  kind 
of  work  which  is  done  by  alternate  strokes, 
as  the  lifting  of  large  pestles,  pumping-  of 
water,  &c.    Jn  this  case,  the  weight  of  the 
wheel  employed  is  a  principal  object ;  and 
the  method  of  calculating  this,  is  to  com- 
pare it  with  the  weight  to  be  raised  at 
each  stroke  of  the  machine.    Thus,  sup- 
pose it  is  required  to  raise  a  pestle  30 
pounds  weight  to  the  height  of  one  foot, 
60  times  in  a  minute  ;  let  the  diameter  of 
the  fly  be  seven  feet,  and  suppose  the  pes- 
tle to  be  lifted  once  at  every  revolution  of 
the  fly;   we  must  then  consider  what 
weight  passing  through  22  feet  in  a  se- 
cond, will  be  equivalent  to  30  pounds 
moving  through  one  foot  in  a  second. 
This  will  be  30  divided  by  22,  or 
pounds.  Were  a  fly  of  this  kind  to  be  ap- 
plied, therefore,  and  the  machine  set  a- 
going,  the  fly  would  just  be  able  to  lift 
the  pestle  once,  after  the  moving  power 
was  withdrawn ;  but  by  increasing  the 
weight  of  the  fly  to  10,  12,  or  -0  pounds, 
the  machine,  when  left  to  itself,  would 
make  a  considerable  number  of  strokes, 
and  be  worked  with  much  less  labour 
than  if  no  fly  had  been  used,  though,  no 
doubt,  at  the  first,  it  would  be  found  a 
considerable  incumbrance  to  the  motion. 

This  is  equally  applicable  to  the  action 
of  pumps  ;  but  the  weight  which  can  be 
most  advantageously  given  to  a  fly,  has 
never  yet  been  determined  by  mechanics. 
It  is  certain,  however,  that  the  fly  does 
not  communicate  any  absolute  increase  of 
power  to  the  machine ;  for  if  a  man,  or 
other  animal,  is  not  able  to  set  any  me- 
chanical engine  in  motion  without  a  fly, 
he  will  not  be  able  to  do  it,  though  a  fly 
be  applied,  nor  will  he  be  able  to  keep  it 
in  motion,  though  set  a-going  with  a  fly, 
by  means  of  a  greater  power. 

On  the  application  of  Mtn  and  Horses, 
as  moving  powers  in  Machinery,  is? c. — A 
horse  draws  with  the  greatest  advantage, 
when  the  line  of  draught  is  not  level  with 
his  breast,  but  inclines  upwards,  making  a 
small  angle  with  the  horizontal  plane. 

A  horse  drawing  a  weight  over  a  single 
pulley,  can  draw  200  lbs.  for  eight  hours 
a  day,  and  walking  at  the  rate  of  2^  miles 
in  an  hour,  which  is  about  3^  feet  in  a  se- 
cond ;  and  if  the  same  horse  be  made  to 
draw  240  lbs.  he  can  work  but  six  hours  a 
day,  and  cannot  go  quite  so  fast.  To  this 
may  be  referred  the  working  of  horses  in 
all  sorts  of  mills  and  water-works,  where 
we  ought  to  know  as  near  as  we  can,  how 
much  we  make  every  horse  draw,  that 
we  may  judge  of  what  the  effect  will  be, 
when  proper  allowance  shall  have  been 
made  for  all  the  frictions  and  hindrances, 


MEC 

before  we  cause  any  machine  to  be 
erected. 

When  a  horse  draws  in  a  mill,  or  gin 
of  any  kind,  great  care  should  be  taken 
that  the  horse-walk,  or  circle  in  which  he 
moves,  be  large  enough  in  diameter  other- 
wise the  horse  cannot  exert  all  his 
strengih ;  for,  in  a  small  circle,  the  tan- 
gent (in  which  the  horse  draws)  deviates 
more  from  the  circle  in  which  the  horse  is 
obliged  to  go,  than  in  a  larger  circle. 
The  horse-walk  should  not  be  less  than 
40  feet  in  diameter,  when  tl  ere  is  room 
for  it.  In  a  walk  of  19  feet  diameter,  it 
has  been  calculated  that  a  horse  loses 
two-fifths  of  his  strength. 

The  worst  way  of  applying  the  force  of 
a  horse,  is  to  make  him  carry  or  draw  up 
hill ;  for,  if  the  hill  be  steep,  three  men 
will  do  more  than  a  horse  ;  each  man 
loaded  with  100  lb.  will  move  up  faster 
than  a  horse  that  is  loaded  with  3001b. 
This  is  owing  to  the  position  of  the  parts 
of  a  man's  body,  which  are  better  adapt- 
ed for  climbing  than  those  of  a  horse. 

As  a  horse,  from  the  structure  of  his 
body,  can  exert  most  strength  in  drawing' 
almost  horizontally  in  a  straight  line,  a 
man  exerts  the  least  strength  that  way  ; 
as  for  example,  if  a  man  weighing  1401b. 
walking  by  a  river  or  canal  side,  draws 
along  a  boat,  or  barge,  by  means  of  a  rope 
coming  over  his  shoulders,  or  otherwise 
fastened  to  his  body,  he  cannot  draw 
above  271b.  or  about  ^L.  of  what  a  horse 
can  draw  in  that  case.  Five  men  are 
about  equal  in  strength  to  one  horse,  and 
can  with  the  same  ease  push  round  the 
horizontal  beam  in  a  40  foot  walk ;  but 
three  of  the  same  men  will  push  round  a 
beam  in  a  19  foot  walk,  which  a  horse 
(otherwise  equal  to  five  men)  can  but 
draw  round. 

A  man  turning  an  horizontal  windlass  by 
a  handle,  or  winch,  should  not  have  above 
30  lbs.  weight  acting  against  him,  if  he  is 
to  work  ten  hours  a  day,  and  raise  the 
weight  at  the  rate  of  three  feet  and  a  half 
in  a  second.  This  supposes,  however, 
that  the  semi-diameter  of  the  windlass  is 
equal  to  the  distance  from  the  centre  to 
the  elbow  of  the  handle  ;  for  if  there  be 
a  mechanical  advantage,  as  there  usually 
is,  by  having  the  diameter  of  the  axle,  on 
which  the  rope  winds,  four  or  five  times 
less  than  the  diameter  of  the  circle  de- 
scribed by  the  hand,  then  may  the  weight 
(taking  in  also  the  resistance,  on  account, 
of  the  friction  and  stiffness  of  the  rope) 
be  four  or  five  times  greater  than  301b. ; 
that  is,  so  much  as  it  rises  slower  than 
the  hand  moves. 

In  this  operation,  the  effect  of  a  manV 


'■>rce  varies  in  every  part  of  the  circle  de- 
scribed by  the  handle.  The  greatest  force 
is,  when  a  man  pulls  the  handle  upwards 
from  about  the  height  of  his  knees  ;  and 
the  least  force  when  (the  handle  being  at 
lop)  he  thrusts  from  him  horizontally  ; 
then  again  the  effect  becomes  greater,  as 
a  mean  lays  on  his  weight  to  push  down 
the  handle  ;  but  that  action  cannot  be  so 
great  as  when  he  pulls  up,  because  he 
iays  on  no  more  than  the  whole  weight 
of  his  body  ;  whereas,  in  pulling,  he  can 
exert  his  whole  strength.  Lastly, he  has 
but  small  force  to  pull  the  handle  towards 
him  horizontally,  when  at  its  lowest. 

Let  us  suppose  a  man  of  moderate 
strength  to  weigh  140  lb.  he  may  in  the 
tour  principal  parts  of  pushing  and  puli 
ing,  in  the  whole  circumference  of  mo 
tion,  exert  the  following  forces,  viz.  in  the 
•strongest  point,  a  force  equal  to  160  lb. ; 
in  the  weakest,  a  force  equal  to  27  lb. ;  in 
the  next  strong  point,  130  lb.;  and  in  the 
last,  or  second  weak  point,  30  lb  Let  us 
add  all  these  forces  together,  which  will 
make  347 ;  which  divide  by  4,  and  we 
shall  have  84 Jib.  for  the  weight  that  a 
man  might  lift  by  a  winch,  if  he  could 
exert  his  whole  force  continually,  without 
stopping  to  take  breath;  but  as  that  can- 
not be,  the  weight  must  return,  and  over- 
power at  the  first  weak  point,  especially 
when  the  handle  moves  slowly,  as  it  must, 
if  a  man  would  exert  his  whole  strength 
all  round.  Besides,  for  raising  such  a 
weight,  we  must  suppose  the  man  acting 
always  along  the  tangent  of  the  circle  of 
motion,  which  does  not  happen  in  the  ope- 
ration. Then  there  must  be  a  Sufficient 
velocity  given  that  the  force  applied  at 
the  strong  points  may  not  be  spent  before 
the  hand  comes  to  the  weak  ones,  so  that 
it  is  difficult  for  a  man  to  continue  that 
irregular  motion ;  and  therefore,  when 
there  are  no  other  advantages,  the  resist- 
ance ought  to  be  but  30  lb.  If  a  fly  be 
added  to  the  windlass  when  the  motion  is 
pretty  quick,  as  about  four  or  five  feet  in 
a  second,  a  man  may  for  a  little  while  act 
with  a  force  of  80  lb.  and  work  a  whole 
day  with  a  resistance  of  40  lb. 

If  two  men  work  at  the  end  of  a  roller, 
or  windlass,  as  in  drawing  up  coals  or  ore 
from  a  wine,  or  water  from  a  well,  they 
may  more  easily  draw  up  70  lb.  (still  sup- 
posing the  weight  and  power  to  have 
equal  velocities)  that  one  man  can  30  lb. 
provided  the  elbow  of  one  of  the  handles 
be  at  right  angles  to  the  other ;  for  then 
one  man  will  act  at  the  strongest  point, 
when  the  other  acts  at  the  weakest  point 
of  the  revolution ;  by  which  means,  the 
two  men  will  mutually  and  successively 
help  one  another,  which  cannot  give  the 

VOL.  II. 


advantage  above-mentioned,  though  there 
is  some  little  force  gained  even  in  Chut  po- 
sition, because  one  man  pulling  while  the 
other  thrusts,  works  at  the  strongest  of 
the  two  weak  points,  whilst  the  other 
works  at  the  weakest,  and  so  helps  him 
a  little. 

Whefi's  man  carries  a  burden  upon  his 
back,  he  exerts  &  great  force  very  effec- 
tually, many  muscles  being  at  once  em- 
ployed in  that  operation  ;  the  muscles  of 
his  neck,  back,  and  loins,  keep  his  body 
and  head  in  the  proper  position  to  sustain 
the  weight ;  those  of  his  shoulders  and 
arms  help  to  keep  it  in  its  place  ;  and  the 
muscles  of  his  legs  and  thighs  raise  the 
weight  of  all  the  body  and  burden  as  the 
man  walks  along.  In  this  way  of  work- 
ing, three  men  do  mwch  more  than  a 
horse,  and  two  often  do  as  much,  as  may 
be  observed  in  the  daily  labour  of  the 
London  porters.  A  porter  will  carry 
200  lb.  and  walk  at  the  rate  of  three  miles 
an  hour  ;  a  coal-heaver  will  carry  i50  lb. 
but  then  he  does  not  go  far  with  his  load. 
Chairmen  do  not  act  with  the  same  mus- 
cles as  porters,  but  as  they  have  straps 
brought  down  from  their  shoulders  to  the 
poles  of  the  chair,  the  muscles  of  the  loins 
and  back  are  concerned,  and  likewise  the 
extensors  of  the  legs  and  thighs  ;  two  of 
them  will  walk  with  300  lb.  (that  is,l501b. 
each)  at  the  rate  of  four  miles  an  hour. 

The  last  and  most  effectual  way  of  a 
man's  exerting  his  strength,  is  in  rowing . 
a  boat ;  he  there  acts  with  more  muscles 
than  in  any  other  operation;  and  the 
weight  of  the  body  also  assists  him. 

To  describe  the  cycloid  and  epicycloid :  of 
use  In  shaping  the  teeth  of  wheels,  iSfc. 

If  a  point  or  pencil  a,  (Plate  6,  Fig.  12.) 
on  t  he  circumference  of  the  circle  B,  pro- 
cei  els  along  the  plane  a  C,  in  a  right  line, 
and  at  the  same  time  revolves  round 
its  centre,  it  will  describe  a  cycloid. 

And,  if  the  generating  circle  D,  (Fig. 
13  )  moves  along  the  circumference  of 
another  circle  E,  and  at  the  same  time 
turns  round  its  centre,  the  point  o  will 
describe  an  epicycloid. 

To  apply  the  cycloid  and  epicycloid  to  the 
teeth  of  -wheels,  pinions,  racks,  &c.  so  as 
to  cause  them  to  act  with  the  least  pos- 
sible wear,  or  loss  of  power  by  friction. 

Having  described  the  genesis  of  the  cy- 
cloid and  epicycloid,  it  becomes  necessa- 
ry to  shew  the  manner  of  applying  them, 
in  practice,  to  the  teeth  of  wheels,pinions, 
and  racks ;  and  to  the  cams,  or  lifting 
cogs,  of  forges,  mills  for  bruising  ore, 
L 


MEC 

pounding  gunpowder,  beating  flax,hemp, 
&c.  so  as  to  cause  them  to  act,  with  the 
least  possible  loss  of  power,  by  friction  ; 
and  first,  of  the  epicycloid. 

Fig.  1.  (see  Plates  VII.  Mechanics)  re- 
presents portions  of  a  wheel  and  pinion  ; 
AB,  and  CD,  are  the  pitch-lines,  or  pri- 
mitive diameters,  as  they  are  likewise 
termed  ;  those  parts  of  the  teeth  contain- 
ed between  the  pitch-lines  and  the  rims  of 
the  wheel  and  pinion,  are  to  be  made  ra- 
dii, or  shaped  to  iines  drawn  from  the  di- 
visions in  the  pitch-lines  to  the  centres  of 
the  wheel  and  pinion ;  the  curved  parts 
above  the  pitch-lines,  reaching  to  the  ends 
of  the  teeth,  must  be  portions  of  epicy- 
cloids ;  m  order  to  produce  which,  let 
two  segments  or  portions  of  circles,  equal 
to  the  radii  of  the  pitch-lines,  be  drawn 
upon  a  smooth  oaken  or  other  plank,  not 
less  than  half  an  inch  in  thickness,  and 
let  it  be  sawn  or  otherwise  exactly  shaped 
to  those  curves  ;  see  Figs  2  and  3  j  the 
first  of  which,  being pf  the  same  curvature 
with  the  pitch-line  of  the  pinion  CD,  and 
the  second  the  same  sweep  as  that  of  the 
wheel  \B,  a  hole  must  then  be  bored  ob- 
liquely in  each,  commencing  a  quarter  of 
an  inch  from  the  edge  on  one  side,  and 
terminating-  in  the  edge  of  the  opposite 
bide  ;  into  each  of  which  holes  a  nail,  &c 
must  be  driven  until  the  points  project  a 
little  below  the  holes,  as  at  EE;  these 
points  must  then  be  hied,  so  as  to  leave 
them  exactly  in  the  peripheries  of  the  cir- 
cles, just  long  enough  to  make  an  impres- 
sion upon  any  plane  surface  placed  be- 
neath them,  and  must  be  rounded  and 
made  conical,  so  as  to  trace  a  smooth 
even  line ;  then,  after  having  rubbed  the 
sides,  or  circular  edges  of  the  segments, 
with  powdered  resin,  fix  the  segment 
(Fig.  2.  fast  upon  the  pitch-line  of  the 
pinion  ;  and  apply  the  tracing  point  in  the 
other  segment  (Fig.  3  )  successively  to 
all  the  divisions  of  the  teeth  in  the  said 
pitch-line,  and  pressing  its  edge  close  to 
the  edge  of  the  fixed  segment,  cause  it  to 
roll  or  revolve  about  it,  without  slipping 
one  way  or  the  other,  until  it  shall  have 
described  the  curves  proper  for  all  the 
teeth  of  the  pinion  ;  then,  taking  off  the 
small  segment  from  the  pinion,  fasten  the 
larger  one  upon  the  pitch-line  of  the  wheel; 
and  proceed  to  describe  the  curves  of  the 
teeth  of  the  wheel,  with  the  tracing  point 
in  the  small  segment,  exactly  in  the  same 
manner  as  those  of  the  pinion. 

The  teeth  in  bevel-geei-,  should  also  be 
made  partly  radii  and  partly  epicycloidal ; 
but  to  describe  the  mode  of  applying  that 
curve  to  them,  would  far  exceed  our  limits 

We  shall  next  proceed  to  explain  the 
method  of  applying-  the  epicycloid  to  the 


MEC 

lifting  cogs  or  cams,  of  forge  hammers, 
or  other  similar  purposes,  where  both  the 
moving  bodies  describe  arcs  of  circles : 
in  this  case,  as  only  one  tooth  cog, or  cam, 
acts  at  a  time,  we  need  only  form  two 
segments  of  circles  :  one  corresponding 
with  the  radius  of  the  mill  shaft,  or  the 
place  where  the  cog  begins  to  act  upon 
the  hammer  tail,  as  CD,  (Fig.  4.)  and  the 
other  equal  to  the  distance  from  the  axis 
of  the  hammer  to  the  aforesaid  radius,  as 
AB  ;  then  fixing  the  segment  CD,  in  the 
manner  before-mentioned,  upon  axircle  of 
the  same  radius,  drawn  upon  any  fit  plane 
surface,  we  must  furnish  the  other  seg- 
ment. AB,  with  a  tracing  point,  and  pro- 
ceed as  before  to  describe  the  curves  pro- 
per for  the  lifting-  cogs  :  that  part  of  the 
hammer  tail,  upon  which  they  act,  requir- 
ing only  to  be  made  flat,  and  placed  in  a 
line  drawn  through  both  axes. 

Fig.  5,  represents  portions  of  a  rack  and 
pinion  :  CD,  the  primitive  diameter,  or 
pitch-line  of  the  pinion;  and  AB.the  pitch- 
line  of  the  rack  ;  the  sides  of  the  teeth  in 
the  pinion,  from  the  pitch-line  to  their  bot- 
toms, are  to  be  made  radii,  as  in  Fig.  1  ; 
but  the  sides  of  the  teeth  in  the  rack,  be- 
low the  pitch-line,  must  be  drawn  at  right 
angles  to  the  pitch-line:  the  curved  parts 
of  the  teeth  in  the  pinion,  and  rack  like- 
wise are  to  be  made  cycloidal,  by  form- 
ing a  circular  segment  corresponding  with 
the  radius  of  the  pitch-line  of  the  pinion  • 
and  a  straight-edge  or  ruler,  both  being- 
furnished  with  tracing-points  in  their 
edges ;  then  fixing  the  circular  segment 
fast  upon  the  pitch-line  of  the  pinion,  pro- 
ceed to  describe  all  the  curved  parts  of 
its  teeth,  by  placing  the  tracing-point  in 
the  edge  of  the  straight  ruler,  successive- 
ly in  all  the  divisions  in  the  pitch-line  of 
the  pinion,  and  rolling  it  either  one  way 
or  the  other,  upon  the  circular  segment, 
without  slipping ;  then,  fixing  the  straight- 
edge fast  upon  the  primitive  or  pitch-line 
of  the  rack,  take  oft'  the  circular  segment 
from  the  pinion,  and  placing  its  tracing- 
point  in  the  divisions  made  in  the  pitch- 
line  of  the  teeth  of  the  rack,  roll  it  upon 
the  straight-edge,  either  one  way  or  the 
other,  as  before  directed,  until  all  the 
curves  of  the  rack  teeth  are  also  traced. 

Fig.  6.  represents  portions  of  a  stamper 
of  a  mill  for  bruising  ore,  pounding  gun- 
powder, beating  hemp,  &c.  and  of  its  shaft 
with  lifting-cogs;  AB,  is  a  line  correspond- 
ing with  that  part  of  the  arm  of  the  stamp- 
er upon  which  the  lifting-cogs  first  act ; 
CD,  is  the  pitch-line  of  the  axis,  or  the 
bottom  of  the  curves  of  the  lifting-cogs  : 
in  this  case  we  need  not  be  at  the  trouble 
of  making  segments;  but  describing  a 
portion  of  a  circle  of  the  radius  of  the  said 


Mill  Work . 


H.Ander#an,  fc  . 


MEC 


pitch-line,  upon  any  plane  surface  of  wood, 
we  drive  a  number  of  small  nails,  or  tacks, 
into  the  said  circular  arc,  leaving  them 
standing"  half  an  inch  above  the  surface  of 
the  wood;  then  fixing  a  thread  to  the 
endmost  nail,  we  make  a  loop  at  its  other 
extremity,  in  which  we  place  a  tracing- 
point,  or  pencil,  E ;  and  keeping  the  thread 
stretched  tight,  cause  it  to  form  tangents 
to  the  circular  arc  CD ;  and  thus  the  tra- 
cer will  describe  a  curved  line,  being  a 
portion  of  a  cycloid,  upon  the  plane  sur- 
face of  wood ;  which  curved  line  is  the 
proper  form  for  the  lifting-cogs  of  the  mill- 
shaft  :  the  arm  of  the  stamper  should  be 
made  flat  at  the  part  where  the  lifting-cogs 
act  upon  it,  and  should  be  placed  in  a 
line  pointing  to  the  centre  of  the  mill- 
shaft,  at  the  time  the  cog  first  comes  into 
contact  with  it. 

To  form  a  templet,  or  Pattern  Tooth,  to 
facilitate  the  application  of  the  cycloid 
and  epicycloid,  to  the  teeth  of  wheels, 
pinions,  &c. 

As,  however,  it  would  in  all  cases  be 
tedious,  and  in  some  n  arly  impracticable, 
to  generate  these  lines  and  curves  upon 
every  tooth  in  a  wheel,  pinion,  rack,  &c. 
we  shall  describe  an  easy  mode  of  forming 
a  templet,  or  pattern  tooth,  and  the  man- 
ner of  applying  it  with  facility,  not  only 
to  the  large  teeth  of  wheels  and  pinions  in 
mill-work,  but  also  to  the  teeth  of  the 
smaller  wheels,  &c.  employed  in  cotton 
works,  clocks,  watches,  &c. 

In  order  to  which,  having  determined 
the  radii  of  the  pitch -lines,  and  made  seg- 
ments, corresponding  thereto ;  having  i 
likewise  determined  the  height  and  the 
depth  of  the  teeth,  and  divided  the  pitch- 
lines  into  teeth  and  spaces,  as  before : 
then,  for  wheels  and  pinions,  instead  of 
applying  the  segments  immediately  upon 
the  wheels  or  pinions  themselves,  we  take 
a  plate  of  brass  or  other  proper  metal, 
a,  a,  (Fig.  7.)  ;  and  fasten  it  (by  means  of 
pins,  driven  through  holes,  made  in  its 
corners)  upon  any  plane  surface  of  wood ; 
we  then  describe  upon  it,  by  means  of 
compasses  or  beam  compasses,  the  lines 
corresponding  with  the  primitive  diame- 
ter or  pitch-line,  and  tops  and  bottoms  of 
the  teeth  in  the  wheel  or  pinion  :  and  fix- 
ing the  correspondent  segment,  fast  upon 
its  pitch-line,  with  the  point  fixed  in  the 
other  segment,  describe  that  portion  of 
the  epicycloid  which  reaches  from  the 
pitch-line  to  the  tops  of  the  teeth  ;  then, 
after  having  taken  o<~  ;  fixed  segment, 
draw  a  radius  line  from  tne  commence- 
ment of  the  curve  in  the  pitch-line,  to  the 
bottoms  of  the  teeth  ;  and  taking  the  me- 
tal plate  off  from  the  plane  sw&ce,  accu- 


rately file  or  shape  one  edge  of  it  from  b 
to  b,  to  those  lines  so  drawn,  and  like- 
wise  shape  its  upper  and  lower  edges  to 
the  circular  arcs  described  upon  it ;  the 
extra  portion  from  c,  to  c,  may  likewise  be 
removed ;  then,  taking  a  piece  of  wood 
(or  in  case  of  small  works,  metal)  of  a 
proper  thickness  and  breadth,  and  long 
enough  to  extend  over  at  least  two  of  the 
teeth,  describe  upon  it  a  circular  arc,  d,dy 
exactly  equal  in  radius  to  the  tops  of  the 
teeth,  and  then  slitting  one  end  of  it  from 
b  to  d,  fix  into  that  slit,  the  metal  plate, 
before  described  by  that  part  of  it,  which 
extends  above  the  line  b,  d-  observing 
that  it  be  so  placed  in  the  slit,  as  exactly 
to  correspond  with  its  situation  when  ge- 
nerated ;  that  is  to  say,  that  the  radius 
line  of  the  templet,  may  point  exactly  to 
the  centre  of  the  circular  arc  d%  d,  of  the 
piece  of  wood  thus  slit ;  and  the  similar 
arc  b,  d,  of  the  templet,  be  in  contact  with 
that  arc  ;  it  must  then  be  fastened  in  that 
position,  by  drilling  holes  through  both 
pieces,  and  riveting  them  together,  so  as 
to  leave  a  projecting  shoulder  on  each 
side  of  the  templet,  as  shewn  by  Fig.  8 

Mr.  Oliver  Evans,  of  Philadelphia,  bag 
devoted  much  time  and  made  great  im« 
provements  in  mill  machinery,  and  other 
branches  of  mechanics.  A  tract  ot  which 
lie  is  the  author,  entitled,  Tbeyoung  mill- 
■Wright's  and  miller's  guide,  is  divided  into 
the  following  five  parts  : 

1.  Mechanics  and  Hydraulics,  shewing 
errors  in  the  old,  and  establishing  a  new 
system  of  theories  of  water  mills,  by  which 
the  power  of  mill-seats,  and  the  effects 
they  will  produce  may  be  ascertained  by 
calculation. 

2.  Rules  for  applying  the  theories  to 
practice,  tables  for  proportioning  mills  to 
the  power  and  fall  of  the  water,  and  rules 
for  finding  pitch  circles,  with  tables  from 
6  to  136  cogs. 

3.  Directions  for  constructing  and  using 
all  the  author's  patent  improvements  in 
mills. 

4.  The  art  of  manufacturing  meal  and 
flour  in  all  its  parts,  as  practised  by  the 
most  skilful  millers  in  America. 

5.  The  Practical  Mill  wright ;  contain- 
ing instructions  for  building  mills,  with 
tables  of  their  proportions  suitable  for  all 
falls  from  three  to  thirty -six  ieei  ;jwith  an 
Appendix,  containing  rules  for  discover- 
ing how  improvements  made  may  be  ex- 
emplified in  improving  the  art  of  cleaning 
grain,  hulling  rice,  warming  rooms,  and 
venting  smoke  by  chimneys,  &c. 

The  following  specification  of  sundry 
improvements  in  mill  machinery,  we  have 
been  favoured  with  by  Mr.  Evans,  the 
patentee. 

f  My  first  principle  is  to  elevate  the 


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meal  as  fast  as  it  is  ground  in  small  sepa- 
rate  parcels,  in  continued  succession  and 
rotation,  to  fall  on  the  cooling  floor,  to 
spread,  stir,  turn  and  expose  it  to  the  ac- 
tion of  the  air,  as  much  as  possible,  and 
to  keep  it  in  constant  and  continual  mo- 
tion, from  the  time  it  is  ground  until  it  be 
bohed :  this  I  do  to  give  the  air  full  action, 
to  extract  the  superfluous  moisture  from 
the  meal,  while  the  heat  generated  by  the 
friction  of  grinding'  will  repel  and  throw 
it  off,  and  the  more  effectually  dry  and 
cool  the  meal  fit  for  bolting  in  the  course 
of  the  operation,  and  save  time  and  ex- 
pence  to  the  miller.  Also  to  avoid  all  dan- 
ger from  fermentation  by  its  laying  warm 
in  large  quantities  as  is  usual ;  and  to  pre- 
vent insects  from  depositing  their  eggs 
Which  may  breed  the  worms  often  found 
in  good  flour.  And  further  to  complete 
this  principle  so  as  to  dry  the  meal  more 
effectually,  and  to  cause  the  flour  to  keep 
sweet  a  longer  space  of  time,  I  mean  to 
increase  the  heat  of  the  meal  as  it  falls 
ground  from  the  mill-stones  by  applica- 
tion of  heated  air,  that  is  to  say,  to  kiln- 
dry  the  meal  as  it  is  ground,  instead  of 
kiln-drying  the  grain  as  usual.  The  flour 
will  be  fairer  and  better  than  if  made 
from  kiln-dried  grain,  the  skin  of  which  is 
made  so  brittle  that  it  pulverizes  and  mix- 
es with  the  flour.  This  principle  I  apply 
by  various  machines  which  I  have  invent- 
ed, constructed  and  adapted  to  the  pur- 
poses hereafter  specified,  numbered  1,  2, 
3,  4,  5. 

My  second  principle  is  to  apply  the 
power  that  moves  the  mill  or  other  prin- 
cipal machine  to  work  my  machinery,  and 
by  them  to  perform  various  operations 
which  have  always  heretofore  been  per- 
formed by  manual  force,  and  thus  greatly 
to  lessen  the  expence  and  labour  of  at- 
tending mills  and  other  works. 

The  application  of  those  principles  in- 
cluding that  of  kiln -drying  the  meal  dur- 
ing the  process  of  the  manufacture  or 
otherwise,  to  the  improvement  of  the  pro- 
cess of  manufacturing  flour,  and  for  other 
purposes,  is  what  1  claim  as  my  invention 
and  improvement  in  the  art,  as  not  having 
been  known  or  used  before  my  discovery: 
knowing  well  that  the  principles  once  ap- 
plied by  one  set  of  machinery,  to  produce 
the  desired  effect,  others  may  be  contriv- 
ed and  variously  constructed  and  adapted 
to  produce  like  effects  in  the  application 
of  the  principles,  but  perhaps  none  to  pro- 
duce the  desired  effect  more  completely 
than  those  which  I  have  invented  and 
adapted  to  the  purposes,  and  which  are 
hereinafter  specified. 

No.  1.  The  Elevator. — Its  use  is  to  ele- 
vate any  grain,  granulated  or  pulverized 


substances.  Its  use  in  the  manufacture  of 
flour  or  meal  is  to  elevate  the  meal  from 
the  millstones  in  small  separate  parcels, 
and  to  let  it  fall  through  the  air  on  the 
cooling  floor,  as  fast  as  it  is  ground.  It 
consists  of  an  endless  strap,  rope  or  chain, 
with  a  number  of  small  buckets  attached 
thereto,  set  to  revolve  round  two  pulleys, 
one  at  the  lowest,  and  the  other  at  the 
highest  point  between  which  the  sub- 
stance is  to  be  raised.  These  buckets  fill 
as  they  turn  under  the  lower,  and  empty 
themselves  as  they  turn  over  the  upper 
pulley.  The  whole  is  inclosed  by  cases 
of  boards  to  prevent  waste. 

No.  2.  The  Conveyer. — Its  use  is  to  con- 
vey any  grain,  granulated  or  pulverized 
substances  in  a  horizontal,  ascending  or 
descending  direction.  Its  use  in  the  pro- 
cess of  the  art  of  manufacturing  flour,  is 
to  convey  the  meal  from  the  millstones,  as 
it  is  ground,  to  the  elevator  to  be  raised 
and  to  keep  the  meal  in  constant  motion, 
exposing  it  to  the  action  of  the  air,  also  in 
some  cases  to  convey  the  meal  from  the 
elevator  to  the  bolting  hopper,  and  to  cool 
and  dry  it  fit  for  bolting,  instead  of  the  hop- 
per boy,  No.  3  ;  also  to  mix  the  flour  after 
it  is  bolted ;  also  to  convey  the  grain  from 
one  machine  to  another,  and  in  this  opera- 
tion to  rub  the  impurities  off  the  grain.  It 
consists  of  an  endless  screw,  set  to  revolve 
in  a  tube  or  section  of  a  tube,  receiving 
the  substance  to  be  moved,  at  one  end, 
and  delivering  it  at  the  other  end ;  but, 
for  the  purpose  of  conveying  flour  or  meal, 
I  construct  it  as  follows :  Instead  of  mak- 
ing it  a  continued  spiral,  which  forms  the 
endless  screw,  I  set  small  boards  called 
flights,  at  an  angle  crossing  the  spiral  line; 
these  flights  operate  like  so  many  ploughs 
following  each  other,  moving  the  meal 
from  one  end  of  the  tube  to  the  other 
with  a  continued  motion,  turning  and  ex- 
posing it  to  the  action  of  the  air  to  be 
cooled  and  dried.  Sometimes  1  set  some 
of  the  flights  to  move  broadside  foremast 
to  lift  the  meal  from  one  side  to  fall  on 
the  other  to  expose  it  to  the  air  more  ef- 
fectually. 

No.  3.  The  Hopper  Boy.— Its  use  is  to 
spread  any  grain,  granulated  or  pulver- 
ized substances,  over  a  floor  or  even  sur- 
face, to  stir  it  and  expose  it  to  the  air  to 
dry  and  cool  it,  when  necessary  ;  and  at 
the  same  time  to  gather  it  from  the  cir- 
cumference of  the  circle  it  describes,  to, 
or  near  the  centre,  or  to  spread  it  from 
the  centre  to  the  circ  umference,  and  leave 
it  in  the  place  where  we  wish  it  to  be  de- 
livered, when  sufficiently  operated  on.  Its 
use  in  the  process  of  manufacturing  flour 
is  to  spread  the  meal  as  fast  as  it  falls 
from  the  elevator  over  the  cooling  floor. 


MFC 


MEC 


on  the  area  of  a  circle  of  from  eight  to  six- 
teen feet  more  or  less  in  diameter,  accord- 
ing- to  the  work  of  the  mill,  to  stir  and 
turn  it  continually,  and  to  expose  it  to  the 
action  of  the  air  to  be  dried  and  cooled, 
and  to  gather  it  into  the  bolting  hoppers, 
and  to  attend  the  same  regularly.  It  con- 
sists of  an  upright  shaft  made  round  at 
the  lower  end,  about  two-thirds  of  its 
lengtl),  and  set  to  revolve  on  a  pivot  in 
the'  centre  of  the  cooling  floor ;  through 
this  shaft,  say  five  feet  from  the  floor,  is 
put  a  piece  called  the  leader,  and  the 
lower  end  of  the  shaft  passes  very  loose- 
ly through  a  round  hole  in  the  centre  of 
another  piece  called  the  arms,  say  from 
eight  to  sixteen  feet  in  length,  this  lust 
piece  revolving  horizontally,  describes  the 
circle  of  the  cooling  floor,  and  is  led 
round  by  a  cord,  the  two  ends  of  which 
are  attached  to  the  two  ends  of  the  ai  ms, 
and  passing  through  a  hole  at  each  end 
of  the  leader,  so  that  the  cord  will  reeve 
to  pull  each  end  of  the  arms  equal!) 
The  weight  of  the  arms  is  nearly  ba  lanced 
by  a  weight  hung  to  a  cord,  which  is  at- 
tached to  the  arms,  and  passes  over  a  ptu- 
ley  near  to  the  upper  end  of  the  upright 
shaft,  to  cause  the  arms  to  play  lightly, 
pressing  with  only  part  of  their  weight  on 
the  meal  that  may  be  under  it.  The  fore- 
most edges  of  the  arms  are  sloped  up- 
wards, to  cause  them  to  rise  over  and 
keep  on  the  surface  of  the  meal  as  the 
quantity  increases  :  and  if  it  be  used  se- 
parately and  unconnected  with  the  eleva- 
tor, the  meal  may  be  thrown  with  shovels 
within  its  reach,  while  in  motion,  and  it 
Tvill  spread  it  level,  and  rise  over  it,  until 
the  heap  be  four  feet  high  or  more,  which 
it  will  gather  into  the  hoppers,  always  tak- 
ing from  the  surface,  after  turning  it  to 
the  air  a  great  number  of  times.  The  un- 
derside of  these  arms  are  set  with  little  in- 
clining boards  called  flights,  about  four 
inches  apart  next  the  centre,  and  gradu 
ally  closing  to  about  two  inches  next  the 
extremities,  the  flights  of  the  one  arm  to 
track  between  those  of  the  other,  they 
operate  like  ploughs,  and  at  every  revolu- 
tion of  the  machine,  they  give  the  meal 
two  turns  towards  the  centre  of  the  circle, 
near  to  which  are  generally  the  bolting 
hoppers.  At  each  extremity  of  the  arms 
there  is  a  little  board  attached  to  the  hind- 
most edge  of  the  arm  to  move  side  fore- 
most; these  are  called  sweepers,  their 
use  is  to  receive  the  meal  as  it  fads  from 
the  elevator,  and  trail  it  round  the  circle 
described  by  the  arms,  that  the  flights 
may  gather  it  towards  the  centre  from 
every  part  of  the  circle  ,  without  these, 
this  machine  would  not  spread  the  meal 
over  the  whole  area  of  the  circle  describ- 


ed by  the  arms.  Other  sweepers  are  at- 
tached to  that  pan  of  the  ai  ms  which 
pass  over  the  bolting  hoppers  to  sweep 
the  meal  into  them. 

But  if  the  boiling  hoppers  be  near  a 
wall  and  not  in  the  centre  of  the  cooling 
floor,  then  in  this  case  the  extremity  of 
the  aims  are  made  to  pass  over  them,  and 
the  meal  irom  the  elevator  let  fall  near  the 
centre  of  the  machine,  and  the  flights  are 
revtrsedto  turn  the  meal  from  the  centre 
towards  the  circumference,  and  the 
sweepers  will  sweep  it  into  the  hoppers. 
Thus  this  machine  receives  the  meal  as  it 
talis  from  fhc  eievator  on  the  cooling 
floor,  spreads  it  over  the  floor,  turns  it 
twice  over  at  every  revolution,  stirs  and 
keeps  it  in  continual  motion,  and  gathers 
it  ai  the  same  operation  into  the  bolting 
hoppers,  and  attends  them  regularly.  If 
the  jolting  reels  are  stopped,  this  machine 
spreads  the  meal  and  rises  over  it,  receiv- 
ing under  it  from  one,  two  to  three  hun- 
dred bushels  of  meai,  until  the  bolts  are 
bet  in  motion  again,  when  it  gathers  the 
meal  into  the  hoppers,  and  as  the  heap  di- 
minishes, it  follows  it  down  until  all  is 
bulted  1  claim  as  my  invention,  the  pe- 
culiar properties  or  principles  which  this 
machine  possesses,  viz..  the  spreading, 
turning  and  gathering  the  meal  at  one 
operation,  and  the  rising  and  lowering  of 
of  its  arms  by  its  motion  to  accommodate 
itself  to  any  quantity  of  meal  it  has  to  ope- 
rate on. 

No.  4.  7  he  Brill. — Its  use  is  to  move 
any  grain,  granulated  or  pulverized  sub- 
stance from  one  place  to  another :  it  con- 
sists, like  the  elevator,  of  an  endless  strap, 
rope  or  chain,  &c  with  little  rakes  instead 
of  buckets  (the  whole  cased  with  boards 
to  prevent  waste)  revolving  round  two 
pulleys  or  rollers.  Its  use  in  the  process 
of  the  manufacture  of  flour  is  to  draw  or 
rake  the  grain  or  meal  from  one  part  of 
the  mill  to  another.  It  receives  it  at  one 
pulley,  and  delivers  it  at  the  other,  in  a 
horizontal,  ascending  or  descending  di- 
rection, and  in  some  cases  may  be  more 
conveniently  applied  for  that  purpose  than, 
the  conveyer.  I  claim  the  exclusive  right 
to  the  principles  and  to  all  the  machines 
above  specified,  and  for  all  the  uses  and 
purposes  specified,  as  not  having  been 
heretofore  known  or  used  before  I  discov- 
ered them.  They  may  all  be  united  and 
combined  in  one  flour  mill  to  produce  my 
improvement  on  the  art  of  manufacturing 
flour  complete,  or  they  may  each  be  used 
separately  for  any  of  the  purposes  speci- 
fied and  allotted  to  them  or  to  produce  my 
improvement  in  part,  according  to  the 
circumstances  of  the  case. 

No.  5.  The  Kiln- Brier —To  kiln-dry  the 


MEC 

meal  after  it  is  ground,  and  during-  the 
operation  of  the  process  of  manufacturing 
flour,  I  take  a  close  stove  of  any  common 
form,  and  inclose  it  with  a  wall  made  of 
the  best  non-conductor  of  heat,  leaving  a 
small  space  between  the  stove  and  the 
wall,  to  admit  air  to  be  heated  in  its  pas- 
sage  through  this  space.    I  set  this  stove 
below  the  conveyor,  that  conveys  the 
meal  from  the  mill-stones,  as  ground  into 
the  elevator,  and  I  connect  the  space  be- 
tween the  stove  and  the  wall,  to  the  con- 
veyor tube,  by  a  pipe  entering  near  the 
elevator,  and  I  cover  the  conveyor  close, 
and  set  a  tube  to  rise  from  the  end  of  the 
conveyor  tube,  near  the  mill-stones,  for 
the  heated  air  to  ascend  and  escape  as  up 
a  chimney.    I  make  fire  in  the  stove  and 
admit  air  at  the  bottom  of  the  space  be- 
tween it  and  the  wall  round  it,  to  be  heat- 
ed and  pass  along  the  conveyor  tube, 
meeting  the  meal  which  will  he  heated  by 
the  hot  air,  and  the  superfluous  moisture 
will  be  more  powerfully  repelled  and 
thrown  off  and  the  meal  will  be  dried  and 
cooled  as  it  passes  through  the  operation 
of  the  elevator  and  hopperboy.    The  flour 
Will  be  fairer  than  if  the  grain  had  been 
kiln-dried,  and  it  will  keep  longer  sweet 
than  flour  not  kiln-dried     I  set  all  my 
machines  in  motion  by  the  common  means 
of  cog  and  round  tooth  and  pinion  straps, 
ropes,  or  chains,  well  known  to  every  mill- 
wright. 

Arrangement  and  connexion  of  the  se- 
veral machines,  so  as  to  apply  my  princi- 
ples to  produce  my  improvements  com- 
plete. 

I  fix  a  spout  through  the  wall  of  the 
mill  for  the  grain  to  be  emptied  into  from 
the  waggoner's  bag-,  to  run  into  a  box 
hung  at  the  end  of  a  scale  beam,  to  weigh 
a  waggon  load  at  a  draught.  From  this 
box  it  descends  into  the  grain  elevator, 
which  raises  it  to  a  granary  over  the  clean- 
ing machines,  and  as  it  passes  through 
them,  it  may  be  directed  into  the  same 
elevator  to  ascend,  to  be  cleaned  a  second 
time,  and  then  descends  into  a  granary, 
over  the  hopper  of  the  millstones  to  sup- 
ply them  regularly,  and  as  ground  it  falls 
from  the  several  pair  of  millstones  into 
the  conveyers,  where  it  is  dried  by  the 
heated  air  of  the  kiln-drier,  and  is  con- 
veyed into  the  meal  elevator,  to  be  raised 
and  dropped  on  the  cooling  floor  Within 
reach  of  the  hopper-boy,  which  receives 
and  spreads  it  over  the  whole  area  of  the 
circle  which  it  describes,  stirring  and 
turning  it  continually,  and  gathering  it  in- 
to the  bolting  hoppers  which  it  attends 
regularly.  That  part  of  the  flour  which 
is  not  sufficiently  bolted  by  the  first  ope- 
ration, is  conveyed  by  a  conveyer  or  drill 
into  the  elevator,  to  ascend  with  the  meai 


MEC 

to  be  bolted  over  again,  and  that  pari  of 
the  meal  which  has  not  been  sufficiently 
ground  at  the  first  operation  is  conveyed 
by  a  conveyer  or  drill,  and  let  run  into 
the  eye  of  the  millstone  to  be  ground  over. 

Thus  the  whole  of  the  operations  which 
used  to  be  performed  by  manual  labour 
is,  from  the  time  the  wheat  is  emptied 
from  the  waggoner's  bag,  or  from  the 
ship's  measure,  until  it  enters  the  bolts 
and  the  manufacture  be  completed  in  the 
most  perfect  manner,  performed  by  the 
machinery  moved  by  the  power  which 
moves  the  mill,  and  this  machinery  keeps 
the  meal  in  constant  motion  during  the 
whole  process,  drying  and  cooling  it  more 
completely,  avoiding  all  danger  from  fer- 
mentation, and  preventing  insects  from 
depositing  their  eggs,  and  performing  all 
the  operations  of  grinding  and  bolting,  to 
much  greater  perfection,  making  the 
greatest  possible  quantity  of  the  best  qua- 
lity of  flour  out  of  the  grain,  saving  much 
time  and  labour  and  expenceto  the  miller, 
and  preventing  much  from  being  wasted 
by  the  motion  of  the  machines  being  so 
slow  as  to  cause  none  of  the  flour  to  rise 
in  form  of  dust  and  be  carried  away  by  the 
air,  and  the  cases  of  the  machines  being 
made  close  prevents  any  from  being  lost." 

The  following  letter  may  also  be  no- 
ticed :— 

The  principles  of  these  improvements 
consist, 

f.  In  the  subdivision  of  the  grain,  or 
any  granulated  or  pulverized  substance ; 
in  elevating  and  conveying  them  from 
place  to  place  in  small  separate  parcels  ; 
in  spreading,  stirring,  turning  and  gather- 
ing them  by  regular  and  constant  motion, 
so  as  to  subject  them  to  artificial  heat,  the 
full  action  of  the  air  to  cool  and  dry  the 
same  when  necessary,  to  avoid  danger 
from  fermentation,  and  to  prevent  insects 
from  depositing  their  eggs  during  the  ope- 
ration of  the  manufacture. 

2.  In  the  application  of  the  power  which 
moves  the  mill  or  other  principal  machine, 
to  work  any  machinery  which  may  be  used 
to  apply  the  said  principles,  or  to  perform 
the  said  operations  by  constant  motion 
and  continued  rotation,  to  save  expence 
and  labour. 

The  machinery  by  him  already  invent- 
ed and  used  for  applying  the  above  prin- 
ciples, consists  of  an  improved  elevator,  an 
improved  conveyor,  an  improved  hopper- 
boy,  an  improved  drill,  and  an  improved 
kiln-drier. 

The  method  for  setting  out  a  spur-xvheel 
and  walloxuer. — Draw  the  pitch  lines  Alt 
B1,  A2,  2B  ;  (Plate  V.  Fig.  1.)  then  di- 
vide them  into  the  number  of  teeth  or 
cogs  required,  as  a  b  c. 
Divide  one  of  these  distances,  as  be, 


MEG 


MEC 


into  seven  equal  parts,  as  1,  2,  3,  4,  5,  6, 
7  ;  three  parts  allow  for  the  thickness  of 
the  cogs,  as  1,  2,  3,  in  the  cog  a,  and  four 
fur  the  thickness  of  the  stave  of  the  wal- 
lower. One  reason  for  allowing  three  parts 
for  the  cog,  and  four  tor  the  stave  is,  the 
wallower  is  in  general  of  less  diameter 
than  the  wheel,  therefore  subject  to  more 
wear,  in  proportion  of  the  number  of  cogs 
to  the  number  of  staves;  but  if  there  is 
the  same  number  of  staves  as  of  cogs,  they 
may  be  of  equal  thickness,  as  1,  2,  3,  4, 
in  the  stave  m,  (Fig-.  2  ;)  the  height  of  the 
cog  is  equal  to  tour  parts;  then  divide  its 
height  into  five  equal  parts,  as  1,  2,  3,  4, 
5,  in  the  cog  C  ;  allow  three  for  the  bot- 
tom to  the  pinch-line  of  the  cog ;  the  other 
two  parts  tor  epicycloid,  so  as  to  fit  and 
bear  on  the  stave  equally.  The  mill- 
wrights in  .general,  put  the  point  of  a  pair 
of  compasses  in  the  dot  2  of  the  cog  a,  and 
strike  the  line  ds  e  ;  then  remove  the  point 
of  the  compasses  to  the  point  d,  and  strike 
the  curve  line  3  J\  which  they  account 
near  enough  the  figure  of  the  epicycloid. 

The  method  for  a  face-wheel  is  thus  : 
divide  the  pitch-line  AB  (Fig.  2.)  into  the 
number  of  cogs  intended,  as  ab  c  ;  divide 
the  distance  b  c,  into  seven  equal  parts  ; 
three  of  those  parts  allow  for  the  thick- 
ness of  the  cogs,  as  1,  2,  3,  in  the  cog  a, 
four  for  the  height,  and  four  for  the 
width,  as  d,  <?,  and  four  for  the  thickness 
of  the  stave  m ;  draw  a  line  through 
the  centre  of  the  cog,  as  the  line  AI, 
at  S  ;  and  on  the  point  5,  describe  the 
line  d  e ;  remove  the  compasses  to  the 
point  A,  and  draw  the  line  J  g,  which 
forms  the  shape  of  the  cog ;  then  shape 
the  cog  on  the  sides  to  a  cycloid,  as  d  e  fg 
(Eig.  1.)  But  this  method  of  setting  out 
the  shape  of  a  cog  is  variable,  according 
to  the  cycloid  in  different  diameters  of 
wheels. 

In  common  spur-nuts,  divide  the  pitch- 
line  A,  into  twice  as  many  equal  parts  as 
you  intend  teeth,  as  a  6  c  de,  (Fig\  3.)  with 
a  pair  of  compasses  opened  to  half  the  dis- 
tance of  any  of  those  divisions,  from  the 
points  a  1,  c  3,  e  5,  draw  the  semicircles 
a,  c,  and  e,  which  will  form  the  ends  of 
the  teeth.  From  the  points  2,  4,  and  6, 
draw  the  semicircles  g  h  i,  which  will  form 
the  hollow  curves  for  the  spaces  ;  but  if 
the  ends  of  the  teeth  were  epicycloids  in- 
stead of  semicircles,  they  would  act  much 
better. 

Bevel-geer  — Instead  of  spur-wheels  and 
truddles,  bevelled-wheels,  commonly  call- 
ed bevel-geer,  are  now  generally  used — - 
Their  principle  consists  in  two  cones  roll- 
ing on  the  surface  of  each  other,  as  the 
~one  A  and  B  revolving  on  their  centres 


ab,ac;  (Fig.  4.)  if  their  bases  are  equal, 
they  will  perform  their  revolutions  in  one 
and  the  same  time,or  any  other  two  points, 
equally  distant  from  the  centre  cr,  as  d  1, 
d  2,  d  3,  &c.  will  revolve  in  the  same  time 
as / 1,/  2,f  3,  &c.  In  the  like  manner,  if 
the  cones  a  d  e,  be  twice  the  diameters  at 
the  base  d  e}  as  the  cones  afe  are,  then  if 
they  turn  about  their  centres  when  the 
cone  a  J'e  (Fig.  5  and  6)  has  made  one  re- 
volution, the  cone  a  d  e  will  have  made 
but  half  a  revolution  ;  or  when  a  fe,  has 
made  two  revolutions,*?  d  e  will  have  made 
but  one,  and  every  part  equally  distant 
from  the  centre  a,  as f  I,f2,f3,  &c.  will 
have  made  two  revolutions  to  e  1,  e  2,  e  3, 
&c.  and  if  the  cones  were  fluted,  or  had 
teeth  cut  in  them,  diverging  from  the  cen- 
tre a  to  the  base  d  c,e  f}  (Fig.  7.)  they 
would  then  become  bevel-geer.  The  teeth 
at  the  point  of  the  cone  being  small,  and 
of  little  use,  may  be  cut  off  at  E  and  F, 
(Fig.  7  and  8.)  where  the  upright  shaft 
a  b,  with  the  hevel-wheel,  c  d,  turns  the 
bevel-wheel  e  /with  its  shaft  bg,  and  the 
teeth  work  freely  into  each  other.  The 
teeth  may  be  made  of  any  dimension,  ac- 
cording to  the  strength  required;  and  this 
method  will  enable  them  to  overcome 
a  much  greater  resistance,  and  work 
smoother  than  a  face-wheel  and  wallower 
of  the  common  form  can  possibly  do ;  be- 
sides, it  is  of  great  use  to  convey  a  motion 
in  any  direction,  or  to  any  part  of  a  build- 
ing, with  the  least  trouble  and  friction. 

The  method  of  conveying  a  motion  in 
any  direction,  and  propoi  tioning  or  sharp- 
ening the  wheels  thereto,  is  as  follows  :  let 
the  line  a  b  represent  a  shaft  coming  from 
a  wheel ;  draw  the  line  c  d  to  intersect 
the  line  a  b,  (Fig.  9.)  in  the  direction  that 
the  motion  to  be  conveyed  is  intended, 
which  will  now  represent  a  shaft  to  the 
intended  motion. 

Again,  suppose  the  shaft  c  d  is  to  re- 
volve three  times,  whilst  the  shaft  a  b  re- 
volves once  ;  draw  the  parallel  line  i  i  at 
any  distance  not  too  great  (suppose  one 
foot  by  a  scale,)  then  draw  the  parallel 
line  k  k  at  three  feet  distance,  after  which, 
draw  the  dotted  line  iv  x,  through  the  in- 
tersection of  the  shafts  a  b  and  c  d,  and 
likewise  through  the  intersection  of  the 
parallel  lines  /'  i  and  k  l,  in  the  point  x 
and  7,  which  will  be  the  pitch-line  of  the 
two  bevel-wheels,  or  the  line  where  the 
teeth  of  the  two  wheels  act  on  each  other, 
as  may  be  seen  Fig.  10,  where  the  motion 
may  be  conveyed  in  any  direction. 

The  universal  joint,  as  represented  Fig. 
11,  may  be  applied  to  communicate  mo- 
tion instead  of  bevel  -geer,  where  the  speed 
is  to  be  continued  the  same,  and  where 


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MEC 


the  angle  does  not  exceed  50  or  40  de- 
grees, and  the  equality  of  motion  is  not 
regarded  ;  for  as  it  recedes  from  a  right 
line,  its  motion  becomes  more  irregular. 
This  joint  maybe  constructed  by  across, 
as  represented  in  the  figure  ;  or  with  four 
pins  fastened  at  right-angles  upon  the  cir- 
cumference of  a  hoop,  or  solid  ball.  It  is 
of  great  use  in  cotton  mills,  where  the 
tumbling  shafts  are  continued  to  a  great 
distance  from  the  moving  power.  But  by 
applying  this  joint,  the  shafts  may  be  cut 
into  convenient  lengths,  by  which  it  will 
be  enabled  to  overcome  greater  resist- 
ance. 


Further  ^Observations  on  Sundry  Parts  of 
Machinery. 

In  machinery,  where  la  rge  weights  are  I 
to  be  raised,  such  as  fulling-mills,  mills 
for  pounding,  &c  or  where  large  pistons 
are  to  be  elevated  by  the  arms  of  levers, 
it  is  of  the  greatest  consequence  that  the 
power  should  raise  the  weight  with  a  uni- 
form force  and  velocity  ;  and  this  can  be 
effected  only  by  giving  a  proper  form  to 
the  wipers  or  communicating  parts.  A 
certain  class  of  mechanics  generally  ex- 
cuse themselves  for  not  attending  to  the 
proper  form  of  the  teeth  of  wheels,  by 
alleging  that  the  scientific  form  differs  but 
little  from  theirs,  and  that  teeth,  however 
badly  formed,  will  in  the  course  of  time, 
work  into  their  proper  shape.  This  ex- 
cuse, however,  will  not  apologize  for  their 
negligence  in  the  present  case.  The  scien- 
tific form  of  the  wipers  or  stampers,  and 
the  arms  of  levers  are  so  widely  different 
from  the  form  which  is  generally  assigned 
them,  as  to  increase  very  much  the  per- 
formance of  the  machine,  and  preserve 
its  parts  from  the  injury  which  is  always 
occasioned  by  the  w  ant  of  a  uniform  mo- 
tion. 

Now  there  are  two  cases  in  which  this 
uniformity  of  motion  may  be  required,  and 
each  of  these  demands  a  different  form  for 
the  communicating  parts.  1.  When  the 
weight  is  to  be  raised  perpendicularly,  as 
the  piston  of  a  pump,  &.c.  2.  When  the 
weight  to  be  raised  or  depressed  moves 
upon  a  centre,  and  rises  or  falls  in  the 
arch  of  a  circle,  such  as  the  sledge-ham- 
mer in  a  forge,  the  stampers  in  a  fulling- 
mill,  &c. 

t  In  Fig.  4,  of  Plate  Till,  let  AB  be 
an  axis  driven  by  a  water-wheel  or  any 
other  power,  at  right  angles  to  which  is 
fixed  the  bar  nnm,  on  whose  extremities 
the  wipers  mn  inn  are  fastened.  The 
wiper  mn  acting  upon  the  arm  FE,  raises 
the  piston  or  weight  EF  to  the  required 


height.  The  piston  then  falls,  and  is  again 
raised  by  the  lower  wiper.  It  often  hap- 
pens that  two  or  three  pistons  are  to  be 
employed,  and  in  this  case  the  axis  AB 
must  carry  four  or  six  wipers,  which 
should  be  so  distributed  upon  its  circum- 
ference that  when  one  piston  is  about  to 
fall,  the  other  may  begin  to  rise.  Now, 
in  order  that  these  pistons  may  be  raised 
with  a  uniform  motion,  the  form  of  the 
wiper  mn  must  be  the  evolute  of  a  circle 
whose  diameter  is  mm;  or,  in  other  words, 
it  must  be  an  epicycloid,  formed  by  a  ge- 
nerating circle,  whose  centre  is  infinitely 
distant,  rolling  upon  the  convex  circum- 
ference of  another  circle  whose  diameter 
is  nun  But  as  a  small  roller  P,  is  fre- 
quently fixed  to  the  extremity  of  the  arm 
E,  to  diminish  the  friction  of  the  working 
parts,  we  must  draw  a  curve  within  the 
above-mentioned  involute,  and  parallel 
to  it,  the  distance  between  them  being 
equal  to  the  radius  of  the  roller;  and 
this  new  curve  will  be  the  proper  form 
for  the  wiper  mn  when  a  roller  is  em- 
ployed. 

The  piston  may  also  be  raised  or  de  - 
pressed uniformly,  by  giving  a  proper 
curvature  to  the  arm  PE,  and  fixing  the 
rolierupon  the  extremities  of  the  bar?»m. 
Thus  in  Fig.  4,  let  CD  be  an  axis,  moved 
by  any  power,  in  which  are  fixe  d  the  arms 
DH,  MR,  having  rollers  Hit  at  their  ex- 
tremities, which  act  upon  the  curved  arm 
op.  When  the  piston  EF  is  raised  to  the 
proper  height  by  the  action  of  the  roller 
H  upon  op,  it  then  falls,  and  is  again  ele- 
vated by  the  arm  M.  In  order  that  its 
motion  may  be  uniform,  the  arm  op  must 
be  part  of  a  cycloid,  the  radius  of  whose 
generating  circle  is  equal  to  the  length  of 
the  arm  DH,  reckoning  from  its  extremi- 
ty Ii,or  the  centre  of  the  roller,  to  the  cen- 
tre of  the  axle  DC.  But  when  a  roller  is 
fixed  upon  the  extremity  H,  we  must  draw 
a  curve  parallel  to  the  cycloid,  and  with- 
out it,  at  the  distance  of  the  roller's  semi- 
diameter  ;  and  this  curve  will  be  the  pro- 
per form  for  the  arm  op  It  is  evident  that 
when  this  mode  of  raising  the  piston  is 
adopted,  the  a>m  DH  must  be  bent  as  in 
the  figure,  otherwise  the  extremity  p 
would  prevent  the  roller  H,  from  acting 
upon  the  arm  op. 

In  Fig.  6.  we  have  another  method  of 
raising  a  weight  perpendicularly  with  a 
uniform  motion.  Let  AH  be  a  wheel  mov- 
ed by  any  power  which  is  sufficient  to 
raise"  the"  weight  MN  by  its  extremity  O, 
from  O  to  e,  in  the  same  time  that  the 
wheel  moves  round  one-fourth  of  its  cir- 
cumference, it  is  required  to  fix  upon  its 
rim  a  wing  OBCDEH  which  shall  produce 
this  effect  with  a  uniform  effort.  Divide 


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the  quadrant  OH  into  any  number  of  equal 
parts  Om  mn,  &c.  the  more  the  better, 
and  oeinto  the  same  number  ob,  be,  cd,  &c. 
and  through  the  points  m,  n,  p,  H,  draw 
the  indefinite  lines  AB,  AC,  AD,  AE,  and 
Hhke  AD  equal  to  Ab,  AC  to  Ac,  AD  to 
Ad,  and  AE  to  Ae ;  then  through  the 
points  U,B,C,D,E,  draw  the  curve  OBCDE 
which  is  a  portion  of  the  spiral  of  Ar- 
chimedes, and  will  be  the  proper  form  for 
the  wiper  or  wing-  OFI B.  It  is  evident  that 
when  the  point  m  has  arrived  at  O,  the 
extremity  of  the  weig-ht  will  have  arrived 
at  b ;  because  AB  is  equal  to  Ab,  and  for 
the  same  reason  when  the  points  n,  p,  II 
have  successively  arrived  at  O,  the  extre- 
mity of  the  weight  will  have  arrived  at  the 
corresponding-  points  c,  d,  e.  The  motion 
therefore  will  be  uniform,  because  the 
space  described  by  the  weight  is  propor- 
tional to  the  space  described  by  the  mov- 
ing power,  Ob  being  to  Oc  as  Om  to  0?i. 
If  it  be  required  to  raise  the  weight  MX 
with  an  accelerated  or  retarded  motion, 
we  have  only  to  divide  the  line  Oe,  accord- 
ing to  the  law  of  acceleration  or  retarda- 
tion, and  divide  the  curve  O  B  C  D  E  as 
before. 

2.  When  the  lever  moves  upon  a  centre, 
the  weight  will  rise  in  the  arch  of  a  circle, 
and  consequently  a  new  form  must  be 
given  to  the  wipers  or  wings.  The  cele- 
brated Deparcieux,  of  the  Academy  of 
Sciences  of  Paris,  has  given  an  ingenious 
and  simple  method  of  tracing  mechanical- 
ly the  curves  which  are  necessary  for  this 
purpose.  Though  this  method  was  pub- 
lished about  fifty  years  ago  in  the  Me- 
moirs of  the  Academy,  it  does  not  seem 
to  be  at  all  known  to  the  mechanics  of 
this  country.  We  shall  therefore  lay  it 
before  the  reader  in  as  abridged  and  sim- 
plified a  form  as  the  nature  of  the  subject 
will  permit  Let  AB,  Fig.  7,  be  a  lever 
lying  horizontally,  which  it  is  required  to 
raise  uniformly  through  the  arch  BC  into 
the  position  AC,  by  means  of  the  wheel 
BFH  furnished  with  the  wing  BNOP, 
which  acts  upon  the  extremity  C  of  the 
lever ;  and  let  it  be  required  to  raise  it 
through  BC  in  the  same  time  that  the 
wheel  BFH  moves  through  one  half  of  its 
circumference ;  that  is,  while  the  point 
M  moves  to  B  in  the  direction  MFB.  Di- 
vide the  chord  CB  into  any  number  of 
equal  parts,  the  more  the  better,  in  the 
points  1,  2,  3,  and  draw  the  lines  la,  2b, 
3c,  parallel  to  AB,  or  a  horizontal  line 
passing  through  the  point  B,  and  meeting 
the  arch  CB  in  the  points  a,  b,  c.  Draw 
the  lines  CD,  aD,  bD,  cD,  and  BD,  cutting 
the  circle  BFH  in  the  points  m,  n,  o,p 

Having  drawn  the  diameter  BM,  divide 
the  semicircle  BFM  into  as  many  equal 

VOL.  IT. 


parts  as  the  chord  CB,  in  the  points  q,  a,  u. 
Take  Bm  and  set  it  from  q  to  r  \  Take  Bn 
and  set  it  from  s  to  t :  Take  Bo  and  set  it 
from  u  to  v  :  and  lastly,  set  Bp  from  M  to 
E.  Through  the  points  r,  t,  v,  E,  draw 
the  indefinite  lines  DN,  DO,  DP,  DQ,  and 
make  DN  equal  to  Dc ;  DO  equal  to  Db  ; 
DP  equal  to  Da  ;  and  DQ  equal  to  DC. 
Then  through  the  points  Q,  P,  O,  N,  B, 
draw  the  spiral  B,  N,  O,  P,  Q,  which  will 
be  the  proper  form  for  the  wing  of  the 
wheel  when  it  moves  in  the  direction 
EMB. 

That  the  spiral  BNO,  will  raise  the  16- 
ver  AC,  with  a  uniform  motion  by  acting 
upon  its  extremity  c,  will  appear  from  the 
slightest  attention  to  the  construction  of 
the  figure.  It  is  evident,  that  when  the 
point  7  arrives  at  B,  the  point  r  will  be  ii» 
m,  because  Bm  is  equal  to  qr,  and  the 
point  N  will  be  at  c,  because  DN  is  equal 
to  Dc  ;  the  extremity  of  the  lever,  there- 
fore, will  be  found  in  the  point  c,  having 
moved  through  Be.  In  like  manner,  when 
the  point  s  has  arrived  at  B,  the  point  t 
will  be  at  n,  and  the  point  O  in  b,  where 
the  extremity  of  the  lever  will  now  be 
found ;  and  so  on  with  the  rest,  till  the 
point  M  has  arrived  at  B.  The  point  E 
will  then  be  in  p,  and  the  point  Q  in  C  ; 
so  that  the  lever  will  now  have  the  posi- 
tion AC,  having  moved  through  the  equal 
heights  B  c,  c  b,  b  a,  a  c,  in  the  same 
time  that  the  power  has  moved  through 
the  equal  spaces  q  B,  s  q,  us,  M  u.  The 
lever,  therefore,  has  been  raised  uniform- 
ly, the  ratio  between  the  velocity  of  the 
power,  and  that  of  the  weight,  remaining 
always  the  same. 

If  the  wheel  D  turns  in  a  contrary  di- 
rection, according  to  the  letters  MHB, 
we  must  divide  the  semicircle  BH  EM, 
into  as  many  equal  parts  as  the  chord  c  B, 
viz  in  the  points  c,  g,  h.  Then,  having 
set  the  arch  B  on,  from  e  to  d,  the  arch 
B  ii  from  g  to  f,  and  the  rest  in  a  similar 
manner,  draw  through  the  points  d,  f,  h9 
E,  the  indefinite  lines  DR,  DS,  DT,  DQ, 
make  DR  equal  to  Dc  ;  DS  equal  to  Db ; 
DT  equal  to  Da,  and  DQ  equal  to  DC  ; 
and  through  the  points  B,  R,  S,  T,  Q,  de- 
scribe the  spiral  BRSTQ,  which  will  be 
the  proper  form  for  the  wings,  when  the 
wheel  turns  in  the  direction  MEB.  For, 
when  the  point  e  arrives  at  B,  the  point  d 
will  be  in  on,  and  R  in  c,  whe>.  e  the  ex- 
tremity of  the  lever  will  now  be  found, 
having  moved  through  B  c  in  th  same 
time  that  the  power,  or  wheel,  has  moved 
through  the  division  e  B.  In  the  same 
manner  it  may  be  shown,  that  the  lever 
will  rise  through  the  equal  heights  c  b, 
b  a,  a  C,  in  the  same  time  that  the  power 
moves  through  the  corresponding  space4; 
M 


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f>  8>  6 » *»  ■  The  motion  of  the  lever, 
therefore,  and  also  that  of  the  power,  are 
always  uniform.  Of  all  the  positions  that 
can  be  given  to  the  point  B,  the  most  dis- 
advantageous are  those  which  are  nearest  I 
the  points  F,  H ;  and  the  most  advantage- 1 
disposition  is  when  the  chord  B  c  is  ver- ' 
tical,  and  passes,  when  prolonged,  through 
D,  the  centre  of  the  circle.  In  this  parti- 
cular case,  the  two  curves  have  equal 
bases,  though  they  differ  a  little  in  point 
of  curvature.  The  farther  that  the  centre 
A  is  distant,  the  nearer  do  these  curves 
resemble  each  other  ;  and  if  it  were  infi- 
nitely distant,  they  would  be  exactly  si- 
milar, and  would  be  the  spirals  of  Archi- 
medes, as  the  extremity  c  would  in  this 
case  rise  perpendicularly. 

The  intelligent  reader  will  easily  per- 
ceive, that  4,  6,  or  8  wings  may  be  placed 
upon  the  circumference  of  the  circle,  and 
may  be  formed  by  dividing  into  the  same 
number  of  equal  parts  as  the  chord  B  C, 
^,  ^  or  of  the  circumference,  instead 
of  the  semicircle  BFM. 

That  the  wing  BNO  may  not  act  upon 
any  part  of  the  lever  between  A  and  C, 
the  arm  AC  should  be  bent ;  and  that  the 
friction  may  be  diminished  as  much  as 
possible,  a  roller  should  be  fixed  upon  its 
extremity  C  When  a  roller  is  used,  how- 
ever, a  curve  must  always  be  drawn  pa- 
rallel to  the  spiral  described  according  to 
the  preceding  method,  the  distance  be- 
tween it  and  the  spiral  being  every  where 
equal  to  the  radius  of  the  roller. 

When  two  or  more  wings  are  placed 
upon  the  circumference  of  the  wheel,  it 
has  been  the  custom  of  practical  mecha- 
nics to  make  them  portions  of  an  ellipsis, 
whose  semi-transverse  axis  is  equal  to 
QD,  the  greatest  distance  of  the  curve 
from  the  centre  of  the  circle.  But  it  will 
appear  from  a  comparison  of  the  elliptical 
arch,  with  the  spiral  N,  that  it  will  not 
produce  a  uniform  motion.  If  it  should 
be  required  to  raise  the  lever  with  an  ac- 
celerated or  retarded  motion,  we  have 
only  to  divide  the  chord  BC,  according  to 
the  degree  of  retardation  or  acceleration 
required,  and  the  circle  into  the  same 
number  of  equal  parts  as  before,  and  then 
describe  the  curve  according  to  the  me- 
thod already  laid  down. 

As  it  is  frequently  more  convenient  to 
raise  or  depress  weights  by  the  extremity 
of  a  constant  radius,  furnished  with  a  rol- 
ler instead  of  wings  fixed  upon  the  peri- 
phery of  a  wheel ;  we  shall  now  proceed 
to  determine  the  curve  which  must  be 
given  to  the  arm  of  the  lever,  which  is  to 
be  raised  or  depressed,  in  order  that  this 
elevation  or  depression  may  be  effected 
with  an  uniform  motion. 


Let  AB,  Fig.  8,  be  a  lever,  which  it  is 
required  to  raise  uniformly  through  the 
arch  BC,  into  the  position  AC  by  means 
of  the  arm  or  constant  radius  DE,  mov- 
ing upon  D  as  a  centre,  in  the  same  time 
that  the  extremity  E  describes  the  arch 
E  e  F.  From  the  point  C  draw  C  H  at  right 
angles  to  AB,  and  divide  it  into  any  num- 
ber of  equal  parts,  suppose  three,  in  the 
points  1,  9  ;  und  through  the  points  1,  2, 
draw  la,  2b  parallel  to  the  horizontal 
line  AB,  catting  the  arch  CB  in  the  points 
a,  b,  through  which  draw  a  A,  b  A  Up- 
on D  as  a  centre,  with  the  dislancr  DE, 
describe  the  arch  E  i  e  F,  and  upon  A  as 
a  centre,  with  the  distance  AD.  describe 
the  arch  e  O  D,  cutting  the  arch  E/fF 
in  the  point  e.  Divide  the  archet  Ef  e.  and 
Fi  e,  each  into  the  same  number  of  equal 
parts  as  the  perpendicular  c  II,  in  die 
points  k,  t,  s,  vi,  and  through  these  points, 
about  the  centre  A,  describe  the  arches 
k  z,  i  g,  q  r,  vi  n.  Take  z  x  and  set  it  from 
k  to  /,  and  take  g  f  and  set  it  from  i  to  h. 
Take  r  q  also  and  set  it  from  §  to  t,  '«vd  set 
r.m  from  o  to  p,  and  d  c  from  e  to  O.  1  hen 
through  the  points  E,  /,  A,  O,  and  O,  t,p,  F, 
draw  the  two  curves  E  /  h  O,  and  O  t  p  F, 
which  will  be  the  proper  form  that  must 
be  given  to  the  arm  of  the  lever.  II  the 
handle  DE  move  from  E  towards  F,  the 
curve  EO  must  be  used,  but  if  in  the  con- 
trary direction,  we  must  employ  the  curve 
OF. 

It  is  evident  that  when  the  extremity 
E  of  the  handle  DE,  has  run  through  the 
arch  E  or  rather  E  /,  the  point  /  will  be 
in  I,  and  the  point  z  in  .v,  because  x  z  is 
equal  to  k  I,  and  the  lever  will  have  the 
position  Kb.  For  the  same  reason,  when 
the  extremity  E  of  the  handle  has  arrived 
at  z,  the  point  h  will  be  in  r,  and  the  point 
£-in  ft  and  the  lever  will  be  raised  to  the 
position  Art.  Thus  it  appears,  that  the 
motion  of  the  power  and  the  weight  are 
always  proportional.  When  a  roller  is 
fixed  at  E,  a  curve  parallel  to  EO,  or  OF, 
must  be  drawn  as  formerly. 

It  is  upon  these  principles  that  the  de- 
tent levers  of  clocks,  and  those  connected 
with  the  striking  part,  should  be  formed. 
In  every  machine,  indeed,  where  weights 
are  to  be  raised  or  depressed,  either  by 
variable  or  constant  levers,  its  perform- 
ance depends  much  on  the  proper  form  of 
the  communicating  parts. 

Hitherto  we  have  supposed,  that  the 
wheel  which  carries  the  wipers  or  wings, 
moves  in  the  same  plane  with  the  lever  or 
weight  to  be  raised.  Circumstances,  how- 
ever, often  occur,  which  render  it  neces 
sary  to  elevate  the  lever  by  means  of  a 
wheel  moving  at  right  angles  to  the  plane 
in  which  the  lever  moves  ;  and  when  this 


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method  is  adopted,  a  different  form  must 
be  given  to  the  wipers.  As  no  writer  on 
mechanics,  so  far  as  we  know,  has  treated 
upon  this  subject,  it  becomes  the  more 
necessary  to  supply  the  defect  by  a  few 
observations. 

Let  ABC,  Fig.  10,  Plate  VIII.  be  the  lever 
which  is  to  be  raised  round  the  axis  AD, 
by  the  action  of  the  wing  m  n  of  the  wheel 
1),  upon  the  roller  C,  fixed  at  the  extre- 
mity of  the  lever ;  it  is  required  to  find 
the  form  which  must  be  given  to  the  wi- 
per m  n.  It  is  evident  from  Fig.  1 1,  where 
GB  is  a  section  of  the  lever  and  roller, 
and  BA  the  arch  through  which  it  is  to  be 
raised,  that  the  breadth  of  the  wiper  must 
always  be  equal  to  m  n  or  r  B,  the  versed 
sine  of  the  arch  BA  through  which  the 
roller  moves,  so  that  the  extremity  n  of 
the  wiper  may  act  upon  the  roller  B  at  the 
commencement  of  the  motion,  and  the 
other  extremity  m  may  act  upon  the  roller 
A,  when  the  lever  arrives  at  the  required 
position  CA.  It  is  easy  to  perceive,  how- 
over,  that  if  the  acting  surface  m  n  of  the 
wiper  be  always  parallel  to  the  horizon, 
or  perpendicular  to  the  radii  of  the  wheel, 
or  the  plane  in  which  it  moves,  it  will  act 
disadvantageously,  except  at  the  com- 
mencement of  the  motion,  when  m  n  is 
parallel  to  CB.  For  when  m  n  has  arrived 
at  the  position  o  p,  the  extremity  o  will 
act  upon  the  roller  A,  but  in  such  an  ob- 
lique and  disadvantageous  manner,  that  it 
will  scarcely  have  any  power  to  turn  it 
upon  its  axis,  or  move  the  lever  round  the 
fulcrum  C  The  friction  of  the  roller  upon 
its  axis,  therefore,  will  increase,  and  the 
power  of  the  wiper  to  turn  the  lever  will 
diminish,  in  proportion  to  the  length  of 
the  arch  BA  ;  and  if  CA  arrive  at  a  verti- 
cal position,  the  power  of  the  wing  will  be 
solely  employed  in  wrenching  it  from  its 
fulcrum. 

Having  thus  described  the  different  me- 
thods of  raising  weights,  whether  perpen- 
dicularly, or  round  a  centre,  with  a  uni- 
form velocity  and  force :  it  would  be  un- 
necessary to  apply  the  principles  of  con- 
struction to  those  machines  which  are 
formed  for  the  elevation  of  weights.  The 
practical  mechanic  can  easily  do  this  for 
himself  There  is  one  case,  however, 
which  deserves  peculiar  attention,  because 
the  wipers,  formed  scientifically,  will  not 
produce  the  intended  effect.  Tins  happens 
in  the  large  sledge-hammer  which  is  em- 
ployed in  forges.  In  Fig.  3,  Plate  IX. 
BC  is  the  large  hammer  moved  round  A 
as  a  centre,  by  means  of  the  wiper  M\V 
acting  upon  its  extremity  AC,  or  upon  the 
roller  II.  The  hammer  must  be  tossed 
up  with  a  sudden  motion,  so  as  to  strike 
the  elastic  oaken  spring  E,  which,  being 


compressed,  drives  back  the  hammer  with 
great  force  upon  the  anvil  D.  Now,  if 
spiral  wipers,  constructed  according  to  the 
directions  already  given,  are  employed, 
the  hammer  will  indeed  be  raised  equably 
without  the  least  jolting,  but  it  will  rise 
no  higher  than  the  wiper  lifts  it,  and  will 
therefore  fall  merely  with  its  own  weight. 
But  if  the  wipers  are  constructed  in  the 
common  way,  and  the  hammer  elevated 
with  a  motion  greatly  accelerated,  it  will 
rise  much  higher  than  the  wiper  lifts  it ; 
it  will  impinge  against  the  oaken  beam  E, 
and  be  repelled  with  great  effect  against 
the  iron  on  the  anvil  D.  In  any  of  the 
preceding  constructions,  this  accelerated 
motion  may  be  produced,  merely  by  divid- 
ing BC  according  to  the  law  of  accelera- 
tion, and  proceeding  as  already  directed. 

A  <voater-mill,  invented  by  Dr.  Barker,  that 
has  neither  wheel  nor  trundle. 

This  machine  is  represented  by  Fig.  ,1 
of  Plate  IX.  in  which  A  is  a  pipe  or  chan- 
nel that  brings  water  to  the  upright  tube 
B.  The  wrater  runs  down  the  tube,  and 
thence  into  the  horizontal  trunk  C,  and 
runs  out  through  holes  at  d  and  e  near  the 
ends  of  the  trunk  on  the  contrary  sides 
thereof. 

The  upright  spindle  D  is  fixed  in  the 
bottom  of  the  trunk,  and  screwed  to  it 
below  by  the  nut  g;  and  is  fixed  into  the 
trunk  by  two  cross  bars  at  f :  so  that,  if 
the  tube  B  and  trunk  C  be  turned  round, 
the  spindle  D  will  be  turned  also. 

The  top  of  the  spindle  goes  square  in- 
to the  rynd  of  the  upper  mill-stone  //,  as 
in  common  mills ;  and,  as  the  trunk,  tube, 
and  spindle,  turn  round,  the  mill-stone  is 
turned  round  thereby.  The  lower,  or 
quiescent  mill-stone  is  represented  by  I ; 
and  K  is  the  floor  on  which  it  rests,  and 
wherein  is  the  hole  L  for  letting  the  meal 
run  through,  and  fall  down  into  a  trough, 
which  may  be  about  M-  The  hoop  or  case 
that  goes  round  the  mill-stone  rests  on  the 
floor  Kt  and  supports  the  hopper,  in  the 
common  way.  The  lower  end  of  the  spin- 
dle turns  in  a  hole  in  the  bridge -t  ree  G  1\ 
which  supports  the  mill-stone,  tube,  spin- 
dle, and  trunk.  This  tree  is  moveable  on 
a  pin  at  ht  and  its  other  end  is  supported 
by  an  iron  rod  .A*  fixed  into  it,  the  top  of 
the  rod  going  through  the  fixed  bracket 
O,  and  having  a  screw-nut  o  upon  it, 
above  the  bracket.  By  turning  this  nut 
forward  or  backward,  the  mill-stone  is 
raised  or  lowered  at  pleasure. 

While  the  tube  B  is  kept  full  of  water 
from  the  pipe  A,  and  the  water  continues 
to  run  out  from  the  ends  of  the  trunk, 
the  upper  mill-stone  H,  together  with  the 


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trunk,  tube,  and  spindle,  turns  round. 
But,  if  the  holes  in  the  trunk  were  stop- 
ped, no  motion  would  ensue ;  even  though 
the  trunk  and  tube  were  full  of  water  For, 

If  there  were  no  hole  in  the  trunk,  the 
pressure  of  the  water  would  be  equal 
against  all  parts  of  its  sides  within.  But, 
when  the  water  has  free  egress  through 
the  holes,  its  pressure  there  is  entirely  re- 
moved :  and  the  pressure  against  the 
parts  of  the  sides  which  are  opposite  to 
the  holes,  turns  the  machine. 

On  horizontal  mills.— Although  ho- 
rizontal water-wheels  are  very  common 
on  the  continent,  and  are  strongly  recom- 
mended to  our  notice  by  the  simplicity  of 
their  construction,  yet  they  have  almost 
never  been  erected  in  England,  and 
therefore  are  not-  described  in  any  of  our 
treatises  on  practical  mechanics.  In  or- 
der to  supply  this  "defect,  and  recommend 
them  to  the  attention  of  the  mill-wright, 
we  shall  give  a  brief  account  of  their  the- 
ory and  construction.  In  Fig.  1,  of  Plate 
X.  we  have  a  representation  of  one  of 
these  mills.  J  B  is  the  large  water-wheel 
which  moves  horizontally  upon  its  arbor 
CD  This  arbor  passes  through  the  im- 
moveable mill-stone  E  F  at  JD,  and,  being 
fixed  to  the  upper  one  G  H,  carries  it  once 
round  for  every  revolution  of  the  great 
wheel.  N  is  the  hopper,  and  I  the  mill- 
shoe,  the  rest  of  the  construction  being 
the  same  as  in  vertical  corn-mills. 

The  mill-course  is  constructed  in  the 
same  manner  for  horizontal  as  for  vertical 
wheels,  with  this  difference  only,  that  in- 
stead of  being  rectilineal,  it  must  be  cir- 
cular, and  concentric  with  the  rim  of  the 
wheel,  sufficient  room  being  left  between 
it  and  the  tips  of  the  float-boards  for  the 
play  of  the  wheel. 

The  equipage  of  the  millstone  of  a  ho- 
rizontal mill  (which  comprehends  the 
millstone,  the  water-wheel,  and  its  arbor) 
may  be  found  by  multiplying  the  product 
of  the  100th  part  of  the  expense  of  the 
water  in  cubic  feet,  and  the  relative  fail, 
by  5078,  and  the  product  will  be  the 
weight  of  the  equipage  in  pounds  avoir- 
dupois. 

The  mean  radius  of  the  wheel  A  B  is 
to  be  determined  by  multiplying  the  pro- 


duct of  the  relative  fall,  and  the  square 
root  of  the  expense  of  water  in  a  second 
by  0.062. 

What  has  been  said  respecting  the 
number,  position,  and  form  of  the  float- 
boards  of  vertical  wheels,  may  be  applied 
also  to  horizontal  ones.  In  tile  latter,  how- 
ever, the  float-boards  must  be  inclined, 
not  only  to  the  radius,  but  also  to  the 
plane  of  the  wheel,  in  the  same  angle  in 
which  they  are  inclined  to  the  radius,  so 
that  the  lowest  and  the  outermost  sides  of 
the  float-boards  may  be  farthest  up  the 
stream. 

Since  the  millstone  of  horizontal  mills 
performs  the  same  number  of  revolutions 
as  the  water-wheel ;  and  since  a  millstone 
five  feet  in  diameter  should  never  make 
less  than  48  turns  in  a  minute,  the  wheel 
must  perform  the  same  number  of  revo- 
lutions in  the  same  time ;  and  in  order 
that  the  effect  may  be  a  maximum,  or  the 
greatest  possible,  the  velocity  of  the  cur- 
rent must  be  double  that  of  the  wheel. 
Suppose  the  millstone,  for  example,  to  be 
five  feet  diameter,  and  the  water-wheel 
six  feet,  it  is  evident  that  the  millstone 
and  wheel  must  at  least  revolve  48  times 
in  a  minute ;  and  since  the  circumference 
of  the  wheel  is  18.8  feet,  the  float-boards 
will  move  through  that  space  in  the  48th 
part  of  a  minute,  that  is,  nearly  at  the  rate 
of  15  feet  per  second,  which  being  dou- 
bled, makes  the  velocity  of  the  water  30 
feet,  answering  to  a  fall  of  14  feet.  But 
if  the  given  fall  of  water  be  less  than  14 
feet,  we  may  procure  the  same  velocity  to 
the  millstone  by  diminishing  the  diameter 
of  the  wheel.  If  the  wheel,  for  instance, 
be  only  five  feet  diameter,  its  circumfer- 
ence will  be  15.7  feet,  and  its  floats  will 
move  at  the  rate  of  12.56  feet  in  a  second, 
the  double  of  which  is  25.12  feet  per  se- 
cond, which  answers  to  a  head  of  water 
less  than  ten  feet  high.  As  the  diameter 
of  the  water-wheel,  however,  should  ne- 
ver be  less  than  seven  times  the  breadth 
of  the  mill-course  at  K,  there  will  be  a 
certain  height  of  the  fall  beneath  which* 
we  cannot  employ  horizontal  wheels,  with- 
out making  the  millstone  revolve  too 
slowly.  This  height  will  be  found  by  the 
following  tattle. 


When  the  natural  depth  of  the  water 
at  the  bottom  of  the  fall  is  to  the 
breadth  of  -  the  mill-course  at  the 
same  place,  as 

3  to  1 

2  to  1 

1  to  1 

Equal. 

h  to  1 

-itol 

The  relative  fall  beneath  which  we 
cannot  employ  horizontal  mills,  will 
be 

7.314 

8.602 

11.350 

14.976 

17-613 

ft.  dec 

ft.  dec 

ft.  dec 

ft.  dec 

ft.  dec! 

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Thus  if  the  natural  depth  of  the  water  at 
A",  be  three  times  the  width  of  the  mill- 
course  at  the  same  place,  the  relative  fall 
beneath  which  we  cannot  employ  a  hori- 
zontal wheel  will  be  7.314  feet.  Since  the 
depth  of  the  water  is  so  great  in  this  case, 
a  great  quantity  of  it  will  be  discharged 
in  a  second,  and  therefore  it  requires  a 
less  velocity,  or  a  less  height  of  the  fall, 
to  impel  the  wheel ;  whereas,  if  the  depth 
of  the  water  had  been  only  one  third  of 
the  width  of  the  mill-course,  such  a  small 
quantity  would  be  discharged  in  a  se- 
cond that  we  must  make  up  for  the  want 
of  water  by  giving  a  greater  velocity  to 
what  u  e  have,  or  by  making  the  height  of 
the  fall  1?  613  feet. 

In  order  to  find  the  radius  of  the  mill- 
stone in  horizontal  mills,  multiply  the  ex- 
pense of  water  in  cubic  feet  in  a  second, 
by  the  relative  fall ;  extract  the  square 
root  of  the  product,  and  multiply  this  root 
by  0.267,  the  product  will  be  the  radius  of 
the  millstone  in  feet. 

The  quantity  of  meal  ground  in  an  hour 
may  be  found  by  the  rules  already  given 
for  vertical  mills,  or  by  multiplying  the 
product  of  the  expense  of  water  and  the 
relative  fall,  by  456  lb.  and  the  result  will 
be  the  quantity  required. 

The  thickness  of  the  millstone  at  the 
centre  and  circumference,  and  the  thick- 
ness of  the  arbor  and  pivots  may  be  de- 
termined by  the  rules  already  laid  down 
for  vertical  mills. 

In  horizontal  wheels,  the  mill-course  is 
sometimes  differently  constructed.  In- 
stead of  the  water  assuming  a  horizontal 
direction  before  it  strikes  the  wheel,  as  in 
the  case  of  undershot-mills,  the  floatboard 
is  so  inclined  as  to  receive  the  impulse 
perpendicularly,  and  in  the  direction  of 
the  declivity  of  the  water-fall.  When  this 
construction  is  ad  >pted,  the  greatest  ef- 
fect will  be  produced  when  the  velocity  of 
the  floatboards  is  not  less  than  ^/  2  a  D  ; 

2.  Sin.  A 

in  which  a  represents  the  accelerating 
force  of  gravity  =  16.087  feet,  B  the 
height  of  the  waterfall,  and  A  the  angle 
which  the  direction  of  the  fall  makes  with 
a  vertical  line.  But  since  this  quantity  in- 
creases as  the  sign  A  decreases,  it  fol- 
lows, that  without  taking  from  the  effect 
of  these  wheels,  we  may  diminish  the  an- 
gle A,  and  thus  augment  considerably  the 
velocity  of  the  floatboards,  according  to 
the  nature  of  the  machinery  employed ; 
whereas  in  vertical  wheels  there  is  only 
one  determinate  velocity,  which  produces 
a  maximum  effect. 

In  the  southern  provinces  of  France, 
where  horizontal  wheels  are  very  gene- 


rally employed,  the  floatboards  are  made 
of  a  curvilineal  form,  so  as  to  be  concave 
towards  the  stream.  The  Chevalier  de 
Borda  observes,  that  in  theory  a  double 
effect  is  produced  when  the  Hoatboards 
are  concave,  but  that  this  effect  is  dimin- 
ished in  practice,  from  the  difficulty  of 
making  the  fluid  enter  and  leave  the  curve 
in  a  p  oper  direction.  Notwithstanding 
this  difficulty,  however,  and  other  detects 
which  might  be  pointed  out,  horizontal 
wheels  with  concave  floatboards  are  al- 
ways superior  to  those  in  which  the  float- 
boards  are  plane,  and  also  to  vertical 
wheels,  when  there  is  a  sufficient  head  of 
water.  If  the  fall  of  water  be  five  or  six 
feet,  a  horizontal  wheel  with  concave 
floatboards  may  be  erected,  whose  maxi- 
mum effect  will  be  to  that  of  ordinary 
vertical  wheels  as  3  to  2. 

On  double  corn-mills — In  order  to  find 
the  weight  of  the  equipage  for  each  mill- 
stone, multiply  the  product  of  the  ex- 
pense of  water  and  the  relative  fall,  by 
481161b.  and  divide  the  product  by  2000, 
if  there  be  two  millstones,  by  3000,  if 
three,  and  so  on  ;  the  quotient  will  be  the 
weight  of  the  equipage  of  each  millstone. 

To  determine  the  radius  of  the  wheel 
that  drives  the  trundles,  find  first  the  ra- 
dius of  the  millstones  by  the  rules  alrea- 
dy given,  and  having  added  it  to  half  the 
distance  between  the  two  neighbouring 
millstones,  [which  quantity  may  be  taken 
at  pleasure,  and  should  be  never  less  than 
2  feet,  however  great  be  the  number  of 
the  millstones]  subtract  from  this  sum 
the  radius  of  the  lantern,  which  may  be 
taken  at  pleasure,  and  the  remainder  will 
be  the  radius  required,  when  there  are 
two  millstones.  But  when  there  are  three 
millstones,  or  four,  or  five,  or  six,  before 
subtracting  the  radius  of  the  lantern,  di- 
vide the  sum  by  0.864,  0.705,  0.587,  or 
0.5,  respectively. 

The  mean  radius  of  the  water-whee! 
may  be  found  by  multiplying  the  square 
root  of  the  relative  fall  by  the  radius  of 
the  millstone,  by  the  radius  of  the  wheel 
that  drives  the  trundles,  and  by  231,  and 
then  dividing  the  product  by  the  radius 
of  the  lantern  multiplied  by  1000,  the 
quotient  will  be  the  wheel's  radius.  It  may 
happen,  however,  that  the  diameter  of  the 
wheel  found  in  this  way  will  be  too  great. 
When  this  is  the  case,  we  may  be  certain 
that  the  radius  of  the  lantern  has  been  ta- 
ken too  small.  In  order  then  to  get  a  less 
value  for  the  wheel's  radius,  increase  a 
little  the  radius  of  the  lantern,  and  find 
new  numbers  both  for  the  water-wheel, 
and  that  which  drives  the  trundles,  by 
the  preceding  rule.  It  may  happen  also 
that  in  giving  an  arbitrary  value  to  the  ra- 


MEC 


MEC 


tlius  of  the  lantern,  the  diameter  of  the 
wheel  found  by  the  rule  may  be  too  small, 
that  is,  less  than  seven  times  the  breadth 
of  the  mill-course  at  the  bottom  of  the 
fall.  When  this  takes  place,  make  the 
diameter  of  tlie  water-wheel  seven  times 
the  width  of  the  mill-course,  and  you  may- 
find  the  radius  of  the  other  wheel  and 
lanterns  by  the  following  rules. 

1.  To  find  the  radius  of  the  wheel  that 
impels  the  trundles ;  add  the  radius  of 
the  millstone  to  half  the  distance  between 
any  two  adjoining  millstones  for  a  first 
quantity.  Multiply  the  square  root  of 
the  relative  fall  by  the  radius  of  the  mill- 
stone and  by  .231,  and  having  divided  the 
product  by  tlie  radius  of  the  water-wheel, 
add  unity  to  the  quotient,  and  multiply 
the  sum  "by  1.  if  there  be  two  millstones, 
by  .864  if  three,  by  .705  if  four,  by  .587  if 
five,  and  by  .5  if  six,  and  the  result  will 
be  a  second  quantity.  Divide  the  first  by 
the  second  quantity,  and  the  quotient  will 
be  the  radius  of  the  wheel  that  drives  the 
trundles. 

2.  To  find  the  radius  of  tlie  lantern, 
multiply  the  radius  of  the  wheel  as  found 
by  the  preceding  rule,  by  the  square  root 
of  the  relative  fall,  and  by  231,  and  di- 
vide the  product  by  the  radius  of  the  wa- 
ter-wheel, the  quotient  will  be  the  lan- 
tern's radius. 

By  the  rules  formerly  given  find  the 
quantity  of  meal  ground  by  one  millstone, 
and  having  multiplied  this  by  the  number 
of  millstones,  the  result  will  be  thequan- 
tkj  ground  by  the  compound  mill. 

If  the  equipage  of  the  millstone  of  a 
vertical  mill  should  be  too  great,  that  is, 
if  it  should  require  too  large  a  millstone, 
then  we  must  employ  a  double  mill,  or 
one  which  has  more  than  two  millstones. 

In  order  to  know  the  equipage  of  each 
millstone,  find  it  by  the  rule  for  a  single 
mill,  and  having  multiplied  the  quantity 
by  .947,  divide  the  product  by  the  num- 
ber of  millstones,  and  the  quotient  will  be 
the  equipage  of  each  millstone- 

On  breast-mills. — A  breast  water-wheel 
partakes  of  the  nat  ure  both  of  an  overshot 
and  of  an  undershot  wheel :  it  is  driven 
partly  by  the  impulse,  but  chiefly  by  the 
weight,  of  tlie  water.  The  effect  of  a 
mill  driven  in  this  manner,  is  equal,  ac- 
cording to  Mr.  Smeaton,  '  to  the  effect  of 
an  undershot  mill,  whose  head  is  equal  to 
the  difference  of  level  between  the  surface 
of  water  in  the  reservoir  and  the  point 
where  it  strikes  the  wheel,  added  to  that 
of  an  overshot,  whose  height  is  equal  to  the 
difference  of  level  between  the  point  where 
It  strikes  the  wheel  and  the  level  of  the 
tail-water.'  M.  Lambert  observes,  that  a 
breast-wheel  should  be  used  when  the  fall 


of  water  is  above  four  feet,  and  below 
ten,  provided  the  discharge  of  water  be 
sufficiently  copious  ;  that  an  undershot 
wheel  should  be  preferred  when  the  fall 
is  below  tour  feet,  and  an  overshot  wheel, 
when  the  fall  exceeds  ten  feet ;  and  that, 
when  the  fall  exceeds  12  feet,  it  should 
be  divided  into  two,  and  two  breast-mills 
erected.  This,  however,  is  only  a  general 
rule,  which  many  circumstances  may  ren- 
der it  necessary  to  overlook.  The  follow- 
ing table,  which  may  be  of  essential  utili- 
ty to  the  practical  mechanic,  is  calculated 
from  the  formulae  of  Lambert  and  exhi- 
bits at  one  view  the  result  of  his  investi- 
gations.— 


TABLE  FOR  BREAST-MILLS. 


Height  of  the 
fall  in  feet.  = 
CD,  Fig.  1. 

to 

n  u  w  to  b  cc      U  U  t- 

Ft.  Dec.  1 

Breadth  of 
the  float 
boards. 

■ 

CO 

t-t  Co  <c 

oo  HHtooDatooicc 
bo  >-»  b.  to  oi  ' 

p 

ETC., 

S°  c  =r 

Ft.  Dec. 

Radius  oft  ic 
water-wheel 
reckoned  fn  m 
the  extremity 
of  the  floats 

Ox 

o>  a>  cn  o»        it*,  cd  go  to 

vo  b*      -sr  CD  00  CD  "o 
OUNNOtCOOiOCOK 

Ft.  Dec. 

Velocity  of 
the  wheel 
per  second. 

o> 

P>  <Jt  Ut  Gt  &       GO  GO  to  M 
O           o  ^l  to  CC  GO  "v| 
^1  CT>CDCC©COi£-ODtOtO 

|Sees.  Dec. 

Tinu-  in 
which  the 

wheel  p'T- 
forms  one 
revolution. 

MHM  MMM 

'.—  ',£>.  u,  '--r  ^  ^  b>  to  6c  be 

OOOCCOOiOOcOOC 

Turns  of 
the  mill 
stone  for 
one  of  the 
wheel. 

00 

oo»-'*^cotocca>coooGo 

C7>  tO  03  ~  CT>  CT>  CO  Ch  if*-  C7> 

lbs.  Avoir. 

[Force  of 
the  water 
upon  the 
float- 
boards. 

popoooopoc 
-^a^a>Crt*'GoGotot-'C 

CT>  CC  O  Go  O  CC  O  00  Ct  CC 

Ft.  Dec. 

The  length 
of  in  n  in 
Fig.  1. 

o 

! 

IOMMMHHOOOC 

to  o  bo  a>  go  h-*  <o  b>  *>-  to 
oo  u  oj  o  n  ^  h  oo  a 

f. 

The  length 
of  ii  o  i» 
Fig.  1. 

J 

1 

HMMMiOOON 

^OC^OjCOrf^CC*'^^ 
"•£>  to  to  Ol  C  o  CO  On  "**>!     '  Go 
GO  O  vc  H-  CC  ON  N  Ot  O 

Cub.  Ft. 

Water  re- 
quired per 
second  to 
turn  the 
wheel. 

MEC 


MEC 


H  is  evident  from  the  preceding  table, 
that,  when  the  height  of  the  fall  is  less 
than  3  feet,  the  depth  of  the  floatboards  is 
so  great,  and  their  breadth  so  small,  that 
the  breast-mill  cannot  well  be  employed ; 
and  on  the  contrary,  when  the  height  of 
the  fall  approaches  "to  ten  feet,  the  depth 
of  the  floatboards  is  too  small  in  proportion 
to  their  breadth.  These  two  extremes, 
therefore,  must  be  avoided  in  practice. 
The  last  column  contains  the  quantity  of 
water  necessary  for  impelling  the  wheel 
but  the  total  expense  of  water  should  al 
ways  exceed  this,  by  the  quantity,  at  least 
which  escapes  between  the  mill-course 
and  the  sides  and  extremities  of  the  float- 
boards. 

Descripiton  of  a  water-wheel.    By  Mr. 
J.  Besant. 


Sir— I  beg  leave  to  lay  before  the  Soci- 
ety for  the  Encouragement  of  Arts,  some 
observations  respecting  the  common  un 
dershot  water-wheel,  and  to  point  out  the 
superiority  of  that  of  my  invention. 

1.  In  common  water-wheels  more  than 
half  the  water  passes  from  the  gate 
through  the  wheel,  without  giving  it  any 
assistance. 

2.  The  floats  coming  out  of  the  tail-wa 
ter  are  resisted  with  almost  the  whole 
weight  of  the  atmosphere,  at  the  instant 
-they  leave  the  surface  of  the  water. 

3.  The  same  quantity  of  water  which 
passed  between  the  floats  at  the  head 
must  of  course  pass  between  them  at  the 
tail,  and  consequently  impede  the  motion 
of  the  wheel. 

In  the  water-wheel  of  my  invention, 

1.  No  water  can  pass  but  what  acts 
with  all  its  force,  on  the  extremity  of  the 
wheel. 

2.  The  floats  coming  out  of  the  water 
in  an  oblique  direction,  prevent  the  weight 
of  the  atmosphere  from  taking  any  eff  ect 

3.  Although  the  new  water-wheel  is 
heavier  than  that  on  the  old  construction 
yet  it  runs  lighter  on  its  axis,  the  water 
having  a  tendency  to  float  it. 

4.  By  experiments  made  with  the  mo 
dels,  proofs  have  been  shown,  that  the 
new  wheel  has  many  advantages  over  the 
common  wheel,  and  that,  when  it  works 
in  deep  tail  water,  it  will  carry  weights 
proportion  of  three  to  one,  so  that  it  will 
be  particularly  serviceable  for  tide-mills 

I  hope  on  trial,  before  the  society,  my 
invention  will  prove  successful. 

Repeated  experiments  of  the  above  in 
vention  were  made  by  the  committee 
from  the  result,  of  which  it  appeared  to 
possess  some  advantages  over  the  com 


mon  wheel,  and  to  have  a  greater  power 
of  action. 

Drescriptlon   of  the  late   Mr.  Besatit\- 
water -wheel.    Plate  X.  Figs.  2  and  3. 

A.  The  body  of  the  water-wheel,  which 
is  hollow  in  the  form  of  a  drum,  and  is  so 
constructed  as  to  be  proof  against  the  ad- 
mission of  water  within  it. 

B.  The  axis  on  which  it  turns. 

C.  The  float  boards  placed  on  the  peri- 
phery of  the  wheel.  Each  board  is  ob- 
liquely fixed  firm  to  the  rim  of  it,  and  to 
the  body  of  the  drum. 

D.  The  reservoir,  containing  the  water. 

E.  The  penstock,  which  regulates  the 
quantity  of  water  running  to  the  wheel. 

F.  The  current  of  water  which  has  pass- 
ed the  wheel. 

Fig.  2.  Is  a  front  view  of  the  water- 
wheel,  showing  the  oblique  direction  in 
which  the  float-boards  C  are  placed  on. 
the  face  of  the  wheel. 


Description  of  a  simple  and  powerful 
capstan. 

This  capstan  is  represented  in  Fig.  4. 
Plate  X.  where  AD  is  a  compound  barrel 
consisting  of  two  cylinders  CD  of  different 
radii.  The  rope  DEC  is  fixed  at  the  ex- 
tremity of  the  cylinder  D,  and  after  pass- 
ing over  the  pulley  E,  which  is  attached 
to  the  load  by  means  of  a  hook  F,  it  is 
coiled  round  the  other  cylinder  C,  and 
fastened  at  its  upper  end.  AB  is  the  bar 
by  which  the  compound  barrel  CD  is  urg- 
ed about  its  axis,  so  that  the  rope  may 
coil  round  the  cylinder  D  while  it  unwinds 
itself  from  the  cylinder  C.  Let  us  now 
suppose  that  the  diameter  of  the  part  D 
of  the  barrel  is  21  inches,  while  the  dia- 
meter of  the  part  C  is  only  20,  and  let  the 
pulley  E  be  20  inches  in  diameter.  It  is 
evident  then  that  when  the  barrel  AD  is 
urged  round  by  a  pressure  exerted  at  the 
point  B,  63  inches  of  rope  will  be  gather- 
ed upon  the  cylinder  D,  and  60  inches  will 
be  unwinded  from  the  cylinder  C  by  one 
revolution  of  the  bar  AB,  these  numbers 
representing  the  circumference  of  each  cy- 
linder. The  quantity  of  wound  rope,  there- 
fore, exceeds  the  quantity  that  is  unwound 
by  63 — 60,  or  3  inches,  the  difference  of 
their  respective  perimeters ;  and  the  half 
of  this  quantity,  or  1^  inch  will  be  the 
space  through  which  the  load  or  the  pul- 
ley E  moves  by  one  turn  of  the  bar.  But 
if  a  simple  capstan  of  the  same  dimensions 
had  been  employed,  the  length  of  rope 
coiled  round  the  barrel  by  one  revolution 
of  the  bar  would  have  been  60  inches,  and 


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MEC 


the  space  described  by  the  pulley  or  load 
to  be  overcome  would  have  been  30  in- 
ches. Now,  it  is  a  maxim  in  mechanics, 
that  the  power  of  any  engine  is  universal- 
ly equal  to  the  velocity  of*  the  impelled 
point  divided  by  the  velocity  of  the  work- 
ing- point,  or  to  the  velocity  of  the  power 
divided  by  the  velocity  of  the  weight ;  that 
is,  to  the  velocity  of  the  point  B  divided 
by  the  velocity  of  the  pulley  E ;  conse- 
quently if  the  lever  in  both  capstans  be 
the  same,  and  the  diameter  of  their  bar- 
rels equal,  the  power  of  the  common  one 
will  be  to  the  power  of  the  improved  one 
as  l\  to  30,  that  is,  inversely  as  the  velo- 
city of  their  weights,  and  the  power  of  the 

latter  will  be  ~=  20,  or  in  other  words, 

1.5 

will  be  equivalent  to  a  20  fold  tackle  of 
pulleys.  If  it  be  wished  to  double  the 
power  of  the  machine,  we  have  only  to 
cover  the  cylinder  C  with  laths  a  quarter 
of  an  inch  thick,  so  that  the  difference  be- 
tween the  radii  of  each  cylinder  may  be 
half  as  little  as  before  ;  for  the  power  of 
the  capstan  increases  as  the  difference  be- 
tween the  radii  of  the  cylinders  is  dimi- 
nished. As  we  increase  the  power,  there- 
fore, we  increase  the  strength  of  our 
machine,  while  all  other  engines  are  pro- 
portionally enfeebled  by  an  augmentation 
of  power.  Were  we,  for  example,  to  in- 
crease the  power  of  the  common  capstan, 
we  must  diminish  the  barrel  in  the  same 
proportion,  supposing  the  bar  or  hand- 
spike not  to  admit  of  being  lengthened, 
and  we  not  only  weaken  its  strength,  but 
destroy  much  of  its  power  by  a  greater 
flexure  or  bending  of  the  ropes. 

The  reader  will  perceive  that  this  cap- 
stan may  be  converted  into  a  crane  or 
windlass  for  raising  weights,  merely  by 
giving  the  compound  barrel  AB  a  hori- 
zontal position,  and  substituting  a  winch 
instead  of  the  bar  AB.  The  superiority 
of  such  a  crane  above  the  common  ones 
is  obvious  from  what  has  been  said;  but 
it  has  this  additional  advantage,  that  it 
allows  the  weight  to  stop  at  any  part  of 
its  progress  without  the  aid  of  a  ratchet 
wheel  and  catch,  from  the  two  parts  of 
the  rope  pulling  on  contrary  sides  of  the 
barrel.  The  rope,  indeed,  which  coils 
round  the  larger  part  of  the  barrel  acts 
with  a  larger  lever,  and  consequently  with 
greater  force  than  the  other;  but  as  this 
excess  of  force  is  not  sufficient  to  over- 
come the  friction  of  the  gudgeons,  the 
weight  remains  stationary  in  any  part  of 
its  path. 

A  crane  of  this  kind  was  erected  in 
1797,  at  Roi  dentown  in  New  Jersey,  by 
Mr   M'Kean  for  the  purpose  of  raising 


logs  of  wood  to  the  frame  of  a  saw  mill, 
which  was  10  feet  distant  from  the  ground. 
The  diameter  of  the  largest  cylinder  was 
2  feet,  and  its  length  3  feet;*  the  other 
cylinder  was  1  foot  in  diameter,  and  of 
the  same  length  with  the  largest.  The 
difference  of  their  circumferences,  there- 
fore, was  3  feet,  and  the  log  would  move 
through  a  space  of  18  inches  with  one 
turn  of  the  handspike ;  and  through  the 
required  height  with  only  8  turns.  The 
length  of  the  bar  or  handspike  was  6  feet, 
which,  at  the  point  where  the  power  was 
applied,  described  a  circle  of  about  30 
feet,  so  that  the  power  of  the  crane  was 
as  1  to  20.  The  length  of  the  rope  was 
only  55  feet,  whereas  if  the  weight  had 
been  raised  through  the  same  height  with 
a  similar  power  by  means  of  a  tackle  of 
pulleys,  £70  feet  of  a  rope  must  have  been 
employed.  In  the  latter  case,  however, 
the  rope  sustains  only  one  twentieth  of 
the  weight,  but  in  the  former  it  supports 
one  half  of  the  load. 

In  describing  a  capstan  of  this  kind,  Dr. 
Robison  asserts,  that  when  the  diameters 
of  the  cylinders  which  compose  the  dou- 
ble barrel  are  as  16  to  17,  and  their  cir- 
cumferences as  48  to  51,  the  pulley  is 
brought  nearer  to  the  capstan  by  about  3 
inches  for  each  revolution  of  the  bar.  This 
however,  is  a  mistake,  as  the  pulley  is 
brought  only  1}2  inch  nearer  the  axis.  This 
will  be  evident,  if  we  conceive  a  quantity 
of  rope  equal  to  the  circumference  of  the 
larger  cylinder  to  be  winded  up  all  at 
once,  and  a  quantity  equal  to  the  cir- 
cumference of  the  lesser  one  to  be  un- 
wihded  all  at  once.  In  the  present  case, 
51  inches  of  rope  will  be  coiled  round  the 
larger  part  of  the  barrel  by  one  revolution 
of  the  capstan  bar,  and  consequently  the 
load  would  be  raised  S\  feet,  the  rope  be- 
ing doubled  Let  48  inches  of  rope  be  now 
un  winded  from  the  lesser  cylinder,  and  the 
load  will  sink  24  feet ;  therefore,  25^—24 
=  1^  foot  is  the  whole  height  or  distance 
through  which  the  weight  has  been  moved. 

Dr.  Robison  affirms  that  the  capstan 
now  described  was  invented  by  an  un- 
taught but  ingenious  country  tradesman. 
It  appears,  however,  to  be  the  invention 
of  the  celebrated  George  Eckhardt,  and 
likewise  that  of  the  late  Mr.  Robert 
M'Kean  of  Philadelphia,  son  of  the  late 
governor  of  Pennsylvania. 

Description  of  Mr.  A.  Andrews's  Crane. 

The  proportion  of  the  beam  in  Fig.  5, 
Plate  X.  is  as  1  to  20,  the  large  weight  be- 
ing five  pounds,  and  the  smaller  one  fourth 
of  a  pound.    The  latter,  when  fixed  on 


MEC 


MEC 


pound.  The  latter,  when  fixed  on  the 
beam-end,  will  equipoise  the  former,  if 
hung  on  the  pulley  at  the  end  of  the  gib- 
beam,  which  should  be  placed  in  a  right 
line  with  the  crane,  at  the  same  time  the 
weight  is  adjusted  ;  otherwise  it  will  oc- 
casion afriction  that  may  prevent  the 
moveable  beam  from  playing  freely. 

The  gib  of  the  crane  stands  on  a  hori- 
zontal beam,  moveable  on  a  centre,  at  A  ; 
(Plate  X.  Fig.  5.)  and  the  distance  of  the 
centre  A,  from  the  bearing  of  the  upright, 
being  to  the  distance  B,  in  the  proportion 
of  1  to  20,  the  weight  placed  at  B,  deter- 
mines that  of  the 'body  suspended  in  the 
same  proportion.  C  is  a  stub,  or  piece  of 
wood,  which  projects  from  the  weight 
hanging  at  the  end  of  the  gib,  and  serves 
to  prevent  the  beam  from  rising  to  too 
great  a  height. 

One  of  the  latest  improvements  in  this 
useful  machine,  is  that  proposed  by  the 
Rev.  E  C.  in  the  2d  vol.  of  the  Repertory 
of  Arts  and  Manufactures. 

Description  of  a  method  of  lifting  forge 
hammers,  or  stampers  for  rice,  piaster 
of  Paris,  &c.  without  noise  or  percus- 
sion. By  Mr.  John  Garnet,  of  New 
Brunswick,  JVeiv  Jersey,  in  a  letter  tp 
Dr.  James  Mease. 

When  heavy  stampers  are  to  be  raised, 
in  order  to  drop  on  the  matters  to  be 
pounded,  a  stroke  or  percussion  is  given, 
that  shakes  the  supporting  frame,  de- 
ranges in  a  little  time  the  machinery,  and 
causes  that  deafhing  noise  from  stamping 
and  fulling-mills  heard  at  a  considerable 
distance. 

To  remedy  tins,  I  have  used  with  suc- 
cess, the  following  method,  which  first 
overcomes  the  vis  inertix  of  the  stampers, 
by  gradual  acceleration,  until  the  requir- 
ed velocity  is  attained,  and  then  conti- 
nues this  velocity  uniformly  to  any  re- 
quired height  of  the  stamper.  Thus, 

Let  HI  (24)  be  a  stamper  in  a  vertical 
position,  on  Which  are  fixed  the  spurs 
C,  D,  and  slider  or  sheeve  N.  GPQ  the 
section  of  a  shaft  or  barrel,  placed  hori- 
zontally to  lift  the  stamper  by  means  of 
a  wiper  MNS  lifting  the  slide's  FN,  and 
teeth  and  tappets  AB,  acting  on  the  spurs 
C,  D ;  for  as  the  barrel  G  revolves,  the 
slider  or  sheeve  N  will  slide  or  roll  along 
the  plane  MN  to  the  point  N,  where  it 
will  have  given  the  stamper  HI  the  pre- 
cise vertical  velocity  of  the  pitch  line  of 
the  teeth  or  tappets  AB  on  the  barrel ; 
these  teeth  will  then  continue  the  velocity 
to  any  required  height,  according  to  their 
number  and  pitch. 
VOL.  II. 


To  construct  the  Wiper,  M  N  S. — From 
the  point  G  the  centre  of  the  shaft,  and  A 
the  pitch  point  of  the  first  tooth  or  tappet 
draw  any  two  parallel  lines  G  M,  A  N, 
but  not  exceeding  30  degrees  from  the 
vertical,  or  making  the  angle  G  A  N  not 
less  than  60  degrees ;  then  any  convenient 
line  M  N  at  right  angles  to,  and  joining 
these  parallel  linesj  will  give  the  length, 
and  position  of  the  wiper. 

Or  a  workman  may  be  directed  to  place 
a  carpenter's  common  iron  square  A  N  M 
on  the  point  A,  the  pitch  of  the  first  tooth, 
at  an  elevation  of  not  more  than  30  de- 
grees from  the  vertical  (G  A  being  hori- 
zontal) then  the  part  N  M  of  the  square 
will  mark  the  required  wiper.  It  is  easy 
to  demonstrate,  (and  may  be  a  neat  pro- 
blem for  some  of  your  mechanical  corres- 
pondents) that  the  point  N  of  the  wiper 
will  give  the  same  vertical  velocity  to  the 
stamper  H I  as  the  pitch  line  of  the  teeth 
or  tappets.  The  wiper  may  be  in  the 
same  or  a  different  plane  from  the  teeth 
A  B,  as  circumstances  may  require. 

To  give  an  example  in  numbers,  the 
following  would  be  found  convenient  for  a 
stamper  to  be  raised  18 or  20  inches:— 

G  A  =  14  inches;  GM  =  10^G  N= 
lG^y  (which  distances  from  the  centre 
G,  can  be  found  by  revolving  the  shaft) 
then  A  N  will  be  17  ^  inches  and  M  N  1 2|- 
\vhich  can  readily  be  marked  by  placing  a 
carpenter's  square  ANMon  the  point  A 
to  N  17  \  inches,  and  drawing  the  line  N 
M  on  the  wiper. 

Description  of  a  Screw  Press,  with  an  ex  - 
panding Power,  by  Mr.  Wm.  Bowler. 

The  screw  and  spring-press  which  1 
have  the  honour  to  present  to  the  inspec- 
ts" 


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tion  and  for  the  approbation  of  the  Society 
for  the  Encouragement  of  Arts,  &.c.  will,  I 
trust,  be  found  in  a  superior  degree  adapt- 
ed to  the  purpose  of  pressing  bodies  in 
general,  but  more  particularly  cheeses, 
appies,  linen,  See.  because  such  things  re- 
quire a  firm  and  unrelaxing  pressure : — 
and  this  is  a  peculiar  advantage  incident 
to  this  machine  ;  formatter  it  is  set,  or  the 
spring  screwed  well  up,  it  will  be  found, 
that  as  the  article  pressed  slninks  from  it, 
so  the  spring,  owing  to  its  peculiar  ex- 
panding power,  gradually  follows  the  ob- 
ject of  its  pressure,  and  hence  continues 
to  maintain  an  uniform  and  equal  action 
on  the  body  on  which  it  is  placed.  This, 
in  cheesC-making,  will  be  found  peculiar- 
ly advantageous ;  for,  it  is  from  this  very 
cause  of  want  of  sufficient  pressing  that 
cheeses  are  frequently  so  very  bad.  Were 
the  curd  entirely  separated  from  the  im- 
pure and  contaminating  mixture  of  the 
whey,  which  must  be  effected  by  the  re- 
gular action  of  this  machine,  we  should 
always  have  the  Cheese  firm  and  whole- 
some ;  and,  I  have  not  a  doubt,  the  press 
will  be  found  equally  useful  in  all  other 
cases,  and  answer  every  purpose,  even 
beyond  expectation,  to  which  it  is  adapted. 

Reference  to  the  Engraving,  Plate  11.  Fig.  1. 

AA,  the  two  upright  sides,  or  frames  of 
the  press. 

B,  the  cross  piece  which  connects  them 
at  the  top,  having  a  hole  in  its  centre,  for 
the  screw. 

C,  a  strong  block  of  wood,  into  which 
the  two  sides  of  the  press  are  firmly  mor- 
tised. 

D,  the  box,  in  which  the  article  to  be 
pressed  is  placed.  This  box  has  a  num- 
ber of  holes  in  its  bottom,  through  which 
the  liquid  matter  when  pressed  out  pass- 
es, and  is  discharged  from  the  mouth  of 
the  spout  K,  a  small  hollow  being  left  un- 
der the  box,  to  allow  its  passage  to  the 
spout.  A  loose  wooden  cover  fits  into  the 
box  D,  and  upon  it  is  fastened  a  stout 
piece  of  timber  F,  and  an  iron  plate  G,  for 
the  point  of  the  screw  of  the  press  to  act 
upon. 

H,  the  male  screw  of  the  press,  working 
in  a  female  screw  in  the  centre  of  the 
strong  cross  piece  I,  which  cross  piece 
slides  up  and  down  in  grooves  within  the 
two  sides  of  the  frame,  one  of  which 
grooves  is  shewn  in  the  plate,  and  about 
half  the  length  of  the  side  piece. 

K,  the  upper  part  of  the  iron  screw,  on 
which  the  handle  L,  which  moves  it,  is 
placed  upon  a  square.  The  iron  of  the 
screw  is  only  wormed  about  half  its 
length. 


M,  a  strong  spiral  spring,  made  of  iron 
wire,  or  iron  rod,  placed  in  the  centre  of 
the  cross  pieces  B  and  I ;  this  spring  press- 
es downwards  against  the  cross  piece  1, 
forcing  it  as  low  down  as  the  side  grooves 
will  permit.  The  male  screw  lilies  within 
the  circle  of  this  spiral ;  and,  when  the 
screw  is  turned,  passes  through  the  fe- 
male screw  below  it,  and  acts  upon  the 
iron  plate  G,  under  which  the  matter  to 
be  pressed  is  placed,  by  continuing  to  turn 
the  screw.  As  it  meets  with  resistance  at 
the  point  G,  it  gradually  forces  back  the 
cross  piece  I,  by  means  of  the  female 
screw  within  it,  and  compresses  the  spiral 
into  a  small  space,  between  the  two  cross 
pieces,  in  which  state  it  remains,  till  the 
article  which  is  pressed  in  the  box  begins 
to  give  out  a  part  of  its  contents.  The 
spiral  spring  M,  compressed  as  above- 
mentioned,  then  begins  to  expand,  and 
exerts  a  continued  re-action  upon  the 
cross  piece  I,  on  the  male  screw  H,  the 
iron  plate  of  which  covers  the  article  un- 
der pressure. 

The  other  figure  is  the  male  screw,  se- 
paratedfrom  the  other  parts,  to  shew  how 
far  the  thread  or  worm  extends  upon  it. 

Machine  for  grinding  Colours,  jrom  the 
Transactions  of  the  Society  for  the  encou- 
ragement of  Jlrts,  itfe. 

Mr.  James  Rawlinson,  of  Derby,  pre- 
sented a  model  of  this  machine  to  the  So- 
ciety of  Arts,  for  which  he  received  the 
silver  medal  and  ten  guineas.  He  used 
the  machine  for  several  years,  and  has 
found  it  much  more  effectual  and  expedi- 
tious in  reducing  the  colours  to  extreme 
fineness,  than  the  usual  method,  and 
much  less  injurious  to  the  health  of  the 
workmen,  who  frequently  have  done  as 
much  with  it  in  three  hours  as  they  could 
in  twelve  with  the  muller  and  slab. 

The  machine  consists  of  a  flat  cylinder 
of  black  marble,  sixteen  inches  and  an  half 
ir.  diameter,  and  four  and  an  half  in  thick- 
ness, with  an  axle  traversing  its  centre 
(thus  somewhat  resembling  a  common 
cutler's  grind-stone.)  fig.  2.  plate  XI.  It 
is  suspended  on  a  similar  frame,  in  a  verti- 
cal position,  and  turned  round  in  the  same 
manner  by  a  winch ;  a  concave  piece  of 
marble  is  provided  of  the  same  breadth  as 
the  circular  stone,  forming  a  segment  of 
the  same  circle  one  third  of  the  circum- 
ference in  extent.  This,  which  may  be 
considered  as  the  muller,  is  fitted  into  a 
piece  of  solid  wood  of  similar  shape,  one 
end  of  which  is  secured  loosely  by  a 
hinge,  or  otherwise  to  the  frame  ;  the  oth- 
er end  rising  over  the  circular  stone  and 
supported  by  it,  is  further  pressed  down 


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on  it  by  a  long1  spring-,  bent  over  from  the 
opposite  extremity  of  the  stand,  and  regu- 
lated, as  to  its  pressure,  by  a  screw,  whose 
end  turns  against  the  concave  muller ;  a 
slight  frame  of  iron  in  front,  moveable  on 
a  hinge,  by  which  it  is  secured  to  the 
frame,  supports  a  scraper  for  taking  off 
the  colour,  formed  of  a  piece  of  watch 
spring,  which  is  turned  back  out  of  the 
way  when  not  in  use. 

Mr.  Rawlinson  thinks  that  the  circular 
grindstones  might  be  made  much  large 
than  that  he  used,  to  advantage,  and  that 
one  of  two  feet  diameter  would  not  occa- 
sion too  much  labour  for  one  man  to  turn 
it.  He  computes,  that  in  his  machine, 
there  are  seventy  sqimre  inches  of  the 
muller  in  constant  work  on  the  paint, 
while  in  the  common  muller,  not  more 
than  sixteen  square  inches  are  usually  in 
contact  with  the  slab.  The  machine  will 
be  found  equally  serviceable  for  the 
colours  ground  in  water,  as  for  those 
prepared  with  oil,  according  to  Mr.  Raw- 
linson, who  highly  recommends  its  use  to 
all  colourmen. 

Mr.  Rawlinson  advises  to  make  up  the 
colours  in  bladders,  and  to  insert  a  bit  of 
quill  or  reed  in  the  neck  of  the  bladder, 
which  will  thus  bind  better  in  tying ;  and 
admitting  of  a  secure  stopper,  will  be 
more  cleanly  and  less  wasteful  than  the 
usual  method  of  stopping  by  a  nail,  and 
keep  the  colour  more  safe  from  the  air. 

Machine  for  grinding  indigo  and  dry  colours. 
Fig.  3,  Plate  XI. 

This  machine  consists  of  a  mortar,  in 
which  it  revolves  by  a  handle,  a  pestle,  or 
muller,  which  is  slit  in  the  middle  in  or- 
der to  faciliate  the  grinding-,  by  changing 
the  position  of  the  indigo,  or  other  colour, 
during  the  operation.  The  figure  repre- 
sents the  different  parts. 

Coats*  Machine  for  paring  Apples. 
The  apple  is  fixed  on  the  three  pronged 
fork  A.,  Fig.  4,  Plate  XI.  and  is  turned  by 
the  handle"  B.  To  the  block  C,  the  knife 
I)  is  fastened  in  the  manner  of  a  spoke 
share.  E  and  F  are  springs  which  fasten 
the  knife  to  the  piece  G,  turning  on  a  pin 
at  II,  while  the  right  hand  turns  the  han- 
dle B,  the  left  presses  against  the  springs 
E  F,  and  turns  the  knife  in  a  semicircle 
over  the  apple.  Dr.  Mease  has  tried  the 
experiment  with  this  machine,  and  found 
it  to  pare  apples  with  great  rapidity. 

Description  of  Mr.  MococPs  Improved  Ma- 
chine for  raising  large  weights. 
A  A,  Fig.  5,  Plate  XI.  arc  the  double 
bandies  of  the  winch. 


R,  represents  the  large  toothed  wheel, 
in  which  the  pinion  on  the  axis  C  works. 

D,  a  ratchet-wheel. 

E,  the  clink,  or  pall,  which  falls  into 
the  teeth  of  the  ratchet,  and  thus  prevents 
the  machine  from  running  back,  in  case 
the  weight  should  at  any  time  overcome 
the  power. 

F,  the  rack,  as  appears  in  jacks  of  the 
common  construction. 

From  a  comparison  of  Mr.  Mocock's 
jack  with  those  in  common  use,  the  for- 
mer  differs  from  the  latter  only  in  one  re- 
spect ;  namely,  that,  in  the  improved  ma- 
chine, a  pall,  or  chick,  and  ratchet,  are 
applied  in  such  a  manner  as  to  stop  the 
machine  in  the  case  abovementioned,  and 
thus  to  prevent  those  melancholy  acci- 
dents which  frequently  occur,  especially 
on  board  of  ships  engaged  in  action ; 
when,  from  inattention,  or  neglect  in  fix- 
ing the  hooks,  or  from  any  other  cause, 
the  common  jacks  fail :  and,  as  the  differ- 
ence in  its  mechanism  is  not  material,  the 
improvement  may  be  easily  applied  to  the 
instruments  already  manufactured. 

Mr.  Terr/ s  Mill,  Fig.  1,  Plate  XII. 

In  the  19th  vol.  of  the  Transactions  of 
the  London  Society  of  Arts,  (1801),  Mr. 
Garnet  Terry,  of  London,  describes  a 
hand-mill  for  grinding  hard  substances, 
which  is  simple  in  its  construction,  and 
may  be  applied  to  a  variety  of  usef  ul  pur- 
poses. The  front  of  the  mill  is  taken  off, 
in  order  to  shew  its  interior  construction. 

DESCRIPTION. 

A,  The  hopper,  the  receptacle  of  the  ar- 
ticles which  are  intended  to  be  ground. 

B,  A  spiral  wire,  in  the  form  of  a  reversed 
cone,  to  regulate  the  delivery  of  them. 

C,  An  inclined  iron  plate,  hung-  upon  a 
pin  on  its  higher  end :  the  lower  end 
rests  on  the  grooved  axis  D,  and  agi- 
tates the  wire  B. 

J  D,  the  grooved  axis,  or  grinding"  cyl  in  - 
j     der,  which  acts  against  the  channeled 
iron-plate  E. 

F,  A  screw  on  the  side  of  the  mill,  by 
means  of  which,  the  iron-plate  E,  is 
brought  nearer  to,  or  removed  further 
from  the  axis  D,  according  as  the  article 
is  wanted  finer  or  coarser. 

G,  the  handle,  by  which  motion  is  given 
to  the  axis. 

H,  The  tube,  whence  the  articles,  when 
ground,  are  received. 
Mr.  Terry  says,  he  has  made  one  on  a 

large  scale,  and  finds  it  answers  the  pur- 
pose of  reducing  to  powder,  coffee,  bones, 
beans,  peas,  malt,  barley,  Sec. 


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Dearborn's  Balance,  of  which  the  follow- 
ing is  a  description. 

Fig.  2,  of  Plate  XII.  is  a  representation 
of  that  part  of  Dearborn's  balance  in 
which  the  pivots  are  placed — a  is  the  cen- 
tre of  motion,  on  which  the  beam  turns  ; 
b  is  the  point  where  the  article  to  be 
weighed  is  suspended ;  and  c  is  the  point 
where  the  poise  is  suspended,  both  being 
on  a  line  with  the  centre  of  motion.  While 
the  beam  remains  level,  the  horizontal 
distances  of  these  points  of  suspension 
are  a  b  and  a  c ;  depress  the  larger  end  of 
the  beam,  until  the  point  b  fails  to  d,  and 
the  point  c  will  rise  to  e ;  it  is  evident, 
that  the  horizontal  distances  are  both  re- 
duced, and  that  this  reduction  of  distan- 
ces on  both  sides  the  centre  of  motion,  is 
always  equal  or  proportional.  Thus,  by- 
placing  the  points  of  suspension  on  a  line 
with  the  centre  of  motion,  by  fixing  the 
centre  of  motion  above  the  centre  of  gra- 
vity, and  by  making  the  arms  of  the  beam 
in  counterpoise,  it  preserves  its  vibrations 
when  light  or  loaded,  and  hence  the  rea- 
sons why  no  art  in  management  can  ren- 
der it  a  fraudulent  instrument. 

Fig.  3,  represents  the  balance  with  its 
apparatus.    ABCD  is  a  wooden  frame, 
with  an  iron  screw  at  E,  on  which  the 
beam  FG  is  suspended.    The  scale  HI  is 
attached  to  the  beam  by  the  clasp  K, 
which  slides  on  the  bar  KI,  to  be  moved 
over  the  centre  of  the  weight  in  the  scale ; 
the  skid  L  is  formed  to  receive  the  scale 
on  one  end,  while  the  other  end  answers 
as  an  inclined  plane,  over  which  the  cask 
M  is  rolled  into  the  scale.  When  the  scale 
is  to  be  charged,  it  is  fixed  at  a  proper 
height,  by  turning  the  screw  E  until  the 
scale  will  rest  fairly  on  the  skid,  when 
the  beam  is  elevated  to  an  angle  of  30  or 
41)  degrees  above  a  horizontal  line.  The 
little  weight  P  (called  the  balance  weight) 
is  a  brass  case,  into  which  a  sufficient 
quantity  of  shot  is  put,  to  produce  an  ex- 
act equipoise  with  the  scale  ;  if  the  weight 
of  the  scale  varies  by  any  cause  the  shot 
is  augmented  or  diminished  accordingly, 
for  which  purpose  the  top  of  the  brass 
case  has  a  small  screw  to  be  taken  out  for 
making  the  change.    The  scale,  when 
charged,  rests  on  the  skid,  by  which  it  is 
kept  out  of  the  mud,  and  at  a  suitable  dis- 
tance from  the  ground  ;  the  small  end  of 
the  beam  is  then  brought  down  by  hand, 
which  raises  the  scale  and  relieves  the 
skid,  if  the  weight  in  the  scale  be  nearly 
under  the  clasp  ;  if  not,  the  beam  is  rais- 
ed un.il  the  scale  rests  again  on  the  skid, 
and  the  clasp  is  loose,  which  is  moved  by 
hand  over  the  weight.    The  beam  being 
again  brought  down,  the  poises  NO  are 


put  on,  and  the  skid  is  drawn  out ;  when 
the  poises  are  so  placed  as  to  produce  a 
level  beam,  the  two  numbers  being  added, 
at  which  the  poises  hang,  will  give  the 
weight  of  the  article.  The  handles  QR 
and  S,  are  for  lifting  the  apparatus  by 
hand,  and  transporting  it  small  distances, 
without  the  trouble  of  taking  it  apart.  T 
is  a  guard,  which  is  useful  when  the  scale 
is  to  be  many  times  charged  with  a  given 
weight  of  sin  all  articles,  in  which  case 
the  beam  may  rest  in  the  guard,  without 
taking  oft' the  poises,  until  all  the  draughts 
are  weighed.  The  principles  on  which  this 
balance  is  predicated,  require  that  the 
larger  poizes  or  weights  attending  it, 
shall  be  multiples  of  the  smaller,  therefore 
the  following  are  the  sizes,  viz.  lib.  21b. 
4lb.  81b.  161b.  and32lb.  and  the  two  sides 
of  a  beam  may  be  graduated  for  any  two 
of  those  weights,  and  may  be  sufficiently 
strong,  for  bearing  any  number  required, 
for  the  largest  draughts.  Under  or  near 
the  beginning  of  the  graduated  edge  of 
every  beam,  on  each  side,  is  stamped  the 
weight  of  the  poise,  for  which  the  respect- 
ive  side  is  marked,  and  in  all  possible  vari- 
ations of  the  weights,  any  article  will  be 
found  to  \\eigh  alike,  when  weighed  with 
the  heavier  weight  alone,  or  the  lighter 
weight  alone,  or  with  both  together,  or 
with  any  greater  number  which  will  pro- 
duce an  equipoise  ;  hence  arises  an  incon- 
trovertible testimony  of  the  accuracy  of 
the  system,  and  of  the  construction  of  the 
balance. 

Balances  of  a  small  size  are  made  for 
domestic  purposes,  and  for  shop-counters, 
which  are  found  exceedingly  convenient, 
when  a  tin  scale  is  attached  to  the  lower 
hook,  and  may  be  rendered  more  pecu- 
liarly so,  by  the  addition  of  another  scale, 
at  sixteen  times  the  distance  from  the  cen- 
tre, for  weighing  ounces. 

Fig.  4,  is  a  representation  of  a  grapnel 
lor  weighing  casks  and  boxes  with  the 
balance,  without  removing  them  from  the 
spot :  a  b  is  a  bar  of  wood  with  holes,  de- 
scribed by  the  black  spots  :  c  is  an  iron  by 
which  the  grapnel  hangs  to  the  balance  ; 
it  is  secured  to  the  bar  by  the  bolts  de  : 
f  g  are  two  irons,  kept  at  proper  distances 
by  the  bolts  h  i :  kkkk  are  tour  points 
about  three  inches  in  length,  which  are 
entered  under  the  ends  of  the  cask  or  box, 
and  lift  it  by  the  draught  of  the  beam, 
The  two  points  of  each*  iron  are  kept  about 
one  fopt  apart,  by  the  little  bolts  1 1  -.mm 
are  two  hooks,  fastened  by  a  few  links  to 
the  irons  ;  these  hooks,  being  thrown  over 
the  bars  QR  and  S,  in  Fig.  3,  keep  the 
two  irons  separate,  a  sufficient  distance 
for  setting  the  apparatus  over  the  next 
cask,  without  interference.   The  height 


MEC 


MEC 


of  the  whole  should  be  nearly  the  height 
of  a  scale  for  weighing  hogsheads,  like 
that  represented  in  Fig.  3,  that  either  the 
grapnel  or  the  scale  may  be  used  with  the 
same  frame.  With  this  apparatus,  but 
two  assistants  are  necessary  lor  weighing 
any  number  of  casks,  as  the  frame,  with 
its  appendages,  is  moved  from  one  to 
another,  and  set  over  them  in  rotation,  by 
two  persons,  with  much  less  labour  than 
would  be  necessary  for  removing  a  heavy 
cask.    See  Balance. 

Of  the  pedometer,  or  odiometer. — The  pe- 
dometer is  a  contrivance  for  measuring  dis- 
tances,  which  is  usually  in  the  form  of  a 
watch  with  wheels,  teeth,  &,c  They  are 
used  by  being  fastened  to  a  string,  chain, 
&c.  to  the  knee  of  a  person,  or  to  a  wheel  of 
a  carriage.  They  advance  one  notch  at  a 
step,  or  each  turn  of  the  wheel.  By  the 
number  being  marked  on  a  dial  plate,  the 
traveller  may  compute  his  progress,  or 
measure  the  distance  from  place  to  place. 
There  are  various  constructions  of  this 
instrument;  some,  therefore,  mark  the 
hour  as  well  as  the  distance-  These  are 
generally  small.  Pedometers,  on  a  larger 
scale,  are  used  also  in  surveying  lands 
Mr.  Edgeworth  has  contrived  one  for  this 
purpose.  The  following  is  a  description 
of  a  pedometer  invented  by  Mr.  Tugwell 
Plate  III.  Fig.  5. 

A,  The  stock  of  the  pedometer. 

B,  B,  B,  &c.  Twelve  spokes  ;  one  end 
of  which  is  fastened  by  means  of  a  screw 
to  the  outward  ring,  or  periphery  of  the 
wheel,  while  the  other  is  inserted  in  the 
stock. 

C,  The  periphery,  which  is  an  iron 
ring  16^  feet,  or  one  pole  in  circumfe 
rence ;  and  which  is  divided  into  25  equal 
parts,  corresponding  to  the  links  of  Gun 
ter's  chain  for  land-measuring,  &c. 

D,  D,  D,  &c.    Are  twelve  small  plates 


ing  towards  its  proper  figure,  denotes  the 
length  of  ground  passed ;  as  it  is  divided 
into  chains  and  poles  on  the  index  of  the 
axis  E,  and  into  links  on  the  periphery  C- 

G,  is  a  small  adjusting  screw  ;  which 
being  turned,  the  style  may  be  removed 
to  the  beginning  of  the  index,  after  the 
given  line,  in  surveying  or  measuring 
land,  has  been  ascertained  in  chains, 
poles,  &c. 

H,  represents  a  cross,  or  square,  with 
sights,  for  determining  perpendiculars  in 
land-measuring.  It  is  suspended  at  its 
ends  on  the  axis,  whence  it  may  be  occa- 
sionally detached  by  a  simple  touch  of  the 
finger  and  thumb,  when  in  use.  Farther, 
this  cross  prevents  the  style  from  being 
revolved  with  the  axis  by  any  accident. 
As  the  320  divisions  marked  on  the  index 
of  the  axis  E,  describe  a  mile,  the  style 
F,  after  having  passed  over  them,  will 
stop  :  and,  as  it  will  now  move  round  with 
the  axis,  it  will  carry  with  it  the  standard  ; 
which  will  strike  on  the  wrist  of  the  ope- 
rator, and  thus  prevent  him  from  proceed- 
ing to  any  farther  distance,  till  he  with* 
draws  his  hand  from  between  such  stand- 
ard and  the  axis.  Having  received  this 
hint,  he  turns  the  screw  G ;  puts  the  style 
F  back  to  the  bottom  of  the  index,  and 
continues  the  revolution  of  the  machine, 
till  he  has  completed  his  course. 

Mr.  Tugwell's  contrivance  is  "^articu^ 
larly  calculated  to  prevent  error  in  mea- 
suring land  ;  as  one  person  may  thus  sur- 
vey with  greater  accuracy  and  expedition, 
than  by  the  use  of  the  chain  alone.  Be- 
sides, no  fraud  can  possibly  be  committed 
by  labourers,  in  measuring  task-work ;  a 
circumstance  of  the  utmost  importance  to 
agriculturists. 

Screw  press  for  packing. — Our  friend 
William  S-  Simmons  Esq.  politely  fur- 
nished us  with  a  draw  ing  of  this  impor- 


representmg  the  separate  spokes,  and  j  taut  invention,  with  the  following  descrip- 
each  of  which  includes  two  links  of  the  tion,  which,  from  its  usefulness,  may  be 
chain  above-mentioned;  the  twelfth  spoke  'considered  a  valuable  application  of  the 
being  divided  at  its  foot,  for  comprehend-  principle  of  the  screw.  It  is  a  patented 
ing  the  25th  link.  invention  [by  one  of  his  family,]  of  which 

E,  An  iron  axis,  being  a  screw  with  320  |  some  notice  was  taken  in  vol.  i.  The  ma- 


circumvolutions,  each  of  which  is  marked 
separately  on  an  engraved  index  on  one 
of  its  sides :  and,  in  order  to  apply  this 
part  of  the  machine,  it  is  screwed  firmly 
into  the  stock  of  the  wheel,  with  which  it 
revolves  when  in  motion. 

F,  A  style,  or  alidade,  being  an  expand 


chine  being  in  operation,  may  be  consi- 
dered as  adequate  to  the  purposes  herein 
after  mentioned. 

"  It  is  used,"  says  Mr.  W  S.  Simmons, 
"  for  the  purpose  of  packing  cotton,  sar- 
saparilla,  tobacco  stems,  flax,  hemp,  pel- 
tries, quercitron  bark,  and  in  fact,  any 


ing  screw-nut,  that  embraces  the  axis, \  articles  that  will  bear  pressure."  He  adds, 
along  which  it  screws,  as  the  latter  re-  j  "  that  this  machine  would  be  very  useful 
volves  with  the  wheel ;  and,  as  each  re-  >  to  the  United  States,  for  packing  clothes, 
volution  describes  an  exact  longitudinal !  blankets,  and  any  articles  that  would  oc- 
pole  (four  of  which  are  computed  to  a  cupy  a  great  bulk."  The  following  is  a 
chain)  the  style  being  pendent,  and  mov-  j  description,  Plate  III.  Fig.  6. 


MEC 

A,  Upright  pieces. 

B,  Packing  beam. 

C,  Top  beam. 

D,  The  follower. 

E,  The  pressing  piece. 

F,  Lever. 

G,  A  windlass  for  drawing  the  hoops 
or  ropes. 

H,  Pedestals  supporting  the  machine. 

I,  Shaft  passing  through  top  beam. 
K,  Screws, 
L,  Wheels. 
M,  The  box. 

N,  The  bale  as  it  appears  when  re- 
lieved from  the  box. 

The  operation  of  packing,  after  the  ar- 
ticle is  prepared,  consists  in  putting  it  into 
three  boxes,  arranged  one  on  the  top  of 
the  other  ;  after  they  are  filled  with  cot- 
ton, they  are  drawn  by  means  of  a  tackle 
under  the  pressing  piece  of  the  machine, 
which  is  then  put  in  operation.  After  the 
pressing  piece  passes  through  box  No.  1, 
and  enters  box  No.  2,  it  is  then  relieved 
from  No.  1.  by  taking  off  its  side;  it  then 
passes  through  box  No.  2  in  the  same 
manner.  The  iron  hoops  are  then  passed 
through  the  holes  on  the  bottom  of  the 
pressing  piece,  and,  by  means  of  the  wind- 
lass, are  drawn  sufficiently  tight,  and  ri- 
vetted.  The  machine  is  then  relieved  from 
the  bale. 


Machine  for  cutting  ivood  screws,  invented 
and  patented  by  R.  Hancock  sen.  and 
Edward  W.  Carr,  of  Philadelphia. 
Plate  XIII. 


Mr.  Carr  favoured  us  with  a  drawing 
of  the  machinery  and  a  specification  of  the 
patent,  of  which  the  following  is  a  de- 
scription. 

The  improved  screw  cutter,  for  cutting 
all  kinds  of  screws  as  far  as  it  can  be  ap- 
plied, is  a  lathe  consisting  of  a  wheel  or 
drum,  pullies  and  spindle,  and  poppets 
that  carry  the  spindle ;  a  bench  of  cast 
iron,  to  which  is  attached  the  poppets  DD, 
also  the  frames  HH  that  support  the  pi- 
vots, which  screws,  regulates,  and  governs 
the  clams  EF.  The  machine  more  parti- 
cularly consists  in  the  construction  of  the 
spindle,  regulating  screws  and  clams  ; 
and  the  cutters  for  forming  the  regulating 
screws  that  are  cut.  The  spindle  AA 
is  formed  with  a  socket  at  each  end ;  on 
the  centre  of  the  spindle  between  the  pop- 
pets is  two  pullies  00,  and  the  band  PP 
is  changed  from  one  to  the  other  by  the 
handle  at  M,  which  stops  or  gives  motion 
to  the  spindle  at  pleasure.   At  one  end  of 


MEC 

the  spindle  is  a  regulating  screw,  which' 
is  changed  as  circumstances  require,  to 
which  is  applied  clams  F,  with  lever  and 
spring  I.  At  the  other  end  is  the  socket 
A,  and  sliding  spring  BB  holding  the  pin 
C  to  be  cut.  When  the  pin  to  be  cut  is 
put  into  the  socket  A,  and  secured  from 
moving  in  the  socket  by  the  end  of  the 
spring  BB  entering  the  slit  in  the  head  of 
the  pin ;  then  the  levers  N  and  K  are  lifted 
up  so  as  to  move  the  joints  JJ,  which 
gently  shut  the  clams  E  and  F  ;  at  the 
same  instant  the  clam  F  takes  hold  of  the 
regulating  screw,  the  clam  E  seizes  the 
pin  to  be  cut  between  two  points  of  the 
cutter,  which  are  fitted  in  four  directions, 
the  single  and  one  double  ;  the  double  is 
notched  in  the  end  so  as  to  form  the  screw 
with  a  true,  smooth,  and  square  thread. 
The  operation  of  cutting  wood  screws  is 
completed  in  about  twice  or  thrice  pass- 
ing back  and  forward  between  the  cutter. 
It  is  contemplated  to  move  the  machine 
by  man,  horse,  water,  or  any  other  power 
most  convenient.  From  10  to  3D  of  these 
machines  may  be  placed  on  one  bench 
and  may  be  moved  with  one  water  wheel 
without  any  interference  with  each 
other. 

A,  Spindle  socket  and  screw. 

B,  Slide  and  spring. 

C,  The  screw  for  cutting.  . 

DD,  The  poppet  that  carries  the  spin- 
dle socket  and  screw. 

EE,  Clams  that  hold  four  cutters. 

FF,  Clams,  the  dyes  for  the  regulating 
the  screws. 

( i,  The  bench. 

1III,  The  frame  that  holds  the  pivots 
for  the  clams. 

I,  The  lever  that  works  by  a  spring  to 
shift  the  spindles. 

3J,  Joints  that  open  and  shut  the  clams. 

K,  The  lever  and  handle  that  works  the 
joints  and  clams. 

L,  The  sliding  plate  under  the  bench, 
that  casts  the  bands  from  one  pulley  to 
the  other. 

M,  Handle  of  sliding  plate. 

N,  Long  lever  that  works  the  front  and 
back  clams. 

00,  Two  pullies  that  carry  the  bands. 
IT,  Band  worked  by  the  drum. 

It,  The  drum. 
S,  The  crank. 
TT,  The  frame. 
U,  The  treddles. 

MECHANICS,  Abstract  of;  or,  a  Re- 
view of  ' the  principal  Definitions  and  Facts 
in  this  science.. 

Of  Matter. 

1.  All  substance,  or  matter,  has  the 


Patent  Machine  tor  Cutting  Wood  Screws. 


MEC 


MEG 


properties  Of  solidity,  or  impenetrability, 
divisibility,  mobility,  and  inertia. 

2.  All  bodies  appear  to  possess  also  at- 
traction and  repulsion. 

3.  Solidity  is  that  property  by  which 
two  bodies  cannot  occupy  the  same  place 
at  the  same  time.  . 

4.  Divisibility  is  that  property  by  which 
bodies  are  capable  of  being'  divided  into 
parts. 

5.  Mobility  is  the  property  of  being-  ca- 
pable of  receiving-  motion  when  imparted 
to  it. 

6.  Inertia  is  the  tendency  which  bodies 
have  to  continue  in  the  state  into  which 
they  are  put,  whether  of  rest  or  motion. 

Space. 

1.  Space  is  either  absolute  or  relative. 

2.  Absolute  space  is  mere  extension  :  it 
has  no  limits  or  bounds,  and  is  itself  im- 
moveable. 

3.  Relative  space  is  that  part  of  abso- 
lute space  which  is  occupied  by  any  body, 
and  is  compared  with  any  part  occupied 
by  another  body. 

Motion. 

1.  Motion  is  also  either  absolute  or  re- 
lative. 

2.  Absolute  motion  is  the  actual  motion 
that  bodies  have,  independent  of  each 
other,  and  only  with  regard  to  the  parts 
of  space. 

3.  Relative  motion  is  the  degree  and 
direction  of  the  motion  of  one  body,  when 
compared  with  that  of  another. 

4.  Accelerated  motion  is  when  the  velo- 
city of  the  motion  continually  increases. 

5.  Retarded  motion  is  when  the  velocity 
continually  decreases. 

6.  The  velocity  of  uniform  motion,  is 
estimated  by  the  time  employed  in  mov- 
ing over  a  certain  space  ;  or  by  the  space 
moved  over  in  a  certain  time. 

7.  To  ascertain  the  velocity,  divide  the 
space  run  over  by  the  time. 

8.  To  know  the  space  run  over,  multi- 
ply the  velocity  by  the  time. 

9.  In  accelerated  motion,  the  space  run 
over  is  as  the  square  of  the  time,  instead 
of  being  directly  as  the  time,  as  in  uni- 
form motion. 

10.  A  body  acted  upon  by  only  one 
force,  must  always  move  in  a  straight 
line. 

11.  Bodies  acted  upon  by  two  single 
impulses,  whether  equal  or  unequal,  must 
also  describe  a  straight  line. 

12.  But  if  a  body  is  acted  upon  by  one 
uniform  force,  or  single  impulse,  and  an- 
other accelerating  force,  these  two  forces 
together  will  cause  it  to  describe  a  curve. 

13.  The  curve  described  by  a  body 


projected  from  the  earth,  and  brought 
down  again  by  the  action  of  gravity,  is 
that  of  a  parabola. 

14.  The  momentum  of  a  body,  is  the 
force  with  which  it  moves,  and  is  in  pro- 
portion to  the  weight,  or  quantity  of  mat- 
ter, multiplied  into  its  velocity. 

Attraction  and  Repulsion. 

1.  The  causes  of  these  powers  are  to- 
tally unknown. 

2.  There  are  various  kinds  of  attrac- 
tion— the  attraction  of  cohesion,  of  gravi- 
tation, of  electricity,  magnetism,  and  che- 
mical attractions. 

3.  The  attraction  of  cohesion  acts  only 
at  very  small  distances. 

4.  The  attraction  of  gravitation,  is  that 
which  masses  of  matter  exert  on  each 
other  at  all  distances. 

5.  Gravitation  decreases  from  the  sur- 
face of  the  earth,  as  the  square  of  the  dis- 
tance.. 

Central  Forces. 

1.  The  central  forces  are  the  centrifugal, 
and  the  centripetal  force. 

2.  The  centrifugal  force  is  the  tenden- 
cy which  bodies  that  revolve  ronnd  a  cen- 
tre have  to  fly  off  from  it  in  a  tangent  to 
the  curve  they  move  in — as  a  stone  from 
a  sling. 

3.  The  centripetal  force,  is  that  which 
prevents  its  flying  off,  by  impelling  it  to- 
wards the  centre— as  the  attraction  of  gra- 
vitation. 

Centre  of  Gravity. 

1.  The  centre  of  gravity,  is  that  point 
in  which  the  weight  of  a  body  may  be 
supposed  to  be  collected. 

2.  A  line  drawn  from  that  point  perpen- 
dicular to  the  horizon,  is  called  the  line  of 
direction. 

3.  When  the  line  of  direction  falls  with- 
in the  base  of  any  body,  that  body  will 
stand ;  but  when  it  falls  without  the  base, 
the  body  will  fall. 

The  Lever. 

1.  There  are  three  kinds  of  levers  :  1. 
When  the  fulcrum,  or  prop,  is  between 
the  power  and  the  weight ;  2.  When  the 
prop  is  at  one  end  of  the  lever,  the  pow- 
er at  the  other,  and  the  weight  between 
them ;  3.  When  the  prop  is  at  one  end, 
the  weight  at  the  other,  and  the  power 
between. 

2.  In  all  kinds  of  levers,  the  power  is  to  . 
the  weight  as  the  distance  of  the  weight 
from  the  fulcrum  is  to  that  of  the  power 
from  the  fulcrum. 

3.  A  bent,  or  hammer  lever,  differs  onty 
in  form,  from  a  lever  of  the  first  kind, 


MEC 


MEC 


4.  A  balance  is  also  a  lever  of  the  first 
kind,  with  equal  arms. 

5.  The  statera,  or  steel-yard,  is  also  the 
first  kind  of  lever,  with  a  moveable  weight. 

Wheel  and  Axle. 

1.  The  power  must  be  to  the  weight, 
in  order  to  have  an  equilibrium,  as  the 
circumference  of  the  wheel  to  the  circum- 
ference of  the  axle. 

2.  As  the  diameters  of  circles  are  in 
proportion  as  their  circumferences,  the 
power  is  to  the  weight  also  as  the  diame- 
ters* 

3.  If  one  wheel  move  another  of  equal 
circumference,  they  will  both  move  equal- 
ly fast. 

4-  But  if  a  wheel  move  another  of  dif- 
ferent diameter,  whether  larger  or  small- 
er, the  velocity  with  which  they  move  will 
be  inversely,  as  their  diameters,  circum- 
ferences, or  number  of  teeth. 

Pulley. 

1.  Pullies  are  of  two  kinds,  fxed,  and 
moveable. 

2.  In  the  fxed  pulley,  when  the  power 
and  weight  are  equal,  they  balance  each 
other,  and  no  mechanical  advantage  is  ob- 
tained 

3.  In  the  moveable  pulley,  the  power 
needs  only  to  be  equal  to  half  the  weight, 
to  balance. 

Inclined  Plane. 
That  the  power  and  weight  may  ba- 
lance each  other,  the  former  must  be  to 
the  latter  as  the  height  of  the  plane  to 
the  length. 

Wedge. 

1.  When  the  resistance  acts  perpendi- 
cularly to  the  sides,  the  power  will  be  to 
the  weight  as  half  the  thickness  of  the 
wedge  on  the  back  is  to  the  length  of  the 
sides. 

2.  When  the  resistance  acts  parallel  to 
the  back,  the  power  is  to  the  resistance 
as  the  whole  length  of  the  back  to  that  of 
the  sides. 

Screw. 

1.  A  screw  may  be  considered  as  an  in- 
clined plane. 

2.  It  is  always  used  with  a  lever  ;  and 
the  power  is  to  the  weight,  as  the  distance 
from  one  thread,  or  spiral,  to  another,  is 
to  the  circumference  of  the  circle  de- 
scribed by  the  power. 

3.  When  a  screw  acts  in  a  wheel,  it  is 
called  an  endless  screw. 

Compound  Machines. 
1.  In  all  machines,  simple  as  well  as 
compound,  what  is  gained  in  power  is 
lost  in  time. 


2.  In  any  machine,  the  power  is  to  the 
weight,  when  in  equilibrio,  in  a  proportion 
formed  by  the  multiplication  of  the  seve- 
ral proportions  which  the  power  bears  to 
the  weight,  in  every  simple  mechanical 
power  used  in  the  machine. 

3.  The  power  of  a  machine  is  not  at 
all  altered  by  varying  the  sizes  of  the 
wheels,  provided  this  proportion  produc- 
ed at  last  by  the  multiplication  of  the  pow- 
er of  each  several  part,  remains  the  same. 

Fly -Wheels. 

1.  Fly-wheels  are  employed  to  equalize 
the  motion  of  a  machine. 

2.  A  fly  cannot  in  any  other  way  add 
power  to  the  machine. 

Friction. 

1.  Friction  depends  upon  the  roughness 
of  bodies. 

2.  It  increases  according  to  the  weight 
and  velocity  of  moving  bodies,  and  also 
according  to  the  surface,  though  in  a  small 
degree. 

Men  and  Horses,  considered  as  first  Movers. 

1.  A  horse  draws  with  the  greatest  ad- 
vantage, when  the  line  of  draught  is  not 
level  with  his  breast,  but  inclines  up- 
wards, making  a  small  angle  with  the  ho- 
rizontal plane. 

2.  When  a  horse  works  in  a  circle,  it 
should  not  be  less  than  40  feet  in  diame- 
ter. 

3-  A  horse  exerts  most  strength,  when 
drawing  horizontally. 

4.  In  turning  a  winch,  a  man  exerts  his 
strength  in  different  proportions  at  differ- 
ent  parts  of  the  circle.  The  greatest  force 
is  when  he  pulls  the  handle  upwards  from 
the  height  of  his  knee;  and  the  least, 
when  he  thrusts  from  him  horizontally. 

5.  The  handles  at  each  end  of  a  winch 
should  be  put  on  at  right  angles  to  each 
other,  and  not  opposite,  as  they  often  are. 

Mills. 

1.  Water-mills  are  of  three  kinds— un- 
dershot-mills, breast-mills,  and  overshot- 
mills.  The  powers  necessary  to  produce 
the  same  effect  on  each  of  these,  must  be 
as  the  numbers,  2.4,  1 75,  and  1. 

2.  But  as  a  fall  of  water  cannot  be  al- 
ways had,  the  under shot-miWs  are  often 
used. 

3.  Bevelled-ivheels  are  much  used  for 
changing  the  direction  of  motion  in  wheel 
work. 

4.  Hook's  universal  joint  is  sometimes 
used  for  the  same  purpose. 

5.  The  ends  of  the  teeth  of  wheels 
ought  never  to  be  circular,  but  formed  of 
parts  of  an  epicycloid. 


MED 


MER 


Pendulums. 

1.  All  the  vibrations  of  the  same  pen- 
dulum, whether  great  or  small,  are  per- 
formed in  equal  times. 

2.  The  longer  a  pendulum,  the  slower 
are  its  vibrations. 

3.  Heat  expands,  and  consequently 
lengthens,  pendulums  ;  and  cold  con- 
tracts, and  shortens  them. 

4.  A  pendulum,  to  vibrate  seconds, 
must  be  shorter  at  the  equator  than  at 
the  poles. 

5.  Methods  have  been  used  for  correct- 
ing- the  irregularity  arising-  from  expan- 
sion and  contraction  :  one  of  these  is  the 
grid iron-pendulum . 

6  Deal  is  the  best  substance  for  pen- 
dulum-rods, as  it  is  very  little  affected  by 
heat  and  cold. 

Wheel-  Carriages.  * 

1.  Wheels  of  carriag-es  turn  round,  on 
account  of  the  friction  they  sustain  in 
contact  with  the  roads. 

2-  Larg-e  wheels,  in  general,  are  more 
advantageous  than  small  ones. 

3.  In  four-wheeled  carriages,  the  fore- 
wheels  are  made  smaller  than  the  hind 
ones,  for  the  conveniency  of  turning-; 
otherwise  they  would  be  better  of  the 
same  size. 

4  Broad  wheels  are  better  for  heavy 
carriag-es — such  as  waggons — because 
they  press  and  harden,  instead  of  cutting 
up  the"  roads,  as  small  wheels  do. 

MEDALS — The  art  of  mating  impres- 
sions, or  copies  of  Medals  and  Coins.  Take 
fish-glue  or  isin-glass  ;  cut  it  in  small 
pieces  ;  immerse  it  in  clear  water,  and  set 
it  on  a  slow  fire;  when  gradually  dissolv- 
ed, let  it  boil  slowly,  stirring  it  with  a  spa- 
tula, and  taking  oft' the  scum.  The  liquor 
being  brought  to  a  sufficient  tenacity, 
take  it  off  the  fire,  let  it  cool  a  little,  and 
then  pour  it  on  the  medal  or  coin  you  in- 
tend to  copy,  so  that  it  may  lay  about  the 
thickness  of  a  crown-piece  upon  the  me- 
dal. This  done,  set  it  in  a  moderate  air, 
neither  too  hot  nor  too  cold,  and  let  it  cool 
and  dry ;  when  dry,  it  will  loosen  itself, 
and  you  will  find  the  impression  exact, 
and  the  finest  strokes  expressed  to  the 
greatest  perfection.  Bui  this  method  is 
surest  on  gold  and  copper  coin,  for  some- 
times it  has  been  found  hurtful  to  those  of 
silver.  You  may  mix  this  liquid  with  va- 
rious colours,  green,  red,  yellow,  blue, 
&c.  If  you  put  a  little  parchment-size  to 
it,  it  will  make  it  harder,  and  answer  your 
purpose  the  better.  In  this  manner  you 
may  make  a  fine  collection,  which  will  an- 
swer your  study  as  well  as  the  real  coins 
or  medals. 

Another,  and  more  substantial  method,— 
VOL.  II. 


Take  a  little  quantity  of  lead,  tin,  and  re- 
gulus  of  antimony ;  and  of  copper,  a  larg- 
er quantity.  Being  melted,  cast  them  in 
a  mould,  prepared  of  burned  clay,  in 
which  clay  you  have  taken  the  impression 
of  both  sides  of  your  medal,  or  coin. — Of 
the  method  of  casting,  see  Moulding 
and  Casting. 

Medals  of  Gum-tragacanth,  to  imprint. 
— Take  six  ounces  of  gum-tragacanth, 
and  steep  it  in  strong  vinegar,  for  the 
space  of  three  days ;  then  beat  and  stir  it 
well  together,  and  add  some  fine  plaster  of 
Paris  to  make  it  of  a  sufficient  substance  : 
if  you  will  have  it  of  a  different  colour, 
you  may  mix  it  with  such  coloured  pow- 
ders as  you  like  best;  if  blue,  with  fine 
smalt ;  if  red,  with  vermilion ;  if  green, 
with  green  verditer,  or  finely  powdered 
verdigrise ;  if  yellow,  with  masticot,  or 
powdered  Dutch  pink ;  if  orange-colour, 
with  orpiment  After  you  have  thus  pre- 
pared your  dough  to  a  proper  consist- 
ence, you  take  your  hollow  forms,  or 
moulds,  and  anoint  them  a  little  with 
sweet-oil,  and  fill  them  with  the  said 
dough,  or  paste,  pressing  it  gently  down 
with  your  fingers  ;  and,  having  trimmed 
it  round  the  rim  with  a  pointed  knife,  set 
it  in  the  sun  to  dry,  and  you  will  have  a 
fair  and  neat  impression  of  your  mould. 
Of  this  paste  you  may  form  and  make  va- 
rious kinds  of  lovs. 

MELTING  FURNACE.  A  number  of 
furnaces  have  been  constructed  for  the 
melting-  of  metal.  For  the  different  modes 
of  melting  metal,  and  of  constructing 
melting  furnaces,  see  Iron,  Copper, 
Zinc,  8cc 

MELASSES,  or  Molasses,  are  that 
gross  fluid  matter  remaining  of  sugar  af- 
ter refining ;  and  which  no  boiling  will 
bring  to  a  consistence  more  solid  than  that 
of  syrup.  Molasses  are  used  with  nitre 
in  the  preservation  of  beef,  in  the  manufac- 
ture of  tobacco,  and,  among  poor  people, 
as  a  substitute  for  sugar.  They  are  also 
distilled  with  water,  after  undergoing  fer- 
mentation, into  a  spirit  somewhat  resem- 
bling that  imported  from  the  West  India 
islands,  though  possessing  a  more  delete- 
rious qua'itv.    See  Sugar. 

MERCURY,  or  Quicksilver— Mer- 
cury is  a  metal  of  a  silvery -white  colour, 
and  fluid  at  the  usual  atmospherical  tem- 
perature. 

Ores  of  Mercury. 
Sp.l.  Native  Mercury. 
Sp.  2.  Native  Amalgam. 
Sp.  3.  Liver-coloured  mercurial  ore. 

1  Var.  Compact. 

2  Var.  Slaty. 

Sp.  4.  Bituminous  mercurial  ore. 
Of  this  are  the  two  following  varieties, 
o 


MER 


MER 


1.  Tar.  Branderz. 

2.  Var.  Corallenerz. 
Sp.  5-  Cinnabar 

Of  this  are  the  three  following'  sub-spe- 
cies. 

1.  Subsp.  Common,  or  dark  red,  C. 

It  occurs  in  mass,  disseminated,  invest- 
ing1, cellular,  der.dritic  or  crystallized. 
The  primitive  form  of  its  crystals  is  the 
regular  hexahedral  prism,  besides  which 
are  other  varieties. 

2.  Subsp.  Fibrous  cinnabar. 

3.  Subsp.  Hepatic  Cinnabar. 
Sp.  6.  Horn  Mercury. 

Reduction  of  Ores. 
The  modes  of  extracting-  the  meal  from 
the  ores  of  mercury  are  very  simple-  The 
first  that  we  shall  mention  is  the  best  and 
most  scientific,  and  practised  at  the  mines 
of  Deux  Ponts,  and  of  Idria.  The  ore  be- 
ing brought  out  Of  the  mine,  is  sorted  by 
hand  with  considerable  accuracy,  reject- 
ing those  parts  that  appear  to  be  destitute 
of  metal.  This  is  an  expensive  and  rather 
tedious  process,  but  has  superseded  the 
ancient  method  of  separating  the  cinnabar 
by  washing,  on  account  of  the  prodigious 
loss  of  metal  in  that  operation.  The  sort- 
ed ere  being  reduced  to  powder  is  care- 
fully mingled  with  one-fifth  more  or  less, 
according  to  the  proportion  of  cinnabar 
contained  in  the  ore,  of  quicklime  which 
has  fallen  to  powder  by  exposure  to  the 
air.  This  mixture  is  then  put  into  iron  re- 
torts, capable  of  holding  about  60  lbs. 
weight,  which,  when  thus  charged,  are 
fixed  in  a  long  furnace,  to  the  number  of 
40  or  50 .  a  glass  receiver  being  then  at- 
tached to  each  retort,  but  not  luted,  a  gen- 
tle lire  is  applied  in  order  to  drive  out  all 
the  moisture  ;  when  this  is  effected,  the 
juncture  of  the  vessels  is  closely  stopped 
with  tempered  clay,  and  a  full  red  heat  is 
applied  for  seven  or  eight  hours ;  at  the 
expiration  of  which  time  all  the  mercury 
will  have  been  volatilized  and  condensed 
in  the  receiver.  The  common  produce 
varies  between  six  and  ten  ounces  of  me- 
tal, from  100  lbs.  of  the  ore. 

The  method  practised  at  Almaden,  in 
Spain,  differs  considerably  from  the  pre- 
ceding, and  is  much  more  rude  and  inarti- 
ficial. The  pieces  of  pure  cinnabar  being 
first  picked  out  from  the  ore,  in  order  to 
be  disposed  of  to  the  painters,  and  manu- 
facturers of  sealing  wax,  the  rest  is  sorted 
into  three  parts :  the  first  is  the  richest, 
and  is  in  pieces  of  a  moderate  size,  the  se- 
cond is  in  smaller  pieces,  and  less  abound- 
ing in  metal,  the  third  is  the  dust  and 
smallest  fragments  of  the  other  two, 
•which  are  kneaded  up  with  clay,  and 
formed  into  bricks,  that  are  dried  care- 
fully in  the  sun.    The  furnace  used  for 


extraction  of  the  mercury  is  an  oblong- 
mass  of  masonry,  divided  horizontally  in- 
to an  upper  and  lower  compartment  by  an 
iron  grate,  and  communicating  near  its 
top  with  a  set  of  aludels.  The  charging 
of  the  furnace  commences  by  laying  on 
the  grate  a  stratum  of  flat  rough  stones, 
leaving  intervals  between  each  for  the  pas- 
sage of  the  fire  :  upon  this  is  laid  a  bed  of 
ore  of  the  s-econd  quality,  then  the  ore  of 
the.  first  quality,  afterwards  another  bed 
of  the  second  kind,  and  at  the  top  of  all  a 
layer  of  the  third  kind  made  up  into 
bricks.  A  tew  faggots  are  now  thrown 
into  the  lower  cavity  of  the  furnace  and 
lighted",  which,  in  proportion  as  they  are 
consumed,  are  succeeded  by  others,  and 
thus  a  gentle  fire  is  kept  up  for  8  or  12 
hours,  according  to  the  previous  dryness 
of  the  ore.  When  the  moisture  is  got  rid 
of,  which  is  known  by  the  cessation  of 
the  vapour,  the  fire-place  is  again  filled 
with  faggots,  and,  before  these  are  con- 
sumed, the  mass  of  ore  will  be  sufficiently 
heated  to  continue  the  combustion  by 
means  of  the  sulphur  that  it  contains  with- 
out any  additional  fuel.  During  the  next 
two  days,  as  the  sulphur  slowly  burns 
away,  the  mercury,  in  the  state  of  vapour, 
passes  into  the  aludels  where  it  is  con- 
densed; and  at  the  end  of  this  period,  all 
the  metal  being  extracted,  the  scorix  are 
taken  out  of  the  furnace,  and  the  aludels 
are  emptied  of  their  contents.  Besides 
the  mercury,  a  considerable  quantity  of  a 
black  matter  like  soot,  is  found  in  the  alu- 
dels, which  is  readily  separated  by  spread- 
ing the  whole  about  on  an  inclined  table  : 
the  mercury  runs  to  the  lower  end,  where 
it  is  collected  in  a  channel,  while  the  im- 
purities remain  behind. 

The  consumption  of  fuel  and  cost  of  ap- 
paratus  is  considerably  less  than  in  the 
German  method,  but  it  is  probable  that  a 
portion  of  mercury  still  remains  in  the  ore. 
A  great  loss  is  also  sustained  by  throwing- 
away  the  soot  after  separating  the  running 
mercury  on  the  tables,  for  not  only  many 
globules  of  the  metal  must  escape  notice, 
but  also  the  calomel,  cinnabar,  Slc*  which 
it  contains,  are  entirely  wasted. 

A  few  of  the  chemical  combinations  of 
mercury,  may  here  be  noticed. 

Mercury  is  a  metal  always  fluid  at  the 
temperature  of  our  climates,  of  a  white 
and  perfectly  resplendent  polished  sur- 
face, so  as  to  reflect  with  extreme  bril- 
liance all  objects,  and  is  without  smell  or 
taste  in  the  metallic  state.  Its  specific 
gravity  is  13.56.  Its  expansion  by  heat  is 
on  the  whole,  very  regular,  till  a  consider- 
able distance  above  the  point  of  boiling' 
water,  and  hence  its  use  in  tbe  construc- 
tion of  thermometers.   When  exposed  to 


MEtt 


MER 


a  cold  of  about— 39  it  solidifies,  and  when 
hard  frozen  it  will  bear  gentle  blows  with 
a  hammer;  sufficient  to  prove  its  mallea- 
bility; though  in  so  doing-,  the  friction  soon 
heats  it  enough  to  make  it  reassnme  the 
liquid  state.  Mercury  boils  at  about  660° 
and,  if  pure,  totally  evaporates  without 
any  residuum  :  but  the  vapour  soon  con- 
denses upon  the  adjacent  bodies,  coating 
them  with  a  white  dew,  which  is  found  by 
the  microscope  to  consist  of  myriads  of 
minute  globules.  When  the  galvanic 
fluid  from  a  powerful  apparatus  is  passed 
into  mercury  by  immersing  the  conduct- 
ing wire  into  this  fluid,  the  mercury  dis- 
perses in  beautiful,  brilliant,  luminous 
stars,  which  seems  to  shew  that  this  is  a 
combustible  metal. 

When  mercury  is  agitated  in  a  dry 
glass  bottle,  the  friction  between  the  me- 
tal and  the  glass  produces  electricity.  If 
the  bottle  be  imperfectly  exhausted",  this 
electricity  passes  into  the  vacuum,  and 
produces  a  light,  which  was  formerly- 
thought  to  be  a  proof  of  the  perfection  of 
the  vacuum  in  the  upper  part  of  barome- 
ter tubes  ;  but  which,  in  fact,  does  not  ap- 
pear in  such  barometers  as  have  been 
cleared  of  air  by  careful  boiling  in  the 
tube. 

The  sulphuric  acid  does  not  acton  this 
metal,  unless  it  be  well  concentrated  and 
boiling.  For  this  purpose  mercury  is 
poured  into  a  glass  retort,  with  near  twice 
its  weight  of  sulphuric  acid.  As  soon  as 
the  mixture  is  heated,  a  strong  efferves- 
cence takes  place,  sulphurous  acid  gas 
escapes,  the  surface  of  the  mercury  be- 
comes white,  and  a  white  powder  is  pro- 
duced :  when  the  gas  ceases  to  come  over, 
the  mercury  is  found  to  be  converted  into 
a  white,  opake,  caustic,  saline  mass,  at 
the  bottom  of  the  retort,  which  weighs 
one  third  more  than  the  mercury,  and  is 
decomposed  by  heat.  Its  fixity  is  consi- 
derably greater  than  that  of  mercury  it- 
self. If  the  heat  be  raised,  it  gives  out  a 
considerable  quantity  of  oxygen,  the  mer- 
cury being  at  the  same  time  revived. 

The  white  mass  produced  by  the  action 
of  sulphuric  acid  upon  mercury,  consists 
partly  of  sulphat  of  mercury,  and  partly 
of  oxide.  Water  separates  the  salt  from 
the  oxide,  which  is  then  of  a  yellow  co- 
lour. Much  washing  is  required  to  pro- 
duce this  colour,  if  cold  water  be  used  ; 
but  if  a  large  quantity  of  hot  water  be 
poured  on,  the  oxyde  immediately  as- 
sumes a  bright  lemon  colour.  In  this 
state  it  is  called  turbith  mineral.  The 
sulphat  affords  by  evaporation  small, 
needly,  deliquescent  crystals.  Sulphat 
of  mercury  may  be  made  likewise  by  add- 


ing soluble  sulphat  to  a  nitric  solution  of 

mercury- 

The  fixed  alkalis,  magnesia,  and  lime, 
precipitate  mercury  from  its  solution; 
these  precipitates  are  reducible  in  closed 
vessels  by  mere  heat  without  addition. 

The  nitric  acid  rapidly  attacks  and  dis- 
solves mercury,  at  the  same  time  that  a 
large  quantity  of  nitrous  gas  is  disengag- 
ed ;  and  the  colour  of  the  acid  becomes 
green  during  its  escape-  Strong  nitric 
acid  takes  up  its  own  weight  of  mercury 
in  the  cold ;  and  this  solution  will  bear  to 
be  diluted  with  water.  But  if  the  solution 
be  made  with  the  assistance  of  heat,  a 
much  larger  quantity  is  dissolved;  and  a 
precipitate  will  be  afforded  by  the  addi- 
tion of  distilled  water,  which  is  of  a  yel- 
low colour  if  the  water  be  hot,  or  white  if 
it  be  cold;  and  greatly  resembles  the  tur- 
bith mineral  produced  with  sulphuric 
acid :  it  has  accordingly  been  called  ni- 
trous turbith.  If  acid  be  added  to  the  so- 
lution made  with  heat,  it  loses  its  proper- 
ty of  being  decomposed  by  water.  This 
decomposition  is  not  complete,  but  only 
deprives  the  acid  of  the  redundant  oxide. 

All  the  combinations  of  mercury  and 
nitric  acid  are  very  caustic,  and  form  a 
deep  purple  or  black  spot  upon  the  skin. 
They  afford  crystals,  which  differ  accord- 
ing to  the  state  of  the  solution.  When 
nitric  acid  has  taken  up  as  much  mercury 
as  it  can  dissolve  by  heat,  it  usually  as- 
sumes the  form  of  a  white  saline  mass. 
When  the  combination  of  nitric  acid  and 
mercury  is  exposed  to  a  gradual  and  long 
continued  low  heat,  it  gives  out  a  portion 
of  nitric  acid,  and  becomes  converted  into 
a  bright  red  oxide,  still  retaining  a  small 
portion  of  acid.  This  is  known  by  the 
name  of  red  precipitate,  and  is  much  used 
as  an  escharotic. 

When  red  precipitate  is  strongly  heat- 
ed, a  large  quantity  of  oxygen  is  disengag- 
ed, together  with  some  nitrogen,  and  the 
mercury  is  sublimed  in  the  metallic  form. 

Nitrat  of  mercury  is  more  soluble  in  hot 
than  cold  water,  and  affords  crystals  by 
cooling.  It  is  decomposed  by  the  affusion 
of  a  large  quantity  of  water,  unless  the 
acid  be  in  excess. 

When  mercury  is  dissolved  in  nitric 
acid  by  means  of  heat,  nitrous  gas  is  emitt- 
ed at  first;  and  afterward  it  ceases, 
though  the  solution  still  proceeds.  If  the 
solution  be  stopped  in  the  first  part  of  the 
process,  pure  alkalies  precipitate  the  yel- 
low oxyd ;  but  if  the  solution  be  continued 
after  the  escape  of  the  elastic  fluid  has 
ceased,  the  precipitate  obtained  by  the 
same  means  is  black. 

Barytes,  magnesia,  and  lime,  precipi- 


MER 


MER 


tate  the  nitric  solutions  of  mercury  ;  and 
these  precipitates,  as  well  as  all  the  other 
oxides  of  this  metal,  are  reducible  by  heat 
alone  without  addition. 

The  precipitates  of  mercury  from  acids, 
by  means  of  alkalies,  possess"  the  proper- 
ty of  exploding  when  exposed  to  a  gra- 
dual heat  in  an  iron  spoon,  after  having 
been  previously  triturated  with  one-sixth 
of  their  weight  of  flowers  of  sulphur 
The  residue  consists  of  a  violet-coloured 
powder,  which  is  converted  by  sublima- 
tion into  cinnabar.  It  seems  therefore,  as 
if  the  sulphur  combined  suddenly  with 
the  mercury,  and  expelled  oxygen  in  the 
elastic  state. 

Another  fulminating  preparation  of 
mercury  was  discovered  by  Mr.  Howard. 
An  hundred  grains  of  mercury  are  to  be 
dissolved  by  heat  in  an  ounce  and  half,  by 
•  measure,  of  nitric  acid.  This  solution  be- 
ing poured  cold  into  two  ounces  by  mea- 
sure of  alcohol  in  a  glass  vessel,  heat  is  to 
be  applied,  till  effervescence  is  excited.  A 
white  vapour  undulates  on  the  surface, 
and  a  powder  is  gradually  precipitated, 
which  is  immediately  to  be  collected  on  a 
filtre,  well  washed,  and  cautiously  dried 
with  a  very  moderate  heat.  This  powder 
detonates  loudly  by  gentle  heat,  or  slight 
friction.  Mr.  Accum  having  made  four 
ounces  of  this  powder,  and  left  it  to  dry 
on  a  chalk  stone,  where  it  was  forgotten 
for  three  months,  found  it  converted  into 
a  brilliant  black  powder ;  and  on  collect- 
ing it  into  a  heap,  observed  a  globule  of 
running  mercury.  On  putting  it  into  a 
bottle,  and  shaking  it,  heat  was  evolved, 
and  the  whole  of  the  metal  recfuced. 
Bmgnatelli  has  made  this  preparation 
without  heat,  by  pouring  an  ounce  of  al- 
cohol on  two  drachms  of  yellow  oxyde  of 
mercury,  and  adding  at  twice,  ten  drachms 
of  strong  fuming  nitrous  acid.  The  alco- 
hol is  converted  into  ether,  which  escapes 
in  very  copious  vapours.  All  the  other 
oxides  of  mercury  were  equally  converti- 
ble into  fulminating  mercury  by  the  same 
means.  In  either  way  the  ether  might  be 
saved  by  a  proper  apparatus. 

The  acetous  and  most  other  acids  com- 
bine with  the  oxyde  of  mercury,  and  pre- 
cipitate it  from  its  solution  in  the  nitric 
acid. 

The  muriatic  acid  seizes  the  mercury 
dissolved  in  the  nitric  acid,  and  forms  a 
compound  which  falls  to  the  bottom.  This 
consists  of  a  very  caustic  salt,  which  is 
called  corrosive  sublimate,  and  is  produc- 
ed when  the  nitric  solution  contains  high- 
ly oxided  mercury  ;  but  when  that  solu- 
tion is  saturated  with  mercury  in  a  less 
oxided  state,  the  compound  which  falls 
down  by  the  addition  of  muriatic  acid  is 


called  white  precipitate,  and  differs  little 
from  the  preparation  which,  when  made 
in  the  dry  way,  is  called  calomel,  or  mer- 
curius  dulcis. 

The  muriatic  acid  docs  not  act  percep- 
tibly upon  mercury  in  the  metallic  state  ; 
but  the  oxigenized  muriatic  acid  readily 
dissolves  it,  and  forms  the  same  combina- 
tion as  arises  from  the  direct  union  of  mu- 
riatic acid  with  oxyde  of  mercury  ;  that  is 
to  say,  corrosive  sublimate.  This  is  gene- 
rally  made  by  mixing  sulphat  of  mercury 
with  muriat  of  soda,  and  exposing  them 
to  heat  gradually  raised ;  when  the  muriat 
of  mercury  sublimes.  This  muriat  being 
mixed  by  trituration  with  three-fourths  its 
weight  of  mercury,  and  sublimed  again  ; 
the  sublimate  powdered,  and  re-sublimed 
three  or  four  times ;  and  the  product  well 
washed ;  we  have  the  mild  muriat,  or  ca- 
lomel. The  corrosive  muriat  contains, 
according  to  Mr.  Chenevix,  697  mercury, 
12  3  oxygen,  and  18  muriatic  acid  :  the 
mild,  7*9  mercury,  9  5  oxygen,  and  115 
acid. 

The  causticity  of  metallic  salts  depends 
chiefly  on  the  disposition  of  the  oxide  to 
resume  the  metallic  state,  in  doing  which 
it  burns  the  substance  to  which  it  may  be 
applied  by  the  oxigen  it  evolves.  It  is  ac- 
cordingly found,  that  corrosive  sublimate 
possesses  this  property  in  a  very  eminent 
degree  ;  it  is  therefore  one  of  the  most  ac- 
tive mineral  poisons.  This  salt  is  soluble 
in  water,  though  sparingly,  and  also  in  al- 
cohol. It  is  precipitated  of  an  orange  co- 
lour by  fixed  alkalis.  The  absorbent  earths 
likewise  throw  down  its  oxide.  Volatile 
alkaii  affords  a  white  precipitate,  which 
soon  afterward  assumes  a  slate  colour. 

Corrosive  sublimate  becomes  much  more 
soluble  in  Mater  by  the  addition  of  sal  am- 
moniac, with  which  it  forms  a  triple  com- 
pound, called  sal  alembroth  by  the  alche- 
mists, which  crystallizes  by  cooling.  The 
addition  of  a  fixed  alkali  throws  down  a 
white  oxide  of  mercury,  called  white  calx 
of  quicksilver  in  the  London  Dispensa- 
tory. 

When  one  part  of  native  sulphuret  of 
antimony  is  triturated  or  accurately  mixed 
with  two  parts  of  corrosive  sublimate,  and 
exposed  to  distillation,  the  oxigenized  mu- 
riatic acid  combines  with  the  antimony, 
and  rises  in  the  form  of  the  compound 
called  butter  of  antimony;  while  the  sul- 
phur combines  with  the  mercury,  and 
forms  cinnabar.  If  antimony  be  used  in- 
stead of  the  sulphuret,  the  residue  which 
rises  last  consists  of  running  mercury,  in- 
stead of  cinnabar. 

Mercury  combines  very  readily  with 
sulphur.  By  trituration  in  a  mortar  the 
mercury  disappears,  and  forms  a  black 


MER 


MER 


sulphuret,  which  was  formerly  called 
ethiops  mineral,  or  mercurial  ethiops. 
The  combination  is  more  speedily  made 
by  mixing  fluid  mercury  with  melted  sul- 
phur. In  this  way  three  parts  of  flowers 
of  sulphur  unite  with  one  of  mercury.  If 
the  sulphur  be  set  on  fire,  the  greater 
part  burns,  and  the  remainder  is  of  a  vio- 
let colour  when  pulverized.  This  consists 
of  a  more  intimate  combination  of  mer- 
cury and  sulphur.  It  rises  in  a  heat  nearly 
approaching"  to  redness  ;  and  the  subli- 
mate, which  is  called  cinnabar,  contains 
abont  one  fifth  part  sulphur,  and  the  rest 
mercury.  Mr.  Accum  lias  made  cinnabar 
in  the  humid  way,  by  mixing  equal  parts 
of  concentrated  solutions  of  oxigenized 
muriat  of  mercury  and  fresh  prepared 
fuming  hydrosulphuret  of  ammonia.  A 
brownish  muddy  precipitate  is  produced, 
which,  being  left  undisturbed,  turns  yel- 
low in  three  or  four  days,  then  orange,  and 
at  last  the  beautiful  red  of  the  best  ver- 
milion. Proust  says,  that  mercury,  pour- 
ed into  flasks  containing  sulphuret  of  pot- 
ash or  of  ammonia,  unites  with  the  sul- 
phur, and  falft  down  in  a  black  powder, 
which  in  the  space  of  a  few  days  becomes 
red.  According  to  Seguin,  cinnabar  is  com- 
posed uniformly  of  86|  mercury,  and  13|f 
sulphur  ;  while  in  the  black  sulphuret  the 
proportions  are  very  variable.  In  the  na- 
tive cinnabar  of  Japan,  however,  Klaproth 
found  14.75  per  cent  of  sulphur,  and  in 
that  of  Carniola  14.25.  The  pigment  call- 
ed vermilion  consists  of  artificial  cinnabar 
reduced  to  a  powder. 

If  phosphorus  be  added  to  a  nitric  so- 
lution of  mercury,  the  metal  will  be  pre- 
cipitated on  it  in  globules,  which  will  be 
converted  into  a  black  phosphuret  by 
heating  to  ebullition. 

Mercury  unites  by  trituration  with  dense 
oils  and  mucilages,  with  which  it  forms 
black  or  deep  blue  compounds.  A  small 
part  of  the  mercury  in  these  seems  to  be 
in  combination,  and  the  rest  in  a  state  of 
extreme  division.  Rancid  oils  combine 
with  mercury  better  than  such  as  are 
fresh. 

Mercury,  being  habitually  fluid,  very 
readily  combines  with  most  of  the  metals, 
to  which  it  communicates  more  or  less  of 
its  fusibility.  When  these  metallic  mix-  j 
tures  contain  a  sufficient  quantity  of  mer- 
cury to  render  them  soft  at  a  mean  tem- 
perature, they  are  called  amalgams. 

It  very  readily  combines  with  gold,  sil- 
ver, lead,  tin,  bismuth,  and  zinc  ;  more 
difficultly  with  copper,  arsenic  and  anti- 
mony ;  and  scarcely  at  all  with  plating  or 
iron :  it  does  not  unite  with  nickel,  man- 
ganese, or  cobalt :  and  its  action  on 
tungsten  and  molybdena  is  not  known. 


Looking-glasses  are  covered  on  the  back 
surface  with  an  amalgam  of  tin-  Sec 
Silvering. 

The  uses  of  mercury  have  already  been 
mentioned  in  the  present  article,  and  else- 
where.  The  amalgamation  of*  the  noble 
metals,  water-gilding,  the  making  of  ver- 
milion, the  silvering  of  looking-glasses, 
the  making  of  barometers  and  thermome- 
ters, and  the  preparation  of  several  pow- 
erful medicines,  are  the  principal  uses  to 
which  this  metal  is  applied. 

From  the  importance  of  the  medicinal 
uses  of  this  metal,  and  of  having-  it  per- 
fectly pure  for  many  other  purposes,  we 
shall  subjoin  the  following  methods  of  de- 
tecting adulterations,  either  of  the  metal 
itself,  or  its  principal  preparations,  from 
Mr.  Henry. 

Scarcely  any  substance  is  so  liable  to 
adulteration  as  mercury,  owing  to  the  pro- 
perty which  it  possesses  of  dissolving  com- 
pletely some  of  the  baser  metals.  This 
union  is  so  strong,  that  they  even  rise 
along-  with  the  quicksilver  when  distilled. 
The  impurity  of*  mercury  is  generally  in- 
dicated by  its  dull  aspect ;  by  its  tarnish- 
ing, and  becoming  covered  with  a  coat  of 
oxide,  on  long  exposure  to  the  air ;  by 
its  adhesion  to  the  surface  of  glass  ;  and, 
when  shaken  with  water  in  a  bottle,  by 
the  speedy  formation  of  a  black  powder. 
Lead  and  tin  are  frequent  impurities,  and 
the  mercury  becomes  capable  of  taking-  up 
more  of  these,  if  zinc  or  bismuth  be  pre- 
viously added.  In  order  to  discover  lead, 
the  mercury  may  be  agitated  with  a  little 
water,  in  order  to  oxidize  that  metal.  Pour 
off  the  water,  and  digest  the  mercury  with 
a  little  acetous  acid.  This  will  dissolve 
the  oxide  of  lead,  which  will  be  indicated 
by  a  blackish  precipitate  with  sulphuretted 
water.  Or  to  this  acetous  solution  add  a 
little  sulphat  of  soda,  which  will  precipi- 
tate a  sulphat  of  lead,  containing-,  when 
dry,  72  per  cent,  of  metal.  If  only  a  very 
minute  quantity  of  lead  be  present  in  a. 
large  quantity  of  mercury,  it  may  be  de- 
tected by  solution  in  nitric  acid,  and  the 
addition  of  sulphuretted  water.  A  dark 
brown  precipitate  will  ensue,  and  will 
subside  if  allowed  to  stand  a  few  days. 
One  part  of  lead  may  thus  be  separated 
from  15263  parts  of  mercury.  Bismuth 
is  detected  by  pouring  a  nitric  solution, 
prepared  without  heat,  into  distilled  wa- 
ter ;  a  white  precipitate  will  appear  if  this 
metal  be  present.  Tin  is  manifested,  in 
like  manner,  by  a  weak  solution  of  nitro- 
muriat  of  gold,  which  throws  doing  a 
purple  sediment ;  and  zinc  by  exposing* 
the  metal  to  heat. 

The  red  oxide  is  rarely  found  adulterat- 
ed, as  it  would  be  difficult  to  find  a  sub- 


MER 


MET 


stance  well  suited  to  this  purpose.  If  well 
prepared,  it  may  be  totally  volatilized  by 
heat. 

The  red  oxide  of  mercury  by  nitric  acid 
is  very  liable  to  adulteration  with  red 
lead.  This  fraud  may  be  discovered  by 
digesting  it  in  acetic  acid,  and  adding  to 
the  solution  sulphuretted  water,  or  sul- 
phuret  of  ammonia,  which  produces,  with 
the  compounds  of  lead,  a  duty  dark -co- 
loured precipitate.  It  should  also  be  to- 
tally volatilized  by  heat. 

White  oxide  of  mercury.  White  lead 
is  the  most  probable  adulteration  of  this 
substance,  and  chalk  may  also  be  occa- 
sionally mixed  with  it.  The  oxide  of  lead 
may  be  discovered  as  in  the  last  article ; 
and  chalk,  by  adding  to  the  dilute  solution 
a  little  oxalic  acid. 

Red  sulphuret  of  mercury  is  frequently 
adulterated  with  red  lead ;  which  may  be 
detected  by  the  foregoing  rules.  Chalk 
and  dragon's  blood  are  also  sometimes 
mixed  with  it.  The  chalk  is  discovered 
by  an  effervescence  on  adding  acetic  acid, 
and  by  pouring  oxalic  acid  into  the  ace- 
tous solution.  Dragon's  blood  will  be 
left  unvolatiiized  when  the  sulphuret  is 
exposed  to  heat,  and  may  be  detected  by 
its  giving  a  colour  to  alcohol,  when  the 
cinnabar  is  digested  with  it. 

Black  sulphuret  of  mercury.  The  mer- 
cury and  sulphur,  in  this  preparation, 
should  be  so  intimately  combined,  that  no 
globules  of  the  metal  can  be  discovered 
by  a  magnifier;  and  that,  when  rubbed 
on  gold,  no  white  stain  may  be  communi- 
cated. The  admixture  of  ivory  black  may 
be  detected  by  its  not  being  wholly  vola- 
tilized by  heat. 

Yellow  oxide,  or  sub-sulphat  of  mercu- 
ry, should  be  wholly  evaporabie,  and, 
when  digested  with  distilled  Water,  the 
water  ought  not  to  take  up  any  sulphuric 
acid,  which  will  be  discovered  by  muriat 
of  barytes. 

Corrosive  muriat  of  mercury.  If  there 
be  any  reason  to  suspect  arsenic  in  this 
salt,  the  fraud  may  be  discovered  as  fol- 
lows :  Dissolve  a  small  quantity  of  the 
sublimate  in  distilled  water ;  add  a  solu- 
tion of  caibonat  of  ammonia  till  the  pre- 
cipitation ceases,  and  filter  the  solution. 
If,  on  the  addition  of  a  few  drops  of  am- 
moniated  copper  to  this  solution,  a  preci- 
pitate of  a  yellowish  green  colour  be  pro- 
duced, the  sublimate  contains  arsenic. 

Sub-muriat  of  mercury,  or  calomel, 
should  be  completely  saturated  with  mer- 
cury. This  may  be  ascertained  by  boil- 
ing, for  a  few  minutes,  one  part  of  calo- 
mel with  a  thirty-second  part  of  muriat  of 
ammonia  in  ten  parts  of  distilled  water. 
When  carbon  at  of  potash  is  added  to  the 


filtered  solution,  no  precipitation  will  en  • 
sue,  if  the  calomel  be  pure.  This  prepa- 
ration, when  rubbed  in  an  earthen  mortar 
with  pure  ammonia,  should  become  in- 
tensely black,  and  should  exhibit  nothing 
of  an  orange  hue. 

METALS. — Metallic  substances  are  ve- 
ry easily  distinguishable  from  all  other 
bodies  in  nature,  by  their  very  great 
weight,  and  that  opake  shining  appear- 
ance, which  is  called  the  metallic  splen- 
dour or  brilliancy.  Very  few  substances 
have  half  the  specific  gravity  of  the  light- 
est among  the  metals.  They  are  all  fusi- 
ble, though  at  very  different  tempera- 
tures ;  and  if  the  fusion  be  made  in  close 
vessels,  they  fix  again  by  cold,  without 
having  suffered  any  change  but  that  of  ex- 
ternal figure,  which  must  be  produced  in 
all  bodies  which  have  been  either  lique- 
fied or  volatilized ;  namely,  they  assume 
the  form  of  the  vessel  which  contains 
them.  Some  of  them  may  be  extended 
considerably  by  the  hammer,  without 
breaking  them.  This  property  is  called 
malleability  ;  and  the  metallic  bodies 
which  possess  it  are  callea  entire  metals, 
or  metals,  in  contradistinction  to  such  as 
are  more  brittle,  and  are  called  semime- 
tals.  Metallic  substances  are  also  called 
perfect  and  imperfect.  The  perfect  are 
such  as  undrego  no  lasting  change  of  their 
properties  by  any  heat  we  can  apply  to 
them,  at  least  in  common  furnaces.  The 
imperfect  metals,  when  exposed  to  a 
strong  heat,  with  access  of  oxigen,  are 
changed,  by  a  process  similar  to  burning, 
and  in  some  of  them  with  an  actual  flame, 
into  a  brittle  dull  substance,  called  an  ox- 
ide, which  is  heavier  than  the  metal  it 
came  from,  though  its  specific  gravity  is 
not  so  great.  Some  are  even  converted 
into  acids.  If  the  oxide  of  a  metal  be  ex- 
posed to  strong  heat  in  a  closed  vessel, 
with  some  inflammable  matter,  it  recovers 
its  metallic  state.  This  is  called  reduc- 
tion, or  reviving  of  the  metal. 

A  more  recent  arrangement  of  metals, 
and  perhaps  the  best,  is  that  of  Dr.  Thom- 
son, who  divides  them  into  4  classes.  1. 
Malleable  metals.  Platina,  gold,  silver, 
nickel,  mercury,  palladium,  rhodium,  iri- 
dium, osmium,  copper,  iron,  tin,  lead,  and 
zinc.  2.  Brittle  and  easily  fined.  Bismuth, 
antimony,  tellurium,  and  arsenic.  3. 
Brittle  and  difficult  of  fusion.  Cobalt, 
manganese,  chrome,  molybdena,  uranium, 
tungsten,  and  titanium.  4.  liefractory, 
or  such  as  have  never  yet  been  reduced. 
Columbium,  tantalium,  and  cerium. 

Metals,  like  other  fusible  bodies,  have 
each  a  fixed  temperature,  or  freezing 
point,  at  which  they  become  solid.  They 
assume  a  crystallized  figure  in  cooling, 


MET 


MET 


which  is  different  in  each,  and  may  be 
seen  by  fusing-  them  in  melting- -pots  with 
a  hole  in  the  bottom  stopped  with  a  stop- 
per ;  or  better,  in  many  cases,  by  a  dish 
or  flat  mould,  and  tilting  it ;  for,  in  this 
case,  if  the  surface  be  suffered  to  con- 
geal, and  the  fluid  metal  beneath  be  suf- 
fered to  run  out  through  the  hole,  the  un- 
der surface  of  the  remaining  metal  will  be 
curiously  crystallized.  The  Specific  gra- 
vity of  metallic  substances  is  very  consi 
derably  affected  by  the  gradual  or  hasty 
cooling,  or  transition  from  the  fluid  to  the 
s.olid  state.  Hammering  renders  them 
harder  and  more  elastic ;  but  this  effect  is 
destroyed  by  ignition. 

The  affinities  of  metals  to  each  other 
are  various.  Some  will  not  unite  at  all ; 
others  mix  very  readily,  and  even  com- 
bine together.  On  this  property  is  found- 
ed the  art  of  soldering  ;  which  consists  in 
joining  two  pieces  of  metal  together  by 
heating  them,  with  a  thin  piece  or  plate  of 
a  more  fusible  metal  interposed  between 
them.  Thus  tin  is  a  solder  for  lead ; 
brass,  gold,  or  silver,  are  solders,  for  iron, 
&c> 

Mountainous  districts,  where  the  sur- 
face of  the  globe  has  been  thrown  up  or 
disturbed,  in  remote  ages,  by  earthquakes, 
volcanoes,  or  other  great  convulsions  of 
nature,  are  the  most  abundant  in  metal- 
lic bodies.  In  digging  into  the  bowels  of 
the  earth,  the  various  metals  are  mostly 
found  disposed  in  strata  or  beds,  which 
in  plains  lie  level,  but  in  mountains  are  in- 
clined ;  whence  it  happens,  that  in  moun- 
tainous countries  some  strata  are  often 
exposed  to  the  day,  which  would  else 
have  been  too  deeply  lodged  to  be  come 
at  by  human  art.  It  is  in  the  stratified 
mountains  that  metals  are  usually  found, 
mostly  in  a  state  of  combination  either 
with  sulphur  or  arsenic,  or  in  the  state  of 
an  oxide.  They  are  also  found,  though 
less  frequently,  in  the  metallic  or  native 
state. 

The  combinations,  or  earthy  bodies 
which  contain  metals  in  sufficient  quan- 
tity to  be  worth  extracting,  are  called 
ores.  Iron  ore  sometimes  forms  entire 
mountains ;  but  in  general  the  metallic 
part  of  a  mountain  is  very  inconsiderable 
in  proportion  to  the  whole.  The  ores  run 
either  parallel  to  the  stony  strata,  though 
far  from  having  the  same  regularity  of 
thickness,  or  they  cross  the  strata  in  all 
directions.  These  metallic  strata  are 
called  veins.  The  cavity  formed  by  art 
in  the  earth,  for  the  extraction  of  metals 
or  any  other  mineral  bodies,  is  called  a 
mine.  The  stone,  wherein  a  metallic  ore 
is  usually  bedded,  is  called  its  matrix. 
These  are  not  peculiarly  appropriated  to 


any  metal,  though  some  stones  more  fre- 
quently accompany  metals  than  others. 

The  general  operations  by  which  me- 
tals are  obtained  f  rom  ores,  are — 1.  The 
minerals  are  selected  ;  and  such  only  are 
taken  as  from  experience  are  known,  by 
the  external  figure  or  appearnce,  to  cou- 
tain  metal.  2.  They  are  reduced  to  pow- 
der ;  and  the  lighter  parts  washed  away, 
by  means  of  water,  in  a  shallow  trough. 
3.  The  volatile  parts  are  dissipated  by 
the  operation  called  roasting.  4.  The 
ores  are  smelted  by  throwing  them  into 
the  midst  of  the  fuel  of  a  furnace,  with 
earthy  substances,  which  are  disposed  to 
run  into  glass.  In  this  operation,  the 
glassy  matter,  called  scoria,  in  some  mea- 
sure produces  the  effect  of  rendering  the 
lower  part  of  the  furnace  a  closed  vessel ; 
and  the  fuel  revives  the  metal,  which  in 
the  ore  is  usually  of  the  nature  of  oxide. 
The  revived  metal  being  much  denser 
than  the  scoria,  falls  to  the  botLom,  and  is 
suffered  to  run  out  by  proper  openings. 
These  are  the  general  operations,  but  they 
are  not  all  necessary  in  all  cases  ;  and  the 
particular  practice  with  the  several  ores 
of  each  metal  must  vary  according  to  the 
properties  of  the  metal  itself,  and  the  dif- 
ferent substances  it  is  united  with. 

The  extraction  of  metals  from  ores,  in 
the  small  way,  which  is  necessary  to  be 
made,  in  order  to  ascertain  whether  the 
specimens  be  worth  working,  is  called  as- 
saying  or  essaying.  In  these  small  trials, 
the  fusibility  of  the  pounded  ore  is  in- 
creased by  an  addition  of  black  flux, 
which  is  an  impure  alkali,  formed  by  mix- 
ing two  parts  of  tartar  with  one  of  nitre, 
and  setting  them  on  fire.  Metallic  ores 
may  be  very  accurately  assayed  by  solu- 
tion and  precipitation  in  the  humid  way. 
See  the  several  Metals,  also  Assay. 

Most  metals  will  uniformly  mix  with 
each  other;  and  the  specific  gravity  of 
the  compound  is  seldom  such,  as  would 
have  been  deduced  from  the  suppositio» 
of  a  mere  mixture,  or  simple  apposition 
of  parts.  Their  fusibility  is  likewise  great- 
ly changed  by  mixture,  and  according  to 
no  certain  rule  yet  discovered. 

Mixtures  of  metals  are  frequently  call- 
ed  alloys.  But  the  word  alloy,  or  allav, 
is  mostly  used  to  denote  a  portion  of  me- 
tal which  is  added  to  the  precious  metals, 
gold  or  silver. 

Metals  are  mostly  soluble  in  acids, 
with  which  they  form  salts.  When  a  me- 
tal is  added  to  an  acid,  the  general  effect 
produced  is  the  same  as  would  have  ari- 
sen from  the  addition  of  any  other  com- 
bustible substance  to  the  acid  If  an  al- 
kali or  earth  be  added  to  a  metallic  solu. 
tion>  the  metal  falls  to  the  bottom  in  the 


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form  of  an  oxide.  But  if  a  metal,  which 
has  a  stronger  affinity  with  the  acid  than 
the  metal  already  dissolved  has,  be  added 
to  such  a  solution,  the  former  metal  will 
fall  to  the  bottom  in  its  metallic  state,  and 
the  latter  will  be  dissolved  without  caus- 
ing" any  of  the  escape  of  elastic  fluid,  and 
other  appearances,  which  would  have  ta- 
ken place  if  it.  had  been  applied  to  the 
mere  acid;  notwithstanding-  which,  the 
latter  metal,  if  precipitated  by  an  incom- 
bustible substance,  such  as  an  alkali  or 
earth,  will  be  in  the  state  of  an  oxide. 
Phosphorus  likewise  precipitates  them  in 
the  metallic  state. 

It  is  evident,  from  these  facts,  that  the 
action  of  acids  upon  metals  is  similar  to 
that  of  heat  with  access  of  oxigen  ;  and 
of  course  may  be  accounted  for  in  the 
same  manner  as  combustion  itself. 

Metals  are  precipitated  by  each  other 
In  the  same  order,  or  nearly  so,  in  all 
acids.  Hence  it  is  inferred,  that  this  ef- 
fect is  produced  by  the  reaction  of  some 
common  principle,  and  this  is  the  oxigen 
of  the  acids. 

Acids  dissolve  metals  only  in  their  ox- 
ided  state;  and  there  is  a  certain  limit 
near  which  the  solution  is  best  performed. 
If  an  acid  be  of  such  a  nature  as  to  be 
incapable  of  oxiding  a  metal,  it  will  not 
dissolve  it,  though  the  same  acid  would 
dissolve  the  oxide,  if  presented  to  it ;  and 
if  the  oxidation  be  earned  too  far,  the  ox- 
ide will  likewise  be  insoluble.  To  explain 
this  it  may  be  observed,  that  the  simple 
metal  attracts  as  much  oxigen  from  the 
acid  as  is  sufficient  to  convert  itself  into 
an  oxide,  but  not  enough  to  saturate  it 
with  that  principle ;  it  is  therefore  sus- 
pended, in  consequence  of  its  remaining 
weak  attraction  for  the  oxig-en  of  the  acid. 
But  if  the  oxidation  be  complete,  that  is 
to  say,  if  the  affinity  of  the  metal  for  oxi- 
gen be  perfectly  satisfied,  the  remaining 
attraction  of  the  metal  for  oxigen  will 
cease,  and  it  will  be  insoluble. 

The  direct  action  of  alkaline  salts  upon 
metals  is  not  considerable  :  but  several  of 
the  oxides  are  dissolved  by  them  ;  and 
from  these  solutions  the  metal  may  be 
precipitated  in  its  metallic  state,  by  add- 
ing another  metal  more  soluble  in  the  al- 
kali. Sulphur  combines  with  most  of 
them  readily  in  the  way  of  fusion  ;  and 
the  combination  of  sulphur  with  an  alka- 
li is  a  powerful  solvent  of  all  metals  ex- 
cept zinc.  Nitre  heated  with  metals  acts 
in  the  same  manner  as  it  does  with  other 
inflammable  bodies :  it  deflagrates,  and 
the  metals  become  oxided.  The  perfect 
metals  resist  the  action  of  nitre. 

METALLIC  PAINTS,  See  Colour 
Making. 


METALLIC  SPECULUM.  See  Spe- 
culum. 

METALLURGY.  The  characters, 

from  which  mineralogists  pretend  to  as- 
sert the  existence  of  an  ore  in  the  bowels 
of  the  earth,  are  all  equivocal  and  suspi- 
cious. The  savage  aspect  of  a  mountain, 
the  nature  of  the  plants  which  grow  upon 
it,  the  exhalations  which  arise  from  the 
earth,  all  afford  characters  too  doubtful, 
for  a  reasonable  man  to  risk  his  fortune 
upon  such  indications  alone.-  The  dip- 
ping wand,  or  divining  rod,  is  the  fruit  of 
superstition  and  ignorance  ;  and  the  ridi- 
cule, which  has  been  successively  thrown 
upon  this  class  of  impostors,  has  diminish- 
ed their  number ;  at  the  same  time  that 
the  numerous  dupes  of  this  class  of  men 
have  rendered  their  successors  more  pru- 
dent. It  is  nevertheless  used  in  Cornwall, 
in  Great  Britain,  to  this  day. 

The  nature  of  the  stones  which  com- 
pose a  mountain  is  capable  of  furnishing 
some  indications.  We  know,  for  exam-: 
pie,  that  ores  are  seldom  found  in  granite 
and  the  other  primitive  mountains  ;  we 
know  likewise,  that  mountains  of  mo- 
dern formation  contain  them  very  rare- 
ly ;  and  wc  find  them  only  in  secondary 
mountains,  in  which  the  schistus  and  an- 
cient calcareous  stone  are  void  of  all  im- 
pressions of  shells. 

The  presence  of  ponderous  spar,  form- 
ing a  stratum  or  vein  at  the  surface  of  the 
earth,  has  been  considered  by  many  mi- 
neralogists as  a  very  good  indication. 
Chaptal  shows  very  good  reason  for  be- 
lieving, that  this  stone  is  the  same  which 
Becher  has  spoken  of  in  his  works,  under 
the  name  of  Verifiable  Earth,  which  he 
considered  as  a  principle  of  metals  ;  and 
that  it  has  been  very  improperly  taken 
for  quartz  by  his  readers. 

When  we  possess  indications  of  the  ex- 
istence of  an  ore  in  any  place,  we  may 
use  the  borer,  to  confirm  or  destroy  these 
suspicions,  at  a  small  expense. 

It  frequently  happens,  that  the  veins 
are  naked  or  uncovered :  the  mixture  of 
stones  and  metals  forms  a  kind  of  ce- 
ment, which  resists  the  destructive  action 
of  time  longer  than  the  rest  of  the  moun- 
tain ;  and  as  these  parts  of  rocks,  connect- 
ed by  a  metallic  cement,  present  a  stron- 
ger resistance  to  the  action  of  waters, 
which  incessantly  corrode  and  diminish 
mountains,  and  carry  away  their  parts  in- 
to the  sea,  we  frequently  observe  the 
veins  projecting  on  the  sides  of  mountains 
incrusted  with  some  slight  metallic  im- 
pression, altered  by  the  lapse  of  time. 

The  nature  of  an  ore  is  judged  from 
inspection.  A  slight  acquaintance  with 
this  subject  is  sufficient  to  enable  the  ob- 


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scrv  e  to  form  an  immediate  judgment 
of  tlie  nature  of  an  ore.  The  blowpipe 
is  an  instrument,  by  the  assistance  of* 
which  we  may  in  a  short  time  become 
acquainted  likewise  with  the  species 
of  the  ore.  This  knowledge  forms  the 
docimastic  art,  or  docimas'ia.  In  order 
to  make  the  assay  of  an  ore,  in  gene- 
ral, for  all  ores  do  not  require  the  same 
process,  small  pieces  of  the  mineral 
are  examined.  These  are  cleared  from 
foreign  and  stony  substances  as  much  as 
possible.  The  pure  mineral  is  then 
pounded,  and  a  certain  quantity  weighed, 
which  is  torrified  in  a  vessel  larger  and 
fess  deep  than  a  common  crucible.  By 
this  means  the  sulphur,  or  the  arsenic  in 
combination  with  the  metal,  is  dissipated  ; 
and  by  the  loss  of  weight  resulting  from 
the  calcination,  a  judgment  is  formed  of 
the  proportion  of  foreign  volatile  matter  it 
contained. 

The  first  operation  shows  the  propor- 
tion and  quantity  of  sulphur  and  arsenic, 
which  may  be  mixed  with  the  metaU  The 
sulphureous  smell  may  easily  be  distin- 
guished from  the  smell  of  garlic,  which 
characterizes  arsenic.  These  foreign  sub- 
stances mixed  with  the  metal  are  called 
mineralizers. 

In  order  to  obtain  an  accurate  judg- 
ment of  the  weight  of  the  mineralizer, 
the  augmentation  in  weight,  which  the 
metal  has  undergone  in  passing  from  its 
metallic  state  to  that  of  oxide,  must  be 
added  to  the  loss  occasioned  by  the  calci- 
nation. 

Two  hundred  grains  of  this  roasted  ore 
are  then  to  be  taken,  and  mixed  with 
fluxes  capable  of  fusing  and  reducing  it. 
In  this  operation  a  crucible  is  made  use 
of ;  and  a  sufficient  degree  of  heat  being 
applied,  the  metal  is  precipitated  to  the 
bottom  of  the  crucible  in  a  button,  the 
weight  of  which  indicates  the  quantity  of 
metal  contained  in  the  ore. 

These  fluxes  must  be  varied  according 
to  the  nature  of  the  ores  under  examina- 
tion. It  is  necessary  that  they  should  all 
contain  carbon,  to  disengage  the  oxigen 
with  which  these  metals  are  combined, 
liut  the  nature  of  the  flux  must  be  varied 
according  to  the  fusibility  of  the  metal. 
The  following  will  answer  all  these  pur- 
poses : 

1.  The  fusible  material  called  black 
flux  is  made  with  two  parts  of  tartar,  and 
one  part  of  nitre,  melted  together.  The 
carbonaceous  and  alkaline  residue  is  used 
to  reduce  the  ores  of  lead,  copper,  anti- 
mony, &c. 

2.  Two  hundred  grains  of  calcined  bo- 
rax, one  hundred  grains  of  nitre,  twenty 
grains  of  slaked  lime,  and  one  hundred 

VOL,  II. 


grains  of  the  ore  intended  to  be  assayed, 
lbrm  the  flux  of  Scopoli,  which  Chaptal 
found  advantageous  in  the  assay  of  iron 
ores. 

3.  The  vitreous  flux  of  Guyton-Mor- 
veau,  made  with  eight  parts  of  pounded 
glass,  one  of  borax,  and  half  a  part  of 
powder  of  charcoal,  may  be  employed 
for  the  same  purpose. 

4.  Arsenic  and  nitre,  in  equal  parts, 
form  likewise  a  very  active  flux. 

The  neutral  combination  of  oxide  of 
arsenic  and  potash  has  been  used  with 
success  to  fuse  platina. 

As  soon  as  the  existence  of  a  mine  and 
its  nature  and  riches  arc  ascertained,  it  is 
in  the  next  place  necessary  to  be  assured 
of  a  sufficient  abundance  and  continuity 
of  water,  to  answer  the  purposes  of  the 
works.  It  is  likewise  necessary,  to  be  as- 
sured of  possessing  a  sufficient  quantity 
of  wood  or  coal,  and  more  especially  a 
good  director  must  be  procured :  for  a 
poor  mine  well  managed  is  preferable  to 
a  rich  one  ill  conducted. 

Those  preliminary  circumstances  being 
accomplished,  the  most  simple  and  least 
expensive  processes  must  be  employed  in 
extracting  the  mineral  from  the  bowels  of 
the  earth.  For  this  purpose,  shafts  or 
galleries  must  be  dug,  according  to  the 
position  of  the  vein,  and  the  nature  of  its 
situation. 

When  it  is  practicable  to  arrive  at  the 
side  of  the  vein,  and  at  a  certain  depth,  by 
a  horizontal  gallery,  the  works  become 
more  simple  and  ceconomical ;  the  same 
opening  serving  to  draw  off  the  waters, 
and  extract  the  ore.  Galleries  are  then  to 
be  carried  on  to  the  right  and  left ;  and 
shafts  sunk,  which  communicate  with  the 
open  air,  as  likewise  others  carried  down 
into  the  vein.  Galleries  are  likewise  con- 
structed, one  above  the  other,  and  the 
communication  of  the  works  kept  up  by- 
ladders.  When  the  soil  is  friable,  and  de- 
fective in  solidity,  care  must  be  taken 
to  support  it  with  timbers  of  sufficient 
strength  to  prevent  its  falling  in. 

Pickaxes,  wedges,  and  levers  are  used 
to  detach  the  ore,  when  the  rock  is  soft ; 
but  it  is  most  commonly  necessary  to 
employ  gunpowder. 

Want  of  air,  and  the  abundance  of  wa- 
ter, are  almost  always  noxious,  and  de- 
range mine-works.  The  water  is  carried 
off  by  steam-engines,  wind-mill  pumps, 
and  other  suitable  apparatus. 

Currents  of  air  are  produced  by  estab- 
lishing communications  with  the  galleries, 
by  horizontal  apertures.  Furnaces  erect- 
ed on  the  side  of  a  shaft,  to  which  a  long 
tube  is  adapted  at  one  end,  communicat- 
ing with  the  ash-hole,  and  at  the  other 
V 


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plunging  into  the  shaft  to  draw  up  the  air, 
or  ventilators  placed  in  the  same  situa- 
tion, answer  a  similar  purpose.  The  foul 
air  is  destroyed  by  exposing  to  it  a  caus- 
tic lixivium  :  sprinkling  quicklime  about 
the  mine  likewise  produces  the  same  ef- 
fect. 

A  prudent  company  ought  to  extract 
the  largest  possible  quantity  of  ore,  be- 
fore they  determine  upon  constructing 
the  necessary  works  for  the  subsequent 
processes.  We  cannot  see  into  the  bow- 
els of  the  earth.  Appearances  are  often 
deceitful ;  and  we  have  seen  companies 
either  ruined  or  discouraged,  because 
they  had  employed  immense  sums  to  con- 
struct the  necessary  furnaces  to  work  an 
ore,  the  existence  of  which  was  doubtful. 
When  the  proceedings,  in  an  undertaking 
of  this  kind,  are  carried  on  with  proper 
precaution,  and  no  more  expense  is  enter- 
ed into  than  what  the  ore  extracted,  and 
of  a  known  value,  is  capable  of  defray- 
ing, the  probable  losses  are  very  slight, 
even  in  the  poorest  mine. 

The  works  ought  to  be  varied  accord- 
ing to  the  nature  and  state  of  the  mineral. 
It  is  found  in  three  states  : — 1.  In  the  form 
of  a  native  metal :  in  this  case,  nothing 
more  is  necessary  than  to  extract  it  out 
of  the  mine,  to  clear  it  of  the  extraneous 
substances,  and  to  fuse  it.  2.  In  the  form 
of  oxide  :  and  in  this  state  it  is  sufficient, 
if  it  be  sorted  and  fused.  3.  Combined 
with  sulphur  or  arsenic,  in  which  case  it 
must  be  made  to  undergo  some  other  ope- 
rations. 

Although,  in  this  last  case,  the  works, 
subsequent  to  the  extraction,  vary  accord- 
ing to  the  nature  of  the  ore,  there  are 
nevertheless  certain  general  operations, 
to  which  every  kind  of  ore  is  subjected. 

The  first  business  must  be  to  clear  the 
metal  of  the  stony  matter  or  matrix.  For 
this  purpose,  when  the  ore  is  extracted, 
children  are  employed,  who  examine  it, 
and  separate  the  pure  ore,  or  rich  mine- 
ral, from  that  which  is  mixed  with  the 
gangue.  As  in  this  second  quality  the 
stone  is  mixed  with  the  ore,  the  whole  is 
pulverized  by  means  of  a  stamping  mill, 
consisting  of  pestles  of  wood,  shod  with 
iron,  and  armed  with  cocks,  which  are 
raised  by  levers  proceeding  from  the  axis 
of  a  wheel  which  constantly  turns.  The 
mineral  is  by  this  means  crushed  and  pul- 
verized ;  and  a  stream  of  water,  which  is 
made  to  pass  over  it,  carries  away  both 
the  metallic  and  stony  particles ;  the  for- 
mer being  deposited  in  the  first  vessels 
through  which  the  water  is  made  to  cir- 
culate, while  the  latter,  or  stony  part,  is 
carried  to  a  greater  distance,  on  account 
of  its  comparative  lightness. 


This  pulverized  ore  is  called  sclich; 
and  in  order  to  separate  all  the  earthy 
parts,  it  is  washed  upon  tables  slightly  in- 
clined, over  which  a  constant  stream  of 
water  is  made  to  flow.  The  sclich  is 
agitated  with  brooms  ;  the  water  carries 
away  all  the  fragments  of  stone,  and 
leaves  the  pure  ore  upon  the  table. 

The  roasting  of  the  mineral  succeeds 
the  washing.  In  this  operation,  the  mine- 
rals zer  is  carried  off.  Fire  is  always  the 
agent  made  use  of  Sometimes  the  pound- 
ed mineral  is  disposed  in  piles  upon  heaps 
of  fuel,  which,  being  set  on  fire,  heat  the 
ore  strongly,  and  drive  off  the  mineral- 
izer.  This  calcination  possesses  the  dou- 
ble advantage  of  disposing  the  metal  fur 
fusion,  as  well  as  clearing  it  of  the  mine- 
ralizing substance  When  the  ore  is  more 
friable,  it  is  spread  out  in  a  reverberato^y 
furnace  ;  and  the  flame  which  reverberates 
upon  it  deprives  it  of  its  mineralizer,  at 
the  same  time  that  it  partly  fuses  it. 

Mr  Exchaquet  has  proposed  to  destroy 
the  sulphur  by  nitre  in  assays.  This  pro- 
cess is  excellent  for  copper  ores :  the 
quantity  of  nitre  varies  according  to  the 
quantity  of  sulphur ;  but  there  is  no  dan- 
ger of  adding  too  much.  In  this  opera- 
tion the  mixture  is  thrown  into  an  ignited 
crucible,  and  kept  at  a  moderate  heat  for 
some  minutes. 

The  fusion  is  effected  in  furnaces,  ex- 
cited by  a  current  of  air,  kept  up  by 
means  of  large  bellows,  or  a  machine  call> 
ed  a  trompe 

METALLIC  LEAVES  or  Foils.— It 
is  customary  to  place  thin  foils,  or  leaves 
of  metal  under  precious  stones,  to  make 
them  look  transparent,  and  to  give  them 
an  agreeable  colour,  either  deep  or  pale  : 
thus,  if  a  stone  is  to  be  of  a  pale  colour, 
put  a  foil  of  that  colour  under  it;  again, 
if  you  would  have  it  deep,  lay  a  dark  one 
under  it :  besides,  as  the  transparency  of 
gems  discovers  the  bottom  of  the  ring 
they  are  set  in,  artificers  have  found  out 
those  means  to  give  the  stone  an  addi- 
tional beauty. 

These  foils  are  made  either  of  copper 
or  gold,  or  gold  and  silver  together  :  we. 
shall  first  mention  those  made  of  cop- 
per only,  which  are  generally  known  by 
the  name  of'Nuremburg  or  German  foils. 

Procure  the  thinnest  copper  plates,  the 
thinner  they  are  the  less  trouble  they  will 
give  in  reducing  them  to  a  finer  substance: 
beat  these  plates  gently  upon  a  well  po- 
lished anvil,  with  a  polished  hammer,  as 
thin  as  possible  ;  but  before  you  go  about 
this  work,  take  two  iron  plates,  about  six 
inches  long,  and  as  wide,  but  no  thicker 
than  writing-paper ;  bend  them  so  as  to 
fit  one  on  the  other ;  between  these  neal 


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the  copper  you  design  to  hammer  for  the 
foils,  to  prevent  ashes,  or  other  impuri- 
ties getting'  to  it;  then,  taking  them  out, 
shake  the  ashes  from  them,  and  hammer 
the  copper  until  cool.  Then  take  your 
ibils  to  the  anvil,  and  beat  them  until  they 
become  very  thin,  and  whilst  you  beat 
one  number,  put  in  another  between  the 
irons  to  neal ;  this  you  may  repeat  eight 
times,  until  they  are  as  thin  as  the  work 
requires.  You  must  have  a  pipkin  with 
water  at  hand,  in  which  put  tartar  and 
salt,  of  each  an  equal  quantity;  boil,  and 
put  the  foils  in,  and  stir  them  continually, 
until,  by  boiling,  they  become  white:  then 
take  them  from  the  fire ;  wash  them  in 
clean  water  ;  dry  them  with  a  clean  fine 
rag,  and  give  them  another  hammering 
on  the  anvil,  until  they  are  fit  for  your 
purpose. 

N.  B  Care  must  be  taken  in  the  ma- 
nagement of  this  work,  not  to  give  the 
foils  too  much  heat,  to  prevent  their  melt- 
ing ;  neither  must  they  be  too  long  boiled, 
for  fear  of  attracting  too  much  salt. 

How  to  polish  and  colour  foils. — Take 
a  plate  of  the  best  copper,  one  foot  long, 
and  about  five  or  six  inches  wide,  polish- 
ed to  the  greatest  perfection :  bend  this 
to  a  convex  shape,  lengthwise,  and  fix  it 
to  a  bench,  or  table  :  then  take  some  whit- 
ing, and  having  laid  some  on  the  roll,  and 
wetted  the  copper  all  over,  lay  your  foils 
upon  it,  and  with  a  polish-stone  and  the 
whiting,  polish  your  foils,  until  they  are 
as  bright  as  a  looking-glass ;  then  dry 
them  between  a  fine  rag,  and  lay  them  up 
secure  from  the  dust  We  shall  now  show 
how  these  foils  are  coloured. 

Lay  the  foils  upon  a  pair  of  tongs ;  hold 
them  over  the  hole  that  is  at  the  top  of 
the  furnace,  which  is  to  be  used  so  that 
the  fumes  of  the  coals  may  come  in  con- 
tact and  move  them  about  till  they  arc  of 
a  brownish  violet  colour.  If  the  colour  is 
to  be  of  a  sky  blue,  then  put  the  foils  upon 
the  tongs  as  before  ;  and  whilst  you,  with 
one  hand,  are  holding  the  foils' over  the 
holes,  fling,  with  the  other,  some  light 
fuel  upon  the  live  coals  in  the  funnel,  and 
with  a  red-hot  poker  press  it  down,  to 
drive  the  smoke  through  the  holes  of  the 
oven,  which  gives  them  a  fine  sky  colour : 
but  you  must  have  your  eyes  very  quick 
upon  them,  and,  as  soon  as  you  see  that 
they  have  attracted  the  colour  you  de- 
sign, take  them  away  from  the  oven,  to 
prevent  their  changing  to  some  other  co- 
lour ;  if  you  would  have  your  foils  of  a 
sapphire  "blue,  then  first  silver  them  over; 
which  is  done  in  this  manner : 

Take  a  little  silver  and  dissolve  it  in 
aqua-fortis;  when  dissolved,  put  spring 
water  to  it ;  fling  thin  bits  of  copper  into 


it,  and  the  water  will  look  troubled,  and 
the  silver  precipitate  and  hang  to  the  cop- 
per; pour  off  that,  wash  the  silver  with 
water,  and  let  it  dry  in  the  sun  ;  when 
dry,  grind  it  on  a  porphyry  :  then  take  one 
ounce  of  tartar,  and  as  much  of  common 
salt ;  mix  and  grind  them  all  together, 
till  they  are  well  mixed;  fling  this  pow- 
der upon  the  thin  foils,  and  rub  them  with 
your  finger  backwards  and  forwards,  and 
it  will  silver  them ;  then  lay  them  upon 
the  polisher,  pour  water  over  them,  and 
some  of  the  powder,  and  rub  it  with  your 
thumb  till  they  are  as  white  as  you  would 
have  them:  polish  them,  and  holding 
them  over  the  smoke,  they  will  take  a 
fine  dark  blue. 

METALLIC  POWDER  (Nuremberg.) 
Mix  together  clean  filings  of  copper,  brass, 
iron,  steel,  and  other  metals.  Put  each  of 
them  separately  into  an  iron  vessel,  and 
heat  them  till  they  change  colour.  The 
degree  of  heat  can  only  be  regulated  by 
trial.  Take  these  to  a  good  flatting-mill, 
furnished  with  a  funnel  at  top,  and  pass 
these  filings  through  it,  and  you  will  pro 
cure  a  most  beautiful  sparkling  powder 
of  all  sorts  of  lively  colours. 

METEOROLOGY.— As  the  science  of 
meteorology  is  important  to  mankind,  we 
have  thought  it  better  to  give  the  follow- 
ing short  treatise,  for  which  we  are  in- 
debted to  Nicholson. 

The  state  and  condition  of  the  great 
fluid  mass,  in  which  we  breathe,  and  the 
changes  which  take  place  therein,  are  ob- 
jects of  no  small  importance  to  the  che- 
mical philosopher.  Among  the  variety  of 
experiments  on  permanently  elastic  fluids, 
it  is  found,  that  most  of  them  are  capable 
of  uniformly  mixing  together,  when  their 
nature  is  such  as  not  to  act  perceptibly 
upon  each  other.  But  in  the  extensive 
mass  of  the  atmosphere,  it  seems  likely, 
that  considerable  separations  of  its  com- 
ponent parts  take  place,  in  consequence 
of  their  different  specific  gravities.  This 
supposition  is  countenanced  by  several 
optical  phenomena,  such  as  the  double 
appearance  of  head  lands.  In  this  way 
some  writers  account  for  the  appearance 
of  the  aurora  borealis,  shooting  stars,  and 
other  similar  appearances,  which  they 
suppose  to  consist  of  hydrogen  gas,  occu- 
pying the  upper  region  of  the  atmosphere, 
and  fired  by  electricity.  It  is  a  remarka- 
ble circumstance,  that  most  of  these  fiery 
appearances  happen  at  an  elevation,  which 
is  geometrically  determined  to  be  almost 
twice  as  great  as  that  which  astronomical 
writers,  by  deductions  founded  on  the  re- 
fraction of  the  light  of  the  heavenly  bo- 
dies, and  the  law  of  dilatation  of  air  near 
the  surface  of  the  earth,  have  assigned  as 


MET 


MET 


the  sensible  limit  of  the  atmosphere. 
Hence  it  should  follow,  that  the  elasticity 
of  the  upper  parts  exceeds  that  of  the 
lower;  which  affords  no  inconsiderable 
presumption,  that  this  upper  part  is  chief- 
ly composed  of  such  air  as  we  know  to 
be  the  most  elastic,  namely,  hydrogen: 
The  composition  of  water,  out  of  the  two 
ingredients,  oxigcn  and  hydrogen,  has  al- 
so afforded  ground  for  meteorological  in- 
duction. It  lias  been  concluded,  that  wa- 
ter is  not  only  condensed  and  precipitated 
by  the  agency  of  electricity,  in  thunder 
storms,  but  that  it  is  likewise  composed 
out  of  its  elements  by  the  combustion  of 
these  two  airs,  in  every  case  where  at- 
mospherical corruscation  is  exhibited. 

The  phenomena  of  winds,  though  chief- 
ly depending  on  the  hydrostatical  change 
in  the  density  of  the  air  by  alteration  of 
temperature,  well  deserve  the  attention 
of  the  chemist.  The  effect  of  furnaces, 
the  clearing  of  laboratories,  burial  vaults, 
houses  of  office,  mines,  and  other  exca- 
vations, from  noxious  effluvia,  are  all  go- 
verned by  general  laws  of  the  same  na- 
ture, as  those  which  cause  the  currents  of 
air  around  us.  Even  the  sudden  and  fre- 
quently impetuous  current  of  air,  which 
accompanies  a  fall  of  rain,  or  squall, 
though  it  is  merely  produced  by  the  me- 
chanical action  of  the  falling  drops  of  wa- 
ter, has  afforded  ground  for  useful  medi- 
tation. There  is  no  doubt,  but  we  are  in- 
debted to  considerations  on  this  natural 
appearance  for  the  cheap  and  useful 
blowing-machine,  which  the  French  call 
a  trompe. 

It  may  seem  at  first  sight,  as  if  observa- 
tions on  the  standing  of  the  barometer 
and  thermometer  were  of  no  very  imme- 
diate use  to  the  practical  chemist.  But 
if  it  be  considered,  that  the  effect  of  an 
air  furnace  depends  on  the  difference  of 
the  density  of  the  air  in  the  chimney,  and 
that  which  enters  the  ash-hole ;  and  that 
the  mere  difference  indicated  by  the  ba- 
rometer amounts  to  one  fifteenth  part,  in 
its  extremes,  of  the  whole  quantity  of  the 
external  air,  in  a  given  place  ;  not  to  men- 
tion the  effect  pointed  out  by  the  ther- 
mometer ;  it  will  not  appear  strange,  that 
these  causes  should  greatly  influence  the 
results  in  metallurgical  operations,  and 
be  very  perceptible  in  the  burning  of  our 
culinary  fh-es.  The  philosophical  chemist 
is  no  less  interested  in  the  state  of  the  air, 
as  shown  by  these  instruments.  ,For  it 
cannot  but  be  of  great  consequence  to  his 
deductions,  to  know  the  external  pres- 
sure, which  is  constantly  acting  upon  the 
elastic  fluids  he  may  either  weigh  or  mea 
sure.    If  this  and  the  temperature  be  not 


carefully  attended  to,  he  will  scarcely  find 
any  two  results,  made  at  distant  times, 
agree. 

The  presence  of  moisture,  or  rather  its 
disposition  to  be  absorbed,  or  given  out, 
as  shown  by  the  hygrometer,  must  be  of 
considerable  importance.  It  affects  the 
elasticity  of  every  kind  of  air,  and  there 
is  no  doubt  but  combustion  and  its  pro- 
ducts will  vary  accordingly  as  it  is  main- 
tained by  an  air,  which  is  moister  or  more 
dry.  It  is  probable,  that  the  quantities  of 
finery  cinder  afforded  by  iron  may  vary 
from  this  cause. 

The  effects  of  solution  and  precipita- 
tion, analagous  to  what  happens  in  denser 
fluids,  have  been,  perhaps  too  fancifully, 
delineated  among  the  atmospheric  chan- 
ges. But  there  is  every  reason  to  think, 
that,  as  our  knowledge  of  the  great  sys- 
tem of  nature  shall  improve,  the  play  of 
the  chemical  affinities  will  show  itself 
more  evidently  in  the  atmosphere. 

Within  these  few  years  the  attention  of 
chemists  has  been  particularly  called  to  a 
very  remarkable  phenomenon  in  this  de- 
partment of  science.  Reports  of  stones 
falling  from  the  atmosphere  had  been  ge- 
nerally discredited,  from  the  improbability 
of  the  fact.  But  the  progress  lately  made 
in  science  has  established  so  many  facts 
contrary  to  long  received  opinions,  and 
so  far  extended  the  limits  of  possibility, 
that  men  are  become  much  more  cautious 
of  peremptorily  refusing  to  credit  a  thing', 
merely  on  account  of  its  seeming  impro- 
bable ;  and  are  inclined  to  investigate,  be- 
fore they  deny.  Tims  an  inquiry  has  been 
instituted,  audit  appeas,  that  such  oc- 
currences have  been  recorded  from  time 
to  time  from  a  remote  period,  that  they 
have  happened  in  various  quarters  of  the 
globe,  that  the  testimony  is  corroborated 
by  circumstances,  and  that  in  many  re- 
cent instances  it  appears  incontrovertible. 

It  is  remarkable,  that  all  the  stones,  at 
whatever  period,  or  in  whatever  part  of 
the  world,  they  may  have  fallen,  have  ap- 
peared, as  far  as  they  have  been  examin- 
ed, to  consist  of  the  same  substances  ;  and 
to  have  nothing  similar  to  them,  not  only 
among  the  minerals  in  the  neighbourhood 
of  the  places  where  they  were  found,  but 
among  all  that  have  hitherto  been  disco- 
vered in  our  earth,  as  far  as  men  have 
been  able  to  penetrate.  For  the  chemi- 
cal analysis  of  a  considerable  number  of 
specimens,  we  are  particularly  indebted 
to  Mr.  Howard,  as  well  as  to  Klaproth 
and  Vauquelin,  and  a  precise  mineralogi- 
cal  description  of  them  has  been  given  by 
the  Count  de  Bournon  and  others. 

They  are  all  covered  with  a  thin  crust 


MET 


MEZ 


of  a  deep  black  colour,  they  are  without 
gloss,  and  their  surface  is  roughened  with 
small  asperities.  Internally  they  are  gray- 
ish, and  of  a  granulated  texture,  more  or 
less  fine.  Four  different  substances  are 
interspersed  among  their  texture,  easily 
distinguished  by  a  lens.  The  most  abun- 
dant is  from  the  size  of  a  pin's  head  to 
that  of  a  pea,  opake,  with  a  little  lustre 
like  that  of  enamel,  of  a  gray  colour, 
sometimes  inclining  to  brown,  and  hard 
enough  to  give  faint  sparks  with  steel. 
Another  is  a  martial  pyrites,  of  a  reddish 
yellow  colour,  black  when  powdered,  not 
very  firm  in  its  texture,  and  not  attracta- 
ble by  the  magnet.  A  third  consists  of 
small  particles  of  iron  in  a  perfectly  me- 
tallic state,  which  give  to  the  mass  the 
quality  of  being  attracted  by  the  magnet, 
though  in  some  specimens  they  do  not 
exceed  two  per  cent,  of  the  whole  weight, 
while  in  others  they  extend  to  a  fourth. 
These  are  connected  together  by  a  fourth 
of  an  earthy  consistence  i»most,  so  that 
they  may  be  broken  to  pieces  by  the  fin- 
gers with  more  or  less  difficulty.  The 
black  crust  is  hard  enough  to  emit  sparks 
with  steel,  but  may  be  broken  by  a  stroke 
with  a  hammer,  and  appears  to  possess 
the  properties  of  the  very  attractable 
black  oxide  of  iron.  Their  specific  gravi- 
ty varies  from  3.352  to  4.281. 

The  crust  appears  to  contain  nickel 
united  with  iron,  but  Mr.  Hatchett  could 
not  determine  its  proportion.  The  py- 
rites he  estimates  at  iron  .68,  sulphur  .13, 
nickle  .06,  extraneous  earthy  matter  .13. 
In  the  metallic  particles  disseminated 
through  the  mass,  the  nickel  was  in  the 
proportion  of  1  part,  or  thereabout,  to  3 
of  iron.  The  hard  separate  bodies  gave 
silex  .50,  magnesia  .15,  oxide  of  iron  .34, 
oxide  of  nickel  0.25  :  and  the  cement,  or 
matrix,  silex  .48,  magnesia  .18,  oxide  of 
iron  .34,  oxide  of  nickle  .025.  The  in- 
crease of  weight  in  both  these  arose  from 
the  higher  oxidation  of  the  iron.  These 
proportions  are  taken  from  the  stones  that 
fell  at  Benares  on  the  19th  of  December, 
1798. 

The  solitary  masses  of  native  iron,  that 
have  been  found  in  Siberia,  Bohemia,  Se- 
negal, and  South  America,  likewise  agree 
in  the  circumstance  of  being  an  alloy  of 
iron  and  nickel ;  and  are  either  of  a  cellu- 
lar texture,  or  have  earthy  matter  disse- 
minated among  the  metal.  Hence  a  simi- 
lar origin  has  been  ascribed  to  them. 

Laugier,  and  afterward  Thenard,  found 
chrome  likewise,  in  the  proportion  of 
about  one  per  cent,  in  different  meteoric 
stones  they  examined ;  but  they  appear 
not  to  have  analysed  the  parts  separately. 

In  all  the  instances  in  which  these 


stones  have  been  supposed  to  fall  from  the 
clouds,  and  of  which  any  perfect  account 
has  been  given,  the  appearance  of  a  lumi- 
nous meteor,  exploding  with  loud  noise, 
has  immediately  preceded,  and  hence 
has  been  looked  to  as  the  cause.  The 
stones  likewise  have  been  more  or  less 
hot,  when  found  immediately  after  their 
supposed  fall.  Different  opinions,  howe- 
ver, have  been  entertained  on  this  sub- 
ject, which  is  certainly  involved  in  much 
difficulty.  Some  philosophers  imagine 
them  to  be  formed  in  the  atmosphere  by 
a  sudden  condensation  of  the  elements  of 
their  component  parts  :  others,  that  they 
already  existed  on  the  spot  where  they 
were  found,  and  were  merely  struck  by 
electric  discharge  :  and  professor  Proust 
has  suggested,  that  they  might  be  torn 
from  the  polar  regions  by  the  meteor- 
Some  have  supposed  them  to  be  merely 
projected  from  volcanoes :  while  others 
have  suggested,  that  they  might  be 
thrown  from  the  moon  ;  or  be  bodies  wan- 
dering through  space,  and  at  length 
brought  within  the  sphere  of  attraction  of 
our  planet. 

We  shall  conclude  this  article  with  the 
instances  that  have  occurred  during  the 
present  century.  On  the  26th  of  April, 
1803,  a  shower  of  stones,  weighing  from 
18 lbs.  to  |  of  an  ounce,  and  supposed  to 
be  two  or  three  thousand  in  number,  fell 
in  the  neighbourhood  of  TAigle,  in  Nor- 
mandy, on  a  space  about  six  miles  long 
and  two  broad.  On  the  4th  of  July,  a  stone 
struck  a  house  at  East  Norton,  in  England, 
with  an  explosion,  by  which  the  house  was 
much  damaged.  On  the  8th  of  Septem- 
ber, a  stone  fell  near  Apt,  in  the  country 
of  Avignon.  On  the  13th  of  December, 
a  stone  fell  on  a  barn  at  a  small  village  in 
Germany,  and  broke  the  rafters  of  the 
roof.  On  the  5th  of  April,  1804,  a  stone 
fell  at  Possie,  about  three  miles  from 
Glasgow.  And  on  the  15th  of  March, 
1806,  one  fell  at  Valence,  in  the  arron- 
dissement  of  Alais,  in  France. 

Professor  Silliman  examined  a  meteoric 
stone  which  fell  in  Connecticut,  and  the 
result  was  the  same. 

METHEGELIN. — A  fermented  bever- 
age made  from  honev  and  water. 

MEZZOTINTO  SCRAPING.  See  En- 
graving. 

MEZZOTINTO  PRINTS,  the  art  of 
painting  -with  oil  colours. — Paste  the  print 
on  a  piece  of  clean,  white,  crown  glass, 
which  must  be  of  the  same  dimension  with 
the  print ;  this  is  done  in  the  following 
manner:  first,  take  the  mezzotinto  print; 
and  draw  it  through  clean  water ;  repeat 
this  six  or  eight  times,  once  every  hour ; 
then  lay  it  between  some  moistened  prim  - 


MIL 


MIL 


ing-paper,  and  let  it  there  remain  all  night : 
the  next  day  set  the  glass  before  the  fire, 
and,  when  it  is  warm,  take  some  turpen- 
tine in  a  tea-cup,  or  a  pipkin,  and  warm 
it  over  a  clear  fire  ;  then  take  a  large  brush 
of  hog's  hair,  and  dipping  it  into  the  tur- 
pentine, spread  it  smooth  and  even  upon 
the  glass  :  then,  the  print  being  thorough- 
ly soaked,  take  it  out  from  between  the 
paper,  and  lay  it  gently  on  the  glass,  be- 
ginning at  one  end,  and  proceeding  gra- 
dually to  press  it  gently  down  ;  and  thus 
you  go  on  till  the  whole  print  lies  close, 
and  you  perceive  no  wind-babbles  between 
the  paper  and  the  glass.  This  being  done, 
with  your  fingers  roll  and  rub  off  all  the 
paper,  till  you  see  no  remains  of  it,  but 
only  the  print  on  the  glass  :  thus  the  most 
difficult  task  of  the  work  is  done.  If  the 
print  is  on  a  stubborn  paper,  then  roll  it 
Tip,  tie  it  round  with  thread,  and  boil  it 
in  fair  water,  and  that  will  make  it  fit  for 
peeling.  When  the  glass  with  the  im- 
pression on  it  is  thoroughly  dry,  have  the 
oil-colours,  of  all  the  different  sorts  that 
painters  use,  placed  on  a  palette,  and 
paint  the  several  parts  with  such  as  are 
suitable  to  them,  on  the  back  of  the  print, 
which  will  guide  you  by  the  out-line, 
where  to  break  off  one,  and  to  begin  ano- 
ther, the  shadows  of  the  print  will  make 
the  shadow  of  your  colour.  But  if  you 
choose  to  have  one  deeper  shadow  added 
to  what  is  already  upon  the  glass,  then 
let  them  be  laid  on  first,  and  the  lighter 
colour  after,  which  you  may  blend  toge- 
ther, so  as  to  imitate  a  real  painting. 
Whatever  colours  you  lay  on,  let  them 
be  strong-bodied,  that  they  may  make  the 
better  appearance  on  the  face  of  the  glass. 

MILD  ALKALIS,  or  EARTHS— The 
alkalis  and  lime  are  usually  met  with  in 
combination  with  carbonic  acid.  Heat 
expels  this  substance  from  lime,  and  the 
alkalis  are  deprived  of  it  by  the  superior 
attraction  of  pure  quick  lime,  with  which 
they  are  treated  for  this  purpose.  These 
practical  operations  were  performed  long- 
before  the  existence  and  properties  of  car- 
bonic acid  were  well  ascertained.  The  al- 
kalis and  lime,  when  combined  with  car- 
bonic acid,  obtained  the  name  of  mild, 
from  their  slight  action  upon  organized 
substances,  compared  with  their  action 
when  deprived  of  it.  In  the  latter  state, 
they  were  said  to  be  caustic.  The  terms 
caustic  and  mild  are  still  frequently  ap- 
plied to  the  alkalis,  and  also  to  lime,  mag- 
nesia, and  barvtes. 

MILITARY  FEATHERS.  The.mahu- 
facture  of  military  feathers  is  carried  on 
to  a  considerable  extent  in  the  United 
States ;  but  none  in  the  country  appear 
to  understand  the  business  so  well,  in- 


cluding the  branch  of  dyeing,  as  Mr.  Lit- 
tleboy  and  Mr.  Tucker,  who  have  ob- 
tained much  celebrity  in  this  city. 

Before  the  feathers  come  into  the  hands 
of  the  person  who  makes  them  up  for  sale, 
they  undergo  several  operations.  They 
are  curled,  either  by  being  baked,  or  by 
means  of  hot  irons  ;  and  when  necessarv, 
they  are  also  dyed. 

The  feathers  principally  in  use  are  those 
of  the  ostrich,  heron,  the  common  cock, 
swan,  peacock,  and  goose  :  of  these,  some 
are  adapted  to  plumes,  others  are  fitted 
for  ornaments  to  the  human  head:  to 
some  we  are  indebted  for  the  beds  on 
which  we  lie,  and  to  others  for  the  pens 
with  which  we  write. 

Military  feathers  are  chiefly  made  of  the 
hackle  feathers  as  they  are  called ;  these 
are  plucked  from  the  neck  of  the  cock. 
The  feathers  of  this  bird  are  in  great  de- 
mand :  his  neck  and  back  are  clothed  with 
long  streaming  feathers,  intermixed  with 
orange,  black,  and  yellow ;  his  tail  is  made 
up  of  stiff  feathers,  with  two  larg-e  ones 
waving  over  the  rest  in  form  of  a  sickle. 

The  plumage  of  the  wonderful  Indian 
cock  is  very  beautiful  and  consists  of  five 
different  colours,  viz.  the  black,  white, 
green,  red,  and  blue  ;  and  the  tail  is  made 
up  of  twelve  very  beautiful  feathers  But 
ostrich  feathers  are  the  most  valuable ; 
in  their  natural  state  they  are  mostly  black 
and  white  :  the  largest  feathers  are  at 
the  extremities  of  their  wings  and  tails. 

The  feathers  cf  the  ostrich  require  dye- 
ing and  dressing  before  they  can  be  used 
as  ornaments. 

Plume,  or  plumage,  denotes  the  feathers 
of  birds,  which  are  frequently  worn  by 
military  men,  and  females,  as  ornaments 
to  the  head-dress;  a  custom  originally 
derived  from  barbarous  nations. 

White  plumage  may  be  effectually 
bleached  by  dipping  it  in  the  oxygenated 
muriatic  acid,  or  bleaching  liquor  of  Ber- 
thollet ;  and,  this  can  be  easil)  pro- 
cured, by  simply  immersing  it  for  a  few 
hours  in  pure  water  acidulated  with  oil  of 
vitriol,  in  the  proportion  of  six  or  eight 
drops  of  the  latter,  to  every  ounce  of  the 
former ;  then  drying  the  feathers  in  the 
sun,  or  at  a  distance  from  a  fire. 

The  bleaching  of  plumes  may  be  effect- 
ed in  a  very  simple  manner,  without  much 
difficulty,  in  the  following  manner : — Mix 
in  a  bason  equal  parts  of  common  salt  and 
red  lead,  or  in  preference  manganese  of 
the  shops :  to  this  mixture  add  about  half 
its  weight  of  oil  of  vitriol  previously  dilu- 
ted with  a  small  quantity  of  water.  Take 
the  plume  to  be  whitened,  and,  after  wet- 
ting it  in  water,  expose  it  to  the  fumes  or 
gas  arising  from  the  mixture.    In  half  an 


1 


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hour  or  less  time,  the  feather  will  become 
beautifully  white.  We  have  tried  this 
plan,  and,  from  its  simplicity,  we  recom- 
mend it  to  feather  workers.  From  the 
nature  of  the  materials  it  is  obvious,  that 
the  oil  of  vitriol  disengages  the  marine 
acid  from  the  common  salt,  which  then 
becomes  oxygenized  from  t  he  red  lead  or 
manganese.  The  gas  therefore  disen- 
gaged, is  the  oxymuriatic.  By  combin- 
ing with  the  water  on  the  feather,  it  forms 
liquid  oxymuriatic  acid,  and  discharges 
the  colour. 

Variegated  plumage  may  be  cleaned 
and  restored  to  its  former  brightness,  by 
gently  wiping  it  with  a  soft  sponge  dipped 
in  spirits  of  wine  ;  and,  after  it  has  been 
gradually  dried,  by  moistening  the  downy 
part  with  a  filtered  solution  of  gum-arabic, 
or  tragacanth  ; — then  cautiously  exposing 
the  tops  and  sides  to  the  heat  of  a  bright 
fire,  in  orter  to  curl  their  extremities. 

With  respect  to  the  art  of  dyeing  fea- 
thers, we  refer  to  the  article  Dyeing 

MILK.  This  fluid,  the  next  in  im- 
portance of  all  the  animal  liquors  to  blood, 
has  been  examined  very  largely  by  diffe- 
rent chemists,  and  its  analysis  is  curious 
and  important. 

Milk  is  a  white  opake  fluid,  varying  in 
hue  from  a  yellowish  to  a  blueish  tint,  of 
a  soft  somewhat  unctuous  feel,  and  a 
sweetish  and  grateful  taste.  It  frequently 
is  altered,  in  taste  and  smell,  and  some- 
times too  in  colour,  by  the  nature  of  the 
aliment  which  the  animal  takes.  The 
specific  gravity  of  milk  varies  according 
to  the  animal  that  produces  it,  the  food, 
and  other  circumstances.  The  gravity  of 
cows  milk  is  about  1.0203  according  to 
Brisson,  and  this  is  the  lightest  next  to 
human  milk.  Sheeps  milk,  which  is  hea- 
vy, weighs  1.0409. 

The  chemical  composition  of  this  fluid 
is  the  same  in  all  animals,  as  far  as  has 
been  examined  ;  that  is,  all  milks  consist 
of  the  same  substances  in  intimate  combi- 
nation, but  the  relative  proportion  of  these 
substances  is  probably  not  the  same  in  any 
two  animals,  and  is  so  remarkably  diffe- 
rent in  some,  as  to  be  obvious  to  common 
observers.  In  a  general  view  milk  may 
be  said  to  be  composed  of  the  following 
ingredients. 

1.  Of  the  caseous  or  curd)'  matter,  which 
is  separable  from  milk  by  various  means, 
and  particularly  by  rennet,  and  which 
when  collected  and  condensed  by  pres- 
sure forms  cheese. 

2.  Of  a  true  animal  oil,  butter,  which 
is  separable  from  the  cream  chiefly  by 
agitation. 

3.  Of  a  sweet  watery  fluid,  the  serum 
or  whey,  which  generally  contains  a  good 


deal  of  the  two  former  ingredients  dis- 
solved, and  also  holds  a  quantity  of  sac- 
charine matter,  of  animal  jelly,  ofmuriat 
of  soda,  and  potash,  and  some  phosphats. 

Milk  when  moderately  heated  swells 
and  froths  considerably,  and  at  about 
200°  of  heat  it  boils.  At  the  same  time 
there  forms  on  the  surface  a  tough  dry- 
pellicle,  which  when  removed  is  succeeded 
by  another,  and  so  on  successively.  This 
skin  is  the  same  as  the  curd  or  caseous 
matter  obtained  by  the  common  means, 
and  if  the  process  is  continued  for  a  great 
length  of  time,  all  the  curd  may  be  sepa- 
rated in  this  form,  and  a  watery  liquid 
alone  will  remain 

If  milk  is  evaporated  to  dryness  there 
remains  a  solid  yellowish  extract,  known 
abroad  by  the  name  of  franc hip ane,  and 
formerly  used  in  medicine.  If  the  vapour 
diatiiletl  from  boiling  milk  be  condensed 
in  a  proper  receiver,  it  forms  a  clear  li- 
quor of  a  faintish  taste,  which  after  long 
standing  becomes  muddy  and  putrefies. 

The  coagulation  of  milk  is  one  of  the 
most  important  changes  which  it  under- 
goes, and  is  effected  by  a  variety  of  me- 
thods. All  the  acids  coagulate  milk,  al- 
cohol and  all  vinous  liquors  do  the  same, 
and  also  several  vegetables.  But  the 
speediest  and  most  perfect  coagulation  is 
effected  by  rennet,  or  an  infusion  of  the 
stomach  of  calves,  pickled  and  salted, 
which  is  the  substance  used  in  making 
cheese.  The  gastric  juice  of  all  animals 
aiso  produces  the  same  effect,  and  hence 
coagulation  is  the  first  process  in  the  na- 
tural digestion  of  this  fluid. 

Coagulation  is  the  most  convenient  me- 
thod of  analyzing  milk,  and  it  is  thereby 
resolved  into  two  principal  portions,  the 
coagulum  or  curd,  and  the  whey.  The 
analysis  of  each  of  these  substances  gives 
the  following  results. 

Whey  prepared  by  rennet  (which  is  on 
the  whole  the  best  substance  for  coagu- 
lating milk  for  chemical  analysis)  when 
filtered  and  clarified  is  a  limp*id  yellowish 
fluid,  of  a  sweetish  and  rather  saline  taste, 
agreeable  to  most  palates.  Its  specific 
gravity  is  somewhat  less  than  that  of  the 
milk  from  which  it  is  procured.  Whey, 
when  gently  evaporated  to  the  consistence 
of  a  syrup  and  allowed  to  cool  undisturb- 
ed, deposits  a  singular  crystalline  sweet- 
ish matter  called  sugar  of  milk,  which  is 
prepared  pretty  largely  in  some  of  the 
Swiss  cantons,  and  is  used  for  cu  inary 
and  medicinal  purposes.  To  prepare  it, 
fresh  whey  from  skimmed  milk  is  boiled 
down  to  the  thic  kness  of  syrup,  and  then 
poured  into  earthen  pots,  where  it  solidi- 
fies and  dries  in  the  sun  ;  this  mass,  which 
is  brown  and  impure,  is  refined  by  re-so 


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lution,  clarification  with  white  of  egg,  and 
another  evaporation,  after  which  it  con- 
cretes into  white  rhomboidal  crystals. 

Sugar  of  milk  when  pure  is  a  white 
crystalline  substance,  or  a  sweetish  and 
rather  mawkish  taste,  soluble  in  four 
parts  of  boiling  water  and  about  twelve 
of  cold.  When  strong-ly  heated  it  turns 
brown,  swells  up  and  exhales  the  strong 
pungent  vapour  of  burnt  sugar,  and  final- 
ly leaves  a  black  coal  holding  about  one- 
thirtieth  of  its  weight  of  salt,  composed 
according  to  Rouelle,  of  three  parts  mu- 
riat  of  potash  and  one  part  carbonat  of 
potash. 

The  phenomena  attending  the  coagu- 
lation of  milk  by  acids  and  by  alcohol  will 
be  soon  noticed;  that  by  rennet  is  under- 
stood at  present. 

The  curd  of  milk  prepared  by  rennet, 
to  be  chemically  pure,  should  be  made  of 
skimmed  miik,  otherwise  it  contains  much 
of  the  butter  and  oily  part.  The  consis- 
tence of  curd  depends  on  a  number  of 
minute  circumstances,  being  sometimes 
quite  soft  and  gelatinous,  sometimes  firm 
and  as  it  were  knotty.  It  is  much  con- 
densed and  hardened  by  heat.  A  long 
continued  pressure  is  necessary,  in  order 
to  separate  entirely  the  adhering  portion 
of  whey.  Curd  (or  cheese)  from  skimmed 
milk,  when  slowly  dried  in  a  moderate 
heat,  becomes  hard,  brittle,  and  transpa- 
rent like  horn,  which  may  be  seen  in  some 
of  the  most  ordinary  cheeses  as  prepared 
for  food.  Whilst  it  retains  its  flexibility 
it  is  extremely  tough  and  tenacious,  and 
when  heated  it  draws  out  into  long  strings. 
If  the  heat  becomes  scorching  it  melts, 
takes  fire  and  burns  with  flame,  smoke, 
and  a  fetid  ammoniacal  smell. 

Curd  is  insoluble  in  water,  but  when 
long  kept  under  cold  water,  it  is  changed 
to  a  soft  fatty  matter,  considerably  diffe- 
rent from  the  original  substance. 

From  all  the  properties  of  pure  curd  it 
appears  to  bear  the  strongest  analogy  with 
the  white  of  egg,  as  Scheele  observes,  and 
it  may  be  considered  as  nearly  pure  albu- 
men, but  mixed  with  a  certain  portion  of 
phosphat  of  lime  and  a  few  other  saline 
Tiiatters.  Rouelle  compared  it  to  the  glu- 
ten of  wheat,  which  is  also  a  just  compa- 
rison, since  there  is  also  scarcely  any 
ascertainable  difference  between  pure 
gluten  and  pure  albumen  when  each  is 
m  a  condensed  coagulated  state  The 
effect  of  acids  upon  curd  will  be  presently 
noticed. 

Butter,  or  the  oily  part  of  milk,  is  well 
known  to  be  prepared  from  cream  by 
long  agitation.  New  milk  is  perfectly  ho- 
mogenous, but  on  standing  for  some  hours 


at  rest  it  throws  up  a  thick  yellowish, 
white  cream,  unctuous  to  the  touch,  and 
of  a  very  bland  agreeable  flavour.  In  the 
process  of  churning,  the  cream  separates 
visibly  into  two  substances,  the  butter 
which  collects  in  a  mass,  and  a  thick  white 
liquid,  the  buttermilk,  as  it  is  called,  and 
whey ;  and  still  retains  a  little  of  the  but- 
ter. 

Butter  is  much  more  easily  made  from 
stale  than  from  fresh  cream,  probably  ow- 
ing to  the  spontaneous  change  which 
cream  undergoes  by  keeping,  and  the 
evolution  of  an  acid.  Butter  often  varies 
in  colour,  being  of  every  shade  from  a 
faint  yellowish-white  to  a  deep  yellow, 
but  the  cause  of  this  variation  is  not  very 
apparent.  The  action  of  the  atmosphere 
has  been  thought  by  some  to  be  concern- 
ed in  the  separation  of  cream  from  milk, 
and  of  butter  from  cream  ;  but  nothing 
in  the  least  degree  satisfactory  has  been 
brought  in  support  of  this  opinion,  and  it 
is  certain  that  agitation  alone,  in  a  corked 
bottle,  will  perfectly  separate  butter  from 
cream. 

Fresh  butter  melts  at  about  98°,  and 
when  kept  for  some  time  melted,  a  small 
quantity  of  serum  and  curd  separate  from 
it.  The  butter  becomes  thereby  more 
transparent,  but  has  acquired  a  less  plea- 
sant taste.  Butter,  when  distilled  per  se, 
first  gives  over  some  water  holding  seba- 
cic  acid,  after  which  the  greater  part  of 
the  butter  rises  with  a  pungent  unplea- 
sant smell,  and  fixes  in  the  receiver  into 
a  concrete  empyreumatic  grease.  A  fur- 
ther distillation  of  this  grease  gives  a  finer 
and  more  volatile  oil  than  at  first,  and 
other  products  similar  to  those  of  the  ani- 
mal oils,  as  will  be  further  mentioned  un- 
der the  article  Oil.  Butter,  when  long 
kept,  becomes  excessively  fetid  and  ran- 
cid ;  but  this  is  in  a  great  measure  pre- 
vented by  salting.  Alkalies  dissolve  it 
with  ease  into  a  perfect  soap. 

On  the  whole,  butler  may  be  consider- 
ed as  most  resembling  the  animal  oils, 
but  intimately  combined  with  a  small  por- 
tion of  the  curd  and  whey,  and  other 
parts  of  the  milk,  from  which  probably  it 
can  never  be  separated  without  total  dis- 
organization ;  and,  indeed,  as  milk  is  a  na- 
tural emulsion  elaborated  in  the  vessels  of 
the  animal,  Ihe  combination  of  its  parts 
appears  throughout  to  be  so  close,  that  it 
is  scarcely  in  the  power  of  art  to  break  it 
entirely.  Hence  it  is  that  we  find  the 
whey  to  retain  almost  to  the  last  some  of 
the  curd  and  oil;  the  curd  to  be  almost 
inseparable  from  the  last  portions  of  the 
whey  and  butter  (to  which  much  of  the 
varieties  of  cheese  is  to  be  attributed)  and 


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wme  of  the  curd  and  whey  to  remain  in 
the  composition  of  butter  through  every 
process. 

All  acids  readily  curdle  milk ;  and,  as  ap- 
pears from  the  experiments  of  Scheele, 
confirmed  by  those  of  Messrs.  Fourcroy 
and  Vauquelin,  the  coagutum  thus  form- 
ed consists  of  the  curd  united  with  a  por- 
tion of  the  acid  employed,  insomuch  that, 
if  no  more  acid  be  used  than  is  barely  ne- 
cessary, the  whey  shews  no  marks  of  aci- 
dity. The  curd  obtained  by  mineral 
acids  (according  to  Scheele)  is  soluble  in 
an  excess  of  the  acid,  but  not  that  pro- 
duced by  vegetable  acids.  If  milk  be  pre- 
viously mixed  with  ten  parts  of  water,  no 
curd  is  obtained  by  mineral  acids ;  hence 
the  cause  of  coagulation  of  undiluted  milk 
in  this  case  is,  that  the  curd  and  acid  to- 
gether form  a  compound  which  requires 
for  its  solution  much  more  water  than  the 
milk  contains. 

When  milk  is  kept  in  a  warm  place,  it  is 
known  to  grow  sour  and  thick  in  about 
two  days,  according  to  the  temperature. 
This  sourness  daily  increases,  and  is  the 
strongest  when  about  a  fortnight  has 
elapsed,  and  it  then  consists  of  a  soft 
curd,  acid  and  somewhat  nauseous  to  the 
taste,  and  of  whey  highly  sour  and  whi- 
tish. A  strong  acid  is  therefore  generat- 
ed in  the  process,  which  was  first  accu- 
rately examined  by  Scheele,  who  disco- 
vered that  the  acid  differed  from  any 
other  then  known,  and  to  which  he  gave 
the  name  of  Lactic  Acid. 

Milk  is  susceptible  of  the  vinous  fer- 
mentation, so  as  to  be  made  to  yield  an 
ardent  spirit  by  subsequent  distillation  ; 
but  it  is  not  very  easy  to  ferment  milk, 
and  it  always  turns  sour  at  the  same  time. 
The  Tartars  and  other  Asiatic  nations 
have  been  from  time  immemorial  in  the 
habit  of  preparing  an  intoxicating  liquor 
from  mare's  milk.  This  is  called  kou- 
miss, and  the  process  is  thus  given  by  Dr. 
Grieve.  Take  any  quantity  of  mare's 
milk,  dilute  it  with  a  sixth  of  water,  pour 
it  into  a  wooden  vessel,  and  add  as  a  fer- 
ment about  one-eighth  of  very  sour  milk, 
or  better,  of  old  koumiss  ;  cover  the  ves- 
sel with  a  thick  cloth,  and  keep  it  in  a  mo- 
derate temperature.  After  standing  twen- 
ty-four hours,  a  thick  coagulum  rises  to 
the  top,  which  must  be  well  mixed  by 
beating.  After  reposing  for  another  day, 
it  is  again  stirred  till  it  becomes  quite  ho- 
mogeneous, and  in  this  state  it  forms  the 
koumiss,  which  has  an  agreeable  sweetish 
acescent  taste. 

Milk  in  the  state  of  koumiss  does  not 
easily  change  by  keeping.  By  distillation 
it  yields  a  considerable  quantity  of  alco- 
hol, as  much  (according  to  Pallas)  as  one- 
VOL.  II. 


third  of  its  bulk.  The  entire  milk  ap- 
pears essential  to  the  production  of  ar- 
dent spirit,  as  well  as  frequent  agitation 
to  mix  the  constituent  parts  which  the 
acid  has  caused  to  separate. 

Though  the  milk  of  different  animals  is 
found  to  be  essentially  the  same  in  the 
number  and  chemical  nature  of  the  seve- 
ral ingredients  (as  far  as  has  been  exa- 
mined) yet  a  very  considerable  difference 
is  found  in  the  proportion  of  these  sub- 
stances and  in  some  of  their  sensible  pro- 
perties. The  experiments  of  Parmentier 
are  particularly  curious  on  this  subject. 
The  kinds  of  m'ilk  that  he  examined  were, 
first,  cow's  milk,  as  a  standard,  to  which 
were  compared  the  following,  viz.  wo- 
man's, asses',  goat's,  ewe's,  and  mare's 
milk. 

Woman's  milk  is  sweeter  than  cow's, 
and  thinner  ;  but  it  is  of  all  others,  that 
which  varies  most  according  to  the  state 
of  body,  constitution,  age,  &c  of  the  per- 
son whence  it  is  drawn.  The  cream  is  on 
the  whole  more  copious  than  of  common 
cow's  milk,  but  it  differs  peculiarly  in 
this,  that  neither  agitation  nor  any  other 
known  means  will  entirely  separate  the 
butter ;  the  utmost  effect  of  these  means 
being  only  to  give  the  whole  cream  some- 
what of  an  unctuous  consistence,  without 
effecting  any  separation  into  butter,  curd, 
and  whey. 

Human  milk  also  deposits  part  of  its 
curd  by  mere  rest,  which  is  found  stick- 
ing to  the  sides  of  the  vessel  which  holds 
it.  Though  sweeter  to  the  taste  than 
cow's  milk,  it  does  not  contain,  sensibly, 
more  sugar. 

Asses'  milk  more  resembles  the  human 
than  any  other.  The  cream  is  in  small 
quantity,  by  agitation  it  gives  a  butter 
which  is  soft,  white,  and  nearly  tasteless. 
It  soon  becomes  very  rancid,  owing  pro- 
bably to  its  retaining  a  portion  of  the 
acid,  By  standing,  it  deposits  much  of 
the  curd,  even  before  it  becomes  sour. 

Goat's  milk  is  very  thick,  yellowish, 
and  pleasantly  flavoured.  It  is  somewhat 
denser  than  cow's  milk.  The  cream  is 
remarkably  thick  and  unctuous,  and  will 
keep  a  long  time  without  growing  sour 
or  sensibly  changing  By  agitation  it 
gives  a  very  firm,  solid,  and  white  butter, 
to  appearance  very  free  from  all  admix- 
ture. The  milk  also  abounds  in  curd,  so 
that,  when  heated,  a  much  thicker  pelli- 
cle rises,  and,  when  coagulated  by  any  of 
the  usual  methods,  the  curd  is  so  abun- 
dant, that  the  whey  is  with  difficulty  se- 
parable. It  is  also  of  a  very  gelatinous 
dense  consistence.  The  sugar  of  milk  is 
small  in  quantity,  but  separates  with 
ease. 


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Sheep*s  milk  resembles  cow's  very 
closely  in  taste  and  appearance.  It  yields 
abundance  of  cream,  which  by  churning 
affords  much  butter,  but  which  always  re- 
mains very  soft.  The  quantity  of  curd  is 
remarkably  large,  and  it  has  a  very  fat 
and  unctuous  appearance,  and  a  taste 
which  is  peculiar  to  it,  and  is  always  ve- 
ry distinguishable  in  ewe-milk  cheese. 

Mare's  milk  is  thin  and  insipid,  and 
does  not  coagulate  with  vinegar.  It  is 
remarkable  for  the  small  quantity  of 
cream  which  it  gives,  and  the  extreme 
difficulty  of  separating  the  butter  from  it 
by  agitation.  The  whey  contains  sulphat 
of  lime,  which  has  not  been  found  in  any 
other  milk. 

The  above-mentioned  species  of  milk 
all  resemble  each  other  essentially  in  the 
number  and  general  chemical  nature  of 
the  ingredients,  but  great  diversity  ap- 
pears in  their  respective  proportion,  and 
apparently  in  the  mode  of  mixture.  Thus 
with  regard  to  the  cream,  cow's  and 
sheep's  milk  yield  it  easily  by  repose,  its 
consistence  is  greater  than  in  the  others, 
and  the  butter  separates  more  perfectly. 
There  is  an  equal  difference  in  the  con- 
sistence of  the  curd,  that  from  cow's  and 
sheep's  milk  being  dense,  and  readily  se- 
parating by  the  usual  coagulating  sub- 
stances, but  the  curd  from  ass's  and 
mare's  milk  always  remains  thin,  and  al- 
most of  a  creamy  consistence. 

In  relation  to  the  subject  of  milk,  we 
shall  here  introduce  some  remarks  on 
churns,  with  one  or  two  drawings. 

Mr.  William  Bowler's  improved  churn, 
is  of  the  barrel  kind,  being  a  cylinder,  18 
inches  in  diameter,  and  9  wide ;  the  sides 
are  of  wood,  the  rim  a  tin  plate,  which 
has  two  openings ;  one  8^  inches  in 


length,  and  4  in  width,  through  which  the 
cream  is  poured  into  the  churn,  and  the 
hand  introduced  for  cleaning  it ;  the 
other,  a  short  pipe,  one  inch  in  diameter, 
by  which  the  butter-milk  runs  out  of  the 
churn,  when  the  operation  is  finished. 
The  first  of  these  openings  has  a  wrooden 
cover,  fastened  down  by  two  screws ;  and 
the  other  a  cork  fitted  to  it,  while  the  but- 
ter is  churning.  There  is  farther,  near 
the  larger  opening,  a  small  vent-hole, 
with  a  peg  to  admit  the  passage  of  any 
air  that  may  be  discharged  from  the 
cream,  at  the  beginning  of  the  operation. 
An  axle  also  passes  through  the  churn, 
terminating  in  two  gudgeons,  on  which  it 
hangs ;  its  lower  part  being  immersed  in 
a  trough,  in  order  to  hold  occasionally  ei- 
ther hot  or  cold  water,  according  to  the 
season  of  the  year.  On  the  inside  of  the 
rim,  are  four  projecting  pieces  of  wood, 
with  holes,  serving  to  agitate  the  cream 
by  the  motion  of  the  churn.  This  move- 
ment is  caused  by  a  pendulum  3  feet  6 
inches  long,  that  has  an  iron  bob,  weigh- 
ing 10  lbs.  and  at  its  upper  end  a  turning 
pulley,  10  inches  in  diameter,  from  which 
a  rope  goes  twice  round  another  pulley$ 
about  3  inches  in  diameter,  fixed  on  the 
axis  of  the  churn,  which  it  causes  to  make 
a  partial  revolution,  by  each  vibration  of 
the  pendulum. 

There  are  likewise  sliding  covers  to  the 
machinery,  and  also  another  to  the  water 
trough  ;  in  order,  when  hot  water  is  used, 
to  secure  the  steam,  and  keep  the  cream 
in  a  proper  degree  of  warmth.  The  mo- 
tion of  the  pendulum  is  given,  and  conti- 
nued, by  means  of  a  wooden  rod,  about 
3  feet  9  inches  in  length,  which  turns  on 
a  pin  3  inches  above  the  bob  of  the  pen 
dulum. 


BOWLER'S  IMPROVED  CHURN. 


MIL 


MIL 


Explanation  of  the  Cut  which  represents 
Mr.  William  Bov/ler's  improved  Churn. 

A.  A  The  body  of  the  churn,  of  tin. 

B.  An  opening  by  which  the  cream  is 
put  in. 

C.  The  cover  of  the  large  opening. 
The  small  hole  on  the  opposite  side  can- 
not be  delineated  in  the  print. 

D.  The  axis,  or  gudgeon,  on  which 
the  body  of  the  churn  is  suspended. 

E.  The  upper,  or  large  pulley. 

F.  The  smaller  pulley  fixed  on  the  axis 
of  the  churn. 

G.  The  rod  of  the  pendulum,  hanging 
from  the  upper  pulley  E. 

H.  The  bob  of  the  pendulum. 

I.  The  handle,  moveable  on  the  pin  at 
a,  by  which  the  pendulum  is  moved,  mak- 
ing a  traverse  in  the  form  of  the  dotted 
line  K.  K. 

L.  The  trough  for  the  hot  or  cold  water. 

To  be  made  of  tin,  because  a  better 
conductor  of  heat  than  wood. 

M.  A  projecting  piece  of  wood,  with 
a  shoulder,  which  supports  the  handle  I, 
when  the  churn  is  not  at  work. 

As  butter  is  often  made  in  small  quan- 
tities, and  the  vertical  motion  of  the  com- 
mon churn  is  extremely  fatiguing,  we 
consider  those  methods  of  applying  the 
powers  of  mechanism,  as  valuable  im- 
provements. Hence  we  presume  to  re- 
commend the  improved  butter-churns  to 
be  generally  introduced;  for  the  facility 
and  expedition  with  which  butter  is  thus 
obtained,  will  amply  compensate  the  ad- 
ditional expense. 

WRIGHT'S  CHURN. 


See  Mecha- 
nics. 


This  churn  is  made  in  the  form  of  a 
cube,  with  vertical  dashers,  as  a,  a,  a,  a, 
a,  a,  a,  a  ;  B,  the  top  that  takes  off;  C, 
the  handle  by  which  the  dashers  are 
turned ;  D,  D,  D,  the  form  of  the  churn 
each  way;  C,  the  spindle  that  goes 
through  the  dashers. 

MILK  PAINT.    See  Colour  Mak- 

ING. 

MILL. 

MILL-WORK. 

MILL  MACHINERY 

MILL-STONE.  The 'large  circular 
stone  used  in  mills,  for  the  purpose  of 
grinding  grain,  or  corn,  into  flour.  Mill- 
stones are  made  in  the  United  States,  but 
none  superior  to  those  manufactured  by 
Mr.  Oliver  Evans,  of  this  city.  The  bun- 
stone  is  found  in  Georgia,  and  in  the 
Western  Country.  The  acquisition  of 
this  stone,  may  be  considered  as  very  va- 
luable, from  its  extensive  utility  in  the 
manufacture  of  flour. 

These  stones  were  formerly  imported 
in  great  numbers  from  France  :  the  burr- 
stones  of  that  country  having  been  found 
harder  and  more  durable.  To  prevent 
the  expense,  the  Patriotic  Society  for  the 
Encouragement  of  Arts,  &c.  in  Britain, 
offered  a  liberal  premium  for  the  disco- 
very of  a  quarry  of  mill-stones  similar  to 
the  French  burrs ;  which  desirable  ob- 
ject was  attained  in  1799,  by  Mr.  Richard 
Bowes,  of  Conway,  in  North  Wales,  to 
whose  widow  the  Society,  in  1800,  voted 
the  reward  of  1001. 

In  the  year  1796,  a  patent  was  granted 
to  Mr.  Major  Pratt,  lor  his  invention  of  a 
method  of  manufacturing  a  composition- 
stone,  calculated  for  grinding  corn,  and 
various  other  articles,  in  the  same  man- 
ner as  is  effected  by  the  common  mill- 
stones. His  artificial  compound  is  stated 
to  consist  in  mixing  certain  proportions  of 
siliceous  and  argillaceous  earths  (that  can 
only  be  ascertained  by  practice,)  with 
about  one-seventh  part  of  calcareous  earth. 
These  are  exposed  to  a  fire,  heated  to  the 
degree  usually  required  in  calcining  lime, 
for  the  space  of  twenty -four  hours,  or  such 
farther  period  as  experience  alone  can  de- 
termine ;  after  which  the  composition  may 
be  formed  into  durable  stones.  The  Geor- 
gia burr,  however,  answers  every  pur- 
pose in  the  United  States. 

For  sundry  observations  on  mill-stones, 
see  Mechanics. 

MINERAL  WATERS.    See  Water, 

MINERALIZER.  See  Ore,  Metal- 
lurgy. 

MINES.    See  Metallurgy. 

MINIUM.    See  Lead. 

MIRROR. — A  mirror,  or  speculum,  is 
an  opaque  body,  whose  surface  is  very 


MOL 


MOS 


smooth  and  finely  polished,  so  that  it  will 
reflect  the  rays  of  light  which  fall  upon 
it,  and  by  ihis  means  represent  the  images 
of  objects  opposed  to  it 

Mirrors  are  generally  made  of  metal, 
or  glass  polished  on  one  side  and  silvered 
on  the  other,  and  are  either  plain,  convex, 
or  concave. 

Plain  mirrors,  are  those  whose  surfaces 
arc  perfect  planes,  and  whose  section  is  a 
straight  line;  such  are  vulgarly  called 
looking-glasses. 

Convex  mirrors,  are  those  whose  mid- 
die  parts  are  more  prominent  than  their 
extremities  or  edges  ;  and  whose  sections 
are  curves  which  may  be  either  circular, 
elliptical,  parabolical,  or  hyperbolical 

Concave-  mirrors,  are  those  whose  sur- 
faces sink  m  with  a  hollowness.  See 
Glass,  Speculum,  Silvering. 

MOHAIR,  mo ree. —The  Mohair  goats 
are  a  variety  of  the  common  goats,  being 
famous  for  their  soft  and  silver  white 
hairs,  the  like  of  which  are  not  to  be 
found  in  any  place  but  Angora.  This  hair 
is  commonly  carried  ready  spun  to  Eu- 
rope, and  being  there  woven  into  camlets 
and  other  manufactures,  particularly  by 
the  English,  is  afterwards  exported  to  all 
parts  of  the  world,  and  even  to  those 
whence  the  yarn  was  originally  brought. 

MOLASSES.    See  Melasses 

MOLYBDENA. — Molybdena  is  a  metal 
of  a  greyish  white  colour,  in  the  form  of 
brittle  infusible  grains.  It  is  convertible 
to  a  yellowish  white  oxyd  by  exposure  to 
the  air  at  a  red  heat,  or  by  the  action  of 
nitric  acid. 

Ores  of  Molybdena. 
Sp.  1.  Molybdena,  or  Sulphuret  of  Mo- 
lybdena. 

Sp.2.  Molybdat  of  Lead.  Yellow  Lead- 
spar. 

Reduction  of'  Ores. — Physical  properties  of 
Reguline  Molybdena. 
As  molybdena  is  a  metal  that  has  not 
hitherto  been  applied  to  any  use,  so  there 
has  been  no  attempt  in  the  great  way  to 
reduce  its  ores.  The  complete  decomposi- 
tion of  the  acid  or  oxyd  of  this  metal  has, 
however,  been  undertaken  by  various  che- 
mists, and  for  the  most  part  with  but  little 
success.  The  chief  cause  of  failure  seems 
to  have  been,  that  the  substance  operated 
on,  instead  of  being  the.  pure  metallic 
acid,  has  also  contained  a  portion  of  fixed 
alkali,  wThich,  by  its  affinity  for  the  acid, 
most  powerfully  opposes  its  deoxydation. 
The  method  that  as  yet  has  been  attended 
with  the  most  satisfactory  results,  is  that 
published  by  Helm.  The  acid  being  made 
into  a  paste  with  linseed  oil,  is  to  be  ex- 


posed to  a  strong  heat  in  a  covered  cru- 
cible; being  then  withdrawn  from  the  fire, 
the  black  mass  is  to  be  pulverized,  and 
again  mixed  with  oil,  and  torrefied  as  be- 
fore ;  by  repeating  this  two  or  three  times, 
the  molybdena  is  completely  reduced,  and 
assumes  its  proper  metallic  lustre.  It  ap- 
pears highly  probable,  that  the  method 
which  has  been  successfully  practised  in 
the  reduction  of  tunstic  acid,  would  be 
equally  efficacious  with  the  molybdic  acid. 
It  is  the  following.  Let  the  pure  molybdic 
acid  be  combined  with  as  much  ammonia 
cls  possible,  and  then  exposed  to  an  in- 
tense heat,  in  a  crucible  lined  with  char- 
coal :  the  ammonia  would  be  decomposed, 
and  its  hydrogeneous  base,  together  with 
the  charcoal,  would  probably  carry  off 
the  whole  of  the  oxygen  from  the  metal. 

Molybdena,  in  the  only  state  in  which 
it  has  hitherto  been  procured,  is  a  very 
loosely  adhering  aggregate  of  minute 
grains  of  a  yellowish  white  colour  and 
metallic  lustre.  When  recently  broken  it 
exhibits  a  greyish  white  colour.  It  is 
hard,  verv  brittle,  and  difficultly  fusible. 
Sp.  gr.  7.5. 

Molybdena,  or  sulphuret  of  molyb- 
dena, has  been  discovered  in  this  state, 
Chester  county,  but  the  metal  is  not  used 
in  the  arts. 

MORDANT.    See  Dyeing. 

MOROCCO  LEATHER.  See  Lea- 
ther. 

MORTAR.    See  Cement. 

MOSAIC  GOLD.    See  Copper. 

MOSAIC  WORK. — Under  the  name  of 
mosaic-work  are  included  such  perform- 
ances as  relate  to  inlaid  work;  as  tabla- 
tures  of  stone,  wood,  metals,  &c.  What 
we  are  now  treating  upon  is  that  which 
represents  not  only  all  manner  of  figures, 
in  their  proper  colours,  attitudes  and 
shapes,  as  large  as  those  that  are  lasting 
ornaments  in  churches,  and  other  public 
edifices,  but  also  in  small,  and  fit  to  grace 
the  cabinets  of  the  great  and  curious,  and 
imitate  a  picture  painted  in  miniature. 

The  antients,  who  practised  this  art 
with  much  skill  and  exactness,  have  left 
a  variety  of  their  performances,  which  are 
found  not  only  in  Italy,  Spain,  See.  but  also 
in  England.  Those  remaining  at  Rome 
are  the  finest,  in  the  temple  of  Bacchus, 
now  the  church  of  St.  Agnes ;  and  there 
are  also  curious  pieces  to  be  seen  at  Ve- 
nice, Pisa,  Florence,  and  other  places. 

The  modern  artists  have  improved  very 
much  in  this  performance,  and  whatever 
traveller  has  been  at  St.  Peter's  and  the 
palace  of  Borghese  at  Rome,  St.  Mark's 
at  Venice,  and  the  church  of  St.  Felicia  at 
Florence,  will  confess  they  have  seen 
wonders. 


MOU 


MOU 


Such  figures  are  composed,  jointed  and 
cemented  together  of  various  coloured 
stones  ;  but  since  nature  has  scarcely,  at 
least  not  sufficiently,  supplied  the  proper 
shades  requisite  for  a  masterly  perform- 
ance, that  defect  has  been  made  up  by 
counterfeiting  those  colours,  by  art,  in 
glass;  which  is  done  in  the  following 
manner : 

The  glass  materials  are  put  in  the  cru- 
cibles or  melting  pots,  and  being  in  fu- 
sion, such  a  colour  is  added  as  would 
make  the  shades,  in  the  manner  directed, 
in  the  art  of  making  artificial  gems ;  be- 
ginning with  the  lightest.  See  Glass. 
Having  mixed  it  well,  and  taken  out  the 
quantity  you  think  proper  with  an  iron 
ladle,  put  it  on  a  smooth  marble,  flatting 
it  with  another  to  a  proper  thickness; 
then  cut  it  quickly  into  small  pieces,  lay- 
ing them,  when  cold,  in  a  box  for  use : 
add  more  colour,  and  proceed  as  before, 
repeating  it  till  you  come  to  the  deepest 
shade.  If  you  would  gild  them,  wet  them 
on  one  side  with  gum-water,  and  lay  leaf 
gold  upon  them;  and  in  an  iron  shovel, 
covered  with  pieces  of  other  glass,  heat 
them  red  hot  in  the  mouth  of  a  furnace ; 
then  take  them  out,  and  when  cold,  the 
gold  will  be  so  fixed  and  firm  that  nothing 
can  hurt  it. 

When  you  begin  to  work,  lay  a  thick 
ground  against  the  cieling  or  wall,  with 
plaster,  and  having  your  design  ready 
drawn  and  painted  on  blue  or  brown 
paper,  clap  part  of  it  upon  the  wet  plas- 
ter, and  with  a  pair  of  small  pliers,  take 
up  the  small  stones,  and  press  them  in 
their  proper  places ;  forming  the  figures 
and  shades  in  their  respective  colours,  as 
you  are  directed  by  your  painted  model. 
In  this  manner  is  done  the  history  of"  Our 
Saviour's  walking  with  Peter  on  the  sea" 
in  St.  Peter's  church  at  Rome- 
Stones  cut  in  squares,  and  of  different 
colours,  imbedded  in  cement,  and  ar- 
ranged according  to  fancy,  form  the  Mo- 
saic pavements  of  ancient  temples,  mau- 
soleums &c,  specimens  of  which,  may  be 
seen  in  Peale's  museum. 

MOSS.    See  Archil,  Litmus. 
MOTHER  WATER.   See  Salt,  &c. 
MOULD.    See  Agriculture. 
MOULDS,  to  make,  for  Paper-frames, 
and  other  things,  as  fine  as  if  fresh  carved. 
Imison. 

Take  shavings  of  paper,  and  soak  them 
in  clean  water  for  the  space  of  six  or  eight 
days ;  then  boil  them  for  about  two  hours 
in  clean  water ;  this  done,  take  them  out 
of  the  pot,  with  as  little  moisture  as  pos- 
sible, and  stamp  them  in  a  stone  mortar, 
to  a  paste.  When  it  is  fine  enough,  let  it 
settle ;  pour  off  the  water  if  any  remains, 


and  put  the  stamped  paper  into  a  linen 
bag,  tied  close  :  hang  it  in  fair  water,  and 
keep  it  there  till  you  have  occasion  to 
make  use  of  it,  shifting  ihe  water  once  a 
week,  and  it  will  keep  good  for  twelve 
months  together.  When  your  mould  is 
ready,  you  may  at  any  time  take  off  the 
said  stamped  paper,  wringing  out  the 
water,  and,  tempering  it  with  a  little  size, 
of  what  colour  you  please  ;  put  it  on  the 
mould,  and  with  a  spunge  press  it  down, 
and  soak  up  the  superfluous  moisture 
from  it.  Having  thus  filled  the  mould,  set 
it  in  the  sun,  or  a  warm  room,  and,  when 
dry,  it  will  easily  come  off  the  mould,  and 
be"  like  plaster  of  Paris,  of  a  beautiful 
white.  You  may  afterwards  paint  or  gild  its 
or  make  any  use  of  it  you  intended.  It  will 
make  frames  to  pictures  ;  likewise  paper- 
hangings,  snuff-boxes,  and  many  other 
things."  You  may  cover  them  with  a  clear 
hard  varnish. 

MOULDING  AND  CASTING. — The 
art  of  taking  casts  or  impressions  from 
pieces  of  sculpture,  medals,  &c.  is  of  very 
great  importance  in  the  fine  arts.  Many 
excellent  impressions  have  been  made  in 
this  country  by  some  of  our  own  artists, 
equal  in  every  respect  to  the  foreign. 
Witness  the  elegant  bust  of  the  late  pro- 
fessor Rush,  the  mould  of  which  was  made 
by  Mr.  William  Rush,  the  carver. 

In  order  to  procure  a  copy  or  cast  from 
any  figure,  bust,  medal,  &c.  it  is  neces- 
sary to  obtain  a  mould,  by  pressing  upon 
the  thing  to  be  moulded  or  copied  some 
substance  which,  when  soft,  is  capable  of 
being  forced  into  all  the  cavities  or  hol- 
lows of  the  sculpture.  When  this  mould 
is  dry  and  hard,  some  substance  is  poured 
into  it,  which  will  fill  all  the  cavities  of 
the  mould,  and  represent  the  form  of  the 
original  from  which  the  mould  was  taken 

The  particular  manner  of  moulding  de- 
pends upon  the  form  of  the  subject  to  be 
worked  upon.  When  there  are  no  pro- 
jecting parts,  but  such  as  form  a  right  or 
a  greater  angle  with  the  principal  surface 
of  the  body,  nothing  more  is  required  than 
to  cover  it  over  with  the  substance  of 
which  the  mould  is  to  be  formed,  taking 
care  to  press  it  well  into  all  the  cavities  of 
the  original,  and  to  take  it  off  clean,  and 
without  bending. 

The  substances  used  for  moulding  are 
various,  according  to  the  nature  and  si- 
tuation of  the  sculpture.  If  it  may  be  laid 
horizontally,  and  will  bear  to  be  oiled  with- 
out injury,  plaster  of  Paris  may  be  advan- 
tageously employed,  which  may  be  poured 
over  it  to  a  convenient  thickness,  after 
oiling  it,  to  prevent  the  plaster  from  stick- 
ing. A  composition  of  bees-wax,  resin, 
and  pitch,  may  also  be  used,  which  will 


MOU 


MOU 


be  a  very  desirable  mould,  if  many  casts 
are  to  be  taken  from  it.  But  if  the  situa- 
tion of  the  sculpture  be  perpendicular,  so 
that  nothing  can  be  poured  upon  it,  then 
clay,  or  some  similar  substance,  must  be 
used.  The  best  kind  of  clay  for  this  pur- 
pose is  that  used  by  the  sculptors  for 
making  their  models  with;  it  must  be 
Worked  to  a  due  consistence,  and  having 
spread  it  out  to  a  size  sufficient  to  cover 
all  the  surface,  it  must  be  sprinkled  over 
with  whiting,  to  prevent  it  from  adhering 
to  the  original  Bees-wax  and  dough,  or 
the  crumb  of  new  bread,  may  also  be  used 
for  moulding  some  small  subjects. 

When  there  are  undercuttings  in  the 
bas-relief,  they  must  be  first  filled  up  be- 
fore it  can  be  moulded,  otherwise  the 
mould  could  not  be  got  off.  When  the 
casts  are  taken  afterwards,  these  places 
must  be  worked  out  with  a  proper  tool. 

When  the  model,  or  original  subject,  is 
of  a  round  form,  or  projects  so  much  that 
it  cannot  be  moulded  in  this  manner,  the 
mould  must  be  divided  into  several  parts, 
and  it  is  frequently  necessary  to  cast  seve- 
ral parts  separately,  and  afterwards  to  join 
them  together.  In  this  case,  the  plaster 
must  be  tempered  with  water  to  such  a 
consistence,  that  it  may  be  worked  like 
soft  paste,  and  must  be  laid  on  with  some 
convenient  instrument,  compressing  it  so 
as  to  make  it  adapt  itself  to  all  parts  of 
the  surface.  When  the  model  is  so  co- 
vered to  a  convenient  thickness,  the  whole 
must  be  left  at  rest  till  the  plaster  is  set 
and  firm,  so  as  to  bear  dividing  without 
falling  to  pieces,  or  being  liable  to  be  put 
out  of  its  form  by  any  slight  violence;  and 
it  must  then  be  divided  into  pieces,  in  or- 
der to  its  being  taken  o.F  from  the  model, 
by  cutting  it  with  a  knife  with  a  very  thin 
blade ;  and  being  divided,  must  be  cau- 
tiously taken  off,  and  kept  till  dry  :  but  it 
must  be  observed,  before  the  separation 
of  the  parts  be  made,  to  notch  them  across 
the  joints,  or  lines  of  division,  at  proper 
distances,  that  they  may  with  ease  and 
certainty  be  properly  put  together  again. 
The  art  of  properly  dividing  the  moulds, 
in  order  to  make  them  separate  from  the 
model,  requires  more  dexterity  and  skill 
than  any  other  thing  in  the  art  of  casting, 
and  does  not  admit  of  rules  for  the  most 
advantageous  conduct  of  it  in  every  case. 
Where  the  subject  is  of  a  round  or  sphe- 
roidal form,  it  is  best  to  divide  the  mould 
into  three  parts,  which  will  then  easily 
come  off  from  the  model;  and  the  same 
will  hold  good  of  a  cylinder,  or  any  regu- 
lar curve  figure. 

The  mould  being  thus  formed,  and  dry, 
and  the  parts  put  together,  it  must  be 


first  oiled,  and  placed  in  such  a  position, 
that  the  hollow  may  lie  upwards,  and  then 
filled  with  plaster  mixed  with  water ;  and 
when  the  cast  is  perfectly  set  and  dry,  it 
must  be  taken  out  of  the  mould,  and  re- 
paired when  necessary,  which  finishes  the 
operation. 

In  larger  masses,  where  there  would 
otherwise  be  a  great  thickness  of  the 
plaster,  a  core  may  be  put  within  the 
mould,  in  order  to  produce  a  hollow  in 
the  cast,  which  both  saves  the  expense  of 
the  plaster,  and  renders  the  cast  lighter. 

In  the  same  manner,  figures,  busts,  8cc 
may  be  cast  of  lead,  or  any  other  metal  in 
the  moulds  of  plaster  or  clay  ;  taking  care, 
however,  that  the  moulds  be  perfectly 
dry  ;  for,  should  there  be  any  moisture, 
the  sudden  heat  of  the  metal  would  con- 
vert it  into  vapour,  which  would  produce 
an  explosion  by  its  expansion,  and  blow 
the  melted  metal  about. 

On  the  subject  of  statuary,  as  connect- 
ed with  this  subject,  we  shall  offer  the 
following  observations  : 

When  a  statue  is  to  be  formed  of  stone, 
marble,  8cc.  a  drawing  is  first  made  of  the 
subject  intended  to  be  carved ;  a  model  is 
next  made,  by  laying  a  mass  of  moist  clay 
on  a  board,  and  reducing  it  to  shape  and 
form  with  knives  and  spattles.  Some- 
times a  model  is  made  without  any  pre- 
vious drawing,  and  sometimes  the' stone 
is  cut  from  a  drawing  without  a  model. 

The  marble  or  stone  is  carved  with 
steel  chisels  of  different  sizes,  and  a 
wooden  maul.  The  statue  is  not  made  in 
a  single  piece,  but  of  several ;  which,  when 
finished,  are  fastened  together,  with  a  ce- 
ment f  the  powder  of  calcined  alabaster, 
called  plaster  of  Paris  ;  this  is  mixed  with 
water  to  the  thickness  of  batter,  which  in 
a  short  time  becomes  as  hard  as  the  mar- 
ble iiself,  and  is  as  durable. 

The  Parian  marble  is  the  most  cele- 
brated; and  from  this,  which  is  of  a  most 
beautiful  white,  the  greatest  part  of  the 
Grecian  statues  were  made.  It  is  also 
called  statuary  marble,  and  is  generally 
supposed  to  have  had  its  name  from  the 
island  Paros,  one  of  the  Cyclades  in  the 
iEgean  sea,  where  it  was  found ;  by  others 
the  name  is  derived  from  Agoracritus  Pa- 
rius,  a  famous  statuary,  who  gave  it  cele- 
brity by  cutting  a  statue  of  Venus  from  it. 
See  Marble. 

Among  the  many  statues  of  antiquity 
cut  out  of  this  marble,  is  that  of  Lao- 
coon  and  his  two  sons,  which  is  mention- 
ed by  Pliny,  and  has  escaped  the  injuries 
of  time. 

Almost  all  white  marbles  now  go  under 
the  name  of  Parian  marble ;  and  among 


MOU 

die  workmen  they  have  the  common  name 
of  alabasters,  though  they  come  from  dif- 
ferent places,  as  from  Spain,  some  parts 
of  France,  Italy,  &c.  Marble  is  also  found 
in  this  country. 

Dxdalus  has  been  celebrated  as  the  in- 
ventor of  statues,  but  it  is  certain  that 
there  were  statuaries  before  his  time.  He 
was,  however,  the  first  person  that  found 
the  method  of  making-  them  appear  as  if 
they  were  alive.  Till  his  time  statues 
were  made  with  their  feet  joined  together : 
he  loosened  their  feet,  and  gave  them  the 
attitudes  of  people  walking  and  acting. 

Statues  are  usually  distinguished  into 
four  general  kinds.  The  first  are  those 
less  than  life,  of  which  kind  are  the  sta- 
tues of  great  men,  of  kings,  and  of  the 
gods  themselves.  The  second  are  those 
equal  to  the  life ;  with  these  the  ancients 
celebrated  the  deeds  of  men  eminent  for 
learning  or  valour.  The  third  are  those 
that  exceed  life;  among  which  some  sur- 
passed the  life  once  and  a  half :  these 
were  for  monarchs  and  emperors,  and 
those  double  the  life  for  heroes.  The 
fourth  kind  were  still  larger :  these  were 
called  colossuses,  or  colossal  statues.  Of 
this  last,  the  most  eminent  was  the  colos- 
sus of  Rhodes,  one  of  the  wonders  of  the 
world,  a  brazen  statue  of  Apollo,  so  high, 
that  ships  passed  in  full  sail  between  its 
legs.  It  was  the  workmanship  of  Chares, 
who  spent  twelve  years  in  making  it. 

To  take  a  Cast  in  Metal,  from  any  small 
Animal,  Insect,  or  Vegetable. 

Prepare  a  box  of  four  boards,  suffi- 
ciently large  to  hold  the  animal,  in  which 
it  must  be  suspended  by  a  string,  and  the 
legs,  wings,  &c.  of  the  animal,  or  the  ten- 
drils, leaves,  &c.  of  the  vegetable,  must 
be  separated,  and  adjusted  in  their  right 
position  by  a  pair  of  small  pincers.  A  due 
quantity  of  plaster  of  Paris  mixed  with 
talc,  must  be  tempered  to  the  proper  con- 
sistence with  water,  and  the  sides  of  the 
box  oiled.  Also  a  straight  piece  of  stick 
must  be  put  to  the  principal  part  of  the 
body,  and.  pieces  of  wire  to  the  extremi- 
ties of  the  other  parts,  in  order  that  they 
may  form,  when  drawn  out  after  the  mat- 
ter of  the  mould  is  set  and  firm,  proper 
channels  for  pouring  in  the  metal,  and 
vents  for  the  air,  which  otherwise,  by  the 
rarefaction  it  would  undergo  from  the 
heat  of  the  metals,  would  blow  it  out,  or 
burst  the  mould.  In  a  short  time  the 
plaster  will  set,  and  become  hard,  when 
the  stick  and  wires  may  be  drawn  out,  and 
the  frame  or  coffin  in  which  the  mould 
was  cast  taken  away  i  and  the  mould  must 
then  be  put,  first,  into  a  moderate  heat, 


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and,  afterwards,  when  it  is  as  dry  as  can 
be  rendered  by  that  degree,  removed  into 
a  greater,  which  may  be  gradually  in- 
creased, till  the  whole  be  red  hot.  The 
animal  or  vegetable  inclosed  in  the  mould, 
will  then  be  burnt  to  a  coal ;  and  may  be 
totally  calcined  to  ashes,  by  blowing  for 
some  time  into  the  charcoal  and  passages 
made  for  pouring  in  the  metal,  and  giving 
vent  to  the  air,  which  will,  at  the  same 
time  that  it  destroys  the  remainder  of  the 
animal  or  vegetable  matter,  blow  out  the 
ashes.  The  mould  must  then  be  suffered 
to  cool  gently,  and  will  be  perfect,  the  de- 
struction of  the  substance  included  in  it, 
having  producing  a  corresponding  hollow ; 
but  it  may  nevertheless  be  proper  to  shake 
the  mould,  and  turn  it  upside  down,  as 
also  to  blow  with  the  bellows  into  each  of 
the  air  vents,  in  order  to  free  it  wholly 
from  any  remainder  of  the  ashes ;  or  where 
there  may  be  an  opportunity  of  filling  the 
hollow  with  quicksilver,  it  will  be  found  a 
very  effectual  method  of  clearing  the  ca- 
vity, as  all  dust,  ashes,  or  small  detached 
bodies,  will  necessarily  rise  to  the  surface 
of  the  quicksilver,  and  be  poured  out  with 
it.  The  mould  being  thus  prepared,  it 
must  be  heated  very  hot,  when  used,  if 
the  cast  is  to  be  made  with  copper  or 
brass,  but  a  less  degree  will  serve  for 
lead  or  tin.  The  metal  being  poured  into 
the  mould,  must  be  gently  struck,  and 
then  suffered  to  rest  till  it  be  cold  ;  at 
which  time  it  must  be  carefully  taken 
from  the  cast,  but  without  force  ;  for  such 
parts  of  the  matter  as  appear  to  adhere 
more  strongly,  must  be  softened  by  soak- 
ing in  water  till  they  be  entirely  loosened, 
that  none  of  the  more  delicate  parts  of  the 
cast  may  be  broken  off*  or  bent. 

When  talc  cannot  be  obtained,  plaster 
alone  may  be  used  ;  but  it  is  apt  to  be 
calcined  by  the  heat  used  in  burning  the 
animal  or  vegetable  from  whence  the  cast 
is  taken,  and  to  become  of  too  incoherent 
and  friable  a  texture.  Stourbridge,  or 
any  other  good  clay,  washed  perfectly 
fine,  and  mixed  with  an  equal  part  of  fine 
sand,  may  be  employed.  Pounded  pum- 
ice-stone, and  plaster  of  Paris,  in  equal 
quantities,  mixed  with  washed  clay  in  the 
same  proportion,  is  said  to  make  excel- 
lent moulds. 

Method  of  taking  a  Cast  in  Plaster  from  a 
person"  s  face. 
The  person  whose  likeness  is  required 
in  plaster,  must  lie  on  his  back,  and  the 
hair  must  be  tied  back,  so  that  none  of  it 
covers  the  face.  Into  each  nostril  convey 
a  conical  piece  of  stiff  paper  open  at  both 
ends,  to  allow  of  breathing.  The  face  is 
then  lightly  oiled  over  in  every  part  with 


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salad  oil,  to  prevent  the  plaster  from  stick- 
ing to  the  skin.  Procure  some  fresh-burnt 
plaster,  and  mix  it  with  water  to  a  proper 
consistence  for  pouring.  Then  pour  it  by 
spoonfuls  quickly  all  over  the  face  (taking- 
care  the  eyes  are  shut),  till  it  is  entirely 
covered  to  the  thickness  of  a  quarter  of 
an  inch.  This  substance  will  grow  sen- 
sibly hot,  and  in  a  few  minutes  will  be 
hard.  This  being  taken  off,  will  form  a 
mould,  in  which  a  head  of  clay  may  be 
moulded,  and  therein  the  eyes  may  be 
opened,  and  such  other  additions  and  cor- 
rections may  be  made  as  are  necessary. 
Then,  this  second  face  being  anointed 
with  oil,  a  second  mould  of  plaster  must 
be  made  upon  it,  consisting  of  two  parts 
joined  lengthwise  along  the  ridge  of  the 
nose  ;  and  in  this  a  cast  in  plaster  may  be 
taken,  which  will  be  exactly  like  the  ori- 
ginal. 

To  take  Casts  from  Medals. 

In  order  to  take  copies  of  medals,  a 
mould  must  first  be  made ;  this  is  gene- 
rally either  of  plaster  of  Paris,  or  of 
melted  sulphur. 

After  having  oiled  the  surface  of  the 
medal  with  a  little  cotton,  or  a  camel's- 
hair  pencil  dipped  in  oil  of  olives,  put  a 
hoop  of  paper  round  it,  standing  up  above 
the  surface  of  the  thickness  you  wish  the 
mould  to  be.  Then  take  some  plaster  of 
Paris,  mix  it  with  water  to  the  consist- 
ence of  cream,  and  with  a  brush  rub  it 
over  the  surface  of  the  medal,  to  prevent 
air-holes  from  appearing;  then  immediate- 
ly afterwards  make  it  to  a  sufficient  thick- 
ness, by  pouring  on  more  plaster.  Let  it 
stand  about  half  an  hour,  and  it  will  in 
that  time  grow  so  hard,  that  you  may 
safely  take  it  off.:  then  pare  it  smooth  on 
the  back  and  round  the  edges  neatly.  It 
should  De  dried,  if  in  cold  or  damp  wea- 
ther, before  a  brisk  fire.  If  you  cover  the 
face  of  the  mould  with  fine  plaster,  a 
coarser  sort  will  do  for  the  back  ;  but  no 
more  plaster  should  be  mixed  up  at  one 
time  than  can  be  used,  as  it  will  soon  get 
hard,  and  cannot  be  softened  without 
burning  over  again. 

Sulphur  must  not  be  poured  upon  sil- 
ver medals,  as  this  will  tarnish  them. 

To  prepare  this  mould  for  casting  sul- 
phur or  plaster  of  Paris  in,  take  half  a 
pint  of  boiled  linseed-oil,  and  oil  of  tur- 
pentine one  ounce,  and  mix  them  together 
in  a  bottle ;  when  wanted,  pour  the  mix- 
ture into  a  plate  or  saucer,  and  dip  the 
surface  of  the  mould  into  it;  take  the 
mould  out  again,  and  when  it  has  sucked 
in  the  oil,  dip  it  again.  Repeat  this,  till 
the  oil  begins  to  stagnate  upon  it ;  then 
take  a  little  cotton  wool,  hard  rolled  up, 
to  prevent  the  oil  from  sticking  to  it,  and 


wipe  it  carefully  off.  Lay  it  in  a  dry  place 
for  a  day  or  two  (if  longer  the  better)  and 
the  mould  wiil  acquire  a  very  hard  sur- 
face from  the  effect  of  the  oil. 

To  cast  plaster  of  Paris  in  this  mould, 
proceed  with  it  in  the  same  manner  as 
above  directed  for  obtaining  the  mould 
itself,  First  oiling  the  mould  with  olive-oil. 
If  sulphur  casts  are  required,  !t  must  be 
melted  in  an  iron  ladle. 

Another  method  with  Isinglass. — Dis- 
solve isinglass  in  water  over  the  fire;  then 
with  a  hair-pencil,  lay  the  melted  isinglass 
over  the  medal;  and  when  you  have  co- 
vered it  properly,  let  it  dry.'  When  it  is 
hard,  raise  the  isinglass  up  with  the  point 
of  a  penknife,  and  it  will  fly  off  like  horn, 
having  a  sharp  impression  of  the  medal. 

The  isinglass  may  be.  made  of  any  co- 
lour, by  mixing  the  colour  with  it ;  or  you 
may  breathe  on  the  concave  side,  and  lay 
gold  leaf  on  it;  which,  by  shining  through, 
will  make  it  appear  like  a  gold  medal. 
But  if  you  wish  to  imitate  a  copper  me- 
dal, mix  a  little  carmine  with  the  isin- 
glass, and  lay  gold  leaf  on  as  before. 

To  colour  Plaster. 
Plaster  of  Paris  may  be  tinged  with  se- 
veral colours,  when  you  are  casting,  by 
mixing  with  it  Prussian  blue,  red  lead,  or 
yellow  ochre,  with  which  you  may  com- 
pose a  blue,  red,  yellow,  and  green.  As 
the  coloured  plaster  takes  a  little  more 
time  to  dry  than  when  it  is  unmixed,  you 
may  sift  some  dry  plaster  upon  the  back 
of  the  casts  when  in  the  mould,  which 
will  make  them  dry  quicker. 

To  make  Sulphur  red  or  green,  or  to  make 
it  resemble  Marble. 

Take  two  ounces  of  the  best  clean  stone 
brimstone,  and  melt  it  slowly  over  a  gen- 
tle fire,  without  letting  it  flame;  when  it 
is  melted,  add  one  ounce  of  vermilion ; 
stir  them  well  together  ;  then  pour  the 
composition  over  the  surface  of  your 
mould,  and  immediately  pour  it  off  again, 
and  fill  the  mould  up  to  a  proper  thick- 
ness with  common  brimstone :  let  it  stand 
the  same  time  as  before  mentioned,  then 
pare  it,  and  rub  over  the  surface  with 
some  clean  cotton,  which  will  give  it  a 
polish.  The  more  impressions  you  can 
make  at  one  melting  the  better,  because 
the  brightness  of  the  red  fades  the  oftener 
it  is  melted.  It  may^  be  made  green  by 
adding  the  same  quantity  of  the  best  smalt 
instead  of  vermilion  ;  only  it  requires  more 
stirring  to  mix  it  properly.  It  may  also 
be  made  to  imitate  a  beautiful  marble, 
thus :  Mix  with  it  several  colours  sepa- 
rately, and  make  them  into  small  squares 


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MUC 


of  equal  sixes ;  dispose  them  according  to 
your  fancy,  endwise,  in  an  iron  frame  that ! 
will  open  with  a  joint;  after  which  melt  j 
them  together,  and  the  colours  will  unite  ! 
in  a  pleasing-  manner,  and  each  will  ap- 
pear distinct.    When  you  melt  it,  he  care- 
ful not  to  shake  it,  and  let  it  cool  by  de- 
grees. 

Sulphur  may  also  be  made  to  have  a 
metallic  appearance,  by  rubbing-  it  over 
with  powder  of  black  lead. 

MOULDING  CARVING  IN  WOOD, 
the  Artof,  according  to  Lenormand,  Pro- 
fessor of  Natural  Philosophy  in  the  Central 
School  of  the  Department  of  Tarn — "I 
made  (says  he)  very  clear  glue  with  five 
parts  of  Flanders  glue,  and  one  part  of 
fish  glue  or  isinglass.  1  dissolved  these 
two  kinds  of  glue  separately  in  a  large 
quantity  of  water,  and  mixed  them  to- 
gether after  they  had  been  strained 
through  a  piece  of  fine  linen  to  separate 
the  filth  and  heterogeneous  parts  which 
could  not  be  dissolved.  The  quantity  of 
water  cannot  be  fixed,  because  all  kinds 
of  glue  are  not  homogeneous,  so  that  some 
require  more  and  some  less.  The  proper 
degree  of  liquidity  may  be  known  by  suf- 
fering- the  mixed  glue  to  become  perfect- 
ly cold  :  it  must  then  form  a  jelly,  or  ra- 
ther a  commencement  of  jelly.  If  it  hap- 
pens that  it  is  still  liquid  when  cold,  a 
little  of  the  water  must'  be  evaporated  by 
exposing  the  vessel  in  which  it  is  contain- 
ed to  heat.  On  the  other  hand,  if  it  has 
too  much  consistence,  a  little  warm  water 
must  be  added.  In  a  word,  the  proper 
degree  will  be  ascertained  by  a  few  trials. 

The  glue  thus  prepared,  is  to  be  heated 
till  you  can  scarcely  endure  your  finger  in 
it :  by  this  operation  a  little  water  is  eva- 
porated, and  the  glue  acquires  more  con- 
sistence. Then  take  fine  raspings  of  wood 
or  saw -dust,  sifted  through  a  fine  hair 
sieve,  and  form  it  into  a  paste,  which  must 
be  put  into  moulds  of  plaster  or  sulphur, 
after  they  have  been  well  rubbed  over  with 
linseed  or  nut-oil,  in  the  same  manner  as 
when  plaster  is  to  be  moulded.  Care 
must  be  taken  to  press  the  paste  in  the 
mould  with  your  hand,  in  order  that  it 
may  acquire  all  the  forms  of  the  mould: 
then  cover  it  with  an  oiled  board,  and, 
placing  over  it  a  weight,  suffer  it  in  that 
manner  to  dry.  The  desiccation  may  be 
hastened  and  rendered  more  complete  by 
a  stove.  When  the  impression  is  dry,  re- 
move the  rough  parts,  and  if  any  inequa- 
lities remain  behind  they  must  be  smooth- 
ed ;  after  which  the  impression  may  be  af- 
fixed with  glue  to  the  article  for  which  it 
is  intended.  Then  cover  it  with  a  few 
strata  of  spirit  of  wine  varnish,  as  is  done 

VOL.  II. 


in  general  in  regard  to  carved  work,  or 
!  with  wax  in  the  encaustic  manner.   It  re- 
i  quires  much  attention  to  discover  that 
!  such  ornaments  are  not  carved  in  the 
usual  manner.    Gilding  may  be  applied 
to  them  with  great  facility.    This  opera- 
tion is  exceedingly  easy  j  nothing  is  ne- 
cessary but  moulds;  and  with  a  little 
art  the  ornaments  may  be  infinitely  va- 
ried 

I  tried  also  to  mould  figures,  and  com- 
pletely succeeded.  These,  however,  re- 
quire more  care.  I  first  make  a  paste,  si- 
milar to  the  former,  with  very  fine  saw- 
dust, and  place  a  stratum,  of  about  two 
lines  in  thickness,  on  every  part  of  the 
mould ;  after  which  it  is  left  to  dry  al- 
most entirely.  In  the  mean  time  I  pre- 
pare a  coarse  paste,  with  coarse  sawdust, 
which  has  not  been  made  to  pass  through 
a  fine  but  a  coarse  sieve,  and  instead  of 
Flanders  glue  I  employ  common  glue, 
which  is  less  expensive,  adding  to  it  a 
sixth  of  fish  glue.  I  first  put  together  two 
parts  of  the  mould,  after  introducing  into 
the  joints  a  slight  stratum  of  the  fine 
paste,  which  I  make  very  clear,  and  ap- 
ply with  a  small  brush.  1  fill  up  the  va- 
cuity between  the  two  pieces  with  coarse 
paste.  I  then  apply  the  third  piece  as  I 
did  the  second,  and  so  on  until  the  whole 
are  adjusted,  always  filling  up  the  vacui- 
ties with  coarse  paste.  I  suffer  the  whole 
to  dry  in  the  mould,  and  obtain  a  figure 
in  relief  of  solid  wood,  executed  with  all 
the  delicacy  of  plaster  figures.  Care  must 
be  taken  to  remove  with  a  sharp  knife,  or 
a  small  file,  the  prominences  formed  by 
the  joinings.  If  the  figure  be  not  suffered 
to  dry  too  much,  these  prominences  may 
be  easily  removed  with  the  point  of  a 
sharp  penknife.  It  will  be  necessary  to 
learn  the  art  of  determining  the  proper 
degree  of  desiccation  ;  for  if  the  figure  be 
taken  from  the  mould  before  it  is  properly 
dried  it  will  become  warped,  and  if  it  be 
too  dry  it  cannot  be  corrected  but  with  a 
file,  which  is  tedious  and  laborious, 
whereas  it  the  proper  moment  be  seized 
the  paste  may  be  cut  like  wax;  especially 
if  the  sawdust  has  been  fine,  which  is  ne- 
cessary for  the  exterior  strata.  The 
figures  may  then  be  completely  dried  in 
a  stove,  by  which  means  they  will  acquire 
a  degree  of  desiccation  and  solidity  hard- 
ly to  be  conceived.  Figures  thus  moulded 
may  be  bronzed,  or  varnished  ;  they  will 
then  be  unalterable  by  the  effects  of  mois- 
ture or  dryness. 

I  have  already  said,  he  concludes,  that 
Flanders,  and  not  common  glue,  ought 
to  be  employed  for  the  exterior  strata, 
because  this  glue  is  almost  colourless; 
K 


MUC 


MUC 


whereas  the  other,  being  dark-coloured, 
gives  too  obscure  a  tint  even  to  walnut- 
tree  wood. 

MUCILAGE,  a  substance  valuable  in 
water,  whether  hot  or  cold,  with  which  it 
forms  a  transparent  adhesive  or  gluey 
mass.  Vegetable  substances  usually  re- 
ceive the  name  of  gum,  and  animal  sub- 
stances affords  a  substance  called  glue. 
See  Gelatin,  8tc 

The  purest  of  the  gum -mucilages  is 
Gum-Arabic  or  Senegal,  which  forms  a 
very  valuable  article  of  commerce  to  the 
countries  that  yield  it.  An  inferior  sort 
of  gum  for  the  purposes  of  manufacture, 
but  closely  resembling  gum-arabic  in 
every  property,  is  that  which  exudes  from 
cracks  in  plumb,  peach,  pear,  and  other 
fruit  trees,  and  has  generally  the  colour 
of  amber.  Besides  these  sources  of  gum- 
mucilage,  there  are  many  vegetables 
whose  native  juices  so  much  abound  with 
mucilage,  that  a  considerably  pure  and 
solid  gum  may  be  obtained  by  simple  de- 
coction of  the  plant,  and  evaporation  to 
dryness.  Several  of  the  lichens,  the  leaves 
of  the  comfrey  and  mullen,  the  root  of  the 
hare -bell,  and  the  whole  plant  of  the 
marsh-mallow,  afford  a  good  mucilage  in 
this  method. 

We  shall  first  give  a  short  account  of 
the  gathering  of  the  gum-senegal,  before 
we  proceed  to  the  chemical  properties  of 
mucilage.  The  gum-arabic  is  obtained  in 
a  similar  manner,  and  Cairo  and  Alexan- 
dria were  the  principal  marts  for  this  gum, 
till  the  Dutch  introduced  the  gum  from 
Senegal  into  Europe,  about  the  beginning 
of  the  seventeenth  century,  and  which  now 
supplies  the  greater  part  of  the  vast  con- 
sumption  of  this  article. 

The  tree  which  yields  this  gum  is  a 
species  of  mimosa,  which  grow  abundant- 
ly on  the  sands  along  the  whole  of  the 
Barbary  coast,  and  particularly  about  the 
river  Senegal.  There  are  several  species, 
some  of  which  yield  a  red  astringent 
juice,  which,  when  inspissated,  forms  the 
Catechu,  but  others  afford  only  a  pure 
nearly  colourless  insipid  gum,  which  is 
the  great  article  of  commerce.  These 
trees  are  from  18  to  20  feet  high,  whh 
thorny  branches.  The  gum  makes  its  ap- 
pearance about  the  middle  of  November, 
when  the  soil  has  been  thoroughly  satu- 
rated with  the  periodical  rains.  The  gum 
my  juice  is  seen  to  ooze  through  the 
trunk  and  branches,  and  in  about  a  fort- 
night it  hardens  into  roundish  drops  <>f  a 
yellowish-white,  which  are  beautifully 
brilliant  where  they  are  broken  ofFj  and 
entirely  so  when  held  in  the  mouth  for  a 
short  time  to  dissolve  the  outer  surface. 


No  clefts  are  made,  nor  any  artificial 
means  used  by  the  Moors  to  solicit  the 
flow  of  the  gum.  The  lumps  of  gum-se- 
negal are  usually  about  the  side  of  par- 
tridge eggs,  and  the  harvest  continues 
about  six  weeks.  The  quantity  annually 
sold  out  of  the  Senegal  country  for  Euro- 
pean consumption,  is  about  twelve  hun- 
dred thousand  pounds  weight. 

This  gum  is  also  a  very  wholesome  and 
nutritious  food,  thousands  of  the  Moors 
supporting  themselves  entirely  upon  it  du- 
ring the  time  of  harvest.  About  six  ounces 
is  sufficient  to  support  a  man  for  a  day, 
and  it  is  besides  mixed  with  milk,  animal 
broths,  and  other  victuals. 

The  gum-arabic,  or  that  which  comes 
directly  from  Egypt  and  the  Levant,  only 
differs  from  the  gum-senegal  in  being  of  a 
lighter  colour  and  in  smaller  lumps,  and 
it  is  also  somewhat  more  brittle.  In  all 
other  respects  the  two  resemble  each 
other  perfectly.  Its  specific  gravity  is 
about  1.45. 

The  uses  of  this  gum  are  very  great 
and  numerous.  The  greatest  consump- 
tion of  gum-senegal  is  in  furnishing  a 
thick  viscid  fluid,  with  which  the  differ- 
ent mordants  are  mixed  in  calico-print 
ing,  which  has  been  more  particularly  de- 
scribed in  the  article  Dyeing. 

Another  great  use  of  gum-arabic  is  in 
giving  a  fine  gloss  or  glazing  to  ribbons 
and  silks  For  this  purpose  a  thin  solu- 
tion is  made,  and  the  silk  slightly  brush- 
ed over  with  it,  and  when  dry  it  leaves  a 
very  thin  colourless  varnish,  but  readily 
washed  off  by  water,  whence  the  spotted 
appearance  that  a  shower  of  rain  gives  to 
these  articles.  Gum-arabic  is  also  used 
as  a  clean,  convenient,  and  pretty  strong 
cement  for  an  infinite  number  of  purposes 
where  there  is  no  risk  of  moisture.  Its 
ready  solubility  in  water,  and  the  length 
of  time  which  the  solution  will  keep  with- 
out spoiling,  render  it  highly  valuable  in 
the  arts 

This  gum  is  also  employed  in  pharma- 
cy, as  a  very  convenient  way  of  rendering 
miscibie  with  water,  oils,  resins,  and  other 
substances,  on  which  water  alone  has  no 
action.  The  effect  here  is  chiefly  mecha- 
nical. The  substance  (olive  oil  for  exam- 
ple) is  to  be  well  rubbed  with  about  half 
its  weight  of  a  strong  solution  of  gum, 
and  the  watery  liquid  afterwards  added 
by  degrees,  and  with  constant  rubbing ; 
and  by  this  method  an  opake  emulsion  is 
formed,  in  which  the  substances  will  re- 
main mixed  for  many  hours,  nor  will  they 
again  entirely  separate. 

To  obtain  the  gum-mucilage  from  those 
vegetables  that  do  not  yield  it  by  exsuda^ 


MUC 


MLR 


lion,  recourse  must  be  had  to  boiling  with 
water,  and  evaporation.  These  kinds  of 
mucilage,  however,  will  seldom  answer 
as  cements,  as  they  will  not  sufficiently 
harden  by  drying',  and  they  are  more  lia- 
ble to  mould,  and  to  become  brown  and 
coloured  during-  the  requisite  evapora- 
tion. 

Lord  Dundonald  has  given  the  follow- 
ing directions  for  preparing  the  mucilage 
from  the  lichen.  This  plant  is  the  com- 
mon large-leaved  moss,  that  grows  so 
abundantly  on  forest  and  fruit  trees,  and 
in  the  north  of  Europe  and  America,  it 
grows  to  the  length  of  a  foot  or  more, 
giving  a  nutritious  food  to  deer  and  other 
animals.  The  lichen  has  an  ouler  skin, 
and  below  this  a  green  resinous  substance, 
and  the  remainder  of  the  plant  consists 
chiefly  of  gum  and  of  fibrous  matter  on 
which  water  has  no  action.  To  separate 
the  outer  skin  and  the  resinous  matter, 
the  plant  must  be  scalded  two  or  three 
times  with  boiling  water,  whereby  the 
skin  cracks,  swells,  and  peels  oft'.  After 
this  it  is  to  be  put  into  a  boiler  with  about 
three  quarts  of  water  for  every  pound  of 
the  plant,  and  about  half  an  ounce  of  pot- 
ash or  soda  (which  assists  the  extraction) 
and  the  boiling  should  be  continued  till 
the  liquor  acquires  a  considerable  degree 
of  gummy  consistence.  The  liquor  is  then 
to  be  taken  out  and  strained  from  the 
plant,  and  fresh  water  added  to  the  same 
material,  further  to  exhaust  the  gum.  The 
several  liquors,  after  standing  some  hours 
to  settle,  and  then  removing  the  dregs, 
are  to  be  boiled  down  in  a  regulated  heat 
to  the  consistence  which  is  required  for 
us>e,  but  not  further,  lest  it  should  burn 
and  become  coloured.  It  requires  two  or 
even  three  boilings  entirely  to  exhaust  the 
lichen  of  its  mucilage. 

The  method  to  be  pursued  in  extract- 
ing the  mucilage  from  other  plants  is  so 
similar,  that  nothing  more  need  be  added 
on  the  subject.  The  substances  the  most 
likely  to  interfere  with  the  purity  of  the 
gum,  in  those  succulent  plants  that 
abound  with  mucilage,  are  for  the  most 
either  insoluble  in  water  or  coagulable  at 
a  boiling  heat ;  so  that  a  judicious  ma- 
nagement of  the  boiling  and  clarification 
will  generally  succeed  with  those  vegeta- 
bles where  the  mucilage  is  in  sufficient 
quantity  to  repay  the  trouble  of  extrac- 
tion. 

Another  species  of  native  mucilage, 
somewhat  differing  from  any  of  the  pre- 
ceding, is  gum  tragacanth.  This  is  a  white 
opaque  gum,  in  the  form  of  twisted  shi'eds, 
seldom  tree  from  visible  impurities,  and 
o.f  a  remarkably  tough  almost  horny  con- 


sistence, so  that  it  cannot  be  reduced  to 
fine  powder  without  considerable  labour. 
It  exsudes  from  the  stem  and  branches  ot 
a  very  thorny  shrub  (Astragalus  Traga- 
cantha,  Linn  j  which  grows  on  the  island 
of  Candia,  and  other  parts  of  the  Le- 
vant. 

The  juice  dries  in  the  sun,  and  being 
collected  by  the  shepherds,  is  sent  to  Eu- 
rope without  any  preparation.  It  differs 
from  gum-arabic  in  being,  properly  speak- 
ing, hardly  soluble  in  water,  but  when  it 
is  covered  with  water  it  swells  prodigious- 
ly in  the  course  of  some  hours,  and  ab- 
sorbs so  much  of  the  fluid  as  to  become 
soft  and  pulpy,  but  will  not  resolve  itself 
into  a  liquid  by  any  further  addition  of 
water.  In  this  soft  pulpy  state  it  will  rea- 
dily mix  with  other  mucilages,  and  may 
be  spread  thin  over  any  surface,  and  it 
then  dries  into  a  very  firm  cement.  It  is 
employed  much  in  bookbinding,  mixed 
with  paste,  and  is  found  to  make  a  very 
strong  cement. 

MULE.    See  Animals,  Domestic. 

MURIATIC  ACID  — If  a  small  retort 
or  a  proof  bottle  with  a  curved  tube  be 
half  filled  with  well  dried  common  sail, 
and  some  strong  sulphuric  acid  be  poured 
upon  it,  a  copious  effervescence  takes 
place,  and  the  elastic  fluid  thus  extricated 
appears  in  the  form  of  a  white  vapour  as 
soon  as  it  comes  in  contact  with  the  at- 
mosphere :  when  by  the  evolution  of  this 
gas  all  the  common  air  has  been  driven 
out  of  the  retort,  the  subsequent  portions 
of  gas  may  be  collected  in  the  usual  man^ 
per  in  glass  jars  filled  with  mercury,  and 
inverted  in  a  bath  of  the  same  fluid.  The 
air  thus  procured  is  known  among  che- 
mists by  the  name  of  muriatic  acid  gas  ; 
it  is  transparent,  colourless,  and  possess- 
ed of  the  same  mechanical  properties  as 
common  air  and  other  elastic  fluids.  Its 
specific  gravity,  according  to  Fontana,  is 
'  about  =  0  00. 09,  but  according-  to  Kir- 
wan,  is  ==  0.00231,  that  of  water  being; 
=1000  0,  and  of  atmospheric  air=0.00l23. 
It  has  a  peculiarly  suffocating  odour ;  to 
the  taste  is  extremely  sour  and  corrosive, 
and  affects  vegetable  colours  in  the  same 
manner  as  other  acids.  It  is  instanta- 
neously fatal  to  animal  life,  and  is  incapa- 
ble of  supporting,  combustion ;  this  pecu- 
liarity, however,  belongs  to  it,  that  if  a 
lighted  taper  is  plunged  into  a  jar  full  of 
it,  the  flame  is  considerably  enlarged,  and 
tinged  of  a  greenish  yellow  colour  before 
it  is  extinguished. 

Muriatic  acid  gas  is  not,  properly  speak- 
ing, combustible,  though  it  unites  without 
difficulty  with  a  considerable  proportion 
of  oxygen,  forming  oxy  muriatic  acid.  The 


MUR 


MLR 


(Amity  between  water  and  muriatic  acid 
is  very  powerful ;  even  when  this  sub- 
stance is  in  a  gaseous  state  it  holds  a  con- 
siderable quantity  of  water,  from  which 
it  cannot  be  freed,  otherwise  than  by  the 
decomposition  of  this  latter  substance.  If 
a  little  water  be  introduced  into  a  jar  of 
muriatic  acid  gas  standing  over  mercury, 
an  immediate  absorption  takes  place,  and 
the  whole  of  the  acid  suddenly  loses  its 
gaseous  state,  teat  being  at  the  same  time 
given  out.  A  similar,  though  not  so  sud- 
den an  effect,  is  produced  by  charcoal, 
soft  wood,  sponge,  and  various  other  po- 
rous bodies,  probably  in  consequence  of 
their  containing  moisture.  A  piece  of  ice 
introduced  into  muriatic  acid  gas  is  melt- 
ed as  rapidly  as  if  it  was  laid  on  a  hot  coal, 
in  consequence  of  the  liberation  of  caloric 
during  the  combination  of  the  water  and 
acid  If  alum,  or  any  other  9alt  contain- 
ing much  water  of  crystallization,  be  in- 
troduced into  this  acid  gas,  an  absorption 
takes  place,  and  the  salt  becomes  pulve- 
rulent, in  consequence  of  the  transfer  of 
the  greatest  part  of  its  water  to  the  acid. 
Iron  filings,  wax,  phosphorus,  sulphur, 
and  other  inflammable  bodies,  when 
brought  into  contact  with  muriatic  acid 
gas,  absorb  more  or  less  of  it,  and  the  re- 
sidue, after  washing  with  water,  is  inflam- 
mable ;  the  cause  of  which  will  be  ex- 
plained presently,  when  we  treat  of  the 
decomposition  of  this  acid.  Neither  azot 
nor  any  of  the  simple  or  compound  in- 
flammable gases,  have  any  action  on  mu- 
riatic acid ;  with  ammoniac al  gas,  how- 
ever, it  combines  instantaneously,  the  two 
airs,  if  rightly  proportioned  to  each  other, 
entirely  disappearing,  and  solid  muriat  of 
ammonia  is  the  result. 

Although  muriatic  acid,  when  in  the 
state  of  gas,  is  the  purest  form  in  which 
it  is  known,  yet  the  inconvenience  of  keep- 
ing and  applying*  any  substance  in  this 
state  being  very  great,  it  is  always  used, 
except  on  particular  occasions,  in  a  liquid 
form.  Liquid  muriatic  acid,  or  spirit  of 
salt,  is  prepared  in  the  following  manner. 
A  capacious  tubulated  retort  is  filled  about 
one-third  of  its  capacity  with  decrepitated 
common  salt  (muriat  of  soda),  and  the 
juncture  of  the  retort  with  the  receiver  is 
carefidly  closed  with  fat  lute ;  to  the  re- 
ceiver is  adapted  a  Woulfe's  apparatus, 
the  bottles  of  which  are  placed  in  a  frame 
or  small  cistern  for  the  sake  of  keeping 
them  cool  by  means  of  ice  and  water.  The 
"Woulfe  bottles  themselves  are  more  than 
half  filled  with  distilled  water,  and  then 
concentrated  sulphuric  acid,  in  the  pro- 
portion of  about  six  ounces  for  every 
pound  avoirdupois,  is  poured  upon  the 


salt  through  the  tubulure  of  the  retort, 

which  is  immediately  after  closed  with  its 
glass  stopper.  As  soon  as  the  acid  and 
salt  come  into  contact,  the  retort  and  re- 
ceiver are  filled  with  white  vapour,  and 
the  disengagement  of  muriatic  acid  goes 
on  for  some  time  without  the  application 
of  heat :  when  the  current  of  gas  through 
the  Woulfe  bottles  begins  to  slacken,  a 
pot  of  lighted  charcoal  should  be  placed 
tinder  the  retort,  gradually  increasing  the 
fire  till  at  a  very  low  red  heat  no  more 
gas  is  disengaged.  What  remains  in  the 
retort  is  now  dry  sulphat  of  soda,  and  the 
water  in  the  Woulfe  bottles  will  be  found 
to  be  more  or  less  impregnated  with  mu- 
riatic acid,  according  to  the  quantity  of 
salt  originally  made  use  of.  The  method 
pursued  in  the  manufacturing  laborato- 
ries in  England,  is  in  general  the  same  as 
that  mentioned  above,  but  with  a  greater 
simplicity  of  apparatus,  and  the  vessel  that 
performs  the  part  of  the  retort,  is  either 
of  earthenware  or  of  iron  ;  this  last,  how- 
ever, is  extremely  improper,  as  a  portion 
of  iron  always  rises  with  the  acid,  and 
thus  communicates  to  it  that  yellow  straw 
colour  which  distinguishes  common  mu- 
riatic acid.  In  Germany,  where  sulphuric 
acid  is  dearer  than  it  is  in  this  country,  the 
mode  of  manufacturing  this  acid  is  to 
mingle  accurately  one  part  of  common 
salt  with  four  of  dried  clay,  and  to  sub- 
ject the  mass  to  strong  ignition  in  iron  or 
earthen  vessels ;  at  a  high  temperature 
the  alkaline  base  of  the  salt  combines 
with  the  earth,  and  the  gaseous  acid  as  it 
passes  over  is  received  into  water  where 
it  is  condensed  in  the  usual  way. 

If  a  portion  of  water  be  confined  in  a 
jar  over  mercury,  and  muriatic  acid  gas 
be  let  up  into  it,  a  quantity  of  gas  equal 
in  weight  to  the  water  will  be  absorbed, 
while  its  bulk  will  be  increased,  accord- 
ing to  Dr.  Priestley,  from  1  to  1.5,  and  ac- 
cording to  Kirwan,  from  l.to  1.53:  hence 
the  specific  gravity  of  this  liquid  acid,  ac- 
cording to  the  former,  is  =  1.33,  and,  ac- 
cording to  the  latter,  ==  1.5  :  but  the  spe- 
cific gravity  of  the  strongest  muriatic  acid 
that  can  be  made  and  kept  in  the  common 
method,  does  not  exceed  at  60°  Fahr. 
1.196.  Pure  liquid  muriatic  acid  is  as 
colourless  as  water;  when  exposed  to  the 
air  it  emits  a  white  vapour ;  it  affects  the 
smell  and  taste  in  the  same  manner  as  the 
muriatic  gas  does  :  it  combines  with  the 
alkalies  and  earths,  forming  neutral  salts. 
Its  action  upon  iron  and  zinc  is  very  ra- 
pid, and  accompanied  by  a  copious  disen- 
gagement of  hydrogen  gas ;  at  a  boiling 
temperature  and  in  open  vessels  it  oxy- 
dases and  dissolves  copper,  tin,  bismuth., 


MUS 


MYR 


lead,  cobalt,  manganese,  antimony,  and 
arsenic ;  silver  is  also  aflected  by  it  though 
very  slightly ;  it  seems  to  have  no  action 
whatever  on  gold,  platina,  mercury,  tung- 
sten, molybdena,  tellurium  and  titanium. 
It  dissolves  all  the  metallic  oxyds,  and  is 
an  acid  of  remarkable  activity-  "When 
heated  for  some  time  in  closed  glass  tubes 
it  corrodes  them  very  sensibly,  taking  up 
the  oxyd  of  lead  from  the  white  glass,  and 
the  alkali  from  green  glass. 

MUM  AT  OF  SODA,  or  Common  Salt. 
— Common  salt  is  found  in  large  masses, 
or  in  rocks  under  the  eaith,  in  England 
and  elsewhere.  In  the  solid  form  it  is 
called  sal  gem  or  rock  salt.  If  it  be  pure 
and  transparent,  it  may  be  immediately 
used  in  the  state  in  which  it  is  found :  but 
if  it  contain  any  impure  earthy  particles, 
it  should  be  previously  freed  from  them. 
In  some  countries  it  is  found  in  incredible 
quantities,  and  dug  up  like  metals  from 
the  bowels  of  che  earth.  In  this  manner 
lias  this  salt  been  dug  out  of  the  cele- 
brated salt  mines  near  Bochnia  and  Wie- 
liczka,  in  Poland,  ever  since  the  middle  of 
the  13th  century,  consequently  above 
these  500  years,  in  such  amazing  quanti- 
ties, that  sometimes  there  have  been 
20,000  tons  ready  for  salt.  In  these 
mines,  which  are  said  to  reach  to  the 
depth  of  several  hundred  fathoms,  500 
men  are  constantly  employed.  The  pure 
and  transparent  salt  needs  no  other  pre- 
paration than  to  be  beaten  to  small  pieces, 
or  ground  in  a  mill  But  that  which  is 
more  impure  must  be  strained,  purified, 
and  boiled.  '  That  which  is  quite  impure, 
and  full  of  small  stones,  is  sold  under  the 
name  of  rock  salt,  and  is  applied  to  ordi- 
nary uses  ;  it  may  likewise  be  used  for 
strengthening  weak  and  poor  brine 
springs. 

Though  the  salt  mines  of  Wieliczka, 
near  Cracow  in  Poland,  have  long  asto- 
nished the  philosopher  and  traveller,  yet 
it  deserves  to  be  remarked,  that  the  quan- 
tity of  rock  salt  obtained  from  the  mines 
of  Northwich  is  greatly  superior  to  that 
obtained  at  Cracow.  The  bishop  of  Llan- 
daff'  affirms,  that  a  single  pit,  into  which 
he  descended,  yielded  at  a  medium  4000 
tons  of  salt  in  a  year,  which  alone  is  about 
two-thirds  of  that  raised  in  the  Polish 
mines.  This  rock  salt  is  never  used  on 
our  tables  in  its  crude  state,  as  the  Polish 
rock  salt  is.    See  Salt-making. 

MUST  OF  GRAPE.    See  Wine. 

MUSTARD— Mustard  is  a  plant  of 
which  there  are  seventeen  species,  three 
of  which  are  natives  of  Great  Britain ;  the 
sinapis  alba,  nigra,  and  arvensis. 

The  alba,  or  white  mustard,  which  is 


frequently  cultivated  as  a  salad  herb  for 
winter  and  spring  use,  produces  white 
seeds,  used  for  making  the  sauce  called 
mustard. 

The  nigra,  or  common  mustard,  which 
is  frequently  found  growing  naturally,  but 
is  also  cult  vated  in  the  fields  for  its 
brown  seed. 

The  arvensis  grows  naturally  on  arable 
land  in  many  parts  of  Great  Britain.  The 
seed  of  this  is  commonly  sold  under  the 
title  of  Durham  mustard-seed. 

The  white  and  brown  mustard-^eed  is 
mostly  imported  from  Holland,  though 
always  inferior  to  the  English  growth. 
Brown  seed  is  higher  in  value  than  the 
while,  and  is  chiefly  used  for  pickling. 

The  manufacture  of  mustard  flour  is 
made  by  grinding  the  grain,  and  sifting  it. 
It  is  an  article  of  considerable  consump- 
tion* 

MUSTY  CASKS.  Method  of  cleaning, 
according  to  M.  Eenormandes.  From 
the  Annules  des  Arts  et  Manufactures. 

The  author  mentions,  that  he  was 
taught  the  secret  by  a  countryman. — 
He  took,  says  he,  "cow  dung-  very  fresh, 
and  diluted  it  with  warm  water,  so  as  to 
make  it  sufficiently  liquid  to  pass  readily 
through  a  large  tunnel.  He  previously 
dissolved  in  this  water  4  lbs.  of  common 
marine  salt,  and  one  pound  of  alum.  The 
quantity  of  this  liquid  was  equal  to  about 
a  sixteenth  part  of  the  capacity  of  the 
cask.  He  put  the  whole  in  a  pot,  and 
heated  it  to  ebullition,  stirring  it  conti- 
nually with  a  wooden  spatula.  He  pour- 
ed the  hot  liquor  into  the  barrel,  bunged 
it  tight,  and  shook  it  five  or  six  minutes 
every  two  hours,  taking  care,  after  every 
shaking,  to  pull  out  the  bung,  when  a 
thick  vapour,  with  a  strong  smell  of  must, 
issued  from  it.  Twenty-four  hours  after- 
wards, he  rinsed  the  barrel  till  the  water 
came  from  it  perfectly  clear.  During- 
this  operation,  some  water  was  heated,  in 
which  had  been  put  two  pounds  of  salt, 
and  half  a  pound  of  alum,  which  he  pour- 
ed quite  hot  into  the  barrel ;  he  shook  it 
once,  as  in  the  former  operation,  and  left 
the  barrel  well  bunged.  Two  hours  after, 
the  water  being  still  warm,  he  emptied  it 
out,  leaving  the  barrel  to  drain,  and  bung- 
ed it  up  very  tight,  till  it  should  be  want- 
ed for  use.  A  greater  quantity  of  cow- 
dung,  salt,  and  alum,  than  the  above,  will 
not  injure  the  operation. — Cow-dung  must 
be  used,  that  of  oxen  is  useless. 

MYRTLE  WAX. — This  substance,  ob- 
tained from  the  myrica  cerifera,  has,  in 
part,  the  tenacity  of  bees-wax,  without  its 
unctuosity,  and  along  with  it,  in  some  de- 
gree, the  brittleness  of  resins.   Its  colour 


NAI 


NAN 


is  a  pale  green.  Specific  gravity  about 
2.015.  It  melts  at  109° ;  and  at  a  tempe- 
rature sufficiently  high,  burns  with  a  pe- 
culiarly clear,  white  flame,  producing 
little  smoke,  and  emitting  an  agreeable 
aromatic  smell.  Water  has  no  action 
upon  it.  About  four-fifths  of  it  are  solu- 
ble in  twenty  times  their  weight  of  alco- 
hol, at  a  boiling  heat ;  but  are  deposited 


by  cooling  and  standing  a  few  days.  Oil 
of  turpentine  softens  it,  and  by  the  assist- 
ance of  heat  dissolves  it.  Caustic  potash 
by  boiling  converts  it  into  a  soap.  The 
mineral  acids  act  upon  it,  though  feebly. 
From  all  its  habitudes  Dr.  Bostock  infers, 
that  it  is  a  fixed  vegetable  oil,  rendered 
concrete  by  the  addition  of  oxigen. 


N. 


NAILS. — The  manufacture  of  nails, 
forms  a  considerable  part  of  American 
industry.  It  is  not  necessary  to  detail 
the  manner  in  which  they  are  made, 
nor  to  describe  the  apparatus  usual- 
ly employed  for  making  them ;  both  of 
which  are  well  known.  Several  patents 
have  been  obtained  for  certain  improve- 
ments either  in  casting,  cutting,  or  other- 
wise making  them,  in  a  particular  man- 
ner ;  and  among  these  improvements, 
those  of  our  countrymen  rank  the  first. 
Nails  may  be  either  wrought,  cut,  or  cast. 
The  cut  nail,  however,  is  the  most  com- 
mon. Mr.  Finch  obtained  a  patent  for 
sundry  improvements  in  this  art,  or  trade, 


in  1790 ;  Mr.  CufTerd  also  in  the  same 
year;  and  Mr.  Spencer  in  1801,  all  from 
the  British  government.  For  information 
on  this  subject,  accompanied  with  plates 
of  the  apparatus,  the  reader  is  referred  to 
the  volumes  of  the  Repertory  of  Arts, 
especially  the  7th,  9th,  and  15th. 

NAIL  or  BOLT  DRAWER. — The  fol- 
lowing instrument  was  invented  by  Mr. 
Rich,  of  Great  Britain,  for  the  purpose  of 
drawing  nails  or  bolts ;  for  which  the  So- 
ciety for  the  encouragent  of  Arts,  in  1787, 
granted  him  a  premium  of  three  guineas. 

The  following  cut  will  exhibit  the  ma- 
chine. 


A,  B,  the  piece  of  timber,  in  which  the 
nail  «r  spike  C,  intended  to  be  drawn,  is 
inserted. 

D,  E,  the  shape  of  the  tool,  consisting 
of  a  lever,  D,  that  moves  on  a  solid  basis, 
in  the  form  of  a  segment  of  a  circle,  as 
at  E. 

F,  a  square  staple,  turning  on  a  centre, 
at  G :  and,  if  the  spike  to  be  drawn  be 
held  between  the  lever  and  the  staple,  any 
pressure  at  D  will  act  with  an  effect  pro- 
portionate to  the  distance  a  F,  and  Da,- 
and  the  workman  will  thus  be  enabled  to 


exert  a  very  great  force  against  the 
spike  C. 

NANKEEN  DYE.—Resides  the  obser- 
vations on  the  dyeing  of  a  nankeen  co- 
lour, given  under  the  article  Dyeing, 
and  some  account  of  the  preparation  un- 
der Iron,  the  following  paper,  by  Mr. 
Brewer,  we  have  extracted  from  the 
Transactions  of  the  Dublin  Society. 

Process  for  Dye'mg  Nankeen  Colour. 
Mix  as  much  sheep's  dung  in  clear  wa- 
ter as  will  make  it  appear  of  the  colour  of 


NAN 


NAN 


grass,  and  dissolve  in  clear  water  one 
pound  of  the  best  white  soap  tor  every 
ten  pounds  of  cotton-yarn,  or  in  that  pro- 
portion for  a  greater  or  lesser  quantity. 

Observe : — The  tubs,  boards,  and  poles, 
that  are  used  in  the  following  operations, 
must  be  made  of  deal ;  the  boiling-pan 
of  either  iron  or  copper. 

First  Operation. 

Pour  the  soap  liquor  prepared  as  above 
into  the  boiling-pan ;  strain  the  dung  li- 
quor through  a  sieve  ;  add  as  much 
thereof  to  the  soap  liquor  in  the  pan  as 
will  be  sufficient  to  boil  the  yarn  intended 
to  be  dyed  for  live  hours.  When  the  li- 
quors are  well  mixed  in  the  pan,  enter 
the  yarn,  light  the  fire  under  the  pan,  and 
bring  the  liquor  to  boil  in  about  two 
hours,  observing  to  increase  the  heat  re- 
gularly during  that  period.  Continue  it 
boiling  for  three  hours,  then  take  the  yarn 
out  of  the  pan,  wash  it,  wring  it,  and 
hang  it  in  a  shed  on  poles  to  dry.  When 
dry,  take  it  into  a  stove  or  other  room 
where  there  is  a  fire ;  let  it  hang  there 
until  it  be  thoroughly  dry. 

N.  B.  The  cotton  yarn,  when  in  the 
shed,  should  not  be  exposed  either  to  the 
rain  or  sun  :  if  it  is,  it  will  be  unequally 
coloured  when  dyed. 

Second  Operation. 
In  this  operation  use  only  one  half  of  j 
the  soap  that  was  used  in  the  last,  and  as 
much  dung  liquor  (strained  as  before  di- 
rected) as  will  be  sufficient  to  cover  the 
cotton  yarn,  when  in  the  pan,  about  two 
inches.  When  these  liquors  arc  well 
mixed  in  the  pan,  enter  the  yarn,  light 
the  fire,  and  bring  the  liquor  to  boil  in 
about  one  hour ;  then  take  the  yarn  out, 
wring  it  without  washing',  and  hang  it  to 
dry  as  in  the  former  operation. 

Third  Operation. 
This  operation  the  same  as  the  second 
in  every  respect. 

Fourth  Operation. 

For  every  ten  pounds  of  yarn  make  a 
clear  ley  from  half  a  pound  of  pot  or 
pearl  ashes.  Pour  the  ley  into  the  boil- 
ing-pan, and  add  as  much  clear  water  as 
will  be  sufficient  to  boil  the  yarn  for  two 
hours  ;  then  enter  the  yarn,  light  the  fire, 
and  bring  it  to  boil  in  about  an  hour.  Con- 
tinue it  boHing  about  an  hour,  then  take 
the  yarn  out,  wash  it  very  well  in  clear 
water,  wring  it,  and  hang  it  to  dry  as  in 
former  operations. 

N.  B.  This  operation  is  to  cleanse  the 
yarn  from  any  oleaginous  matter  that  may 


remain  in  it  after  boiling  in  the  soap  and 
dung  liquors. 

Fifth  Operation. 

To  every  gallon  of  iron  liquor  add  half 
a  pound  of  ruddle,  or  red  chalk  (the  last 
the  best)  well  pulverized. 

Mix  them  well  together,  and  let  the  li- 
quor stand  four  hours,  in  order  that  the 
heavy  particles  may  subside ;  then  pour 
the  clear  liquor  into  the  boiling  pan,  and 
bring  it  to  such  a  degree  of  heat  as  a  per- 
son can  well  bear  his  hand  in  it ;  divide 
the  yarn  into  small  parcels,  about  five 
hanks  in  each  j  soak  each  parcel  or  hand- 
ful very  well  in  the  above  liquor,  wring  it, 
and  lay  it  down  on  a  clean  deal  board. 
When  all  the  yarn  is  handed  through  the 
liquor,  the  last  handful  must  be  taken  up 
and  soaked  in  the  liquor  a  second  time, 
and  every  other  handful  in  succession  till 
the  whole  is  gone  through  ;  then  lay  the 
yarn  down  in  a  tub,  wherein  there  must 
be  put  a  sufficient  quantity  of  ley  made 
from  pot  or  pearl  ashes,  as  will  cover  it 
about  six  inches.  Let  it  lie  in  this  state 
about  two  hours,  then  hand  it  over  in  the; 
ley,  wring  it,  and  lay  it  down  on  a  clear 
board.  If  it  does  not  appear  sufficiently 
deep  in  colour,  this  operation  must  be  re- 
peated till  it  has  acquired  a  sufficient  de- 
gree of  darkness  of  colour :  this  done,  it 
must  be  hung  to  dry  as  in  former  opera- 
tions. 

N.  B.  Any  degree  of  red  or  yellow  hue 
may  be  given  to  the  yarn  by  increasing  or 
diminishing  the  quantity  of  ruddle  or  red 
chalk. 

Sixth  Operation. 
For  every  ten  pounds  of  yarn  make  a 
ley  from  half  a  pound  of  pot  or  pearl 
ashes  ;  pour  the  clear  ley  into  the  boiling- 
pan  ;  add  a  sufficient  quantity  of  water 
thereto  that  will  cover  the  yarn  about 
four  inches ;  light  the  fire,  and  enter  the 
yarn,  when  the  liquor  is  a  little  warm ; 
observe  to  keep  it  constantly  under  the  li- 
quor for  two  hours  ;  increase  the  heat  re- 
gularly till  it  come  to  a  scald ;  then  take 
the  yarn  out,  wash  it,  and  hang  it  to  dry 
as  in  former  operations. 

Seventh  Operation. 

Make  a  sour  liquor  of  oil  of  vitriol  and 
water;  the  degree  of  acidity  may  be  a 
little  less  than  the  juice  of  lemons  ;  lay 
the  yarn  in  it  for  about  an  hour,  then  take 
it  out,  wash  it  very  well  and  wring  it ; 
give  it  a  second  washing  and  wringing, 
and  lay  it  on  a  board. 

N.  B.  This  operation  is  to  dissolve  the 
metallic  particles,  and  remove  the  felrugi- 


NIC 


NIT 


nous  matter  that  remains  on  the  surface 
of  the  thread  after  the  fifth  operation. 

Eighth  Operation. 

For  every  ten  pounds  of  yarn  dissolve 
one  pound  of  best  white  soup  in  clear  wa- 
ter, and  add  as  much  water  to  this  liquor 
in  your  boiling-pan  as  will  be  sufficient  to 
boil  the  yarn  for  two  hours.  When  these 
liquors  are  well  mixed,  light  the  fire,  en- 
ter the  yarn,  and  bring*  the  liquor  to  boil 
in  about  an  hour.  Continue  it  boiling 
slowly  an  hour  5  take  it  out,  and  wash  it 
in  clear  water  very  well,  and  hang-  it  to 
dry  as  in  former  operations  :  when  dry  it 
is  ready  for  the  weaver. 

N.  13.  It  appears  to  us,  from  experi- 
ments, that  less  than  four  operations  in  the 
preparation  of  the  yarn  will  not  be  suffici- 
ent to  cleanse  the  pores  of  the  fibres  of  the 
cotton,  and  render  the  colour  permanent. 

NAPLES  YELLOW.  See  Colour 
Making. 

NAPTHA.    See  Bitumen. 

NATRON.    See  Soda  and  Barilla. 

NEALING.    See  Annealing. 

NEEDLE.  See  Manufacture  of 
Pins  and  Needles. 

NEEDLE,  Magnetic.  See  Magnet- 
ism. 

NICARAGUA  WOOD.    See  Dyeing. 

NICKEL. — This  is  a  metal  of  great 
hardness,  of  an  uniform  texture,  and  of  a 
colour  between  silver  and  tin ;  very  diffi- 
cult to  be  purified,  and  always  magneti- 
cal,  whence  it  has  been  supposed  to  con- 
tain iron  in  its  purest  state.  It  even  ac- 
quires polarity  by  the  touch.  It  is  mallea- 
ble, both  cold  and  redhot ;  and  is  scarce- 
ly more  fusible  than  manganese.  Its  ox- 
ides, when  pure,  are  reducible  by  a  suffi- 
cient heat,  without  combustible  matter  ; 
and  it  is  little  more  tarnished  by  heating 
in  contact  with  air,  than  platina,  gold,  and 
silver.  Its  specific  gravity*  when  cast  is 
8.279 ;  when  forged,  8  666*. 

We  do  not  know  that  this  metallic  sub- 
stance has  been  applied  to  any  use  ;  yet 
Fourcroy  supposes  it  is  employed  in  co- 
louring porcelain  or  enamels. 

Nickle  is  commonly  obtained  from  its 
sulphuret,  the  kupfernickel  of  the  Ger- 
mans, in  which  it  is  generally  mixed  also 
with  arsenic,  iron,  and  cobalt.  This  is 
first  roasted  to  drive  off  the  sulphur  and 
arsenic,  then  mixed  with  two  parts  of 
black  flux,  put  into  a  crucible,  covered 
with  muriat  of  soda,  and  heated  in  a  forge 
furnace.   The  metal  thus  obtained,  which  i 


is  still  very  impure,  must  be  dissolved  in 
dilute  nitric  acid,  and  then  evaporated  to  | 
dryness  ;  and  after  this  process  has  been 
repeated  three  or  four  times,  the  residuum 


must  be  dissolved  in  a  solution  of  ammo- 
nia  perfectly  free  from  carbonic  acid.  Be- 
ing again  evaporated  to  dryness,  it  is  now 
to  be  well  mixed  with  2  or  3  parts  of 
black  flux,  and  exposed  to  a  violent  heat 
in  a  crucible  for  half  an  hour  or  more. 

According  to  Richter,the  oxide  is  more 
easily  reduced  without  any  flux  ;  and  The- 
nard  is  of  a  similar  opinion.  Richter, 
however,  says  it  is  effected  more  speedily 
by  moistening  the  oxide  with  a  little  oil. 
Thenard  too  advises,  to  pour  oxigenized 
muriatic  acid  saturated  with  lime  on  the 
oxide  of  nickel,  and  shake  them  well  to- 
gether, before  the  ammonia  is  added ;  as 
thus  the  oxides  of  cobalt  and  iron,  if  pre- 
sent, will  be  so  much  saturated  with  oxi- 
gen,  as  to  be  insoluble  in  the  ammonia, 
and  consequently  mav  be  separated. 

NITRIC  ACID,  Nitrous  Acid,  A- 
qua  Fort  is  of  Commerce. — This  acid  is 
found  native,  united  with  potash,  and  with 
several  of  the  earths.  It  is  also  generat- 
ed in  several  chemical  processes,  and 
may  be  produced  by  the  direct  union  of 
its  two  constituent  parts,  azot,  and  oxy- 
gerty  in  sufficient  quantity  to  afford  satis- 
factory evidence  of  its  chemical  nature  ; 
but  for  the  purposes  of  the  laboratory  and 
manufacture,  it  is  always  prepared  from 
nitre,  by  the  addition  of  some  substance 
which  has  a  stronger  affinity  with  potasli 
than  the  nitric  acid  has,  assisted  by  distil- 
lation. 

The  most  ancient  way  of  procuring 
this  acid,  and  which  is  still  practised  in 
many  countries,  is  by  heating  strongly  a 
mixture  of  nitre  and  clay,  or  nitre  and 
green  vitriol,  in  earthen  or  iron  retorts, 
and  receiving  the  acid  vapour  in  proper 
vessels.  It  was  soon  found  that  alum  and 
some  other  vitriolic  salts  answered  the 
purpose  as  well  as  the  vitriol  of  iron,  and 
lastly  the  great  improvement  was  made 
of  employing  the  vitriolic  acid  alone, 
which  is  the  method  now  universally 
adopted  in  the  laboratory,  and  chiefly  in 
manufacture  in  Great  Britain,  where  this 
acid  is  generally  cheap 

The  way  of  procuring  the  nitrous  acid 
in  small  quantities,  is  the  following :  take 
a  plain  glass  retort  of  any  size,  put  into 
it  any  quantity  of  dry  purified  nitre  in 
powder  (which  need  not  be  very  fine) 
dropping  it  through  a  paper  funnel,  that 
none  may  lodge  in  the  neck  of  the  retort, 
and  fill  it  not  higher  than  at  most  two- 
thirds  of  the  capacity  of  the  body  of  the 
vessel,  when  the  nitre  lies  light  and  un- 
compressed. Then  pour  in  (through  a 
glass  funnel,  with  a  stem  reaching  nearly 
to  the  bottom)  concentrated  sulphuric 
acid  equal  to  about  half  of  the  weight  of 


NIT 


NIT 


the  nitre,  equally  guarding-  against  any 
lodgement  of  it  in  the  neck  of  the  retort. 
Then  lute  on  a  large  tubulated  glass  re- 
ceiver, and  cement  the  joinings  with  fat 
lute.  These  two  are  all  the  vessels  abso- 
lutely required,  but  the  tube  of  the  re- 
ceiver must  be  only  loosely  stopped,  or 
(what  is  a  belter  way)  it  should  dip  into 
an  empty  bottle  without  luting  the  join- 
ings. As,  however,  towards  the  end  of  the 
process,  much  acid  vapour  passes  off 
which  would  be  lost  in  the  common  way 
of  proceeding,  and  is  partially  condensi- 
ble  by  water,  one  or  two  bottles  of  the 
WoultVs  apparatus,  half  filled  with  wa- 
ter, may  be  added  to  the  receiver,  and 
the  absorption  tubes  carefully  placed,  so 
that  none  of  the  acidulous  water  may  be 
sucked  back  into  the  receiver,  and  mix 
with  the  stronger  acid.  The  retort  is 
then  to  be  placed  in  a  sand  bath,  and  the 
fire  applied  gradually. 

As  soon  as  the  nitre  and  sulphuric  acid 
mix,  faint  orange -yellow  fumes  arise,  but 
very  sparingly,  till  by  the  assistance  of 
heat  the  nitre  is  completely  dissolved  in 
the  acid.  When  this  mixture  begins  to 
get  hot,  the  fumes  increase,  and  long  wet 
streaks  appear  on  the  neck  of  the  retort, 
which  collect  and  fall  down  in  drops  in 
the  receiver.  The  heat  is  now  to  be  in- 
creased till  the  mixture  boils,  and  at  this 
point  of  gentle  ebullition  the  materials  are 
to  be  kept,  during  which  the  drops  of 
acid  fall  in  quick  succession  into  the  re- 
ceiver, and  the  receiver  itself  is  lined 
with  the  same  streaks  of  acid  drops.  To- 
wards the  middle  of  the  distillation,  when 
both  retort  and  receiver  are  filled  with 
the  acid  vapour,  the  colour  is  only  a  faint 
orange,  so  that  the  materials  within  the 
retort  can  be  seen  without  much  difficulty 
by  looking  down  (for  the  hot  sand  should 
be  heaped  up  as  high  as  possible,  and 
above  the  level  of  the  boiling  fluid)  and 
even  if  they  cannot  be  conveniently  seen, 
the  process  will  be  known  to  go  on  well 
by  the  gentle  uniform  hissing  noise  of  the 
boiling  materials,  and  the  moderately  ra- 
pid fall  of  condensed  drops  in  the  receiv- 
er, which  last  should  be  kept  quite  cold 
with  wetted  cloths  on  the  outside,  if  ne- 
cessary. During  all  this  time  little,  if 
any,  gas  or  vapour  of  any  kind  passes  be- 
yond the  large  receiver.  At  length  the 
vapour  in  the  retort  becomes  of  a  higher 
orange,  which  soon  (and  rather  suddenly) 
deepens  into  a  very  dark,  and  nearly 
opake,  orange-red,  so  that  the  materials 
can  no  longer  be  seen ;  and  a  little  after- 
wards these  begin  to  swell  considerably, 
and  to  rise  slowly  up  to  the  neck  of  the 
retort ;  and  if  this  was  at  first  more  than 
half  full,  the  hot  half-fluid  matter  is  apt 
VOL.  II. 


to  flow  over  into  the  neck,  and  thence  in- 
to the  receiver,  unless  the  heat  of  the  fur- 
nace be  rapidly  checked,  and  the  top  of 
the  retort  cooled  by  removing  the  upper 
part  of  the  sand.  The  distillation  is  then 
to  be  continued  with  the  heat  kept  up  as 
high  as  possible  without  boiling  over,  and 
the  whole  receiver  now  becomes  darkenr 
ed  with  red-orange  fumes,  which  find 
their  way  on  to  the  connected  bottles, 
where  they  are  chiefly  condensed  in  the 
water  through  which  they  are  forced.  At 
the  same  time,  however,  a  considerable 
quantity  of  gas  escapes;  which,  if  exa- 
mined, is  found  to  be  a  mixture  of  azote 
with  a  very  large  proportion  of  oxygen. 
When  nothing  further  is  given  out,  and 
the  heat  is  sufficient  nearly  to  redden  the 
bottom  of  the  retort,  the  process  is  con- 
cluded. 

The  products  of  this  distillation  are  :— 
a  quantity  of  strong  heavy  nitrous  acid, 
of  a  bright  yellow  colour,  emitting  co- 
pious orange-red  fumes,  of  an  excessively 
pungent  and  peculiar  smell,  and  of  the 
specific  gravity  of  about  1.5,  or  half  as 
heavy  again  as  water,  if  the  nitre  was  tho- 
roughly dried  before  it  was  put  into  the 
retort,  and  the  sulphuric  acid  was  very 
concentrated.  The  quantity  of  this  acid, 
is  on  an  average  about  half  the  weight  of 
the  nitre  employed.  Besides  this  the  wa- 
ter that  receives  the  nitrous  vapour  is 
converted  into  a  weak  acid  liquor  of  a 
blue-green  colour. 

The  substance  remaining  in  the  retort 
concretes  into  a  beautifully  white  spongy 
saline  mass,  consisting  of  sulphat  of  pot- 
ash with  a  small  excess  of  sulphuric  acid. 
This  may  be  dissolved  out  of  the  retort 
by  hot  water,  if  the  heat  has  not  been  so 
intense  as  to  melt  the  glass  and  the  salt 
into  a  kind  of  opake  vitreous  mass. 

The  proportions  of  nitre  and  vitriolic 
acid  here  given,  are  two  of  the  former  to 
one  of  the  latter.  Even  a  somewhat  small- 
er quantity  of  vitriolic  acid  will  disengage 
all  the  acid  of  the  nitre,  but  the  remain- 
ing sulphat  of  potash  is  harder,  and  the 
heat  required  for  distillation  is  greater;  so 
that  if  it  be  a  preferable  object  to  save  the 
retort,  not  less  than  half  the  weight  of 
sulphuric  acid  should  be  employed.  If 
this  is  increased  to  two-thirds,  which  is 
sometimes  done,  the  distillation  is  still  ea- 
sier, but  the  nitric  acid  contains  some  sul- 
phuric acid,  from  which  indeed  it  is  sel- 
dom free  till  further  rectified. 

To  prepare  only  a  few  ounces  of  the 
acid,  a  sand-heat  is  not  necessary,  but  the 
retort  may  be  heated  by  a  lamp. 

The  nitrous  acid  thus  prepared  is  very 
strong  and  fuming,  and  the  least  drop 
stains  the  hands  yellow  almost  inunedi-. 


Ml 


NIT 


jttelj.  When  heated  to  boiling-,  it  gives 
out  abundance  of  red  nitrous  vapour,  and 
if  kept  boiling  for  a  quarter  or  half  an 
hour  (which  in  a  narrow-mouthed  flask 
can  be  done  without  much  loss  of  acid)  it 
becomes  when  cold,  limpid  and  colourless 
as  water,  and  now  no  longer  fames.  To 
preserve  it  colourless,  it  should  be  kept  in 
a  dark  place,  as  the  light  gradually  re- 
stores the  colour. 

Thus  then  there  are  two  forms  or  spe- 
cies of  this  acid,  viz.  the  orange-yellow 
fuming  acid,  and  the  pale  limpid  -y  and  the 
former  is  more  accurately  termed  ill  mo- 
dern chemistry  nitrous  acid,  and  the  latter 
nitric.  The  precise  difference  between 
the  two  will  be  presently  noticed  ;  but  it 
may  be  here  observed,  that  the  nitrous 
appears  to  be  the  nitric  holding  a  quanti- 
ty of  red  nitrous  vapour  in  solution. 

Common  nitrous  acid  contains,  besides 
nitrous  vapour,  a  quantity  of  muriatic  and 
of  sulphuric  acid ;  the  former  arising  from 
&  small  admixture  of  common  suit,  or 
more  commonly  of  muriat  of  potash  with 
the  nitre  ;  and  the  latter  from  the  volatili- 
zation of  part  of  the  sulphuric  acid  add- 
ed. It  is  of  importance  often,  both  in 
manufacture  and  in  experiment,  to  get 
rid  of  these  foreign  aeids,  which  may  be 
done  in  the  following  way:  the  sulphuric 
acid  is  got  rid  of  by  re-distilling  the  acid 
upon  about  an  eighth  or  tenth  of  pure  ni- 
tre in  a  moderate  heat,  by  which  the  sul- 
phuric acid  is  detained ;  or  else  nitrat  of 
lead  may  be  added  to  the  mixed  acid, 
which  will  cause  the  sulphuric  to  separate 
in  the  form  of  an  insoluble  sulphat,  after 
which  the  clear  acid  may  be  simply  de- 
canted off,  or  (what  is  much  better) 
should  be  re -distilled. 

To  separate  the  muriatic  acid,  nitrat  of 
silver  may  be  dropped  in  gradually,  till 
all  the  muriatic  acid  falls  down  as  muriat 
of  silver,  after  which  the  clear  nitrous 
acid  may  be  considered  as  pure,  or,  what 
is  better,  should  be  redistilled 

The  manufacture  of  this  acid  in  the 
great  way  is  now  performed  with  equal 
simplicity  in  England,  and  with  the 
same  materials.  The  process  is  the  fol- 
lowing- :  rough  nitre  is  first  recrystallized, 
then  the  crystals  are  put  (without  pound- 
ing) into  a  iarge  glass  body,  to  which  is 
added  half  the  weight  of  sulphuric  acid ; 
a  glass  pipe  is  then  luted  to  the  body,  and 
made  to  communicate  with  an  empty  re- 
ceiver ;  and  from  this  by  three  or  four  more 
pipes  with  other  receivers  half  full  of  wa- 
ter, but  in  this  case  the  pipes  do  not  dip 
in  the  water.  Heat  is  then  applied,  and 
the  strong-  acid  condenses  in  the  empty- 
receiver,  whilst  the  acid  vapour  unites 
with  the  water  of  the  others,  forming  the 


common  aquafortis.  To  purify  the  strong 
acid  from  the  muriatic,  the  following  sim- 
ple method  is  found  sufficient :  a  small 
quantity  of  distilled  water  is  added  to  se- 
veral pounds  of  the  acid,  which  causes  a 
great  production  of  heat  and  a  sudden 
gust  of  nitrous  fumes,  and  in  these  fumes 
ali  the  muriatic  acid  escapes,  being  more 
volatile  than  the  nitric  acid.  By  subse- 
quent boiling,  the  rest  of  the  nitrous  va- 
pour is  got  rid  of,  and  the  acid  that  re- 
mains is  nearly  pure  nitric  acid,  of  about 
1.5  specific  gravity.  The  residuary  sul- 
phat of  potash  is  mostly  sold  to  the  aluni- 
makers  in  Scotland 

The  furnace  and  apparatus  of  an  aqua 
fortis  distiller  consist  chiefly  of  a  long  iron 
trough  filled  with  sand,  in  which  the  re- 
torts are  buried  in  two  rows,  standing1 
back  to  back,  and  under  which  is  a  long 
brick  furnace  to  heat  the  sand.  Each  re- 
tort has  its  own  receiver — Sometimes,  in- 
stead of  glass  retorts,  very  thick  iron  pots 
are  substituted  with  advantage.  These 
will  last  a  very  considerable  time  before 
thev  are  so  much  worn  as  to  be  unservice- 
able. 

Nitrous  acid  is  also  prepared  in  the 
large  way  in  some  countries  by  distilling 
nitre  and  clay,  sometimes  nitre  and  mar- 
tial vitriol.  The  apparatus  for  both  is  the 
same,  namely,  large  earthen  pear-shaped 
pots,  in  which  the  materials  are  heated, 
and  earthen  globes  for  receivers*  The 
pots  are  ranged  in  a  long  furnace  in  a  dou- 
ble row,  as  already  described.  When 
clay  is  the  material  used,  a  harsh  vitriolic 
clay  is  selected,  which  is  first  well  dried 
in  a  small  oven,  then  beaten  to  rough 
powder^  and  sifted.  About  five  parts  of 
nitre  are  taken  to  twelve  of  the  clay,  and, 
when  well  mixed,  the  mass  is  wetted  ei- 
ther with  water  or  with  the  weakest  aci- 
dulous phlegm  of  former  distillations. 
The  mixture  is  then  put  into  the  pots,  and 
the  fire  is  kindled  and  kept  up  with  those 
precautions  which  practice  alone  can 
teach,  and  the  distillation  continued  till 
all  the  acid  has  come  over,  and  the  pots 
are  nearly  red  hot.  The  acid  procured 
in  this  way  is  generally  pretty  good,  but 
must  undoubtedly  be  much  weaker  than 
when  made  with  sulphuric  acid  and  nitre, 
since  it  is  not  uncommon  to  obtain  nearly 
as  much  nitrous  acid  as  the  weight  of  ni- 
tre employed.  Indeed  it  is  obvious,  that 
it  must  contain  all  the  moisture  originally- 
left  in  the  clay,  as  well  as  that  employed 
in  the  mixture  of  the  ciay  and  nitre.  The 
affinity  that  acts  here  in  the  production 
of  the  acid,  must  be  that  of  the  clay  for 
the  alkali  of  the  nitre,  when  strongly- 
heated.  Besides  this,  the  clays  used  are 
considerably  vitriolic,  which  also  assists 


NIT 


NI1T 


in  the  expulsion  of  the  nitrous  acid.  The 
residue  in  the  retort  is  a  hard  half-fused 
earthy  mass,  now  turned  to  a  deep  red 
(owing1  to  the  complete  oxydation  of  the 
iron  of  the  clay)  and  consisting-  of  all  the 
earths  of  the  clay,  the  alkali  of  the  nitre, 
and  a  little  sulphat  of  potash,  which  last 
must  be  separated  by  boiling  water.  This 
residue  is  called  cement  earth  of  aqua  for- 
tis, and  is  only  used  as  a  red  earth  in 
staining-  tiles,  bricks,  &c. 

The  process  for  making  aqua  fortis  by 
martial  vitriol  (which  is  a  very  good  me- 
thod, and  much  used  on  the  continent  of 
Europe)  is  very  simple.  The  vitriol  is  first 
calcined  till  it  falls  into  a  white  powder,  by 
which  it  loses  nearly  half  its  weight  of  mere 
water,  but  little  or  none  of  its  acid.  The 
calcined  vitriol  is  then  mixed  with  about 
Us  own  weight  of  pure  nitre,  and  the  mix- 
ture is  put,  in  some  works,  iruo  earthen,  in 
others  into  iron  pots,  to  which  glass  re- 
ceivers are  well  luted  (but  with  a  small 
vent-hole,  for  the  uncondensible  vapour  to 
escape  when  opened)  and  the  fire  is  gra- 
dually raised  to  redness,  during  which  the 
acid  distils  over.  In  this  as  in  other  dis- 
tillations of  this  acid,  a  fat  lute  made  of 
clay  and  linseed  oil  is  generally  employ- 
ed.  The  acid  procured  in  this  method  is 
more  ruddy  and  fuming  than  in  any  other, 
so  as  to  be  almost  brown  and  opake,  and 
in  the  process  the  receiver  is  often  found 
starred  with  crystalline  rays,  which  again 
melt  down.  These  are  probably  sulphu- 
ric acid  driven  off"  by  the  violence  of  the 
heat,  and  saturated  with  nitrous  vapour, 
which  (as  will  be  elsewhere  mentioned) 
renders  this  acid  crystallizable.  The  re- 
sidue of  this  distillation  is  a  mixture  of 
sulphat  of  potash  and  red  oxyd  of  iron, 
which  is  easily  gx>t  out,  unless  the  nitre 
was  mixed  with  common  salt,  in  which 
case  it  adheres  very  closely  to  the  vessel 
The  sulphat  of  potash  is  got  out  by  lixi- 
viation  with  hot  water,  and  the  insoluble 
residue  is  a  perfect  oxyd  of  iron,  of  a 
blood-red  colour,  called  colcothar,  and, 
when  well  washed  and  sifted,  is  much 
used  by  the  looking-glass  makers  to  po- 
lish their  mirrors. 

Other  substances  are  occasionally  used 
to  disengage  the  nitrous  acid  from  nitre, 
where  they  can  be  procured  cheap.  Sul- 
phat of  magnesia  is  very  useful  for  this 
purpose,  and  in  the  neighbourhood  of 
salt-works  it  may  be  sometimes  obtained 
economically  in  sufficient  quantity.  In 
this  case  there  appears  to  be  first  a  dou- 
ble decomposition  of  the  ingredients,  by 
which  sulphat  of  potash  and  nitrat  of 
magnesia  are  produced,  and  then  the  heat 
drives  the  nitric  acid  off,  so  that  the  resi- 
due contains  both  sulphat  of  potash  and 


uncombined  magnesia.  It  is  from  vary 
few  other  substances,  however,  that  the 
nitric  acid  can  be  expelled  by  heat  tinde- 
composed,  for  when  the  nitrated  alkalies 
and  most  other  nitrated  earths  are  heat- 
ed, the  acid  is  decomposed  almost  at  first, 
and  the  products  are,  not  nitric  acid,  but 
the  elements  of  this  acid  disunited.  Hence 
it  is  that  nitre  alone  cannot  be  made  to. 
yield  its  acid  by  heat. 

The  distilling  vessels  are  made  either 
of  glass,  or  earth,  or  iron.  The  former 
is  undoubtedly  tiie  best  material,  but  is 
expensive  and  liable  to  accidents.  Iron, 
retorts,  when  made  very  thick  at  bottom, 
last  a  considerable  time,  but  the  acid  gra- 
dually acts  upon  them,  and  produces 
much  red  nitrous  vapour,  which  causes 
the  acid  to  be  always  excessively  fuming' 
and  high-coloured.  In  some  parts  of 
Wirtcmberg  it  appears  that  they  have  a 
way  of  lining  the  iron  pots  with  an  ena- 
mel glazing,  which  must  unite  all  the-ad- 
vantages  of  iron  and  glass. 

We  shall  now  give  the  preparation  of 
this  acid  according  to  the  formula  of  the 
colleges.  The  Edinburgh  college  recom- 
mend two  parts  of  nitre,  and  one  of  oil. 
of  vitriol,  for  distillation ;  the  London, 
sixty  ounces  of  nitre,  and  twenty-nine 
ounces  of  oil  of  vitriol ;  and  the  Dublin, 
six  pounds  of  nitre,  and  three  pounds  of 
vitriolic  acid.  The  specific  gravity  of  the 
acid  differs  considerably :  thus  the  Edin- 
burgh college  make  it  1550  to  1000  ;  the 
London  and  Dublin  the  same;  but  expe- 
riments make  the  concentrated  acid  much 
lower.  The  diluted  nitrous  acid  of  the 
colleges,  which  is  made  by  mixing  equal 
parts  of  nitrous  acid  and  water,  is  the 
same  as  double  aqua  fortis  of  the  shops. 
The  single  aqua  xortis  is  about  half  the 
strength  of  the  double. 

The  preparation  of  nitric  acid,  of  the 
Edinburgh  college,  consists  only  in  ex- 
pelling the  nitrous  gas  from  the  nitrous 
acid,  as  the  nitrous  differs  from  the  nitric 
in  holding  nitrous  gas  in  solution. 

Richter's  process  for  preparing  colour* 
less  nitric  acid,  is  said  to  be  preferable.  It 
consists  in  distilling  a  mixture  of  nitre, 
manganese,  and  sulphuric  acid;  in  the 
proportion  of  7  lbs.  of  nitre,  2oz.  of 
manganese,  and  about  41bs.  of  theacid.^ 

We  do  not  conceive  it  of  importance  in 
this  work,  to  notice  the  chemical  compo- 
sition, nor  the  properties,  of  this  acid.  In- 
formation of  this  kind  may  be  found  in 
scientific  treatises  on  chemistry.  Nitric 
acid,  down  to  the  common  aqua  fortis,  is 
much  used  in  the  arts,  particularly  for 
etching  on  copper,  and  for  dissolving  tin 
as  a  mordant  in  dveing. 

N1TRQ-MURIATIC  ACID.  Jona  7l>- 


NIT 


NIT 


gia. — The  term  nitro-muriatic  acid  is  not 
meant  to  designate  any  particular  acid  or 
modification  of  acid,  but  simply  a  mixture 
of  nitric  or  nitrous  and  muriatic  acid,  or 
sometimes  muriat  of  ammonia,  which 
when  united,  produce  a  very  important 
agent  in  many  chemical  operations.  It  is 
particularly  as  a  solvent  for  gold  that  this 
combination  (which  is  very  ancient)  has 
been  known,  and  hence  it  was  termed  by 
the  alchemists  aqua  regta,  (gold  being 
with  them  the  king  of  metals)  and  is  near- 
ly the  only  substance  that  can  dissolve 
this  noble  metal  The  composition  of  the 
aqua  reg-ia,  fitted  to  dissolve  gold,  has 
been  described  under  that  metal.  Platina 
also,  like  gold,  is  insoluble  in  either  of 
these  acids  singly,  but  yields  to  a  mix- 
ture of  the  two,  though  in  different  propor- 
tions. Antimony  also  is  scarcely  soluble 
in  any  acid  but  the  nitro-muriatic,  and  the 
composition  of  the  mixture  the  best  fitted 
ibr  this  purpose,  is  still  different  from  the 
others. 

Dr.  Priestley  has  found  that  a  very 
powerful  aqua  regia,  which  dissolves  gold 
with  great  rapidity,  may  be  formed  by  im- 
pregnating liquid  muriatic  acid  with  the 
nitrous  acid  vapour.  The  proportion  of 
constituent  parts  here  widely  differs  from 
those  of  the  common  aqua  regia  for  gold, 
which  last  is  usually  made  by  three-fourths 
of  nitric,  and  one  fourth  of  muriatic  acid  ; 
whereas  in  making  the  other  acid,  the  li- 
quid muriatic  acid  hardly  increases  in 
bulk  by  saturation  with  the  nitrous  va- 
pour. Dr.  Priestley  also  tried  to  form  a 
nitro-muriatic  acid  that  would  dissolve 
gold,  by  impregnating  nitrous  acid  with 
muriatic  acid  gas,  but  without  success,  as 
the  liquor  would  not  touch  this  metal.  As 
soon  as  the  muriatic  acid  receives  the  ni- 
trous vapour,  it  changes  from  a  pale  straw 
to  a  deep  orange,  much  deeper  than  ni- 
trous acid  alone  can  be  brought  to. 

Aqua  regia  is  now  made  by  a  direct 
mixture  of  nitric  and  muriatic  acids,  as 
before  observed,  and  generally  in  the  pro- 
portions stated.  It  was  formerly  prepared 
by  dissolving  sal  ammoniac,  or  common 
salt,  in  aquafortis. 

NITRE.  Saltpetre.  Nit  rat  of  potash- 
Nitre  being  an  important  article  of  com- 
merce and  manufacture,  we  shall  dwell  at 
some  length  on  its  formation  and  purifica- 
tion ;  and  particularly  on  the  means  of 
obtaining  it  in  the  United  States. 

Nitre  is  a  neutral  salt,  composed  of  ni- 
tric acid  and  potash  in  a  state  of  perfect 
mutual  saturation.  Its  primitive  crystal- 
line form  is  that  of  a  rectangular  octohe- 
dron,  composed  of  two  pyramids  applied 
base  to  base,  in  such  a  manner  that  two 
opposite  sides  of  the  upper  pyramid  form 


with  the  corresponding  sides  of  the  lower 
one,  angles  of  120°,  while  the  two  other 
opposite  sides  form  with  their  correspond- 
ing ones,  angles  of  111°.  This  figure, 
however,  is  of  very  rare  occurrence. 
W  hen  the  summits  of  the  pyramids  are 
deeply  truncated,  the  result  is  a  bevilled 
rectangular  table,  which  is  by  no  means 
unfrequent.  But  the  most  usual  form 
which  this  salt  assumes  is  that  of  the  com- 
mon quartz  crystal,  viz..  a  strait  six  sided 
prism,  terminated  at  each  extremity  by  a 
six-sided  pyramid.  The  specific  gravity 
of  nitre,  according  to  Newton,  is  =  1.9.  It 
has  a  sharp,  saline,  and  cooling  though 
disagreeable  taste.  When  fully  crystal- 
lized it  is  very  brittle,  and  the  larger  pris- 
matic crystals,  if  held  in  the  warm  hand, 
will  crack  across  with  a  very  audible 
noise.  It  generally  attracts  a  little  mois- 
ture on  exposure  to  the  air,  but  this  is 
probably  to  be  attributed  to  the  casual 
mixture  of  a  small  portion  of  deliquescent 
salt.  With  regard  to  the  degree  of  solubility 
of  nitre  in  water  of  different  temperatures 
there  exist  some  contradictions  that  re- 
quire to  be  cleared  up :  according  to 
Bergman,  this  salt  is  soluble  in  seven 
times  its  weight  of  water  at  the  usual 
temperature,  and  in  about  its  own  weight 
of  boiling  water ;  from  the  experiments  of 
Hassenfratz,  however,  it  appears  that  a 
hot  saturated  solution  of  nitre,  after  being 
cooled  down  to  61°  Fahr.  and  remaining 
at  this  temperature  twenty-four  hours, 
holds  nearly  one-fourth  of  its  weight  of 
salt,  and  at  54Q  Fahr.  about  dne-sixth  of 
its  weight:  according  to  Beaume,  four 
ounces  of  boiling  water  will  take  up  tea 
ounces  of  nitre,  when  the  solution  is  made 
in  a  matrass  ;  but  if  a  bason,  or  any  other 
open  vessel  is  made  use  of,  a  pellicle  be- 
gins to  form  at  the  surface  of  the  liquor, 
when  it  contains  water  and  salt  in  equal 
proportions.  The  following  table  of  the 
specific  gravity  and  composition  of  solu 
tions  of  nitre  in  water,  at  60°  Fahr.  has 
been  constructed  by  Hassenfratz. 

Sp.  gr.  of  solution  Proportion  of  Nitre  in 

at  61°  Fahr.  100  parts  of  solution 

1.006  ...  1 

1.012  ...  2 

1018  -  3 

1.024  -  4 

1.0.30  -  5 

1.035  -.-  6 

1.040  -       -       -  7 

1.046  ...  8 

1.053  -  9 

1.059  10 

1.065  11 

1072  -  12 

1.078  -      -       -  .33 

1.085  -      -       -  14 


NIT 


NIT 


Sp.  gi\  of  solution  Proportldn  of  Nhre  in 

at  61°  Falir.  100  parts  of  solution. 

1.091        ---  15 
1.098        ...  16 
1105        ...  17 
1.111        ...  18 
1.118  19 
1.125       ...  20 
1.132       ...  21 
1.138       ...  22 
1.145        ...  23 
1.152        ---  24 
1.158  25 
If  a  saturated  solution  of  nitre  is  boiled 
strongly,  and  more  especially  if  the  boil 
ing  temperature  is  raised  by  the  addition 
of  any  deliquescent  salt,  a  very  notable 
proportion  of  the  nitre  is  volatilized  with 
the  water. 

Nitre  is  readily  fusible  at  a  heat  almost 
equal  to  that  of  melting  zinc,  and  may  be 
kept  for  a  considerable  time  at  this  tem- 
perature, without  undergoing  any  change, 
except  a  slight  loss  of  weight  from  part- 
ing with  its  water  of  crystallization;  a 
piece  of  charcoal  may  even  be  immersed 
in  it  without  producing  any  detonation. 
When  poured  out  on  any  flat  surface,  it 
presently  congeals  into  a  white  translu- 
cent mass,  commonly  known  by  the  name 
of  crystal  mineral. 

The  following  is  the  composition  of  this 
salt  and  the  proportions,  according  to 
Bergman. 

49  Potash 
33  Nitric  acid 
18  Water 

100 

According  to  Wenzel,  100  parts  of  nitre 
contain 

48.13  Potash 

51.87  Acid  and  water 


100.00 


But,  according  to  Kirwan,  100  parts  of 
crystallized  nitre,  dried  at  70°  Fahr.  are 
composed  of 

51.8  Potash 
44  Acid 
4  2  Water 


100.0 


and  this  estimate  being  incidentally  con- 
firmed by  other  experiments  of  Berthollet 
and  of  Kehys  probably  very  near  the  truth. 

The  uses  of  nitre  are  very  important 
It  is  employed  in  prodigious  quantities  in 
the  manufacture  of  gunpowder,  and  in  all 
kinds  of  pyrotechnical  compositions.  It 
is  the  only  salt  from  which  nitric  acid  is 


habitually  made,  both  in  the  largo  and 
small  way ;  it  is  also  largely  consumed  in 
the  preparation  of  sulphuric  acid  from  the 
combustion  of  sulphur.  When  mixed 
with  common  salt,  it  adds  to  the  efficacy 
of  the  latter  in  preserving  animal  flesh 
from  decay  ;  it  is  employed  by  the  glass, 
maker  and  the  goldsmith,  and  is  in  con- 
stant use  m  the  laboratory. 

We  now  proceed  to  treat  of  the  natural 
history  and  manufacture  of  nitre,  as  car- 
ried on  in  various  countries,  but  chiefly  in 
France,  where  its  production  has  been 
more  an  object  of  philosophical  investiga- 
tion than  in  any  other  country. 

Nitre  may  be  considered  both  as  a  natu- 
ral and  artificial  product.  Native  nitre, 
mineralogically  speaking,  is  a  substance; 
of  very  recent  formation.  It  appears  to 
occur  in  two  different  repositories :  the 
first  of  these  is  limestone,  and  the  second, 
egetable  soil.  The  calcareous  repository 
is  either  a  peculiar  variety  of  secondary 
floetz  limestone,  or  calcareous  tufa,  or 
chalk,  or  indurated  marl.  In  these  rocks 
it  occurs  as  a  thin  granular  crust,  or  au 
efflorescence  of  minute  spicular  crystals, 
overspreading  the  outside,  and  particular- 
ly lining  the  inside  of  the  caverns,  both 
natural  and  artificial,  with  which  these 
rocks  abound.  Hence  probably  is  derived 
its  ancient  name  saltpetre  (Sal  petra,  rock 
salt).  Calcareous  strata,  containing  nitre, 
are  found  in  various  parts  of  South  Ame- 
rica, in  some  districts  of  France,  in  the 
county  of  Bamberg,  and  at  Hamburg  near 
Wurtzburg.  But  the  most  celebrated  re- 
pository of  native  nitre  is  the  Pulo  of  Mol- 
fetta,  in  the  province  of  Puglia,  in  the  king- 
dom of  Naples.  The  Pulo  is  a  deep  ca- 
vity, in  the  form  of  an  inverted  cone,  pro- 
duced by  the  falling  in  of  several  large 
natural  caverns,  and  communicating  late- 
rally with  other  caverns,  both  natural  and 
artificial,  that  yet  remain  entire.  All  the 
strata  in  which  these  excavations  occur, 
are  of  hard  secondary  limestone,  abound- 
ing with  the  remains  of  organized  bodies. 
The  whole  of  these  caves,  at  the  time  the 
Abbe  Fortis  called  the  public  attention  to 
them,  were  lined  with  an  efflorescent 
crust  of  nitre,  more  than  an  inch  in  thick- 
ness, which  after  being  scraped  off,  was 
again  renewed  in  the  course  of  a  few  days 
in  constant  succession.  Thin  fragments 
of  stone  were  often  falling  down,  being 
forced  from  their  place  by  the  crystalliza  - 
tions of  nitre  beneath  them ;  the  substance 
of  the  rock  also,  to  the  depth  of  a  foot  or 
more  from  the  surface,  was  richly  im- 
pregnated with  the  salt,  which  might  be 
separated  by  lixiviation;  but  specimens 
taken  from  a  greater  depth,  seem  to  con- 
tain no  nitre  ready  formed,  at  least  boil- 


NIT 


NIT 


any  It  appears,  however,  from  the  testi- 
mony ot'Dolomieu,  that  a  piece  of  this  rock 
after  lying-  for  two  months  in  a  dry  cabi 
net,  became  covered  with  a  thin  crust  of 
nitre.  Specimens  of  the  nitrous  crust 
from  the  Pulo  have  been  analysed  both 
by  Klaproth  and  Pelletier,  and  the  results 
agree  full  as  well  as  can  be  expected  in 
the  examination  of  a  substance  so  liable 
to  slight  variations  in  its  composition. 


Kiapr. 
425.5 
2. 


254.5 
304. 

986.0 
14. 


Pelletier. 
407.5  Nitre 

  Muriated  potash 

267  Muriats 

20.8  Sulphats,  soluble 

cold  water 
96-7  Sulphat  of  lime 
410    Curbonat  of  lime 


—  9617 


Loss 


1000.     —  1000. 


ing  water  was  incapable  of  dissolving-  out  being-  swept  ofT,  is  renewed  every  other 

day  at  particular  seasons  of  the  year. 
The  soil  of  those  lands  in  which  it  is 
less  abundant  is  raked  up  into  small 
heaps,  and  mixed  with  the  scrapings  of 
roads  and  cattle  stalls,  and  after  being 
exposed  for  a  certain  time  to  the  action 
of  the  air,  is  lixiviated :  the  earthy  resi- 
due is  mixed  with  fresh  earth,  and  after 
two  years  affords  as  large  a  produce  of 
nitre  as  at  first. 

In  many  nitrous  soils  the  acid  which 
they  contain  is  combined,  for  the  most 
part,  with  lime  instead  of  potash,  so  that 
the  produce  of  real  nitre  which  they  af- 
ford by  the  usual  mode  of  treatment  is 
very  small :  long  experience,  however, 
has  taught  the  nitre -makers  in  every 
country  where  these  soils  occur,  to  re- 
medy this  defect  by  the  addition  of  wood- 
ashes.    The  rationale  of  this,  though 
wholly  unknown  to  the  greater  number 
of  those  who  practise  it,  is  sufficiently  oh- 
vious  to  the  chemist;  the  carbonated  al- 
kali of  the  ashes,  and  the  calcareous  ni- 
trat  of  the  soil,  mutually  decompose  each 
other,  and  carbonated  lime  and  nitrated 
potash  is  the  result.    Many  of  the  nitrous 
soils  in  India  require  this  alkaline  addi- 
tion, as  well  as  those  of  China,  and  other 
parts  of  Asia.    Much  of  the  nitrous  soil 
in  the  Crimea  and  Ukraine  also  is  of  this 
description  :  in  appearance  it  resembles 
common  black  vegetable  mould,  except 
that  it  is  more  unctuous  to  the  touch,  and 
is  so  light  and  of  such  little  coherence,  as 
to  be  converted  to  a  loose  dust  by  a  few 
days  of  dry  weather.    Those  parts  of  the 
Crimea  that  have  been  long  uncultivated, 
and  especially  the  artificial  mounds  that 
have  served  for  burial  places,  and  the 
scites  of  towns,  are  selected  by  the  nitre- 
makers.   The  soil  being  dug  up,  is  mixed 
with  about  one-fifth  bv  measure  of  wood- 
ashes,  and  lixiviated,  in  perforated  casks, 
in  the  usual  way:  the  liquor  thus  pro- 
duced, when  concentrated  by  repeated 
lixiviations,  is  mixed  with  the  mother 
water  of  a  preceding  crystallization,  and 
boiled  down  for  24  hours,  removing  from 
time  to  time  the  common  salt  and  muria- 
ted potash  that  separates  during  the  pro- 
cess ;  it  is  now  transferred,  while  hot,  into 
shallow  coolers,  in  order  to  crystallize, 
which  it  does  in  24  hours  more.  The 
rough  crystals  being  drained,  are  again 
dissolved  in  water,  and  the  product  of  the 
second  crystallization  is  a  nitre  somewhat 
impure,  but  yet  in  a  fit  state  for  the  mar- 
ket. Four  hundred  cubic  feet  of  the  mix- 


The  second  repository  of  native  nitre  is 
vegetable  soil  It  is  asserted  by  some 
chemists,  especially  those  who  maintain 
that  nitre  is  a  product  of  vegetation,  that 
all  soils  contain  nitre  in  proportion  to  their 
fertility  :  Mr.  Beaume  lixiviated  carefully 
36  specimens  of  fertile  soil,  and  did  not 
obtain  a  particle  of  nitre  from  any  one  of 
them.  There  is  no  country  in  Europe, 
the  soil  of  which  is  so  rich  in  this  salt  as 
Spain-  It  is  asserted  by  Bowles,  that 
nearly  a  third  of  the  uncultivated  lands 
in  the  eastern  and  southern  provinces  of 
this  kingdom,  afford  it  in  abundance  un- 
der the  following  simple  management. 
The  land  is  ploughed  twice  or  thrice  du- 
ring the  winter  and  spring,  to  the  depth 
cf  three  or  four  inches;  it  lies  fallow  the 
whole  summer,  and  about  the  middle  of 
the  autumn,  the  soil  having-  been  thus  ex- 
posed to  the  full  action  of  the  air,  is  cart- 
ed off  and  lixiviated :  the  liquor  is  then 
boiled  down  in  the  usual  manner,  and  af- 
fords, by  cooling,  a  quantity  of  nitre  mixed 
with  from  20  to  40  per  cent,  of  common 
salt. 

A  considerable  part  of  the  soil  in  Lower 
Hungary  is  richly  impregnated  with  nitre, 
and  several  of  the  wells  and  springs  are 
incapable  of  being  used  as  drink  on  ac- 
count of  their  containing  from  two-thirds 
to  four  per  cent,  of  this  salt. 

Many  of  the  lands  in  India,  especially  j 
in  the  vallies  of  the  great  rivers,  are  ex- 1 


ceedingly  abundant  in  nitre  In  the  pre- 
sidency of  Calcutta  alone  between  7  and  !  ture  of  earth  and  wood-ashes,  afford  42  lbs 
8000  tons  are  annually  manufactured,  j  of  nitre  of  the  first  crystallization,  which 
Sometimes  it  covers  the  surface  of  the  I  by  the  subsequent  refining  is  reduced  to 
soil  with  a  saline  efflorescence,  which  I  39  lbs. 


NIT 


NTT 


Dr.  Brown  in  the  Trans.  Phil.  Soc.  vol. 
vi,  speaking  of  a  nitre  cave  in  Crooked 
creek,  in  Kentucky,  observes  that  "  the 
quality  of  the  nitre  procured  from  the 
earth  in  calcareous  caverns,  is  universally 
believed  to  be  different  from  that  which 
is  found  in  the  sand  rocks.  I  have  not 
been  able  to  ascertain,  with  any  degree  of 
precision,  the  quantity  annually  manufac- 
tured in  this  state,  nor  the  number  of  ca- 
verns which  are  known  to  contain  it.  I 
have,  however,  visited  several  of  the  most 
remarkable  of  them,  and  from  the  best 
information  I  could  procure,  1  have  form- 
ed the  following  estimate  I 

lbs.  of  Nitre. 

The  great  cave  on  Crooked  creek, 
a  branch  of  Rock  castle,  sup- 
posed to  contain    .    -    .    .  1000000 

Scott's  cave,  two  miles  distant 

from  the  great  cave     .    .    .  200000 

Davis's  cave-,  six  miles  distant 

from  the  great  cave    ....  50000 

Two  other  caves,  within  a  mile  of 

the  great  cave   20000 

A  cave  on  Rough  creek,  a  branch 

of  Green  river   10000 

Besides  these,  which  I  have  had  an  op- 
portunity of  examining,  I  have  heard  of 
many  others  in  various  parts  of  the  state : 
some  of  which  are  esteemed  very  rich  in 
nitre,  and  are  said  to  be  of  great  extent. 

The  great  cave  on  Crooked  creek,  in 
Madison  county,  is  situated  about  sixty 
miles  south-east  of  Lexington.  It  has 
two  mouths,  which  are  646  yards  distant 
from  each  other,  and  about  150  yards 
from  a  large  creek,  which  winds  round 
the  hill  through  which  the  cave  affords  a 
commodious  passage  for  horses  and  wag- 
gons. The  general  level  of  the  floor  of 
the  cave  is  80  feet  above  the  creek.  The 
average  height  of  the  arch  is  ten  feet, 
though  in  many  places  it  rises  to  fifty  or 
sixty.  The  breadth  of  the  passage  is  ge- 
nerally about  forty  feet,  in  some  parts  it 
is  seventy  or  eighty  feet.  The  floor  has 
the  appearance  of  a  large  public  road, 
which  has  been  much  frequented.  The 
ceiling  is,  in  most  places,  smooth,  with 
but  few  incrustations  or  stalactites-  In 
some  of  the  chambers,  however,  there  are 
appearances  of  Gothic  rudeness  and  irre- 
gularity, which  are  truly  sublime.  When 
these  vast  chambers  are  sufficiently  illu- 
minated by  the  torches  and  lamps  of  the 
workmen,  they  present  scenes  so  uncom- 
mon and  so  romantic,  that  the  most  stu- 
pid beholder  cannot  contemplate  them 
without  expressions  of  the  greatest  aston- 
ishment. During  the  winter  season,  the 
effect  of  these  scenes  is  greatly  increased 
ky  a  stream  of  water,  which,  issuing  from 


a  small  opening  in  the  arch  of  the  cave, 
ibout  twenty  feet  above  the  floor,  and 
falling  into  a  basin,  occasions  a  noise 
which,  in  these  calm  regions,  can  be  heard 
at  a  great  distance,  and  echoing  from  arch 
to  arch,  fills  the  mind  with  the  idea  of 
some  mighty  cataract. 

The  temperature  of  this  cave,  during 
the  last  winter,  (the  coldest  we  have  had 
for  several  years)  was  generally  529  Fan. 
Sometimes  the  mercury  rose  as  high  as 
B7°t  but  never  sunk  to  the  freezing  point, 
When  the  thermometer  was  placed  at  any 
considerable  distance  within  the  cave.  In 
one  chamber,  however,  the  heat  was  fre- 
quently so  great  as  to  be  disagreeable. 
About  sixty  paces  from  the  south  en- 
trance, a  passage  leading  from  the  main 
avenue  conducts  you  to  this  chamber, 
i  which  is  nearly  circu  ar,  and  about  twenty 
feet  in  diameer.  The  arch  over  this  part 
of  the  main  avenue,  and  that  over  the  pas- 
sage leading  to  the  warm  chamber,  are 
.  equally  elevated ;  but  the  ceiling  of  the 
chamber  is  twenty  or  thirty  feet  higher. 
'  As  you  approach  the  chamber,  the  floor 
gradually  rises  until  it  ascends  above  the 
j  level  of  the  arch  of  the  passage.  As  soon 
•  as  you  ascend  above  that  level,  you  per- 
ceive the  air  uncommonly  warm,  even 
j  when  the  temperature  of  the  passage  is 
|  near  the  freezing  point.    The  air  which 
fills  the  main  avenue  in  summer  and  au- 
|  tumn  is  forced  into  this  chamber,  when- 
i  ever  the  external  atmospheric  air  becomes 
j  so  much  condensed  by  cold  as  to  rush 
into  the  mouth  of  the  cave;  and  when- 
J  ever,  during  the'  winter,  any  portion  of 
air  in  the  main  avenue,  where  the  passage 
leads  off,  is  accidentally  heated  by  fires, 
or  by  carrying  torches  or  lamps  through 
i  the  cave,  as  tiiis  heated  air  cannot  escape 
by  the  mouth  of  the  cave  (for  the  arch  de- 
scends towards  the  mouth)  it  ascends  into 
this  chamber,  and  rises  to  the  ceiling, 
where  it  must  remain  until  the  external 
air,  and  that  ita  the  passage  and  avenue, 
acquire  a  higher  temperature  than  the 
air  in  the  chamber.    This  chamber  then 
is  constructed  precisely  upon  the  princi- 
ples of  the  Russian  vapour-bath,  so  mi- 
nutely described  by  count  Rumford. 

During  the  winter  season,  the  walls  and 
floor  of  this  cave  remain  perfectly  dry; 
but  in  summer  innumerable  drops  of 
water  collect  upon  the  rocks,  and  trickle 
down  upon  the  floor,  which  sometimes 
becomes  as  moist  as  a  bed  of  mortar. 
This  is  particularly  the  case,  during  very 
hot  weather,  when  the  atmosphere  is  load- 
ed with  vapours.  I  collected  a  quantity 
of  the  liquid  condensed  upon  the  rocks, 
and  found  that  it  possessed  the  same  pro- 
perties with  the  liquor  obtained  bv  lixi- 


NIT 


NIT 


viating  the  earth  on  the  floor  of  the  cave. 
It  M  ould  appear  from  this  fact,  that  the 
nitric  acid  is  formed  in  the  cave,  and  is 
condensed  upon  the  rocks,  the  lime  of 
•which  it  dissolves.  But  in  what  manner 
this  nitric  acid  is  formed,  1  confess  myself 
wholly  ignorant,  as  there  are  no  sub- 
stances in  a  state  of  putrefaction,  within 
the  cave,  which  could  yield  the  requisite 
supply  of  nitrogene  gas.  It  is  to  be  re- 
marked, that  the  whole  of  the  water  con- 
densed upon  the  rocks,  does  not  taste  of 
the  nitrate  of  lime.  A  great  part  of  it  is 
quite  insipid,  although  dropping  upon 
earth  which  is  rich  in  nitre ;  and.  many 
parts  of  the  cavern  have  been  found  so 
completely  filled  with  clay,  that  it  is  not 
easy  to  conjecture  how  it  was  possible  for 
atmospheric  air  to  reach  them;  and  this 
clay  too  is  strongly  impregnated  with  ni 
trate  of  lime.  The  depth  of  the  earth  on 
the  floor  of  this  cave  has  never  yet  been 
ascertained.  In  some  places  the  work- 
men have  dug  down  fifteen  feet,  and  the 
earth,  even  at  that  depth,  still  contains 
nitre.  It  is  commonly  supposed  that, 
throughout  the  cave,  every  bushel  of 
earth  contains  at  least  one  pound  of  nitre. 
In  many  places  it  will  yield  more  than  two 
pounds  to  the  bushel.  Formerly  the  earth 
was  taken  out  of  the  cave  and  lixiviated 
near  the  stream ;  at  present  hoppers  are 
erected  in  the  cave,  and  the  earth,  after 
lixiviation,  is  left  to  be  impregnated  again 
with  nitrat  of  lime ;  but  what  Length  of 
time  will  be  requisite  to  saturate  it,  has 
not  yet  been  ascertained. 

The  workmen  have  different  modes  of 
forming  an  opinion  with  regard  to  the 
quantity  of  nitre  with  which  the  earth 
may  be  impregnated.  They  generally 
trust  to  their  taste ;  but  it  is  always  con- 
sidered as  a  proof  of  the  presence  of  nitre, 
when  the  impression  made  on  the  dust  by 
the  hand  or  foot,  is  in  a  very  short  time 
effaced.  Where  the  nitre  is  very  abun- 
dant, the  impression  made  to-day  will  be 
scarcely  visible  to-morrow.  Where  there 
is  a  great  deal  of  sand  mixed  with  the 
dust,  it  is  commonly  believed  that  a  small 
quantity  of  potash  will  suffice  for  the  sa- 
turation of  tiie  acid. 

The  method  of  making  saltpetre,  usual- 
ly practised  in  Kentucky,  is  as  follows  : 

The  earth  is  dug  and  carried  to  hop- 
pers of  a  very  simple  construction,  which 
contain  about  fifty  bushels,  cold  water  is 
poured  on  it  from  time  to  time,  and  in  a 
day  or  two  a  soluion  of  the  salts  runs  into 
troughs  placed  beneath  the  hoppers.  The 
lixiviation  is  continued  as  long  as  any 
strength  remains  in  the  earth.  The  li- 
quor is  then  put  into  iron  kettles,  and 
heated  to  ebullition ;  it  is  afterwards 


thrown  upon  a  hopper  containing  wood- 
ashes,  through  which  it  is  suffered  to  fil- 
trate. As  the  alkaline  part  of  the  ashes 
is  discharged  before  the  nitrate  passes 
through,  the  first  runnings  of  this  hopper 
are  thrown  back;  and  after  some  time, 
the  clear  solution  of  nitrate  of  potash  runs 
out,  mixed  with  a  white  curd,  which  set- 
tles at  the  bottom  of  the  trough.  This 
clear  liquor  is  boiled  to  the  point  of  crys- 
tallization, then  settled  for  a  short  time, 
and  put  into  troughs  to  crystallize,  where 
it  remains  twenty -four  hours ;  the  crystals 
are  then  taken  out,  and  the  mother-water 
thrown  upon  the  ash-hopper,  with  the 
next  running  of  the  nitrate  of  lime.  When 
the  quantity  of  the  nitrate  of  lime  is  too 
great  for  the  portion  of  ashes  employed, 
the  workmen  say  their  saltpetre  is  in  the 
"grease,"  and  that  they  do  not  obtain  a 
due  quantity  of  nitre.  If  there  has  been 
too  great  a  proportion  of  ashes  employed, 
they  say  it  is  in  the  "  ley"  and  when  it  is 
left  to  settle  previous  to  crystallization,  a 
large  quantity  of  salt  will  be  deposited  in 
the  settling  troughs,  which  they  call  "  cu. 
bic  salts"  These  salts  are  again  thrown 
upon  the  ash -hoppers,  and  are  supposed 
to  assist  in  precipitating  the  lime  from  the 
nitrate  of  lime,  and,  in  the  opinion  of  the 
workmen,  are  changed  into  pure  saltpetre. 
They  consider  this  salt  as  nitre  killed,  as 
they  express  it,  by  the  excessive  strength 
of  the  ley.  To  make  100  pounds  of  good 
saltpetre  at  the  great  cave,  eighteen  bush- 
els of  oak  ashes  are  necessary  ;  ten  of  elm, 
or  two  of  ashes  made  by  burning  the  dry 
wood  in  hollow  trees.  In  the  discovery 
of  the  value  of  this  latter  kind  of  ashes, 
the  philosophers  and  chemists  of  Europe 
have  been  anticipated  by  the  saltpetre- 
makers  of  Kentucky.  The  earth  in  some 
caves  does  not  require  half  this  quantity 
of  ashes  to  precipitate  the  impure  salts. 

When  wood-ashes  cannot  be  readily  ob- 
tained near  the  caves,  the  liquor  which 
runs  from  the  earth  in  the  hoppers  is  boil- 
ed down  to  the  point  of  crystallization, 
and  suffered  to  become  solid  by  cooling. 
In  this  form,  which  is  called <l  thick  stuff," 
it  is  transported  to  a  part  of  the  country 
where  ashes  can  be  procured,  dissolved 
in  ley  sufficiently  strong  to  precipitate 
the  lime,  settled  in  troughs,  and  then  boil- 
ed down  and  crystallized.  This  thick 
stuff  is  extremely  liable  to  deliquesce  in 
warm  moist  weather,  and  is  therefore 
commonly  melted  down,  and  put  into 
casks  before  it  is  carried  from  the  caves. 
Horned  cattle  are  very  fond  of  it,  and  a 
small  portion  of  it  is  almost  instantly  fatal 
to  them.  Those  who  have  had  frequent, 
opportunities  of  seeing  cattle  perish  in 
this  way,  remark  that  the  blood,  whqn 


NIT 


NIT 


dra  wn  from  their  veins,  is  of  a  very  black 
colour,  and  flows  with  great  difficulty.  A 
substance  possessing-  such  active  proper- 
ties, might  deserve  the  attention  of  expe- 
rimental physicians,  and  may  possibly 
merit  a  share  of  that  praise  which  has 
been  so  liberally,  and  perhaps  so  injudi- 
ciously, bestowed  upon  the  nitrate  of  pot- 
ash. 

After  these  observations  on  the  calca- 
reous nitre-beds  in  Kentucky,  and  the 
modes  commonly  employed  for  obtaining 
that  salt,  I  shall  mention  some  of  the  most 
remarkable  circumstances  which  have 
come  to  my  knowledge,  relative  to  the 
rock  ore,  or  sand  rocks,  which  yield  nitre 
supposed  to  possess  peculiar  qualities. 

These  sand  rocks  are  generally  situated 
at  the  head  of  a  ravine  or  narrow  valley, 
leading  up  a  sleep  hill  or  mountain  :  as- 
cending the  streamlets  which  run  through 
these  valleys,  the  banks  close  in  upon  you 
and  become  perpendicular.  The  rocks 
are  frequently  from  sixty  to  one  hundred 
feet  in  height,  and  jutting  over  their  bases, 
which  rest  on  a  calcareous  stratum,  often 
forming  a  shelter  large  enough  to  secure 
a  thousand  men  from  the  inclemencies  of* 
the  weather.  During  the  winter  season  a 
small  rill  is  precipitated  from  the  top  of 
these  rocks,  and  in  summer,  water  gene- 
rally issues  from  between  the  silicious  and 
calcareous  strata.  These  sand  rocks, 
which  probably  once  formed  a  complete 
upper  stratum,  have  been  for  ages  ex- 
posed to  the  destructive  operations  of 
rains  and  frosts,  and  as  they  crumble  off, 
are  carried  by  torrents  into  the  plain:.;  and 
rivers  beneath.  The  summits  of  all  the 
hills  in  the  vicinity  of  Rock-castle,  Lick- 
ing and  Sandy,  are  still  covered  by  masses 
of  these  rocks,  which,  from  their  beauty 
and  variety  of  figure,  might,  at  a  small 
distance,  be  mistaken  for  the  ruins  of  Go- 
thic cathedrals,  or  baronial  castles.  Vast 
blocks  of  them  have  roiled  down  into  the 
vallics,  at  a  period  of  time  so  remote  that 
they  are  now  covered  by  trees  of  a  luxu- 
riant growth.  These  rocks,  when  broken 
perpendicularly,  present  a  surface  consist- 
ing of  strata  so  irregular,  with  regard  to 
their  position,  and  so  different  in  colour, 
and  in  the  size  of  the  particles  of  sand, 
that  it  is  impossible  to  doubt  of  their  Nep- 
tunian origin.  The  minute  inspection  of 
them  never  fails  of  awakening  in  the 
mind  the  recollection  of  the  shore  of  some 
vast  lake,  where  the  rage  of  the  winds  and 
t  iie  waves  has  piled  up  hills  of  sand,  which 
time  consolidates  into  rock. 

Several  years  ago  the  saltpetre-makers 
discovered  that  the  sand  and  rubbish,  shel- 
tered from  rains  by  these  rocks,  contained 
a  rich  impregnation  of  nitre,  and  that  only 
VOL.  II. 


a  small  portion  of  ashes  was  necessary  for 
its  purification.  They  soon  after  found, 
that  the  sand  rock  itself  tasted  strongly 
of  saltpetre,  and  immediately  commenced 
the  new  method  of  working. 

After  blowing  off  large  blocks  of  the 
rock,  they  break  them  into  small  pieces 
with  hammers,  and  throw  them  into  ket- 
tles containing  boiling  water  :  as  soon  as 
the  rock  falls  into  sand  by  the  action  of" 
the  hot  water  upon  it,  they  put  it  into 
hoppers  and  wash  out  all  the  nitre  by  fre- 
quent additions  of  cold  water ;  this  solu- 
tion is  boiled  down  and  crystallized  with- 
out any  mixture  of  ashes  or  potash.  Some- 
times, when  the  mother-water  has  been 
very  often  added  to  fresh  solutions  of  the 
nitre,  they  find  it  necessary  to  use  a  very 
small  quantity  of  ashes. 

I  have  been  informed  by  Mr.  Fowler, 
that  he  and  his  associates  have  made  salt- 
petre at  twenty -eight  different  rock-houses 
or  caverns,  from  which  they  have  obtain- 
ed about  100,000  lbs  of  nitre ;  all  these 
are  situated  on  the  north  side  of  Kentucky 
river,  within  seventy  miles  of  Lexington. 
He  remarks  that  he  has  never  seen  a  rock 
facing  the  north  or  west,  which  was  very 
rich  in  nitre.  He  has  always  desisted  from 
working  a  rock  when  it  failed  to  yield  him 
ten  pounds  to  the  bushel  of  sand.  He  has 
often  obtained  twenty  or  thirty  pounds  per 
bushel.  He  assured  me  that  he  once  dis- 
covered a  mass  of  very  pure  nitre,  which 
was  found  to  weigh  1600  pounds.  Mr. 
Foley,  another  saltpetre-maker,  found  one 
containing  100 pounds:  another  mass  was 
found  on  Rock-castle,  which  report  says 
weighed  500  pounds.  I  have  now  in  my 
possession  a  solid  mass  of  native  nitrat  of 
potash  of  singular  purity,  which  weighs 
three  pounds;  it  is  more* than  four  inches 
in  thickness,  and  is  only  a  small  portion 
of  a  block  of  nitre  found  last  summer  on 
Licking  river:  I  have  likewise  a  number 
of  smaller  specimens,  which  I,  myself,  pro- 
cured from  the  different  caves  which  I  vi- 
sited some  weeks  ago.  These  are  gene- 
rally found  between  the  rocks  which  have 
fallen  from  the  cliff,  or  the  crevices  of 
those  rocks  which  still  remain  in  their 
primitive  situation.  The  rocks  which  con- 
tain the  greatest  quantity  of  nitre  are  ex- 
tremely difficult  to  bore,  and  are  general- 
ly tinged  with  a  brownish  or  yellow  ochre 
colour.  Sometimes  they  contain  an  oxyde 
like  manganese,  and  sometimes  great 
quantities  of  iron  ore,  which  resembles 
the  bark  of  the  scaly-bark  hickory,  sur- 
rounded by  a  finely  powdered  brown  ox- 
ide. At  some  of  these  rock-houses  three 
hands  can  make  one  hundred  pounds  of 
good  nitre  daily;  but  forty  pounds  may  be 
considered  as  the  average  product  of  the 
T 


iMT 


KIT 


labour  of  three  men  at  those  works  which 
1  had  an  opp  rtunity  of  visiting. 

The  workmen  being  badly  provided 
with  tools  and  apparatus,  desert  a  rock 
whenever  its  size  or  hardness  renders  it 
difficult  for  them  to  manage  it,  and  go  in 
quest  of  a  new  establishment  Several 
caves  and  rocks  which  these  strolling  che- 
mists have  deserted,  still  contain  many 
thousand  pounds  of  nitre.  These  men 
are  continually  searching  for  masses  of 
pure  nitre,  or  rich  veins  of  ore,  by  which 
much  of  their  time  is  unprofitably  dissi- 
pated. Still,  however,  most  of  our  salt- 
petre-makers find  it  their  interest  to  work 
the  sand  rock  rather  than  the  calcareous 
caverns,  which  last  yields  a  mixture  of  ni- 
trate of  potash  and  nitrate  of  lime.  The 
rock  salpetre  is  greatly  preferred  by  our 
merchants  and  powder-makers,  and  com- 
mands a  higher  price." 

In  the  paper  on  the  manufactures  of  the 
United  States,  the  following  fact,  as  it  re- 
spects the  quantity  of  nitre  made  in  this 
Country,  appears,  viz.  Virginia  prepares 
annually  59,175  lbs.;  Kentucky,  201,937  ; 
Massachusetts,  23,600 ;  East  Tennesee, 
17,531 ;  West  Tennesee,  144,895  ;  making 
nearly  half  a  million  pounds  of  home-made 
nitre,  as  good  as  that  brought  from  foreign 
parts. 

Before  the  general  use  of  gunpowder  in 
war,  the  produce  of  native  nitre  was  abun- 
dantly sufficient  to  supply  the  European 
demand  for  this  article  ;  but  when,  in  con- 
sequence of  the  universal  adoption  of 
fire-arms,  the  consumption  of  this  salt 
was  prodigiously  increased,  it  became  an 
important  object  for  every  nation,  and 
especially  those  that  were  the  least  com- 
mercial, to  encourage  by  every  method 
the  domestic  manufacture  of  nitre.  Eve- 
ry kind  of  soil  that  had  the  least  resem- 
blance to  the  nitre  soils  of  Spain  and  In- 
dia,, was  examined  by  lixiviation,  and  by 
degrees  it  was  ascertained  that  the  sur- 
face soil  of  farm-yards,  of  cattle-stalls,  of 
cellars,  of  privies,  and  other  places  long 
exposed  to  the  vapours  of  putrefying  ani- 
mal matter,  afforded,  when  mixed  with 
wood-ashes  and  lixiviated,  a  considerable 
quantity  of  nitre     It  was  also  discover- 
ed that  the  plaister,  mortar,  and  what  is 
included  under  the  general  term  brick- 
rubbish  of  old  houses,  was  capable  of 
yielding  this  salt  by  a  similar  experiment. 
In   consequence  of  this  discovery,  all 
these  substances  were  claimed  by  the 
crown  in  most  of  the  countries  of  Europe, 
and  granted  to  societies  of  saltpetre-ma- 
kers, incorporated  for  the  purpose  of  sup- 
plying the  public  magazines  of  the  coun- 
try with  this  indispensable  commodity. 
England  and  Holland  were  soon  able  to 


supply  themselves  at  an  easy  rate  with  ni- 
tre, by  means  of  their  commercial  con^ 
nexions  with  India  and  China,  and  there- 
fore attended  only  a  very  short  time  to  the 
domestic  preparation  of  this  salt.  France, 
Germany,  and  the  northern  states  of  Eu- 
rope, on  the  other  hand,  importing  but  a 
small  quantity  of  nitre  in  proportion  to 
their  wants,  have  always  encouraged  its 
manufacture  by  every"  method  in  their 
power.  In  the  former  of  these  countries, 
especially,  the  privileges  of  the  saltpetre- 
makers  were  so  extensive  and  so  rigor- 
ously enforced,  as  to  occasion  much  petty 
tyrar.ny  and  vexation,  besides  operating 
as  a  direct  discouragement  to  agricul- 
ture. These  manufacturing  companies 
were  allowed  to  take  away  without  com- 
pensation all  the  nitrous  soils  that  they 
could  discover  :  hence  when  a  house  was 
pulled  down,  such  part  of  the  old  mate- 
rials and  old  foundation  soil  as  suited  their 
purpose  was  selected  from  the  rest,  and 
carried  oft"  by  them :  they  had  also  the 
right  of  digging  up  once  a  year  the  earth- 
en floors  of  every  out-house,  and  in  some 
provinces  even  of  the  inhabited  cottages  : 
the  farmer's  yards  were  subject  to  the 
like  troublesome  visitations,  by  which  he 
was  deprived  of  a  considerable  quantity 
of  his  best  manure  ;  and  every  parish  or 
district  was  obliged  besides  to  furnish  a 
certain  amount  of  wood-ashes.  These 
terrible  means  of  annoyance  were  placed 
by  the  crown  in  the  hands  of  the  formers 
general,  and  by  them  were  intrusted  to 
inferior  agents,  more  disposed  to  exercise 
them  so  as  to  obtain  from  those  in  their 
power  a  pecuniary  composition,  than  to 
exert  their  privileges  for  the  public  ad- 
vantage ;  the  consequence  of  which  was, 
that,  notwithstanding  the  trouble  and  ex- 
tortion by  which  individuals  were  thus 
severely  harassed,  the  annual  produce  of 
niire,  at  the  accession  of  Turgot  to  the 
ministry,  scarcely  exceeded  one  half  of 
what  it  had  amounted  to  half  a  century 
before.  An  important  reform,  however- 
was  introduced  by  this  able  statesman 
the  privilege  of  digging  up  the  floors  and 
cellars  of  inhabited  houses  was  abolished, 
the  requisitions  of  fuel  and  wood-ashes 
were  restrained,  and  the  administration  oi 
this  department  was  taken  from  the  far- 
mers general,  and  intrusted  to  a  particu- 
lar commission,  of  which  Lavoisier  and 
Clouet  were  leading  members;  a  conside- 
rable sum  of  money  was  placed  at  the 
disposal  of  the  Royal  Academy  of  Sci- 
ences, to  be  distributed  as  prizes  by  this 
body  to  the  authors  of  the  best  memoirs 
on  the  preparation  of  saltpetre;  in  conse 
j  quence  of  which  various  importani 
changes  took  place  in  the  managemei v 


NIT 


MT 


And  construction  of  artificial  nitre -beds, 
and  the  refining"  of  their  produce.  By 
these  means  the  yearly  amount  of  nitre 
made  in  France  w  as  increased  during"  the 
period  from  1775  to  1785,  from  1,800,000 
lbs.  to  3,500,000  lbs  Four  years  after 
this  period  the  revolution  war  commenc- 
ed, for  the  supply  of  which  a  prodigious 
quantity  of  gunpowder  was  demanded, 
while  all  the  requisite  nitre  was  obliged  to 
be  drawn  from  domestic  supplies.  To 
meet  this  exigency,  the  knowledge  and 
personal  superintendance  of  the  ablest 
chemists  of  Paris  was  directed  to  this  im- 
portant object,  and  in  the  space  of  a  very 
few  years,  the  produce  of  nitre  was  more 
than  quadrupled,  and  a  simplicity  and  ex- 
pedition introduced  into  the  refineries  of 
this  salt,  that  seem  to  have  brought  its 
manufacture  nearly  to  perfection. 

In  our  account  of  nitric  acid  we  have 
shown  that  the  component  parts  of  this 
substance  are  azote  and  oxygen  ;  animal 
matters  in  general  contain  a  large  quanti- 
ty of  azote  combined  in  various  propor- 
tions with  hydrogen,  carbon,  and  other 
substances.    When  the  decomposition  of 
animal  matter  by  means  of  the  putrefac- 
tive fermentation  takes  place,  its  elements 
enter  into  new  combinations  with  each 
other,  and  for  the  most  part  assume  the 
gaseous  form.    Now  although  azote,  like 
several  other  bodies,  when  it  has  com- 
pletely acquired  the  state  of  elastic  fluid- 
itv,  is' but  little  disposed  to  combine  with 
oxygen  at  the  usual  atmospheric  temper- 
ature, yet,  when  in  its  nascent  state,  and 
particularly  when  mixed  at  the  same 
time  with  easily  combustible  substances, 
it  unites  with  oxygen  without  much  diffi- 
culty.   Hence  it  is  obvious  how  nitrous 
acid,  or  more  probably  nitrous  vapour,  is 
produced  by  the  contact  of  atmospheric 
air  and  putrid  gas.    But  the  acid  is  pro- 
ducedslowly,  and  in  proportion  as  it  forms 
will  fly  off  together  with  the  other  vola- 
tile ingredients,  except  it  meets 'with  an 
alkaline  base  to  combine  with  into  a  neu- 
tral salt.    It  might  seem,  a  priori,  a  mat- 
ter of  perfect  indifference,  as  far  as  the 
mere  formation  and  detention  of  nitrous 
acid  is  concerned,  whether  one  alkaline 
substance  or  another  was  employed  for 
this  purpose  ;  but  experiment  has  shown, 
as  we  shall  detail  more  at  large  present- 
ly, that  the  proper  fixed  alkalies,  w  hether 
in  a  mild  or  caustic  state,  are  by  no  means 
so  efficacious  as  carbonat  of  lime.  Thus 
it  appears  that  three  conditions  are  requi- 
site for  the  production  of  nitrated  lime 
(from  which  by  the  subsequent  addition 
of  carbonated  potash  common  nitre  is  rea- 
dily obtained)  viz.  animal  matter  in  a  state 
of  decomposition,  atmospheric  air,  or  ra- 


ther the  oxygenous  part  of  it,  and  carbo- 
nated lime. 

The  first  proposal  for  the  construction 
of  artificial  nitre  beds  came  from  Glau- 
ber.   This  able  chemist,  reflecting  on  the 
circumstance,  that  earth  which  had  been 
long  exposed  to  exhalations  from  the 
dung  and  urine  of  sheep  and  other  ani- 
mals, or  in  which  animal  bodies  had  been 
buried,  was  capable  of  affording  nitre  by 
lixiviation,  concluded  that  this  salt  was 
contained  in  animal  matter :  but  finding" 
that  various  animal  fluids,  such  as  urine 
and  blood,  afforded  no  nitre  when  recent, 
he  w  as  induced  to  try  the  effect  of  putre- 
faction on  them  :  for  this  purpose  he  fill- 
ed an  open  vessel  with  blood,  and  exposed 
it  to  spontaneous  decomposition  till  no- 
thing remained  of  it  but  a  loose  earth : 
from  this  by  lixiviation  he  obtained  a  por- 
tion of  nitre;  hence  he  concludes  that  the 
salts  contained  in  recent  animal  matter 
are  in  an  inert,  or,  as  he  calls  it,  a  dead 
state,  till  by  long  exposure  to  the  air  and 
fermentation  they  acquire  from  it  a  vital 
spirit.    From  the  nitrous  efflorescences 
on  the  plaister  of  cellar  walls,  he  inferred 
that  the  saline  base  of  nitre  wras  also  con- 
tained in  certain  earths  ;  and  because  that 
part  of  the  plaister  in  immediate  contact 
with  the  bricks,  and  therefore  excluded 
from  the  air,  afforded  no  nitre  by  lixivia- 
tion, he  drew  the  same  conclusion  as  in 
the  former  case  respecting  the  vivifying 
influence  of  the  air  in  the  formation  of  ni- 
tre-   It  being  a  matter  of  common  noto- 
riety that  earth,  when  long  impregnated 
with  the  lees  of  wine,  became  rich  in  ni- 
tre, this  circumstance,  together  with  other 
collateral  arguments,  induced  him  to  in- 
fer the  presence  of  nitre  in  vegetables  al- 
so.   In  pursuance  of  this  theory,  he  pro- 
poses the  following  plan  for  the  formation 
of  nitre.    Let  a  large  square  wooden  vat 
be  made  open  at  top,  and  with  a  perforat- 
ed false  bottom  placed  a  few  inches  above 
the  real  bottom,  and  between  the  two  bot- 
toms let  a  pipe  with  a  stop  cock  be  in- 
serted so  as  to  discharge  any  liquor  into 
a  shallow  open  reservoir  sunk  into  the 
ground  just  in  the  front  of  the  vat :  on 
the  opposite  side  of  the  reservoir  let  an- 
other vat  similar  to  that  already  described 
be  placed  ;  and,  to  complete  the  apparatus, 
let  a  pump  be  fixed  in  the  reservoir  by 
which  its  contents  may  be  transferred  to 
either  of  the  vats  that  the  workman 
chooses.    Every  thing  being  complete,  let 
the  vats  be  filled  with  horses',  cows',  or 
sheep's  dung  mixed  with  leaves  or  any 
dry  vegetables  :  then  draw  a  weak  alka- 
line ley  from  quicklime  and  woodashes, 
and  pour  it  into  one  of  the  vats  till  it 
stands  a  finger's  breadtli  above  the  other 


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ingredients.  In  about  12  hours  time  turn 
the  cock,  and  let  the  liquor  drain  into  the 
reservoir,  whence  it  is  to  be  pumped 
again  into  the  other  vat,  and  after  12 
hours  more  returned  into  the  reservoir. 
In  the  space  of  a  few  days  the  contents  of 
the  vats  will  heat  and  ferment  strongly  : 
no  further  care  is  required  1  ill  the  decline 
of  the  fermentation,  which  may  be  known 
by  the  cessation  of  the  steam  :  the  mate- 
rials are  then  to  be  again  drenched  with 
the  liquor  in  the  reservoir  for  12  hours, 
and  when  this  is  again  discharged  the  fer- 
mentation will  recommence.  This  me- 
thod being  pursued  lor  ten  or  twelve 
months,  (taking  care  to  keep  the  vats  fill- 
ed with  fresh  portions  of  leaves  and  dung 
as  the  mass  subsides)  both  the  liquor  and 
the  contents  of  the  vats  will  be  found  to 
be  very  rich  in  nitre. 

The  above  method  of  Glauber's  de- 
serves notice  as  the  first  attempt  at  the 
artificial  manufacture  of  nitre,  although 
there  is  little  doubt  that  its  success  is 
greatly  exaggerated,  as  is  but  too  much 
the  custom  of  this  author.  Another  me- 
thod proposed  by  the  same  chemist,  and 
the  success  of  which  is  better  authenti- 
cated, is  the  following.  Construct  a  vault 
of  frame  work  of  any  dimensions,  and 
line  it  to  the  thickness  of  three  or  four 
inches  with  plaister  composed  of  the  fol- 
lowing materials,  viz.  one  part  of  quick- 
lime, one  of  woodashes,  and  two  of  cow's 
or  horse's  dung,  with  a  sufficient  quanti- 
ty of  urine  to  work  it  up  to  a  proper  con- 
sistence. This  plaister  being  carefully 
applied,  is  to  be  dried  by  a  gentle  fire  to 
be  made  under  the  vault,  a  second  coat- 
ing of  the  same  materials  is  then  to  be 
put  on,  and  thus,  by  alternate  drying  and 
plaistering,  the  vault  is  to  be  made  two  or 
three  feet  thick  Being  now  sufficiently 
strong,  the  wooden  framing  may  be  re- 
moved. The  plaister,  in  proportion  as  it 
dries,  is  to  be  restored  to  a  proper  state 
of  moisture  by  the  application  of  urine  ; 
and,  in  the  space  of  a  few  months,  more 
or  less  according  to  the  warmth  of  the  air 
and  other  circumstances,  the  whole  inside 
of  the  vault  will  be  covered  with  nitrous 
efflorescences :  by  degrees  the  plaister 
will  be  impregnated  with  nitre  through 
its  whole  substance,  at  which  time  the 
vault  being  broken  down,  and  its  mate- 
rials being  duly  lixiviated,  a  large  quan- 
tity of  nitre  will  be  obtained.  This  me- 
thod was  adopted  in  many  parts  of  Ger- 
many with  reasonable  success  ;  but,  re-i 
quiring  much  manual  labour,  was  at| 
length  abandoned  for  more  economical! 
processes. 

In  direct  opposition  to  the  instructions 
on  this  subject  by  Glauber,  who  had 


clearly  shown  the  absolute  necessity  of 
the  presence  of  air  to  the  formation  of  ni- 
tre, several  very  large  experiments  were 
made,  chiefly  in  Sweden  and  Germany,  to 
prepare  this  salt  by  filling  large  trenches 
with  animal  and  vegetable  refuse  of  va- 
rious kinds  mixed  with  quicklime  and 
woodashes,  and  duly  watered  with  urine. 
But,  though  all  other  circumstances  were 
tolerably  favourable,  the  exclusion  of  air 
from  the  greater  part  of  the  mass  so  de- 
layed the  production  of  nitre,  that  after 
the  expiration  of  20  years  a  smaller  quan- 
tity of  this  salt  was  thus  obtained  than  is 
yielded  by  the  same  materials  in  two  or 
three  years  when  the  air  is  freely  admit- 
ted to  them.  Attempts  were  made  to  re- 
medy these  defects  by  the  insertion  of 
pipes  and  air  shafts,  but  with  little  success 
compared  to  the  trouble  and  expense  ;  so 
that  at  length,  instructed  by  experience, 
the  Swedes  adopted  that  mode,  which, 
with  a  few  modifications,  they  still  retain, 
and  the  advantages  of  which  are  daily 
more  and  more  apparent.  Upon  a  square 
floor  of  brick  or  stone,  is  laid  a  bed,  a 
few  inches  thick,  composed  of  woodashes, 
lime,  and  mellow  vegetable  earth  mois- 
tened with  urine,  and  the  mother  water 
obtained  in  the  refining  of  nitre  :  upon 
this  is  placed  a  layer  of  straw  or  old 
thatch,  then  another  of  the  composition, 
and  so  on  alternately  till  a  pyramid  8  or 
9  feet  high  is  constructed.  In  order  to 
preserve  these  piles  from  the  rain  and 
snow,  which  would  wash  out  the  salt  as 
fast  as  it  formed,  a  number  of  stout  poles 
are  stuck  in  the  ground  all  round  the 
floor,  the  tops  of  which  are  tied  together, 
and  their  interstices  carefully  closed  with 
intertwisted  twigs,  thus  excluding  the 
rain,  but  admitting  the  air.  These  pyra- 
mids are  watered  from  time  to  time  with 
putrid  urine,  and,  in  about  a  year,  saline  ef- 
florescences begin  to  appear  on  their  sur- 
face :  shortly  after,  the  nitre  thus  gene- 
rated is  swept  off,  and  the  piles  then  yield 
regular  crops  of  this  substance  every  week 
or  ten  days,  except  during  frosty  weather, 
for  about  nine  years.  At  the  expiration 
of  this  period  the  efflorescence  ceases, 
and  the  nitre  yet  remaining  in  the  pile  is 
obtained  by  lixiviation  :  the  insoluble  re- 
sidue is  an  excellent  manure,  and  much 
in  request  for  fl?x  and  hemp.  In  Prussia, 
nitre  is  obtained  from  mud  walls  compos- 
ed of  loamy  earth,  night  soil,  mud  from 
ponds,  stable  litter,  and  any  other  vegeta- 
ble or  animal  substances :  these  being 
mixed  together,  and  tempered  to  the  con- 
sistence of  stiff  mortar  by  urine  and  dung- 
hill drainings,  are  raised  into  walls  four 
tect  high  and  about  two  feet  thick,  and 
topped  with  a  slight  coping  of  thatch  in 


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order  to  shoot  off  the  rain  :  in  process  of 
time,  the  stpaw  and  other  vegetables 
which  the  walls  contain,  decay,  by  which 
it  is  rendered  more  porous,  and  the  air 
gets  admission  more  or  less  to  its  interior 
substance.  Many,  however,  are  the  ob- 
jections to  this  method  of  preparing  ni- 
tre. In  the  first  place,  the  labour  requir- 
ed for  the  construction  of  these  walls  is 
very  considerable:  secondly,  the  clayey 
loam,  which  is  necessary  to  give  the  mass 
a  due  consistence  for  the  formation  of 
walls,  prevents  it  from  being  sufficiently 
p&rous,  even  after  the  straw,  Sec  has  de- 
cayed :  thirdly,  there  is  seldom  a  proper 
quantity  of  calcareous  matter,  so  that 
much  of  the  nitrous  acid  flies  oil' for  want 
of  a  fit  base  to  detain  it :  and  fourthly, 
the  very  imperfect  protection  from  the 
weather  which  these  walls  receive  from 
their  thatch  coping,  subjects  a  considera- 
ble quantity  of  the  salt,  when  formed,  to 
be  washed  out  by  the  rain,  and  thus  lost. 
For  these  reasons,  it  is  seldom  worth 
while  to  lixiviate  this  earth  oftener  than 
once  in  about  six  or  eight  years,  and  even 
then  the  produce  is  very  scanty. 

In  France,  the  njitre-beds  are  composed 
of  nitrous  earth  from  farm-yards,  stables, 
&C.  of  street  sweepings,  of  mild  calca- 
reous earth,  such  as  old  mortar  or  plais- 
ter,  chalk,  tula,  or  the  sweepings  of  roads 
paved  with  limestone;  of  animal  matter, 
such  as  night-soil,  blood,  refuse  from  the 
skinners  and  tanners,  bones  and  other  of- 
fal ;  of  vegetable  matter,  such  as  straw  and 
stable  litter,  leaves,  sawdust,  spent  tan- 
ner's bark,  &c.  These  are  all  mixed  in 
somewhat  casual  proportions,  care  being 
only  taken  that  a  sufficient  quantity  of 
calcareous  matter  is  present;  they  are 
laid  as  lightly  as  possible  in  long  beds  or 
pyramids,  under  covered  roofs,  to  protect 
them  from  the  weather,  and  are  kept  du- 
ly moistened  with  putrid  water  or  urine: 
by  this  management  they  yield  every  other 
year  by  lixiviation  a  considerable  quanti- 
ty of  nitrated  lime,  which,  by  the  addition 
of  woodashes  or  potash  is  converted  into 
true  nitre.  The  circumstance  in  which 
the  French  nitre  beds  differ  principally 
from  those  of  Sweden  and  Germany,  is, 
that  they  scarcely  ever  contain  woodashes, 
the  requisite  portion  of  alkali  being  add- 
tl  in  a  subsequent  part  of  the  manufac- 
ture. 

The  proportion  of  nitre  afforded  by 
these  artificial  beds  it  is  not  easy  to  ascer- 
tain. In  France,  where  the  custom  is  to 
lixiviate  once  in  two  years,  the  produce 
may  be  estimated  at  from  7  to  12  ounces 
of  nitre  from  luOlbs.  of  materials  :  of  this 
about  half  is  nitrat  of  potash,  and  the 
rest  nitrat  of  lime,  requiring  therefore  the 


addition  of  potash  to  convert  it  into  true 
nitre. 

Concerning  the  theory  of  nitrification 
much  has  been  written,  but,  with  the  ex- 
ception of  an  admirable  memoir  by  Mr 
Thouvenel,  to  little  purpose  The  che- 
mists of  the  modern  school,  having  disco- 
vered that  nitric  acid  is  composed  of  ox- 
ygen and  azote,  and  that  animal  matters 
abound  in  condensed  azote,  content  them- 
selves  with  saying,  that  the  azote,  as  it  is 
evolved  by  the  progress  of  putrefaction, 
combines  with  the  oxygenous  part  of  the 
air,  and  thus  forms  nitric  acid,  which  is 
prevented  from  escaping  by  the  lime  and 
other  alkaline  bases  with  which  it  is  in 
contact.  This,  however,  from  the  little 
hitherto  known  on  the  subject,  appears  to 
be  a  very  imperfect  representation  of  the 
matter;  we  shall  therefore  proceed  to  de- 
tail the  principal  results  of  M.  Thouvc- 
nel's  experiments  ;  which,  imperfect  as 
they  are,  throw  more  light  on  this  curious 
and  important  subject  than  any  others 
with  which  we  are  acquainted. 

Several  open  vessels,  containing  each 
three  lbs.  of  pure  and  well  washed  chalk, 
moistened  with  distilled  water,  were,  for 
the  space  of  seven  or  eight  months,  expos 
ed  to  the  putrid  vapours  of  privies,  cel- 
lars, and  prisons  :  being  then  lixiviated, 
they  afforded  from  50  to  90  grs.  of  nitre 
each,  of  which  the  principal  part  was  ni 
trat  of  lime,  but  mixed  in  general  with  a 
little  nitrat  of  potash.  From  other  simi- 
lar  experiments,  M.  Thouvenel  ascertain- 
ed, that  in  close  confined  situations,  where 
there  was  hardly  any  circulation  of  air, 
and  on  the  other  hand,  that  in  places 
where  the  external  air  passed  in  a  free 
current,  the  production  of  nitre  was  by  no 
means  so  copious  as  where  the  putrid 
fumes  remained  for  a  longtime  in  contact 
with  the  chalk,  and  were  only  occasional- 
ly diluted  with  atmospheric  air  In  those 
places  most  favourable  to  the  generation 
of  nitre,  were  exposed,  together  with  the 
vessels  containing-  chalk,  others  with  a 
like  quantity  of  quicklime,  with  magne- 
sia, both  mild  and  caustic,  with  earth  of 
alum,  and  with  the  fixed  alkalies,  both 
mild  and  caustic.  They  were  all  examin- 
ed after  the  expiration  of  8  months  :  the 
saline  contents  of  the  chalk  we  have  just 
mentioned ;  the  quicklime,  the  caustic, 
and  mild  magnesia,  afforded  from  6  to  7 
grs.  of  earthy  nitrat  mixed  with  a  little 
ammoniacal  nitrat ;  the  earth  of  alum 
yielded  a  still  smaller  proportion  of  ni- 
trat, and  the  fixed  alkalies  none  at  all. 
The  results  of  these  experiments  being 
ascertained,  another  series  was  underta- 
ken and  conducted  in  the  following  man- 
ner.   An  earthen  cucurbit  was  fitted  to  a 


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very  large  receiver  of  the  same  materials 
pierced  with  a  few  small  holes  so  as  to  al- 
low of  a  partial  communication  between 
its  contents  and  the  outer  air  :  in  the  cu- 
curbit was  put  some  putrid  blood,  and  in 
the  receiver  were  placed  open  vessels  con- 
taining a  few  ounces  of  lime,  magnesia, 
earth  of  alum,  and  the  fixed  alkalies, 
both  mild  and  calcined:  21  other  re- 
ceivers furnished  in  the  same  manner 
were  connected  with  cucurbits  charged 
with  various  putrescent  mixtures.  The 
gas,  as  it  was  disengaged  from  the  mate- 
rials in  the  cucurbit,  passed  into  the  re- 
ceiver, mixing  with  the  atmospherical  air, 
and  surrounding  the  enclosed  earth  and 
alkalies.  After  this  process  had  been  con- 
tinued for  a  year  or  more,  the  contents  of 
the  receivers  were  examined  ;  in  all  of 
them  the  chalk  was  found  to  contain  ni- 
trat  of  lime,  but  varying  in  proportion 
from  one  to  5  grains  per  oz.  The  quick- 
lime, the  magnesia,  and  earth  of  alum,  in 
most  of  the  experiments,  had  acquired  no 
nitric  acid,  but  in  some  a  little  earthy  ni- 
trat  was  formed.  The  fixed  alkalies,  as 
in  the  former  experiments,  had  acquired 
no  nitric  acid  whatever.  It  was  further 
observed,  that  although  the  chalk  in  most 
of  the  experiments  showed  signs  of  nitri- 
fication  in  about  a  month's  time,  and  pro- 
ceeded rapidly  for  the  first  three  months, 
vet  after  this  period  the  progress  was  ve- 
ry slow,  no  doubt,  because  the  oxygen  of 
the  atmospheric  air  originally  contained  in 
the  receivers  having  been  consumed,  the 
gradual  pouring  in  of  putrid  gas  from  the 
cucurbit  almost  entirely  preventing  the 
external  air  from  entering  through  the 
small  holes  that  had  been  drilled  for  this 
purpose. 

It  appearing  from  the  above  experi- 
ments, that  the  fixed  alkalies  and  the  al- 
kaline earths  themselves  when  caustic  are 
very  little  capable  of  absorbing  nitric  acid 
from  a  mixture  of  putrid  gas  and  atmos- 
pheric air,  M.  Thouvenel  w  as  induced  to 
try  whether  this  was  owing  to  any  change 
produced  on  the  putrid  gas  by  these  bo- 
dies.   For  this  purpose,  having  charged  a 
retort  with  putrefying  materials,  lie  con- 
nected with  it  three  receivers  in  the  man- 
ner of  Woulfe  bottles,  the  last  of  which 
terminated  in  a  tube  communicating  with 
a  pneumatic  apparatus.    Four  different 
sets  of  this  apparatus  were  employed  at  j 
the  same  time.    In  the  first  of  these,  the  j 
two  receivers  nearest  the  retort  were  j 
charged  with  four  ounces  of  chalk  diffus-  i 
ed  in  distilled  water,  while  the  third  re- 
ceiver  contained  a  solution  of  caustic  pot- ; 
ash.    In  the  second  set,  the  two  first  re-  j 
ceivers  contained  distilled  water,  and  the  , 
last  was  charged  with  tiie  washed  chalk,  j 


in  the  third  set,  the  two  first  receivers 
contained  limewater ;  and  in  the  fourth 
set,  a  solution  of  caustic  potash,  the  third 
receiver  in  both  cases  holding  the  chalk. 
They  were  all  equally  exposed  to  the  same 
temperature,  namely,  from  74°  to  80° 
Fahr.  for  six  months,  and  the  changes 
which  their  contents  had  undergone  were 
then  examined. 

The  chalk  in  the  first  apparatus  af- 
forded 26  grs.  of  nitrat  of  lime  mixed  with 
a  little  nitrat  of  ammonia  ;  the  potash  in 
the  third  receiver  had  become  saturated 
with  carbonic  acid,  and  had  partly  crys- 
tallised on  the  side  of  the  receiver,  but 
contained  no  nitre. 

In  the  second  apparatus  the  water  of 
the  two  first  receivers  had  acquired  a  very 
putrid  smell  from  the  gas  which  had  pass- 
ed through  it,  and  contained  a  little  am- 
monia, but  afforded  no  nitrous  salt  on 
evaporation  :  the  chalk  in  the  third  re- 
ceiver afforded  by  lixivation  no  more  than 
four  grains  of  nitrated  lime. 

In  the  third  apparatus  the  lime  water 
had  deposited  its  earth  in  the  state  of 
carbonat,  and  the  supernatant  fluid  had  a 
strong  odour  resembling  ammonia  and 
putrid  garlic  :  by  evaporation  it  yielded 
five  or  six  grains  of  nitrated  ammonia. 
The  chalk  in  the  third  receiver  gave  only 
a  slight  trace  of  nitrat  of  lime. 

In  the  fourth  apparatus  the  potash  was 
crystallized  but  contained  no  nitre  :  with 
sulphuric  acid  it  effervesced  strongly, 
giving  out  a  very  pungent  and  highly  fetid 
gas  :  the  chalk  in  the  third  receiver  gave 
no  indications  whatever  of  the  presence  of 
any  nitrous  salt. 

The  gas  remaining  in  the  receivers  and 
collected  in  the  pneumatic  apparatus  was, 
in  all  the  four  experiments,  found  to  be 
slightly  infiammable,  although  when  ris- 
ing from  the  putrefying  materials  it  ex- 
tinguished a  taper  immersed  in  it.  This 
putrid  inflammable  gas  was  incapable  by 
itself  of  nitrifying  chalk,  but,  when  mixed 
with  washed"  atmospheric  air,  carbonic 
acid  soon  made  its  appearance,  and  then 
the  gas  became  incapable  of  impregnating 
chalk  with  nitrous  acid  as  at  first. 

The  above  experiments  were  under- 
taken when  pneumatic  chemistry  had  as 
yet  made  but  little  progress,  and  there- 
fore the  deductions  from  them  are  by  no 
means  equivalent  to  the  labour  and  time 
employed  in  carrying  them  on  :  it  appears 
however,  that  we  may  legitimately  draw 
the  following  conclusions.  In  the  first 
place,  the  formation  of  nitric  acid  from 
animal  matter  in  putrefaction,  is  not  owing 
to  atmospheric  air,  being  presented  to  the 
azote  when  in  a  nascent  state  ;  for  this 
change  takes  place  after  the  azote  and 


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other  gazefiable  substances,  have  actually  I 
assumed  the  elastic  form.  Secondly,  the 
elements  of  the  putrid  gas,  are  carbonic 
acid,  azote,  hydrogen  and  carbon,  not  mix- 
ed but  combined  together,  though,  weak- 
ly :  this  combination  is  in  part  destroyed 
by  mere  washing  in  water,  but  more  com- 
pletely by  the  action  of  those  alkaline  ba  - 
•ses,  that  are  not  completely  saturated 
with  carbonic  acid ;  when  the  carbonie 
acid  is  abstracted,  the  further  decompo- 
sition of  this  gas  by  atmospheric  air,  tends 
more  to  the  production  of  ammonia  and 
carbonic  acid,  than  of  nitric  acid.  Wash- 
ed chalk  after  being  thus  nitrified  often 
contains  a  little  nitrat  of  potash,  as  well 
as  nitrated  lime  :  it  does  not  however, 
hence  necessarily  follow,  that  potash  is 
also  a  product  of  putrefaction  ;  for  it  may 
possibly  pre-exist  in  the  chalk,  in  a  state 
insoluble  in  water,  as  it  does  in  leucite,  in 
the  alum  ore  of  La  Tolfa,  and  other  mi- 
nerals. The  important  practical  conclu- 
sion to  be  deduced  from  these  experi- 
ments, is,  that  the  only  alkaline  substance 
to  be  admitted  in  the  composition  of  nitre 
beds  is  mild  calcareous  earth. 

Chalk  however  is  not  only  capable  of 
being  nitrified  by  exposure  to  the  com- 
bined action  of  atmospheric  air  and  putrid 
gas,  but  also  by  means  of  the  atmosphe- 
ric air  alone.  On  this  subject  there  are 
some  experiments  by  Lavoisier  andClouet, 
much  to  the  purpose.  The  village  of 
Roche  Guyon  on  the  Seine,  is  situated  on 
a  ridge  of  chalk,  which,  having  the  cha- 
racter of  nitrifying  spontaneously  by  ex- 
posure to  the  air,  was  on  this  account 
visited,  and  particularly  examined  by  the 
able  chemists  just  mentioned.  In  order 
to  ascertain  whether  this  chalk  before  the 
action  of  the  air  contained  any  nitrous  salt, 
selection  was  made  of  a  part  of  the  rock 
which  had  recently  been  laid  bare,  by  the 
falling  down  of  a  large  mass.  In  this 
newly-exposed  face  of  rock,  a  gallery  had 
been  driven,  of  which  the  further  extre- 
mity had  been  excavated  only  two  or  three 
days  before.  In  order  to  render  the  ex- 
periment as  unexceptionable  as  possible, 
about  a  foot  more  of  chalk  was  removed 
from  the  extremity  of  the  gallery  ;  after 
which  a  specimen  of  the  weight  of  12^  lbs. 
was  dug  out,  and  subjected  to  lixiviation  : 
by  evaporation  of  the  fluid,  there  were 
deposited  four  grains  of  miniated  soda  ; 
and  the  small  residue  of  mother  water, 
afforded,  by  the  addition  of  carbonated 
potash,  53  grains  more  of  salt,  which  ap- 
peared to  be  muriat  of  potash,  with  per- 
haps a  slight  admixture  of  nitre  :  for  al- 
though it  did  not  detonate  in  the  smallest 
degree  with  charcoal,  yet  by  sulphuric 
acid  it  gave  out  acid  fumes,  in  which  the 


odour  of  nitro -muriatic  acid  was  just  per* 
ceptible. 

It  appears,  that  chalk  composing  many 
rocks,  though  perhaps  not  absolutely  and 
entirely  destitute  of  nitric  acid,  even  at 
their  centre,  is  much  more  abundant  in 
this  substance,  in  proportion  as  it  is  situ- 
ated near  their  surface  ;  and  that  the  per- 
fect nitre  or  nitrat  of  potash,  is  only  found 
near  the  surface  of  the  chalk  :  a  circum- 
stance which  seems  to  shew,  that  both  the 
acid  and  alkali,  have  been  either  deposited 
from  the  air,  or  formed  by  the  contact  of 
this  latter  with  the  chalk.  In  confirma- 
tion of  this  deduction  may  be  mentioned., 
an  experiment  by  the  Due  de  la  Roche- 
foucault,  who  lixiviated  a  considerable 
quantity  of  chalk,  so  as  to  dissolve  out  its 
saline  contents,  and  then  exposed  it  to  the 
action  of  the  air  for  fourteen  months,  dur- 
ing which  period,  it  had  acquired  not  only 
nitric  acid  but  potash,  since  the  liquor  of 
the  second  lixiviation  deposited  by  eva- 
poration a  little  nitre,  and  afterwards  a 
considerable  quantity  more  on  the  addi- 
tion of  potash.  These  facts  having  never 
been  called  in  question,  the  next  inquiry 
that  occurs,  is  whether  the  atmosphere 
furnishes  the  entire  nitric  acid,  or  only 
one  of  the  constituent  parts  of  it  ?  That 
this  latter  is  the  case,  might  be  inferred 
from  the  frequent  occurrence  of  organic 
remains,  and  impressions  in  chalk,  whence 
this  mineral  may  be  supposed  to  be  by  no 
means  destitute  of  animal  matter.  Against 
this  however,  there  may  be  alleged  a  di- 
rect experiment  by  M.  Thouvenel,  who, 
on  exposing  some  washed  chalk,  for  six 
or  seven  months  to  a  portion  of  atmos- 
pheric air,  confined  in  a  large  receiver, 
and  previously  well  washed  in  distilled 
water,  found  that  not  an  atom  of  nitrat 
of  lime  was  generated  :  while  in  a  similar 
experiment,  in  which  washed  chalk  was 
exposed  to  unvtasked  air,  a  very  sensible 
quantity  of  nitrated  lime  was  produced. 
Now  the  washing  could  not  separate  the 
azot  or  oxygen,  though  it  might  and  no 
doubt  would  take  away  any  nitric  acid 
ready  formed,  or  any  nitrous  salt  that 
might  be  contained  in  the  atmosphere.  It 
is  observed  of  these  chalk  rocks,  that 
those  parts  that  are  adjacent  to  inhabited 
buildings,  yield  a  greater  proportion  of 
nitrat  of  potash  than  those  which  are  at  a 
distance  from  houses ;  a  circumstance 
that  seems  to  point  out  a  probable  source 
of  the  alkali,  without  supposing  it  to  be 
generated,  either  in  the  air  or  chalk.  It 
is  well  known,  that  the  common  fuel  in 
France  is  wood,  therefore  the  air  in  the 
vicinity  of  houses,  must  be  more  or  less 
impregnated  with  pyroligneous  acid  con- 
tained in  the  wood  smoke ;  but  the  acid 


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vapour  that  flies  off  in  the  common  me- 
thod of  preparing  charcoal  (and  which  is 
no  other  than  pyroligneous  acid)  when 
collected  in  a  proper  apparatus,  condenses 
into  a  sour  liquid,  from  which,  by  g  ntle 
evaporation,  a  black  residue  is  procured, 
that  yields  by  incineration  a  large  propor- 
tion of  potash. 

It  only  remains  to  give  an  account  of 
the  extraction  of  nitre,  from  the  earths 
in  which  it  is  contained,  and  of  the  purifi- 
cation of  this  salt. 

The  first  thing  is  to  assay  the  earth. 
This  is  done  by  lixiviating  a  few  pounds 
of  it,  and  adding  to  the  liquor  thus  ob- 
tained, as  much  of  a  solution  of  common 
potash  of  a  known  strength,  as  is  suffici- 
ent to  decompose  all  the  earthy  salts. 
From  this  assay  the  quantity  of  alkali  re- 
quired is  easily  calculated. 

The  next  process  is  the  lixiviation; 
which  is  performed  in  the  following  man- 
ner. Several  cart-loads  of  nitrous  earth 
are  mixed  as  accurately  as  possible,  with 
the  requisite  quantity  of  alkali,  either  in 
the  form  of  wood-ashes  or  pulverised  pot- 
ash. Several  large  casks  with  perforated 
false  bottoms,  are  then  filled  with  the  pre- 
pared earth,  laid  on  very  lightly  ;  after 
which  as  much  river  water  is  poured  in,  as 
the  vessels  will  hold.  In  two  or  three 
hours  time,  the  cock  at  the  bottom  of  each 
cask  is  turned,  and  the  liquor  is  allowed 
to  drain  out,  during  the  remainder  of  the 
day.  The  casks  of  a  second  series  charg- 
ed with  earth  as  before,  are  new  filled  up 
with  the  first  lixivium,  and  after  standing 
for  a  few  hours,  the  liquor,  thus  concen- 
trated, is  drawn  off  in  the  manner  just 
described.  By  a  similar  process  on  ihe 
third  day,  a  lixivium  thrice  as  strong  as 
the  first  is  obtained,  which  is  now  suffici- 
ently concentrated,  to  be  boiied  down. 
The  contents  of  each  series  of  casks,  are 
lixiviated  twice  more,  and  the  weak  solu- 
tions thus  obtained,  are  employed  instead 
of  water,  in  the  first  and  second  lixiviations 
of  fresh  parcels  of  earth. 

The  boiling  down  and  evaporation  next 
succeeds.  The  lixivium,  containing  nitrat 
of  potash,  the  muriats  of  potash  and  soda, 
with  probably  a  few  other  salts,  and  va- 
rious earthy  and  other  impurities,  is  put 
into  a  large  boiler  like  a  salt  pan,  and 
heated  nearly  to  ebullition  ;  it  is  then  cla- 
rified by  the  addition  of  bullock's  blood, 
or  a  solution  of  glue,  the  impurities,  as 
they  appear  on  the  surface,  being  care- 
fully skimmed  off:  when  no  more  froth 
rises  of  itself,  a  little  lime-water  is  added, 
which  coagulates  the  remainder  of  the 
blood  and' glue,  and  thus  completes  the 
clarification.  It  is  now  boiled  for  several 
hours,  and  the  muriats  of  potash  and  soda 


as  they  deposit,  are  withdrawn  by  a  per- 
forated ladle.  When  the  liquor  is  so  con- 
centrated, that  a  few  drops  crystallize 
readily  on  being  dropped  on  a  cold  iron, 
it  is  laded  out  into  a  vat,  where  it  remains 
half  an  hour  to  deposit  the  common  salt 
and  impurities,  still  floating  in  it :  hence 
it  is  transferred  to  large  wooden  or  me- 
tallic crystallizing  basons,  where  it  re- 
mains close  covered  up,  during  from  three 
to  six  days,  according  to  the  temperature 
of  the  air ;  at  the  expiration  of  this  period, 
the  fluid  mother  water  is  poured  out  and 
returned  to  the  nitre  bed,  and  the  salt 
deposited  in  a  confused  crystalline  mass 
of  an  opake  dirty  white,  is  broken  to  pieces 
and  set  to  drain,  after  which  it  is  brought 
to  market,  or  delivered  into  the  govern- 
ment stores,  as  rough  nitre  or  nitre  of  the 
first  boiling. 

Jn  order  to  refine  the  rough  nitre,  the 
ancient  practice  was  to  subject  it  to  two 
more  successive  boilings  and  crystalliza- 
tions ;  by  this  method,  however,  a  very 
considerable  proportion  of  the  nitre  was 
left  in  the  mother  waters,  no  inconsidera- 
ble share  was  volatilized,  by  the  heat  re- 
quired for  evaporating  the  solution,  when 
it  had  nearly  acquired  the  due  degree  of 
concentration,  and  besides  a  great  ex- 
pense both  of  time  and  fuel  was  incurred. 
The  modern  method  of  refining  this  salt 
was  invented  in  France,  a  few  years  ago, 
and  is  now  considered  as  brought  nearly 
to  perfection.    It  is  thus  effected: 

The  rough  nitre  is  broken  to  small 
fragments  by  wooden  mallets,  and  is  then 
put  into  a  wooden  tub,  with  20  per  cent. 
by  weight  of  cold  water ;  in  this  state  it 
remains  for  six  or  seven  hours,  being  oc- 
casionally well  stirred  up,  that  the  water 
may  have  free  access  to  every  part.  The 
water  is  now  let  out  by  a  hole  at  the  bot- 
tom of  the  vessel,  and  carries  witli  it  in 
solution  all  the  deliquescent  salts,  and  the 
greatest  part  of  the  muriats  of  soda  and 
potash,  together  with  some  nitre.  When 
the  whole  of  the  liquor  is  drawn  off  10 
per  cent,  more  of  water  i6  added,  and  well 
mixed  with  the  nitre  for  an  hour's  time, 
when  it  is  discharged  in  the  same  manner 
as  the  first.  Lastly,  5 per  cent,  of  water  is 
poured  in  and  run  off  again,  almost  im- 
mediately after.  The  nitre  thus  washed, 
after  being  well  drained,  is  put  into  a  boiler 
with  half  its  weight  of  water,  and  boiled 
till  a  peilicle  forms  on  its  surface ;  the 
liquor  is  then  discharged  into  a  large 
leaden  cooler,  and  stirred  about  with 
rakes,  till  it  is  quite  cold  ;  by  which  mani- 
pulation, the  salt  is  deposited  in  small 
crystalline  needles.  It  is  now  taken  out 
of  the  liquor,  with  a  perforated  ladle 
and  well  drained  :  after  which  it  is  wash- 


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e,d  with  5  per  cent,  of  cold  water,  and  again 
drained  :  being  then  spre  ad  out  on  a  large 
table  it  dries  in  a  few  hours,  and  is  lastly 
heated  over  a  fire  in  large  basons  for  two 
or  three  hours,  at  a  temperature  not  ex- 
ceeding 120°  Fahr  taking  care  to  stir  it 
all  the  while;  by  this  treatment  it  is  per- 
fectly purified,  and  brought  to  the  con- 
sistence of  fine  sand,  and  is  now  ready  to 
be  manufactured  into  gunpowder. 

In  addition  to  the  remarks  before  made 
we  have  been  induced  to  give  the  follow- 
ing "  Instructions  respecting  the  Purifica- 
tion of  Saltpetre,  drawn  up  by  order  of 
the  Committee  of  Public  Safety  of  Paris  ; 
by  whose  order  also  ;  his  Process  is  adopt- 
ed in  all  the  Laboratories  of  France," 
from  the  Repertory  of  Arts,  vol.  viii,  p 
199.  Translated  from  the  Annates  de  Chi- 
onie. 

The  crude  saltpetre  is  first  to  be  bruised 
with  wooden  beaters,  that  the  water,  with 
which  it  is  afterwards  to  be  washed,  may- 
more  easily  act  upon  every  part  of  it. 

The  saltpetre,  thus  bruised,  is  then  to 
be  carried  to  proper  tubs  or  vats,  in  each 
of  which  five  or  six  hundred  pounds  may- 
be put. 

Water  is  to  be  poured  upon  the  salt- 
petre, in  the  proportion  of  twenty  parts  to 
a  hundred,  and  the  mixture  is  to  be  well 
stirred. 

It  is  then  to  be  left  to  macerate  or  soak, 
till  the  liquor  will  dissolve  no  more.  Six 
or  seven  hours  are  sufficient  for  this  first 
operation  ;  the  liquor  then  indicates  from 
twenty -five  to  thirty-five  degrees,  by  the 
peseMqufittr. 

This  first  washing  is  then  to  be  drain- 
ed off,  and  fresh  water,  in  the  proportion 
often  parts  to  a  hundred,  is  to  be  poured 
on  the  saltpetre. 

The  mixture  is  to  be  stirred,  and  left 
to  soak  for  the  space  of  an  hour;  the 
water  is  then  to  be  again  drained  off. 

Fresh  water  is  to  be  once  more  poured 
on  the  saltpetre,  in  the  proportion  of  five 
parts  to  a  hundred;  which  water,  after 
stirring,  is  to  be  immediately  drained  off. 

This  drained  saltpetre  is  then  to  be  put 
into  a  cauldron,  containing  fifty  parts  of 
boiling  water  to  a  hundred.  When  the 
saltpetre  is  dissolved,  the  solution  ought 
to  indicate  from  sixty-six  to  sixty-eight 
degrees,  by  the  pese-iiqueiir. 

The  solution  is  then  to  be  carried  to  a 
crystallizing  vessel,  in  which,  by  cooling, 
about  two-thirds  of  the  saltpetre  made  use 
of  will  be  precipitated:  the  precipitation 
begins  in  about  half  an  hour,  and  finishes 
from  four  to  six  hours  afterwards  But, 
as  it  is  of  importance  that  the  saltpetre 
should  be  obtained  in  the  form  of  thin 

VOL.  II. 


needles,  because  in  this  form  it  is  more 
easily  dried,  it  is  necessary  that  the  liquor 
in  the  crystallizing  vessel  should  be  stir- 
red the  Whole  time  the  precipitation  is 
forming.  The  Stirling  is  performed  by 
means  of  a  kind  of  rake,  which  gives  a 
slight  motion  to  the  mass  of  liquor,  and 
causes  the  crystals  to  be  precipitated  in 
the  form  of  thin  needles. 

As  the  precipitation  takes  place,  the 
crystals  are  to  be  brought  to  the  border 
of  the  crystallizing  vessel;  to  be  taken  up 
with  a  skimmer,  and  put  to  drain  in  bas- 
kets placed,  for  that  purpose,  upon  frames, 
in  such  a  manner  that  the  water  which 
runs  from  the  crystals,  may  fall  again  into 
the  crystallizing  vessel,  or  it  may  be  re- 
ceived in  basons  placed  under  the  baskets. 

The  saltpetre  is  then  to  be  thrown  into 
wooden  boxes,  formed  like  the  hopper  of 
a  mill,  and  having  a  double  bottom.  The 
upper  bottom  is  supported,  by  means  of 
pieces  of  wood,  about  two  inches  above 
the  lower  one,  and  is  pierced  full  of  small 
holes;  through  these  holes  the  liquor 
drains  off,  and  finally  passes,  through  a 
hole  made  in  the  lower  bottom,  into  a  re- 
servoir  beneath.  In  these  boxes  the  salt- 
petre is  to  be  washed,  with  five  parts  of 
water  to  a  hundred;  this  water  may  be 
used  for  dissolving  the  saltpetre  in  future 
operations. 

The  saltpetre,  after  being  well  drained, 
and  exposed  to  the  air  for  some  hours, 
upon  proper  tables  for  drying  it,  may  be 
afterwards  made  use  of  for  preparing  gun- 
powder. 

But,  when  it  is  intended  to  make  use  of 
the  saltpetre  for  making  gunpowder,  ac- 
cording to  the  process  followed  since  the 
revolution,  it  must  be  much  more  highly 
dried.  This  may  be  accomplished  by 
placing  it  in  a  stove;  or,  what  is"  more 
simple,  by  heating  it  in  a  shallow  caul- 
dron. For  this  purpose,  a  layer,  five  or 
six  inches  in  thickness,  is  to  be  put  in  the 
cauldron,  which  is  to  be  heated  to  40  or 
50  degrees  of  Reaumur's  thermometer. 

The  saltpetre  is  to  be  stirred  for  two 
or  three  hours,  and  to  be  so  much  dried, 
that,  when  strongly  pressed  in  the  hand, 
it  does  not  acquire  any  consistence,  nor 
retain  any  form,  but  appears  like  fine  dry 
sand. 

This  degree  of  dryness  is  not  necessa- 
ry, when  gunpowder  is  to  be  made  by 
beating  with  pestles. 

It  is  then  evident  that,  according  to  the 
method  of  purification  we  have  prescribed, 
there  are  two  kinds  of  liquor  to  consider; 
first,  the  water  from  the  various  washings 
of  the  crude  saltpetre  ;  secondly,  the  wa- 
ter from  the  crystallizing  vessels- 
U 


SIT 


The  washing  of  the  crude  saltpetre  is 
repeated  three  times,  as  we  have  already 
mentioned. 

In  these  three  operations,  thirty-five 
parts  of  water  to  a  hundred  of  saltpetre, 
according  to  the  quantity  of  it  meant  to 
be  purified,  are  employed  in  washing. 

These  washings  are  founded  upon  the 
principle  which  establishes,  that  cold  wa- 
ter dissolves  the  muriat  of  soda,  (sea  salt) 
the  earthy  nitrates  and  muriates,  and  the 
colouring  principle,  while  it  scarcely  acts 
upon  the  nitrate:  of  potash,  (pure  salt- 
petre) 

The  water  from  these  three  washings, 
therefore,  contains  the  muriate  of  soda, 
the  earthy  salts,  the  colouring  principle, 
and  a  small  portion  of  nitrate  of  potash, 
the  quantity  of  which  is  in  proportion  to 
the  muriate  of  soda,  which  determines  its 
solution. 

The  water  from  the  crystallizing"  ves- 
sels contains  that  portion  of  muriate  of 
soda,  and  of  earthy  salts,  which  were  not 
dissolved  by  the  washings,  also  a  more 
considerable  quantity  of  nitrate  of  potash 
than  was  contained  in  the  water  of  the 
Washings. 

The  water  which  is  employed  at  the 
end  of  the  process,  to  wash  and  whiten 
the  crystals  placed  in  the  wooden  box, 
holds  in  solution  only  a  small  quantity  of 
nitrate  of  potash. 

These  liquors,  therefore,  are  of  a  very 
different  nature. 

The  waters  proceeding  from  the  wash- 
ings, may  properly  be  called  mother-wa- 
ters ;  they  ought  to  be  collected  together 
in  basons,  and  treated  with  potash,  ac- 
cording to  the  usual  method.  At  the  re- 
finery called  de  F  Unite,  they  are  evapo- 
rated to  sixty-six  degrees,  and  the  mu- 
riate of  soda  is  taken  away  as  fast  as  it  is 
deposited;  this  solution  is  saturated  with 
potash,  in  the  proportion  of  two  or  three 
to  the  hundred  ;  it  is  then  suffered  to  set- 
tle, and  the  liquor  is  afterwards  decanted 
into  crystallizing  vessels,  in  which  are 
thrown  twenty  parts  of  water  to  a  hun- 
dred, that  all  the  muriate  of  soda  may  be 
kept  in  solution. 

The  liquor  which  remains  above  the 
crystals,  produced  by  this  treatment  of 
the  mother-waters,  may  be  mixed  with 
the  water  of  the  first  crystallization.  The 
muriate  of  soda  may  be  separated  from 
this  liquor  by  simple  evaporation  ;  and  the 
nitrate  of  potash,,  which  it  holds  in  solu- 
tion, may  be  obtained  from  it  by  cooling-. 

The  small  quantity  of  water  made  use 
of  to  whiten  the  refined  saltpetre,  contains 
only  nitrate  of  potash  ;  it  may,  therefore, 
be  made  use  of  for  dissolving  the  saltpe- 
tre in  the  cauldrons. 


From  the  foregoing  account  it  is  evi- 
dent, that  a  laboratory  destined  for  the 
purification  of  saltpetre,  according  to  the 
process  here  described,  ought  to  be  pro- 
vided with  the  following  articles. 

1.  Wooden  beaters  for  bruising  the 
crude  saltpetre. 

2.  Tubs  or  vats,  in  which  the  saltpetre 
is  to  be  washed. 

3.  A  cauldron,  in  which  the  solution  is 
to  be  made. 

4.  A  crystallizing  vessel,  of  copper,  or 
of  lead,  in  which  the  liquor  is  to  be  cool- 
ed, and  the  saltpetre  crystallized. 

5.  Baskets  for  draining  the  crystals. 

6.  A  wooden  box,  in  which  the  crystals 
are  to  be  more  thoroughly  drained,  and 
the  saltpetre  washed  for  the  last  time. 

7.  Scales  for  weighing  the  saltpetre. 

8.  Thermometers  and  ptse -liqueurs,  to 
determine  the  degree  of  heat,  and  that  of 
consistence. 

9.  Rakes  to  stir  the  liquor  in  the  crys- 
tallizing vessel. 

10.  Skimmers  to  take  off  the  crystals, 
and  put  them  into  the  baskets. 

11.  Syphons,  or  cranes,  to  empty  the 
cauldrons. 

The  number  of  these  implements,  and 
their  dimensions,  must  necessarily  vary., 
according  to  the  quantity  of  saltpetre  pro- 
posed to  be  purified. 

Supposing  it  is  wished  to  purify  ten 
thousand  pounds  of  crude  saltpetre  per 
day  ;  the  number  of  men  and  utensils,  ne- 
cessary for  that  purpose,  may  be  deter- 
mined according  to  the  following  calcu- 
lation. 

On  Weighing  and  Bruising  the  Crude  Salt- 
petre. 

A  piece  of  ground  must  be  set  apart, 
as  near  the  magazine  as  possible,  for  the 
purpose  of  beating  or  bruising  the  crude 
saltpetre. 

This  ground  must  be  covered  with  broad 
smooth  stones,  or  with  very  thick  boards. 

For  brusing  the  saltpetre,  wooden  beat- 
ers may  be  made  use  of,  similar  to  those 
which  are  used  for  beating  mortar. 

Two  men  are  sufficient  for  carrying  the 
saltpetre  to  the  magazine,  for  weighing  it, 
and  bruising  it. 

On  Washing  the  Saltpetre. 
As  the  three  washings  take  up  the 
space  of  two  days  [This  neither  agrees 
with  the  time  stated  in  the  beginning  of 
the  paper  as  necessary  for  the  three  wash- 
ings, nor  with  what  has  just  now  been 
said,  that  ten  thousand  pounds  may  be 
thus  refined  per  day.  We  notice  this,  lest 
our  readers  should  think  our  translation 
erroneous,]  and  as  each  of  the  tubs  or 


NIT 


NIT 


vats  will  contain  only  five  or  six  hundred 
pounds  of  saltpetre,  twenty  of  them  will 
be  necessary  for  the  purification  of  ten 
thousand  pounds. 

These  tubs  are  to  be  two  feet  and  a 
half  in  height,  and  the  same  in  breadth. 

They  must  be  constructed  with  the 
greatest  care,  that  the  water  used  in  wash- 
ing  the  saltpetre  may  not  escape  through 
them. 

They  should  be  firmly  fixed  upon  a 
plane,  slightly  inclined,  of  such  a  nature 
that  the  water  from  the  saltpetre  cannot 
soak  into  it.  This  plane  should  be  termi- 
nated by  a  gutter,  to  receive  the  water 
from  the  saltpetre,  and  to  conduct  it  into 
a  reservoir  placed  at  the  end  of  the  row 
of  tubs. 

These  twenty  tubs  may  be  disposed  in 
two  parallel  lines.  The  planes  upon 
which  they  are  fixed  may  be  inclined  to- 
wards  each  other ;  so  that  their  union 
may  form  the  gutter  or  channel  w  hich  is 
to  conduct  into  the  common  reservoir  the 
water  that  runs  off*. 

These  tubs  are  to  have  an  aperture  at 
the  distance  of  two  fingers'  breadth  from 
the  bottom;  which  aperture  (besides  the 
stopper  which  closes  it)  must  have  a 
grated  or  perforated  cover. 

Four  men  may  be  allotted  to  the  wash- 
ing of  the  saltpetre :  they  should  also  have 
the  charge  of  carrying  the  saltpetre  from 
the  magazine  to  the  tubs,  and  from  the 
tubs  to  the  cauldron. 

It  is  hardly  necessary  to  mention,  that 
the  tubs  should  be  separate  from  each 
other,  and  disposed  in  such  a  manner  that 
they  may  be  easily  served. 

0:i  the  Cauldron. 

A  conical  cauldron,  five  feet  broad,  and 
four  feet  deep,  will  supply  three  opera- 
tions in  the  day ;  and  consequently  will 
suffice  for  the  purification  of  fifteen  thou- 
sand pounds  of  saltpetre. 

One  man  is  sufficient  for  the  service  of 
the  cauldron. 

On  the  Vessel  for  Crystallization. 

The  crystallizing  vessel  should  be  made 
of  lead,  or  of  copper,  and  should  be  placed 
as  near  the  cauldron  as  possible. 

It  should  be  fifteen  inches  in  depth,  ten 
feet  in  length,  and  eight  in  breadth. 

It  should  be  fixed  upon  very  solid 
ground,  in  such  a  manner  that  every  point 
of  the  bottom  may  be  supported.  The 
stone  or  brick  work  on  which  it  is  placed, 
should  be  raised  twelve  inches  above  the 
ground  ;  by  this  means,  the  brink  of  the 
crystallizing  vessel  will  be  twenty-seven 
inches  above  the  ground,  which  will  ren- 


der the  service  of  it  more  easy  and  con- 
venient. 

It  appeared  to  us  advantageous,  to  give 
the  bottom  of  the  crystallizing  vessel  an 
inclination  of  four  inches  (in  the  longitu- 
dinal direction  only)  from  the  sides  to  the 
centre. 

The  solutions  from  the  cauldron  may 
be  emptied  several  times  successively  into 
the  vessels,  after  having  taken  away  the 
deposition  of  crystals  arising  from  each 
solution. 

Four  men  seem  necessary  for  the  ser- 
vice of  the  crystallizing  vessel.  They  must 
keep  the  liquor  constantly  stirred,  by 
moving  the  rakes  therein;  they  must  con- 
tinually bring  towards  the  edges  of  the 
vessel  the  crystals  which  are  formed  ;  they 
must  take  them  out  "-with  a  skimmer,  and 
carry  them  to  the  baskets  which  are  to 
receive  them,  and  in  which  they  are  to 
drain. 

The  same  men  may  put  the  saltpetre 
into  the  wooden  boxes  in  which  the  drain- 
ing is  completed,  and  may  afterwards 
carry  it  into  the  magazine  for  purified 
saltpetre. 

For  want  of  a  large  vessel  for  crystal- 
lization, a  shallow  cauldron  may  be  made 
use  of. 

On  Drying  the  Saltpetre. 

To  render  the  saltpetre  fit  to  be  made 
use  of  in  the  preparation  of  gunpowder, 
as  soon  as  it  is  purified,  it  may  be  dried 
by  either  of  the  two  following  processes. 
First,  by  exposing  it  to  the  open  air,  or  to 
the  sun,  during  some  hours,  upon  such  ta- 
bles as  are  used  for  drying  gunpowder. 
Secondly,  by  putting  it  into  a  shallow  caul- 
dron, unci  keeping  it,  for  the  space  of  two 
hours,  in  a  heat  of  from  40  to  50  degrees. 

In  either  case,  the  saltpetre  must  be  in- 
cessantly stirred  and  shaken,  that  it  may 
dry  quickly  and  equally. 

General  Remarks  on  the  foregoing  Process 

A  pretty  long  experience  has  shown  us, 
that  the  process  here  described  is  the 
most  simple,  and  the  most  economical. 

But,  to  spare  others  the  trouble  of  try* 
ing  such  means  of  improving  this  process 
as  have  occupied  our  attention,  but  which 
we  thought  it  right  to  reject,  we  shall 
submit  to  them  the  following  reflections. 

1.  It  has  been  tried  to  dissolve  the 
crude  saltpetre ;  to  crystallize  it ;  and  af> 
terwards  to  wash  it,  in  order  to  separate 
the  sea-salt  from  it. 

This  process  at  first  sight  appear? 
more  advantageous,  because  it  is  then 
unnecessary  to  bruise  the  saltpetre,  but 
it  is  attended  with  great  inconveniences- 


OCH 


OCH 


First,  the  crude  saltpetre,  dissolved  in 
fifty  parts  of  water  to  a  hundred,  and 
poured  into  the  crystallizing  vessel,  does 
not  deposit  the  same  quantity  of  saltpetre 
as  when  it  is  washed  before  it  is  dissolved. 
This  difference  takes  place,  because  the 
sea-salt,  which  exists  in  the  crude  saltpe- 
tre, facilitates  the  dissolution  of  the  ni- 
trate of  potash;  and  consequently,  the 
water  in  the  crystallizing'  vessel  must  ne- 
cessarily hold  in  solution  a  greater  quan- 
tity of  nitrate  of  potash,  when  the  crude 
saltpetre  is  dissolved,  than  when  it  is  pre- 
viously washed  in  cold  water,  and  there- 
by deprived  of  the  sea-salt  it  contained. 
Secondly,  the  washing  of  the  saltpetre, 
when  done  after  its  dissolution  and  crys- 
tallization, requires  forty  or  fifty  parts  of 
water  to  a  hundred,  instead  of  thirty-five. 

2.  It  has  been  tried  to  dissolve  the  salt- 
petre in  twenty  or  twenty -five  parts  to  a 
hundred;  to  take  away  the  muriate  of 
soda,  as  fast  as  it  is  precipitated  by  the 
boiling  of  the  liquor ;  to  dilute  this  solu- 
tion with  thirty  parts  of  fresh  water  to  a 
hundred,  and  then  to  carry  it  to  the  crys- 
tallizing vessel.  It  was  supposed,  that 
by  this  means,  the  washings  with  cold 
water  might  be  omitted,  or  considerably 
diminished.  But,  a  continued  boiling, 
kept  up  for  four  or  five  hours,  in  order  to 
separate  the  sea-salt,  is  attended  with  a 
great  waste  of  time,  of  fuel,  and  of  salt- 
petre; and  the  washings  are  still  indis- 
pensably necessary,  both  to  take  away  the 
colouring  matter,  and  to  extract  the  last 
portions  of  sea-salt 

3.  It  may  be  supposed,  that  it  would 
perhaps  be* possible  to  diminish  the  quan- 
tity oi  water  used  in  washing;  but  we 
roust  observe,  that  it  is  to  be  feared,  that 
when  the  saltpetre  contains  a  great  quan- 
tity of  sea-salt,  the  purification  of  it  would 
not  be  complete,  if  a  less  quantity  of  wa- 
ter were  made  use  of  than  that  we  have 
prescribed. 


4.  One  might  perhaps  be  tempted  to 
diminish  the  quantity  of  water  made  use 
of  in  the  solution  ;  but  we  are  convinced, 
by  repeated  experiments,  that  the  propor- 
tion we  have  pointed  out  is  the  most  pro- 
per :  if  it  is  augmented,  the  saltpetre  re- 
mains dissolved  in  the  liquor ;  if  it  is  de- 
creased, it  congeals  or  precipitates  itself 
in  a  mass.  We  found,  by  observation, 
that  the  degree  of  saturation,  most  proper 
for  our  operations,  was  between  the  sixty- 
sixth  and  sixty -eighth  degree  of  the  pese- 
liqueur. 

5.  It  might  also  be  thought,  that  it 
would  be  more  simple,  and  more  economi- 
cal, to  treat  the  solutions  of  crude  saltpe- 
tre with  potash  ;  but  it  is  to  be  feared, 
that  by  so  doing,  a  part  of  this  alkali 
might  have  the  effect  of  decomposing  the 
muriate  of  soda,  and  converting  it  into 
muriate  of  potash;  and  it  must  be  ob- 
served, that  the  last-mentioned  salt  is  by 
no  means  proper  tor  decomposing  earthy 
nitrates,  whatever  some  able  chemists 
may  have  said  of  it. 

It  therefore  appears  more  proper,  not 
to  treat  the  mother-waters,  nor  to  make 
any  use  of  potash,  till  all  the  sea-salt  has 
been  separated  by  evaporation. 

During  the  American  revolution  the  at- 
tention of  Congress  was  directed  to  the 
resources  of  saltpetre  for  the  manufac- 
ture of  gunpowder,  as  well  as  to  the  best 
means  of  purifying  it.  Several  essays  ac- 
cordingly appeared,  which  had  the  de- 
sired tendency.  Saltpetre  was  manufac- 
tured by  the  corruption  of  animal  and  ve- 
getable substances,  and  its  manner  of  pu- 
rification was  accordingly  improved.  The 
floors  of  tobacco  houses  were  dug  up,  and 
elixated  for  the  purpose.  But  at  this  pe- 
riod, the  United  States  is  supplied  from 
the  nitre  caves  in  the  western  country, 
ot  which  some  account  is  given  in  the  be- 
ginning  of  this  article- 


o. 


OAT.    See  Agriculture. 

OCHRE.  In  a  general  sense,  ochre  is 
an  earth  coloured  with  oxyd  of  iron,  and 
sometimes  with  other  metallic  oxvds. 
Ochres  are  yellow,  red,  and  brown.  They 
are  used  as  pigments,  and  for  this  purpose 
are  considerably  employed.  They  are 
found  in  abundance  in  the  United  States. 
They  constitute  a  variety  of  the  argilla- 
ceous genus.  Some  of  them  are  altered 
by  calcination,  hence  the  conversion  of  the 


yellow  to  the  red,  by  that  process.  This 
is  owing  to  a  further  oxydizement  of  the 
metal.  The  ferrugineous  or  iron  ochres 
are  the  most  common,  and  appear  to  have 
been  formed  by  the  decomposition  ot  iron 
pyrites,  or  by  the  gradual  oxydizement  or 
iron  in  contact  with  clay. 

OCH^  £ELL0.W}  See  Colour 

^J  "  *URNT    ?  Making. 
OCHRE,  Roman  _) 

A  very  fine  yeUow  ochre  may  be  made 


OIL 


OIL 


by  decomposing  copper  as  (sulphate  of 
iron,)  by  the  addition  of  potash  or  lime. 
Hence  yellow  wash  for  rooms,  is  often 
made  by  mixing*  copperas  with  half  its 
weight  of  lime,  in  a  sufficient  quantity  of 
water.  The  acid  unites  with  the  lime  into 
sulphate  of  lime  or  gypsum,  and  the  iron 
is  precipitated  in  the  form  of  oxyd,  which 
by  mixture  with  the  gypsum,  forms  the 
wash. 

OIL.  The  distinctive  characters  of  oil 
are  inflammability,  insolubility  in  water, 
and  fluidity,  at  least  in  a  moderate  tempe 
rature.  Oils  are  distinguished  into  fixed 
or  fat  oils,  which  do  not  rise  in  distilla- 
tion at  the  temperature  of  boiling-  water 
and  volatile  or  essential  oils,  which  do  rise 
at  that  temperature. 

Fixed  oils  are  obtained  by  pressure, 
sometimes  assisted  by  heat,  or  by  boilim 
in  water,  from  the  emulsive  seeds  or  ker 
nels  of  vegetables  ;  and  likewise  from  the 
fatty  parts  of  animals.  They  are  general- 
ly fluid  in  the  temperature  of  the  atmos- 
phere, but  some  of  them  have  a  conside 
rable  degree  of  firmness  or  solidity.  They 
have  a  very  smooth  feel ;  require  a  de 
gree  of  heat  much  superior  to  that  of  boil 
ing  water,  to  cause  them  to  rise  in  ebul 
lition ;  and  cannot  be  set  on  fire,  unless 
heated  to  this  degree.  The  use  of  the 
wick  of  a  lamp  consists  in  bringing  small 
portions  of  oil  to  its  extremity,  by  the  ca- 
pillary attraction  ;  where  they  become 
successively  volatilized  and  inflamed.  Oils 
are  remarkably  less  sonorous  than  water 
when  poured  out.  Fat  oils,  not  being  at 
all  dissipated  by  the  heat  of  the  utmos 
phere,  make  a  permanent  greasy  spot, 
when  they  fall  on  porous  substances. 

These  oils  are  decomposed  by  distilla- 
tion, and  afford  a  small  quantity  of  water 
loaded  with  a  peculiar  agid,  a  light  oil,  a 
dense  oil,  hydrogen,  and  carbonic  acid 
gas.  The  residue  consists  of  a  small 
quantity  of  charcoal. 

In  the  last  analysis  of  organized  sub- 
stances the  results  are,  hydrogen,  oxygen, 
nitrogen,  and  carbon,  which  appears  to  be 
their  basis.  By  what  combinations  or  su- 
per-compositions, they  are  made  to  exhi- 
bit the  variety  of  products  which  come 
under  our  observation,  can  in  few  respects 
be  ascertained  by  any  experiments  we  are 
yet  capable  of  making.  Lavoisier,  in  the 
Memoirs  of  the  French  Academy  lor  1784, 
collected  the  products  of  olive  oil  burned 
in  an  apparatus  properly  constructed,  to 
ascertain  their  nature  and  properties.  He 
obtained  79  parts  of  carbon,  and  21  of 
hydrogen,  from  100  of  the  oil.  From 
these  component  parts,  inferences  may  be 
formed  respecting  the  acid,  the  water, 
the  carbonic  acid,  and  the  hydrogen  gas, 


afforded  by  the  partial  decomposition  or 
combustions  of  this  fluid. 

The  light  oil,  produced  by  distillation 
of  fat  oils,  is  naturally  more  disposed  ta 
i  fly  off  by  heat,  and  leaves  less  coal  behind 
it,  than  the  fat  oil  itself.  This  property 
renders  it  useful  in  some  of  the  arts,  a* 
those  of  lapidaries,  seal  engravers,  and 
others,  who  grind  precious  stones  with 
fretting  powders.  The  oil  used  for  this 
purpose,  is  known  by  the  name  of  oil  of 
bricks,  which  is  made  by  igniting  pieces 
of  brick  which  had  imbibed  it.  in  order 
to  form  a  proper  notion  of  the  advantage 
of  this  fluid,  it  must  be  remarked,  that  alt 
grinding  produces  heat ;  that  this  heat 
would  speedily  evaporate  water,  and  ren- 
der common  oil  thick  ;  that,  if  neither 
water  nor  oil  were  present,  the  heat  would 
very  soon  increase  to  strong  ignition,  and 
injure  both  the  tool  and  the  substance 
operated  on.  The  oil  of  bricks  possesses 
neither  of  the  bad  qualities  of  the  two 
fluids  here  mentioned,  in  so  considerable 
a  degree,  and  is  therefore  preferred  for 
such  work  as  can  aflbrd  the  expense. 

Fat  oils,  by  exposure  to  the  air,  be- 
come rancid,  and  exhibit  a  disengaged 
acid,  which  may  be  washed  off  by  watetr. 
W  hen  they  are  exposed  to  the  air,  in  a 
thin  coat,  upon  the  surface  of  water,  they 
become  more  consistent,  like  wax,  by  ab- 
sorbing the  oxygen  of  the  atmosphere. 
The  oxygenized  muriatic  acid  produces 
this  change  more  speedily.  Agitation  in 
water,  particularly  if  acidulated,  separates 
a  mucilage  from  them.  They  combine 
with  barytes,  strontia,  magnesia,  and  lime, 
which  convert  them  into  saponaceous" 
compounds.  With  the  pure  alkalis  they 
form  common  soap.  They  do  not  unite 
with  ammonia  but  by  long  trituration. 

The  mineral  acids  unite  with  fat  oils,- 
and  form  compounds,  or  imperfect  soaps. 
Fuming  nitrous  acid  causes  them  to  take 
fire,  as  has  already  been  observed.  Sul- 
phur is  soluble  in  fat  oils,  by  a  digesting" 
heat ;  and  is  gradually  deposited  in  part 
from  them,  in  a  crystalline  form,  bv  coolr 
ing. 

Fixed  oils  seem  not  to  be  susceptible  of 
combination  with  pure  metallic  substan- 
ces, excepting  iron  and  copper,  upon 
which  they  act  in  a  sufficiently  distinct 
manner.  But  they  combine  witli  metallic 
oxydes,  and  form  with  them  tluck  con- 
crete combinations,  of  a  soapy  appearance, 
as  is  observable  in  the  preparation  of  un- 
guents and  plasters.  These  preparations 
have  not  yet  been  chemically  examined. 
Metallic  oxydes  are  likewise  boiled  in 
oils  to  give  them  the  quality  of  drying; 
quickly. 

Mr,  Sheldrake  has  observed,  that  oils 


OIL 


OIL 


thus  prepared  dry  by  forming  a  superfi- 
cial skin,  and  the  more  of  this  quality 
they  possess,  the  more  colours  mixed  with 
them  are  liable  to  change  by  keeping-.  He 
therefore  recommends,  to  dissolve  amber, 
or  copal,  in  the  oil,  to  dry  by  uniform  in- 
spissation  ;  and  with  this  to  mix  the  co- 
lours previously  ground  in  oil  of  turpen- 
tine. 

Mr.  Vanherman  has  lately  laid  before 
the  Society  of  Arts,  a  method  of  render- 
ing fish-oil  applicable  to  painting  ;  and  it 
appears  to  make  a  good  and  cheap  vehi- 
cle for  colours  exposed  to  the  weather, 
though  it  dries  but  slowly.  To  thirty- 
two  gallons  of  vinegar,  he  adds  l  v  lbs.  of 
litharge,  and  12  lbs.  of  sulphat  of  zinc, 
shaking  the  mixture  well,  twice  a  day  for 
a  week.  The  mixture  is  then  put  into  a 
tun  of  fish-oil,  with  which  it  is  well  shaken 
and  mixed  ;  and  the  next  day  the  clearer 
part,  about  seven-eighths  of  the  whole,  is 
poured  off.  Twelve  gallons  of  linseed  oil, 
and  two  of  oil  of  turpentine,  are  then  add- 
ed to  the  clear  part ;  and  this,  being  well 
shaken  together,  is  left  to  settle  for  two 
or  three  days,  when  it  will  be  lit  to  grind 
white  lead,  and  all  fine  colours  in.  These 
however  are  to  be  thinned  for  use  with 
linseed  oil,  and  oil  of  turpentine. 

For  cheap  paints  exposed  to  the  wea- 
ther, whiting  and  road  dirt  finely  sifted, 
are  to  be  mixed  with  lime  water  to  the 
consistence  of  mortar;  to  this  may  be 
added  almost  any  pigment,  ground  with 
the  sediment  of  the  prepared  oil,  in  the 
proportion  of  one  part  to  two,  of  the  lime- 
water  already  used ;  and  the  whole  is  to 
be  thinned  for  use,  by  adding  to  every 
eight  pounds,  a  quart  of  linseed  oil,  and 
as  much  of  a  mixture  of  the  prepared  oil 
with  lime  water.  The  proportions  of  this 
mixture  are  not  mentioned. 

If  two  ounces  of  litharge  be  added,  to  a 
gallon  oflinseed  oil,  and  well  shaken  every 
day  for  a  fortnight ;  and  the  clear  part, 
mixed  with  half  a  pint  of  oil  of  turpentine, 
be  exposed  to  the  sun  for  three  days  in 
shallow  pans,  Mr.  Vanherman  informs  us, 
it  will  be  as  white  as  nut-oil.  If  half  a 
pound  of  frankincense  be  dissolved  in  a 
quart  of  oil  of  turpentine,  and  added  to  a 
gallon  of  this  bleached  oil;  and  white  lead, 
ground  in  oil  of  turpentine,  be  thinned  for 
use  with  this  mixture;  he  asserts  that  it 
will  be  quite  dry  and  void  of  smell  in  four 
hours. 

It  is  likewise  desirable  to  purify  the 
coarse  fish  oils,  for  the  purposes  of  bum* 
mg,  and  of  some  manufactures.  This  may 
be  effected  to  a  certain  degree,  by  shaking 
k  with  limewater,  or  with  a  little  chalk, 
and  slaked  lime  and  water.  But  to  pu- 
rify it  thoroughly,  an  ounce  of  powdered 


chalk,  a  quarter  of  an  ounce  of  lime  slak- 
ed in  the  air,  and  half  a  pint  of  water, 
should  be  well  mixed,  with  a  gallon  of  the 
stinking  oil  ;  and  when  it  has  stood  some 
hours,  a  pint  of  water  and  two  ounces  of 
pearl  ashes,  should  be  added,  and  the 
mixture  kept  simmering  over  the  fire,  till 
the  oil  appears  of  a  light  amber  colour  s 
then  add  an  ounce  of  salt  dissolved  in  half 
a  pint  of  water,  boil  half  an  hour  longer, 
and  let  the  mixture  stand,  till  the  oil  se- 
parates. If  it  be  required  still  purer,  the 
oil  after  being  poured  off,  may  be  treated 
in  a  nearly  similar  manner,  hut  without 
heat,  with  an  ounce  of  chalk,  a  quarter 
of  an  ounce  of  pearl  ashes,  and  half  an 
ounce  of  salt.  If  an  oil  of  somewhat 
more  consistence  be  wanted,  kitchen  stuff 
may  be  added  to  it,  while  it  continues 
hot. 

To  purify  rape  oil  for  burning  in  lamps, 
Curaudeau  advises,  to  add  1U0  parts  of 
oil,  one  part  of  sulphuric  acid,  diluted 
with  six  of  water ;  shake  the  mixture  well; 
and  then  let  it  settle:  or  one  part  of 
wheat  flour,  mixed  with  ten  of  water,  and 
expose  it  to  a  heat  not  exceeding  212°, 
till  the  water  is  evaporated. 

In  the  assaying  of  metals,  fixed  oils  are 
sometimes  employed  to  reduce  the  me- 
tallic oxydes.  Berthollet  has  given  an 
ingenious  and  simple  process  for  effecting 
instantaneously  a  real  combination,  be- 
tween fixed  oil,  and  metallic  oxyde,  that 
is,  for  preparing  a  metallic  soap.  It  con- 
sists in  pouring  a  metallic  solution,  into  a 
solution  of  common  soap.  The  acid  of 
the  metallic  solution,  combines  with  the 
fixed  alkali  of  the  soap;  and  the  metallic 
oxyde,  is  then  precipitated  in  union  with 
the  oil, to  which  it  communicates  a  colour. 
In  this  manner,  soap  of  a  beautiful  green 
colour,  may  be  prepared  with  sulphat  of 
copper  ;  and  with  sulphat  of  iron,  a  clear 
deep  brown  soap.  Fourcroy  thinks  these 
compounds  might  be  very  useful  in  paint- 
ing. 

Scheele  discovered,  that  when  oil  of 
sweet  almonds,  olives,  rapeseed,  or  lin- 
seed,  is  combined  with  oxyde  of  lead,  with 
the  addition  of  a  little  water,  there  is  a 
matter  separated  from  the  oil,  which 
swims  on  the  surface  of  the  liquor,  and  to 
which  he  gave  the  name  of  the  mild  prin- 
ciple. On  evaporating  this  supernatant 
water,  the  principle  dissolved  in  it,  causes 
it  to  assume  the  consistency  of  syrup  : 
when  exposed  to  a  strong  heat,  it  takes 
fire  ;  one  part  is  volatilized  in  distillation, 
without  burning:  the  coal  which  it  leaves 
is  light:  it  does  not  crystallize  ;  nor  does 
it  seem  to  be  susceptible  of  fermentation. 
Nitric  acid,  distilled  on  this  matter  four 
times  successively,  changes  it  into  oxalic 


OIL 


OIL 


acid.  This  mild  principle  of  Scheele's 
appears  to  be  a  sort  of  mucilage. 

The  dense  animal  oils,  such  as  butter, 
tallow,  fat,  the  oil  of  the  whale,  and  the 
like,  exceedingly  resemble  vegetable  fix- 
ed oils.  They  appear,  however,  to  con- 
tain a  proportion  of  nitrogen,  or  animaliz- 
ed  matter,  probably  in  the  state  of  serum 
or  gelatine.  The  volatile  oil,  obtained  by 
attenuating  animal  oil,  by  a  number  of 
successive  distillations,  is  called  Dippcl's 
animal  oil.  Macquer  observes,  that  it 
may  be  rendered  almost  as  white,  thin  and 
volatile  as  ether,  and  is  then  capable  of 
acting  upon  the  brain  and  nervous  system, 
in  a  dose  of  from  four  to  ten  or  twelve 
drops,  incorporated  with  some  proper  ve- 
hicle. Kouelle  recommends,  to  rectify  it 
by  distillation  with  water. 

It  is  much  more  difficult  to  obtain  this 
oil  in  a  pure  state,  from  hxed  oils,  than 
from  gelatinous  matters,  of  which  harts- 
horn is  to  be  preferred.  It  is  necessary  to 
change  the  vessels  at  each  successive  dis- 
tillation, or  else  to  clean  them  perfectly, 
because  a  very  small  part  of  the  thicker 
and  less  volatile  oil,  is  sufficient  to  spoil 
a  large  quantity,  of  that  which  is  more 
highly  rectified.  Beaume  has  observed, 
that  this  operation  may  be  greatly  abridg- 
ed by  taking  care  to  receive  none  but  the 
most  volatile  part  in  each  distillation,  and 
to  leave  a  large  residuum,  which  is  to  be 
neglected,  and  only  the  more  volatile  part 
is  to  be  further  rectified.  By  this  method, 
we  may  obtain  in  three  or  four  distilla- 
tions, a  considerable  quantity  of  fine  oil  of 
Dippel,  which  could  not  be  obtained  after 
50  or  60  distillations,  without  attending  to 
this  circumstance.  And  Monnet  asserts, 
that,  by  mixing  acids  with  animal  oil, 
their  rectification  may  be  very  much  faci- 
litated. 

The  oil  of  Dippel  must  be  kept  in  clean 
glass  bottles,  with  ground  stopples,  and 
exposed  as  little  as  possible  to  the  air, 
because  its  volatile  parts  fly  off,  and  the 
remainder  becomes  coloured. 

Fourcroy  distinguishes  vegetable  fat 
oils  into  three  classes.  In  the  first,  he 
places  such  as  are  congealable  by  cold, 
thicken  very  slowly,  by  exposure  to  air, 
form  soaps  with  acids,  and  require  an  ad- 
dition of  sulphuric  acid  to  that  of  nitre,  in 
order  to  inflame  them. 

Most  metallic  oxyds  are  decomposed 
by  the  fixed  oils  at  a  boiling  heat :  those, 
however,  that  are  commonly  employed 
for  this  purpose,  are  minium  and  litharge. 
If  either  of  these  substances,  ground  to  a 
very  fine  powder,  be  put  in  a  kettle  with 
a  little  water  and  some  fat  oil,  and  the 
whole  be  well  mingled  by  constant  stir- 
ring, it  will  be  found  that  the  oil,  when 


nearly  at  the  temperature  of  boiling  wa- 
ter, first  abstracts  part  of  the  oxygen 
from  the  oxyd,  and  then  dissolves  pretty- 
rapidly  the  oxyd  itself.  In  consequence 
of  this,  the  oil  becomes  thick  and  colour- 
ed, acquires  a  peculiar  odour,  and  when 
cooled  becomes  opake,  and  ot  a  soft  pastv 
consistence.  By  continuing  the  heat  af- 
ter the  solution  of  the  oxyd,  till  the  water 
is  completely  driven  off,  the  residue  on 
cooiing  acquires  nearly  the  consistence  ot' 
wax,  and  is  known  in  pharmacy  by  the 
appellation  of  pLister.  If,  instead  of  tat 
oil,  drying  oii  be  made  use  of,  the  mixture 
cannot  be  made  harder  than  stiff  paste. 
Deyeux  has  shown  that  fat  oils,  when 
previously  mixed  with  mucilage,  are  ex- 
actly similar  in  this  respect  to  the  drying 
oils.  Plaster  is  not  soluble  either  in  al- 
cohol or  water,  in  which  respect  itdilfers 
materially  from  the  proper  soaps,  to 
which  it  lias  been  compared  by  some  che- 
mists. If,  after  the  oil  and  litharge  have 
combined  together,  the  water  is  pouted 
off,  instead  of  being  dissipated  by  a  fur- 
ther continuation  of  the  heat,  and  then 
evaporated  considerably  in  a  separate 
vessel,  it  will  be  found  to  have  acquired 
a  thick  syrupy  consistence  and  a  saccha- 
rine taste. 

Olive  OH. 

The  fruit  of  the  olive  tree  (Olea  Euro- 
pea)  when  ripe,  is  of  a  dark  purple  co- 
ioui  ,  and  both  in  size  and  shape  resembles 
a  long  plum  :  it  consists  of  a  nut  or  stone 
covered  by  a  fleshy  pulp,  in  the  latter  of 
which  are  the  cells  that  contain  the  oil ; 
the  interior  nut  also  contains  an  oil,  but 
of  a  bitter  disagreeable  taste.  The  fruit 
as  soon  as  gathered  is  broken  in  a  mil], 
care  being  taken  to  set  the  mill-stones  at 
such  a  distance  as  to  avoid  crushing  the 
nut  of  the  olive.  The  pulp  thus  prepared 
is  put  into  bags  made  of  rushes,  and  sub- 
jected to  a  moderate  pressure,  by  which 
a  considerable  quantity  of  greenish  semi- 
transparent  oil  is  obtained,  which  from 
its  superior  excellence  is  called  virgin 
oil.  The  marc  remaining  after  this  first 
operation  is  broken  to  pieces,  moistened 
with  a  little  warm  water,  and  again  re- 
turned to  the  press  ;  a  mixture  of  oil  and 
water  flows  out,  which  soon  separates 
spontaneously  by  rest.  This  oil,  thougu 
inferior  to  the  former,  is  still  of  a  very 
good  quality,  and  fit  for  the  table.  The 
marc  being  again  broken  to  piece*-, 
drenched  with  water,  and  fermented  iu 
large  cisterns,  is  for  the  third  and  last 
time  submitted  to  the  ful]  force  of  the 
press,  by  w  hich  a  considerable  quantity  of 
oil  is  obtained,  very  valuable  to  the  soap- 
boilers and  other  manufacturers.  In  some 


OIL 


OIL 


countries,  particularly  in  Spain,  the  olives, 
instead  of  being  gathered  by  hand,  are 
beaten  down,  by  which  the  ripe  and  un- 
ripe are  mixed  tog-ether  ;  to  these  also  are 
added  such  as  have  fallen  of  themselves, 
and  are  therefore  more  or  less  decayed. 
Of  this  indiscriminate  collection  a  large 
heap  is  made,  which  soon  begins  to  fer- 
ment; in  this  state  the  olives  are  ground, 
and  strongly  pressed  in  the  usual  manner, 
"by  which  mode  of  proceeding  a  larger 
quantity  of  oil  is  indeed  obtained,  and 
-with  less  trouble,  but  of  a  rank  disagree- 
able flavour,  intolerable  to  any  but  those 
■who  have  from  childhood  been  accustom- 
ed to  it. 

Recently  drawn  virgin  oil  has  a  bland 
almost  mucilaginous  taste,  with  a  slight 
but  agreeable  flavour :  if  exposed  to  the 
air  in  an  open  bottle  or  cask,  a  white  fi- 
brous and  probably  albuminous  matter  is 
deposited,  the  supernatant  oil  becoming 
clear,  and  of  a  dilute  yellow  colour  ;  the 
oil  being  poured  off  into  a  fresh  vessel,  a 
second  deposition  takes  place,  after  which 
the  oil,  if  put  in  clean  glass  vials,  may 
be  kept  for  a  considerable  time  without 
alteration.  If  the  oil  is  allowed  to  stand 
©n  the  white  matter,  it  becomes  in  a  few 
weeks  very  rancid ;  and  the  common  oil, 
even  when  properly  managed,  cannot  be 
preserved  in  casks  longer  than  a  year  and 
a  half,  or  two  years,  at  the  farthest.  The 
specific  gravity  of  olive  oil  is  =0.9153; 
it  boils  at  about  100°  Fahr.  and  congeals 
at  36°  Fahr.  The  readiness  with  which 
it  freezes  renders  it  improper  for  lamps, 
especially  in  cold  countries  ;  but  by  pre- 
viously exposing  the  oil  in  an  open  clear 
glass  "vial  to  the  sunshine,  it  may  be  so  far 
amended  in  this  respect,  as  to  continue 
fluid  at  21°  Fahr.  Olive  oil  is  often  so- 
phisticated by  poppy-seed  oil,  and  thus  is 
rendered  somewhat  drying,  a  property 
which  the  genuine  produce  of  the  olive 
never  exhibits.  In  those  countries  where 
>t  is  produced,  it  is  employed  in  food,  as 
butter  is  with  us  :  the  inferior  sorts  are 
burnt  in  lamps,  or  made  into  soaps,  for 
the  most  part  of  a  finer  quality  than  those 
that  are  composed  of  animal  oils.  It  is 
used  in  medicine  sometimes  internally, 
but  generally  externally,  combined  with 
wax,  litharge,  &c.  into  cerates  and  plas- 
ters. 

Cornel  Oil. 
The  only  oil  resembling  that  from  the 
olive,  in  being  contained  not  in  the  seed, 
but  in  the  pulpy  fruit  of  a  vegetable,  is 
cornel  oil.  The  berries  of  this  shrub 
(Cornus  sanguinea,  JAnn)  being  collected 
when  quite  ripe,  and  then  laid  in  heaps 
for  a  few  days  in  order  to  mellow,  are  to 
be  reduced  to  a  pulp,  and  pressed  without 


heat  in  the  usual  manner.  By  this  treat- 
ment, from  22  lbs.  avoirdupois,  may  be 
obtained  somewhat  more  than  four  wine 
pints  of  a  fat  somewhat  viscid  oil,  of  a 
bright  green  colour,  and  equally  destitute 
of  any  unpleasant  flavour  as  the  best  olive 
oil.  When  heated  with  nitric  acid,  it  is 
converted  to  a  lemon-yellow  butter  or 
wax.  By  boiling  with  litharge,  it  becomes 
drying  ;  when  spread  thin  on  water,  and 
exposed  to  the  air  for  a  month,  it  is  con- 
verted into  a  white  wax.  It  does  not 
freeze  so  readily  as  olive  oil,  and  lasts  ra- 
ther longer  than  this  when  used  in  a 
lamp. 

Jllmond  Oil. 
This  is  procured  either  from  the  sweet 
or  bitter  almond.  The  almonds  are  first 
put  into  a  coarse  hempen  or  hair  sack, 
and  shaken  violently,  in  order  to  detach, 
by  rubbing  against  each  other  and  the 
sides  of  the  sack,  the  outer  brown  skin, 
which  if  retained  is  apt  to  give  a  bitter 
taste  to  the  oil :  they  are  then  bruised  and 
made  into  a  paste,  and  pressed  in  the 
usual  manner.  100  lbs.  of  almonds  af- 
ford, by  the  first  expression,  25  lbs.  of 
oil,  and  from  the  marc,  when  impregnated 
with  the  steam  of  hot  water,  may  be  pro- 
cured 15  lbs.  more  of  an  interior  kind. 
Almond  oil,  when  fresh,  is  of  a  light 
greenish  yellow  colour,  and  is  somewhat 
turbid,  but  by  time  it  becomes  clear  and 
colourless  :  it  is  slightly  sweetish  to  the 
taste,  and  has  little  or  no  odour.  Its  spe- 
cific gravity  is  =  0.917.  The  degree  at 
whicii  it  congeals  is  variously  stated  at 
19°  Fahr.  and  8°  Fahr.;  the  former  pro- 
bably relates  to  the  fresh-drawn  oil.  The 
only  difference  between  the  oil  from 
sweet  and  that  from  bitter  almonds  is, 
that  the  latter  may  be  kept  the  longest 
without  growing  rancid.  On  account  of 
its  high  price,  at  least  in  most  of  the  coun- 
tries of  Europe,  it  is  almost  entirely  re- 
stricted to  medical  uses. 

Poppy-seed  Oil,  or  Pink  Oil. 
The  oil  is  extracted  by  cold  drawing 
from  the  seeds  of  the  large  white  poppy 
(Papaver  somniferum.  J  Ann.)  which  is 
largely  cultivated  for  this  purpose  in 
France,  the  Netherlands,  and  various 
parts  of  Germany.  It  is  transparent  and 
nearly  colourless,  and  when  well  prepar- 
ed has  no  other  taste  or  flavour  than  a 
slight  one  of  nut-kernels.  Its  specific 
gravity  is  =  0  9288 :  it  is  one  of  the  na- 
turally drying  oils,  and,  like  all  of  that 
class,  is  frozen  with  difficulty;  it  may  be 
cooled  down  to  0°  of  Fahr.  without  con- 
gealing When  employed  in  food,  it  is 
scarcely  to  be  distinguished  from  olive 
oil,  and  indeed  this  latter  is  very  common- 


OIL 


OIL 


ly  adulterated  with  it.  As  to  the  quanti- 
ty of  oil  yielded  by  a  given  weight  of  the 
seeds,  authors  are  by  no  means  agreed, 
and  much  no  doubt  depends  not  only  on 
the  mode  of  extracting  it,  but  also  on  the 
season  and  country  in  which  the  seeds  are 
produced :  from  100  lbs.  of  fresh  seeds, 
some  state  the  produce  of  oil  at  25  lbs. 
and  others  at  58  lbs.  It  is  used  both  tor 
food  and  in  the  composition  of  varnishes, 
but  is  very  unfit  to  burn  in  a  lamp. 

Linseed  Oil. 

The  seeds  of  the  common  flax,  from 
which  this  oil  is  produced  consist  of  a 
white  kernel  covered  by  a  thin  brownish 
shell.  As  it  is  impossible  to  separate  the 
shell  from  the  kernel,  the  entire  seed 
must  be  submitted  to  the  press ;  but  if 
thus  treated  without  any  previous  prepa- 
ration, the  quantity  of  oil  obtained  is  com- 
paratively small,  on  account  of  a  strong 
mucilage  that  resides  in  the  shell,  and  ab- 
sorbs a  large  proportion  of  the  oil  as  it  is 
forced  out  of  the  kernel.  For  this  rea- 
son, and  because  the  cold  drawn  oil  is  not 
so  fit  for  the  purposes  to  which  linseed 
oil  is  generally  applied  as  that  which  is 
hot  drawn,  the  following  method  is  gene- 
rally taken  to  destroy  the  mucilage  be- 
fore the  application  of  the  press.  An  iron 
vessel  like  a  sand-bath,  and  capable  of 
containing  some  bushels,  is  fixed  in  a  fur- 
nace: it  is  then  filled  with  linseed,  and 
heated  by  a  moderate  fire,  care  being  ta- 
ken to  stir  up  its  contents  from  time  to 
time,  that  every  part  may  be  equally 
roasted;  at  first  there  arises  an  abundance 
of  aqueous  vapour,  which,  as  the  heat  is 
increased,  is  followed  by  dense  blackish 
fumes  of  a  very  nauseous  odour.  The 
torrefaction  being  completed,  the  paste  is 
pressed  in  the  mill  in  the  usual  way. 

The  proportion  of  oil  yielded  by  this 
seed  is  about  20  per  cent  :  its  specific 
gravity  is  =  0  94';3.  It  is  not  congealed 
except  by  a  cold  below  0°  Fahr.  its  point 
of  ebullition  is  about  600°  of  the  same 
thermometer.  The  cold  drawn  oil  has  a 
high  yellow  colour,  is  very  unctuous  and 
unpleasant  both  to  the  taste  and  smell ; 
by  exposure  to  the  air  and  light,  it  be- 
comes drying.  The  hot  drawn  oil  is  of  a 
high  yellowish  red  or  deep  wine  colour; 
it  is  still  more  nauseous  than  the  former  ; 
it  is  of  a  thicker  consistence,  and  dries 
without  much  difficulty  in  the  air,  more 
especially  if  it  has  been  boiled  with  a  lit- 
tle litharge.  Linseed  oil  is  employed  a  lit- 
tle in  medicine  j  but  the  great  demand  tor 
it  is  in  the  coarser  kinds  of  painting,  par- 
ticularly such  as  is  not  much  exposed  to 
the  weather,  as  floor  cloths,  &c. 
YOL.  IT. 


Hempseed  Oil. 
This  oil  is  of  a  green  colour,  and  is 
strongly  impregnated  with  the  peculiar 
odour  of  the  plant.  The  proportion  of 
oil  that  hempseed  affords  is  from  20  to  25 
per  cent-  In  its  general  properties,  uses, 
and  mode  of  preparation,  it  closely  re- 
sembles the  preceding. 

Oils  of  JHustard-seed,  Cole-seed,  Rape-seed, 
and  Sutiflower-seed. 
These  oils  are  less  coloured  and  less 
highly  flavoured  than  the  two  preceding; 
they  are  very  little  liable  to  dry  by  expo- 
sure to  the  air,  which,  together  with  their 
moderate  price,  induces  a  large  consump- 
tion of  them  by  the  wool-dressers,  in  or- 
der to  preserve  the  wool  from  the  attacks 
of  moths  and  other  insects ;  and  by  the 
leather-dressers. 

Nut- Oil. 

This  is  obtained  chiefly  by  cold  draw- 
ing from  the  kernels  either  of  the  walnut 
or  of  the  hazle-nut.  In  the  warm  climate 
of  the  south  of  Europe  these  fruits  come 
to  their  full  perfection,  and  will  yield  by 
proper  management  full  half  ..heir  weight 
of  oil.  Recent  cold  drawn  nut  oil  is  by 
many  preferred  to  olive  oil  on  account  of 
the  exquisite  nut  flavour  which  it  retains  : 
th«  hot  drawn  has  an  empyreumatic  taste, 
and  is  no  longer  fit  for  the  table ;  it  is, 
however,  in  high  request  by  the  painter, 
as  being  eminently  drying",  much  less  co- 
loured than  linseed  oil,  and  capable  of 
bearing  the  injuries  of  the  weather  better 
than  any  other  oil. 

Beech-nut  Oil. 
Several  ineffectual  attempts  have  been 
made  to  manufacture  this  oil  with  profit 
from  Enghsii  beech  mast.  Various  causes 
have  probabiy  concurred  to  occasion  the 
failure,  particularly  the  inexpertness  in 
the  method  of  extraction,  and  in  all  pro- 
bability a  real  defect  of  oil  compared  to 
that  contained  in  the  beech-nuts  of  France 
and  the  south  of  Germany.  The  follow- 
ing is  the  method  adopted  by  some  manu- 
facturers, and  appears  upon  the  whole  to 
be  the  best.  The  nuts,  when  separated 
from  the  outer  prickly  receptacle,  are 
passed  through  a  mill,  the  stones  of  which 
are  set  sufficiently  wide  to  break  off  the 
outer  shell  without  materially  bruising 
the  kernel,  after  which,  by  means  of  the 
common  winnowing  machine,  the  shells 
are  got  rid  of  The  decorticated  nuts  are 
then  thrown  into  scalding  water,  and  all 
those  that  swim  are  rejected  as  being 
mouldy  and  worm  eaten,  and  therefore 
communicating  a  bad  taste  to  the  oil :  the 
X 


OIL 


OIL 


rest  are  reduced  to  a  pulp,  and  then  cold 
drawn,  when  they  will  be  found  to  yield 
15  per  cent  of  a  clear  light  coloured 
nearly  insipid  oil,  to  the  full  as  good  as 
common  olive  oil.  The  marc  being  now 
slightly  torrefied  and  again  pressed,  will 
afford  12  per  cent,  more  of  an  inferior  oil, 
and  the  dry  residue  is  an  excellent  food 
for  cattle,  much  better  than  common  oil 
cake. 

Oil  of  Ben.    Oleum  Balani  of  the  an- 
cients. 

This  oil  is  procured  by  expression  from 
the  decorticated  seeds  of  the  Guilandia 
Moringa,  a  tree  that  grows  in  Ceylon- 
Ethiopia,  Egypt,  and  Arabia.  100  lbs.  of 
the  seeds  yield  23  lbs.  of  a  yellowish  lim- 
pid oil,  inodorous,  insipid,  and  which  does 
not  become  rancid  by  exposure  to  the 
air.  On  this  account  it  is  much  used  by 
the  Italians  as  the  basis  of  their  perfumed 
oils,  which  are  commonly  prepared  by 
filling  a  covered  dish  with  alternate  layers 
of  cotton  soaked  in  Ben  oil,  and  flowers 
of  jasmine,  violet,  orange,  he.  after  the 
dish  has  been  set  in  hot  water,  or  in  the 
sunshine  for  a  few  days,  its  contents  are 
unpacked,  and  the  oil  squeezed  out  of  the 
cotton,  which  by  this  simple  process  is 
found  to  be  highly  impregnated  with  the 
aromatic  qualities  of  the  flowers. 

There  are  several  other  kinds  of  ex- 
pressed oils  employed  in  various  countries 
as  food,  or  in  lamps,  &c.  but  of  which  we 
shall  only  particularize  the  two  following, 
as  being  specimens  of  the  vegetable  but- 
ters. 

Butter  of  Cacao. 
This  oil  is  procured  from  the  chocolate 
nut,  the  fruit  of  the  Theobroma  Cacao. 
The  nuts  are  first  gently  roasted  till  the 
thin  outer  husk  shells  off,  and  are  then 
beaten  up  into  a  smooth  thin  paste  by  the 
addition  of  eight  times  their  weight  of 
warm  water.  This  mixture  being  then 
kept  at  a  gentle  boiling  heat  for  some 
hours,  a  liquid  oil  rises  to  the  surface, 
which,  when  the  fire  is  withdrawn,  con- 
cretes into  a  sebaceous  matter  of  a  gray 
colour,  and  amounting  to  about  45  per 
cent  of  the  entire  nuts  This  oil  may  be 
rendered  nearly  white  by  repeated  wash- 
ing iivscalding  water.  It  has  little  or  no 
taste,  but  retains  for  a  long  time  the  deli- 
cate flavour  of  chocolate,  and  appears  to 
be  the  least  disposed  of  any  of  the  oils  to 
become  rancid.  It  is  employed  in  Ameri- 
ca as  an  article  of  food,  and  in  the  compo- 
sition of  unguents  and  medicated  soaps. 

Palm  Oil. 
Many  of  the  palms  produce  a  hard  nut 
like  a  date  stone,  but  abounding  in  oil. 
Of  these  the  two  principal  are  the  Cocos 


butyracea  and  Eleaeis  guineensis. 
fruit  when  ripe  is  heaped  up  and  slightly 
fermented,  in  order  in  some  measure  to 
soften  it ;  being  then  coarsely  pounded,  it 
is  macerated  in  hot  water,  and  thus  by 
degrees  parts  with  its  oil,  which  collects 
on  the  surface  of  the  water,  and  by  cool- 
ing concretes  into  a  solid  cake  :  it  is  pun. 
fied  by  washing  in  hot  water,  and  is  then 
fit  for  use.  It  has  a  light  lemon  yellow 
colour,  little  or  no  taste,  but  a  high  odour 
and  flavour  like  that  of  the  Florentine 
iris:  by  long  keeping  it  becomes  rancid, 
and  then  is  nearly  white  and  almost  with- 
out odour.  It  is  largely  used  by  the  ne- 
groes in  Africa  and  the  West  Indies  as 
food,  and  in  Europe  is  employed  in  medi- 
cine, and  in  the  composition  of  the  best 
yellow  soap. 

Oil  of'  Sun -flower  seed. 

Dr.  J.  Morgan,  in  the  Transactions  of 
the  American  Philosophical  Society,  has 
given  an  essay  on  this  subject,  of  which 
the  following  is  a  summary. 

The  grinding  of  the  sun-flower  seeds, 
and  expressing  of  oil  from  the  same,  is  a 
manufacture,  which,  as  far  as  can  be  yet 
learned,  was  first  begun  among  the  Mora- 
vian brethren  at  Bethlehem,  and  reflects 
honour  upon  them,  whilst  it  affords  the 
public  a  new  substance  very  beneficial  in 
a  variety  of  purposes,  but  more  especial- 
ly, as  it  may  serve  for  a  sallad  oil,  and  for 
other  uses  of  diet  and  medicine,  in  the 
place  of  olive  oil. 

From  experiments  already  made  at 
Bethlehem,  it  is  found  that  a  bushel  of  the 
sun-flower  seed  will  yield,  on  expression, 
near  a  gallon  of  mild  oil.  The  gentleman, 
who  is  appointed  by.  the  community  there 
to  superintend  their  mills,  designs,  as  we 
are  informed,  to  pursue  a  further  course 
of  experiments  on  this  subject,  the  result 
of  which,  we  hope,  will  be  communicated 
to  this  society. 

Our  correspondent  at  Lancaster  informs 
the  society,  that  some  persons  in  the 
neighbourhood  of  that  place,  have  also 
expressed  a  quantity  of  oil  from  the  seeds 
of  the  sun-flower.  His  account  is  as  fol- 
.ows. 

The  person,  who  has  raised  the  great- 
est quantity  of  the  sun-flowers  with  us, 
informs  me,  that  one  hundred  plants,  set 
about  three  feet  distance  from  each  other, 
in  the  same  manner  as  Indian  corn  is  com- 
monly planted,  will  produce  one  bushel  of 
seed,  without  any  other  trouble  than  that 
of  putting  the  seed  into  the  ground,  from 
which  he  thinks  one  gallon  of  oil  may  be 
made.  1  observed  the  land,  on  which  he 
planted  the  sun-flowers,  to  be  of  the  mid- 
dling sort,  and  that  he  took  no  pains  to 
hill  them,  or  even  to  loosen  the  ground 


OIL 


OIL 


about  them,  which,  from  my  own  observa- 
tion on  some  planted  in  a  neighbour's  gar- 
den, I  take  to  be  of  considerable  use. 

As  the  sun-flower  is  a  plant  of  great  in- 
crease, and  requires  much  nourishment, 
hilling  does  not  seem  so  good  a  method 
as  that  of  setting  the  seed  or  plant  in  a 
hole,  and  when  the  plant  is  about  a  yard 
high,  to  throw  in  the  mould  round  the 
stalk,  so  that  the  surface  of  the  ground 
may  be  even  about  it.  By  an  estimate 
made  it  appears,  .that  one  acre  of  land 
will  yield  to  the  planter  between  forty  and 
fifty  bushed  of  seed,  which  will  produce 
as  many  gallons  of  oil.  The  process  for 
making  or  extracting  the  oil  is  the  same 
as  tfiat  of  making  linseed  oil,  which  I 
make  no  doubt  the  Society  is  acquainted 
with,  and  therefore  shall  not  trouble  you 
with  it. 

The  success  attending  the  trials  alrea- 
dy made,  give  the  greatest  encourage- 
ment to  prosecute  this  useful  discovery. 
And  as  the  seeds  of  the  sun-flower  are 
at  this  time  nearly  ripe,  and  in  a  proper 
state  for  extracting  the  oil  from  them,  it 
may  be  of  service  to  lay  these  facts  be- 
fore the  public.  Such  as  may  have  an  in- 
clination to  make  trials  on  this  subject, 
and  are  not  at  present  furnished  with  a 
sufficient  quantity  of  seed  for  pressing  out 
an  oil,  may  now  supply  themselves  with 
enough  to  plant  for  making  experiments 
the  ensuing  year. 

For  the  information  of  those  who  have 
both  opportunity  and  inclination  to  extend 
the  inquiry,  and  render  this  a  valuable 
branch  of  business,  but  are  not  acquaint- 
ed with  the  general  principles  upon  which 
oil  is  obtained,  by  expression  from  vege- 
table substances,  it  may  be  proper  to  ob- 
serve, that  the  kernels  of  fruits,  such  as 
walnuts,  hickory  nuts,  filberts,  almonds, 
peaches,  &c.  and  the  seeds  of  many  plants, 
as  mustard,  rape,  poppy,  flax,  sun-flower, 
&c.  contain  a  large  portion  of  mild  oil. 
In  order  to  obtain  the  oil,  the  kernels  or 
seeds  are  commonly  rubbed  to  powder,  or 
ground  in  mills.  They  are  then  put  into 
a  strong  bag,  made  of  canvas  or  woollen 
cloth,  and  committed  to  a  press  between 
iron  plates,-  by  which  the  oil  is  squeezed 
out,  and  is  received  or  conducted  into  a 
proper  vessel  to  collect  it  The  plates  of 
the  press  are  often  heated,  either  in  boil- 
ing water  or  before  the  fire.  Many  heat 
the  mash  itself  in  a  large  iron  pot,  stirring 
it  about  w  ith  a  stick  or  piece  of  wood,  to 
prevent  its  burning,  which,  when  it  hap- 
pens, greatly  injures  the  oil,  and  gives  it 
a  burnt  smell  and  taste,  or  disposes  it  to 
become  rancid  in  a  short  time  When  the 
oil  is  drawn  without  the  assistance  of 
heat,  it  is  known  by  the  name  of  cold 


drawn  oil,  and  is  more  valuable  than  when 
heat  is  used,  but  it  is  not  obtained  in  the 
same  quantity.  It  is  milder,  and  may  be 
kept  longer  without  spoiling. 

In  a  cold  season  of  the  year,  a  certain 
degree  of  heat  is  absolutely  necessary. 
But  if  the  oil  is  designed  for  aliment  or 
medicine,  the  plates  of  the  press  should 
be  heated  in' boiling  water  only.  When 
the  oil  is  intended  for  other  uses,  the 
plates  may  be  made  hotter,  as  heat  expe- 
dites the  separation  of  the  oil,  and  gives 
a  greater  produce;  but  then  care  should 
be  taken  not  to  injure  the  subject  by  burn- 
ing. 

Sometimes  the  subject,  when  ground, 
appears  almost  like  a  dry  powder.  It  is 
then  said  to  be  meagre,  and  requires  to  be 
exposed  to  the  vapours  of  boiling  water, 
which  is  done  either  by  tying  it  up  in  a 
bag,  or  putting  it  into  a  sieve,  and  plac- 
ing it  over  the  steam.  By  this  impregna- 
tion, it  will  yield  its  oil  more  readily,  and 
in  greater  quantity.  The  oil  may  be  ea- 
sily freed  from  any  water  that  may  hap- 
pen to  be  pressed  out  with  it,  as  a  sponta- 
neous separation  between  them  will  take 
place  on  standing  for  sometime. 

For  the  encouragement  of  those  who 
may  choose  to  improve  this  subject,  it 
may  be  proper  to  observe,  that  all  the 
oils,  from  whatever  vegetable  substances 
they  are  drawn,  when  obtained  by  expres- 
sion with  due  caution,  agree  in  their  gene- 
ral qualities,  and  are  constantly  mild, 
even  though  they  are  obtained  from  very 
acrid  substances.  Thus  the  expressed 
oil  of  mustard  seed  is,  when  fresh,  as 
mild  as  that  of  olives,  and  the  bitter  al- 
mond, or  peach  kernel,  affords  an  oil,  by 
expression,  as  mild  as  that  of  sweet  al- 
monds It  is  upon  this  principle,  that  the 
sun-flower  oil  may  prove  equally  valua- 
ble with  the  best  Florence  oil,  for  diet 
or  medicine.  For  every  expressed  oil, 
when  pure  and  fresh,  is  void  of  acrimony, 
and  free  from  any  particular  taste  or 
smell. 

Besides  the  mild  oil  just  mentioned, 
some  substances  contain  another  kind  of 
oil,  called  their  essential  oil,  apart  of  which 
may  be  drawn  off  with  the  mild  expressed 
oil,  so  called,  and  impart  its  smell  or  taste 
to  that  oil.  It  is  called  essential  oii,  from 
its  yielding  the  particular  odour  of  the 
vegetable,  or  part  of  the  plant,  from 
which  it  was  obtained ;  it  is  pungent  to 
the  taste,  and  soluble  in  spirits  of  wine, 
which  the  other  is  not.  They  may,  there- 
fore, be  easily  distinguished  from  each 
other. 

The  oil  of  sweet  almonds,  and  the  oil 
of  olives,  being  pure  unctuous  expressed 
oils,  not  soluble  in  spirits  of  wine,  but 


OIL 


OIL 


mild  to  the  taste,  and  void  of  odour,  very 
soft,  emollient,  and  lenitive,  are  chiefly 
used  in  medicine  and  diet.  And  the  rea- 
son why  the  oil  of  olives,  in  particular,  is 
preferred,  is  because  it  is  less  expensive, 
and  will  keep  a  much  longer  time  without 
becoming  rancid. 

Perhaps,  on  trial,  the  sun-flower  seeds 
may  be  found  10  contain  an  oil  that  will 
answer  the  like  good  purposes  with  the 
sa.lad  and  medicinal  oil  now  in  use.  If 
so,  it  will  have  this  advantage  over  that  of 
almonds  or  olives,  that  it  is  a  native  of 
the  country,  may  be  always  had  fresh, 
and  at  a  small  expense  Whereas  the 
others  are  the  produce  of  distant  coun- 
tries, bear  a  high  price,  and  are  often 
adulterated  on  that  account;  or,  being 
kept  a  long  time,  they  lose  their  mild  qua- 
lity, and  become  rancid  and  acrimonious. 

The  praciicableness  of  getting  oil  a- 
mong  ourselves  at  a  moderate  expense, 
and  the  importance  of  using  it  fresh,  to- 
gether with  the  probable  uses  of  sun- 
flower oil  for  varnishes,  for  the  basis  of 
ointments,  and  for  mixing  of  paints,  as 
well  as  other  purposes  to  be  answered  by 


have  the  press  well  cleaned,  so  as  to  leave 
no  tincture  from  what  may  have  been  al- 
ready pressed ;  in  my  opinion,  this  is  an 
article  of  consequence,  and  1  believe  it 
will  grow  in  Philadelphia.  The  way  to 
sow  it  is  in  holes  about  three  feet  asun- 
der, dropping  in  each  hole  about  ten 
grains;  when  it  comes  up,  thin  it  to  three 
or  four  of  the  most  promising  :  the  seeds 
will  appear  in  pods  about  September,  and 
should,  when  full  grown,  and  before  dry, 
be  gathered  in.  The  method  is  as  fol- 
lows :  As  soon  as  you  perceive  about 
three-fourths,  or  four-fifths,  of  the  pods 
rise  on  the  stalk,  and  the  lower  pods  be- 
gin to  loose  their  seeds,  it  is  then  time  to 
take  it  in  ;  for  after  that,  as  much  as  ripens 
one  day  at  top,  so  much  falls  out  of  the 
pod  ai  bottom.  You  take  a  sharp  hatchet- 
bill,  or  some  such  weapon,  and  with  it  cut 
off  the  stock  twelve  to  eighteen  inches  be- 
low any  of  the  seed,  holding  the  stock 
with  the  left  hand,  and  when  cut,  a  se- 
cond person  receives  it,  keeping  it  up- 
right, till  he  has  his  load ;  for  if  you  turn 
it  downwards,  the  ripe  seed  will  fall  out 
of  i he  pods.  You  may  immediately  carry- 
oils  in  general,  claim  our  attention  to  this  !  it  into  a  barn,  and  set  it  upright  on  a  close 
subject,  and  encourage  further  trials  of  (  floor,  till  you  perceive  all  the  pods  fully 


the  like  kind 

Before  we  quit  this  subject,  it  may  not 
be  amiss  t  mention,  that  castor  oil  is  jnst- 
lv  celebrated  for  its  medicinal  qualities. 
The  plant,  from  the  seeds  of  which  it  is 
got,  may  be  easily  cultivated  in  this  coun- 
try, and  the  increase  of  it  is  very  great  in 
a  short  time  ;  iDtigih*  it  not  then  be  worth 
the  attention  of  our  farmers  to  propagate 
this  plant  for  the  sake  of  its  oil  ?  We 
would  just  suggest,  that  perhaps  it  might 
be  worth  while  to  try  whether  the  seeds 
of  sumach,  with  which  this  country 
abounds,  or  of  the  mullein,  which  grows 
in  old  fields,  and  bears  a  gre..t  quantity  of 
seed,  would  not  yieid  by  expression,  a 
va.uable  oil  for  medicine  or  other  pur- 
poses. 

Bene  seed  Oil. 
On  the  subject  of  the  bene  seed  oil,  the 
following  letter  of  Mr.  John  Morel  to  Mr. 
Charies  Thompson,  secretary  of  the  Ame- 
rican Philosophical  Society,  at  Philadel- 
phia, dated  Savannah,  May  5,  1769,  may 
be  useful. 

Si  1  send  you  a  small  keg  of  bene,  or 
bene  seed,  which  you  will  please  to  pre- 
sent to  your  Society  for  their  inspection. 
This  seed  makes  oil  equal  in  quality  to 
Florence,  and  some  say  preferable.  Some 
say  one  hundred  weight  of  seed  will  pro- 
duce ninety  pounds  of  oil,  others  say  less ; 
be  that  as  it  will,  it  certainly  makes  very 
fine  oil,  .uid  produces  amazingly.  If  it  is 
put  to  the  trial,  care  should  be  taken  to 


dry  and  open ;  (you  may,  if  you  choose, 
leave  it  in  the  field,  which  must  be  the 
case,  if  a  large  quantity  is  planted,)  then 
thresh  it,  and  run  it  through  a  proper 
sieve,  and  it  is  fit  for  use. 

We  are  quite  unacquainted  with  the  me- 
thod of  expressing  the  oil,  but  we  believe  if 
it  is  designed  for  lable  use,  nothing  should 
be  done  to  the  seed,  as  it  might  give  it  an 
ill  taste.  The  lighter  and  drier  the  soil 
is  in  which  it  is  planted,  the  better. 

Vegetable,  Essential,  or  Volatile  Oils. 
These  oils  are  so  called,  because  they 
are  evaporable,  at  a  moderate  heat,  with- 
out decomposition,  and  because  in  them 
the  odour  or  fragrance,  or  as  it  was  call- 
ed by  the  old  chemists,  the  essence  of  ve- 
getables resides.  They  are  not  confined 
to  any  particular  parts  of  a  plant,  but  ex- 
ist in  minute  cells  distributed  through  the 
root,  the  wood,  the  bark,  the  leaves,  the 
blossoms,  and  seeds.  The  part  in  which 
they  occur  less  frequently  than  any  other, 
is  the  lobe  or  cotyledon  of  the  seed,  the 
peculiar  seat  of  the  fixed  oil,  while  the 
husk  or  cover  of  the  seed  is  always  more 
or  less  impregnated  with  volatile  oil,  the 
acrimony  of  which  defends,  in  some  de- 
gree, the  rudiments  of  the  young  plant 
from  the  depredation  of  insects. 

The  method  of  extracting  the  volatile 
oil  differs,  for  the  most  part,  very  mate- 
rially from  those  which  we  ave  already 
described,  as  practised  for  the  fixed  oils. 


OIL 


OIL 


Those  which  are  procured  from  the  rinds 
of  the  lemon,  the  orange,  and  the  berga- 
motte  orange,  are  the  only  ones  capable 
of  being  obtained  by  expression,  which  is 
performed  in  the  following  manner.  A 
small  wheel,  with  its  circumference  set 
with  short  nails,  is  put  in  motion,  and  a 
lemon  or  orange  is  applied  to  it  till  the 
whole  of  the  yellow  outer  rind  is  thus 
rasped  away  :  the  raspings  fall  to  the  bot- 
tom of  the  case  in  which  the  wheel  turns, 
and  when  a  sufficient  quantity  is  collect- 
ed, are  squeezed  between  two  plates  of 
glass ;  by  this  gentle  pressure  the  essen- 
tial oil  flows  from  the  ruptured  cells  into 
any  convenient  vessel  placed  to  receive  it, 
and  undergoes  no  further  preparation,  ex- 
cept that  of  being  allowed  to  rest  till  the 
water  and  other  impurities  have  subsided. 

A  method  analogous  to  that  by  which 
the  vegetable  butters  are  obtained,  is 
sometimes  practised  in  India  for  procuring 
that  delicious  and  costly  perfume,  the  it- 
tur  of  roses.  For  this  purpose  a  clean 
cask,  or  large  glazed  earthen  jar,  is  filled 
with  rose  leaves  carefully  separated  from 
the  calyces,  and  spring  water  poured  on 
just  sufficient  to  cover  them  :  the  vessel, 
with  its  contents,  is  then  set  in  the  sun  for 
two  or  three  days,  and  taken  under  cover 
during  the  night.  At  the  end  of  the  third 
or  fourth  day  small  particles  of  yellow  oil 
will  be  seen  floating  on  the  surface  of  the 
water,  which,  in  the  course  of  a  week,  will 
have  increased  to  a  thin  scum  :  this  is 
taken  up  by  a  little  cotton  tied  to  the  end 
of  a  stick,  and  squeezed  into  a  small  vial. 

The  oil  contained  in  the  fragrant  blos- 
soms of  those  plants  whicu  have  none  in 
their  other  parts,  as  the  violet,  the  migno- 
nette, the  jasmine,  the  tuberose,  the  hya- 
cinth, and  all  the  scented  liliaceous  plants, 
&c.  although  exceedingly  odorous,  is  so 
minute  in  quantity,  and  so  easily  destroy- 
ed by  heat,  as  to  be  incapable  of  being  ex- 
tracted in  any  other  way  than  by  means 
of  the  oil  of  bene,  as  described  in  the  last 
article.  The  fragrant  oil  may  afterwards 
be  separated  from  the  oil  of  bene  in  the 
following  manner.  Let  a  vial  be  half  filled 
with  a  mixture  of  alcohol,  and  perfumed 
oil,  in  equal  proportions,  and  shaken  for 
a  few  minutes,  that  every  particle  of  each 
may  come  in  contact  with  the  other  :  then 
pour  off  the  alcohol  from  the  oil,  which 
will  be  found  to  be  nearly  inodorous,  hav- 
ing yielded  its  essential  oil  to  the  alcohol. 
Let  this  perfumed  spirit  be  shaken  again, 
with  successive  portions  of  oil,  till  the 
richness  of  its  fragrance  is  not  sensibly 
increased,  and  then  pour  it  into  a  bason 
containing  two  or  three  times  its  bulk  of 
pure  water:  the  water  and  alcohol  will 
combine  together,  and  the  greater  part  of 


the  essential  oil  will  be  liberated,  and  will 
float  at  the  top  of  the  liquor,  from  which 
it  may  be  skimmed  oft  by  means  of  a  little 
cotton.  The  liquor  being  afterwards  sub- 
mitted to  very  gentle  distillation,  the  first 
portion  of  spirit  that  comes  over  will  be 
found  to  be  still  very  fragrant,  and  may 
be  employed,  mixed  with  f  esh  alcohol,  in 
treating  other  portions  of  scented  oil. 

By  far  the  greater  number,  however,  of 
essential  oils  are  obtained  by  dhect  distil- 
lation. If  the  substance  to  be  treated  is 
a  fresh  herbaceous  plant,  it  requires  no 
previous  treatment ;  but  if  it  is  a  dried 
plant,  a  few  hours  maceration  in  water  is 
advisable  ;  if  a  bark  or  wood  is  to  be  dis- 
tilled, it  must  be  rasped  or  cut  into  sha- 
vings, and  macerated  for  several  days  ; 
this  being  done,  a  tinned  copper  still,  or 
alembic  is  to  be  charged  with  the  solid 
matt-rials  ciosely  rammed  down,  on  which 
is  to  be  poured  just  water  enough  to  cover 
them  ;  the  head  being  then  luted  on,  and 
the  refrigeratory  filled  with  cold  water, 
the  fire  must  be  lighted,  and  so  regulated 
as  to  keep  the  contents  of  the  still  con- 
stantly simmering,  but  scarcely  boiling. 
The  steam  being  condensed  in  the  worm 
wiU  form  a  small  stream  of  water,  and  is 
to  be  collected  in  proper  vessels  till  it 
comes  off  nearly  insipid  and  inodorous, 
when  the  distillation  is  to  be  stopped.  The 
first  part  of  the  produce,  being  turbid 
from  supersaturation  with  essential  oil,  is 
to  be  kept  for  some  hours  in  a  cold  place, 
during  which  time  the  excess  of  oil  will 
separate  from  the  water,  and  either  float 
on  its  surface,  or  sink  to  the  bottom,  ac- 
cording to  its  specific  gravity.  The  com- 
plete separation  of  the  oil  from  the  distill- 
ed water  is  effected  by  a  very  simple  in- 
strument called  the  Italian  recipient,  and 
the  whole  of  the  water  drawn  oft  in  the 
first  distillation  is  to  be  employed,  as  far 
as  it  will  go,  in  the  next,  instead  of  plain 
water,  by  v»  hich  it  is  manifest,  that  the 
produce  of  oil  in  the  second  distillation 
will  exceed  that  of  the  first,  (other  cir- 
cumstances being  equal)  by  all  the  quan- 
tity held  in  permanent  solution  by  the  wa- 
ter of  the  former  process.  Hence  it  is 
manifest,  that  by  this  mode  of  proceeding, 
the  amount  of  oil  yielded  by  equal  quan- 
tities of  the  same  substance,  will  form  a 
constantly  increasing  series,  till  the  whole 
of  the  water  drawn  off  by  each  distillation 
is  completely  saturated  with  oil.  This  ac- 
counts, in  some  degree,  for  the  great  dif- 
ference in  the  proportions  of  oil  obtained 
by  different  chemists  from  the  same 
plants  ;  for  as  Bindheim  has  satisfactorily 
shewn,  it  is  not  till  the  seventh,  or  even, 
in  some  cases,  the  tenth  distillation,  that 
the  produce  of  oil  attains  its  maximum. 


OIL 


OIL 


ft  is  not  only  from  the  odorous  vegeta- 
bles themselves  that  essential  oil  may  be 
procured,- but  also  from  such  of  ihe  im- 
mediate products  of  vegetation  as  possess 
any  odour;  such  are  the  balsams,  and 
many  of  the  resins  and  gum  resins.  The 
process  to  be  followed  is  distillation  with 
water,  and  precisely  the  same  subsequent 
treatment  as  we  have  already  described. 

The  peculiar  odour  of  vegetables,  when 
not  in  a  state  of  decomposition,  depend- 
ing on  the  volatile  oil  that  they  contain,  it 
will  be  obvious  that  the  odours  of  the  oils 
themselves  must  be  equally  various,  and 
therefore  incapable  of  being  described 
The  taste  of  all  of  them  is  exceedingly 
hot  and  pungent,  but  in  some,  particular- 
ly the  oil  of  peppermint,  is  followed  by  a 
remarkable  sensation  of  coldness :  this, 
however,  is  merely  a  nervous  sensation, 
the  thermometrical  temperature  under- 
going no  change.  The  acrimony  of  some 
of  the  oils,  as  the  oil  of  cloves,  is  so  great 
as  actually  to  destroy  the  outer  skin  of 
the  tongue  and  of  other  sensible  parts. 
The  consistence  of  the  essential  oils  is 
very  various ;  some  being  as  limpid  as 
water,  while  others  are  thick  and  gluti- 
nous, like  the  expressed  oils-  A  slight 
degree  of  cold  is  sufficient  for  their  con- 
gelation, at  which  time  they  assume  the 
appearance  of  crystalline  plates,  which, 
however,  must  not  be  confounded  with 
the  prismatic  crystals  that  most  of  them 
deposit  by  long  exposure  to  the  air.  The 
colours  of  essential  oils  are  various,  some 
are  blue,  others  green,  but  the  usual  co- 
lour is  light  yellow,  verging  more  or  less, 
by  long  keeping,  to  reddish  brown. 

Essential  oil  is  completely  volatile  with- 
out decomposition  at  a  heat  less  than  that 
of  boiling  water ;  (hence  if  a  few  drops 
are  spread  on  a  piece  of  paper,  and  then 
held  for  a  minute  or  two  before  the  fire, 
any  sophistication  with  expressed  oil  may 
be  detected  by  the  grease  spot  that  will 
remain  after  the  volatile  oil  has  been  en- 
tirely exhaled).  It  may,  however  be  de- 
tained in  a  higher  heat  by  mechanical 
mixture  with  dry  clay  or  sand  and  then 
it  undergoes  a  partial  decomposition,  car- 
buretted  hydrogen  being  given  out,  and  a 


little  charcoal  remaining  in  the  receiver  : 
the  undecomposed  residue,  if  subjected 
three  or  four  times  successively  to  similar 
treatment,  will  be  entirely  destroyed. 

Essential  oils  are  highly  combustible ; 
they  take  fire  on  the  application  of  an  ig- 
nited body,  or  by  the  electric  spark,  and 
burn  with  a  lartre  white  flame  and  a  dense, 
black  smoke  ;  a  larger  proportion  of  oxy- 
gen is  required  for  their  combustion  than 
of  the  other  oils,  and  a  greater  quantity  of 
water  is  produced. 

Oil,  that  by  long  keeping  in  a  half-closed 
bottle  has  become  thick  and  nearly  scent- 
less, may  be  rectified  by  re-distilling  it 
with  water,  and  some  of  the  fresh  vegeta- 
ble from  which  it  was  u'iginally  extract- 
ed ;  and  this  was  often  citea  as  a  proof 
that  the  substances  called  essential  oils, 
were,  in  reality,  compounds  of  resin  and 
the  spiritus  rector^  or  aromatic  principle. 
But  precisely  the  same  effect  may  be  pro- 
duced by  means  of  alcohol,  or  still  more 
readily  by  ether.  This  curious  and  im- 
portant fact  was  first  stated  by  De  Roover, 
from  whose  experiments  it  appears,  that 
if  thick  spoiled  oil  be  mixed  with  one- 
sixteenth  of  sulphuric  ether  for  a  few  days, 
and  then  distilled  with  pure  water,  more 
than  half  the  oil  will  come  over  perfectly 
limpid  and  possessed  of  its  peculiar  odour, 
t  while  the  remainder  will  be  left  behind  in 
the  still  in  the  state  of  a  dark  coloured 
resin.  The  united  weights  of  the  distilled 
oil  and  resin  exceed  that  of  the  original 
oil,  whence  it  is  probable  that  the  ether 
actually  combines  with  part  of  the  oil,  and 
probably  by  supplying  it  with  hydrogen, 
restores  to  it  the  liquidity  and  odour  which 
it  possessed  at  first.  It  is  to  be  regretted 
that  M.  de  R.  did  not  follow  up  his  expe- 
riments by  treating  the  resinous  portion 
with  fresh  quantities  of  ether,  so  as  to  as- 
certain whether  it  was  possible  to  convert 
it  in  part,  or  entirely,  into  volatile  oil  as  at 
first. 

Essential  oil  is  sparingly  soluble  in  wa- 
ter, from  which  it  may  be  separated  by 
distillation,  but  is  taken  up  much  more 
abundantly  by  alcohol ;  this  solution,  how- 
ever, is  decomposable  by  water,  the  great- 
est part  of  the  oil  being  separated. 


OIL 


OIL 


TABLE. 

Exhibiting  the  Quantity  of  Volatile  Oil  obtained  from  different 

Vegetables. 


JYiQTnC  OJ  trie  V Cg€t(lul€. 

hgii  ciii  1 1  ty  * 

TJ'pjcrlit        th*  fit/ 

Maker  of  the 
Experiment. 

Agallochum  wood 



10  lb 

4  drachms 

Hoffmann 

Angelica  root 

i  ib 

1  drachm 

Cartheuser 

Aniseed 

Assafoetida  - 

i  ib 

4  ounces 

2  drachms  ") 
1  drachm  3 

Neumann 

Balm,  common  ... 

6  baskets 

1  drachm 

 Turkey 

ditto 

2  ounces  C 

Dehne 

Cajeptit  seeds 

1  lb 

15  grains  j 

Calamus  aromaticus 

50  lb 

2  ounces 

Hoffman  n 



1  lb 

2  scruples 

Neumann. 

Camomile  flowers,  common 

1  lb 

1-2  drachm 

Cartheuser 

 L_ 

6  1b 

5  drachms 

Lewis 



200  baskets 

1  lb 

Dehne 

Camomile  flowers,  wild 

1  lb 

20  grains 

Cartheuser 



6  lb 

2  1-2  drachms 

Lewis 

 Roman 

30  lb 

1  3-4  ounces 

Dehne 

Caraway  seeds 

4  1b 

2  ounces  } 



2  lb 

9  drachms  C 

Lewis 

1  cwt 
1  ounce 

&3  ounces  j 

Cardamum  seeds 

1  scruple 

Neumann 

CariophilH  Plinii 
Carline  thistle  root 

1-2  lb 

1-2  ounce 

Dehne 

Mb 

2  1-2  scruples 

Neumann 

Carrot  seeds  ... 

2  lb 

1  1-2  drachm 

Lewis 

Cascarilla  bark 

1  lb 

*  drachm 

Cartheuser 



30  lb 

4  ounces 

Dehne 

Cassia  flowers  ... 

1  lb 

1-2  drachm 

Cartheuser 

30  lb 

4  ounces 

Dehne 

Cedar  wood 

1  lb 

2  drachms 

Margraff 

Chervil  leaves 

9  lb 

1-2  drachm 

Neumann 

Cinnamon 

1  lb 

1  drachm 

Sala 

— — ~  - 

1  lb 

2  1-2  scruples 

Neumann 



4  lb 

6  drachms 

Lemeri 

 .... 

 ... 

1  lb 
1  lb 

2  drachms  "> 
8  scruples  3 

Cartheuser 

3  lb 

4  drachms 

Dehne 

Clary  (garden),  the  seeds 

41b 

2  drachms  "> 

Lewis 

 in  flower,  fresh 

130  lb 

3  1-2  ounces  3 

Cloves  .... 

1  lb 

1  1-2  ounce 

Teichmeyer 

1  lb 

2  1-4  ounces 

Cartheuser 

2  lb 
21b 
1  lb 

5  ounces 
5  ounces 
1  oz..  6drach.  } 

Hoffmann 

lib 

2  1-2  ounces  C 

Dehne 

1  lb 

2  oz.  2  drach.  J 

Copaiba  balsam 

lib 

6  ounces 

Hoffmann 

lib 

8  ounces 

Lewis 

Culilabana  cortex 

1  lb 

1  drachm  "> 

Yogei 

Cummin  seed  - 

lib 

5  drachms  3 

1  bushel 

21  ounces 

Lewis 

Dill  seed  ... 

4  lb 

2  ounces  3 

 with  tiie  tops 

6  baskets 

8  ounces 

Dehne 

Dittany  of  Crete 

lib 

30  grains 

Lew's 

OIL 


OIL 


Parsley  seeds 

— —  leaves,  fresh 

 leaves,  with  the  seeds 

Parsnep  seeds 
Pennyroyal  in  flower,  fresh 
Pepper,  black 


Cartheuser 
Neumann 


Hoffmann 
Neumann 
Dehne 

Lewis 

Hoffmann 

Dehne 

Hoffmann 

Neumann 

Hoffmann 

Geoffroy 

Neumann 

Sala 

Cartheuser 

Lewis 

Dehne 

Lewis 
Gaubius 


OIL 


OIL 


Name  of  the  Vegetable. 


Quantity. 


Weight  of  the  Oil. 


Maker  of  the 
Experiment. 


Pepper,  black 


Jamaica 


Peppermint,  fresh 
Rhodium  wood 


Roses 


Rosemary,  in  flower 
 leaves 


—  fresh 

Rue  leaves 


in  flower 


 with  the  seeds 

Saffron,  Oriental 
Sage  leaves 

 in  flower,  fresh 

 of  virtue,  in  flower 

Sassafras  wood 


Savin  bark 


 wood  ... 

Saunders  yellow 

Scurvy  grass,  in  flower,  fresh 

Smallage  seeds 

Staechas,  in  flower,  fresh 

Thyme,  in  flower,  fresh 

 dry 

 (lemon)  in  flower,  fresh 


a  "little  dried 


Wormwood  leaves,  dry 
Zedoary  root 


1  lb 
1  lb 

1  ounce 
41b 
lib 
1  lb 
1  lb 
1  lb 
1  lb 
1  cwt 
1  cwt 
12  lb 
1  cwt 
1  lb 
1  lb 

3  1b 

1  lb 
70  lb 
10  lb 
10  lb 

4  1b 
60  lb 
72  1b 
lib 
34  lb 
27  lb 

lib 

61b 
6  lb 
30  lb 
24  lb 

2  1b 
29  lb 
32  lb 
Ub 

6  baskets 
Ub 

5  3-4  lb 

2  cwt 

3  1-2  lb 
51  lb 
98  lb 
104  lb 

4  lb 
18  lb 
1  lb 
71b 


2  1-2  drachms 
4  scruples 

30  grains 

3  drachms 
3  drachms 

2  drachms 

3  drachms 

3  drachms 

4  drachms 

4  drachms 

1  ounce 
30  grains 

8  ounces 

2  drachms 

3  drachms 

3  1-6  drachms 

1  drachm 

5  ounces 

2  drachms 

4  drachms 

1  drachm 

2  1-2  ounces 

3  ounces 

5  scruples 
1  1-2  ounce 

6  drachms 

1  1-2  drachm 

1  3-4  ounces 

2  ounces 

7  oz.  1  drach. 

9  ounces 

5  ounces 

9  ounces ' 
1-2  ounce 
2  drachms 

6  drachms 

10  grains 
2  drachms 

5  1-2  ounces 
1  1-2  drachm 

1  3-4  ounces 

2  1-2  ounces 

3  ounces 
1  ounce 

1  1-2  ounce 
1  drachm 
1  ounce 


} 


Neumann 

Cartheuser 

Neumann 

Lewis 

Neumann 

Sala 

Cartheuser 

Tachenius 
Homberg 
Hoffmann 
Lewis 

Sala 

Neumann 

Lewis 

Cartheuser 

Hoffmann 


Lewis 

Cartheuser 

Lewis 

Vogel 

Hoffmann 

Neumann 

Dehne 

Hoffmann 

Dehne 

Cartheuser 

Dehne 

Neumann 


Lewis 


Neumann 
Dehne 


VOL.  II. 


OIL 


OJL 


When  the  quantity  of  oil  inherent  in  any 
particular  substance  is  to  be  ascertained, 
it  cannot  be  done  directly  on  the  first  dis- 
tillation, unless  water  were  to  be  employ- 
ed for  this  purpose  that  is  already  impreg- 
nated with  oil ;  because  the  water  that  is 
distilled  from  an  oleaginous  body  for  the 
first  time  always  imbibes  a  considerable 
portion  of  its  volatile  oil,  and  thus  renders 
the  calculation  erroneous. 

Neither  are  vegetables  impregnated 
with  the  same  quantity  of  oil  at  all  sea- 
sons of  the  year :  but  herbs  should  be  ap- 
plied to  this  purpose  only  when  they  are 
in  full  blossom,  and  many  of  them  when 
they  are  run  to  seed.  The  roots  are  most 
impregnated  with  oil  just  before  they  send 
forth  their  radicles  in  the  spring,  but 
woods  at  the  beginning  of  the  winter. 
The  maceration  of  green  vegetables  is 
needless,  and  indeed  rather  detrimental 
than  otherwise :  whereas,  on  the  contrary, 
with  dry  and  solid  bodies  it  may  be  more 
useful,  in  which  case  some  common  salt 
is  added,  in  order  to  prevent  fermentation 
taking  place-  "When  fresh  vegetables  pos- 
sess no  particular  volatile  smell,  it  is  ra- 
ther of  use  to  let  them  wither  a  little.  Oils 
that  yield  a  volatile  odour  must  be  distill- 
ed over  with  a  gentle  beat ;  but,  on  the 
other  hand,  such  as  at  the  same  time  are 
distinguished  by  a  greater  specific  gravi- 
ty, require  a  somewhat  stronger  fire  for 
their  distillation. 

Most  volatile  oils,  it  is  true,  swim  upon 
the  water  with  which  they  have  come  over 
in  distillation ;  there  are  some,  however, 
that  sink  in  it.  The  method  of  separating 
the  former  is,  first  to  leave  the  glass  filled 
with  the  oily  water  at  rest  for  some  days, 
and  then,  by  shaking  it  gently,  to  bring 
the  oil  up  to  the  surface  of  the  water.  It 
may  then  be  taken  oft'  either  with  a  tea- 
spoon, or  with  a  small  glass  syringe.  The 
best  method,  however,  is  to  convey  it  by 
means  of  a  short  and  slender  skein  of  cot- 
ton, from  the  glass  in  which  it  is  first  re- 
ceived, into  another  glass  tied  to  the  up- 
per part  of  this,  by  which  means,  at  the 
same  time,  all  the  impurities,  which  are 
frequently  to  be  found  in  these  oils,  ad- 
here to  the  cotton,  and  the  oil  is  obtained 
pure  and  clear.  With  respect  to  the 
other  species  of  these  oils,  which  sink  to 
the  bottom  in  water,  and  are  consequent- 
ly heavier  than  water,  this  latter  fluid 
must  be  made  heavier  by  another  body  ; 
for  which  purpose,  nothing  more  is  neces- 
sary to  be  done,  than  to  impregnate  the 
Avater  strongly  with  common  salt,  till  the 
oil  which  lies  at  the  bottom  of  the  vessel 
rises  to  the  surface,  whence  it  may  then 
he  separated  in  the  manner  above  men- 
tioned. 


OILS,  Vegetable  Empyreumatic. 
Almost  every  vegetable  matter  when  sub- 
jected to  dry  distillation,  affords  a  quan- 
tity of  oil,  varying  according  to  the  nature 
of  the  substance,  and  the  circumstances 
of  the  experiment.  The  oil,  thus  produc- 
ed, has  not  been  subjected  to  very  accu- 
rate examination,  yet  may  be  described, 
as  possessing  the  following  characters. 
Its  colour  is  yellowish-red,  passing  into 
blackish-red,  it  has  a  strong  odour,  and 
an  acrid  empyreumatic  taste ;  it  is  more 
volatile  than  the  fixed  oils,  but  less  so 
than  the  proper  essential  ones  :  by  re-dis- 
tillation with  a  little  water,  it  comes  over 
nearly  colourless,  and  more  volatile  than 
before,  though  still  possessed  of  much 
of  its  empyreumatic  flavour.  Two  of 
these  oils,  namely,  tar  and  birch  oil,  are 
of  considerable  importance ;  for  an  ac- 
count of  the  first,  we  shall  refer  the  reader 
to  the  article  Turpentine.  The  latter 
is  prepared  in  Russia,  by  charring  birch 
wood  in  a  close  oven,  the  watery  acid  and 
oil  are  collected  in  a  large  receiver,  and 
the  latter  product  being  the  lightest,  is 
skimmed  off  from  the  surface  of  the  wa- 
ter. This  oil  has  a  peculiar  scent,  and  is 
said  to  drive  away  worms  and  other  in- 
sects, on  which  account,  it  is  used  in  the 
dressing  of  Russia  leather,  to  which  it 
communicates  those  properties,  that  ren- 
der it  so  much  esteemed  by  the  binders 
of  books. 

OILS,  Animal,  Fixed.--A11  animals 
except  those  included  in  the  class  of  in  - 
sects, contain  oil;  the  quantity  however 
of  which,  as  well  as  the  situation  which 
it  principally  occupies  in  the  body,  is  sub- 
ject to  considerable  variety.  In  all  cases 
it  is  contained  in  peculiar  receptacles,  of 
cellular  membrane;  but  these  receptacles 
in  quadrupeds  are  for  the  most  part  but 
sparingly  dispersed,  among  the  muscular 
fibre,  are  more  abundant  in  the  bones, 
and  most  so  of  all,  in  the  cavity  of  the  ab- 
domen, and  especially  attached  to  the 
kidneys.  The  hog  however  is  an  excep- 
tion to  tins,  the  principal  part  of  his  fat, 
being  deposited  between  the  skin  and  the 
muscles.  In  birds,  the  chief  seat  of  the 
oil,  is  immediately  below  the  skin,  and  in 
water-fowl,  it  is  completely  secreted  by  a 
collection  of  glands  in  the  rump.  In  the 
warm  blooded  fish,  as  the  whale,  the  oil 
is  chiefly  contained  in  the  head  and  jaw- 
bones, and  is  interposed  in  vast  abun- 
dance, between  the  skin  and  the  muscu- 
lar flesh.  In  the  cold  blooded  fish,  it  is 
contained  in  the  liver,  as  in  the  shark,  the 
cod,  and  the  ling  ;  or  is  dispersed  through 
the  whole  body,  as  in  the  sprat,  the  her- 
ring, and  pilchard. 

While  the  fat  remains  in  the  living  bo- 


OIL 


OIL 


dy,  i  always  in  a  fluid  or  semi-fluid 
state,  but  after  it  has  been  extracted,  and 
is  exposed  to  the  common  temperature,  a 
remarkable  difference  in  its  consistence 
is  observed.  The  oil  or  fat  investing-  the 
kidneys  of  quadrupeds,  is  called  suet  or 
tallow,  and  is  the  most  solid  and  hardest 
of  any  ;  the  next  in  hardness,  is  the  fat  of 
the  bones,  and  that  in  which  the  muscles 
are  imbedded,  is  the  next  in  degree ;  the 
fat  of  the  hog-,  (called  lard)  is  the  least 
solid.  The  fat  of  birds  is  seldom  so  solid 
us  hog's  lard,  and  in  many  species,  is  ac- 
tually fluid.  The  fat  or  oil  of  fish,  is  al- 
most always  fluid,  at  the  common  tempe- 
rature. Besides  the  above  varieties  of 
animal  oil,  there  is  yet  another  contained 
in  the  yolk  of  eggs,  and  which  may  be  ex- 
tracted by  simple  pressure,  after  the  yolk 
has  been  coagulated  by  heat. 

Animal  oil  in  its  purest  state,  is  obtain- 
ed by  cutting-  fresh  suet  into  shreds,  and 
liquefying-  it  into  boiling-  water,  and  then 
passing  it  through  a  piece  of  thin  gauze, 
in  order  to  separate  the  cellular  mem- 
brane. When  thus  purified,  it  is  of  a  yel- 
lowish-white colour,  moderately  hard,  of 
a  mild  taste,  and  nearly  destitute  of  odour 
or  flavour :  it  is  combustible,  like  the 
fixed  vegetable  oils,  and  agrees  also  with 
these  in  the  changes  produced  upon  it,  by 
the  alkalies  and  other  chemical  re-agents 
All  the  animal  oils,  however,  belong  to 
the  class  of  unctuous  or  fat  oils,  none  of 
them  being  either  drying  in  itself,  or  ca- 
pable of  becoming  so,  by  means  of  litharge 
or  other  substances. 

In  the  year  1798,  a  patent  was  granted 
to  Mr.  Collier,  for  a  chemical  process,  for 
freeing  fish-oils  from  their  impurities,  in 
point  of  smell,  taste  and  colour  j  and  also 
for  improved  strainers,  for  oils  and  other 
liquids,  &c.  The  whole  is  performed  in 
the  following  manner  :  first,  the  patentee 
pours  any  quantity  of  fish-oil,  or  a  mix- 
ture of  different  kinds  of  oil,  into  a  vessel, 
which  is  heated  to  the  temperature  of  110 
or  120  degrees  of  Fahrenheit's  thermome- 
ter; when  a  portion  of  caustic  mineral 
alkali  is  added,  the  weight  of  which  is 
equal  to  four  parts  to  the  hundred  of  the 
oil.  The  mixture  is  next  agitated  j  and 
after  the  sediment  and  salt  have  subsided, 
it  is  drawn  off  into  another  vessel,  con- 
taining a  sufficient  quantity  of  finely  pul-1 
verised,  fresh-burnt  charcoal,  and  a  small  i 
proportion  of  diluted  sulphuric  acid.  The 
agitation  is  repeated;  and,  when  the  coal, 


together  with  the  saline  and  aqueous  par- 
ticles, have  subsided,  the  oil  is  passed 
through  certain  strainers,  and  thus  ren- 
dered perfectly  transparent,  and  fit  for 
use.  Such  is  the  patentee's  process  ;  but 
as  a  description  of  the  vessels  employed, 
in  edulcorating  oil,  would  be  unintelligi- 
ble, without  the  aid  of  an  engraving,  the 
reader  will  consult  the  10th  volume  of  the 
Repertory  of  Jlrts,  8cc. ;  where  the  patent 
is  fully  described,  and  illustrated  with  a 
plate. 

In  April,  1792,  a  patent  was  granted  to 
Mr.  Charles  Gower,for  his  method  of  de- 
purating and  improving  animal  oil  He 
directs  equal  quantities  of  oil,  and  of  wa- 
ter previously  acidulated  with  a  due  pro- 
portion of  vitriolic  acid,  to  be  poured  into 
a  barrel  or  other  vessel,  which  must  be 
placed  near  a  fire,  and  briskly  agitated,  in 
order  to  unite  the  two  fluids  The  liquor 
is  then  passed  into  pans,  with  a  view  to 
complete  the  solution  of  the  gelatinous 
parts  ;  and  that  the  water  may  sink  to  the 
bottom  ;  when  the  clear  oil  is  decanted. 
Should,  however,  the  oil  intended  to  be 
purified,  have  a  turbid,  or  ropy  appearance, 
the  patentee  directs  equal  parts  of  such 
liquid  and  pure  water,  to  be  mixed  with 
a  little  yeast,  and  shaken  in  the  manner 
above-mentioned.  When  the  fermentation 
ceases,  the  whole  must  be  poured  into  si- 
milar pans,  where  all  feculent  particles 
will  subside,  and  the  oil  float  on  the  sur- 
face, whence  it  may  be  drawn  off  for 
use. 

Besides  its  utility  for  lamps,  animal  oil 
possesses  a  valuable  property,  which  de- 
serves attention.  If  one  drop  be  laid  on  a 
bug,  fly,  wasp,  or  earwig-,  it  will  cause 
the  immediate  death  of  those  troublesome 
vermin  ;  and,  even  when  it  is  damaged,  i 
may,  according  to  Mr.  Bucknall,  be  ad- 
vantageously applied  to  fruit  trees,  about 
a  month  after  they  have  been  washed 
with  soap-suds,  in  order  to  eradicate 
moss. 

Vegetable  oils  are  procured  either  by 
expression,  infusion,  or  distillation. 

Serious  accidents  frequently  occur  from 
vessels  containing  oil  and  other  inflamma- 
ble fluids  boiling  over,  and  setting  fire  to 
the  surrounding  buildings.  To  prevent 
these,  the  following  form  of  a  vessel,  has 
been  recommended  by  the  late  T.  P 
Smith,  in  the  Transactions  of  the  Ameri 
can  Philosophical  Society :  vol.  4. 


OIL 


OWL 


Let  ABCD, represent  a  large  Kettle ; 
DE,a  spout  running  out  to  the  distance 
of  three  or  four  feet,  commencing  at  D, 
four  or  five  inches  from  the  brim  of  the 
kettle,  and  the  termination  of  it  E,  just  as 
high  as  the  brim,  C.  Let  the  bottom  of 
this  spout  be  covered  with  wet  sponges, 
or  rags.  Now,  suppose  the  kettle  to  be 
filled  "up  to  D,  with  any  fluid,  then  as  soon 
as  it  commenced  boiling,  it  would  rise  in 
the  kettle,  and  in  rising  but  a  small  per- 
pendicular height,  would  pass  a  consider- 
able distance  up  the  spout  D  E  ;  here  the 
liquor  would  soon  cool,  and  of  conse- 
quence fall  back  into  the  kettle,  and  the 
whole  subside  to  its  original  height.  This 
would  occur  as  often  as  the  fluid  rose 
above  D,  as  the  evaporation  from  the  wet 
sponges  or  rags,  would  keep  D  E  con- 
stantly cool.  It  would  perhaps  be  best 
to  pass  the  spout,  through  the  side  of  the 
building  into  the  open  air,  as  thereby  the 
evaporation  would  be  increased,  and  con- 
sequently the  spout  kept  at  a  lower  tem- 
perature ;  in  this  case  it  might  be  co- 
vered. 

In  case  of  the  fluid  to  be  boiled  possess- 
ing a  very  strong  elective  attraction  to 
caloric,  (matter  of  heat,)  the  spout  may 
be  extended  to  the  width  of  the  diameter 
of  the  kettle,  or  a  projecting  shelf  might 
be  formed  all  around  it,  lined  below  with 
wet  sponges  or  rags. 

Animal  oils,  are  substances  of  great 
economical  importance.  They  are  used 
as  food,  and  in  medicine,  as  the  base  of  va- 
rious unguents:  they  are  largely  employed 
in  the  manufacture  of  soap,  and  for  burn- 
ing either  in  lamps,  or  in  the  form  of  can- 
dles. 

OIL,  Animal,  Volatile,  or  Dip- 
pel's  oil.— As  in  the  vegetable  kingdom, 


oil  is  produced  by  the  destructive  distil- 
lation of  various  substances,  that  contain 
none  in  their  natural  state  ;  so  it  is  with 
respect  to  the  animal  kingdom.  If  albu- 
men, or  gluten  be  distilled  at  a  dry  heat, 
there  arises  together  with  the  ammonia, 
and  carburetted  hydrogen,  a  quantity  of 
fetid  black  oil ;  this  was  made  the  sub- 
ject of  various  experiments,  first  by  Dip- 
pel,  a  chemist  of  Berlin,  and  afterwards  by 
Rouelle.  From  the  concurrent  labours  of 
these  enquirers  it  appears,  that  if  this  oil 
is  rectified  by  three  successive  distillations 
from  the  surface  of  the  water,  or  by  a 
greater  number  without  water,  it  becomes 
at  length,  quite  colourless  and  transpa- 
rent ;  it  has  a  powerful,  but  somewhat 
aromatic  odour,  and  is  nearly  as  light  and 
volatile  as  ether.  It  contains  a  little  am- 
monia, and  hence  changes  the  colour  of 
syrup  of  violets,  green  ;  it  is  sparingly  so- 
luble in  water,  and  largely  so  in  oils,  ether, 
and  alcohol.  It  combines  both  with  acids 
and  alkalies,  into  imperfect  soaps ;  it  is 
very  inflammable,  and  like  the  vegetable 
essential  oils,  may  be  set  on  fire  by  strong 
nitrous  acid.  If  exposed  to  the  light,  it  is 
partly  decomposed,  losing  its  transparen- 
cy, and  becoming  of  a  brown  colour.  It 
was  formerly  employed  in  medicine,  but 
is  now  wholly  disused. 

OIL  Mineral,  or  Petroleum.  See 
Bitumen. 

OIL  of  Vitriol.  See  Sulphuric 
Acid. 

OIL-COLOUR  CAKES.  The  greatest 
silver  Pallet  and  twenty  guineas  were 
voted  to  Mr.  Blackman,  for  discovering 
to  the  Society,  for  the  use  of  the  public, 
his  method  of  making  the  above  mention- 
ed cakes. 

Take  of  the  clearest  giim  mastich,  re- 


OPI 


OPI 


duced  to  fine  powder,  four  ounces ;  of 
spirit  of  turpentine,  one  pint ;  mix  them 
together  in  a  bottie,  stirring  them  fre- 
quently till  the  mastich  is  dissolved  ;  if  it 
is  wanted  in  haste,  some  heat  may  be  ap- 
plied, but  the  solution  is  best  when  made 
cold.  Let  the  colours  to  be  made  use  of, 
be  the  best  that  can  be  procured,  taking- 
care  that,  by  washing,  &c  they  are  brought 
to  the  greatest  degree  of  fineness  possi- 
ble. When  the  colours  are  dry,  grind 
them  on  a  hard  close  stone,  (porphyry  is 
the  best)  in  spirit  of  turpentine,  adding  a 
small  quantity  of  the  mastich  varnish.  Let 
the  colours  so  ground  become  again  dry ; 
then  prepare  the  composition  for  forming 
them  into  cakes,  in  the  following  manner. 
Procure  some  of  the  purest  and  whitest 
spermaceti,  you  can  obtain;  melt  it  over' 
a  gentle  fire,  in  a  clean  earthen  vessel ; 
when  fluid,  add  to  it  one-third  of  its  weight 
of  pure  poppy  oil,  and  stir  the  whole  to- 
gether ;  these  things  being  in  readiness, 
place  the  stone,  on  which  your  colours 
were  ground,  on  a  frame  or  support,  and, 
by  means  of  a  charcoal  fire  under  it,  make 
the  stone  warm  ;  "next  grind  your  colour 
fine  with  a  muller  ;  then,  adding  a  suffi- 
cient quantity  of  the  mixture  of  poppy 
oil,  and  spermaceti,  work  the  whole  to- 
gether with  a  muller,  to  a  proper  consist- 
ence ;  take  then  a  piece,  of  a  fit  size  for 
the  cake  you  intend  to  make,  roll  it  into  a 
ball,  put  it  into  a  mould,  press  it,  and  it 
will  be  complete. 

When  these  cakes  are  to  be  used,  they 
must  be  rubbed  down  in  poppy  or  othe»* 
oil,  or  in  a  mixture  of  spirit  of  turpentine 
and  oil,  as  may  best  suit  the  convenience 
or  intention  of  the  artist. 

N.  B.  It  may  be  proper  to  observe,  that 
Mr.  Blackmail's  colours  in  bladders,  are 
prepared  with  a  mixture  of  spermaceti, 
and  differ  from  his  cakes,  only  in  having  a 
larger  proportion  of  oil. 

At  the  end  of  the  foregoing  description, 
are  testimonies  from  Mr.  Cpsway,  Mr. 
Stothard,  and  Mr.  Abbot ;  stating  that 
Mr.  Blackman's  oil-colour  cakes,  work  as 
well  as  other  oil-colours  ;  that  their  dry- 
ing without  a  skin  upon  the  surface,  is  a 
great  advantage  ;  and  that  Mr.  Black - 
man's  invention  is,  upon  the  whole,  an  es- 
sential improvement  in  oil  painting. 

OIL,  OLIVE.    See  Oil. 

ONION.  See  Agriculture,  and 
Kitchen  Garden. 

OPIUM.  On  wounding  the  heads  or 
stalks  of  the  white  poppy,  a  milky  juice 
exudes  ;  which  exsiccated,  proves  a  fine 
kind  of  opium.  In  Natolia,  Cilicia,  Cap- 
padocia,  in  the  neighbourhood  of  Cairo, 
and  in  several  parts  of  the  Turkish  domi- 
nions, poppies  are  cultivated  for  this  use 


in  fields,  as  corn  among  us.  Tins  method 
of  collecting  the  juice  by  incision,  is  de- 
scribed by  Kaempfer,  in  his  Annrnitates 
Exoticae.  T,his  process,  however,  is  now 
but  rarely  practised,  the  consumption  of 
this  drug,  being  too  great  to  be  supplied 
by  that  method  of  collection.  The  best 
sort  of  the  officinal  opium,  is  the  express- 
ed juice  of  the  heads,  or  of  the  heads  and 
the  upper  part  of  the  stalks,  inspissated 
by  a  gentle  heat :  this  was  formerly  call- 
ed  meconium,  in  distinction  from  the  true 
opium,  or  juice  which  issues  spontane- 
ously. The  inferior  sorts,  (for  we  find 
considerable  differences,  in  the  quality  of 
this  drug,)  are  said  to  be  prepared  by 
boiling  the  plant  in  water,  and  evaporating 
the  strained  decoction ;  but  as  no  kind  of 
our  opium  will  totally  dissolve  in  water, 
the  juice  is  most  probably  extracted  by 
expression.  Neumann  was  informed,  by 
some  Turks  at  Genoa  and  Leghorn,  that 
in  some  places  the  heads, stalks,  and  leaves 
are  committed  to  the  press  together,  and 
this  juice  inspissated  afibrds  a  very  good 
opium. 

On  this  head  Dr.  Lewis  remarks,  that 
the  point  has  not  yet  been  fully  determin- 
ed. It  is  commonly  supposed,  that,  what- 
ever preparations  the  Turks  may  make, 
from  the  poppy  for  their  own  use,  the 
opium  brought  to  us,  is  really  the  milky 
juice,  collected  from  incisions  made  in  the 
heads,  as  described  by  Kaempfer.  It  is  cer- 
tain, that  an  extract  made  by  boiling  the 
heads,  or  the  heads  and  stalks,  in  water, 
is  much  weaker  than  opium  ;  but  it  ap- 
pears also,  that  the  pure  milky  tears  are 
considerably  stronger. 

The  principles  separable  from  opium, 
are,  a  resin,  gum,  a  minute  portion  of  sa- 
line matter,  water,  and  earth.  The  resin 
is  of  two  kinds  ;  one  more  truly  resinous, 
of  a  solid  consistence,  in  its  nature  more 
fixed,  and  its  operation  more  sluggish  ; 
the  other  softer  and  thinner,  more  volatile, 
and  of  much  more  speedy  and  powerful 
activity.  The  saline  matter  is  of  the  aci- 
dulous kind,  analogous  to  the  essential 
salts  of  other  vegetables  :  its  proportion 
is  so  small,  that  it  is  not  easily  separable 
in  its  proper  form,  though  it  has  some- 
times happened,  that  actual  crystals  have 
concreted  in  a  watery  solution  of  opium. 
The  resin,  the  gum,  and  the  salt,  arc  very 
intimately  combined  together,  insomuch 
that  all  the  three  dissolve  almost  equally 
in  water,  and  in  spirit  i  it  is  probably  to 
the  saline  principle  in  this  and  other  ve- 
getables, that  this  intimacy  of  union,  is  in 
great  measure  to  be  ascribed. 

Four  ounces  of  opium,  treated  with  ah 
i  cohol,  yielded  three  ounces  and  four  scru- 
I  pies  of  resinous  extract,  five  drachms  auti 


OPI 


OPI 


a  scruple  of  indissoluble  impurities  re- 
maining. On  taking-  four  ounces  more, 
and  applying  water  at  first,  Neumann  ob- 
tained two  ounces  five  drachms  and  one 
scruple,  of  gummy  extract ;  and,  by  di- 
gesting the  residuum  in  alcohol,  three 
drachms  and  one  scruple  of  resinous  ex- 
tract ;  the  indissoluble  part  amounting 
here  to  seven  drachms  and  a  scruple.  In 
distillation,  alcohol  brought  over  little  or 
nothing  ;  but  tiie  distilled  water  was  con- 
siderably impregnated  with  the  particular 
ill  smell  of  the  opium. 

The  subtile  soft  kind  of  resinous  matter 
dicovers  itself  in  great  measure,  in  the 
bare  watery  solution  of  opium,  generally 
rising  to  the  surface  in  form  of  a  fat,  unc- 
tuous, frothy  substance.  This  is  the 
strongest  and  most  active  part  of  the  opi- 
um ;  a  few  grains  are  sufficient  to  kill  a 
dog,  who  could  bear  a  whole  drachm  of 
crude  opium.  From  a  pound  of  opium, 
we  may  collect  two  or  three  drachms  of 
this  balsam-like  substance ;  but  we  are 
not  to  imagine,  that  this  is  the  whole  quan- 
tity, which  the  opium  contains  :  beside 
what  thus  spontaneously  separates,  a  part 
remains  combined  with  the  rest  of  the 
juice,  and  probably  is  the  principle,  or  the 
direct  seat  of  the  principle,  that  gives  ac- 
tivity to  the  whole 

As  opium  in  substance  is  frequently 
found  to  be  productive  of  unfavourable 
consequences,  different  methods  have 
been  contrived  for  correcting  or  render- 
ing it  more  universally  safe,  but  none  have 
produced  a  medicine  better,  than  the  pure 
opium  itself. 

Opium  has  been  made  from  poppies 
equal  to  that  imported  from  abroad  : 
and  Doctor  Coxe  of  Philadelphia,  as- 
serts, that  the  inspissated  milky  juice  of 
the  common  garden  lettuce,  is  precisely 
similar  in  its  effects,  to  the  opium  from 
Turkey.  The  reverend  Mr.  Cartwright 
too,  is  said  to  have  found  the  same  thing. 
Opium  has  been  made  in  the  United 
States. 

The  following  experiments,  on  the  cul- 
tivation of  the  poppy  plant,  and  the  me- 
thod of  procuring  opium,  &c.  by  Dr.  Shad- 
rach  Ricketson,  of  Dutchess  county,  New 
York  ;  taken  from  the  American  Maga- 
zine published  in  New  York,  may  be  use- 
ful in  addition. 

Opium  is  the  produce  of  the  papaver 
somniftntm  of  Linnaeus,  which,  as  a  genus 
comprehends  two  species,  viz.  1.  The 
double ;  2.  The  single ;  each  of  which  in- 
cludes several  varieties,  as  to  the  colour 
of  the  flowers,  some  being  white,  some 
ed,  others  purple  and  variegated. 

From  history  we  are  told,  that  in  the 


several  provinces  of  Asia,  it  is  the  large 
white  poppy  only,  that  is  cultivated  for 
the  purpose  of  collecting  opium  ;  but  from 
the  trials  I  have  made,  I  am  of  opinion  that 
it  is  a  matter  of  indifference,  which  species 
or  variety  of  the  plant  is  cultivated,  for  the 
purpose  of  collecting  opium ;  as  they  all 
afford,  when  tapped,  a  juice  that  is  simi- 
lar as  to  quantity,  colour,  and  every  other 
respect,  both  fresh,  and  when  dried ;  how- 
ever,! have  thought  that  the  large  double 
species,  produces  the  greatest  number  of 
heads,  and  consequently  the  greatest 
quantity  of  juice  from  one  seed  ;  but  of 
this,  I  have  not  yet  had  sufficient  trials  to 
be  certain. 

Among  the  poppies  cultivated,  with  a 
view  to  make  the  present  experiments,  I 
had  some  that  had  thirty  heads  apiece, 
all  of  which  sprung  from  one  seed,  and 
from  one  original  stock. 

The  poppy  seeds  in  this  country,  should 
be  sown  or  planted,  about  the  middle  of 
May,  in  rich,  moist  ground. 

The  ground  should  be  formed  into  areas 
of  about  four  feet  in  width.  The  seeds 
should  be  planted,  at  about  ten  or  twelve 
inches  distance,  in  transverse  rows,  which 
should  always  be  about  the  same  distance 
from  each  other. 

Shallow  holes,  of  an  inch  depth,  should 
be  made  in  the  rows,  at  the  distance  men- 
tioned :  the  seeds  put  in,  and  covered  over 
even  with  the  ground ;  after  which  they 
are  suffered  to  remain,  till  the  plants  are 
grown  about  four  inches  high,  when,  es- 
pecially if  the  land  is  dry  and  not  fertile, 
they  may  be  frequently  watered  and  ma- 
nured, the  best  kind  for  which  last  pur- 
pose, is  said  to  be  a  compost  of  ashes, 
dung,  and  a  nitrous  earth. 

They  are  said,  in  the  East-Indies,  to 
water  them  again  profusely,  just  before 
the  flowers  appear ;  but  as  I  have  had 
them  grow  very  luxuriant  and  succulent, 
in  good  ground,  without  either  manuring 
or  watering,  I  am  disposed  to  think,  that 
the  advantages  arising  from  this  last  par- 
ticular, are  not  equal  to  the  trouble  of 
doing  it. 

It  is  scarcely  necessary  to  remark,  that 
the  plants,  at  their  first  coming  up,  should 
be  kept  clean  from  weeds,  and  the  like, 
which  may  be  done  with  very  little  trou- 
ble, with  a  small  hoe,  especially  if  the 
seeds  are  planted  after  the  manner  I  di- 
rected, that  is,  in  rows. 

Having  said  all  that  is  necessary,  on  the 
cultivation  of  the  plant,  I  shall  now  pro- 
ceed to  describe  the  method  of  obtaining 
its  juice,  which,  when  inspissated  to  api- 
lular  consistence  is  called  opium. 

The  states  of  the  plants,  wherein  I  have 


ORA 


ORE 


found  them  to  yield  more  juice,  are  just 
before,  in  the  time  of,  und  immediately 
after  flowering,  the  plants  being  arrived 
to  one  or  the  other  of  the  states  above 
mentioned. 

We  then  proceed  to  that  part  of  the 
process,  called  tapping,  which  we  are  told 
is  done  in  Asia,  by  making  two  or  three 
longitudinal  incisions,  in  the  half  grown 
capsules,  without  penetrating  their  cavi- 
ties at  sunset,  and  the  plants  suffered  to 
remain  till  morning,  when  the  juice  is  to 
be  scraped  off,  and  worked  in  a  proper 
vessel,  in  a  moderate  heat,  till  it  becomes 
of  a  pilular  consistence ;  which  method, 
with  several  others,  I  have  tried,  but  none 
have  succeeded  so  well  with  me  as,  in  a 
sun-shining  day,  to  cut  off  the  stocks  at 
about  an  inch  distance  from  their  flowers 
or  capsules,  and  as  soon  as  the  juice  ap- 
pears, which  it  does  at  first  equally  well 
on  the  part  of  the  stalk  cut  off  with  the 
capsule  or  flower  as  on  the  standing  part, 
to  collect  it  with  a  small  scoop  or  pen- 
knife, the  last  of  which  I  have  found  to 
answer  the  purpose  very  well.  After  the 
juice  ceases  to  appear  on  the  top  of  the 
standing  stalk,  it  should  be  cut  off  about 
an  inch  lower,  when  it  will  be  found  to 
yield  almost  as  freely  as  before,  and  re- 
peated as  long  as  the  juice  appears. 

The  juice,  when  collected,  should  be 
put  into  an  evaporating  pan,  placed  in  the 
sun's  heat,  and  frequently  stirred  till  it 
becomes  of  a  consistence  to  form  into 
pills,  or  made  into  roils,  for  keeping  or 
transportation. 

The  quantity  of  opium  that  may  be 
procured,  depends  very  much  on  the 
largeness  of  our  plants,  and  the  care  used 
in  collecting  it. 

ORANGE.— The  flowers  of  orange 
trees  afford,  by  distillation,  a  very  fra- 
grant essential  oil.  From  the  rind  of  the 
fruit  an  essential  oil  may  be  obtained  by 
expression.  The  juice  of  the  fruit  con- 
tains an  essential  acid  salt,  mixed  with 
much  mucilage.  This  salt  may  be  ob- 
tained in  crystals,  by  diluting  the  juice, 
clarifying  it  with  whites  of  eggs,  and  eva- 
poration. The  oil  may  be  obtained  by  ex- 
pression. 

The  Orange-tree  is  divided  into  several 
varieties,  of  which  the  most  esteemed  are 
those  of  China  and  Seville :  it  is  seldom 
raised,  excepting  in  the  hot-houses  of  the 
curious;  and,  its  culture  being  the  same 
as  that  of  Citron,  v\e  refer  the  reader 
to  that  article. 

The  flowers  of  the  orange-tree  are 
highly  esteemed,  on  account  of  their  odo- 
riferous perfume  :  they  are  of  a  slightly 
pungent,  bitter  taste,  and  communicate 


their  flavour,  by  infusion,  to  rectified  spi- 
rit ;  and  also,  by  distillation,  both  to  spi- 
rit and  water.  Formerly  they  were  in 
great  repute,  on  account  of  their  suppos- 
ed efficacy  in  convulsive  and  epileptic 
cases,  though  later  experience  has  not 
confirmed  these  advantages — similar  vir- 
tues have  been  attributed  to  the  leaves, 
which  have  likewise  been  found  ineffec- 
tual in  those  complaints. 

The  juice  of  oranges  is  a  pleasant  sub- 
acid liquor,  which  has  often  proved  of 
service  in  inflammatory  or  febrile  disor- 
ders by  diminishing  heat,  allaying  thirst, 
and  promoting  the  salutary  discharges. 
It  is  likewise  eminently  useful  in  the  scur- 
vy, and  has,  therefore,  been  introduced 
into  the  navy,  as  part  of  the  stores  of 
ships  destined  for  long  voyages. 

Nor  is  the  outer  rind  less  valuable,  as 
it  forms  the  basis  of  an  excellent  con- 
serve ;  and,  when  preserved  with  sugar, 
is  deservedly  esteemed  in  desserts,  being 
a  grateful  aromatic  bitter,  and  one  of  the 
best  stomachics. — There  is  also  an  oil  ex- 
pressed from  the  orange-peel,  which  is 
sold  under  the  name  of  Bergamot. 

From  the  flowers  of  this  tree,  an  essen- 
tial oil  is  prepared  in  Portugal  and  Italy, 
termed  Essentia  JVeroli  :  this  perfume  is 
sa-id  to  possess  a  more  delicate  and  agree- 
able fragrance  than  even  the  Ittur  of 
Itcses  ;  but  it  is  with  difficulty  procured. 

Lastly,  the  Seville,  or  Bitter  Orange,  is 
seldom  employed  in  medicine  at  present ; 
the  China  orange  being  generally  substi- 
tuted. 

ORANGE  WINE. — Mr.  Johnson  has 
given  the  following  recipe  for  this  li- 
quor. 

Take  the  expressed  juice  of  eight  Se- 
ville (sour)  oranges,  and  having  one  gal- 
lon of  water  wherein  3  lbs.  of  sugar  have 
been  dissolved,  boil  the  water  and  sugar 
for  20  minutes ;  skim  constantly,  and 
when  cooled  to  a  proper  heat  for  fermen- 
tation, add  the  juice  and  the  outer  rind 
of  the  orange  thinly  shaved  off,  and  put- 
ting all  into  a  barrel,  let  it  be  frequently 
stirred  for  two  or  three  days,  and  then 
close  bunged  for  six  months  or  longer  be 
fore  bottling. 

ORCHAL,  or  Cudeear,  of  some,  is  the  i 
Lichen  Roccella  of  Linnxus,  used  in  dye 
ing.    See  Dyeing. 

ORE. — In  presenting  our  readers  with 
the  following  observations,  we  intend- 
ed to  have  embraced  a  catalogue  of 
sundry  American  ores  ;  but,  owing  to  our 
information  being  confined,  from  the  little 
which  is  known  on  the  subject,  we  have 
to  remark,  in  a  general  way,  that  the  ores 


ORE 


ORE 


of  metals  are  found,  almost  all,  within,  or 
in  the  neighbourhood  of,  the  United 
States  :  as  to  stating- their  locality,  it  would 
be  impossible  to  do  so,  in  order  to  render 
the  information  connected.  A  work  of  this 
kind  has  already  been  attempted  (and  is 
now  progressing)  by  Dr.  Bruce,  professor 
of  mineralogy,  New- York;  at  the  conclu- 
sion of  which,  a  valuable  fund  of  infor- 
mation will  be  presented  to  the  American 
public.  Whatever  has  appeared  hereto- 
fore is  imperfect,  and  by  no  means  con- 
clusive. 

In  noticing  the  ores  of  metals,  the  sub- 
ject of  reduction,  &c.  has  been  consider- 
ed as  a  proper  place  in  which  every  in- 
formation, although  probably  given  be- 
fore, may  be  considered.  The  length  of 
the  article,  for  which  we  are  principally 
indebted  to  Nicholson,  is  therefore  ob- 
vious 

Ores  are  native  substances,  containing 
the  metals  in  an  altered  state,  in  all  cases, 
either  combined  with  some  foreign  sub- 
stance, which  deprives  them  of  mallea- 
bility and  metallic  brilliancy,  or  else  so  in- 
timately mixed,  that  the  particles  of  me- 
tal cannot  be  discerned.  In  all  cases 
wherein  the  metallic  substance  is  clearly 
distinguishable,  it  is  not  called  an  ore,  but 
a  native  metal. 

The  metal  in  most  ores  is  in  the  state 
of  an  oxide.  When  ores  contain  nothing 
but  the  oxide  of  the  metal  with  the  addi- 
tion of  more  or  less  carbonic  acid,  they 
were  formerly  said  to  be  calciform ;  but 
when  they  are  combined  with  other  sub- 
stances, they  were  said  to  be  mineralized. 
The  mineralizers  are  either  arsenic  or 
sulphur.  Beside  the  mineralizers,  there 
are  various  stony  matters,  which  accom- 
pany ores  in  a  certain  peculiar  way,  with 
regard  to  crystallization  and  appearance ; 
which  has  occasioned  miners  to  consider 
them  as  possessing  an  affinity  to  the  ore. 
This  stony  accompaniment,  of  which  a 
better  notion  may  be  formed  by  inspec- 
tion of  ores  than  from  any  general  de- 
scription, is  called  the  matrix  of  the  ore. 
The  rocks  that  lie  over  the  veins  are  call- 
ed the  roof ;  those  that  lie  under  them, 
the  floor,  and  by  some  the  hading.  The 
matrix  is  almost  always  a  finer  species  of 
stone  than  the  surrounding  rocks,  though 
of  the  same  genus.  Even  the  rocks  them- 
selves are  of  a  finer  grain  as  they  ap- 
proach the  vein.  There  is  no  matrix  pe- 
culiarly appropriated  to  any  metal :  it  has 
Only  been  remarked,  that  tin  is  generally 
found  among  stones  of  the  siliceous  ge- 
nus, and  lead  very  frequently  among 
those  of  the  calcareous.  See  Metal- 
lurgy, and  the  several  metals. 


Ores  therefore  consist,  1.  of  metallic 
substances  in  the  state  of  oxide?  or,  2. 
of  these  substances  combined  with  other 
matters,  with  which  they  are  said  to  be 
mineralized. 

Mineralized  ores  are — 1.  Simple,  con- 
taining only  one  metallic  substance  ;  or, 
2.  Compound,  containing  two  or  more  me- 
tallic substances. 

Of  the  simple,  and  also  of  the  com- 
pound ores,  four  kinds  may  be  distin 
guished : 

1.  Ores  consisting  of  metallic  sub- 
stances mineralized  by  sulphur,  or  sul- 
phurets.  Such  is  the  lead  ore,  called  ga- 
lena, composed  of  lead  and  sulphur. 

2.  Ores  consisting  of  metallic  sub- 
stances mineralized  by  arsenic  Such  is 
the  white  pyrites,  containing  iron  and 
arsenic. 

3.  Ores  consisting  of  metallic  sub- 
stances mineralized  by  sulphur  and  by 
arsenic.  Such  is  the  ruby  silver  ore,  con- 
taining silver,  arsenic,  and  sulphur. 

4.  Ores  consisting  of  metallic  substances 
mineralized  by  saline  matters.  Such  is 
the  native  sulphats.  Such  also  is  the  cor- 
neous silver  ore,  which  is  silver  combined 
with  muriatic  acid.  To  this  class  also 
may  be  referred  the  silver  mineralized  by 
an  alkaline  substance,  which  Mr.  Von 
Justi  says  he  has  discovered. 

Henckel,  and  after  him  Cramer  and 
Macquer,  affirm,  that  in  mineralized  ores, 
beside  the  above-mentioned  metallic  and 
mineralizing  substances,  are  also  contain- 
ed a  metallic  and  an  unmetallic  earth. 
But  Wallerius  affirms,  that  the  existence 
of  such  earths  cannot  be  shown,  and  that 
sulphur  is  incapable  of  dissolving  unme- 
tallic earths,  and  even  the  oxides  of  all 
metallic  substances,  excepting  those  of 
lead,  bismuth,  and  nickel. 

Metals  and  metalliferous  ores  are  found 
in  various  places. 

I.  They  are  found  under  water,  in  beds 
of  rivers,  lakes,  and  seas,  and  chiefly  at 
the  flexures  of  these :  such  are  the  auri- 
ferous and  ferruginous  sands,  grains  of 
native  gold,  ochres,  and  fragments  of 
ores  washed  from  mines. 

II.  They  are  found  dissolved  in  water  : 
such  are  the  mineral  waters  containing 
sulphats  of  iron,  copper,  or  zinc 

III.  They  are  found  upon  the  surface  of 
the  earth.  Such  are  many  ochres  ;  me- 
talliferous stones,  sands,  and  clays  ;  and 
lumps  of  ore.  Mr.  Gmelin  says,  that  in 
the  northern  parts  of  Asia  ores  are  almost 
always  found  upon  or  near  the  surface  of 
the  ground. 

IV.  They  are  found  under  the  surface 
of  the  earth.    When  the  quantity  of  these 


OttE 


ORE 


collected  in  one  place  is  considerable,  it 
*s  called  a  mine. 

Subterranean  metals  and  ores  are  dif- 
ferently disposed  in  different  places. 

1.  Some  are  infixed  in  stones  and 
earths,  forming-  nodules  or  spots  diverse- 
ly coloured. 

2.  Some  are  equally  and  uniformly  dif- 
fused through  the  substance  of  earths  and 
stones,  to  which  they  give  colour,  density, 
and  other  properties.  Such  are  the  great- 
est part  of  those  earths,  stones,  sands, 
clays,  crystals,  flints,  gems,  and  spars, 
which  arc  coloured. 

3.  Some  form  strata  in  mountains. 
Such  are  the  slates  containing  pyrites, 
copper  ore,  lead  ore,  silver  ore,  or  blend. 
These  lie  in  the  same  direction  as  the  stra- 
ta of  stones,  betwixt  which  they  are 
placed  ;  but  ihey  differ  from  the  ordinary 
strata  in  this  circumstance,  that  the  thick- 
ness of  different  parts  of  the  same  metal- 
liferous stratum  is  often  very  various ; 
whereas  the  thickness  of  the  stony  strata 
is  known  to  be  generally  very  uniform. 

4.  Fragments  of  ores  are  frequently 
found  accumulated  in  certain  subterra- 
nean cavities,  in  fissures  of  mountains,' or 
interposed  betwixt  the  strata  of  the  earth. 
These  are  loose,  unconnected,  frequently 
involved  in  clay,  and  not  adherent  to  the 
contiguous  rocks  or  strata  immediately,  or 
by  intervention  of  spar  or  of  quartz,  as 
the  ores  found  in  veins  are.  Tin  and  iron 
mines  are  frequently  of  the  kind  here  de- 
scribed. 

5.  Large  entire  masses  of  ores  are 
sometimes  found  in  the  stony  strata  of 
mountains.  These  are  improperly  called 
cumulated  veins,  because  their  length  re- 
latively to  their  breadth  and  depth  is  not 
considerable. 

6.  Some  instances  are  mentioned  of  en- 
tire mountains  consisting  of  ore.  Such 
is  the  mountain  Taberg,  in  Smoland  ;  and 
such  are  the  mountains  of  Kerunavara 
and  Luosavara,  in  Lapland,  the  former  of 
which  is  1400  perches  long,  and  100 
perches  broad.  These  mountains  consist 
of  iron  ore. 

7-  Lastly,  and  chiefly,  metals  and  ores 
are  found  in  oblong  tracts,  forming  masses 
palled  veins,  which  lie  in  the  stony  strata 
composing  mountains. 

The  direction  of  veins  greatly  varies, 
some  being  straight  and  others  curved. 
Their  position  also  respecting  the  horizon 
is  very  various  ;  some  being1  perpendicu- 
lar, some  horizontal,  and  the  rest  being 
of  the  intermediate  degrees  of  declivity. 

The  dimensions,  the  quality,  and  the 
quantity  of  contents,  and  many  other  cir- 
cumstances of  veins,  are  also  very  var 
rious.  Miners  distinguish  the  several 
VOL.  II. 


kinds  of  veins  by  names  expressive  cjf 
their  differences.  Thus  veins  are  said  to 
be  deep ;  perpendicular ;  horizontal,  or 
hanging-,  or  dilated  ;  rich  ;  poor  ;  morn- 
ing, noon,  evening,  and  night  veins,  by 
which  their  direction  toward  that  point  of 
the  compass  where  the  sun  is  at  any  of 
these  divisions  of  the  natural  day,  is  sig- 
nified. 

Some  parts  of  veins  are  considerably 
thicker  than  others.  Small  veins  fre- 
quently branch  out  from  large  veins,  and 
sometimes  these  branches  return  into  the 
trunk  from  which  they  issued.  These 
veins,  from  which  many  smaller  veins  de- 
part, have  been  observed  to  be  generally 
rich. 

Veins  are  variously  terminated :  1.  by 
a  gradual  diminution,  as  if  they  had  been 
compressed,  while  yet  soft,  by  superin- 
cumbent weight,  or  by  splitting  and  di- 
viding into  several  smaller  veins :  or,  2. 
they  are  terminated  abruptly,  together 
with  their  proper  strata  in  which  they  lie. 

This  abrupt  termination  of  veins  and 
strata  is  occasioned  by  their  being  cross- 
ed  by  new  strata  running  transversely  to 
the  direction  of  the  former ;  or  by  perpen- 
dicular fissures  through  the  strata ;  v\  Inch 
fissures  are  frequently  filled  with  alluvial 
matters,  or  with  water,  or  are  empty. 
These  perpendicular  fissures  seem  to 
have  been  occasioned  by  some  rupture  or 
derangement  of  the  stratum  through 
which  the  vein  passes,  by  which  one  part 
of  it  has  been  raised  or  depressed,  or  re- 
moved aside  by  the  other,  probably  by 
earthquakes.  Where  the  vein  is  termi- 
nated abruptly,  it  does  not  cease,  and  is 
only  broken  and  disjoined ;  and  is  often 
recovered  by  searching  in  the  anulagous 
parts  of  the  opposite  side  of  the  deranged 
stratum.  A  principal  part  of  the  art  of 
miners  consists  in  discovering  the  modes 
of  their  derangements  from  external 
marks,  that  they  may  know  where  to 
search  for  the  disjoined  vein. 

The  contents  of  veins  are  metals  and 
metalliferous  minerals,  as  the  several 
kinds  of  ores,  pyrites,  blends,  guhrs ;  the 
several  kinds  of  spars,  quartz,  horn-blend, 
in  which  the  ores  are  generally  imbedded, 
or  enveloped,  and  which  compose  the  ma- 
trix of  the  ore ;  stalactites ;  crystalliza- 
tions of  these  metalliferous  and  stony  sub- 
stances, encrusting  the  small  cavities  of 
the  circumjacent  rock ;  and  lastly,  Water, 
which  flows  or  drops  through  crevices  in 
that  rock. 

In  a  vein,  ores  are  found  sometimes  at- 
tached to  the  rock  or  stratum  through 
which  he  vein  runs,  but  more  frequently 
to  a  matrix  which  adheres  to  the  rock ; 
and  sometimes  both  these  kinds  of  adbe* 
z 


ORE 


ORE 


sipn  occur  in  the  same  vein  at  different 
places.  Frequently  between  the  matrix 
and  the  rock  a  thin  crust  of  stone*  or  of 
earth,  is  interposed,  called  by  authors  the 
fimbria  of  the  ore. 

The  matrix,  or  the  stone  in  which  the 
ore  lies  enveloped,  is  of  various  kinds  in 
different  veins.  And  some  kinds  of  stone 
seem  better  adapted  than  others  to  give 
reception  to  any  ore,  or  to  the  ores  of  par- 
ticular metals  'Thus  quartz,  spar,  rluats, 
and  horn-blend,  give  reception  to  all  ores 
and  metals,  but  slates  chiefly  to  copper 
and  silver,  and  never  to  tin;  calcareous 
and  sparry  matrices,  to  lead,  silver,  and 
tin  ;  and  mica  to  iron. 

Veins  lie  in  strata  of  different  kinds  of 
stone ;  but  more  frequently  in  some  kinds 
of  stone  than  in  others.  Thus,  of  the  sim- 
ple or  uncompounded  stones  which  com- 
pose strata,  the  following  are  metallifer- 
ous :  calcareous  stones  ;  slaty  sand  stone ; 
feltspar;  quartz,  sometimes  jasper,  fre- 
quently slates,  and  chiefly  micaceous  or 
talky  stones,  and  horn-blend.  No  veins 
have  been  found  in  gypseous  or  siliceous 
strata,  though  cherts  and  flints  frequently 
contain  metallic  particles,  and  some  in- 
stances have  been  observed  of  ores  of  sil- 
ver and  tin  in  alabaster.  Of  compound 
stones,  those  are  said  to  be  chiefly  metal- 
liferous, which  consist  of  particles  of 
horn-blend.  Veins  have  also  been  found 
in  the  red  granite ;  but  seldom,  if  ever, 
in  any  other  granite,  or  in  porphyry.  In 
general,  veins  are  more  frequently  found 
in  soft  fissile,  and  friable  strata,  than  in 
those  which  are  compact  and  hard. 

A  vein  sometimes  passes  from  one  stra- 
tum into  the  inferior  contiguous  stratum 
Sometimes  even  the  veins  of  one  stratum 
do  so  correspond  with  those  of  an  inferior 
Stratum,  the  contiguity  of  which  with  the 
former  is  interrupted  by  a  mass  of  differ- 
ent matter,  through  which  the  veins  do 
not  pass,  that  they  seem  originally  to  have 
been  continued  flom  one  stratum  to  the 
other. 

Thus,  in  the  mines  of  Derbyshire,  where 
the  veins  lie  in  strata  of  lime-stone,  the 
contiguity  of  which  strata  with  each  other 
is  interrupted  in  some  places  by  a  blue 
marl  or  clay,  and  in  other  places  by  a 
compound  stone  called  toadstone,  the 
veins  of  one  stratum  frequently  corres- 
pond with  the  veins  of  the  inferior  stra- 
tum of  lime-stone ;  but  are  never  conti- 
nued through  the  interposed  clay  or  toad- 
stone.  But  we  must  observe,  that  these 
interposed  masses,  the  blue  marl,  clay, 
and  toadstone,  have  not  the  uniform  thick- 
ness, observable  in  regular  strata,  but  are 
especially  the  toadstone)  in  some  places 


a  few  feet  in  depth,  and  in  others  some 

hundreds  of  yards. 

The  above  disposition  seems  to  indi- 
cate, that  these  several  strata  of  limestone 
have  been  originally  contiguous ;  that  the 
veins  now  disjoined  have  been  once  con- 
tinued ;  that  these  strata  of  limestone  have 
been  afterward  separated  by  some  violent 
cause,  probably  by  the  same  earthquakes 
which  have  in  a  singular  manner  shatter- 
ed the  strata  of  this  mountainous  country; 
that  the  interstices  thus  formed  between 
the  separated  strata  have  been  filled  with 
such  matters  as  the  waters  could  insinu- 
ate, probably  with  the  mixed  comminuted 
ruins  of  shattered  strata ;  or  with  the  lava 
of  neighbouring  volcanoes,  of  which  many 
vestiges  remain. 

To  the  above  historical  sketch  of  mines 
it  may  not  be  improper  to  add  some  con- 
jectural remarks  concerning  their  forma- 
tion. 

Those  ores  which  are  found  under  wa- 
ter (I) ;  upon  the  surface  of  the  earth 
(III) ;  in  fissures  of  mouutains  and  sub- 
terranean cavities,  accumulated,  but  not 
adherent  to  the  contiguous  rocks  (IV) ; 
seem  from  their  loose,  unconnected,  bro- 
ken appearances  to  have  been  conveyed 
by  alluvion. 

All  martial  ochres  have  probably  been 
separated  from  ferruginous  waters  (II), 
either  spontaneously,  or  by  calcareous 
earth  ;  and  these  waters  seem  to  have  ac- 
quired their  metallic  contents  by  dissolv- 
ing the  sulphat  which  is  produced  by  the 
spontaneous  decomposition  of  martial  py- 
rites. The  ochres  of  copper,  zinc,  and, 
perhaps,  of  several  other  metals,  have  pro- 
bably been  precipitated  from  waters  con- 
taining their  sulphats  by  some  substance, 
as  calcareous  earth,  more  disposed  to 
combine  with  acids ;  and  these  waters 
have  probably  been  rendered  metallife- 
rous, by  dissolving  the  sulphats  produced 
by  a  combustion  of  cupreous  pyrites,  and 
of  the  ore  of  zinc  called  blend ;  for  these 
minerals  are  not,  as  martial  pyrites  is,  sus- 
ceptible of  decomposition  spontaneously, 
that  is,  by  air  and  moisture. 

The  metalliferous  nodules  and  spots 
(IV,  1,)  seem  to  have  been  infixed  in 
stones  while  these  were  yet  soft  Perhaps 
the  metalliferous  and  lapideous  particles 
were  at  once  dissohed  and  suspended  in 
the  same  aqueous  menstruum,  and  during 
their  concretion  crystallized  distinctly,  as 
different  salts  do  when  dissolved  in  the 
same  fluid. 

The  earths  and  stones  uniformly  co- 
loured by  metals  (IV,  2,)  were  also  pro- 
bably in  a  soft  state  whiie  they  received 
those  tinges.   The  opake  coloured  stones 


ORE 


sfecm  to  have  received  their  colour  from 
metallic  oxides  mixed  and  diff  used  through 
the  soft  lapideous  substance;  and  the 
transparent  coloured  stones  have  probably 
received  their  colours  from  salts,  or  from 
metallic  particles  dissolved  in  the  same 
water,  which  softened  or  liquefied  the 
stony  substance ;  which  metallic  salts  and 
particles  were  so  much  diffused,  that  they 
could  not  be  distinctly  crystallized  That 
all  stones  have  been  once  liquid  and  dis- 
solved in  water  appears  probable,  not  only 
from  their  regular  crystallized  forms,  but 
also  from  the  solubility  of  some  stones,  as 
of  gypseous  and  calcareous  earths,  in  wa- 
ter ;  and  from  the  water  which  we  know 
is  contained  in  the  hardest  marbles,  as 
well  as  in  alabasters ;  to  which  water 
these  stones  owe  the  crystallization  of 
their  particles. 

The  veins  called  cumulated  (IV,  5,)  and 
the  entire  metalliferous  mountains  (IV, 
6,)  are  believed  by  Wallerius  to  be  analo- 
gous to  the  nodules  (IV,  1,).  These  me- 
talliferous substances  seem  to  have  been 
originally  formed  or  concreted  in  the 
places  where  they  are  found. 

The  metalliferous  strata  (IV,  3,)  have 
probably  been  insinuated  between  the  la- 
pideous strata,  after  the  separation  of 
these  from  each  other  by  some  violent 
cause ;  in  the  same  manner  in  which  it 
was  supposed,  that  the  clay  and  toadstone 
have  been  insinuated  betwixt  the  several 
strata  of  limestone  in  Derbyshire.  The 
matters  thus  insinuated  may  have  been 
either  fluid,  which  would  afterward  crys- 
tallize, and  form  entire  regular  masses  ; 
or  they  may  have  been  the  ruins  of  shat- 
tered strata,  and  veins  brought  by  waters, 
and  there  deposited :  in  which  case  they 
will  appear  broken  and  irregular.  The 
metalliferous  strata,  though  frequently 
confounded  with  the  horizontal  or  dilated 
veins,  may  be  distinguished,  according  to 
Wallerius,  from  these,  by  the  following- 
properties  : — 

1.  They  are  generally  thinner  and  much 
broader  than  the  veins  called  dilated. 

2.  They  are  seldom  found  at  a  greater 
depth  than  100  perches,  and  generally  in 
the  neighbourhood  of  veins,  from  which 
they  probably  have  received  their  con- 
tents. 

3-  From  their  want  of  the  thin  incrus- 
tations called  fimbria:,  which,  as  has  been 
observed,  are  frequently  interposed  be- 
twixt the  rock  and  the  ore,  or  its  matrix ; 
and  from  their  want  of  the  other  proper- 
ties of  veins. 

But  in  veins,  properly  so  called,  the 
strongest  marks  exist  of  ores  having  been 
there  concreted,  and  not  carried  thither 
and  deposited  in  their  present  state.  Their 


regular,  unbroken  appearance,  their  adlle> 

sion  to  the  contiguous  rock,  either  imme- 
diately or  by  intervention  of  a  matrix,  the 
regular  appearance  of  this  matrix  enve- 
loping the  ore,  the  frequent  crystalliza- 
tion of  the  ore,  and  of  the  other  contents 
of  the  vein,  indicate  that  ores,  as  well  as 
the  other  solid  contents,  have  been  there 
concreted  from  a  fluid  to  a  solid  state. 

Most  authors  believe,  that  veins,  and 
the  perpendicular  clefts  in  the  stony  strata' 
of  mountains,  called  fissures,  have  been 
produced  by  the  same  cause ;  or,  rather, 
they  consider  veins  only  as  fissures  filled 
with  metalliferous  matters.  They  farther 
believe,  that  fissures  have  been  occasion- 
ed by  the  exsiccation  of  strata,  while 
these  were  passing  from  a  fluid  to  a  solid 
state.  Wallerius  imagines,  that  fissures 
have  been  formed  from  exsiccation ;  but 
that  veins  were  channels  made  through 
the  strata,  while  yet  soft  and  fluid,  by  wa- 
ter, or  by  the  more  fluid  parts  of  the  stra- 
ta, penetrating  and  forcing  a  passage 
through  the  more  solid  parts.  He  con- 
ceives, that  these  fluid  parts  conveyed 
thither  their  metalliferous  and  stony  con- 
tents, which  were  then  coagulated  or  con- 
creted He  supports  his  opinion  by  ob- 
serving, that  all  the  veins  of  the  same  stra- 
tum generally  run  parallel  to  each  other  ; 
that  they  frequently  bend  in  their  course  ; 
that  the  same  vein  is  sometimes  contract- 
ed and  sometimes  dilated;  that  veins  are 
frequently  terminated  by  being  split  or 
divided  into  inferior  veins  ;  that  veins  are 
frequently  wider  at  bottom  than  at  top, 
whereas  fissures  are  always  widest  at  top, 
and  are  very  narrow  below  ;  all  which  ap- 
pearances, he  thinks,  could  not  have  been 
produced  by  exsiccation 

From  these  reasons,  fissures  appear  to 
have  had  a  different,  and  from  the  dis- 
junction and  rupture  of  veins  crossed  by 
fissures,  they  seem  to  have  had  a  later 
origin  than  veins.  Whether  fissures  could 
have  been  produced  by  the  very  gradual 
exsiccation  of  these  large  masses,  or 
strongly  coherent  matter ;  or  whether 
they  have  been  produced  by  the  same 
violent  causes,  namely,  earthquakes  ;  by 
which  the  strata  in  which  fissures  are  ge- 
nerally found,  have  been  broken  and  de- 
ranged, and  by  which  metalliferous  moun- 
tains themselves  have  been  formed,  or 
their  strata  raised  above  their  original  le- 
vel, as  some  others  have  with  great  pro- 
bability conjectured,  cannot  with  certain- 
ty be  determined. 

Veins  are  seldom,  if  ever,  found  but  in 
mountains  :  the  reason  of  which  may  not 
improbably  be,  that  in  metalliferous  moun- 
tains we  have  access  to  the  more  ancient 
strata  of  the  earth,  which  in.  plains  jare 


ORE 


ORE 


Overcd  with  so  many  deposited,  alluvial, 
and  other  later  strata,  that  we  can  seldom 
if  evei  reach  the  former.  That  these 
mountains  consist  of  strata  which  have 
been  originally  lower  than  the  upper  stra- 
ta of  adjacent  plains,  appears  from  an  ob- 
servation which  has  been  made,  that  the 
strata  of  mountainous  countries  dip  with 
more  or  less  declivity  as  they  approach 
the  plains,  till  they  gradually  sink  under 
the  several  strata  of  those  plains,  and  are 
at  last  immersed  beyond  the  reach  of  mi- 
ners. This  leading  tact  in  the  natural  his- 
tory of  the  earth  has  been  observed  by  a 
sagacious  philosopher  Mr.  Mitchell,  in 
his  Conjectures  concerning  Earthquakes, 
&c.    Philos.  Trans.  1:60. 

That  the  inferior  strata  of  the  earth 
contain  large  quantities  of  pyritous,  sul- 
phurous, and  metalliferous  matters,  ap- 
pears, 

1.  From  the  subterranean  fires  in  those 
kife-ior  strata,  which  produce  volcanoes, 
and  probably  earthquakes  (as  Mr.  Mitch- 
ell ingeniously  conjectures). 

2.  From  the  observation,  that  all  kinds 
of  mountains  are  not  equally  metallife- 
rous ;  but  that  veins,  especially,  are  only 
found  in  those  mountains,  which,  being- 
composed  of  very  ancient  strata,  are  called 
primeval ;  which  form  the  chains  and  ex- 
tensive ridges  on  the  surface  of  the  earth, 
which  direct  the  course  of  the  waters,  and 
which  consist  of  certain  strata,  the  thick- 
ness of  each  of  which,  its  genuine  quali- 
ties, and  its  position  relatively  to  the  other 
strata,  are,  in  different  parts  of  the  chain 
of  mountains  where  that  stratum  is  found, 
nearly  uniform  and  alike,  notwithstanding 
that  the  numbers,  and  the  inclinations  of 
the  strata  composing  contiguous  moun- 
tains, or  even  different  parts  of  the  same 
mountain,  are  often  very  various ;  and, 
therefore,  that  veins  are  seldom,  if  ever, 
found  in  the  mountains  called  by  authors 
allm  lal  and  temporary,  which  are  single, 
or  detached,  which  consist  not  of  strata 
uniformly  disposed,  but  of  alluvial  masses 
in  which  fragments  of  ores  may  be  some- 
times, but  veins  never,  found.  Neverthe- 
less, single,  and  seemingly  detached, 
mountains  in  small  islands  have  some- 
times been  found  to  be  metalliferous.  But 
we  must  observe,  that  these  mountains 
consist  of  unite]  m  strata ;  that  islands 
themselves,  especially  small  i  . lands,  may 
be  considered  as  eminent  parts  of  subma- 
rine ranges  of  mountains  ;  and  that  the 
mountains  of  such  islands  may  be  consi- 
dered as  apices  or  tops  only  of  inferior 
mountains. 

Those  mountains  are  said  to  be  most 
metalliferous  which  have  a  gentle  ascent, 
-a  moderate  height,  and  a  broad  basis,  the 


strata  of  which  are  nearly  horizontal,  and 
not  much  broken  and  disjoined.  In  these 
mountains,  at  least,  the  veins  are  less  in- 
terrupted, more  extended,  and  conse- 
quently more  valuable  to  miners,  than  the 
veins  in  lofty,  scraggy,  irregular  and  shat- 
tered mountains. 

Authors  dispute  concerning  the  time  in 
which  ores  have  been  formed,  some  refer- 
ring it  to  the  creation  of  the  world,  or  to 
the  first  subsequent  ages  ;  and  others  be- 
lieving that  they  have  been  gradually  from 
all  limes,  and  are  now  daily  forming. 
From  the  accretion  of  ores  and  of  then- 
matrices  to  their  proper  rocks,  and  from 
the  insertion  of  metalliferous  nodules  and 
striae  in  the  hardest  stones,  it  seems  most 
probable,  that  the  matter  of  those  veins 
and  nodules  is  nearly  coeval  with  the 
rocks  and  stones  in  which  they  are  enve- 
loped. 

Nevertheless,  it  cannot  be  doubted  but 
that  small  quantities,  at  least,  of  ores,  are 
still  daily  formed  in  veins,  fissures,  and 
other  subterranean  cavities.  Several  well 
attested  instances  confirming  this  opinion 
are  adduced  by  authors  :  Cronstedt  men- 
tions  an  incrustation  of  silver  ore,  that 
was  found  adhering  to  a  thin  coat  of  lamp 
black,  or  of  soot,  with  which  the  smoke 
of  a  torch  had  soiled  a  rock  in  a  mine  at 
Koningsberg,  in  Norway ;  and  that  this- 
incrustation  of  silver  ore  has  been  form, 
ed  by  a  metalliferous  water  passing  over 
the  rock.  Lehman  affirms,  that  he  pos» 
sesses  some  silver  ore  attached  to  the 
step  of  a  ladder,  found  in  a  mine  in  the 
Hartz,  which  had  been  abandoned  two 
hundred  years  ago  ;  and  that  several 
steps  of  ladders  similarly  incrusted  had 
been  found.  Many  other  instances  are 
mentioned  by  authors,  of  galena,  pyrites, 
silver  ores,  and  other  metalliferous  sub- 
stances having  been  found  adhering  to- 
wood,  to  fossil-coal,  to  stalactitical  incrus 
tations,  to  oyster-shells,  and  other  recent 
substances. 

From  these,  ar.d  from  similar  instances, 
it  seems  probable,  that  not  only  ochres 
and  fragments  of  ores  may,  with  other  aL 
luvial  matters,  be  now  daily  deposited, 
but  also  that  small  quantities  of  minera- 
lized ores  are  recently  formed ;  although 
many  histories  mentioned  by  Becker,  Bar- 
ba,  llenckel,  and  other  authors,  of  the  ens- 
ure renovation  of  exhausted  veins,  and  es- 
pecially those  of  the  growth  and  vegeta- 
tion of  metals  and  of  ores,  appear  to  be  at 
least  doubtful. 

Various  opinions  have  been  published 
concerning  the  formation  of  mineralized 
ores.  According  to  some,  these  ores  were 
formed  by  congelation  of  the  fluid  masses 
found  in  "mines,  called  gurhs.    Other  au- 


ORE 


ORE 


thors  believe,  that  ores  have  been  formed  1 
by  the  condensation  of  certain  mineral,  1 
metallic,  sulphureous,  and  arsenical  va-  1 
pours,  with  which  they  suppose  that 
mines  abound.  Some  have  even  affirm-  i 
ed,  that  they  have  seen  this  vapour  con-  1 
dense,  and  become  in  a  few  days  changed  I 
into  gold,  silver,  andother  metallic  matters. 

It  has  been  above  observed,  that,  from 
several  appearances  which  occur  in  veins, 
there  is  great  reason  to  believe,  that  ores 
have  not  been  carried  thither  and  depo- 
sited in  their  present  state,  but  have  been 
there  concreted  and  crystallized  ;  that  is, 
changed  from  a  fluid  to  a  solid  state.  But 
the  fluidity  of  the  metalliferous  matters  at 
the  time  of  their  entrance  into  veins  may 
have  been  occasioned  either  by  their  hav- 
ing been  dissolved  in  water,  if  they  were 
capable  of  such  solution,  or  by  their  hav- 
ing been  raised  in  form  of  vapour  by  sub- 
terranean fires.  For  the  disposition  to 
crystallize  is  acquired  by  every  homoge- 
neous substance  that  is  fluid,  whether  it 
have  received  its  fluidity  by  being  melted 
by  fire,  or  by  being  dissolved  in  a  liquid 
menstruum,  or  by  being  reduced  to  the 
state  of  vapour.  Thus,  crystals  of  sul- 
phur have  been  observed  to  be  daily  form- 
ed by  the  sulphureous  vapours  which  ex- 
hale in  the  neighbourhood  of  volcanoes. 

The  volatility  of  the  two  mineralizing 
substances,  sulphur  and  arsenic,  and  the 
power  which  volatile  bodies  possess  of 
elevating  a  certain  portion  of  any  fixed 
matter  which  happens  to  be  united  with 
them,  render  it  probable,  that  the  great- 
est part  at  least  of  mineralized  ores  have 
been  formed  of  vapours  exhaled  from  sub- 
terranean fires  through  the  cracks  in  the 
intervening  strata,  occasioned  by  those 
earthquakes  which  have  in  a  singular 
manner  broken  and  deranged  the  strata 
of  metalliferous  countries,  and  which,  as 
has  been  above  remarked,  have  been  pro- 
bably occasioned  by,  at  least  have  certain- 
ly been  always  accompanied  with,  subter- 
raneous fire. 

Description  of  a  Machine  for  raising  Ore 
from  Mines   By  Mr.  T.  Arkwright, 

of  Kendal,  Westmoreland,  {England.) 

A,  Plate  XII.  fig.  5,  is  an  endless  chain 
formed  of  thin  plates  of  iron,  through  the 
ends  of  which  plates  iron  bolts  are  pass- 
ed, which  keep  the  sides  of  the  chain  at 
a  certain  distance  asunder,  and  on  which 
the  buckets  to  contain  the  ore  are  sus- 
pended, B  C  D  E,  the  buckets  suspended 
on  the  iron  bolts,  G  H  I,  three  cylinders, 
round  which  the  chain  and  buckets  re- 
volve. The  two  cylinders  G  H  are  plac- 
ed above  the  shaft ;  the  cylinder  I  within 


the  mine.  Their  rims  are  so  much  higher 
than  the  body  of  the  cylinders,  as  to  ad- 
mit the  buckets  to  lie  within  the  rims. 

As  the  endless  chain  and  buckets  are- 
moved  forwards  by  a  power  applied  to 
the  axis  of  the  cylinder  G,  the  bolts  of 
the  chain  fall  into  notches  made  at  regu- 
lar distances  in  the  rims  of  that  cylinder, 
which  preserve  the  chain  from  slipping. 

As  each  empty  bucket  passes  under  the 
axis  of  the  bottom  cylinder  I,  it  loads  it- 
self with  ore  instantaneously  from  a  box 
K,  constantly  filling  by  the  workmen  be- 
low, which  box  rests  on  two  moveable 
pins  L,  at  that  end  furthest  from  the 
wheel,  and  on  an  iron  ketch  M  at  the 
other.  The  bucket  thus  filled  ascends  to 
the  top  of  the  cylinder  G :  and,  in  its  pas- 
sage betwixt  the  cylinders  G  and  H,  dis- 
charges its  contents  into  a  channel  or  re- 
ceiver placed  betwixt  them,  from  whence 
they  slide  into  a  cart  or  receptacle  placed 
underneath  the  inclined  trough  N.  The 
empty  bucket  passes  over  the  cylinder  H, 
descends  on  the  opposite  side  under  the 
cylinder  I,  and  loads  itself  again  at  K,  as 
before  mentioned ;  the  buckets  regularly 
loading  and  discharging  themselves, 
whilst  the  cylinder  G  is  kept  in  motion. 

O  is  a  racket-wheel  on  the  cylinder,  to 
prevent  a  retrograde  motion  in  the  chain, 
Fig.  2,  shews,  upon  a  large  scale,  the 
manner  in  which  the  box  K  above  men- 
tioned loads  the  buckets.  P  is  an  iron 
tooth  projecting  from  the  endless  chain „ 
which,  pressing  upon  the  catch  R,  under* 
neath  the  box  K,  occasions  that  part  of 
the  box  Hext  the  chain  to  sink  down,  and 
discharge  into  the  bucket  beneath  it  & 
quantity  of  ore  sufficient  to  fill  it.  As  the 
loaded  bucket  rises,  it  lifts  the  box  K  to 
its  former  place,  till  the  operation  is  rc 
peated  by  the  next  tooth  upon  the  chain. 

Ores  of  Antimony. 
Dr.  Bruce  observes,  that  in  recently  ex- 
amining some  mineral  productions  from 
Louisiana,  he  was  much  gratified  in  ob» 
serving  several  very  rich  specimens  of  this 
highly  valuable  metal.  Antimony  is  at  pre- 
sent in  so  much  demand,  that  our  type 
founders,  in  consequence  of  the  difficulty' 
of  obtaining  it  from  Europe,  have  for  some 
i  time  past  been  nearly  at  a  stand.  From 

■  the  assurance  that  this  ore  occurs  in  very 
;  considerable  quantities,  we  are  in  hopes 
i  that  such  will  be  the  supply,  that  our 
•  types  ere  long,  will  be  manufactured  en- 
l  tirely  from  American  materials. 
,      Antimony  has  been  found  in  the  native 

■  state  of  a  silver  colour,  and  its  texture 

■  composed  of  moderately  large,  shining 
i  plates.  It  has  the  same  habitudes  in  acids„ 


ORE 


OliE 


as  the  metal  reduced  from  the  sulphuret, 
and  aqua  regia  more  particularly  dissolves 
it  very  well.  The  solution  does  not  lose 
its  transparency  in  the  cold.  Alkalis  throw 
down  a  white  precipitate.  The  prussiat 
of  potash  affords  a  green  precipitate  with 
small  blue  specks,  which  shows  the  pre- 
sence of  iron.  In  the  fire,  native  antimo- 
ny melts  and  is  volatilized  in  white  flow- 
ers ;  but  a  substance  of  a  fat  and  oily  ap- 
pearance is  formed  round  the  fused  metal 
in  much  greater  abundance  than  with  the 
pure  metal.  Mongez  asserts,  that  this  is 
the  oxide  converted  into  giass  of  antimo- 
r.v.  On  the  first  impression  of  the  heat, 
a  slight  smell  of  arsenic  is  emitted,  which 
quickly  disappears.  Air  Sage,  in  fact, 
found  sixteen  per  cent,  of  arsenic  in  the 
native  antimony  from  Chalances,  near  Al- 
ternant,- in  Dauphiny.  If  this  native  ore 
l>e  fused  in  a  crucible  without  any  re- 
ducing matter,  a  very  neat  button  is  ob- 
tained, suseeptible  of  crystallization,  more  ' 
brilliant  and  clear  in  its  fracture,  which 
exhibits  larger  plates  than  before. 

The  appearances  of  this  native  metal, 
before  the  blowpipe,  correspond  with  those 
observed  in  the  larger  process.  It  evapo- 
rates in  smoke  with  a  smell  of  garlic  ;  a 
white  powder  is  deposited  on  the  char- 
coal, of  which  the  arsenical  portion  be- 
comes bh;ck  and  fixed,  on  application  of 
the  interior  cone  of  the  flame.  The  fluxes 
acquire  a  faint  hyacinth  tinge. 

There  is  a  native  antimony  at  Andres- 
berg,  from  100  parts  of  which  Kiaproth 
obtained  98  antimony,  1  silver,  and  0.25 
iron.    Its  specific  gravity  was  6.72. 

Mongez  likewise  acquaints  us  with  a 
native  oxide  of  antimony,  observed  by  him, 
upon  a  piece  of  the  native  antimony  from 
Chalances.  It  is  usually  crystallized  in 
very  white,  slender  needles,  in  some  por- 
tions confused  with  the  plates  of  the  anti- 
mony, and  in  others,  radiated  from  a  cen- 
tre exactly  like  the  crystallized  zeolite. 
These  did  not  contain  arsenic.  The  white 
earthy  ore  of  Tornavara  in  Galiicia,  is  an 
oxide  apparently  produced  from  the  de- 
composition of  native  sulphuret. 

There  is  likewise  a  white  antimonial  ore, 
in  which  the  oxide  appears  to  be  com- 
bined with  muriatic  acid;  but  it  is  very 
rare. 

The  most  common  and  abundant  ore  of 
antimony  is  known  in  commerce  simply 
by  the  name  of  antimony,  and  consists  of 
the  ore  in  combination  with  sulphur.  It 
is  composed  of  filaments,  or  needles,  ad- 
herent to  each  other,  either  parallel,  or 
divergent  from  a  centre.  These  are  fria- 
ble, brilliant,  usually  of  a  shining  metallic 
blueish-grey  colour ;  sometimes  of  a  live- 
ly chatoyant  appearance,  according  to 


Mongez  ;  but  I  think  on  recollection,  not' 
having  a  specimen  of  the  sort  before  mes 
that  these  colours,  though  variegated,  do 
not  change  their  position  with  the  eye  of 
the  observer,  or  at  least  exhibit  none  of 
that  internal  appearance  denoted  by  the 
word  chatoyant.  They  should,  therefore, 
be  called  iridescent. 

When  this  ore  of  antimony  possesses  a 
less  determined  internal  siructure,  it  may 
be  mistaken  for  the  small  grained  lead 
ore,  or  white  silver  ore,  or  iron  glimmer; 
but  it  may  be  distinguished  by  the  smell 
of  sulphur  it  exhibits  when  broken  or  rub- 
bed, and  still  more  effectually  by  its  fusi- 
bility, which  is  such  that  it  runs  in  the 
flame  of  a  candle.  The  sulphur  may  be 
easily  separated,  and  its  quantity  ascer- 
cerfained  by  aqua  regia,  which  dissolves 
the  metal,  and  leaves  the  sulphur  floating 
at  the  surface.  The  aqua  regia,  accord- 
ing to  Kirwan,  ought  to  consist  of  one  part 
nitric  and  four  muriatic  acid. 

The  specific  gravity  of  this  ore  of  anti- 
mony is  for  the  mo=.t  part  from  from  4  to 
4.2,  and  after  fusion  from  4.7  to  5.  There 
are  several  varieties : 

1.  The  gray  striated  ore  of  antimony. 

2.  Plumous  ore  of  antimony.  This  has 
the  form  of  small,  silky,  gray,  or  blueish 
filaments,  almost  always  efflorescent. 
There  are  some  specimens  of  a  deep  red, 
and  of  a  pulverulent  reddish  colour,  in 
prisms  efrloiescent  upon  the  gray  ore. 
The  ore  from  Tuscany  is  of  this  kind. 
Mr.  Sage  considers  the  red  plumous  ore 
of  antimony  as  a  native  golden  sulphur, 
and  the  pulverulent  reddish  ore  as  a  na- 
tive kermes  mineral. 

3.  The  solid  gray  ore  of  antimony.  This 
is  an  uniform  mass,  of  the  colour  of  po- 
lished iron  or  lead,  very  brittle,  and  its 
fracture  exhibits  small  brilliant  facets,  and 
sometimes  filaments.  It  melts  and  is  vo- 
latilized by  the  flame  of  a  candle. 

The  sulphuret  of  antimony  urged  by 
the  flame  of  the  blowpipe  is  liquefied, 
flows  on  the  charcoal,  soaks  into  it,  and 
at  length  entirely  disappears,  except  a 
portion  of  flowers,  which  are  deposited 
circularly.  One  hundred  parts  of  the  ore 
contain  twenty-four  parts  of  antimony 
slightly  oxkled,  and  twenty-six  of  sul- 
phur. 

The  red  ore  of  antimony  has  the  same 
texture  with  the  common  sulphureous  ore, 
but  its  fibres  are  not  so  coarse.  Walle- 
rius  distinguishes  three  varieties  found  in 
Hungary  and  Saxony,  viz.  the  red,  the  vi- 
olet, and  the  pale  red. 

Ores  of  Arsenic. 
Arsenic  is  found  native  in  Saxony,  Bo- 
hemia, Hungary,  and  elsewhere,  but  par- 


ORE 


ORE 


ticularly  at  St.  Marie  aux  Mines  in  Alsa- 
tia  It  is  often  found  of  no  determinate  | 
figure, friable,  and  pulverulent ;  but  some- 
times compact,  divided  into  thick  convex 
plates,  with  a  needle-formed  or  micaceous 
surface.  It  is  of  a  lead  colour  when 
fresh  broken,  and  may  be  cut  with  a  knife, 
like  compact  black  lead,  but  soon  black- 
ens by  exposure  to  the  air.  In  hardness 
it  seems  to  exceed  copper,  but  is  brittle 
like  antimony.  It  burns  with  a  small  flame, 
and  goes  off  in  smoke.  Cronstedt  says 
nothing'  of  the  residue,  but  Bergman  re- 
marks, that  he  never  found  native  arsenic 
without  iron. 

Native  arsenic  before  the  blowpipe, 
takes  fire,  emits  a  white  smoke,  and  co- 
vet s  the  charcoal,  with  Howers  of  arsenic, 
which  quickly  become  black.  A  strong 
smell  of  garlic  is  emitted.  If  the  portion 
of  iron  it  contains,  be  considerable,  it  re- 
mains on  the  coal;  if  not.  it  disappears 
It  communicates  a  yellowish  colour  to  the 
flux,  which  disappears  in  proportion  as 
the  arsenic  is  volatilized. 

Native  oxide  of  arsenic,  is  in  general 
scarce.  It  is  either  in  a  loose  or  powdery 
form,  or  else  in  white  semitransparent 
crystals.  Like  the  artificial  oxide,  it  is 
volatilized  by  heat,  emitting  a  smell  of 
garlic,  and  possesses  the  same  solubility 
in  water-  See  Arsenic  It  does  not  de- 
tonate with  nitre,  though  an  effervescence 
arises.  It  is  scarcely  soluble  in  the  sul- 
phuric acid,  something  more  in  the  muri- 
atic, but  most  perfectly  in  the  diluted  ni- 
tric acid.  Before  the  blowpipe,  it  evapo- 
rates in  white  flowers,  which  cover  the 
charcoal.  The  peculiar  smell  of  garlic, 
appears  to  be  sufficiently  distinctive  of 
this  semimetal;  but  Mongez  observes,  as 
the  characteristic  marks  of  the  respective 
flowers  of  arsenic,  antimony,  and  zinc, 
that  the  first,  when  distributed  upon  the 
charcoai,  become  suddenly  black,  if  touch- 
ed with  the  interior  part  of  the  flame,  the 
Second  remain  white,  and  the  third  become 
yellow 

The  combinations  of  arsenic  with  sul- 
phur, are  either  orpiment  or  realgar.  These 
are  also  produced  by  art.  See  these  words. 
Native  orpiment  is  of  a  yellow  colour,  in- 
clining to  red  in  some,  specimens,  and 
green  in  others.  It  is  frequently  mixed 
with  yellow  mica  and  spar,  which  cause 
it  to  appear  as  if  compounded  of  facets,  of 
greater  or  less  magnitude.  In  the  fire  its 
colour  becomes  obscure,  a  white  blueish 
flame  appears,  with  a  considerable  mixed 
smell  of  garlic  and  sulphur.  By  an  open 
fire  it  is  almost  entirely  volatilized,  and 
leaves  only  a  greenish  earthy  residue  ;  but 
in  a  close  vessel  it  melts,  and  in  cooling, 
becomes  the  reddish  mass  called  realgar. 


It  is  easily  distinguished  from  artificial  or- 
pimenl,  because  its  figure  is  almost  al- 
ways that  of  small,  silky,  light  crystals, 
or  granulated. 

Native  realgar  has  a  more  lively  colour, 
and  possesses  every  degree  of  transpa- 
rency, from  that  of  the  clear  red  crystals-, 
called  the  ruby  of  arsenic,  which  is  com- 
pact and  hard,  to  that  of  perfect  opacity. 
Its  habitudes  before  the  blowpipe  are  the 
same  as  those  of  orpiment. 

Bergman's  method  of  analysing  these 
ores,  consists  in  digesting  them  in  muria- 
tic acid,  adding  the  nitric  by  degrees,  to 
help  the  solution.  The  sulphur  will  be 
found  on  the  filter,  and  the  arsenic  will 
remain  in  the  solution,  from  which  it  may 
be  precipitated  in  its  metallic  form,  by 
zinc,  adding  to  the  solution. 

Mr.  Chenevix  gives  the  following,  a* 
the  most  certain  mode  of  ascertaining  the 
quantity  of  arsenic.  Digest  the  ore,  finely 
powdered,  in  nitric  acid  enough  to  acidify 
and  take  up  all  the  arsenic.  Pour  off  the 
liquor  ;  boil  the  residuum  in  a  little  water, 
filter,  and  mix  the  two  solutions.  Neutra- 
lize the  excess  of  acid  by  potash,  taking 
care  not  to  use  it  in  excess,  and  nit  rat  of 
lead,  as  long  as  any  precipitate  takes  place. 
Wash  the  precipitate  in  cold  water,  dry, 
and  weigh  it.  As  the  arsenical  ores,  often 
contain  sulphur,  a  little  sulphat  of  lead, 
may  be  mixed  with  the  arseniat ;  and  to 
decide  this,  digest  the  powder  in  warm 
dilute  muriatic  or  nitrous  acid,  and  the 
arseniat  will  be  dissolved,  leaving  the  sul- 
phat behind.  One  hundred  parts  of  arse- 
niat of  lead,  contain  oxide  of  lead  63,  wa- 
ter 4,  arsenic  acid  33,  which  are  equiva- 
lent to  22  of  the  metal. 

Arsenical  ores,  containing-  the  other  me. 
tals,  are  in  general,  distinguished  by  their 
respective  denominations.  The  arsenical 
pyrites,  or  marcasite,  contains  sulphur  and 
iron.  It  is  of  a  gray  ash  colour,  inclining 
to  blue,  either  solid,  or  composed  of  small 
brilliant  particles.  It  tarnishes  in  the  air, 
gives  fire  with  steel,  and  emits  a  smell  of 
garlic.  Sometimes  it  effervesces  with  the 
nitric  acid,  which  partly  dissolves  it.  In 
the  fire  it  is  volatilized,  and  forms  a  true 
realgar,  which  distinguishes  it  from  mis- 
pickle,  which  contains  iron  and  aisenic 
without  sulphur,  and  might  easily  be  con- 
founded with  it. 

OKKS  of  Bismuth.  Bismuth  is  the 
most  common  of  all  native  metallic  sub- 
stances. It  is  gene,  ally  found  either  in 
cubes  or  octagons,  or  of  a  dendritical  form, 
or  else  in  thin  laminae  investing  the  ores 
of  other  metals,  particularly  those  of  co- 
balt. As  it  is  very  fusible,  it  may  easily 
be  extracted  by  exposing  the  minerals, 
which  contain  it  to  a  gentle  heat.  It  then 


ORE 


ORE 


«xudesin  small  white  globules,  the  more 
readily  in  proportion  to  its  purity  It  effer- 
vesces with  nitric  acid,  forming-  a  solution 
at  first  milky,  but  which  afterward  be- 
comes clear.  It  is  said  to  be  sometimes 
alloyed  with  silver,  in  which  case  a  sepa- 
ration may  easily  be  made,  by  adding  wa- 
ter to  the  nitric  solution,  which  throws 
down  the  bismuth,  in  the  form  of  magis- 
tery. 

Oxide  of  bismuth,  is  found  of  a  whitish 
or  greenish-yellow  colour,  frequently  upon 
the  other  ores  of  bismuth,  probably  form- 
ed by  decomposition.  It  is  then  called 
flowers  of  bismuth,  and  may  be  distin- 
guished from  the  flowers  of  cobalt  by  the 
red  colour  of  the  latter  ;  for  the  flowers 
of  bismuth  are  never  red,  nor  become 
so.  This  oxide  is  readily  dissolved  in 
nitrous  acid,  and  may  be  precipitated  by 
water. 

The  oxide  of  bismuth  is  reducible  on 
charcoal,  by  the  blowpipe, and  melts  in  the 
spoon.  With  microcosmic  salt,  it  affords 
a  globule  of  a  dull  yellow  colour,  which 
becomes  paler,  and  rather  more  opake  by 
cooling.  With  borax,  a  mass  is  obtained 
in  the  spoon,  which  is  gray  upon  the  char- 
coal, and  not  easily  cleared  of  small  bub- 
bles. This  glass  fumes  when  kept  in  a 
State  of  fusion,  and  forms  a  circle  of  a 
greenish-yellow  colour  around  it,  produc- 
ed by  the  volatilization  of  part  of  the  bis- 
muth. 

Bismuth  is  mineralized  by  sulphur.  It 
resembles  galena  or  potters'  lead  ore,  in 
colour  and  appearance,  is  brittle,  easily 
cut  with  a  knife,  and  does  not  effervesce 
with  acids,  though  soluble  in  aqua  fortis. 
The  solution  is  clear,  and  sometimes 
greenish.  It  is  said  to  contain  also  cobalt 
and  arsenic,  but  Mongez  denies  the  latter. 
It  is  very  fusible,  and  the  sulphur  mostly 
separates  in  scorification.  There  are  two 
varieties  ;  the  one  tessular  like  galena, 
from  Bastnas  in  Sweden,  and  Schneeberg 
in  Saxony,  which  is  very  scarce  ;  the  other 
striated,  composed  of  scales  or  small  nee- 
dles, like  the  sulphureous  ore  of  antimony, 
but  does  not  soil  the  fingers.  It  comes 
from  Schneeberg  and  Johann-Georgens- 
tadt  in  Saxony. 

Before  the  blowpipe  this  ore  speedily 
melts,  and  affords  a  blue  flame,  with  a 
smell  of  sulphur,  but  the  perfect  reduc- 
tion is  rather  long  and  difficult.  Bergman 
advises  to  precipitate  the  bismuth  with  a 
small  quantity  of  cobalt,  which  penetrates 
the  globule,  by  virtue  of  the  sulphur.  The 
mass  then  swells  up,  and  produces  a  sco- 
ria, divided  into  very  evident  compart- 
ments. The  scoria,  kept  a  longer  time 
in  the  fire,  emits  globules  of  bismuth- 

Bismuth  is  also  found  mineralized  with 


sulphur  and  iron.  This  ore  is  composes 
ol  small,  thick,  uniform  scales,  of  a  gvay- 
yellowish  colour,  when  recently  broken, 
but  more  yellow  where  it  has  suffered  ex- 
posure to  the  air  This  species  is  more 
difficult  to  reduce,  than  the  preceding,  on 
account  of  the  iron  it  contains. 

Wallerius,  Sage,  and  Rome  de  Lisle, 
mention  an  ore  of  bismuth,  mineralized 
with  sulphur  and  arsenic,  which  is  of  a 
shining  appearance,  of  a  whitish-yellow,  or 
ash  colour,  composed  of  scales,  in  general 
small,  hard,  sometimes  giving  fire  with  a 
steel,  not  effervescent  with  ""nitric  acid, 
though  partly  soluble.  Mongez  is  dispos- 
ed to  think  it  merely  the  sulphureous  ore 
of  bismuth,  already  mentioned,  but  ob- 
serves, that  the  presence  of  arsenic  can- 
not but  show  itself,  by  its  peculiar  smell 
when  heated.    See  Bismuth. 

ORES  of  Cerum  are  not  much  known. 

ORES  of  Chrome.    See  Chrome. 

ORES  of  Cobalt.  Cobalt  has  not 
been  found  in  a  state  of  native  puritv,  but 
the  combination  of  this  semimetal  with 
arsenic  and  iron  in  the  metallic  form  usu- 
ally passes  for  such.  The  quantity  of  iron 
is  small.  This  ore  is  solid,  hard,  ponder- 
ous, of  a  gray  colour,  more  or  less  obscure, 
sometimes  inclining  to  red.  Its  fracture 
is  granulated,  not  unlike  some  kinds  of 
steel.  It  commonly  gives  fire  with  the 
steel,  and  emits  a  strong  smell  of  garlic. 
In  the  fire  it  becomes  black.  Nitric  acid 
dissolves  it  with  effervescence,  which  af- 
fords a  sympathetic  ink,  by  the  addition 
of  muriatic  acid. 

There  are  two  characters  which  readi- 
ly distinguish  this  mineral  from  the  white, 
and  gray  ores  of  arsenic. 

1.  It  forms  a  sympathetic  ink,  with  aqua 
regia;  and 

2.  It  affords  a  blue  glass  with  borax, 
whereas  that  of  the  ore  of  arsenic  is  black. 
There  are  two  varieties,  the  one  solid  and 
compact,  the  other  granulated  and  easily 
broken,  beside  that  its  colour  is  of  a 
reddish-white,  and  sometimes  a  little  he- 
pati. 

Before  the  blowpipe,  this  ore  first  emits 
a  strong  smell  of  garlic,  then  becomes 
black  and  melts  into  a  small  globule  of 
the  metal.  It  give  a  blue  colour  to  the 
fluxes. 

The  oxide  of  cobalt,  is  commonly  found 
in  the  earth  mixed  with  arsenic,  iron,  or 
copper ;  but  whether  mechanically,  or 
more  intimately  combined,  is  doubted  by 
Bergman.  It  is  usually  of  a  gray-black ; 
but  sometimes  so  black,  that  it  might  be 
taken  for  soot.  Il  soils  the  fingers,  and 
is  almost  always  friable  and  pulverulent. 
On  breaking  a  compact  specimen,  rose* 
coloured  spots  may  frequently  be  observ? 


ORE 


ORE 


ed,  resembling  the  flowers  of  cobalt.  It 
is  seldom  without  a  mixture  of  a  small 
portion  of  oxide  of  iron.  When  solid,  it 
sometimes  has  the  resemblance  and  form, 
of  a  vitreoas  scoria,  whence  some  minera- 
logists have  called  it  the  vitreous  ore  of 
cobalt,  or  slag.  These  are  free  from  sul- 
phur and  arsenic.  Cronstedt  compares 
the  friable  ore,  or  cobalt  ore,  to  the  arti- 
ficial zaffre.  Mongez  says,  it  contains 
clay. 

Before  the  blowpipe,  as  the  black  oxide 
of  cobalt  is  always  mixed  with  a  small 
portion  of  the  red  oxide,  which  is  arseni- 
cal, it  emits  a  slight  smell  of  garlic.  The 
redaction  is  very  difficult  But  it  dis- 
sohes  in  borax,  gives  it  a  blue  colour,  and 
is  partly  reduced  in  a  small  metallic  glo- 
bule, which  occupies  the  tower  part  of  the 
flux. 

The  arseniat  of  cobalt,  cobalt  bloom, 
or  red  cobalt  ore,  generally  occurs  mixed 
with  other  cobaii  ores,  or  as  a  covering 
to  them.  It  is  sometimes  found  in  crys- 
tallized quadrangular  prisms,  terminated 
by  dihedral  pyramids. 

Baron  Born,  mentions  a  sulphuret  of 
cobalt, in  external  characters,  very  like  the 
white  cobalt  ore,  but  perfectly  free  from 
arsenic  and  iron.  There  is  likewise  asul- 
phat  of  cobalt,  in  transparent  stalactitical 
crystals,  of  a  pale  red  colour. 

OltKS  of  Columbium,  are  not  much 
known. 

ORES  of  Copper.  Copper  is  not, 
•according  to  the  opinion  of  Bergman, 
found  native  without  a  mixture  of  gold, 
silver,  or  iron.  Some  specimens,  however, 
nearly  resemble  the  refined  copper  in  co- 
lour, malleability,  and  ductility.  Others, 
instead  of  possessing  the  reddish  colour, 
are  rather  of  a  yellow  or  brown  colour, 
with  green  or  blue  spots  of  rust. 

It  is  found  in  two  different  forms  :  1. 
Solid  native  copper,  which  is  either  crys- 
tallized or  in  grains,  or  thin  leaves,  threads 
or  dendrites,  adherent  to  diiferent  ma- 
trices, such  as  calcareous  stones,  spars, 
quartz,  petro-silex, jasper,  schistus.  There 
are  few  copper  ores,  according  to  Mon- 
gez,  which  do  not  contain  some  of  these 
varieties. 

2  Native  copper  in  the  form  of  small  j 
or   imperfectly  coherent  grains.  This 
copper  appears  to  have  been  deposited  j 
from  mineral  waters,  by  means  of  iron, 
for  which  reason  it  is  called  cement  cop-  ' 
Per.  /"      fY  , 

Kirwan  directs  the  humid  assay  of  na-  ' 
tive  copper,  by  nitric  acid.    The  gold,  if 
it  contain  any,  remains  undissolved  in  the  j 
form  of  a  black  powder,  which  may  be 
taken  up  and  examined  by  aqua  regia. 
The  silver  may  be  precipitated  from  the  j 

VOL.  IT. 


nitric  solution,  by  muriatic  acid,  or  bettel' 
by  copper  ;  and  the  iron  falls  down  in  the 
form  of  an  insoluble  oxide,  by  sufficient 
ebullition  with  water. 

The  oxided  copper  ores,  are  either  of  a 
red,  blue,  or  green  colour. 

The  red  copper  ore,  is  rather  scarce. 
In  some  specimens,  it  is  of  a  beautiful  red, 
or  of  a  brown-reddish  liver  colour,  whence 
it  has  obtained  the  name  of  hepatic  ore. 
When  in  a  loose  form,  it  is  called  copper 
ore ;  but  generally  it  is  moderately  hard, 
though  brittle,  sometimes  crystallized  and 
transparent,  either  in  a  capillary  form,  or 
in  cubes,  prisms,  or  pyramids.  Mongez 
says,  that  the  most  common  form,  is  that 
of  fine  grains,  resembling  the  flowers  of 
cinnabar.  It  is  easily  distinguished  by  its 
brightness,  and  ruddy  colour,  which  ap- 
proaches that  of  copper.  It  effervesces 
with  acids,  which  dissolve  it,  as  well  as 
the  other  oxides  of  copper.  Another  com- 
mon character  of  these  ores  is,  that  they 
blacken  in  a  moderate  heat,  to  which  may 
be  added,  the  property  of  affording  a  blue 
colour  with  ammonia. 

According  to  Fontana,  quoted  by  Kir- 
wan, a  hundred  parts  of  this  ore  contain 
seventy -three  of  copper,  twenty -six  of  car- 
bonic acid,  and  one  of  water.  Bergman 
also  found  it  to  contain  carbonic  acid.  Ac- 
cording to  Mr.  Chenevix,  however,  the  red 
octaedral  copper  ore  consists  of  a  pure 
oxide,  containing  88.5 per  cent,  of  metal; 
and  is  therefore  highly  valuable,  not  mere- 
ly  for  its  richness,  but  for  the  purity  of  the 
metal,  which  is  easily  obtained  from  it. 
The  brown  or  hepatic  ore  contains  a  va- 
riable proportion  of  iron  or  pyrites,  and 
sometimes  sulphuret  of  copper,  and  hence 
aflbrds  from  20  to  50  per  cent,  of  copper. 
It  is  often  iri-descent. 

The  blue  copper  ore,  most  frequently 
appears  in  a  loose  form,  though  some- 
times indurated  and  even  crystallized,  but 
it  is  then  mixed  with  quartz.  It  frequent- 
ly lines  the  internal  cavities  of  different 
matrices.  When  the  blue  colour  is  very 
lively,  it  is  called  azure  of  copper,  when 
pale?-,  mountain  blue,  and  when  abound- 
ing with  earthy  matter,  blue  chrysocolla* 
It  must  be  confessed,  however,  that  these 
terms  are  by  no  means  accurately  applied, 
but  taken  for  the  most  part  indiscrimi- 
nately. Morveau,  in  the  Memoirs  of  Di- 
jon, has  Inferred  from  experiment,  that 
the  oxides  of  copper  are  determined  to  a 
blue  rather  than  to  a  green,  by  a  neai-er 
approach  to  the  metallic  state  ;  but  on  this  * 
head,  see  Verdi  i  er. 

The  green  c  opper  ore,  is  distinguished 
by  the  names  mountain  green,  or  green 
chrysoc>lla."  It  is  found  in  two  states, 
either  earthy  and  friable,  of  a  more  or  le<s  - 
\  a 


ORE 


ORE 


deep  green,  or  else  solid  and  crystallized. 
The  must  beautiful  specimen  is  the  silky 
copper  ore,  so  called,  because  its  texture 
exhibits  long  shining-  filaments. 

The  solid  green  ore  is  usually  .called 
malachite. 

Analogous  to  the  oxided  copper  ores, 
is  the  lapis  armenus,  a  blue  stone,  that 
does  not  admit  Ot'a  polish,  and  consisting 
of  calcareous  earth  of  gypsum,  penetrat- 
ed with  the  blue  oxide  of  copper ;  hence 
it  sometimes  effervesces  with  acids,  and 
sometimes  not ;  but  never  gives  fire  with 
steel.  It  loses  its  colour  when  well  heat- 
ed in  the  fire.  This  stone  is  very  differ- 
ent from  the  lapis  lazuli,  since  this  last 
contains  no  copper. 

Bergman  from  Werner  mentions  a  cop- 
per ore,  consisting  of  that  metal  minera- 
lized by  carbonic  acid,  and  combined  with 
clay.  This  is  most  commonly  superficial, 
in  small  crystals  of  a  beautiful  green,  or 
in  small  scales,  and  was  formerly  consi- 
dered as  a  variety  of  mica  or  talc.  Nitric 
acid  dissolves  it  very  well,  and  the  solu- 
tion takes  a  gieen  colour.  The  copper 
may  be  precipitated  in  the  usual  manner. 
The  blowpipe  does  not  fuse  this  ore,  if 
the  flame  be  directed  against  its  fiat  sur- 
face ;  but  if  the  edge  be  attacked,  it  spee- 
dily melts  into  a  biack  scoria.  With  bo- 
rax it  affords  a  brown  yellow  glass,  and 
with  microcosmic  salt  a  glass  of  a  fine 
grass  green. 

Copper  mineralized  by  sulphur,  is  com- 
monly denominated  the  vitreous  copper 
ore.  Its  colour  is  red,  brown,  blue,  violet, 
or  gray  ;  it  is  generally  so  soft  as  to  be 
cut  with  a  knife,  and  shows  a  polished 
gold-coloured  surface  where  cut.  As  to 
form,  it  is  sometimes  crystallized  in  re- 
gular figures,  and  sometimes  irregular.  In 
its  fracture  it  often  shows  violet,  reddish, 
and  variable  colours.  It  is  much  more 
fusible  than  pure  copper,  and  may  be  melt- 
ed by  a  candle.  Its  specific  gravity  is  from 
4.129  to  5.338.  It  is  found  in  the  mines 
of  other  copper  ores,  and  in  the  lime-stone, 
spar,  quartz,  mica,  and  clay  ;  it  is  the 
richest  of  all  the  copper  ores,  and  the  gray 
affords  sometimes,  from  80  to  90  percent, 
of  copper,  10  or  12  of  sulphur,  with  a  small 
proportion  of  iron :  the  red  ores  are  the 
poorest,  containing  most  iron. 

This  ore  may  be  reduced  with  consider- 
able facility,  by  the  blowpipe,  but  it  is  not 
easy  to  scorify  and  separate  the  last  por- 
tions of  iron  and  sulphur.  To  analyse  the 
ore,  Bergman  advises  a  solution  of  it  in 
five  times  its  weight,  of  concentrated  sul- 
phuric acid  by  ebullition,  to  dryness,  and 
the  subsequent  addition  of  as  much  water, 
as  will  dissolve  the  sulphat  thus  formed. 
This  solution  he  precipitates,  by  a  clean 


bar  of  iron,  and  thus  obtains  the  copper  in 
its  metallic  form.  If  the  solution  be  con- 
taminated with  iron,  he  redissolves  the 
impure  copper  thus  obtained,  in  the  same 
manner,  and  so  procures  a  rich  solution  ; 
which  he  again  precipitates  with  iron. 

The  variegated  copper  ore,  differs  from 
the  vitreous  ore,  only  in  containing  more 
iron,  of  which  the  proportion  is  from  20 
to  50  per  cent.  Its  colour  consists  of  va- 
rious shades  of  blue,  or  reddish  blue.  It 
is  as  hard  or  harder,  than  the  preceding, 
and  its  fracture  is  reddish,  and  polished 
like  glass.  It  is  more  difficultly  reduced 
by  the  blowpipe,  and  may  be  analysed 
in  the  humid  way,  by  the  same  treat- 
ment. 

The  yellow  copper  ore,  or  copper  py- 
rites, contain  a  large  proportion  of  iron, 
mineralized  with  sulphur.  It  is  sometimes 
found  crystallized,  and  sometimes  irregu- 
larly formed.  The  crystallized  sort  con- 
tains the  smallest  portion  of  copper,  which 
is  sometimes  so  trifling,  that  the  ore  may 
be  considered  as  a  martial  pyrites,  though 
an  experienced  eye,  may  discern  a  differ- 
ence between  them.  The  copper  scarce- 
ly exceeds  40  per  cent,  in  any  of  the  spe- 
cimens. 

When  this  metal  is  sufficiently  abun- 
dant, to  be  wrought  with  profit,  it  may  be 
roasted,  and  the  sulphur  preserved  to- 
ward  defraying  the  expenses.  The  resi- 
due being  exposed  to  the  united  action 
of  air  and  water,  in  a  proper  situation,  will 
afford  the  sulphat  of  copper,  which  may 
either  be  crystallized  for  sale,  or  pi-ecipi- 
tated  by  fragments  of  old  iron,  as  is  ad- 
vantageously done  at  the  Paris-mountain 
mine,  in  the  isle  of  Anglesea,  and  else- 
where. When  rich  in  copper,  it  is  a  bril- 
liant yellow  colour,  sometimes  approach- 
ing to  red ;  in  other  samples  it  is  greenish, 
from  the  admixture  of  these  two  colours. 
The  colours  are  more  neat  and  lively,  at 
the  place  of  fracture,  than  after  exposure 
to  the  air,  which  changes  them.  It  is  not 
very  hard,  is  considerably  brittle,  and 
scarcely  gives  fire  with  the  steel.  Its  fria- 
bility is  greater,  the  larger  the  proportion 
of  sulphur,  and  the  less  of  iron.  It  affords 
several  varieties. 

1.  Yellow  copper  ore,  which  is  solid, 
ponderous,  brilliant,  and  close  in  its  frac- 
ture. 

2  The  yellow  ore,  which,  though  hard, 
has  a  laminated  fracture  ;  this  is  the  most 
common  of  any. 

3.  Green  yellowish  copper  ore ;  it  con- 
tains the  largest  portion  of  sulphur,  and 
the  least  ot  iron. 

4.  Crystallized  yellow  copper  ore;  it  is 
the  copper  pyrites,  properly  so  called, 
containing  the  least  proportion  of  copper, 


ORE 


ORE 


and  the  most  of  iron.  When  this  is  met 
with  among-  rich  ores,  it  is  thrown  aside, 
because  of  Us  difficult  reduction  and  small 
produce,  which  does  not  exceed  four  or 
live  pounds  of  copper,  in  the  hundred 
weight  of  ore.  Its  colour  varies,  being 
sometimes  reddish,  or  resembling-  a  pi- 
g-eon's neck ;  when  yellow,  it  is  paler  than 
the  first  variety  here  mentioned  The 
management  of  this  ore  in  the  analysis, 
may  be  gathered  from  what  has  already 
been  said  It  may  be  readily  fused  by 
the  blowpipe  into  a  black  matt,  but  it  re- 
quires a  continuance  of  the  heat  for  a 
long  time,  before  the  globule  of  copper 
becomes  disengaged. 

The  gray  copper  ore,  appears  to  owe 
its  character  to  antimony,  which  exists  in 
it  together  with  iron  and  sulphur.  It 
sometimes  contains  silver,  and  a  large 
proportion  of  lead.  The  copper  amounts 
to  between  sixteen  and  thirty-two  parts  in 
the  hundred. 

The  colour  of  this  ore  is  an  obscure  or 
blackish  gray  :  it  is  hard,  and  the  antimony 
it  contains,  renders  it  brittle- 

The  count  de  Bournon  and  Mr.  Chene- 
vix,  have  lately  described  and  analysed 
with  great  minuteness,  various  arseniats 
of  copper. 

1.  Crystallized  in  obtuse  octaedra  ;  of 
a  beautiful  deep  sky  blue,  sometimes  in- 
clining to  Prussian  blue,  frequently  a  fine 
grass  or  apple  green,  and  sometimes  near- 
ly white,  with  a  blue  cast.  Specific  gra- 
vity 2.881. 

2.  In  hexaedral  laminee  ;  generally  of  a 
fine  deep  emerald  green,  but  sometimes 
lighter.    Specific  gravity  2.548 

3.  In  acute  octaedra  ;  of  a  brown  or  bot- 
tle green.  Specific  gravity  4.210.  Of  this 
there  are  several  varieties,  in  one  of 
which,  the  amianthiform,  the  colour  varies 
through  different  shades  of  a  green  to  a 
golden  brown,  straw  colour,  and  even  sa- 
tiny white- 

4.  In  trihedral  prisms ;  of  a  blueisii 
green,  or  deep  verdlgrise  colour,  but  easi- 
ly decomposed,  and  then  turning  black  on 
the  outside.    Specific  gravity  4.28 

The  third  species  above  mentioned  gave 
Mr.Chenevix  60  per  cent,  oxide  of  copper, 
39  7  arsenic  acid  The  rest  appeared  to  be 
ars -mated  hydrats  of  copp  r,  containing 
from  14  to  29  per  cent-  arsenic  acid,  and 
from  1 6  to  35  water. 

There  is  a  bituminous  copper  ore,  or  pit- 
coal,  containing  copper,  which  is  found  in 
Sweden,  Ifmgary,  and  Alsatia.  It  takes 
fire  without  much  difficulty,  burns  siowly, 
and  leave  >  ashes,  from  which  copper  is 
extracted  This  is  probably  the  same  sub- 
stance mentioned  by  Brunnich  on  Cron- 
fitexit,  p.  698,  which  is  called  pitch  ore,  in 


the  Bannat  of  Temcswar.  Gellert,  in  his 
Metallurgy  Chemistry,  mentions  a  copper 
ore  of  the  colour  of  pitch,  which  resem- 
bles a  vitrified  scoria,  and  Raspe  informs 
us,  that  copper  has  been  found  in  Corn- 
wall, mixed  with  black  pitchy  rock  oil. 

Copper  is  also  obtained  from  waters  in 
which  it  is  combined  with  the  sulphuric 
and  sometimes  with  the  muriatic  acid,  no 
doubt  produced  by  the  decomposition  of 
some  of  the  ores  above  mentioned.  Animal 
and  vegetable  substances  are  sometimes 
found  penetrated  with  copper. 

AVe  shall  conclude  this  article  by  in- 
serting some  processes  for  the  reduction 
of  copper  ores  in  the  furnaces,  taken 
from  Cramer. 

Process  I. 

To  reduce  and  precipitate  copper  from  a 
pure  and  fusible  ore  in  a  close  vessel. 

Mix  one,  or,  if  you  have  small  weights, 
two  docimastical  centners  of  ore,  beaten 
extremely  fine,  with  six  centners  of  the 
black  flux ;  and  having  put  them  into  a 
crucible  or  pot,  cover  them  one  inch  high 
with  common  salt,  and  press  them  down 
with  your  finger:  but  let  the  capacity  of 
the  vessel  be  such,  that  it  may  be  only 
half  full ;  shut  the  vessel  close,  put  it  in- 
to the  furnace,  heap  coals  upon  it  so  that 
it  may  be  covered  over  with  them  a  few 
inches  high  ;  govern  the  fire  in  such  a 
manner,  that  it  may  at  first  grow  slightly- 
red-hot;  soon  after  you  will  hear  the  com- 
mon salt  crackle,  which  will  be  followed 
by  a  gentle  hissing  noise.  As  long  as  this 
lasts,  keep  the  same  degree  of  fire  till  it 
ceases.  Then  suddenly  increase  the  fire, 
either  with  the  funnel  and  cover  put  upon 
the  furnace,  or  with  a  pair  of  bellows  ap- 
plied to  the  hole  of  the  bottom  part,  that 
the  vessel  may  become  strongly  ignited. 
Thus  you  will  reduce  and  precipitate 
your  copper  in  about  a  quarter  of  an 
hour:  then  take  out  the  vessel,  and  strike 
with  a  few  blows  the  pavement  upon 
which  you  put  it,  that  all  the  small  grains 
of  copper  may  be  collected  into  one  mass. 

Break  the  vessel,  when  grown  cold,  in 
two,  from  top  to  bottom,  as  nearly  as  you 
can:  if. the  whole  process  has  been  well 
performed,  you  will  find  a  solid,  perfectly 
yellow,  and  malleable  button  adhering  to 
the  bottom  of  the  vessel,  with  scoriae  re- 
maining at  top  of  a  brown  colour,  solid, 
hard,,  and  shining,  from  which  the  button 
must  be  separated  by  several  gentle  blows 
of  a  hammer :  when  this  is  done,  weigh 
it,  after  having  wiped  off  all  the  impuri- 
ties. 

A  soft,  dusty,  and  very  black  scoria  is 
a  sign  the  fire  was  not  sufficiently  strong. 


ORE 


ORE 


Small  neat  grains  of  copper  reduced,  but 
not  precipitated,  and  adhering  still  to  sco- 
riae, especially  not  very  far  from  the  bot- 
tom, and  an  unequal  and  ramified  button, 
are  signs  of  the  same  thing  A  solid,  hard, 
shining,  red-coloured  scoria,  especially 
about  the  button,  or  even  the  button  it- 
self, when  coloured  with  a  like  small 
crust,  are  signs  of  an  excess  in  the  degree 
and  duration  of  the  fire. 

Remarks.  All  the  ores  which  are  easily 
melted  in  the  fire,  are  not  the  objects  of 
this  process ;  for  they  must  also  be  very 
pure.  Such  are  the  vitreous  copper  ores  ; 
but  especially  the  green  and  azure -colour- 
ed ores,  and  the  caeruleum  and  viride 
montanum,  which  are  not  very  different 
from  them.  But  if  there  be  a  great  quan- 
tity of  arsenic,  sulphur,  or  of  the  ore  of 
another  metal  and  semimetal,  joined  to 
the  ore  of  copper,  then  you  will  never  ob- 
tain a  malleable  button  of  pure  copper, 
though  ores  are  not  always  rendered  re- 
fractory by  the  presence  of  these. 

Process  II. 

To  reduce  and  precipitate  copper  out  cj 
ores  rtnd.red  reft  ctory  by  earth  and 
stones  that  cannot  be  washed  off 
Beat  your  ore  into  a  very  subtile  pow- 
der, of  which  weigh  one  or  two  centners, 
and  mix  as  much  sandiver  with  them. 
This  done,  add  four  times  as  much  of  the 
black  flux  with  respect  to  the  ore;  for  by 
this  means  the  infusible  terrestrial  parts 
are  better  disposed  to  scorificaiior,,  and 
the  reducing  flux  may  act  more  freely 
upon  the  metallic  particles,  set  at  liberty 
As  for  the  rest,  proceed  as  in  the  last 
process:  but  you  must  take  the  fire  a  lit- 
tle stronger  for  about  half  an  hour  toge- 
ther. When  the  vessel  is  grown  cold 
and  broken,  examine  the  scorix,  whether 
they  be  in  the  state  1  hey  ought  to  be.  The 
button  will  be  as  line  and  ductile  as  the 
foregoing. 

Remark.  As  these  copper  ores  contain 
scarcely  any  sulphur  or  arsenic,  the  roast- 
ing would  be  of  no  effect,  and  much  cop- 
per would  be  lost.  For  no  metallic  ox- 
ide, except  those  of  gold  and  siher,  im- 
properly so  called,  can  be  roasted  without 
some  loss  of  the  metal 

Pkocess  III. 

To  precipitate  copper  out  of  an  ore  that  con- 
tains troth 

Act  in  every  respect  according  to  the 
last  process  But  you  will  find,  after  the 
vessel  is  broken,  a  button  by  no  means 
so  fine,  but  less  ductile,  wherein  the  ge- 
nuine colour  of  the  copper  does  not  per- 


fectly appear,  and  which  must  be  farther 

purified. 

Remarks.  The  fire  used  in  this  opera- 
tion is  not  so  strong  as  to  reduce  and  fuse 
iron  alone.  But  copper  dissolves  iron  in 
the  dry  way,  though  of  itself  very  refrac- 
tory in  the  fire.  And  for  this  reason, 
while  the  ore  and  the  flux  are  most  inti- 
mately mixed  and  confounded  by  tritura- 
tion, the  greater  part  of  t  he  iron  will  com- 
bine with  the  copper  in  its  metallic  state. 

Process  IV. 

The  roasting  of  pyritose,  sulphureous,  arse- 
nical, semimetallit  copper  ort. 

Break  two  docimastical  centners  of  the 
ore  to  a  coarse  powder,  put  them  into  a 
test  covered  with  a  tile,  and  place  them 
under  the  muffle  of  a  docimastical  fur- 
nace. The  fire  must  be  so  gentle,  that 
the  muffle  may  be  but  faintly  red-hot  i 
when  the  ore  has  decrepitated,  open  the 
test,  and  continue  the  fire  for  a  few  mi- 
nutes ;  then  increase  it  by  degrees,  that 
you  may  see  the  ore  perpetually  smoking 
a  little :  in  the  mean  time,  it  is  also  pro- 
per now  and  then  to  stir  it  up  with  an 
iron  hook  The  shining  particles  will  as- 
sume a  dark  red  or  blackish  colour.  This 
done,  take  out  the  test,  and  let  it  grow 
cold.  If  the  small  grains  be  neither  melt- 
ed, nor  strongly  adherent  to  each  other, 
the  process  has  been  well  conducted :  but 
if  they  run  again  into  one  single  cak( ,  it 
must  be  repeated  with  another  portion  of 
the  ore,  in  a  more  gentle  fire- 

When  the  ore  is  grown  cold,  beat  it  to 
a  powder  somewhat  finer,  and  roast  it  by 
the  same  method  as  before ;  then  take  it 
out,  and  if  the  powder  be  not  yet  melted, 
beat  it  again  to  a  very  subtile  powder  j 
in  this  you  are  to  take  care  that  nothing 
is  lost. 

Roast  the  powder  in  a  fire  somewhat 
stronger,  but  for  a  few  minutes  only.  If 
you  do  not  then  find  the  ore  in  any  respect 
inclined  to  melt,  add  a  little  tallow,  and 
burn  it  awaj  under  the  muffle,  and  repeat 
the  operation,  till,  the  fire  being  very- 
bright,  you  no  longer  perceive  any  sul- 
phureous, arsenical,  unpleasant  smell,  or 
any  smoke;  and  there  remains  nothing 
but  a  fine  soft  powder  of  a  dark  red,  o** 
blackish  colour. 

Remarks  Every  pyrites  contains  iron 
with  an  unmetallic  earth,  with  sulphur,  or 
.arsenic,  nnd  most  commonly  both  Be- 
sides, as  the  copper  in  pyrites  is  exceed- 
ingly variable  in  quantity,  their  disposi- 
tion in  the  fire  must  vary  accordingly  For 
instance,  the  more  copper  there  is  in  py- 
rites, the  more  it  inclines  to  c<  lliquation. 
The  more  sulphur  and  arsenic  it  contains., 


ORE 


the  more  fusible  it  will  be  ;  and  the  more 
iron  and  unmetallic  earth  it  contains,  the 
more  refractory  it  will  prove  in  the  fire. 

If  such  pyrites  melt  in  the  roasting,  as 
is  the  case  with  some  of  them,  or  if  they 
grow  but  red-hot,  the  sulphur  and  arse- 
nic become  so  strictly  united  to  the  fixed 
part,  that  it  is  almost  impossible  to  dissi- 
pate them.  For  in  this  case,  when  the 
matter  is  again  reduced  into  a  powder,  a 
much  greater  time  and  accuracy  are  re- 
quired in  the  management  of  the  fire  to 
perform  the  operation.  For  this  reason, 
it  is  much  better  to  repeat  it  with  new 
pyrites.  But  you  must  roast  no  more  than 
twice  the  quantity  at  once  of  die  ore  you 
are  inclined  to  employ  in  the  foregoing 
experiment ;  in  order  that,  if  the  precipi- 
tation by  fusion  should  not  succeed,  there 
may  still  remain  another  portion  for  use, 
instead  of  your  being  obliged  to  repeat  a 
tedious  roasting. 

If  you  observe  the  signs  of  a  ferrugi- 
nous refractory  pyrites,  the  operation 
must  be  performed  with  a  stronger  fire, 
and  with  much  greater  speed.  However, 
you  must  be  careful  not  to  perform  it  with 
too  violent  a  fire :  for  a  large  proportion 
of  copper  is  destroyed  not  only  by  the 
arsenic  but  by  the  sulphur ;  and  this  hap- 
pens even  in  vessels  nearly  closed,  when 
the  sulphur  is  expelled  by  a  fire  not  quite 
so  strong.  By  repeated  and  gentle  sub- 
limation of  the  sulphur  in  a  vessel,  both 
very  clean  and  well  closed,  this  faot  will 
be  clearly  seen. 

When  the  greater  part  of  the  sulphur 
and  the  arsenic  is  dissipated,. you  may 
make  a  stronger  fire;  but  then  it  is  pro- 
per to  add  alittle  fat.  Cramer  here  ac- 
counts for  the  advantage  produced  by  the 
fat,  by  observing,  that  it  dissolves  mineral 
sulphur.  In  fact,  it  reduces  and  volatil- 
izes the  last  portions  of  arsenic,  and  at 
the  same  time,  as  he  justly  remarks,  pre- 
vents that  extreme  scorification  of  the 
copper,  which  would  greatly  impede  its 
subsequent  reduction.  Hence  he  adds, 
the  reason  is  plain,  why  ass;iyers  produce 
less  metal  m  the  trying  of  veins  of  copper, 
lead,  and  tin,  than  skilful  smelters  do  in 
large  operations  For  the  former  perform 
the  roaming  under  a  muffle,  with  a  clear 
fire,  and  without  any  oily  reducing  mat- 
ter; whereas  the  latter  perform  it  in  the 
middle  of  charcoal  or  of  wood,  which 
constantly  tend  to  reduce  the  oxides. 

The  darker  and  blacker  the  powder  of 
the  roasted  ore  appears,  the  more  copper 
you  may  expect  from  it.  But  the  redder 
it  looks,  the  less  copper  and  the  more  iron 
it  affords  ;  for  roasted  copper  dissolved 
by  sulphur,  or  the  acid  of  it,  is  very- 


black  ;  and  iron,  on  the  contrary,  very* 
red. 

Process  V. 

The  precipitation  of  copper  out  of  rua&tcd 
ore  of  the  last  process. 
Divide  the  roasted  ore  into  two  parts, 
and  reckon  each  of  them  a  centner:  add 
to  it  the  same  weight  of  sandiver,  and  four 
times  as  much  of  the  black  flux,  and  mix 
them  well  together.  Manage  the  rest  of 
the  operation  in  every  respect  according 
to  process  I.  The  precipitated  button  will 
be  slightly  malleable,  sometimes  brittle, 
now  and  then  very  much  like  pure  copper 
in  its  colour,  but  sometimes  whitish,  and 
even  blackish.  Whence  it  is  most  com- 
monly called  black  copper,  though  it  is 
not  always  of  so  dark  a  colour. 

It  is  easy  to  conceive,  that  there  is  as 
great  a  difference  between  the  several 
kinds  of  the  metal  called  black  copper,  as 
there  is  between  the  pyritose  and  other 
copper  ores  accidentally  mixed  with  other 
metallic  and  semimetallic  bodies.  For  all 
the  metals,  the  ores  of  which  are  inter- 
mixed with  the  copper  ores,  being  reduc 
ed,  are  precipitated  together  with  the 
copper;  which  is  brought  about  by  means 
of  the  black  flux.  Hence,  iron,  lead,  tin, 
antimony,  bismuth,  are  most  commonly 
mixed  with  black  copper  in  a  variety  of 
different  proportions. 

Indeed,  it  is  self  evident,  that  gold  and 
silver,  which  are  dissolvable  by  all  these 
matters,  are  collected  in  such  a  button, 
when  they  have  previously  existed  in  the 
ore.  And  moreover,  sulphur  and  arsenic 
are  not  always  entirely  absent.  For  they 
can  hardly  be  expelled  so  perfectly,  by  the 
many  preceding"  roastings,  but  there  will 
remain  some  vestiges  of  them,  which  are 
not  dissipated  by  a  sudden  melting',  espe- 
cially in  a  close  vessel,  wherein  the  flux 
swimming  at  top  hinders  the  action  of  the 
air.  Indeed,  arsenic  is  rather  fixed  by  the 
black  flux,  and  assumes  a  semimetallic 
form,  while  it  is  at  the  same  time  preserv  - 
ed from  dissipating  by  the  copper. 

Process  VI. 

To  reduce  black  copper  into  pure  copper  by 
scorification. 
Separate  a  specimen  of  your  black  cop. 
per,  of  the  weight  of  two  docimastical 
centners  at  least ;  and  perform  this  in  the 
same  manner,  and  with  the  same  precau- 
tions, as  if  you  would  detect  a  quantity 
of  silver  in  black  copper. 

Then  with  lute  and  coal-dust  make  a 
bed  in  the  cavity  of  a  moistened  test: 


ORE 


ORE 


when  this  bed  is  dry,  put  it  under  the  muf- 
fle of  a  docimasticai  furnace,  in  the  open 
orifice  of  which  there  must  be  bright 
burning  coals,  with  which  the  test  must 
likewise  be  on  all  putts  surrounded. 
When  the  whole  is  perfectly  red-hot,  put 
your  copper  into  the  fire  alone,  if  it  con- 
tain lead  ;  but  if  it  be  entirely  deprived  of 
it,  add  a  small  quantity  of  glass  of  lead, 
and  with  a  pair  of  hand-bellows  increase 
the  fire,  that  the  whole  may  speedily 
melt :  this  done,  let  the  fire  be  made  a  lit- 
tle less  violent,  and  such  as  will  be  suffi- 
cient to  keep  the  metallic  mass  well  melt- 
ed, and  not  much  greater.  The  melted 
mass  will  boil,  and  scoriae  will  be  pro- 
duced, that  will  gather  at  the  circumfer- 
ence. All  the  heterogeneous  matters  be- 
ing at  last  partly  dissipated,  and  partly 
turned  to  scorise,  the  surface  of  the  pure 
melted  copper  will  appear. 

As  soon  as  you  perceive  this,  take  the 
pot  out  of  the  fire,  and  extinguish  it  in 
water  :  then  examine  it  in  a  balance ;  and 
if  lead  has  been  at  first  mixed  with  your 
black  copper,  add  to  the  button  remain- 
ing of  the  pure  copper,  one  fif.eenth  part 
of  its  weight  which  the  copper  has  lost  by 
means  of  the  lead ;  then  break  it  with  a 
vice  ;  and  thus  you  will  be  able  to  judge 
by  its  colour  and  malleability,  and  by  the 
surface  of  it,  after  it  is  broken,  whether 
the  purifying-  of  it  has  been  well  perform- 
ed or  not.  But  whatever  caution  you 
may  use  in  the  performing  of  this,  process, 
the  product  will  notwithstanding  be  al- 
ways less  in  proportion  than  what  you  can 
obtain  by  a  larger  operation,  provided  the 
copper  be  well  purified  in  the  small  trial. 

Remarks.  This  is  the  last  purifying  of 
copper,  whereby  the  separation  of  the  he- 
terogeneous bodies,  begun  in  the  forego- 
ing" process,  is  completed  as  perfectly  as 
it  possibly  can  be.  For,  except  gold  and 
silver,  all  the  other  metals  and  semime- 
tals  are  partly  dissipated  and  partly 
burnt,  together  with  the  sulphur  and  arse- 
nic. For  in  the  fusion  they  either  turn  of 
themselves  to  scoria  and  fumes,  or  this  is 
performed  by  means  of  iron,  which  chiefly 
absorbs  semimeials,  sulphur  and  arsenic, 
and  at  the  same  time  they  accelerate  its 
destruction.  Thus  the  copper  is  precipi- 
tated out  of  them  pure :  for  it  is  self-evi- 
dent, that  the  unmetallic  earth  is  expell- 
ed, the  copper  being  reduced  from  a  vi- 
trescent  earthy  to  a  metallic  state ;  and 
the  arsenic  being  dissipated,  by  means  of 
which  the  said  earth  has  been  joined  to 
the  coarser  buttons  of  the  first  fusion. 
But  there  is  at  the  same  time  a  considera- 
ble quantity  of  the  copper  that  mixes  with 
the  scoria,  though  a  great  part  of  it  may 


be  reduced  out  of  them  by  repeating  the 

fusion. 

The  fire  in  this  process  must  be  applied 
with  all  possible  speed,  to  make  it  soon 
run  :  for,  if  you  neglect  this,  much  of 
your  copper  is  burnt ;  because  copper  that 
is  only  red-hot  cleaves  much  sooner,  and 
in  much  greater  quantity,  into  half-scori- 
fied scales,  than  it  is  diminished  in  the 
same  time  when  melted.  However,  too 
impetuous  a  fire,  and  one  much  greater 
than  is  necessary  for  its  fusion,  destroys  a 
much  greater  quantity  of  it  than  a  fire'on- 
ly  sufficient  to  fuse  it.  For  this  reason} 
when  the  purifying  is  finished,  the  melted 
body  must  be  extinguished  in  water  toge- 
ther with  the  vessel,  lest,  being  already 
grown  hard,  it  should  still  remain  hot  for 
a  while;  which  must  be  done  very  care- 
fully to  prevent  dangerous  explosions. 

The  scoria  of  the  above  process  fre- 
quently contains  copper.  To  extract 
which,  let  two  or  three  docimastical  cent- 
ners of  the  scoria,  if  it  be  charged  with 
sulphur,  be  beaten  into  a  subtile  powder, 
and  mix  it,  either  alone,  or,  if  its  refracto- 
ry nature  require  it,  with  some  very  fusi- 
ble, common,  pounded  glass,  without  a 
reducing  saline  flux,  and  melt  it  in  a  close 
vessel,  and  in  a  fire  having  a  draught  of 
air;  by  which  you  will  obtain  a  button. 

But  when  the  scoria  has  little  or  no  sul- 
phur at  all  in  it,  take  one  centner  of  it, 
and  with  the  black  flux  manage  it  as  you 
do  the  fusible  copper  ore  (process  1.)  ;  by 
which  you  will  have  pure  metal. 

Process  VII. 

To  assay  Copper  ores. 
Roasl  a  quintal  of  ore  (after  the  man- 
ner described  in  process  IV  ) ;  add  to  it 
an  equal  quantity  of  borax,  half  a  quintal 
of  fusible  glass,  and  a  quarter  of  a  quin- 
tal of  pitch  :  put  the  mixture  in  a  cruci- 
ble, the  inner  surface  of  which  has  been 
previously  rubbed  with  a  fluid  paste  of 
charcoal-dust  and  water ;  cover  the  whole 
with  pounded  glass  mixed  with  a  little  bo- 
rax, or  with  decrepitated  sea-salt;  put  a 
lid  on  the  crucible,  which  you  will  place 
in  an  air  furnace,  or  in  a  blast  furnace  : 
when  the  fire  shall  have  extended  to  the 
bottom  of  the  coals,  let  it  be  excited  brisk- 
ly during  half  an  hour,  that  the  crucible 
may  be  of  a  brisk  red  colour ;  then  with- 
draw the  crucible,  and  when  it  is  cold 
break  it ;  observe  if  the  scoria  be  well 
made:  separate  the  button,  which  ought 
to  be  semiductile,  and  weigh  it.  This  but- 
ton is  black  copper,  which  must  be  puri- 
fied as  in  process  VI. 
If  the  ore  be  very  poor,  and  enveloped 


ORE 


ORE 


in  much  earthy  and  stony  matters,  to  a 
quintal  of  it,  a  quintal  and  a  half  of  borax, 
a  quarter  of  a  quintal  of  pitch,  and  ten 
pounds  of  oxide  of  lead  or  minium,  must 
be  added.  The  oxide  of  lead  will  be  re- 
vived, and  will  unite  with  the  scattered 
particles  of  the  copper,  and  together  with 
these  will  fall  to  the  bottom  of  the  cruci- 
ble, forming  an  alloy.  When  the  ores  of 
copper  are  very  rich,  half  a  quintal  of  bo- 
rax, and  a  quarter  of  a  quintal  of  glass 
will  be  sufficient  for  the  reduction.  If  the 
ore  be  charged  with  much  antimony,  a 
half  or  three  quarters  of  a  quintal  of  iron 
filings  may  be  added;  otherwise  the  large 
quantity  of  antimony  might  destroy  the 
copper,  especially  if  the  ore  contained  no 
lead.  If  iron  be  contained  in  copper  ore, 
as  in  pyrites,  some  pounds  of  antimony, 
or  of  its  suiphurct,  may  be  added  in  the 
assay;  as  these  substances  more  readily 
unite  with  iron  than  with  copper,  and 
therefore  disengage  the  latter  metal  from 
the  former. 

Ores  of  Gold. 
From  the  unchangeableness  of  gold  by 
the  solvents  usually  disengaged  in  nature, 
it  is  comparatively  very  seldom  found  but 
in  the  native  state.  In  this  state  it  is  never 
absolutely  pure,  but  always  mixed  either 
with  silver,  copper,  or  iron.  It  is  usually 
found  in  rocks  of  quartz,  always  in  small 
particles  or  masses.  The  sands  of  several 
rivers  afford  it  in  small  plates  or  leaves. 
Most  great  rivers  carry  gold  with  them, 
even  such  as  do  not  take  their  rise  in 
mountains  where  gold  is  found.  In  the 
south  of  France,  in  Transylvania,  and  else- 
where in  Europe,  this  gold  is  separated 
by  washing  off  the  sand ;  but  the  produce 
is  not  sufficient  in  general  to  pay  any  rent, 
or  employ  capital.  It  merely  affords  sub- 
sistence to  such  poor  families  as  apply  to 
this  species  of  industry,  particularly  after 
the  torrents  occasioned  by  heavy  rains. 
If  a  hundred  pounds  of  sand  contain  twen- 
ty four  grains  of  gold,  it  is  said  the  sepa- 
ration is  worth  attending  to;  but  in  Afri- 
ca, five  pounds  of  sand  often  contain  sixty- 
three  grains  of  gold.  The  heaviest  sand, 
which  is  often  black  or  red,  yields  most. 

liaubenton  distinguishes  eight  varieties 
of  native  gold. 

1.  In  powder. 

2.  In  grains. 

3.  In  small  spangles. 

4.  In  masses. 

5.  In  filaments. 

6.  In  branches  like  vegetables. 

7.  In  small  plates  ;  and 

8.  In  octaedral  crystals. 

Gold  is  found  mineralized  by  sulphur 
together  with  iron,  which  is  supposed  to 


be  the  connecting  medium.  This  is  the 
auriferous  pyrites.  It  is  close  and  com- 
pact, of  a  brighter  and  more  lively  yellow 
than  the  ordinary  pyrites  ;  notwithstand- 
ing which,  they  are,  as  Mongez  says,  very 
difficult  to  be  distinguished.  The  gold 
cannot  be  extracted  by  aqua  regia,  or  by 
amalgamation,  but  the  last-mentioned  au- 
thor gives  the  following  simple  method 
for  this  purpose :  Take  a  small  quantity 
of  this  pyrites,  and  digest  it  in  the  nitric 
acid.  All  the  foreign  matters  will  be  dis- 
solved, except  the  g  Id  and  sulphur, 
which  will  fall  to  the  bottom.  Wash  the 
residue  under  water  till  nothing  more  re- 
mains but  a  yellow  brilliant  powder.  This 
is  the  gold.  According  to  Mr.  Sage,  one 
half  as  much  more  gold  is  extracted  from 
the  pyrites  by  this  method  than  by  treat- 
ment with  lead. 

This  pyrites,  according  to  Cronstedt, 
sometimes  contains  an  ounce  of  gold  in 
the  hundred  pounds.  Some  samples  con- 
tain a  portion  of  zinc  as  well  as  iron,  and 
even  copper,  which  gives  the  mass  a 
greenish  tinge.  It  is  found  at  Adelfors 
in  Sweden,  in  Hungary,  Mexico,  the  island 
of  Sumatra,  Switzerland,  and  Dauphiny  in 
France.  Cronstedt  remarks,  that  no  py- 
rites ought  to  be  despised  which  are  found 
in  tracts  where  gold  ores  are  obtained. 
Brunnich  on  Cronstedt  affirms,  that  the 
Transylvanian  gold  pyrites,  in  which  no 
gold  can  be  discovered  by  the  eye,  con- 
tained from  fifty  to  one  hundred  and  ten 
ounces,  and  upwards,  in  the  hundred 
weight;  and  that  those  where  the  gold 
appears  in  the  pyrites  like  mixed  Spanish 
snuff,  contained  two  hundred  and  fifty 
ounces,  but  they  are  very  scarce. 

Gold  is  found  in  Hungary  united  with 
mercury  and  sulphur.  It  is  the  auriferous 
cinnabar. 

There  is  likewise  a  blend  or  ore  of  zinc 
found  at  Chemnitz  in  Hungary,  which 
contains  silver  and  gold.  It  is  usually  cf 
a  red  or  black  colour. 

The  auriferous  ore  of  Nagayac  in  Tran- 
sylvania is  mentioned  by  Bergman  as  a 
compound  of  gold,  silver,  lead,  and  iron, 
mineralized  by  sulphur.  The  ore  is  of  a 
gray  colour,  more  or  less  obscure,  in  ir- 
regular masses ;  but  sometimes,  also,  it 
is  composed  of  slender,  flexible  leaves  of 
no  great  consistency ;  it  may  be  cut  with 
a  knife,  is  soluble  in  acids  with  efferves- 
cence, and  tfae  solution  appears  clear  and 
colourless.  Its  specific  gravity  is  8.919. 

By  Ruprecht's  analysis  100  parts  gave, 
sulphur  41.66,  oxide  of  lead  25,  oxide  of 
iron  16  66,  gold  11.66,  silver  2  33,  oxide  of 
arsenic  1,  oxide  of  antimony  2.08.  Some 
specimens,  however,  are  said  to  contain 
25  percent,  of  gold  combined  with  silver, 


ORE 

Klaprotli,  however,  found  in  it  but  little 
sulphur,  and  a  new  metal.  The  foliated 
sort  afforded  him  in  100  parts,  lead  50, 
tellurium  33,  gold  8.5,  sulphur  7.5,  silver 
and  copper  1.  The  yellow  gold  ore  of 
Xagyac  gave,  tellurium  45,  go  id  27,  lead 
19.5,  silver  8.5,  sulphur  an  atom.  From 
the  white  gold  ore,  or  aurum  graphicum, 
of  Otfenbanya,  in  Transylvania,  lie  obtain- 
ed tellurium  60,  gold  30,  silver  10:  and 
from  that  called  aurum  problematicum, 
or  paradoxum,  tellurium  92-55,  iron  7-2, 
gold  0.25. 

For  other  remarks  on  the  treatment  of 
gold,  and  its  ores,  see  the  article  Gold 
The  new  process  of  amalgamation,  invent- 
ed by  Baron  Born,  has  very  much  engaged 
the  attention  of  mineralogists;  for  which 
reason,  as  well  as  for  its  own  intrinsic  va- 
lue, we  shall  here  give  an  account  of  the 
process,  from  Raspe's  translation  of  the 
baron's  work  on  this  subject. 

The  amalgamation  of  gold  and  silver 
ores,  in  large  operations,  as  well  as  in 
smaller  assays,  requires  the  following  dis- 
tinct operations  i 

Stamping,  grinding,  and  sifting. 

Calcination,  and  repeated  grinding  and 
sifting. 

Trituration. 

Washing  of  the  residuum. 

Eliquation  of  the  amalgama. 

Heating  of  the  same. 

Distillation  of  the  quicksilver  pressed 
from  the  amalgama. 

Refining  of  the  heated  quicksilver ;  and 
lastly, 

Management,  use,  and  refining  of  such 
residua  as  still  appear  to  contain  some  of 
■he  nobler  metals. 

Stamping,  grinding,  and  sifting. 

By  these  operations  the  picked  ores, 
black  copper,  and  mixtures  of  metals  and 
semi-metals  are  reduced  into  fine  powder; 
and  their  surfaces  being  thus  increased, 
they  mix  and  calcine  better  with  the  com- 
mon or  rock  salt,  which  is  added  to  them; 
otherwise,  the  calcining  hie  and  the  air 
could  not  act  sufficiently  on  the  grosser 
particles,  nor  could  the  sulphuric  and  mu- 
riatic acids  properly  penetrate  them,  or  a 
perfect  desulphuration  and  decomposition 
of  such  substances  be  brought  on,  in 
which  the  gold  and  silver  particles  are 
disguised. 

These  operations  are  performed  at 
Glasshutte,  near  Schemnitz  in  Hungary, 
oi  dry  stamps  and  mills ;  but  at  Joachim- 
■sthal  in  Bohemia,  wet  stamps  have  been 
substituted,  by  which  means  the  loss  of 
dust  unavoidable  in  the  dry  grinding,  and 
also  the  injury  otherwise  done  to  the 
health  of  the  workmen,  are  prevented. 


ORE 

Calcination. 
Sulphur  can  be  expelled  from  ores  in 
open  fire  and  in  closed  vessels  but  imper* 
feclly,  unless  some  proper  substance  be 
added.  Thus,  for  example,  corrosive  sub- 
limate  is  used  in  order  to  separate  the  sul- 
phur from  some  ores ;  in  this  case  the  con- 
centrated muriatic  acid  unites  with  the 
metallic,  semi-metallic,  and  soluble  earthy 
particles,  passes  into  the  receiver  with  the 
arsenic  and  oxide  of  antimony,  and  the 
disengaged  quicksilver  sublimes  with  the 
disengaged  sulphur  in  the  form  of  cinna- 
bar. 

From  this  an  idea  may  be  formed  of 
the  calcination  of  those  ores,  which,  be- 
side particles  of  native  metal,  contain  dis- 
guised gold  and  silver,  which  would  ne- 
ver be  got  entirely  by  washing  or  other 
mechanical  contrivances,  without  some 
chemical  assistance.  This  is  their  calci- 
nation. By  fire  and  air  it  decomposes  the 
ores,  expels  the  sulphur,  puts  the  metal- 
lic and  semi-metallic  particles  into  the 
state  of  oxide,  and,  freeing  the  noble  me- 
tals from  their  disguises,  exhibits  them 
naked  in  their  metallic  form. 

If  there  be  sulphur  enough,  or  even  a 
superabundance  of  it,  calcination  will  pro- 
duce  this  desirable  effect  without  any 
other  addition  But  as  the  sulphuric  acid 
acts  on  the  ores,  and  disengages  the  gold 
and  silver  particles  only  in  proportion  as 
it  is  produced  from  the  sulphur  in  more 
or  less  quantity,  it  is  safer  to  depend  on 
the  muriatic  rather  than  the  sulphuric 
acid :  and  though  common  or  rock  salt, 
added  in  the  process  of  amalgamation  of 
well  calcined  ores,  answers  this  end  in 
some  respects,  yet  it  will  serve  better 
when  mixed  in  proper  proportions  with 
the  earthy  or  metallic  ores  before  they  go 
to  the  calcining  fire,  thus  undergoing  with 
them  a  similar  calcination.  The  quantity 
in  which  it  is  to  be  added  must  be  deter- 
mined by  experience. 

When  picked  and  haivan  ores  are  cal- 
cined with  common  salt,  the  sulphur  and 
arsenic,  if  any,  begin  first  to  be  disen- 
gaged. Fart  of  the  sulphur  flies  off  un- 
decomposed,  a  great  part  is  converted 
into  sulphuric  acid,  which  last,  uniting 
with  the  alkaline  and  metallic  earths  of 
the  base  metals  and  semi-metals,  but  in 
particular  with  the  mineral  alkali  of  the 
common  salt,  forms  with  the  first,  differ- 
ent earthy  and  metallic  (more  or  less  so- 
luble) neutral  salts,  and  with  the  last,  sul- 
phat  of  soda.  The  muriatic  acid  thus  dis- 
engaged begins  now  to  act  like  the  sul- 
phuric, and  is  absorbed  equally  by  the 
earths  and  the  metallic  oxides. 

The  muriatic  acid  consequently  pene- 
trates the  alkaline  and  metallic  earths 


ORE 


ORE 


more  completely  than  the  sulphuric  alone; 
for  if  there  be  salt  enough,  it  decomposes 
all  the  sulphuric,  earthy,  and  metallic  neu- 
tral salts,  by  its  different  elective  attrac- 
tions,  forming  therewith  various  new  deli- 
quescent and  very  soluble  earthy  and  me- 
tallic neutral  salts,  by  which  all  the  dis- 
guised gold  and  silver  particles  are  dis- 
engaged, laid  bare,  and  fitted  for  amalga- 
mation. 

When  auriferous  or  argentine  mixtures 
of  base  metals  and  semi-metals  undergo 
calcination,  fire  and  air  will  produce  it  in 
part,  but  slowly  and  imperfectly;  whereas 
with  common  salt,  or  properly  its  acid,  it 
succeeds  quicker  and  better.  There  is 
no  sulphur  here,  or  its  acid,  to  decompose 
the  salt  and  disengage  its  acid  ;  but  com- 
mon salt  decomposing  by  continued  heat, 
its  acid  separates  from  its  alkaline  basis, 
and  acts  immediately  as  a  solvent  of  the 
metallic  and  semi-metallic  particles.  The 
elective  attraction  of  these  metals  and  se- 
mi-metals seems  even  to  assist  the  de- 
composition and  power  of  the  salt. 

The  different  mixtures  of  these  alloys 
account  for  the  different  muriatic,  metal- 
lic, and  semi-metallic  neutral  salts.  For 
instance,  the  alloys  produced  by  the  fu- 
sion of  the  Hungarian  fallow,  or  gray  cop- 
per ores,  consist  of  antimony,  copper,  gold 
and  silver,  and  sometimes  also  of  some 
arsenic  and  iron,  which  in  the  alloys  from 
common  antimonial  gray  copper  ores  is 
but  in  a  very  inconsiderable  proportion. 
The  muriatic  acid,  disengaged  from  the 
salt,  unites  (gold  and  silver  excepted) 
with  the  other  metals  and  semi-metals, 
which  by  calcination  leave  the  gold  and 
silver  bare  and  undisguised. 

The  same  thing  happens  in  the  calcina- 
tion of  auriferous  or  only  argentine  black 
coppers.  By  the  addition  of  common  salt, 
the  copper,  iron,  arsenic,  and  sometimes 
the  antimonial  particles  are  not  only  ox- 
ided,  but  also  most  of  the  antimony  and 
arsenic  is  volatilized  and  destroyed. 

The  cobalt  alloys  produced  in  the  treat- 
ment of  arsenical  cobalt  and  silver  ores 
contain  very  often  a  great  quantity  of  bis- 
muth. The  calcination  with  common  salt 
acts  upon  them  in  a  similar  manner ;  but 
should  they  abound  in  bismuth,  which  is 
exceedingly  fusible,  this  semimetal  must 
be  taken  out  by  eliquation,  before  they  can 
be  well  calcined,  otherwise  the  bismuth 
would  run,  and,  if  not  wholly  prevent,  yet 
very  much  hinder  the  oxidation  of  the 
other  metallic  and  semimetallic  particles. 

In  calcining  mixtures  which  abound  in 
antimony,  and  particularly  in  arsenic,  it 
has  been  frequently  found,  that  more  or 
less  quantities  of  silver  and  copper  are 
carried  off  by  the  antimonial  and  arseni- 

YOL.  II. 


cal  muriat,  chiefly  when  the  calcining 

I  heat  has  been  too  sudden  and  brisk  for 
the  purpose  of  a  quick  oxidation  of  the 
antimony,  and  expeditious  expulsion  of 
the  arsenic ;  for  these  volatile  semimetals 
acquire,  by  the  muriatic  acid,  a  much 
greater  than  their  natural  power  to  carry 
off  and  volatilise  even  the  finest  metals. 

Whatever  these  mixtures  are,  or  may 
be,  they  must  have  gone  through  the 
stamps  and  mills,  and  have  been  com- 
pletely pulverized,  before  they  can  be 
committed  to  the  calcining  fire,  which  is 
a  flaming  fire  kept  up  by  the  worst  of 
fuel;  or  to  the  calcining  furnace,  which, 
consists  of  two  hearths,  which,  taken  to- 
gether, are  11  or  12  feet  by  5,  of  a  grate, 
smoke  and  dust  chambers, communicating 
with  a  flue,  and  sliding  dust-stoppers,  or 
dust-dampers. 

The  proportion  and  mixture  of  the  pick- 
ed and  halvan  or  stamp-stuff"  is  (in  Hun- 
gary) determined  by  and  depends  upon 
the  respective  produce  of  the  mines  and 
stamps,  which  is  commonly  two  in  three; 
and  with  regard  to  the  silver,  upon  their 
average  produce.  The  proportion  of  the 
salt  is  regulated  and  determined  by  the 
more  or  less  quantity  of  the  sulphur  of 
the  said  picked  and  halvan  ores. 

Thus,  for  example,  a  whole  work,  par- 
cel, or  stem  of  a  calcining  furnace  in  the 
quick-mills  in  Lower  Hungary,  consists  of 
30  cwt;  one  third  or  10  cwt.  of  which  are 
pulverised  picked  ore ;  and  two  thirds,  or 
20  cwt.  pulverised  stamp  or  halvan  ore. 
Sometimes  it  consists  of  two  fifths  of  the 
former  and  three  fifths  of  the  latter;  and 
in  that  proportion  it  contains,  upon  an 
average,  three  and  a  half j  three  and  three 
quarters,  or  four  ounces  of  silver  per  cwt* 
To  such  a  mixture  they  generally  add 
eight  per  cent,  of  rock  salt. 

The  calcination  of  mixtures  of  base  me- 
tals and  semimetals,  of  silvery  black  cop- 
pers, and  of  leadish  ores,  requires,  over 
and  above  the  salt,  an  addition  of  quick- 
lime, from  four  to  ten  or  twelve  per  cent. 
For  these  metallic  mixtures  otherwise 
rise  amazingly  in  the  calcining  heat,  and 
the  speiss  and  black  copper9  are  in  parti- 
cular apt  to  turn  clammy,  and  to  leave 
clots,  in  which  many  particles  remain  un- 
calcined;  but  both  these  inconveniences 
are  counteracted  by  the  lime.  It  prevents 
the  immediate  contact  of  the  metallic  par- 
ticles, and  their  running  in  the  calcining 
fire  :  moreover,  as  it  increases  the  surface 
of  the  whole  mixture,  the  single  parts  of 
the  same  are  more  effectually  acted  upon, 
oxided,  and  laid  bare  by  the  fire,  air,  and 
muriatic  acid. 

When  the  furnace  is  properly  heated, 
and  the  doors  of  the  dust-chambers,  an* 

b  b 


ORE 


ORE 


the  sliding-dampers,  or  dust-catchers  of 
the  flue,  arc  shut,  the  whole  parcel  of  ore 
(viz.  oOcwt.)  is  run  by  wheel-barrows  on 
the  flat  top  of  the  furnace  ;  when,  having 
been  equally  spread  into  an  even  surface, 
the  proper  proportion  of  salt  and  lime  is 
sifted  over  it.  and  the  whole  is  turned  and 
worked  with  iron  rakes  and  crooks,  in 
even,  direction,  until  the  whole  is  perfect- 
ly and  equally  mixed.  Thus  prepared,  it 
is  spread  into  a  square  surface,  and  mark- 
ed into  equal  divisions,  which,  in  due  suc- 
cession, are  let  down  (in  8  cvvt.  parcels) 
on  the  upper  hearth,  by  means  of  a  fun- 
nel, which  opens  upon  it  through  the 
lower  vault  or  floor  of  the  furnace.  On 
this  hearth  it  must  be  spread  and  extend- 
ed equally,  that  the  moisture  of  the  stamp 
or  halvan  ore  may  be  expelled,  before  it 
is  shoved  down  on  the  lower  hearth :  after 
which  the  upper  hearth  is  immediately 
filled  again  with  another  quantity,  that  ex- 
siccation and  calcination  may  be  perform- 
ed at  the  same  time,  by  the  same  tire. 

In  the  calcination,  the  following-  pheno- 
mena take  place:  on  the  surface  of  the 
picked  and  halvan  ores,  when  brought  on 
the  lower  hearth,  and  stirred,  an  undu- 


acid  smell  disappears,  when  the  ore  that 
had  been  rising  begins  to  sink,  and  the 
clotting  ceases,  for  then  part  of  the  mu- 
riatic arid  flies  off.  On  taking  a  ladle  full 
of  it  for  proof,  or  even  on  smelling  the 
whitish  rarefied  smoke  near  the  back  door 
of  the  furnace,  the  smell  of  pure  muriatic 
acid  is  perceived- 

Most  ores  and  mixtures  of  ores,  chiefly 
when  containing  a  great  proportion  of  py- 
rites, or  when  there  happens  to  be  a  sul- 
phuretted copper  ore,  show  at  this  period 
a  luminous  phosphoric  appearance,  when 
suddenly  taken  from  the  hearth,  and  im- 
mediately examined  in  the  dark-  In  a  mo- 
derate heat  and  cold  weather,  they  like- 
wise show,  during  the  stirring,  bright  lu- 
minous sparks,  flying  and  scattering  about 
like  fire-works. 

When  the  sulphur  is  sufficiently  expell- 
ed, and  part  of  the  muriatic  acid  is  gone  ; 
when  the  whole  begins  to  subside,  and 
the  clotting  to  be  less ;  and  when  all  the 
above-mentioned  phenomena  have  appear- 
ed, then  the  calcination  is  deemed  to  be 
perfect. 

The  colour  of  the  calcined  ores  and 
halvans  is  generally  red,  r«  ddish  gray, 


lating  motion  is  observed,  and  a  volatile  j  dark  red,  or  red-brown,  according  to  the 
sulphureous  acid  smell  is  perceived ;  after 
which  the  sulphur  begins  to  disengage  it- 
self, burning,  covering  the  whole  (when  j  They  are  of  a  lighter  ana  1  igh 
the  ores  are  very  sulphureous)  with  a  blue  >  very  earthy ;  brown  when  ver 
flame,  and  flying  off  at  last  in  the  form  of j  or  mixed  with  manganese ;  and  yellowish 


proportion  of  the  eaVthy  and  me  ail  l  ie  par- 
ticles, or  of  the  sulphur  they  contained. 

red  when 
coppery, 


a  whitish  thick  suffocating  smoke 

Whilst  the  sulphur  is  thus  disengaged 
and  decomposed  in  a  low  or  gentle  Are, 


red  when  lead  prevails  in  their  mixture. 

Copper  mixtures,  containing  a  much 
greater  proportion  of  sulphur,  must  un  - 


the  sulphuric  acid,  thence  produced,  de-  ;  dergo  a  longer  calcining  heuL  than  other 
composes  the  common  salt,  combines  with  i  mixtures  of  ores  and  halvans.  W  hen  mix- 
its  soda,  and  disengages  the  muriatic  acid,  ,  ed  with  lead,  or  antimony,  and  arsenic, 
which  presently  unites  with  the  alkaline  I  they  must  be  put  to  calcine  not  oal]  with 
and  metallic  earths.    At  this  time  the  ore  !  common  salt,  but  also  with  a  proportion- 


begins  to  clot,  to  rise,  extend,  and  increase 
in  bulk  and  surface  It  begins  to  look  like 
wet  ashes,  and  to  diff  use  a  mixed,  sulphu- 
reous, saline,  acid  smell,  which  proceeds 
from  a  lighter  whitish  or  grayish  blue 
smoke  flying  off  from  the  surface. 

From  this  instant  the  fire  and  furnace 
may  be  kept  a  little  brighter,  yet  the  ore 
must  be  continually  stirred  and  turned 
over  from  one  side  of  the  furnace  to  the 
other ;  otherwise  it  would  be  calcined  un- 
equally, and  some  particles  would  remain 
undecomposed.  If  the  furnace  and  fire 
were  kept  too  bright,  the  sulphur,  arse- 
nic, and  saline  acid  particles,  too  briskly 
expelled,  would  unavoidably  carry  along 
with  them,  and  volatilize,  many  other,  nay 
even  metallic  particles. 

When  the  sulphuv  begins  to  disengage, 
the  ore  changes  its  colour;  it  changes 
again  when  the  calcination  is  over  at  its 
rising  and  subsidence,.   The  sulphureous 


ate  quantity  of  quick-lime,  that  the  ex- 
cess of  muriatic  acid  may  be  taken  from 
the  muriats  of  antimony  and  arsenic,  and 
from  the  plumbum  corneum,  which  are 
produced  during  the  calcination,  and  be 
absorbed  by  the  lime,  whieb  prevents  the 
untoward  clotting  of  the  particles. 

The  same  cautions  must  be  observed 
in  the  calcination  of  the  mixtures  of  base 
metals  and  semimetals,  and  of  the  silvery 
black  coppers,  for  they  also  contain  a 
considerable  proportion  of  antimony  and 
arsenic.  If  not  calcined  with  lime,  along 
with  the  common  salt,  they  pack  at  the 
very  instant  the  antimony  and  arsenic  are 
oxided  and  volatilized  in  the  form  of  a 
white  very  thick  smoke,  which  is  brought 
about  very  expeditiously  by  the  disen- 
gaged muriatic  acid. 

The  mixtures  of  metals  and  semimetals 
and  the  black  coppers,  containing  little  or 
no  sulphur,  the  common  salt  calcined  with 


ORE 


ORE 


them  is  decomposed  by  the  action  of  the 
fire  The  muriatic  acid,  thus  set  free, 
promotes  their  oxidation,  and  forms  with 
their  oxides  different  perfect  or  imperfect 
neutral  sails,  disengages  the  disguised 
gold  and  silver  particles,  while  the  soda 
remains  free  and  in  a  caustic  state :  for, 
in  the  dry  way,  the  muriatic  acid  leaves 
its  alkali,  and  combines  with  the  metals 
and  their  oxides  ;  but,  by  subsequent  so- 
lution in  water,  it  returns  to  the  alkali, 
forming  ag;-.in  with  it  common  salt,  and 
consequently  lets  go  the  metals,  semime- 
tals,  and  earthy  particles,  before  in  solu- 
tion. 

In  the  calcination  of  these  metallic  mix- 
tures and  the  black  coppers,  the  before- 
mentioned  luminous  phosphoric  appear- 
ance does  not  take  place;  but  the  flame 
which  passes  over  them  affects  various 
colours,  and  in  particular  the  red  and 
blue,  both  owing  to  volatilized  particles 
of  copper. 

When  antimonial  stone,  black  copper, 
and  mixtures  of  metals  and  semimetals, 
are  put  to  calcine,  the  antimony  oxides 
tirst,  forming  a  white  oxide  in  the  flues 
and  other  passages ;  arsenical  mixtures 
diffuse  a  white  smoke  and  garlic  smell ; 
those  which  abound  in  lead  and  zinc 
(which  last  require  a  stronger  and  longer 
lire)  produce  saturnine  zincous  smoke, 
and  white  flowers. 

When  the  calcination  of  these  metallic 
mixtures  is  perfected,  and  the  remainder 
is  cooled,  their  oxides  appear  brownish 
gray,  or  dark  gray ;  and  those  of  the  stone 
and  copper  mixtures  of  a  more  or  less  sa- 
turated red  colour,  except  those  which 
abound  in  lead. 

The  surest  symptoms,  however,  of  their 
perfect  calcination,  are,  collectively,  the 
rising  and  sinking  of  the  mixtures,  their 
colour,  and  the  acrid  smell  of  the  muria- 
tic acid.  Then  only  the  gold  and  silver 
particles  may  be  deemed  to  be  fully  dis- 
engaged. 

Sifting  and  grinding  after  calcination. 

The  grinding  and  sifting  of  the  stuff  is 
as  necessary  after  as  before  calcination, 
because  the  stamp  and  halvan  stuff",  which 
is  mixed  up  with  the  picked  ore,  could 
not  be  sifted  or  ground  previous  to  its  cal- 
cination, on  account  of  its  moisture.  This 
further  grinding  and  sifting  serves  like- 
wise fully  to  pulverize  and  equalize  the 
elots  of  the  mixtures  of  metals  and  semi- 
metals. 

If  these  coarser  particles  Were  suffered 
to  remain  as  they  are,  they  might  still  dis- 
guise many  gold  and  silver  particles,  and 
guard  them  against  amalgamation. 

This  repeated  grinding  and  silting  may 


be  dispensed  with  when  the  whole  stuff 
is  of  an  equal  size,  and  sufficiently  hue ; 
but  its  clots  will  at  any  rate  require  exa- 
mination, whether  they  be  soluble  in  wa- 
ter or  not,  for  those  of  leady  and  me  tallic 
mixtures  remain  insoluble,  if  soluble,  and 
not  leaving  sharp  coarse  particles  between 
the  fingers,  they  want  neither  grinding  nor 
sifting,  but  they  must  go  through  both 
these  operations  when  insoluble,  and  when 
they  betray  such  coarse  particles  on  being 
rubbed  between  the  fingers. 

Trituration,  boiling,  and  amalgamation  of 
the  calcined  stuff. 

By  amalgamation  we  understand  that 
mechanical  and  chemical  operation,  in 
which,  by  means  of  quicksilver,  heat,  un- 
interrupted motion,  and  successive  con- 
tact of  the  particles,  gold  and  silver  (pre- 
viously disengaged  from  their  disguises, 
by  calcination  and  pulverization,)  are  ex- 
tracted from  their  earthy,  metallic,  or  mi- 
neralized matrices,  and  combined  with 
quicksilver. 

If  the  ores  have  been  duly  pulverised, 
and  calcined,  the  success  of  trituration  or 
amalgamation  mostly  depends  on  the  pro- 
per proportions  of  the  quicksilver  and  wa- 
ter which  are  added  to  the  stuff":  it  like* 
wise  depends  on  the  goodness  and  con- 
struction of  the  stirring  apparatus,  by 
which  the  whole  mixture  is  kept  in  con- 
stant motion  and  mutual  contact  Even 
the  degree  of  heat,  and  the  quickness  of 
the  trituration  or  stirring,  contribute  to 
the  quicker  and  perfect  amalgamation. 

To  determine  the  quantity  of  quicksil- 
ver, the  weight  and  bulk  of  the  calcined 
stuff  are  to  be  considered.  The  lighter, 
the  stuff,  the  more  voluminous  it  will 
prove,  and  consequently  the  gold  and  sil- 
ver will  be  the  more  dispersed.  In  this 
case  the  quantity  of  quicksilver  must  be 
proportioned  to  the  mass.  Thus,  for  ex- 
ample, 2  cwt.  of  picked  ore  and  halvans 
are  more  bulky  than  2  cwt.  of  calcined 
copper  or  other  mixtures.  The  former, 
therefore,  require  a  larger  quantity  of 
quicksilver. 

Both  in  small  and  great  operations,  ex- 
perience has  determined,  that  an  excess 
of  quicksilver  is  never  hurtful,  and  that, 
on  the  contrary,  a  scanty  proportion  is  at- 
tended with  loss.  It  may  be  taken  in  the 
proportion  of  one  to  two,  that  is  1  cwt.  of 
quicksilver,  to  2  cwt  of  stuff.  In  this  pro- 
portion, it  does  not  increase  the  cost  of 
washing  and  pressing,  nor  is  any  loss  of 
quicksilver  incurred ;  the  full  produce  of 
noble  metal  is  thus  secured,  and  the  re* 
siduum  is  left  poorer. 

The  vessels  or  boilers,  in  which  the 
quicksilver  and  stuff  are  triturated,  arc 


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of  copper,  of  an  inverted  conical  form, 
and  with  a  concave  bottom.  No  boiling- 
heat  required :  a  heat  of  50°  or  60°  is 
sufficient. 

Is'o  more  water  is  required,  than  will 
soak  inio,  and  make  the  stuff  liquid.  Ex- 
cess of  water,  makes  the  quicksilver  sink 
too  fast,  and  keeps  the  lighter  and  finer 
particles  of  the  metals  floating  on  the  sur- 
face ;  which  of  course  prevents  the  per- 
fect success  of  the  operation.  On  the 
other  hand,  too  little  water  leaves  the  stuff 
too  thick,  which  makes  the  stirring-  very 
troublesome  ;  moreover,  the  evaporation 
of  the  water,  soon  forms  a  dry  and  hard 
Crust,  on  the  sides  of  the  boiler,  which  is 
attended  with  loss  of  silver  in  the  resi- 
duum. Experience  must  determine  the 
proper  respective  measure  of  water. 

The  stirring-  apparatus  is  put  into  mo- 
tion by  means  of  a  water-wheel. 

The  stirrers  or  stirring-racks  (which 
were  at  first  made  of  copper,  but  have 
since  been  found  to  answer  better  when 
made  of  wood)  are  circular  segments,  cor- 
responding- with  the  sides  and  bottom  of 
the  boiler. 

Experience  only  can  determine  how  long 
the  respective  stuffs  must  be  triturated 
with  quicksilver.  It  has  been  found,  that 
some  stuff  yields  its  gold  and  silver  to  the 
quicksilver, perfectly  and  completely  with- 
in eight  or  ten  hours  ;  other  mixtures  re- 
quire a  trituration  of  12  or  15  hours.  Ex- 
cess of  time  or  longer  trituration,  is  never 
hurtful ;  too  little  of  it  will  often  lessen 
the  produce. 

Washing  of  the  triturated  leavings,  or  resi- 
duum. 

The  object  of  the  trituration  already  de- 
scribed was  to  unite  the  gold  and  silver 
particles  of  the  calcined  stuff',  into  an 
amalgama  with  quicksilver  :  the  object 
of  this  washing,  is  the  separation  of  this 
rich  amalgama,  from  the  leavings  or  resi- 
duum. 

This  washing  is  performed  in  a  large 
tub,  of  a  conical  form,  with  a  rake  within 
it,  contrived  so  as  to  be  thrown  into  a  ro- 
tatory motion,  by  a  water-wheel,  or  by- 
hand  ;  with  side  cocks  for  drawing  off 
the  water ;  and  with  a  bottom  cock  for 
tapping  off  the  amalgama  or  quicksil- 
ver. 

The  particles  of  quicksilver  and  amal- 
gama, kept  floating  in  the  whole  liquid 
mass,  by  the  continual  rotation  of  the  rake, 
sink  by  their  gravity,  and  collect  in  the 
concave  bottom  of  the  tub,  above  the  cock; 
but  the  remaining  stuff  or  ore,  and  stony 
matter,  being  much  lighter,  is  kept  float- 
ing. When  the  whole  has  been  suffici- 
ently stirred  about  in  this  manner,  with 


the  water,  the  bottom  cock  of  the  washing 
tub  is  opened,  and  the  quicksilver  and 
amalgama  are  thereby  let  out ;  after  which 
one  (or  more)  of  the  side  cocks  (which 
are  fixed  at  different  heights)  is  opened 
to  let  out  the  thin  liquid  stuff. 

Eliquation  of  the  quicksilver  and  amal- 
gama. 

The  quicksilver,  triturated  with  rich 
stuffs, is  strained  through  a  kind  of  hitrum, 
for  the  purpose  of  bringing  tlie  gold  and 
silver  particles  into  a  smaller  compass,  and 
of  separating  them  from  the  excess  of 
quicksilver;  although  the  whole  can  ne- 
ver be  separated  but  by  fire. 

This  is  done  by  means  of  a  box,  on  the 
circular  opening  of  which  lies  an  iron 
ring,  to  which  is  fixed  a  bag  of  linen  da- 
mask. The  quicksilver  (its  surface  hav- 
ing been  previously  cleansed  with  a  sponge 
from  any  muddy  water,  or  stuff  that  might 
adhere  to  it)  is  poured  in  small  quantities 
into  this  bag  by  one  person,  whilst  another 
presses  it  with  his  hands,  until  the  ball  of 
amalgama,  collecting  and  forming  apace, 
no  longer  yields  any  quicksilver.  \Y  hen  the 
ball  becomes  too  big  for  pressure,  with 
two  hands,  it  is  taken  out,  and  another  is 
formed  in  the  same  manner,  until  all  the 
quicksilver  has  gone  through  the  bag  The 
balls  of  amalgama  are  put  into  a  wooden 
box 

The  quicksilver  which  has  been  strained 
through  the  bag  (and  which  always  con- 
tains from  twenty  to  thirty  penny-weights 
of  gold  and  silver  per  cwt)  is  collected 
in  a  reservoir  under  the  b  x,  and  serves 
again  for  trituration,  with  fresh  quantities 
of  ore. 

Heating  and  sublimation  or  distillation  of 
the  amalgama. 
The  amalgama  balls,  obtained  by  press- 
ing or  eliquating  the  quicksilver,  consist 
(according  to  the  different  degrees  of 
pressure,  they  underwent)  of  one  part  sil- 
ver, and  fbur,five,  or  six  parts  quicksilver. 
This  is  expelled  from  them  by  fire  in  close 
vessels.  It  is  a  distillation  per  descensum, 
performed  in  large  cast-iron  pots,  put 
over  each  other.  The  fire  is  kept  up  for 
five  or  six  hours.  The  heat  acting  through 
the  pots  on  the  amalgama,  volatilizes  the 
quicksilver,  which  rising  in  the  form  of 
vapour,  and  finding  no  passage  in  the  in- 
verted upper  pot,  is  forced  down  into  the 
lower  one,  and  collects  there  by  the  way 
of  distillation,  being  condensed  and  pre- 
cipitated by  the  coolness,  that  is  con- 
stantly kept  up,  by  cold  water  applied 
to  the  outside  of  the  lower  pot  or  re- 
ceiver. 

When  no  copper  has  been  revived,  and 


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the  amalgama  lias  been  perfectly  treated,  | 
all  the  quicksilver  is  recovered  without 
loss,  and  the  balls  are  white  like  silver,  j 
and  mossy  on  their  surfaces.    If  coppery,  j 
they  have  a  reddish  cast ;  and  are  brown- 
ish, if  the  copper  had  undergone  a  su- 
perficial oxidation.    If  leady,  which  is  sel- 
dom the  case,  they  show  a  dark  pearl- 
giay  colour. 

Refining  and  cupcllution  of  the  sliver. 

The  amalgama,  according-  to  their 
coppery  or  leady  appearance,  or  to  their 
purity,  are  either  refined  by  cupellaUon, 
or  simply  melted  down,  and  run  into  in- 
gots. 

W  hen  containing  no  gold,  they  may  be 
delivered  to  the  mint,  without  further  fu- 
sion or  cupellation,  notwithstanding  their 
copper  alloy ;  but  if  auriferous  and  cop- 
pery, then  they  must  be  refined,  or  put 
to  cupellation,  that  the  copper  may  be 
destroyed,  and  the  auriferous  silver  be 
brought  to  the  standard  of  15  iotb,  15 
grains  per  marct  in  which  it  is  received  at 
the  mint. 

Distillation  of  the  quicksilver,  separated 
from  the  amalgam  by  heat  or  pressure. 
The  quicksilver,  separated  by  heat  from 
the  amaigam,  contains  some  of  the  noble 
metals,  which  passed  with  it  through  the 
pressing-bag.  This  generally  amounts  to 
three  quarters  of  an  ounce,  or  one  ounce 
per  cwt.  But  this  quicksilver  being  con- 
stantly on  hand,  and  always  serving  in  the 
subsequent  triturations,  its  contents  of 
gold  and  silver,  need  only  to  be  ascertain- 
ed once  at  the  annual  balance  of  the  ac- 
counts. This  may  be  done,  in  small  assays, 
by  distilling  the  quicksilver,  with  granu- 
lated lead,  in  glass  retorts  ;  but  the  ope- 
ration succeeds  best,  in  tubulated  iron  re- 
torts, with  cast-iron  receivers,  filled  with 
water,  and  luted  to  the  necks  of  the  re- 
torts. Each  of  these  is  sunk  half  into  the 
furnace,  with  its  neck  much  inclined  into 
the  receivers.  They  are  filled  with  two 
cwt.  of  quicksilver,  to  which  is  added, 
half  a  pound  or  a  pound  of  granulated 
lead.  The  tubulated  opening  of  the  re- 
tort, and  the  neck  of  the  receiver,  must 
be  carefully  luted  with  refractory  clay. 
The  fire  should  be  brisk,  and  the  whole 
body  of  the  retort  be  covered  with  the 
burning  fuel.  The  quicksilver  rises  up  in 
the  form  of  vapour,  and  passes  over  into 
the  receiver,  where  it  is  condensed,  col- 
lected into  drops,  and  falls  to  the  bottom 
of  the  water.  All  the  auriferous  silver 
remains  behind,  united  with  the  lead, 
which,  if  it  siiouid  stick  to  the  bottom  of 
the  retort,  may  be  melted  in  it  by  a  coal- 
iire,  and  poured  out  into  an  ingot,  to 


be  afterwards  put  to  t'.>e  test  or  cupel- 
lation. 

Further  treatment  and  use  of  the  triturated 
testdua,  which  have  gone  through  the  pro- 
cess of  amalgamation. 
The  residua  commonly  contain  some 
gold  and  silver,  more  or  less,  according- 
as  they  were  well  or  badly  pulverized, 
oxided',  sifted,  triturated  and  washed.  If 
the  residuum  should  contain  more  than 
one  ounce  per  cwt.,  and  raw  unoxided 
particles  appear  in  the  same,  it  will  be 
advisable  to  oxide  it  once  more,  with  an 
addition  of  four  per  cent,  of  sait,  and  to  let 
it  undergo  a  second  amalgamation.  If  k 
should  be  of  an  equal  size,  and  perfectly 
oxided,  it  should  be  mixed  up  with  ne\V 
stuff,  or  triturated  once  more  alone. 

If,  on  the  contra,  v,  the  residuum  is  sil- 
very, in  consequence  of  the  imperfect 
washing  and  separation  of  the  quicksilver 
and  amalgam,  it  must  be  washed  over 
again,  more  abundantly  diluted  with  wa- 
ter. 

The  lixivia  containing  copper,  are  preci- 
pitated by  iron. 

The  Editors  of  the  Chemical  Journal 
add  the  following  remarks,  in  a  note,  on 
the  cold  amalgamation  : 

Considering  the  complex  apparatus  for 
the  warm  amalgamation,  the  wear  and 
loss  of  the  copper  boilers,  the  unequal' 
produce,  and  the  expense  of  firing,  (all 
which  are  now  avoided)  the  cold  amalga- 
mation is,  as  Mr.  Raspe  observes,  a  noble 
improvement  of  the  process.  It  is  what 
baron  Born  always  aimed  at,  though  his 
attempts  were  unsuccessful.  Mr.  Gellert, 
at  Freyberg,  first  succeeded  in  it,  using 
wooden  cylindrical  churns,  with  perpen- 
dicular pistons,  laid  over  with  copper 
sheeting,  which,  by  a  quick  motion  up 
and  down,  produce  a  stronger  trituration 
than  the  rotatory  horizontal  motion  of1 
barrels,  and  at  the  same  time,  prevents 
the  possibility  of  producing  sublimate,  or 
mercurius  dulcis,  by  the  excess  of  muri- 
atic acid,  acting  upon  the  quicksilver,  te 
which  that  acid  has  less  affinity  than  to 
copper. 

His  first  experiment,  was  attended  with 
uncommon  success;  for,  by  cold  churn- 
ing, he  extracted  the  silver  from  pulve- 
rised ore,  which  contains  but  three  ounces 
and  a  quarter  per  quintal,  in  the  course  of 
sixteen  hours,  so  completely,  that  the 
leavings  contained  but  two  clwts.  (The 
operation  niay  even  be  finished  in  ten 
hours,  whilst  others  requu-ed  twenty- 
four.)  Upon  these  principles,  the  churn- 
ing apparatus,  in  wooden  cylinders,  has 
been  adopted  in  Bohemia,  with  a  perfo- 
rated cast-iron  piston,  which,  by  a  crank 


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motion,  moves  quickly  up  and  down. 
Though  the  whole  is  put  in  cold,  yet,  at 
the  end  of  the  operation,  it  heats,  in  con- 
sequence of  the  quick  trituration  and  mo- 
tion of  the  pistons. 

At  Freyberg,  this  cold  amalgamation  is 
performed  in  a  mill,  which  turns  eight 
large  barrels,  each  holding  ten  and  an  half 
quintals  of  ore.  The  ores  are  dressed  to 
contain  four  ounces  per  quintal,  mixed 
with  10  per  cent,  of  salt,  and  calcined  and 
sifted  in  baron  Born's  manner.  When  put 
into  the  barrels,  one-fourth  per  cent,  of 
quicklime,  and  34  lbs  of  water  are  added, 
and  turned  briskly  two  hours,  thirty-six 
turns  per  minute.  The  lime  absorbs  the 
excess  of  acids.  To  counteract  the  de- 
composition of  metallic  sulphats,  and  the 
precipitation  of  silver  particles,  (which  an 
excess  of  lime  might  occasion)  after  two 
hours  turning,  two  per  cent,  of  thin  rolled 
iron  chips,  two  inches  square,  are  thrown 
into  the  barrels,  and  turned  with  the  same 
two  hours.  Then  the  quicksilver,  half  a 
quintal  to  one  quintal  of  ore,  is  added, 
together  with  an  additional  four  per  cent, 
of  iron  chips,  previously  coated  with  a 
little  copper,  by  immersion  in  copper  wa- 
ter, in  order  to  prevent  the  dispersion  of 
the  quicksilver,  and  to  catch  and  attract 
its  smallest  particles.  After  the  last  cop- 
pery-iron chips,  and  the  quicksilver  have 
been  added,  the  barrels  are  turned  slower, 
at  the  rate  of  twenty  or  twenty-five  turns 
per  minute.  After  twelve  hours  turning, 
all  the  silver  is  extracted,  except  one  and 
a  quarter  dwt.  per  quintal,  which  can- 
.  not  be  farther  extracted  by  amalgama- 
tion. 

Ores  of  Iridum. 
This  metal  has  been  found  hitherto  only 
in  the  black  powder  left,  after  dissolving 
platina. 

Ores  of  Iron. 

When  we  consider  the  great  destructi- 
lfosiity  of  iron,  by  the  disengaged  acids,  and 
other  uncombined  agents  in  nature,  it  is 
not  to  be  expected,  that  much  native  iron 
should  be  found.  We  have,  however,  in- 
dubital  accounts  of  its  existence  in  various 
parts  of  the  world.  The  most  remarka- 
ble mass  of  this  sort,  was  discovered  in 
Siberia,  by  professor  Pallas,  which  weigh- 
ed 1600  pounds.  Specimens  of  this  have 
been  sent  to  all  parts  of  Europe.  It  is  of 
that  species  called  red  short,  being  mal- 
leable while  cold,  but  brittle  when  red- 
hot  This  has  lately  been  classed  with 
the  stones  called  meteoric.  See  the  con- 
clusion of  the  article  Meteorology 

Bergman  considers  mispickle,  as  a  mix- 
ture at  native  iron  and  ajrsenic.  It  is  call* 


ed  Pierre  de  Sante  by  the  French,  but  for 
,!1  at  reason  I  know  not,  and  is  cut  for 
toys.  Thirty  or  forty  years  ago,  a  mine- 
ral was  in  common  use,  for  this  purpose 
in  England.  The  small  stone  or  pieces 
were  called  marcasites,  and  were,  I  sup- 
pose, mispickel. 

The  magnet,  or  loadstone,  is  an  ore  con- 
taining  iron,  approaching  to  the  metallic 
state.  It  has  not  been  much  examined, 
probably  on  account  of  the  heterogeneous 
nature  of  the  various  stones  called  by  this 
name.  Magnetism  is  their  characteristic 
property,  but  they  may  nevertheless  dif- 
fer exceedingly  in  their  contents,  so  as 
scarcely  to  come  under  the  same  minera- 
logical  arrangement.  Some  contain  as 
much  as  75  per  cent,  of  iron.  See  Mag- 
netism. 

The  black  iron  ore,  or  steel  ore,  is  pon- 
derous, of  a  very  dark  gray  colour,  or  ra- 
ther slate  black,  and  affords  a  black  pow- 
der when  scraped.  Some  specimens,  how- 
ever, afford  a  red  powder.  It  is  readily 
attracted  by  the  magnet.  Its  fracture  ex- 
hibits grains  more  or  less  fine,  or  else 
scales  or  facets,  whence  it  has  been  im- 
properly called  galena  of  iron.  When  ex- 
posed to  heat,  it  gives  scarcely  any  smell, 
and  changes  its  colour  very  little,  though 
its  shining  appearance  goes  off.  A  strong 
heat  renders  it  partly  malleable.  It  gives 
fire  with  steel,  in  consequence  of  a  pro- 
portion of  quartz  it  contains.  Acids  act 
upon  it  to  a  certain  degree,  but  the  iron  is 
too  much  oxided  to  afford  many  crystals 
with  the  sulphuric  acid. 

That  species  of  black  iron  ore,  which 
has  the  form  of  octahedrons,  nearly  re- 
sembles the  foregoing  in  its  properties. 

The  ochres  are  very  common,  and  ap- 
pear to  have  been  produced,  by  the  de- 
composition of  pyrites;  see  Ochres. 
There  are  two  varieties  ;  1.  Yellow  ochre  : 
this  becomes  red  by  calcination.  2.  Red 
ochre.  Both  these  are  so  common,  and  so 
much  used  in  the  arts,  that  it  is  scarcely 
requisite  to  describe  the  great  variations 
of  colour  and  consistence,  the  several  spe- 
cimens possess. 

Earthy,  argillaceous,  or  bog  ores  of  iron, 
are  of  different  colours,  reddish,  yellow- 
ish, brown,  and  sometimes  gray,  especi- 
ally after  exposure,  to  the  air  for  a  time. 
Internally  they  have  a  blueish  gray,  or  iron 
colour  This  ore  is  brittle,  and  resembles 
scoriae,  or  small  rounded  or  flattened 
stones,  not  obedient  to  the  magnet,  and  in 
general  of  inconsiderable  hardness  It 
mostly  abounds  with  foreign  sandy,  argil- 
laceous, or  calcareous  matters. 

The  crystallized  iron  ore  of  the  island 
of  Elba  is  one  of  the  most  beautiful  of 
minerals.   It  has  not  vet  been  found  «s- 


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cept  in  that  island.  It  is  found  in  differ- 
ent states,  in  ochres  of  every  shade,  in 
the  argillaceous  sandy  ore,  in  crystallized 
ore,  and  in  hematites.  The  crystallized 
is  the  most  common,  the  purest,  and  most 
beautiful.  Its  form,  as  well  as  colour, 
varies  much.  The  shades  are  green,  red, 
black,  yellow,  brown,  blue,  and  violet ; 
and  some  exhibit  all  the  various  and  live- 
ly colours  of  precious  stones,  though  this 
brilliant  appearance  becomes  tarnished  by 
the  moisture  of  the  air.  This  ore  is  very 
ponderous  and  hard,  and  frequently  mix- 
ed with  copper  pyrites.  Acids  do  not  at- 
tack it,  neither  is  it  affected  by  the  mag- 
net, at  least  while  in  the  mass  :  we  do  not 
find  that  this  ore  has  been  well  analysed. 
Some  writers  pretend,  that  sulphur  is  the 
mineralizer,  and  others,  carbonic  acid  ; 
but  from  its  great  resemblance  to  the 
combination  of  iron  with  water  in  the  ex- 
periment of  the  gun-barrel,  it  appears 
likely  that  that  fluid,  as  one  of  its  princi- 
ples, enters  into  the  iron  ore  of  the  isle  of 
Elba. 

Hematites  exists  in  considerable  abun- 
dance in  the  iron  mines  of  ancient  forma- 
tion. It  is  formed  in  the  manner  of  sta- 
lactites and  stony  concretions.  In  gene- 
ral it  possesses  considerable  hardness,  so 
as  sometimes  to  give  fire  with  steel.  The 
varieties  are, 

1.  Blackish  hematites ;  fracture,  vitre- 
ous, and  sometimes  shining ;  texture,  fi- 
brous or  striated ;  colour,  brown  black, 
but  reddish  when  pounded.  It  gives  fire 
with  steel,  becomes  darker  coloured,  and 
as  it  were  scaly,  by  ignition. 

2.  Red  hematites.  This  is  chiefly  enti- 
tled to  the  name  of  blood-stone,  from  its 
colour.  It  is  very  heavy,  ponderous,  stri- 
ated, and  as  if  crystallized,  or  in  small 
globules,  called  kidney-ore. 

3.  Yellow  hematites.  This  differs  from 
the  preceding,  from  the  degree  of  the  ox- 
idation of  its  metallic  part,  in  the  same 
manner  as  yellow  ochre  differs  from  red. 

The  specular  iron  ore,  mentioned  by 
Mongez  among  the  oxides  of  iron,  is  easi- 
ly distinguished  by  its  brilliant  facets, 
which  often  resemble  polished  steel.  It 
is  distinguished  from  the  iron  ore  of  Elba 
by  a  small  portion  of  sulphur,  which  it 
contains.  It  is  plentifully  found  at  Mount 
d'Or  in  Auvergne. 

Emery  was  considered  as  an  ore  of 
iron,  which  has  the  appearance  of  a  very 
compact  granular  stone,  of  a  black.-ih, 
grayish,  or  brown  colour.  By  calcination 
it  becomes  brown  or  red,  and,  as  Mongez 
says,  harder  than  before.  It  is  used  as  a 
grinding  and  polishing  powder,  and  is 
scarcely  inferior  in  hardness  to  any  sub- 


stance but  the  diamond.  Its  specific  gra-* 
vity  is  from  3.008  to  4.000.  The  best  sort 
is  of  a  dark  gray  colour.  It  is  never 
wrought  as  an  iron  ore.  Late  experi- 
ments appear  to  have  classed  it  with  Co- 
rundum. 

The  white  or  sparry  iron  ore,  or  stahk 
stein  of  the  Germans,  consists,  according 
to  Bergman,  of  the  brown  oxide  of  iron 
united  with  the  white  oxide  of  manga- 
nese, and  carbonat  of  lime,  in  various 
proportions.  Bayen  examined  a  speci- 
men from  Germany  of  the  best  steel  ore, 
and  found  it  to  contain  two  thirds  iron, 
and  the  rest  carbonic  acid,  except  a  small 
portion  of  zinc.  The  figure  of  this  ore  is 
either  irregular  or  rhomboidal;  frequent- 
ly transparent ;  its  texture  seal)',  lamel- 
lar, granular,  or  cellular.  Sometimes  it 
possesses  a  stalactitical  form,  and  is  some- 
times found  in  a  blackish  brown  powder- 
Its  colour,  when  fresh  dug,  is  whitish,  but 
by  exposure  to  the  air  it  becomes  gray, 
brown,  reddish,  yellowish,  or  black.  Its 
specific  gravity  is  from  3.6  to  4  0.  It  does 
not  give  fire  with  steel,  unless  by  virtue 
of  particles  of  quartz  or  pyrites,  with 
which  it  is  frequently  interspersed  In 
the  fire  it  decrepitates,  grows  black,  be* 
comes  magnetic,  and  loses  about  one  third 
of  its  weight  by  the  extrication  of  carbo- 
nic acid  '  One  hundred  parts  of  this  ore 
from  Eisenartzin  Stiria,  afforded  Bergman 
38  of  the  brown  oxide  of  iron,  24  of  the 
white  oxide  of  manganese,  and  38  of  car- 
bonat of  lime.  The  iron  answering  to  this 
quantity  of  oxide  is  about  32  parts,  qr 
one  third  of  the  whole. 

Iron  mineralized  by  sulphur  is  mostly 
distinguished  by  the  name  of  pyrites.  It 
seldom  contains  iron  in  sufficient  quanti- 
ty to  be  extracted  with  profit,  not  only 
because  a  long  continued  heat  is  required 
to  drive  off"  the  last  portions  of  sulphur, 
but  likewise  because  the   iron  usually 
proves  of  a  bad  quality.  This  ore  has  va- 
rious degrees  of  hardness  and  consisten- 
cy ;  is  of  a  pale  yellow  colour,  sometimes 
approaching  that  of  gold,  a  circumstance 
which,  added  to  its  considerable  weight, 
often  attracts  the  attention  of  the  unskil- 
j  ful,  who  imagine  it  .to  contain  gold  Is 
!  gives  plenty  of  sparks  with  the  steel,  and 
\  emits  an  odour  of  sulphur.    In  the  fire  it 
j  cracks  or  decrepitates,  burns  with  a  blue 
!  flame,  and  assumes  a  dull  brown  colour  s 
!  in  the  air  it  effloresces,  is  decomposed,  its 
]  sulphur  becomes  acidified,  unites  with  the 
|  iron  and  clay  which  are  present  in  its 
composition,  and  with  these  forms  suiphat 
j  of  iron  and  alum,  for  the  obtaining  both 
of  which  this  mineral  is  wrought.   Its  va~ 
jrieties  are, 


ORE 


ORE 


1.  In  irregular  masses. 

2.  In  balls  of  various  sizes  disseminated 
in  chalk. 

3.  In  stalactites. 

4.  In  cubes,  frequently  found  in  clay. 

5.  In  hard  crystals  called  marcasite- 
The  brown  or  reddish-brown  ferrugi- 
nous pyrites  is  called  the  hepatic  iron  ore. 
It  is  either  spherical,  or  in  cubes,  or  other 
regular  forms ;  has  no  metallic  lustre, 
does  not  easily  give  fire  with  steel,  and  is 
incapable  of  being  converted  to  a  sulphat. 
It  contains  much  less  sulphur  and  more 
iron  than  the  yellow  pyrites,  but  the  me- 
tal it  yields  is  brittle. 

Gray  iron  ore  has  a  shining  metallic  ap- 
pearance, and  commonly  gives  fire  with 
steel.  It  is  not  at  all  magnetic,  and,  when 
scratched,  gives  a  red  trace.  It  yields 
from  40  to  66  per  cent,  of  cold  short  iron. 
This  property  is  derived  from  phospho- 
rus, or  its  acid,  which  exists  in  the  ore. 

Plumbago  is  a  carburet  of  iron. 

A  cupreous  arseniat  of  iron,  in  very 


logons  to  the  artificial  Prussian  blue,  dif- 
fers nevertheless  from  it  in  intensity,  by 
the  manner  of  its  production,  and  other 
peculiar  qualities.  It  preserves  its  co- 
lour in  water,  but  becomes  black  in  oils. 

For  the  methods  of  analysis  of  the  ores- 
of  iron,  as  well  as  its  chemical  properties 
and  several  states,  see  the  article  Iron. 
But  from  the  extensive  importance  of  this 
metal,  we  shall  here  add  the  methods  of 
treatment  in  the  large  way. 

Most  ores  of  iron  require  to  be  roasted 
previously  to  their  fusion  ;  some  more 
slightly,  and  others  with  a  more  violent 
and  longer  continued  fire.  Those  which 
contain  much  sulphur,  arsenic,  or  sulphu- 
ric acid,  require  a  long  continued  and  re- 
peated rousting,  that  the  volatile  matters 
may  be  expelled.  Of  this  kind  is  the 
black  iron  ore,  from  which  the  Swedish 
iron  is  said  to  be  obtained. 

Some  ores  require  a  very  slight  roast- 
ing, only  that  they  may  be  dried  and  ren- 
dered friable ;  such  are  the  ores  called 


brilliant  and  transparent  crystals,  of  a  bog  ores :  and  others,  which  being  in  an 
faint  sky-blue  colour,  has  been  described  j  oxided  state,  and  containing  little  sulphu- 


by  the  count  de  Bournon,  and  analysed 
by  Mr.  Chenevix.  It  contains,  in  lOt) 
parts,  oxide  of  iron  27.5,  oxide  of  copper 
22.5,  arsenic  acid  33.5,  silex  3,  water  12. 
Specific  gravity,  3.  4.  Another,  in  which 
Mr.  Chenevix  considers  the  copper  as 
merely  accidental,  was  of  a  dark  green, 
with  a  brownish  tinge,  and  sometimes  yel- 
lowish ;  tolerably  transparent ;  and  scarce- 
ly so  hard  as  the  preceding,  being  barely  j 


reous  matter,  wotdd,  by  a  farther  oxida- 
tion, be  rendeied  less  capable  of  being 
reduced  to  a  metallic  state. 

The  roasting  of  ores  of  iron  is  perform- 
ed by  kindling  piles,  consisting  of  strata 
of  fuel  and  of  ore  placed  alternately  up- 
on one  another,  or  in  furnaces  similar  to 
those  commonly  employed  for  the  calci- 
nation of  limestone. 

The  next  operation  is  the  fusion  or 
able  to  scratch  calcareous  spar.  This  gave  I  smelting  of  the  ore.  This  is  generally 
oxide  of  iron  45  5,  oxide  of  copper  9,  J  performed  in  blast  furnaces  or  towers 


arsenic  acid  31,  silex  4,  water  10.5.    Spe-  (  ft 
cific  gravity  3.    They  were  both  from 
Cornwall. 


om  twenty  to  thirty  feet  high,  in  the  bot- 
tom of  which  is  a  basin  for  the  reception 
When  the  furnace  is 


of  the  fluid  metal. 


A  blue  combination  of  iron  is  found  in- '  sufficiently  heated,  which  must  be  done 
terspersed  in  clays,  in  Finland,  Scania,  j  at  fi;  st  very  gradually,  to  prevent  the 
and  elsewhere.  Bergman  palls  it  Native  ;  cracking  of  the  walls;  a  quantity  of  the 
Prussian  Blue.  Sometimes  the  clays  have  '  ore  is  to  be  thrown  in,  from  time  to  time, 
a  blue  colour  at  the  surface,  and  some- '  at  the  top  of  the  furnace,  along  with  a 
tim«  s  they  assume  that  colour  soon  after  certain  quantity  of  fuel  and  of  lime-stone, 
beiiii,  'dug  out  of  the  ground.  It  is  easily  or  whatever  other  flux  is  employed, 
seen,  that  the  ore  is  ferruginous,  and 
highly  loaded  with  combustible  matter  ; 
for  it  burns  with  a  flame,  and  becomes 


red  and  magnetical.    A  mild  heat  ren- 


While  the  fuel  below  is  consumed  by  the 
fire  excited  by  the  wind  of  the  bellows, 
the  ore,  together  with  its  proportionable 
quantity  of  fuel  and  of  flux,  sink  gra- 


ders this  substance  green,  and  a  stronger  dually  down,  till  they  are  exposed  to  the 
converts  it  into  black  scoria.  Alkalies,  as  greatest  heat  in  the  furnace.  There  the 
well  as  acids,  dissolve  this  blue  powder,  ore  and  the  flux  are  fused,  the  metallic 
and  destroy  its  colour,  which  nevertheless  particles  are  revived  by  the  fuel,  precipi- 
appears  again  when  precipitated  from  an  tated  by  means  of  their  weight  through 
acid  by  an  alkali,  or  by  an  alkali  from  an  the*  scoris  formed  of  the  lighter  earthy 
acid  ;  but  commonly  it  is  greenish,  and  parts  of  the  flux  and  of  the  ore,  and 
soon  becomes  white.  If  an  infusion  of  unite  in  the  basin  at  the  bottom  of  the  fur- 
tea  or  nut-galls  be  poured  on  this  whitish  nace,  forming  a  mass  of  fluid  meta  ,  co- 
scu.lu  nt,  it  resumes  its  first  colour,  vered  by  a  glassy  scoria.  When  a  sujfi- 
From  these  details  it  appears,  as  Berg-  cknt  quantity  of  this  fluid  metal  is  col- 
man  remarks,  th>it  this  blue,  though  ana-  j  lected,  which  is  generally  twice  or  thrice 


ORE 


ORE 


in  twenty -four  hours,  an  aperture  is  made, 
through-  which  the  metal  flows  into  a 
channel  or  groove  nude  in  a  bed  of"  sand  ; 
and  thence  into  smaller  lateral  or  con- 
nected channels,  or  other  moulds.  There 
it  is  cooled^  becomes  solid,  and  retains 
the  forms  of  the  channels  or  moulds  into 
which  ii  flows. 

The  piece  of  iron  formed  in  the  large 
channel  is  called  a  sow,  and  those  formed 
in  the  smaller  channels  are  called  pigs. 
Sometimes  the  fluid  iron  is  taken  out  of 
the  furnace  by  means  of  ladles,  and  pour- 
ed  into  moulds,  ready  prepared,  of  sand 
or  of  clay,  and  is  thus  formed  into  the  va- 
rious utensils  and  instruments  for  which 
cast  iron  is  a  proper  material. 

The  scoria  must  be  from  time  to  time 
allowed  to  flow  out,  when  a  considerable 
quantity  is  formed,  through  an  aperture 
made  in  the  front  of  the  furnace  for  this 
purpose.  A  sufficient  quantity  of  it  must, 
how  ever,  be  always  left  to  cover  the  sur- 
face of  the  melted  iron ;  else  the  ore 
which  would  fall  upon  it,  before  the  sepa- 
ration of"  its  metallic  from  its  unmetallic 
parts,  would  lessen  the  fluidity  and  injure 
the  purity  of  the  melted  metal.  This  sco- 
ria ought  to  have  a  certain  degree  of"  flu- 
idity ;  for  if  it  be  too  thick,  the  revived 
metallic  particles  will  not  be  able  to  over- 
come its  tenacity,  and  collect  together  into 
drops,  or  be  precipitated.  Accordingly, 
a  scoria,  not  sufficiently  fluid,  is  always 
found  to  contain  much  metal.  If  the  sco- 
ria be  too  thin,  the  metallic  particles  of 
the  ore  will  be  precipitated  before  they 
are  sufficiently  metallized,  and  separated 
from  the  earthy  and  unmetallic  pans  A 
due  degree  of  fluidity  is  given  to  the  sco- 
ria, by  applying  a  proper  heat,  and  by 
adding  fluxes  suited  to  the  ore 

Some  ores  are  fusible  without  addition, 
and  others  cannot  be  melted  without  the 
addition  of  substances  capable  of  facili- 
tating their  fusion. 

The  fusible  ores  are  those  which  con- 
tain sulphur,  arsenic,  or  are  mixed  with 
some  fusible  earth. 

The  ores  difficultly  fusible  are, 

1.  Those  which  contain  no  mixture  of 
other  substance.  Such  are  most  of  the 
ores  which  contain  iron  in  a  state  nearly 
metallic.  As  iron  itself,  when  purified 
from  all  heterogeneous  matters,  is  sea  ce- 
ly  fusible  without  addition,  so  the  metal 
contained  in  these  purer  kinds  of  ores  can- 
not be  easily  extracted,  without  the  addi- 
tion of  some  fusible  substance. 

2.  Those  which  are  mixed  with  some 
very  refractory  substance.  Some  of  these 
refractory  ores  contain  arsenic ;  but  as 
this  substance  facilitates  the  fusion  of 
iron,  we  may  presume,  that  their  refrac- 

VOL.  TI, 


tory  quality  depends  upon  a  mixture  of 
some  unmetallic  earth  or  other  unfusible 
substance.  The  earth  which  is  mixed 
with  the  common  calciform  ores  is  in 
considerable  quantity,  and  is  sometimes 
calcareous,  sometimes  siliceous,  and  some- 
times argillaceous.  Most  of  the  iron 
stones  wrought  in  this  country  have  a 
mixture  of  all  three,  but  in  variable  pro- 
portions, and  according  as  one  or  other  is 
predominant,  a  greater  or  less  proportion 
of  flux  is  required. 

Keir  thinks  it  probable,  that  the  fusibil- 
ity of  some  ores  may  greatly  depend  on 
the  degree  of  oxidation  to  which  the  me- 
tal contained  in  them  has  been  reduced ; 
since  we  have  reason  to  believe,  that,  by  a 
very  perfect  oxidation,  some  metals,  at 
least;  may  be  reduced  to  the  state  of  be- 
ing almost  infusible,  and  scarcely  capable 
of  reduction  ;  and  since  we  know,  that  in 
every  oxidation  and  subsequent  reduction 
of  a  given  quantity  of  any  imperfect  me- 
tal, a  perceptible  part  of  that  quantity  is 
always  lost  or  destroyed,  however  care- 
fully these  operations  may  have  been  per- 
formed. That  some  of  these  ores  are  al- 
ready too  much  oxided,  appears  from  the 
instance  above  mentioned  of  the  bog  ores, 
which  are  injured  by  roasting;  and  even 
the  great  height  of  the  common  smelting 
furnaces,  although  advantageous  to  many 
ores  that  require  much  roasting,  is  said 
to  be  injurious  to  those  which  are  already 
too  much  oxided,  by  exposing  them  to  a 
farther  oxidation,  during  their  very  gra- 
dual descent,  before  they  arrive  at  the 
hottest  part  of  the  furnace,  where  they 
are  fused. 

Rut,  as  too  violent  calcination  renders 
some  ores  difficultly  fusible ;  so  too  slight 
calcination  of  other  ores  injures  the  puri- 
ty of  the  metal,  by  leaving  much  of  the 
sulphureous  or  other  volatile  matter, 
which  ought  to  have  been  expelled. 

Various  substances  are  added  to  assist 
the  fusion  of  ores  difficultly  fusible.  These 
are  : 

1.  Ores  of  a  fusible  quality,  or  which, 
being  mixed  with  others  of  a  very  differ- 
ent quality,  become  fusible :  accordingly, 
in  the  great  works  for  smelting  ores  of 
iron,  two  or  more  different  kinds  of  ores 
are  commonly  mixed,  to  facilitate  the  fu-' 
sion,  and  also  to  meliorate  the  quality  of 
the  iron.  Thus  an  ore  yielding  an  iron 
which  is  brittle  when  hot,  which  quality 
is  called  red-short,  and  another  ore  which 
produces  iron  brittle  when  cold,  or  cold- 
short, are  often  mixed  together ;  not,  as 
is  sometimes  supposed,  that  these  quali- 
ties are  mutually  destructive  of  each 
other,  but  that  each  of  them  is  diminish- 
ed in  the  mixed  mass  of  iron,  as  much  a9 
r?  c 


ORE 


ORE 


this  mass  is  larger  than  the  part  of  the 
mass  originally  possessed  of  that  quality 
Thus,  if  from  two  such  ores  the  mass  of 
iron  obtained  consists  of  equal  parts  of 
cold-short  and  of  red-short  iron,  it  will 
have  both  these  qualities,  but  will  be  on- 
ly half  as  cold-short  as  iron  obtained  sole- 
ly from  one  of  the  ores,  and  half  as  red- 
short  as  iron  obtained  only  from  the  other 
ore. 

2.  Earths  and  stones  arc  also  generally 
added  to  facilitate  the  fusion  of  iron  ores. 
These  are  such  as  are  fusible,  or  become 
fusible  when  mixed  with  the  ore,  or  with 
the  earth  adhering  to  it.  Authors  direct, 
that,  if  the  earth  of  the  ore  be  of  an  ar- 
gillaceous or  siliceous  nature,  lime-stone 
or  aome  calcareous  earth  should  be  add- 
ed ;  and  that  if  the  adherent  earth  be 
calcareous,  an  argillaceous  or  siliceous 
earth  should  be  added;  because  these 
two  earths,'  though  singly  infusible,  j  et, 
when  mixed,  mutually  promote  the  fu- 
sion of  each  other:  but  we  believe  lime- 
stone is  the  only  addition  ever  made,  be- 
side i he  fuel. 

The  fuel  generally  used  on  the  conti- 
nent of  Europe  for  smelting  ores  of  iron 
is  charcoal :  but  in  almost  all  the  works 
in  England  and  Scotland,  iron  ore  is 
smelted  by  means  of  pit-coal,  previously 
reduced  to  cinders  or  coke,  by  a  kind  of 
calcination  similar  to  the  operation  for 
converting  wood  into  charcoal.  In  France, 
pit-coal  not  charred  has  been  tried  for 
this  purpose,  but  unsuccessfully.  The 
use  of  peat  lias  also  been  introduced  in 
some  parts  of  England. 

The  quaht)  of  the  iron  depends  consi- 
derably upon  the  quality,  and  also  upon 
the  quantity,  of  the  fuel  employed.  Char- 
coal is  fitter  than  coke  for  producing  an 
iron  capable  of  being  rendered  malleable 
by  forging. 

The-  quantity  of  fuel,  or  the  intensity  of 
the  heat,  must  be  suited  to  the  greater  or 
less  fusibility  of  die  ore.  Sulphureous  and 
other  ores  easily  fusible  require  less  fuel 
than  ores  difficultly  fusible.  In  general, 
if  the  quantity  of  fuel  be  too  small,  and 
the  heat  not  sufficiently  intense,  all  the 
iron  wih  not  be  reduced,  and  much  of  it 
will  remain  in  the  scoria,  which  will  not 
be  sufficiently  thin. 

This  defect  of  fuel  may  be  known  by 
the  blackness  and  compactness  of  the 
scori:>,  by  the  qualities  of  the  iron  obtain- 
ed, which  in  this  case  is  hard,  white,  light, 
intermixed  with  scoria,  smooth  in  its  tex- 
ture, without  scales  or  grains,  rough  and 
convex  on  its  surface,  and  liable  to  great 
loss  of  weight  by  being  forged ;  and  last- 
ly, it  may  be  known  by  observing  the  co- 
lour and  appearance  of  the  drops  of  me- 


tal falling  down  from  the  smelted  ore, 

and  of  the  scoria  upon  the  sui  ace  of  the 
fluid  metal,  both  which  are  darker  colour- 
ed than  when  more  fuel  is  used. 

When  the  quantity  of  fuel  is  sufficient- 
ly large,  and  the  heat  is  intense  enough, 
the  iron  is  darker  coloured,  denser,  more 
tenacious,  contains  less  scoria,  and  is 
therefore  less  fusible,  and  loses  less  of  its 
weight  by  being  forged.  Its  surface  is  al- 
so smoother  and  somewhat  concave  ;  and 
its  texture  is  generally  granulated  The 
scoria  in  this  case  is  of  a  lighter  colour 
and  less  dense.  The  drops  falling  from 
the  smelling  ore,  and  the  liquid  scoria  in. 
the  furnace,  appear  hotter  and  of  a  bright- 
er colour 

When  the  quantity  of  fuel  is  too  great, 
and  the  heat  too  intense,  the  iron  will  ap- 
pear to  have  a  still  darker  colour,  and 
more  conspicuous  grains  or  plates  ;  and 
the  scoria  will  be  lighter,  whiter,  and 
more  spongy.  The  drops  falling  from 
the  smelted  ore,  and  the  fluid  scoria,  will 
appear  to  a  person  looking  into  the  fur- 
nace through  the  black  hole  to  be  very 
white  and  shining  hot. 

The  quantity  of  charcoal  necessary  to 
produce  five  hundred  weight  of  iron, 
when  the  ore  is  rich,  the  furnace  well 
contrived,  and  the  operation  skilfully  con- 
ducted, is  computed  to  be  about  forty  cu- 
bic feet ;  but  is  much  more  in  contrary 
circumstances.  Mr.  Mushet  calculates, 
that,  if  a  calcined  iron  stone  affording  40 
per  cent,  of  iron,  1  cwt.  of  coke  from 
clod-coal  will  smelt  130  lbs.  producing 
52  lbs.  of  iron  ;  1  cwt.  of  coke  from  splint 
coal,  105  lbs.  yielding  42  lbs.  of  iron  ;  and 
1  cwt.  of  coke  from  hard  and  soft  coal 
mixed,  84  lbs  giving  33  6  lbs.  of  iron. 

The  time  during  which  the  fluid  metal 
ought  to  be  kept  in  fusion,  before  it  is  al- 
loxved  to  flow  out  of  the  furnace,  must  be 
also  attended  to.  In  some  works  the  me- 
tal is  allowed  to  flow  out  of  the  furnace 
every  six  or  eight,  and  in  some  others  on- 
ly every  ten  or  twelve,  hours.  Some  work  - 
men imagine,  that  a  considerable  time  is 
necessary  for  the  concoction  of  the  me- 
tal. This  is  certain,  that  the  iron  under- 
goes some  change  by  being  kept  in  a  fluid 
state ;  and  that,  if  its  fusion  be  prolonged 
much  beyond  the  usual  time,  it  is  render- 
ed less  fluid,  and  also  its  cohesion,  when 
it  becomes  cold,  is  thereby  greatly  dimi- 
nished. The  quantity  of  iron  daily  ob- 
tained from  sucli  a  furnace  as  is  above  de- 
scribed, is  from  two  to  five  tons,  accord- 
ing to  the  richness  and  fusibility  of  the 
ore,  to  the  construction  of  the  furnace,  to 
the  adjustment  of  the  due  quantity  of 
flux  and  of  fuel,  and  to  the  skill  employ 
ed  in  conducting  the  operation. 


OttE 


OJ1E 


The  quality  of  the  iron  is  judged  by 
observing-  the  appearances  during-  its 
flowing  from  the  furnace,  and  when  it  is 
fj\ed  and  cold.  If  the  fluid  iron,  while  it 
flows,  emits  many  and  large  sparkles ;  if 
many  brown  spots  appear  on  it  while  it  is 
yet  red-hot ;  if,  when  it  is  fixed  and  cold, 
its  corners  and  edges  a>  e  thick  and  rough, 
and  its  surface  is  thick  and  spotted;  it  is 
known  to  have  a  red-short  quality.  If,  in 
flowing,  the  iron  seems  covered  with  a 
thin  glassy  crust,  and  if,  when  cold,  its 
texture  be  whitish,  it  is  believed  to  be 
cold-short.  Reaumur  sa\s,  that  dark-co- 
loured cast-iron  is  more  impure  than  that 
which  is  white.  The  marquis  de  Courti- 
vron  is  of  a  contrary  opinion. 

But  no  certain  rules  for  judging  of  the 
quality  of  iron  before  it  is  forged  can  be 
given.  From  brittle  cast-iron  sometimes 
ductile  forged-iron  is  produced.  Cast- 
iron  with  brilliant  plates  and  points,  when 
fo;  ged,  becomes  sometimes  red-short,  and 
sometimes  cold-short.  Large  shining 
plates,  large  cavities  called  eyes,  want  of 
sufficient  density,  are  almost  certain 
marks  of  bad  iron  ;  but  whether  it  will  be 
cold  or  red-short,  cannot  be  affirmed,  till 
it  is  forged.  Whiteness  of  colour,  brit- 
tleness,  closeness  of  texture,  and  hard- 
ness, are  given  to  almost  any  cast-iron  by 
sudden  cooling;  and  we  may  observe, 
that  in  general,  the  whiter  the  metal  is, 
the  harder  it  is  also,  whether  these  pro- 
perties proceed  from  the  quality  of  the 
iron,  or  from  sudden  cooling ;  and  that, 
therefore,  the  darker-coloured  iron  is  fit- 
ter for  being  cast  into  moulds,  because  it 
seems  capable  of  being  filed  and  polish- 
ed, especially  after  it  has  been  exposed, 
during  several  hours,  to  a  red  heat  in  a 
reverberatory  furnace,  and  very  gradually 
cooled.  This  operation,  called  by  the 
workmen  annealing,  changes  the  texture 
of  the  metal,  renders  it  softer,  and  more' 
capable  of  being  filed  than  before,  and  al- 
so considerably  less  brittle. 

It  is  in  fact  capable  of  being  softe-^d 
by  annealing,  and  hardened  by  sudden 
cooling  like  steel,  through  the  heat  regain- 
ed, for  these  changes  are  greater.  Many 
artists  avail  themselves  of  this  property  to 
advantage.    See  Iron. 

In  Navarre,  and  in  some  of  the  southern 
parts  of  France,  iron  ore  is  smelted  in  fur- 
naces much  smaller,  and  of  a  very  differ- 
ent construction  from  those  above  de- 
scribed. A  furnace  of  this  kind  consists 
of  a  wide-mouthed  copper  caldron,  the  in- 
ner surface  of  which  is  lined  with  mason- 
ry a  foot  thick.  The  mouth  of  the  cal- 
dron is  nearly  of  an  oval  or  elliptic  form 
The  space  or  cavity  contained  by  the  ma- 
sonry is  the  furnace  in  which  the  ore  is 


smelted.  The  depth  of  this  cavity  is 
equal  to  two  feet  and  a  half;  the  larger 
diameter  of  the  oval  mou^h  of  the  cavity 
is  about  eight  feet ;  and  its  smaller  diame- 
ter is  about  six  feet :  the  space  of  the  fur- 
nace is  gradually  contracted  towards  the 
bottom,  the  greatest  diameter  of  which 
does  not  exceed  six  feet:  eighteen  inches 
above,  the  bottom  is  a  cylindrical  channel 
in  one  of  the  longer  sides  of  the  caldron 
and  masonry,  through  which  the  nozzle 
of  the  bellows  passes.  This  channel,  and 
also  the  bellows-pipe,  are  so  inclined,  that 
the  wind  is  directed  towards  the  lowest 
point  of  the  opposite  side  of  the  furnace. 
Another  cylindrical  channel  is  in  one  of 
the  shorter  sides  of  the  furnace,  at  the 
height  of  a  few  inches  from  the  bottom, 
which  is  generally  kept  closed,  and  is 
opened  occasionally  to  give  passage  to 
the  scoria ;  and  above  this  is  a  third  chan- 
nel, in  the  same  side  of  the  furnace, 
through  which  an  iron  instrument  is  occa- 
sionally introduced  to  stir  the  fluid  metal, 
and  to  assist,  as  is  said,  the  separation  of 
the  scoria  from  it  The  greatest  height 
of  this  channel  is  at  its  external  aperture 
on  the  outside  of  the  furnace,  and  its 
smaller  height  is  at  its  internal  aperture, 
so  that  the  instrument  may  be  directed 
towards  the  bottom  of  the  furnace ;  but 
the  second  channel  below  it  has  a  con- 
trary inclination,  that  when  an  opening  is 
made,  the  scoria  may  flow  out  of  the  fur- 
nace into  a  bason  placed  for  its  reception. 

When  the  furnace  is  heated  sufficient- 
ly, the  workmen  begin  to  throw  into  it  al- 
ternate charges  of  charcoal,  and  of  ore 
previously  roasted.  They  take  care  to 
throw  the  charcoal  chiefly  on  that  side 

which  the  wind  enters,  and  the  ore  at 
the  opposite  side.  At  the  end  of  about 
four  hours  a  mass  of  iron  is  collected  at 
the  bottom  of  the  furnace,  which  is  gene 
rally  about  six  hundred  weight ;  the  bel- 
lows are  then  stopped;  and  when  the 
mass  of  iron  is  become  solid,  the  work- 
men raise  it  from  the  bottom  of  the  fur- 
nace, and  place  it,  while  yet  soft,  under  a 
large  hammer,  where  it  is  forged.  The 
iron  produced  in  these  furnaces  is  of  the 
best  quality ;  the  quantity  is  also  very 
considerable,  in  proportion  to  the  quan- 
tity of  ore,  and  to  the  quantity  of  fuel  em- 
ployed. In  these  furnaces  no  lime-stone 
or  other  substance  is  used  to  facilitate  the 
fusion  of  the  ore 

We  should  receive  much  instruction 
concerning  the  smelting  of  iron  ore,  if  we 
knew  upon  what  part  of  the  process  or 
circumstance  the  excellence  of  the  iron 
obtained  in  these  furnaces  depends ;  whe- 
ther on  the  quality  of  the  ore  ;  on  the  dis- 
use of  any  kind  of  flux,  by  which  the  pro 


ORE 


ORE 


portion  of  vitreous  or  earthy  matter,  in- 
termixed with  the  metallic  particles,  is 
diminished  ;  on  the  forging  while  the  iron 
is  yet  soft  and  hot,  as  the  marquis  de 
Courtivron  thinks ;  or  on  some  other  cause 
not  ohserved. 

To  separate  the  impurities  from  cast 
iron,  and  to  unite  the  metallic  parts  more 
closely  and  compactly,  and  thus  to  give  it 
the  ductility  and  tenacity  which  render 
this  metal  more  useful  than  any  other,  are 
the  effects  produced  by  the  following  ope- 
rations : 

The  first  of  these  operations  is  a  fusion 
of  the  iron,  by  which  much  of  its  impuri- 
ties is  separated  in  form  of  scoria ;  and  by 
the  second  operation,  a  farther  and  more 
complete  separation  of  these  impurities, 
and  also  a  closer  compaction  of  the  metal- 
lic particles,  are  effected  by  the  applica- 
tion of  mechanical  force  or  pressure,  by 
means  of  large  hammers 

Some  differences  in  the  construction  of 
the  forge  or  furnace,  in  which  the  fusion 
or  refining  of  cast  iron  is  performed,  in 
the  method  of  conducting  the  operation, 
and  in  some  other  circumstances,  are  ob- 
served to  occur  in  different  places.  The 
following  is  the  German  method : 

The  fusion  of  the  cast  iron,  which  is  to 
be  rendered  malleable,  is  performed  upon 
the  hearth  of  a  forge  similar  to  that  used 
by  blacksmiths  :  at  one  side  of  this  hearth 
is  formed  a  cavity  or  fire-place,  which  is 
intended  to  contain  the  fuel  and  the  iron 
to  be  melted :  this  fire-place  is  twenty 
inches  long,  eighteen  inches  broad,  and 
twelve  or  fourteen  inches  deep  ;  it  is 
bounded  on  three  sides  by  three  plates  of 
cast  iron,  placed  upright;  and  on  the 
fourth  side,  which  is  the  front,  or  that  part 
nearest  to  which  the  workmen  stand,  by 
a  large  forge  hammer,  through  the  eye  of 
which  the  scoria  is  at  certain  times  allow- 
ed to  flow.  The  floor  also  of  the  fire-place 
is  another  cast  iron  plate.  The  thickness 
of  these  plates  is  from  two  to  four  inches. 
One  of  the  upright  side  plates  rests  againsl 
a  wall,  in  an  aperture  through  which  a 
copper  tube,  called  the  tuyere,  is  luted 
with  clay.  This  tube  is  a  kind  of  case  or 
cohering  for  the  pipe  of  a  pair  of  bellows 
placed  behind  the  wall,  and  its  direction 
is  therefore  parallel  to  that  of  the  bellows- 
pipe;  but  it  advances  about  half  a  foot 
farther  than  this  pipe  into  the  fire-place, 
and  thus  gives  greater  force  to  the  air, 
which  it  keeps  concentrated,  or  prevents 
the  divergency  of  the  air,  till  it  is  requi- 
site to  act.  The  tube  rests  upon  the  up- 
per  edge  of  the  side-plate  which  leans 
against  the  waii,  nearer  to  the  back  part 
than  to  the  front  of  the  fire -place,  and  in 
such  an  oblique  direction,  that  the  wind  I 


shall  be  impelled  towards  the  farthest 
part  of  the  floor  of  the  fire-place,  or  where 
this  floor  is  intersected  by  the  opposite 
side-plate.  The  obliquity  of  the  tuyere 
ought  to  vary  according  to  the  quality  of 
the  iron ;  and  therefore,  in  every  opera- 
tion it  may  be  shifted  till  its  proper  posi- 
tion is  found.  The  more  nearly  its  direc- 
tion approaches  to  a  horizontal  plane,  the 
more  intense  is  the  heat ;  but  a  larger 
quantity  of  fuel  is  consumed  than  is  even 
proportional  to  the  increase  of  heat,  be- 
cause the  flame  is  not  then  so  well  con- 
fined. When  the  iron  is  easily  fusible, 
great  heat  is  not  required;  the  tuyere 
may  then  decline  considerably  from  the 
horizontal  plane,  and  thus  fuel  may  be 
saved.  This  tuyere,  though  made  of  cop- 
per, a  metal  more  easily  fusible  than  iron, 
is  preserved  from  fusion  by  the  constant 
passage  of  cold  air  through  it.  It  must 
be  carefully  kept  open,  and  cleansed  from 
the  scoria,  which  would  be  apt  to  block 
its  cavity,  by  which  not  only  the  heat 
would  be  too  much  diminished  for  the 
success  of  the  operation,  but  the  tube  it- 
self would  be  melted. 

To  prepare  for  the  fusion,  a  quantity  of 
scoria  of  a  former  operation  is  thrown  into 
the  fire-place,  till  one  third  part  of  this  is 
full ;  and  then  the  remaining  two  thirds 
of  the  fire-place  are  to  be  filled  with 
smaller  scoriae,  coal-dust,  and  sparks  eject- 
ed from  hot  iron.  These  matters,  being 
fusible,  form  a  bath  for  the  reception  of 
the  iron  when  melted.  Upon  this  bed  of 
scoria  the  mass  of  cast  iron  to  be  melted 
is  placed;  so  that  one  end  of  it  shall  be 
within  the  fire-place,  opposite  to  the  tuy- 
ere, and  at  the  distance  of  about  four  or 
five  inches  from  its  aperture ;  and  the 
other  end  shall  stand  without  the  fi  e- 
place,  to  be  pushed  in  as  the  former  is 
melted.  The  upper  side  of  the  mass  of 
iron  ought  to  be  m  the  same  horizontal 
plane  as  the  upper  part  of  the  orifice  of 
the  tuyere,  that  the  wind  may,  by  means 
of  the  obliquity  of  its  course,  strike  upon 
and  pass  along  the  under  side  of  the 
mass :  but  if  the  iron  be  difficultly  fusi- 
ble, the  tuyere  is  to  be  disposed  more  ho- 
rizontally, so  that  the  wind  shall  strike 
directly  upon  the  mass  of  iron  ;  and  that 
one  part  of  the  blast  shall  graze  along 
the  upper  surface,  and  the  other  part 
along  the  under  surface  of  the  iron.  The 
mass  of  iron  weighs  generally  from  00 
to  400  pounds,  bometimes  two  or  three 
smaller  masses  are  put  one  above  another, 
so  as  not  to  touch.  When  these  are  of 
different  qualities,  the  cold-short  piece  is 
place d^mdermost,  that  being  less  fusible 
than  tne  red-short.  The  iron  be.ng  placed, 
charcoal  powder  is  thrown  on  both  sides; 


ORE 


ORE 


and  coals  are  accumulated  above,  so  as 
entirely  to  cover  the  iron. 

The  coals  are  then  to  be  kindled,  and 
the  bellows  are  made  to  blow,  at  first 
slowly,  and  afterwards  with  gradually  in- 
c reused  force-  The  iron  is  liquefied  by 
degrees,  and  flows  down  in  drops  through 
the  melted  scoria  to  the  bottom  or  the 
fire-place ;  during  which  the  workmen 
frequently  turn  the  iron,  so  that  the  end 
opposed  to  the  blast  of  wind  may  be 
equally  exposed  to  heat,  and  uniformly 
fused.  While  the  coals  are  consuming, 
more  are  thrown  on,  so  that  the  whole 
may  be  kept  quite  covered.  During  the 
operation,  a  workman  frequently  sounds 
the  bottom  and  corners  of  the  five-place, 
by  means  of  a  bar  or  poker,  raises  up  any 
muss  of  metal  which  he  finds  adhering  to 
these,  and  exposes  them  to  the  greatest 
heat,  that  they  may  be  more  perfectly 
fused. 

When  all  the  iron  is  fused,  no  more 
coals  are  to  be  added,  but  the  melted 
mass  is  to  remain  half  uncovered  for  some 
time ;  during  which  the  iron  boils  and 
bubbles,  and  its  surface  swells  and  rises 
higher  and  higher.  When  the  iron  has 
risen  as  high  as  the  upper  edge  of  the  fire- 
place, the  coals  upon  its  surface  must  be 
removed ;  and  by  thus  exposing  it  to  cold 
air,  its  ebullition  and  swelling  subside-  In 
this  state,  or  coction,  the  iron  is  kept  du- 
ring half  an  hour  or  more,  by  adding  oc- 
casionally pieces  of  good  coal,  which 
maintain  a  sufficient  heat,  without  cover- 
ing entirely  the  surface  of  the  mass.  Du- 
ring this  coction,  the  workmen  allow  the 
orifice  of  the  tuyere  to  be  half  stopped  up 
by  the  scoria,  that  the  air  may  not  blow 
upon  the  iron  with  all  its  force,  by  which 
it  would  be  too  much  cooled.  According- 
ly, when  they  think  that  the  coction  has 
continued  sufficiently  long,  they  clear  the 
passage  of  the  tuyere,  and  the  mass  is 
soon  cooled  by  the  cold  air :  at  the  same 
time  also,  they  open  a  passage  in  the  eye 
of  the  hammer  placed  in  the  front  of  the 
fire-place,  through  which  some  of  the  sco- 
ria is  allowed  to  flow  out.  When  the  iron 
has  become  solid,  the  bellows  are  stop- 
ped, the  coals  are  removed,  and  the  mass 
is  left  during  an  hour:  and  then  the  work- 
men raise  it  from  the  fire-place,  turn  it 
upside  down,  and  proceed  to  the  second 
coction  or  fusion  of  the  iron. 

For  this  second  operation,  the  mass  is 
to  be  so  placed,  that  one  part  of  it  shall 
rest  upon  the  tuyere,  and  the  other  upon 
the  scoria  remaining  in  the  fire-place. 
This  scoria  is  to  be  disposed  in  an  oblique 
direction,  parallel  to  the  tuyere,  by  winch 
means  the  wind  of  the  bellows  is  obliged 
to  pass  all  along  the  under  <=ide  of  the 


mass  of  iron.  About  the  sides  of  the 
mass,  charcoal-powder  and  burnt  ashes 
are  thrown;  but  toward  the  tuyere,  dry 
and  entire  pieces  of  coals  are  placed  to 
maintain  the  fire.  When  these  are  kin- 
dled, more  coals  are  added,  and  the  fire 
is  gradually  excited  The  workman  at- 
tends to  the  direction  of  the  flame,  that 
it  may  pass  equally  along  under  the  sur- 
face of  the  iron,  quite  to  the  faither  extre- 
mity ;  and  that  it  do  not  escape  at  the 
sides,  or  be  reverberated  back  toward  the 
tuye«es  by  which  this  copper  tube  might 
be  melted.  During  this  fusion,  pieces  of 
iron  are  apt  to  be  separated  from  the 
mass,  and  to  fall  down  unfused  to  the  bot- 
tom and  corners  of  the  fire-place.  These 
are  carefully  to  be  searched  for,  and  ex- 
posed to  the  greatest  heat  till  they  are 
melted  When  the  whole  mass  is  thus 
brought  into  perfect  fusion,  the  coals  are 
removed,  and  the  wind  blowing  on  its  sur- 
face, whirls  and  dissipates  the  small  re- 
maining pieces  of  scoria,  and  sparks 
thrown  out  from  the  fluid  iron.  1  his  jet 
of  fire  continues  about  seven  or  eight  mi- 
nutes, and  the  whole  operation  about  two 
hours.  In  this  second  fusion  the  scoria  is 
to  be  thrice  removed,  by  opening  a  pas- 
sage through  the  eye  of  the  hammer. 
The  first  time  of  removing  the  scoria  is 
about  twenty  minutes  from  the  kindling 
of  the  fire  ;  the  second  time  is  about  forty- 
minutes  after  the  first ;  and  the  third  time 
is  near  the  end  of  the  operation. 

The  mass  is  then  removed  from  the 
hearth,  and  put  upon  the  ground  of  the 
forge,  where  it  is  cleaned  from  scoria,  and 
beaten  into  a  more  uniform  shape.  It  is 
then  placed  on  an  anvil,  where,  by  being 
forged,  it  receives  a  form  nearly  cubical. 
This  mass  is  to  be  divided  into'  five,  six, 
or  more  pieces,  by  means  of  a  wedge ; 
and  these  are  to  be  heated  and  forged  till 
they  are  reduced  to  the  form  of  the  bars 
commonly  sold. 

In  some  forges  the  iron  is  fused  only 
once,  and  in  others  it  suffers  three  fusions, 
by  which  it  is  said  to  be  rendered  very 
pure.  Where  only  one  fusion  is  practised, 
it  is  called  the  French  method.  In  this 
no  greater  quantity  of  iron  is  fused  at 
once,  than  is  sufficient  to  make  one  bar. 
The  fire-place  is  of  considerably  less  di- 
mensions, and  especially  is  less  deep  than 
in  the  German  method  above  described. 
The  fire  is  also  more  inten.se,  and  the  pro- 
portion of  fuel  consumed  to  the  iron  is 
greater.  The  iron,  when  melted,  is  not 
kept  in  a  state  of  ebullition,  as  is  above 
described-  but  this  ebullition  is  prevent- 
ed by  stirring  the  fluid  mass  with  an  iron 
bar,  till  it  is  coagulated  and  becomes 
solid. 


ORE 


ORE 


By  these  operations,  fusion  and  forging, 
the  iron  loses  about  two-thirteenth  parts 
of  its  former  weight,  sometimes  more,  and 
sometimes  less,  according  to  the  quality 
of  the  cast  iron  employed;  its  metallic 
particles  are  more  closely  compacted,  its 
texture  is  changed,  and  it  is  rendered 
more  dense,  soft,  and  malleable,  tough, 
and  difficultly  fusible. 

The  degrees,  however,  of  these  quali- 
ties vary  much  in  different  kinds  of  iron 
Thus  some  iron  is  tough  and  malleable, 
both  when  it  is  hot,  and  when  it  is  cold. 
This  is  the  best  and  most  useful  iron.  It 
may  be  known  generally  by  the  equable 
surface  of  the  forged  bar,  which  is  free 
from  transverse  fissures  or  cracks  in  the 
edges  ;  and  by  a  clear,  white,  small-grain- 
ed, or  rather  fibrous  texture  Another 
kind  is  tough  when  it  is  heated,  but  brit- 
tle when  it  is  cold.  This  is  called  cold- 
short iron,,  and  is  generally  known  by  a 
texture  consisting  of  large  shining  plates, 
without  any  fibres.  It  is  less  liable  to  rust 
than  other  iron.  A  third  kind  of  iron,  call- 
ed red-short,  is  brittle  when  hot,  and  mal- 
leable when  cold.  On  the  surface  and 
edges  of  the  bars  of  this  kind  of  iron, 
transverse  cracks  or  fissures  may  be  seen; 
and  its  internal  colour  is  dull  and  dark. 
It  is  very  liable  to  rust.  Lastly,  some  iron 
is  brittle,  both  when  hot  and  cold. 

In  one  bar  frequently  two  or  more  dif- 
ferent kinds  of  iron  may  be  observed, 
which  run  all  along  its  whole  length ;  and 
scarcely  a  bar  is  ever  found  of  entirely 
pure  and  homogeneous  iron.  This  differ- 
ence probably  proceeds  from  the  practice 
we  have  mentioned  of  mixing  different 
kinds  of  ores  together  in  the  smelting,  and 
also  from  the  practice  of  mixing  two  or 
more  pigs  of  cast  iron  of  different  quali- 
ties in  the  finery  of  these  j  by  which  means 
the  red-short  and  the  cold-short  qualities 
of  the  different  kinds  are  not,  as  we  have 
already  remarked,  mutually  counteracted 
or  destroyed  by  each  other ;  but  each  of 
these  qualities  is  diminished  in  the  mixed 
mass  of  iron,  as  much  as  this  mass  is 
larger  than  the  part  of  the  mass  originally 
possessed  of  that  quality.  For  these  dif- 
ferent kinds  of  iron  seem  as  if  they  were 
only  capable  of  being  interwoven  and  dif- 
fused through  each  other  but  not  of  being 
intimately  united  or  combined. 

The  quality  of  forged  iron  may  be 
known  by  the  texture  which  appears  on 
breaking  a  bar  The  best  and  toughest 
iron  is  "that  which  has  the  most  fibrous 
texture,  and  is  of  a  clear  grayi-.li  colour. 
This  fibrous  appearance  is  given  by  the 
resistance  which  the  particles  of  the  iron 
make  to  their  rupture.  The  next  best 
iron  is  that,  the  texture  of  which  consists 


of  clear  whitish  small  grains,  intermixed 
with  fibres.  These  two  kinds  are  mallea- 
ble, both  when  hot  and  when  cold,  and 
have  great  tenacity.  Cold-short  iron  is 
known  by  a  texture  consisting  of  large 
shining  plates  without  fibres;  and  red- 
short  iron  is  distinguished  by  its  dark  dull 
colour,  and  by  the  transverse  cracks  and 
fissures  on  the  surface  and  edges  of  the 
bars  The  quality  of  iron  may  be  much 
improved  by  violent  compression,  as  by 
forging  and  rolling,  especially  when  it  is 
not  long  exposed  to  too  violent  heat,  which 
is  known  to  injure,  and  at  length  to  de- 
stroy, its  metallic  properties. 

In  January,  1806,  Mr.  Descotils  read  to 
the  mathematical  and  physical  class  of  the 
French  National  Institute  a  memoir,  in 
which  he  proved  by  experiments,  that  the 
iron  spar,  which  was  the  subject  of  it,  va- 
ried in  the  proportions  of  its  constituent 
principles ;  and  hence  he  explained  the 
differences  that  the  ores  require  in  their 
metal  lurgic  treatment  The  difficulty  of 
fusing  some  of  them  constituted  at  that 
time  the  principal  object  of  his  research  ; 
and  the  comparative  analysis  he  made  led 
him  to  the  conclusion,  that  the  magnesia, 
which  is  frequently  found  in  them  in  large 
quantity,  was  the  cause  of  their  refracto- 
riness. 

Reflecting  on  the  processes  adopted  to 
deprive  these  ores,  of  the  principle  of 
their  infusibility,  which  consist  chiefly  in 
exposure  to  tf«e  air  and  rain,  either  before 
or  after  roasting,  Mr.  Descotils  conjec- 
tured, that  these  processes  had  no  other 
effect,  than  that  of  separating  the  mag- 
nesia. 

In  the  first  case,  that  is  to  say,  when 
these  ores  were  exposed  to  the  air  before 
roasting,  he  supposed,  that  this  earth  was 
dissolved  in  the  state  of  carbonat  by  the 
rain.  In  the  second,  on  the  contrary,  he 
ascribed  this  effect  to  the  sulphuric  acid, 
developed  by  the  efflorescence  of  the  py- 
rites, with  which  the  iron  spar  is  almost 
always  accompanied. 

Since  that  period,  Mr.  Descotils  has 
communicated  to  this  assembly,  a  second 
memoir,  in  which  he  furnishes  substantial 
proofs  of  the  explanations  he  has  offered 
in  the  former  paper,  as  merely  conjectu- 
ral ;  at  the  same  time  avails  himself  of 
them,  to  answer  some  objections,  that  had 
been  advanced  by  Mr.  Hassenfratz.  The 
latter  gentleman,  however,  after  having 
made  some  fresh  experiments  and  obser- 
vations, has  withdrawn  his  memoir,  which 
the  class  has  referred  to  the  same  com- 
mittee :  we  shall  not  therefore  enter  into 
any  discussion  of  the  points,on  which  these 
two  learned  chemists  differed,  but  shall 
consider  the  facts  related  by  Mr.  Desco- 


ORE 


ORE 


tils,  and  the  conclusion  lie  has  deduced 
from  them,  as  if  they  had  never  been  dis- 
puted. 

On  the  second  occasion,  Mr.  Descotils 
has  repeated  his  former  experiments, 
•  hicli  gave  him  the  same  results.  He  has 
likewise  made  new  ones ;  and  all  mutual- 
ly supporting  each  other,  have  only  con 
firmed  him  in  his  opinion.  But  let  us  re- 
late some  of  these  experiments. 

He  exposed  10  the  lire,  a  mixture  of  15 
parts  of  magnesia,  and  100  parts  of  iron 
ore,  from  die  isle  of  Elba,  finely  powder- 
ed ;  and  the  result  lie  obtained  was  per- 
fectly similar  to  what  every  magnesian 
iron  spar  had  furnished  him. 

To  ascertain  whether  the  division  of  the 
particles  of  the  substance  had  any  influ- 
ence on  its  fusibility,  he  made  a  trial  with 
part  of  the  same  specimen,  of  iron  ore  of 
Elba,  without  wasting  or  powdering1  it, 
and  he  obtained  a  perfectly  compact  but- 
ton, at  a  degree  of  heat,  similar  to  what 
would  have  been  requisite,  for  an  assay 
of  earthy  iron  ore,  with  the  addition  of 
borax. 

(This  fact  shews,  says  the  author,  that 
cohesion  does  not  diminish  the  fusibility 
of  iron  ores  ;  at  least,  if  this  cohesion  can 
be  estimated,  by  the  hardness  of  the  ore, 
and  the  resistance  it  offers  to  the  action 
of  acids,  for  none  possess  these  two  quali- 
ties in  a  more  striking"  degree,  than  the 
iron  crystals  of  the  isle  of  Elba.  The 
committee  are  of  a  similar  opinion,  only 
the  fusion  must  require  so  much  longer 
time,  in  proportion  as  the  ore  is  in  frag- 
ments, of  a  larger  bulk. 

Mr.  Descotils  could  have  wished  to  ana- 
lise  specimens  of  refractory  iron  spar, 
comparatively  with  specimens  of  the  same 
ore,  become  fusible  by  exposure  to  the 
air  :  but  not  having  been  able  to  procure 
any,  he  thought  he  might  supply  their 
place  by  two  pieces,  from  the  same  vein, 
one  of  which  was  not  altered,  the  other 
had  passed  to  the  state  of  a  free  ore. 

Without  describing  the  method  he  em- 
ployed for  this  purpose,  which  we  consi- 
der as  very  accurate,  we  shall  only  say, 
that  he  found  the  decomposed  ore,  no 
longer  contained  any  magnesia  or  carbo- 
nic acid,  while  the  other  contained  four 
per  cent,  of  carbonic  acid,  and  magne- 
sia. 

The  analysis  of  five  other  specimens,  of 
free  ores,  from  different  places,  gave  him 
the  same  results  ;  whence  he  concludes, 
that  the  separation  of  the  magnesia  is 
complete,  when  the  decomposition  of  the 
ores  is  complete. 

In  some  cases  he  suspects,  that  it  is  to 
the  efflorescence  of  the  pyrites,  from 
which  scarcely  any  sparry  iron  ore  is  free, 


that  the  solution  and  abstraction  of  the 
magnesia  of  the  raw  ore,  is  owing  ;  since 
sulphat  of  magnesia  is  sometimes  to  be 
observed  on  heaps  of  ore,  of  an  analogous 
nature,  exposed  to  the  air,  as  well  as  in 
the  waters,  with  which  these  ores  are 
washed ;  and  he  has  obtained  similar  re- 
sults in  a  small  way,  by  putting  magne- 
sian iron  spar  in  powder,  into  a  solution  of 
suiphat  of  iron. 

He  believes,  however,  that  it  is  most 
frequently  the  carbonic  acid,  which,  disen- 
gaged from  the  iron,  in  proportion  as  this 
absorbs  oxygen,  dissolves  and  carries  off 
the  magne  sia  by  means  of  water. 

As  to  the  change  effected  in  the  roast- 
ed ore,  by  exposure  to  the  air  and  rain,  the 
conjectures  of  Mr.  Descotils  are  confirm- 
ed by  analysing  the  waters,  with  which  a 
heap  of  roasted  ore,  long  exposed  to  the 
air,  had  been  washed  These  waters  con- 
tained nothing  but  sulphat  of  magnesia, 
and  a  little  sulphat  of  lime;  which  salts 
could  have  been  produced  only  by  the  ac- 
tion of  the  sulphuric  acid,  arising  from  the 
pyrites,  on  the  earthy  substances  contain- 
ed in  the  ore. 

Mr.  Descotils  quotes  letters  of  several 
well-informed  persons,  and  worthy  of  cre- 
dit, who,  in  agreeing  on  the  point,  that 
sparry  iron  orts,  recently  extracted  and 
roasted,  are  more  difficult  of  fusion,  and 
less  productive,  than  those  that  have  re- 
mained three  or  four  years  in  the  open  air, 
give  still  more  force  to  his  theory. 

Though  it  is  certain,  that  the  presence 
of  magnesia  in  iron  ores,  diminishes  their 
fusibility  more  or  less,  the  author  of  the 
memoirs  observes,  however,  that,  if  it  be 
accompanied  with  a  sufficient  quantity  of 
lime,  siiex,  and  alumine,  or  of  oxide  of 
manganese,  it  is  not  so  injurious,  because 
il  becomes  fusible,  by  combining  with 
these  substances. 

Conceiving  the  advantage  iron-masters 
would  find,  in  having  an  easy  method  of 
knowing  by  simple  inspection,  a  free  from 
a  refractory  ore,  Mr.  Descotils  has  exa- 
mined, whether  among  the  external  cha- 
racteristics of  these  substances,  there 
might  not  be  some,  by  which  these  pro- 
perties could  be  distinguished  :  but  the 
strictest  scrutiny,  in  this  respect,was  with- 
out success  He  has  been  obliged,  there- 
fore, to  have  recourse  to  chemical  means, 
and  what  he  found  most  to  the  purpose, 
was  fusing  the  ore  without  the  addhiou 
of  any  flux. 

ii\  after  this  operation,  the  matter  pre- 
sent itself,  m  a  grayish,  earthy,  friable 
mass,  interspersed  with  small  globules  of 
cast  iron,  it  is  a  proof,  that  the  ore  is  mag 
nesian.and  consequently  more  or  less  re- 
fractory . 


ORE 


ORE 


But,  on  the  contrary,  if  a  well  fused 
button  be  obtained,  with  brown  and  not 
very  abundant  scoria;,  the  ore  is  fusible, 
and  contains  but  little  magnesia. 

When  the  scoriae  are  green,  they  indi- 
cate the  presence  of  oxide  of  manganese, 
part  of  which  is  reduced,  and  mixes  with 
the  cast  iron,  by  a  high  and  long  continu- 
ed heat 

The  least  altered  kinds  of  sparry  ores, 
that  Mr.  Descotils-  assayed,  lost  in  roast- 
ing from  31  to  37  per  cent.  The  altered  or 
free  ores  lost  at  most,  but  14  per  cent,  and 
this  loss  was  merely  water. 

The  quantities  of  magnesia  and  man- 
ganese vary  greatly :  sometimes  there  may 
be  12  per  cent  of  either  in  the  raw  ore, 
and  at  others,  there  is  scarcely  any. 

From  the  results  of  his  analysis  Mr. 
Descotils  concludes,  that  a  high  propor- 
tion of  one,  excludes  a  high  proportion  of 
the  other,  without  the  absence  of  the  one 
necessarily  indicating  the  presence  of  the 
other :  so  that  the  iron,  when  brought  to 
the  state  of*  red  oxide,  always  amounts  to 
50  per  cent,  at  least. 

Hence  Mr.  Descotils  explains  -what 
takes  place  in  theCatalonian  forges,  where 
the  different  species  of  ores  are  treated, 
according  to  the  nature,  number,  and 
quantity  of  the  principles  they  contain. 
He  points  out  the  method  that  each  re- 
quires, and  the  product  they  afford,  ac- 
cording as  the  operation  is  conducted. 
Sometimes  it  is  cast  steel,  at  others  mal- 
leable iron,  or  some  mixture  of  the  two. 
On  this  occasion,  he  expresses  his  sur- 
prise, that  no  one  has  yet  thought  of  esta- 
blishing a  manufactory  of  cast-steel  in  the 
Pyrenees. 

He  thinks  justly,  that  all  rich  iron  ores, 
which  contain  but  few  earthy  parts,  such 
as  those  of  the  island  of  Elba,  might  be 
fused  with  advantage,  in  the  Catalonian 
method. 

It  follows  evidently,  from  the  experi- 
ments of  Mr.  Descotils,  that  certain  kinds 
of  sparry  ores,  owe  their  infusibility  to  the 
presence  of  a  large  quantity  of  magnesia : 
and  that  the  principal  object  of  the  expo- 
sure of  these  ores,  to  the  air  and  rain,  ei- 
ther before  or  after  roasting,  is  xo  separate 
the  magnesia,  and  render  them  fusible- 
The  various  experiments  we  have  witness- 
ed, and  the  results  which  we  have  seen, 
leave  us  no  doubt  on  this  head  :  since  on 
the  one  hand,  the  ores  in  which  there  is 
no  magnesia,  are  easy  of  fusion,  and  those 
which  contain  a  certain  proportion,  are 
wholly  infusible  ;  while  on  the  other,  the 
addition  of  magnesia  to  fusible  ores,  di- 
vests them  of  this  property,  and  infusible 
ores,  when  their  magnesia  is  abstracted 
from  them,  become  fusible. 


From  the  observations  of  Mr.  Descotils* 
it  farther  follows,  that  there  is  no  exiei  nal 
character,  by  whicn  we  can  distinguish, 
whether  a  sparry  iron  ore,  be  fusibie  or 
not :  but  he  has  pointed  out  chemical 
means  of  determining  their  nature,  which 
are  easy  m  practice. 

The  following  processes  from  Cramer 
and  Gellert;,  are  sufficient  to  direct  the 
assay  of  iron  ores,  in  the  furnace. 

Process  I.  - 

T o  reduce  or  precipitate  iron,  out  of  its  ore, 
in  a  close  vessel. 

Roast  for  a  few  minutes  in  a  test,  under 
a  muffle,  and  with  a  pretty  strong  fire, 
two  centners  of  the  small  weight  of  your 
iron  ore,  grossly  pulverised,  that  the  vola- 
tile matters  may  be  dissipated  in  part,  and 
the  ore  itself  be  softened,  in  case  it  should 
be  too  hard.  When  it  is  grown  cold,  beat 
it  extremely  fine,  and  roast  it  a  second 
time,  as  you  do  the  copper  ore,  but  in  a 
much  stronger  fire,  till  it  no  longer  emits 
any  smell ;  then  let  it  grow  cold  again. 
Compose  a  flux  of  three  parts  of  the  white 
fiux,  with  one  part  of  the  fusible  pulveris- 
ed glass,  or  of  the  like  sterile  unsulphu- 
reous  scoriee,  and  add  sandiver  and  coal- 
dust,  of  each  one  half  part ;  a*dd  of  this 
flux  three  times  the  quantity  of  your 
roasted  ore,  and  mix  the  whole  very  well 
together ;  then  choose  a  very  good  cruci- 
ble, well  rubbed  with  lute  within,  to  stop 
the  pores  which  may  remain  in  different 
places  unseen  ;  put  into  it  the  ore  mixed 
with  the  flux;  cover  it  over  with  common 
salt,  and  shut  it  close  with  a  tile,  and  with 
lute  applied  to  the  points. 

Put  the  wind-furnace  upon  its  bottom 
part,  having  a  bed  made  of  coal-dust.  In- 
troduce besides  into  the  furnace,  a  small 
grate  supported  on  its  iron  bars,  and  a 
stone  upon  it,  whereon  the  crucible  may 
stand,  as  on  a  support  ;  surround  the 
whole  with  hard  coals,  not  verj  large,  and 
kindle  them  at  top  :  when  the  vessel  be- 
gins to  grow  red,  which  is  indicated  by 
the  common  salt's  ceasing  to  crackle,  stop 
with  gross  lute,  the  holes  of  the  bottom 
part  of  the  furnace,  except  that  in  which 
the  nozzle  of  the  bellows  is  received; 
blow  the  fire,  and  excite  it  with  great 
force,  adding  now  and  then  fresh  fuel, 
that  the  vessel  may  never  be  naked  at  top . 
having  thus  continued  your  fire  in  its  full 
strength,  for  three  quarters  of  an  hour,  or 
for  a  whole  hour,  in  the  next  place,  take 
the  vessel  out  of  it,  and  strike  several  times 
the  pavement,  upon  which  it  is  set,  that 
the  small  g-ains  of  iron,  which  happen  to 
be  dispersed,  may  be  collected  into  a  but- 


ORE 


ORE 


ton,  which  you  will  find  after  having  brok- 
en the  vessel. 

When  the  button  is  weighed,  try  its 
malleability :  then  make  it  red-hot ;  and 
when  it  is  so,  strike  it  with  a  hammer : 
it"  it  bear  the  strokes  of  a  hammer, 
both  when  red-hot,  and  when  cold,  and 
extends  a  little,  you  may  pronounce  your 
iron  very  good  ;  but  if,  when  either  hot  or 
cold,  it  proves  brittle,  you  may  judge  it  to 
be  not  quite  pure,  but  still  partly  minera- 
lised. 

Remarks.  The  arsenic,  but  especially 
the  sulphur,  must  be  dissipated  by  roast- 
ing; for  the  former  renders  the  iron  brit- 
tle, and  the  latter  not  only  does  the  same, 
but  being  managed  in  a  close  vessel,  with 
a  saline  flux,  turns  to  an  alkaline  sulphu- 
ret;  which  acts  strongly  upon  the  iron, 
and  prevents  its  reduction  :  so  that  the 
whole,  or  great  part  of  it  at  least,  is  re- 
tained by  the  sulphureous  scoria  ;  in  this 
case  therefore,  it  is  generally  in  vain  to 
look  for  a  metallic  button. 

The  iron  obtained  from  this  first  preci- 
pitation, has  scarcely  ever  the  requisite 
ductility,  but  is  rather  brittle,  owing  to  the 
carbon  it  retains. 

Process  11. 

The  following  process  for  assaying  iron  ores, 
and  ferruginous  stones  and  earths,  is  ex- 
tracted from  Getter  ^s  Elements  of  Es- 
saying. 

Roast  two  quintals  of  iron  ore,  or  of  fer- 
ruginous earth  :  divide  the  roasted  mat- 
ter into  two  equal  parts  ;  to  each  of  which 
add  half  a  quintal  of  pulverised  glass,  if 
the  substance  be  fusible,  and  contain  much 
metal;  but  if  otherwise,  add  also  half  a 
quintal  of  calcined  borax.  If  the  roasting 
have  entirely  disengaged,  the  sulphur  and 
arsenic,  an  eighth  part,  or  even  half  a  quin- 
tal of  quicklime  may  be  added.  With  the 
above  matters  mix  12  pounds  of  charcoal 
powder. 

Take  a  good  crucible,  and  cover  the 
bottom,  and  sides  of  its  inner  surface  with 
a  paste,  made  of  three  parts  of  charcoal 
dust,  and  one  part  of  clay  beaten  together: 
in  the  hollow  left  in  this  paste,  put  the 
above  mixture,  press  it  lightly  down,  co- 
ver it  with  pulverised  glass,  and  put  on 
the  lid  of  the  crucible. 

Place  two  such  crucibles,  at  the  dis- 
tance of  about  four  fingers  from  the  air- 
pipe,  in  such  a  manner,  that  the  air  shall 
pass  betwixt  them,  at  about  the  third  part 
of  the  height  from  the  bottom ;  fill  the 
space  between  the  two  crucibles,  with 
coals  of  a  moderate  size ;  throw  lighted 
coals  upon  them,  that  the  fire  may  de- 
scend, and  make  them  red-hot,  from  top 

VOL.  II. 


to  bottom ;  at  first  let  the  bellows  blow 
softly,  and  afterwards  strongly,  during  an 
hour,  or  an  hour  and  a  quarter  ;  then  take 
away  the  Crucible,  and  break  it  when  cold. 
A  button  will  be  found  in  the  bottom,  and 
sometimes  some  small  grains  of  iron,  in  the 
scoria,  which  must  be  separated  and 
weiged  along  with  the  button ;  then  try 
the  button,  whether  it  can  be  extended  un- 
der the  hammer,  when  hot  and  when  cold. 

Jicmarks.  To  disengage  a  metal  from 
the  earthy  matters,  mixed  with  it  by  fire, 
we  must  change  these  matters,  into  scoria 
or  glass.  This  change  may  be  effected  by 
adding  some  substance,  capable  of  dis- 
solving these  matters  ;  that  is,  of  convert- 
ing them  into  scoria  or  glass,  from  which 
the  metallic  matters  may,  by  their  weight, 
separate  and  tbrm  a  button  at  bottom. 
Fixed  alkali,  which  is  an  ingredient  of  the 
black,  and  of  the  white  flux,  is  a  powerful 
solvent,  of  earths  and  stones  :  but  the  al- 
kali (by  the  assistance  of  sulphur)  does 
also  dissolve  iron,  especially  when  this 
metal  is  in  an  oxided  state  ;  and  the  solu- 
tion is  so  much  more  complete,  as  the  fire 
is  longer  applied.  Hence,  in  ordinary  as- 
says, where  an  alkaline  salt  is  used,  little 
or  no  iron  is  obtained.  Now,  glass  acts 
upon,  and  dissolves  earths  and  stones ;  but 
not,  or  at  least  in  a  very  small  degree, 
iron ;  consequently  glass  is  the  best  flux, 
for  such  assays ;  and  experience  confirms 
this  assertion.  If  the  ore  contain  but  little 
iron,  we  may  also  add  to  the  glass  some 
borax  ;  but  borax  cannot  be  employed 
singly,  because  it  very  soon  fuses  and  se- 
parates, from  the  ore  before  the  metal  is 
revived.  Quick -lime  is  added,  not  only  to 
absorb  the  sulphur  and  arsenic  remaining 
in  the  ore,  but  also  because  it  dissolves 
and  vitrifies,  the  stony  and  earthy  matters 
of  iron  .ores,  which  are  generally  argilla- 
ceous. For  which  reason,  in  the  large 
operations  for  smelting  iron  ore,  lime- 
stone, and  even,  in  certain  cases,  gypsum, 
are  commonly  added,  to  facilitate  the  fu- 
sion. 

The  reduction  of  iron  ore,  and  even  the 
fusion  of  iron,  require  a  violent  and  long- 
continued  heat ;  and  therefore  in  this  ope- 
ration, we  must  not  employ  an  inflamma- 
ble substance,  as  pitch,  that  is  soon  con- 
sumed ;  but  charcoal  pulverised,  which 
in  close  vessels,  is  not  sensibly  wasted. 
Too  much  charcoal  must  not  be  added, 
else  it  will  prevent  the  action  of  the  glass, 
upon  the  earthy  matter  of  the  ore,  and 
consequently  the  separation  of  the  metal- 
lic part.  Experiments  convinced  Cra- 
mer, that  one  part  of  charcoal  dust,  to 
eight  parts  of  ore,  was  the  best  propor- 
tion. 

When  iron  is  surrounded  bv  charcoal, 


ORE 


ORE 


it  is  not  decomposed  or  destroyed;  hence  j  who  calls  this  the  pyritous  ore*  of  lead,  it 
the  iron  of  the  ore.  which  sinks  into  the  I  sometimes  occurs  in  the  form  of  a  white 


hollow  made  of  paste  of  charcoal  dust  and 
clay,  remains  there  unhurt.  The  clay  is 
added  in  this  paste  to  render  it  more  com- 
pact, and  to  keep  the  fluid  iron  collected 
together. 

The  air  is  directed  between  the  cruci- 
bles,, because,  if  it  were  thrown  directly 
upon'  them,  they  would  scarcely  be  able 
to  resist  the  heat  The  space  between 
the  air-pipe  a;d  the  crucibles  ought  to  be 
constantly  filled  with  charcoal,  to  pre  vent 
the  cold  air  from  touching  the  crucibles. 
Ductile  and  malleable  iron  is  seldom  ob- 
tained in  this  first  operation. 

Mr.  Mushet,  in  the  assay  of  iron-stone 
employs  only  bottle  glass,  chalk,  and 
charcoal ;  varying  their  proportions,  ac 
cording  to  the  nature  of  the  stone.  Sup 
posing  the  earths  to  be  in  the  proportion 
of,  clay  9,  lime  6,  silex  3  ;  to  four  parts  of 
ore  he  puts  glass  4,  chalk  2,  charcoal  0.5: 
when  clay  10,  siiex  7,  lime  3 ;  glass  4 
chalk  4,  charcoal  0.75  :  when  lime  14 
clay  6,  silex  4;  gluss  5,  chalk  1.5,  char- 
coal 0.75 :  when  lime  10,  silex  6,  clay  4 ; 
glass  4,  chalk  2,  charcoal  0-5:  "when  silex 
12,  clay  8,  lime  5;  glass  3,  chalk  2,  char 
r.oul  Q.75:  when  silex  10,  lime  7,  clay  5; 
glass  3,  chalk  3.5,  charcoal  0.75:  and 
when  neither  of  the  earths  predominates  ; 
glass  3.5,  chalk  2.5,  charcoal  0.5. 

For  other  particulars  respecting  the 
properties  of  iron,  and  the  treatment  of 
its  ores,  see  Iron. 

Ores  of  Lead. 
Lead  has  been  found  native  in  various 
parts  of  England,  and  elsewhere,  or  at 
ieast  in  the  metallic  state.   But  most  mi- 
neralogists question  the  existence  of  na- 
tive lead,  and  consider  the  specimens  pro- 
duced as  such,  to  be  either  the  produce 
of  ancient  founderies,  or  purer  kinds  of 
lead  ore.    Hence  we  may  conclude,  that 
the  unequivocal  specimens  of  native  lead 
are  scarce;  but  the  curious  specimen 
mentioned  by  Bomarc,  in  the  second  vo- 
lume of  his  Mineralogy,  quoted  by  Magel- 
lan, appears  to  be  decisive  in  favour  of 
the  existence  of  this  metal  in  a  native 
state.   It  was  in  the  collection  of  the 
Abbe  Nollin  at  Paris,  and  came  from  the 
lead  mines  of  Pompean,  near  Rennes,  in 
Brittany.  This  metal  was  very  malleable, 
could  fie  cut  with  a  knife  without  crumb- 
ling, and  easily  melted  over  the  flame  of 
a  candle.    It  weighed  about  two  pounds; 
was  imbedded  in  an  earthy  lead  ore  of  a 
reddish  colour,  and  had  a  slaty  vein,  that 
went  through  it. 

Lead  is  found  mineralized  by  the  sul- 
phuric acid.   According  to  Mr.  Monnet, 


ponderous  oxide,  soluble  in  16  or  18  times 
its  weight  of  water.  It  does  not  effervesce  , 
nor  is  it  soluble  in  other  acids  ;  it  may  be 
reduced  by  laying  it  on  a  burning  coal.  It 
originates  from  the  spontaneous  decom- 
position of  sulphuretted  lead  ores.  Mon. 
Mineral.  371.  According  to  Dr.  Wither- 
ing, it  is  found  in  great  quantity  in  the 
island  of  Anglesea,  but  united  to  iron, 
and  not  reducible  by  the  blowpipe  or 
charcoal ;  it  contains  70  per  cent,  of  lead. 
This  is  of  a  yellow  colour,  and  mixed  with 
clay. 

The  green  lead  ore,  discovered  by 
Gahn,  consists  of  lead  mineralized  by  the 
phosphoric  acid.  If  urged  by  the  blow- 
pipe, it  melts,  and  affords  an  opake  glo- 
bule without  reduction,  which  in  cooling 
assumes  a  polyhedral  form,  the  facets  of 
which,  though  apparently  plain,  are,  in 
fact,  composed  of  concentric  strise,  when 
observed  by  the  microscope. 

The  red-lead  spar  or  ore  consists  of 
lead  mineralized  by  chromic  acid,  and  has 
not  hitherto  been  found  elsewhere  than  at 
Catherineburgh,  in  Siberia.  Externally  it 
is  of  a  pale,  and  internally  of  a  deep  red 
colour,  and  for  the  most  part  crystallized 
in  rhomboidal  parallelopipeds,  or  irregu- 
lar pyramids.  According  to  Vauquelin, 
it  contains  nearly  65.12  of  oxide  of  lead, 
and  34.88  of  chromic  acid.  Mongez  men- 
tions a  lead  ore  of  a  greenish  yellow  co- 
lour, in  a  matrix  of  quartz,  coming  from 
Siberia,  which  Vauquelin  found  to  be  a 
chromat  likewise.  Lehman  and  Mongez 
had  both  supposed  the  lead  in  these  chro- 
mats  to  be  mineralized  by  arsenic. 

The  yellow  lead  ore  of  Carinthia  was 
found  by  Klaproth  to  be  a  molybdat.  By 
Mr.  Hatchett's  analysis,  100  parts  give 
lead  58.4,  molybdic  acid  38,  oxide  of  iron 
2,  with  a  small  proportion  of  silex.  Spec, 
grav.  5.092. 

A  beautiful  yellow  lead,  in  silky  fila- 
ments, very  slightly  flexible,  was  lately 
discovered  in  France  by  Mr.  Champeaux, 
which  is  a  combination  of  lead  with  ar- 
senic acid  or  oxide. 

The  calciform  lead  ores  contain  car^ 
bonic  acid,  which  is  considered  as  the  mi- 
neralizer.  They  effervese  with  acids,  and 
are  easily  reduced  on  the  charcoal.  Kir- 
wan  distinguishes  five  varieties. 

1.  White  lead  spar,  lead  ochre,  or  na~ 
tive  ceruss.  It  is  sometimes  transparent, 
but  generally  opake,  and  crystallized  in 
regular  forms,  of  a  laminar  or  striated  tex- 
ture. Lead  ochre,  or  native  ceruss,  is  the 
same  substance,  but  in  a  loose  form  or  in- 
durated and  shapeless ;  sometimes  it  is 
found  in  a  silky  form.  Both  contain  a  little 


OjRE 


ORE 


.iron,  and  sometimes  calcareous  earth  and 
argill.  Both  grow  red  hot  or  yellowish 
when  sufficiently  heated  They  effervesce 
with  acids,  and  afford  from  60  to  80  or 
90  per  cent,  of  lead.  Both  are  found  in 
Baittany,  Lorraine,  Germany  and  Eng- 
land. 

2.  Red,  brown,  or  yellow.  This  is  also 
found  either  regularly  crystallized,  or  in 
shapeless  masses,  or  in  powder.  It  differs 
from  the  former  only  by  containing  more 
iron.  That  in  powder  contains  a  mixture 
of  clay  It  affords  about  70  or  80  per  cent, 
of  lead. 

3.  Green.  Either  crystallized  in  nee- 
dles as  in  Brittany,  or  in  loose  powder  as 
in  Saxony,  but  mostly  adhering  to  or  in- 
vesting quartz.  It  owes  its  colour  to  iron, 
and  seldom  contains  copper. 

4.  Blueish.  This  is  also  sometimes 
crystallized,  sometimes  irregular. 

5.  Black.  The  most  uncommon  of  all, 
and  occurs  either  crystallized,  or  of  an  in- 
determinate form. 

Lead  mineralized  by  sulphur  is  the 
commonest  of  all  lead  ores.  It  is  known 
by  the  name  of  galena,  or  potters'  lead 
ore,  and  is  of  a  blueish  dark  lead  colour, 
formed  of  cubes  of  a  moderate  size,  or  in 
grains  of  a  cubic  figure,  the  corners  of 
which  have  been  cut  off ;  its  texture  is  la- 
mellar, and  its  hardness  variable :  the 
hardest  sort  containing  a  greater  mixture 
of  iron  or  quartz  ;  that  in  grains  is  thought 
to  be  the  richest  in  silver;  but  the  richest 
contains  only  about  one  or  1.5  per  cent.; 
that  is,  12  or  18  ounces  per  quintal :  tlie 
poorest  about  60  grains.  Ores  that  yield 
about  half  an  ounce  of  silver  per  quintal, 
are  barely  worth  the  cost  of  extracting- 
them  :  the  proportion  of  sulphur  to  lead 
in  this  ore  is  also  variable  within  the  limits 
of  15  and  25  per  cent. ;  that  which  contains 
least  is  called  bley  sch\veif,and  is  in  some 
degree  malleable.  The  proportion  of  lead 
is  from  83  to  45  per  cent,  by  reason  of  an 
accidental  mixture  of  quartz,  that  of  iron 
is  generally  very  small.  Dr.  Watson  re- 
marks, that  the  ores  which  are  poorest  in 
lead,  are  often  the  richest  in  silver.  Tie 
specific  gravity  of  galena  is  from  6  565  to 
7-786;  when  melted,  it  yields  a  veilow 
slag. 

The  antimonial  lead  ore  has  the  same 
colour  and  weight  as  galena,  but  its  struc- 
ture is  commonly  radiated  like  that  of  the 
ore  of  antimony.  Beside  the  more  accu- 
rate methods  of  humid  solution,  the  anti- 
mony may  be  easily  perceived,  though  in 
small  quantities,  by  the  white  and  abun- 
dant fumes  it  emits  in  roasting. 

In  the  smelting  of  ores  of  lead  they  may 
be  considered  either  as  pure,  that  is,  con- 1 


taining  no  mixture  of  other  metals,  or  they 
are  mixed  with  silver,  copper,  or  pyrites. 

Pure  ores  of  lead,  and  those  which  con- 
tain so  small  a  quantity  only  of  silver  as 
not  to  compensate  for  the  expense  of  ex- 
tracting the  nobler  metal,  may  be  smelted 
in  furnaces,  and  by  operations  similar  to 
those  used  at  Rammelsburg,  or  by  the  fol- 
lowing methods. 

1.  From  the  lead-ore  of  Willach  in  Ca- 
rinthia  a  great  part  of  the  lead  is  obtained 
by  a  kind  of  eliquation,  during  the  roast- 
ing of  the  ore.  For  this  purpose,  the  ore 
is  thrown  upon  several  strata  or  layers  of 
wood,  placed  in  a  calcining  or  reverbera- 
tory  furnace.  By  kindling  this  wood,  a 
great  part  of  the  lead  flows  out  of  the  ore, 
through  the  layers  of  fuel,  into  a  basin 
placed  for  its  reception.  The  ore  which 
is  thus  roasted  is  beaten  into  smaller 
pieces,  and  exposed  to  a  second  operation 
similar  to  the  former,  by  which  more  me- 
tal is  eliquated;  and  the  remaining  ore  is 
afterward  ground,  washed,  and  smelted 
in  the  ordinary  method. 

The  lead  of  Willach  is  the  purest  of 
any  known.  Schlutter  ascribes  its  great 
purity  to  the  method  used  in  extracting 
it,  by  which  the  most  fusible,  and  conse- 
quently the  purest  part  of  the  contained 
lead,  is  separated  from  any  less  fusible 
metal,  which  happens  to  be  mixed  with  it, 
and  which  remains  in  the  roasted  ore. 
This  method  requires  a  very  large  quan- 
tity of  wood. 

2.  In  England  lead  ores  are  smelted 
either  upon  a  hearth,  or  in  a  reverberato- 
ry  furnace,  called  a  cupel. 

In  the  first  of  these  methods,  charcoal 
is  employed  as  fuel,  and  the  fire  is  ex- 
cited by  bellows.  Small  quantities  of  fuel 
and  of  ore  are  thrown  alternately  and  fre- 
quently upon  the  hearth.  The  fusion  is 
very  speedily  effected  ;  and  the  lead  flows 
from  the  hearth  as  fast  as  it  is  separated 
from  the  ore. 

3.  In  the  second  method  practised  in 
England  pit-coal  is  used  as  fuel.  The  ore 
is  melted  by  means  of  the  flame  passing 
over  its  surface;  its  sulphur  is  burni  and 
dissipated,  while  the  metal  is  separated 
from  the  scoria,  and  collected  at  the  bot- 
tom of  the  furnace.  When  the  ore  is  well 
cleansed  and  pure,  no  addition  is  requi- 
site ;  but  when  it  is  mixed  with  calcareous 
or  earthy  matrix,  a  kind  of  riuor  or  fusible 
spar  found  in  the  mines  is  generally  add- 
ed, to  render  the  scoria  more  fluid,  and 
thereby  to  assist  tl>e  preparation  of  the 
metal.  When  the  fusion  has  continued 
about  eight  hours,  a  passage  in  the  side 
of  the  furnace  is  opened,  through  which 
the  liquid  lead  flows  into  an  iron  ciste1*:! 


ORE 


But  immediately  before  the  lead  is  allow- 
ed to  flow  out  of  the  furnace,  the  work- 
men throw  upon  the  liquid  mass  a  quan- 
tity of  slaked  quick-lime,  which  renders 
the  scoria  so  thick  and  tenacious,  that  it 
may  be  drawn  out  of  the  furnace  by  rakes. 

Schlutter  mentions  this  addition  of 
quick-lime  in  the  smelting  of  lead-ores  in 
England,  but  thinks  that  it  is  intended  to 
facilitate  the  fusion  of  the  ores  ;  whereas 
it  really  has  a  contrary  effect,  and  is  never 
added  till  near  the  end  of  the  operation, 
when  the  scoria  is  to  be  raked  from  the 
surface  of  the  metal. 

Ores  of  Manganese. 
From  the  extreme  disposition  of  man- 
ganese to  become  oxided,  it  is  hardly  to 
be  expected  that  the  metal  should  be 
found  native.  But  Mr.  Peyrouse  describes 
a  substance  of  this  kind  in  the  Journal  de 
Physique  for  1786,  which  appears  to  be 
native  manganese  from  the  following-  pro- 
perties. 

1.  Its  external  appearance,  colour  and 
figure  are  the  very  same  as  those  of  the 
metallic  manganese  reduced  by  art. 

2.  It  likewise  soils  the  fingers  when 
handled. 

3.  Its  substance  is  quite  pure,  having 
no  particles  that  are  in  the  least  attracted 
by  the  magnet. 

4  Its  texture  is  lamellated,  and  the  la- 
mella seem  to  affect  a  kind  of  divergence 
among  themselves. 

5.  It  has  the  very  same  metallic  bril- 
liancy as  the  artificial  manganese. 

6.  It  has  also  a  partial  malleability ; 
and,  when  repeatedly  hammered, 

7.  It  exhibits  a  kind  of  exfbliatiop, 
forming  itself  into  very  thin  leaves. 

8.  Its  opacity  and'^ensity  are  so  com- 
pletely similar  to  that"  of  the  artificial  re- 
guius,  that,  were  It  not  for  the  natural 
matrix  in  which  it:is  imbedded,  it  could 
not  be  at  all  distinguished  from  it. 

9-  This  ore  is  not  found  in  large  masses, 
or  in  a  solid  continued  body,  but  only  in 
lumps,  and  unconnected  clots,  enclosed 
and  intermixed  with  the  powdery  manga- 
nese ore. 

10  These  lumps  are  somewhat  flatten- 
ed, or  compressed  in  their  figure,  like  the 
artificial  ones,  though  they  are,  for  the 
most  part,  of  a  larger  size. 

11,  And  this  powdery  manganesian  ore, 
in  which  the  reguline  lumps  are  imbed- 
ded, has  an  argentine  hue,  which  seems 
to  countenance  the  suspicion  of  its  having 
been  acted  upon  by  the  violent  heat  of 
some  natural  deflagration  on  the  spot. 

It  was  found  among  the  iron  mines  of 
Sem,  in  the  valley  of  Vicdessos,  in  the 


county  of  Foix,  near  the  Pyrenean  moun 
tains. 

The  only  ores  of  manganese  yet  well 
known  are  its  oxides,  which  vary  greatly 
in  colour,  texture,  and  other  properties, 
both  from  their  degree  of  oxidation,  and 
from  foreign  admixtures.  They  are  like- 
wise crystallized,  amorphous,  or  of  va- 
rious shapes  ;  and  vary  in  specific  gravity 
from  3.233  to  4.81.  One  of  these  ores,  the 
garnet-shaped,  is  of  a  deep  hyacinthine 
red ;  when  undecayed,  very  resplendent, 
of  a  fine  diamond  lustre;  and  strongly 
transparent  on  the  edges.  It  consists  of 
oxide  of  manganese  35,  oxide  of  iron  14, 
silex  35,  alumine  14.25.  * 

A  carbonat  of  manganese  is  found  in 
the  mines  of  Nagyag  in  Transylvania,  and 
it  is  said  also  in  France,  and  in  Norway. 
It  is  in  masses  of  a  pale  rose  colour,  Which, 
as  it  is  acted  upon  by  the  air,  turns  to  a 
light  yellowish  brown.  It  is  void  of  lus- 
tre, hard  and  brittle.  Lampadius  found 
its  component  parts  to  be 

Oxide  of  manganese  48 
Carbonic  acid       -  49.2 
Oxide  of  iron     -       -  2.1 
Silex  -  -  0.9 

100.2 


To  analyse  these  ores,  they  should  be 
first  roasted  to  oxide  effectually  the  man- 
ganese, and  iron,  if  any ;  then  treated  with 
dilute  nitric  acid,  to  dissolve  the  earths ; 
the  residuum  should  then  be  treated  with 
muriatic  acid,  assisted  by  gentle  heat; 
and  ihe  solution  precipitated  by  carbonat 
of  soda. 

The  precipitate  will  be  oxide  of  manga- 
nese, and  of  iron,  if  the  latter  were  pre- 
sent, which  will  be  known  by  boiling  it  in 
a  concentrated  solution  of  potash,  as  this 
will  dissolve  the  manganese  only.  If  the 
ore  contained  barytes,  this  will  be  precipi- 
tated from  the  nitric  solution  by  sulphuric 
acid :  if  lime,  it  may  be  precipitated  by 
carbonat  of  potash. 

Ores  of  Mercury. 
Mercury  is  found  in  a  native  state  suf- 
ficiently distinguishable  from  every  other 
metallic  substance,  by  its  fluidity  in  every 
ordinary  temperature  of  the  habitable 
parts  of  the  globe.  Bergman  doubts  whe- 
ther it  be  ever  found  uncontaminated  by 
any  other  metal.  *  It  is  found  in  the  quick- 
silver mines  in  small  brilliant  globules, 
disseminated  in  different  gangues.  Mon- 
gez  asserts,  that  it  is  mostly  in  a  state  of 
great  purity.  Sometimes  it  is  collected 
in  the  cavities  of  rocks,  as  at  Idria  in 
Friuli,  Almaden  in  Spain,  and  in  Amen- 


ORE 


ORE 


ca :  and  in  other  instances  it  is  dissemi- 
nated in  the  earth,  in  clays,  or  adherent 
to  quartaose  stones,  pot-stone  mica,  or  else 
mixed  with  diff  erent  ores,  as  the  white  or 
red  silver  ores,  galena,  white  arsenic,  or 
cinnabar. 

Mercury  has  been  found  in  Sweden  and 
elsewhere  united  to  silver  in  the  form  of 
an  amalgam,  sometimes  crystallized. 

Mr.  Sage,  in  the  Journal  de  Physique 
for  1784,  mentions  a  native  oxide  of  mer- 
cury of  a  red-brown  colour,  difficult  of 
fracture,  presenting  a  granulated  texture 
more  red  than  externally.  It  frequently 
contains  running  mercury  in  its  interstices. 
Jiy  distillation,  it  yields  of  mercury  from 
20  to  80  per  cent.  It  contains,  a  small 
part  of  silver,  and  comes  from  Idria. 

Mercury  was  found  by  Mr.  Woulfe  at 
Obermoschei  in  the  duchy  of  Zweybrueck- 
on,  united  with  the  muriatic  and  sulphu- 
ric acids.  These  ores  have  a  spar-like  ap- 
pearance, and  are  either  bright  and  white, 
or  yellow  or  black  mixed  with  cinnabar  in 
a  stony  matrix.  The  muriatic  was  in  the 
state  of  corrosive  sublimate. 

The  ore  of  mercury  which  is  wrought 
in  the  large  way  is  Cinnabar.  It  is  a 
combination  of  mercury,  with  one  fourth 
of  its  weight  of  sulphur.  See  Cinnabar. 

There  are  other  impure  cinnabars,  par- 
ticularly one  containing  copper,  which  is 
of  a  blackish  gray  colour,  glassy  texture, 
and  decrepitates  strongly  when  heated. 
The  cinnabar  may  be  volatilized  by  heat, 
and  the  remaining  copper  shews  itself  by 
the  usual  tests.  The  ore  of  mercury  con- 
taining iron,  and  distinguished  by  the 
name  of  pyritous  mercurial  ore,  is  a  gray 
or  whitish  friable  substance  found  in  Dau- 
phiny,  and  afforded  Mr.  Monnet  one  part 
of  mercury,  less  than  half  a  part  of  silver, 
and  the  rest  was  iron,  cobalt,  arsenic,  and 
silver. 

Process  I. 

To  separate  Mercury  out  of  an  unsulpliu. 
reous  ore  by  distillation. 
Take  a  lump  of  the  pulverized  ore,  one 
common  pound,  which  must  stand  for  one 
centner ;  put  it  into  a  glass  retort  perfect- 
ly clean,  well  loricated,  or  coated  up  to 
half  the  length  of  its  neck  :  this  must  be 
vci'y  long,  and  turned  backwards  with 
such  a  declivity,  that  a  glass  recipient 
maybe  perpendicularly  applied  to  it:  but 
you  must  choose  a  retort  small  enough, 
that  the  belly  of  it  may  be  filled  hardly 
two-thirds  with  the  ore :  this  retort  must 
be  placed  so,  that  nothing  of  the  fluid  ad- 
herent to  the  neck  of  it,  may  fall  into  the 
cavity  of  the  belly,  but  that  the  whole  may 
run  forward  into  the  recipient.  Lastly, 


take  a  sitfall  recipient  full  of  cold  water : 
let  it  be  placed  perpendicularly,  and  re- 
ceive the  neck  of  the  retort  in  such  a  man- 
ner, that  the  extremity  of  it  may  be  hard- 
ly one  half  inch  immersed  in  the  water. 

Let  the  retort  be  surrounded  with  hot 
burning  Coals  placed  at  some  distance  in 
the  form  of  a  circle,  lest  the  vessel  should 
burst  by  too  sudden  a  heat :  then  by  de- 
grees bring  the  burning  coals  nearer  and 
nearer,  and  at  last  surround  the  whole  re- 
tort with  them  and  with  fresh  charcoal, 
that  it  may  grow  slightly  red-hot :  this 
fire  having  been  continued  for  an  hour,  let 
the  retort  cool  of  itself :  then  strike  the 
neck  of  it  gently,  that  the  large  drops 
which  are  always  adherent  to  it  may  fall 
into  the  recipient :  let  the  recipient  be  ta- 
ken away,  and  the  water  separated  from 
the  mercury  by  filtration,  and  let  the  mer- 
cury be  weighed.  This  operation  may  be 
more  conveniently  performed  in  a  sand 
bath;  in  which  case  the  pot  containing 
the  sand  must  be  red-hot,  and  the  retort 
be  able  to  touch  the  bottom  of  it  imme- 
diately; nor  is  it  then  necessary  that  the 
retort  be  loricated. 

Process  II. 

To  revive  mercury  from  a  sulphureous  or 
cinnabar  ore. 
Beat  your  ore  extremely  fine,  and  mix 
it  exactly  with  an  equal  proportion  of  iron 
filings,  not  rusty ;  and  proceed  to  distil  it 
with  the  same  apparatus  as  in  the  former 
process ;  but  urge  it  with  the  strongest 
fire  that  can  be  made. 

Cinnabar  may  be  separated  from  stones 
by  sublimation  as  follows.  Beat  it  to  a 
fine  powder,  and  put  it  into  a  small  nar- 
row glass  or  earthen  cucurbit,  of  the  bel- 
ly of  which  it  must  not  fill  more  than  one 
third  part :  stop  the  orifice  at  top  ;  this 
must  be  very  narrow,  to  hinder  the  free 
action  of  the  air.  Put  this  small  cucur- 
bit into  an  earthen  pot  above  two  inches 
in  diameter,  and  gather  sand  around  this 
pot  about  as  high  as  the  pulverized  ore 
rises  in  the  cucurbit.  Then  put  it  upon 
burning  coals  in  such  a  manner,  that  the 
bottom  of  the  pot  may  be  moderately  red- 
hot.  Thus  will  your  cinnabar  ascend,  and. 
form  a  solid  ponderous  ring,  which  must 
be  taken  out  by  breaking  the  vessel. 

Ores  of  Molybdena,  are  not  used  in  the 
arts. 

Ores  of  Nickel. 
This  semimetal  has  been  found  by  Rin- 
man  in  a  cobalt-mine  in  Hesse.  The  mi- 
neral is  very  ponderous,  and  of  a  livid  co- 
lour. When  pulverized  and  roasted  un- 
der a  muffle,  it  forms  a  green  excrescence, 
and  smokes ;  but  its  smoke  has  no  pecu- 


ORE 


ORE 


liar  smell,  and  no  sublimate,  whether 
sulphureous  or  arsenical,  can  be  caught. 
It  affords  a  green  solution  with  acids  ;  but 
a  polished  iron  plate  discovers  no  indica- 
tion of  copper. 

Nickel  is  also  found  in  the  state  of  ox- 
ide, afforded  by  the  decomposition  of  kup- 
fer  nickel.  It  usually  has  the  form  of  a 
green  efflorescence,  and  often  covers  the 
ores  which  contain  it.  Cronstedt  informs 
us,  that  it  is  found  at  Normark  in  Warme- 
land,  without  any  appearance  of  kupfer 
nickel,  in  a  clay  which  contained  much 
native  silver. 

The  ore  long-  distinguished  by  the  name 
of  kupfer  nickel,  before  the  discovery  of 
the  peculiar  metal  by  Cronstedt,  is  of  a 
reddish-yellow  colour,  and  of  the  texture 
and  appearance  of  a  slag,  or  else  of  a  fine 
granular  texture ;  or  lastly,  of  a  scaly  or 
lamellar  texture.  Its  brilliancy  in  some 
measure  resembles  that  of  the  common 
pyrites  This  ore  contains  nickel,  with 
iron,  cobalt,  and  arsenic,  mineralized  with 
sulphur.    See  Nickel. 

Ores  cf  Osmium. 
This  metal  has  been  found  hitherto  on- 
ly in  small  quantity  among  the  black 
powder  left  after  dissolving  platina. 

Ores  of  Palladium. 
This  too  has  been  found  only  with  Pla- 
tina. 

Ores  of  Platina. 
This  comes  to  us  in  an  impure  native 
state.    Its  ores,  if  any,  are  unknown. 

Ores  of  Rhodium. 
Rhodium  has  yet  occurred  only  in  the 
grains  of  crude  platina. 

Ores  of  Silver. 

The  great  value  of  this  metal  lias  occa- 
sioned its  ores  to  be  very  particularly  at- 
tended to,  and  enumerated. 

Native  silver  is  found  in  a  granular,  la- 
mellar, filamentous,  capillary,  arbores- 
cent, or  crystallized  form,  inhering  either 
in  sulphat  of  barytes,  lime-stone,  sulphat 
of  lime,  quartz,  chert,  flint,  serpentine, 
gneiss,  agate,  mica,  calcareous  spar,  py- 
rites, schistus,  clay,  &.c. ;  also  in  separate 
masses  of  various  sizes,  some  of  the 
weight  of  60  pounds,  in  or  near  the  veins 
of  most  metallic  substances,  particularly 
in  Peru,  and  frequently  in  various  parts  of 
Europe,  either  of  a  white,  brown,  or  yel- 
lowish colour. 

It  is  often  diffused  through  sand  and 
ochre,  also  in  gray  lime  stone  in  Lower 
Austria,  and  in  a  greenish  clay  near 
Schemnitz,  or  mixed  with  ochre,  clay,  and 
oxide  of  nickel. 


It  is  seldom  found  pure,  being  general- 
ly alloyed  with  copper,  and  sometimes 
with  a  small  proportion  of  gold,  iron,  or 
antimony,  and  sometimes  about  five  per 
cent,  of  arsenic  ;  it  is  separable  from  gold 
and  antimony  by  solution  in  nitric  acid ; 
from  copper  and  iron  by  precipitating  it 
by  the  muriatic  acid;  and  from  arsenic 
by  torrefaction.  Cronstedt  says  its  puri- 
ty is  generally  approaching  to  16  carats. 
Lewis  asserts,  that  it  never  exceeds  this 
fineness.  The  nativ:  silver  found  near 
Konigsberg  contains  so  much  gold,  as  to 
acquire  a  yellow  colour  from  it. 

Horn-silver,  or  corneous  silver  ore,  is 
of  a  whitish-gray,  or  dirty  yellow,  some- 
times semitransparent,  easily  cut  with  a 
knife,  fusible  even  by  the  flame  of  a  can- 
dle, and  assuming  a  violet  colour  by  the 
sun's  rays.  One  hundred  grains  contain 
from  28  to  74  of  real  siver.  In  some  ores 
the  muriat  is  mixed  with  67  per  cent,  of 
argil.  It  is  reducible  by  triturating  it 
with  about  its  own  weight  of  fixed  alkali 
with  a  little  water,  then  melting  the  whole 
in  a  crucible,  the  bottom  of  which  is  co- 
vered with  soda  well  pressed,  and  cover- 
ing the  mass  of  horn -silver  also  with  the 
soda. 

The  vitreous  silver  ore  (silberglasertz) 
is  mineralized  by  sulphur.  It  is  found  ei- 
ther in  solid  large  lumps,  or  inhering  in 
quartz,  spar,  gypsum,  gneiss,  pyrites, 
&c.;  of  a  lamellar,  granular,  or  capillary 
form  crystallized.  It  is  generally  of  a 
lead  colour  first,  but  grows  black  by  ex- 
posure to  the  air,  but  sometimes  gray  or 
black,  even  when  first  broken  ;  its  lami- 
na: are  flexible  and  ductile,  and  even 
malleable  in  some  degree,  and  so  soft, 
that  they  may  be  cut  with  a  knife ;  its 
specific  gravity  is  7.200.  It  is  one  of  the 
richest  of  the  silver  ores,  containing  about 
.85  of  metal. 

The  black  silver  ore,  schwartzgulde- 
nertz,  silbermulm,  is  considered  as  a  va- 
riety of  this. 

The  brittle  vitreous  silver  ore,  analysed 
by  Klaproth,  gave,  in  100  parts,  silver 
66.5,  antimony  10,  iron  5,  sulphur  12, 
copper  and  arsenic  about  0.5,  extraneous 
matter  from  the  mine  I. 

It  is  analysed  by  boiling  in  moderately 
dilute  nitric  acid,  using  about  25  times  its 
weight,  till  the  sulphur  is  quite  exhaust- 
ed. The  silver  is  precipitated  by  muria- 
tic acid,  or  common  salt.  The  Prussian 
alkali  will  show  if  any  other  metal  is  con- 
tained in  the  solution :  the  gold,  if  any, 
will  remain  undissolved;  fixed  alkalies 
will  precipitate  any  other  earthy  matters 
contained  in  the  solution. 

In  the  dry  way  it  may  be  reduced  by 
melting  it  with  the  blow-pipe  on  char- 


ORE 


OI1E 


coal ;  for  the  sulphur  is  dissipated,  and 
the  silver  remains  ;  or  by  melting  it  with 
one  eighth  of  its  weight  of  filings  of  iron, 
as  the  iron  will  take  up  the  sulphur,  and 
be  scorified. 

Silver  is  either  mineralized  by  a  small 
or  a  large  proportion  of  arsenic.  The  ore 
Which  is  mineralized  by  a  small  propor- 
tion of  arsenic  is  of  a  yellowish-white  co- 
lour, and  of  a  striated  texture,  resembling 
bismuth,  but  much  harder  ;  it  melts  very 
easily  ;  and  if  kept  in  fusion,  it  loses  its 
arsenic,  and  the  silver  remains  almost  en- 
tirely pure,  as  it  contains  but  very  little 
iron ;  it  contains  about  90  per  cent,  of  sil- 
ver, and  is  found  near  Quadanal  canal 
in  Spain. 

The  proportion  of  arsenic  in  that  silver 
ore,  which  is  mineralized  by  a  large  pro- 
portion of  it,  is  so  great,  that  it  would 
scarce  deserve  to  be  called  a  silver  ore,  if 
the  arsenic  were  not  easily  dissipated : 
the  quintal  contains  but  from  four  to  six 
ounces  of  silver :  it  is  very  soft,  and  easi- 
ly cut,  and  when  cut  has  a  brilliant  metal- 
lic appearance ;  it  consists  of  conchoidal 
laminae  ;  it  is  also  found  at  Quadanal  ca- 
nal. It  is  reduced  by  evaporating  the 
arsenic,  which  then  leaves  the  silver 
slightly  contaminated  with  iron. 

A  silver  ore  of  this  kind  analysed  by 
Klaproth,  gave  silver  12.75,  iron  44.25, 
arsenic  35,  antimony  4. 

The  red  silver  ore  (rothguldenertz)  is 
a  heavy,  shining  substance,  either  trans- 
parent or  opake,  mostly  of  a  crimson  or 
reddish  colour,  though  sometimes  gray 
or  blackish,  but  when  scraped  or  powder- 
ed always  reddish  ;  found  either  in  irre- 
gular masses,  or  crystallized  in  pyramids 
or  polygons,  or  dendritical,  or  plated,  or 
radiated  incrustations,  on  or  in  matrixes 
of  quartz,  flint,  spar,  pyrites,  sparry  iron 
ore,  lead  ore,  pyrites,  cobalt  ore,  jasper, 
gneiss,  &c.  When  radiated  or  striated,  it 
is  called  rothgulden  bluth.  In  the  fire  it 
crackles  and  melts  after  it  has  acquired  a 
red  heat,  with  an  arsenical  smell ;  it  deto- 
nates with  nitre  :  its  specific  gravity  is 
from  5.4  to  5.684.  Bergman  found  100 
grains  of  it  to  contain  60  of  silver,  27  of 
arsenic,  and  13  of  sulphur  ;  but  sometimes 
it  contains  even  70  per  cent,  of  silver.  The 
darkest  ores  are  the  richest,  and  these  of- 
ten contain  a  little  iron  ;  the  yellowest  are 
the  poorest;  the  most  yellow  does  not  be- 
long to  this  species,  being  in  tact  orpi- 
ment,  containing  six  or  seven  per  cent,  of 
silver. 

To  analyse  this  ore  in  the  moist  way, 
Bergman  advises  to  boil  it  after  it  is  re- 
duced to  a  very  fine  powder  in  dilute  ni- 
tvic  acid,  and  to  edulcorate  the  residuum 


very  carefully  which  contains  the  sulphur 
and  arsenic,  which  may  be  separated  by 
boiling  in  a  sufficient  quantity  of  aqua  re- 
gia:  if  the  sulphur  still  retain  any  muriat 
of  silver,  it  may  be  separated  by  pure  am- 
monia. 

In  the  dry  way,  it  is  reduced  after  tor- 
refaction  by  a  mixture  of  iron  and  lead  ; 
the  iron  takes  up  the  sulphur,  and  the 
lead  the  silver,  which  is  afterward  sepa- 
rated by  cupellation. 

Klaproth,  however,  denies  that  it  con- 
tains arsenic,  as  not  the  least  vestige  of  it 
was  to  be  found  in  a  bright  red  crystalline 
ore  from  the  Ilartz,  or  another  from  Frei- 
berg. The  former  gave  silver  60,  antimo- 
ny 20. 3,  sulphur  11.7,  concrete  sulphuric 
acid  8;  the  latter,  silver  62,  antimony 
18.5,  sulphur  11,  concrete  sulphuric  acid 
8.5.  The  sulphur  and  its  acid  he  sup- 
poses to  have  been  united  in  the  state  ot" 
an  oxide  of  sulphur  in  the  ore. 

Another  species  of  silver  ore  mineraliz- 
ed by  sulphur,  and  containing  a  large  pro- 
portion of  lead,  is  called  white  silver  ore, 
weissgultigertz  Analysed  by  Klaproth^ 
100  parts  gave  silver  20  4,  lead  48.06,  an 
timony  7.88,  iron  2.25,  sulphur  12  25,  alu- 
miue  7,  silex  0  25.  A  variety  of  this  dark 
white  silver  ore,  gave  silver  9.25,  lead  41, 
antimony  21.5,  iron  1.75,  sulphur  22,  alu- 
mine  1,  silex  0.75.  Klaproth  distin- 
guishes this  from  the  weissguldenertz  o* 
Kremnitz,  which,  has  been  confounded 
with  it,  and  which  he  calls  gray  silver 
ore,  as  it  resembles  the  gray  copper  ore 
more  than  it  does  the  white  silver.  This 
gave  him  silver  14.97,  copper  31-36,  anti- 
mony 34.09,  iron  3.3,  sulphur  11.5,  alu- 
mine  0.3.  What  has  frequently  been  call- 
ed gray  silver  ore,  fahlertz,  is  properly  an 
ore  of  copper,  containing  accidentally  a 
small  portion  of  silver  only. 

A  bismuthic  silver  ore  was  found  by 
Selb,  about  fifteen  years  ago,  at  Schap. 
bach,  in  the  Black  Forest.  It  is  chiefly 
disseminated  in  quartz;  and,  analysed  by 
Klaproth,  100  parts  gave  lead  33,  bismuth 
27,  silver  15,  iron  4.3,  copper  0.9,  sulphur 
16  3, 

In  the  duchy  of  Zweybrueeken,  a  na- 
tive amalgam  of  silver  occurs  in  various 
forms.  Some  pure  garnet-like  crystals  of 
it,  analysed  by  Klaproth,  gave  mercuiy 
64,  silver  36. 

<  And  in  Suabia,  an  alloy  of  silver  awd 
antimony  occurs,  one  variety  of  which,  in 
line  grains,  contains  .84  of  silver :  another, 
in  coarse  grains,  .76 :  the  remainder  in 
each  being  antimony. 

The  following  processes,  like  the  others  ex- 
tracted from  Cramer's  Art  of  Assaying. 


ORE 


ORE 


are  valuable  for  the  minute  accuracy  of 
the  instruction  as  to  the  management  <f 
assays  by  the  furnace. 

Process  I. 

To  precipitate  silver  by  means  of  lead  from 
fusible  ores. 

Pound  the  ore  in  a  very  clean  iron  mor- 
tar into  fine  powder :  of  this  weigh  one 
docimnstical  centner  or  quintal,  and  eight 
of  the  like  centners  of  granulated  lead. 

Then  have  at  hand,  a  docimastical  test, 
that  has  never  yet  been  used :  pour  into  it 
about  half  of  the  granulated  lead,  and 
spread  it  with  your  fingers  through  the 
cavity  of  it. 

Put  upon  this  lead  the  pounded  ore ; 
and  then  cover  it  quite  with  the  remain- 
der of  the  granulated  lead. 

Put  the  test,  thus  loaded,  under  the 
muffle  of  an  assay-furnace,  and  in  the  hin- 
der part  of  it:*then  make  your  fire,  and 
increase  it  gradually.  If  you  look  through 
the  holes  of  either  of  the  slides,  you  will 
soon  see,  that  the  pounded  ore  will  be 
raised  out  of  the  melted  lead,  and  swim 
upon  it.  A  little  afterward,  it  will  grow 
clammy,  melt,  and  be  thrown  towards  the 
border  of  the  test :  then  the  surface  of 
the  lead  will  appear  in  the  middle  of  the 
test  like  a  bright  disk,  and  you  will  see  it 
smoke  and  boil :  as  soon  as  you  see  this, 
it  w  ill  be  proper  to  diminish  the  fire  a 
small  matter  for  a  quarter  of  an  hour,  so 
that  the  boiling  of  the  lead  may  almost 
cease.  Then  again  increase  the  fire  to 
such  a  degree,  that  the  whole  mass  may 
be  converted  into  a  thin  fluid,  and  the 
lead  may  be  seen,  as  before,  smoking  and 
boiling  witli  great  violence.  The  surface 
will  then  diminish  by  degrees,  and  be- 
come covered  with  a  mass  of  scoria:.  Fi- 
nally, have  at  hand  an  iron  hook  ready 
heated,  wherewith  the  whole  mass  must 
be  stirred,  especially  toward  the  border ; 
that  in  case  any  small  parcels  of  the  ore, 
not  yet  dissolved,  should  be  adherent 
there,  they  may  be  brought  down,  taking 
great  care  not  to  stir  the  least  particle 
out  of  the  test. 

i\ow,  if  what  is  adherent  to  the  hook 
during  the  stirring,  when  you  raise  it 
above  the  test,  melt  quickly  again,  and 
the  extremity  of  the  hook,  grown  cold,  be 
covered  with  a  thin,  smooth,  shining 
crust ;  it  is  a  sign  that  the  scorification  is 
perfect ;  and  it  will  be  the  more  so,  as  the 
said  crust  adherent  to  the  hook  shall  be 
coloured  equally  on  every  side ;  but  in 
case,  while  the  scoriae  are  stirred,  you 
perceive  any  considerable  clamminess  in 
them,  and  when  they  adhere  in  good 
quantity  to  the  hook,  though  red-hot, 


and  are  unequally  tinged,  and  seem  dusty 
or  rough  with  grains  interspersed  here 
and  there  ;  it  is  a  sign  that  the  ore  is  not 
entirely  vitrefied.  In  this  case,  you  must 
with  a  hammer  strike  off  what"  is  adhe- 
rent to  the  hook,  pulverize  it,  and  with  a 
ladle  put  it  again  into  the  test,  without 
any  loss,  or  mixture  of  any  foreign  body, 
and  continue  the  fire  in  the  same  degree, 
till  the  scoria  has  acquired  its  perfection, 
and  the  above-mentioned  qualities.  This 
once  obtained,  take  the  test  with  a  pair 
of  tongs  out  of  the  fire,  and  pour  the 
lead,  together  with  the  scoria  swimming 
upon  it,  into  a  cone  made  hot  and  rubbed 
with  tallow  Thus  will  the  process  of 
the  first  operation  be  performed,  which 
does  not  commonly,  indeed,  last  above 
three  quarters  of  an  hour. 

With  a  hammer  strike  the  scoriae  off 
from  the  regulus  grown  cold,  and  again 
examine  whether  they  have  the  character- 
istics of  a  perfect  scorification :  if  they 
have,  you  may  thence  conclude  that  the 
silver  has  been  precipitated  out  of  the 
ore  turned  to  scoriae,  and  revived  by  the 
lead. 

When  the  scorification  lasts  longer  than 
we  have  mentioned,  the  lead  at  last  turns  to 
scoriae  or  litharge,  and  the  silver  remains 
at  the  bottom  of  the  vessel ;  but  the  fire 
must  be  moderately  supplied,  and  the  ves- 
sel be  extremely  good,  to  produce  this  ef- 
fect ;  for  they  seldom  resist  the  strength 
of  the  scoria:  long  enough ;  so  that  the 
whole  scorification  may  be  brought  to  an 
end;  which  has  afterward  this  inconve- 
nience, that  the  silver  is  dissipated  by 
grains  in  the  small  hollows  of  the  corrod- 
ed ore,  and  can  hardly  be  well  collected 
again,  when  the  ore  has  but  little  silver 
in  It.  Indeed,  there  is  still  more  time  to 
be  consumed  to  obtain  the  perfect  de- 
struction of  the  lead,  by  means  of  the 
combined  actions  of  the  fire  and  air,  be- 
cause the  scoriae  swimming  at  the  top  re- 
tard it  considerably. 

In  this  process,  the  sulphur  and  the  ar- 
senic of  the  silver  ore,  when  the  ore  is 
broken  small,  and  extended  widely  in  a 
small  quantity,  are  in  part  easily  dissipat- 
ed by  the  fire,  and  in  part  absorbed  by  the 
lead  ;  the  lighter  part  of  which,  swimming 
upon  the  heavier,  becomes  very  clammy, 
by  means  of  the  sulphur  which  is  in  the 
ore  :  but  when  this  is  dissipated,  by  the 
violence  of  the  fire,  it  turns  into  glass  or 
scoriae :  but  when  arsenic  is  predominant 
in  the  ore,  the  plumbeous  part  turns  im- 
mediately, into  a  very  penetrating  and  very 
fusible  glass,  having  a  dissolving  efficacy, 
unless  the  arsenic  lies  hidden,  in  a  white 
pyrite  or  cobalt.  For  this  reason,  the  fix- 
ed part  of  the  ore,  which  is  no  silver,  is. 


ORE 


OKE 


dissolved  by  the  glass,  melts,  and  assumes 
the  form  of  scoria:.  The  unmetallic  earths 
and  the  pure  copper  of  lead-ores,  which 
adheres  to  it,  are  of  this  kind.  The  silver 
then  remains  immutable ;  and  being  freed 
from  these  heterogeneous  bodies,  which 
are  partly  dissipated,  and  partly  melted, 
it  is  precipitated  and  received  by  the  re- 
maining- lead.  Hence  this  process  is 
completed  by  three  distinct  operations  ; 
viz,. 

1.  By  roasting. 

2.  By  scorification. 

3.  By  the  melting  precipitation  of  the 
silver,  which  is  the  result  of  the  two  for- 
mer operations. 

The  ore  must  be  pulverised  very  fine, 
in  order  to  increase  the  surface,  that  the 
dissipation  of  the  volatiles,  and  the  disso- 
lution by  litharge,  may  be  sooner  effect- 
ed. t  This  pulverizing  must  be  done,  be- 
fore the  ore  is  weighed,  because  there  is 
always  some  part  of  the  ore,  adherent  to 
the  mortar  or  iron  plate,  on  which  it  is 
made  fine  ;  which  part  being  lost,  the  ope- 
ration is  not  exact.  Erker  was  in  the 
right,  when  he  prescribed  eight  centners 
of  lead,  for  the  subduing  ot  fusible  ores. 

Nevertheless  it  must  be  owned,  that 
this  quantity  is  superfluous,  in  some  cases. 
However,  as  the  flexibility  of  the  silver 
ore,  depends  on  the  absence  of  stones, 
pyrites,  &c,  it  is  easy  to  see,  that  there 
are  an  infinite  number,  of  degrees  of  fluxi- 
bility,  which  it  would  be  needless  to  de- 
termine by  the  bare  sight.  Besides,  a  lit- 
tle more  lead  does  not  render  the  process 
imperfect ;  on  the  contrary,  if  you  use  too 
small  a  quantity  of  lead,  the  scorification 
is  never  completely  accomplished.  In- 
deed there  are  a  great  many  ores,  that 
destroy  a  considerable  quantity  of  lead  : 
such  are  the  red  silver  ore,  and  that  in 
which  there  is  a  great  deal  of  the  steel- 
grained  lead  ore.  If  the  fire  must  be  some- 
times diminished,  in  the  middle  of  the  pro- 
cess, it  is  in  order  to  hinder  the  too  much 
attenuated  litharge,  which  is  continually 
generated  out  of  the  lead,  from  penetrat- 
ing the  pores  of  the  test,  and  from  corrod- 
ing it ;  which  is  easily  done,  when  the  fire 
is  over  strong  ;  for  then  the  surface  of  the 
vessel,  which  is  contiguous  to  the  lead, 
contracts  cavities,  or  being  totally  consum- 
ed by  small  holes,  lets  the  metal  flow  out 
of  it.  The  vessels  that  are  most  subject 
to  this  inconvenience  are  those,  in  the  ma- 
terials of  which  lime,  plaster,  and  chalk, 
are  mixed.  Nay,  these  bodies,  which  are 
naturally  refractory,  being  eroded  during 
their  scorification,  at  the  same  time  com- 
municate a  great  clamminess  to  the  sco- 
ria; so  that  a  great  quantity  of  the  mass, 
remains  adherent  to  the  test,  in  the  form 

VOL.  II. 


of  protuberances,  when  it  is  poured  out  . 
and  by  this  means  a  great  many  grains  of 
the  regulus  are  detained. 

Process  II. 

The  button  obtained  by  the  preceding 
process,  contains  all  the  silver  of  the  ore, 
and  the  unscorified  part  of  the  lead.  The 
silver  may  be  afterwards  separated  from 
the  lead,  and  obtained  pure,  by  cupella- 
tion. 

Process  III. 

If  the  silver  ore  cannot  be  ivashed  clean,  of> 
if  it  be  rendered  refractory  by  a  mixture 
of  unmetallic  earths  and  stones,  the  sco- 
r if  cation  of  these  earthy  matters,  fre- 
quently cannot  be  completed  by  Process 
I :  Cramer  therefore  directs,  that  such 
ores,  shall  be  treated  in  the  following 
manner. 

Bruise  the  ore  into  an  impalpable  pow- 
der, by  grinding  in  a  mortar;  to  a  docimas- 
tical  centner  of  it,  add  a  like  quantity  of 
glass  of  lead,  finely  pulverized  s  lor  the 
more  exactly,  these  two  are  mixed  toge- 
ther, the  more  easily  the  scorification  after- 
ward succeeds.  Put  this  mixture,  toge- 
ther with  12  centners  of  lead,  into  the  test, 
according  to  Process  I ;  then  put  the  test 
under  the  muffle. 

Make  first  under  it  a  strong  fire,  till  the 
lead  boils  very  well  ;  when  this  takes 
place,  diminish  the  violence  of  the  heat, 
as  was  directed  in  Process  I,  but  keep  it 
thus  diminished  a  little  longer :  then  final- 
ly again  increase  the  fire  to  such  a  degree, 
till  you  perceive  the  signs  of  a  perfect 
scorification,  and  fusion.  Now  this  pro- 
cess, lasts  a  little  longer  than  the  tore- 
going,  and  requires  a  greater  fire  toward 
the  end. 

It  sometimes  happens,  that  a  very  re- 
fractory ore  cannot  be  dissolved  by  li- 
tharge, and  that  a  mass,  which  has  the 
clamminess  of  pitch,  swims  upon  the  me- 
tal, and  upon  the  scorix  themselves,  which 
are  already  subdued  to  part:  when  this 
takes  place,  shut  the  vents  of  the  furnace 
to  diminish  the  fire;  then  gently  touch 
this  refractory  body,  with  a  small  iron 
hook,  to  which  it  will  immediately  stick ; 
take  it  off  softly,  not  to  lose  any  thing ; 
pound  it  into  a  fine  powder,  adding  a  lit- 
tle glass  of  lead,  and  put  it  again  into  the 
test ;  then  continue  the  scorification,  till 
it  is  brought  to  its  perfection.  But  you 
must  always  examine  the  scoria  of  your 
refractory  ore,  to  see  whether  there  may 
not  be  some  grains  of  metal  dispersed  in 
it :  for  sometimes,  the  sconx  that  grow 
clammy  retain  something  of  the  metal ; 

e  e 


ORE 


ORE 


which  if  you  suspect,  pound  the  scoria 
into  a  fine  dust,  and  thus  the  grains  of 
metal  will  appear,  if  there  be  any  left,  be- 
cause they  can  never  be  pounded  fine.  The 
silver  is  separated  by  cupelling,  as  in  Pro- 
cess I. 

All  earths  and  stones  are  refractory  in 
the  fire ;  tor  although  some  of  them  melt 
naturally  in  the  fire,  as  is  the  case  with 
those  that  are  verifiable ;  yet  all  the  others, 
a  very  few  excepted,  melt  with  much 
greater  difficulty  than  metals,  and  never 
become  so  thin  in  the  fusion  as  is  requi- 
site for  the  sufficient  precipitation  of  a 
precious  metal.  But  litharge  does  not  con- 
veniently dissolve  these  refractory  mat- 
ters, by  the  help  of  fire  alone,  without 
mechanical  mixture  ;  for  the  very  moment 
the  litharge  penetrates,  through  the  inter- 
stices of  the  refractory  ore,  and  begins  to 
dissolve  it,  a  tenacious  mass  is  produced, 
which  hardly  admits  any  farther  dilution, 
by  the  litharge.  You  may  plainly  perceive 
this,  when  you  make  coloured  glasses, 
with  metallic  oxides ;  for,  if  you  pour  care- 
lessly upon  tbem,  an  oxide  that  gives  a 
colour,  you  will  never  cause  them,  to  be 
equally  tinged  throughout,  even  though 
you  should  torture  them,  for  whole  days 
together,  in  a  strong  fire.  Indeed,  glass 
already  made  can  never  be  diluted,  by  only 
pouring  salts  and  litharge  upon  it.  Hence, 
you  must  use  the  artifice  of  glass-makers, 
who,  in  the  making  of  the  most  perfect 
glasses,  take  great  care  to  mix  their  ingre- 
dients well,  either  before  they  put  them 
into  the  fire,  or  at  least  during  the  fusion 
itself,  which  is  done  here  by  pounding 
glass  of  lead,  mixed  with  the  ore :  but  if 
you  think,  that  your  glass  of  lead  is  not 
sufficiently  fusible,  you  may  add  to  it  li- 
tharge, melted  first,  and  then  pounded 
into  a  fine  powder. 

As  this  scorification  requires  a  longer 
and  a  greater  fire  than  the  foregoing,  and 
as  a  greater  quantity  of  litharge,  is  beside 
this  requisite  to  subdue  the  refractory 
scoria  ♦  it  is  easy  to  see,  why  a  much 
greater  quantity  of  lead  must  be  used  here, 
than  in  Process  I ;  and  although  less  lead 
is  often  sufficient,  it  is  nevertheless  pro- 
per, always  to  use  the  greatest  quantity 
that  can  be  requisite  ;  lest,  for  instance, 
it  should  be  necessary  to  try  so  many 
times,  the  lead  alone,  to  make  it  evident 
how  much  silver  the  lead,  when  alone, 
leaves  in  the  cupel.  Nor  is  there  any  oc- 
casion to  fear,  lest  any  thing  of  the  silver, 
be  taken  away  by  the  lead,  provided  the 
cupels  be  good,  and  the  cupelling  duly 
put  in  execution  :  for  you  can  hardly  col- 
lect a  ponderable  quantity  of  silver,  out 
of  the  fumes  of  the  lead,  which  rise  dur- 
ing the  cupelling,  as  well  as  out  of  the 


litharge,  that  is  withdrawn  into  the  cu> 
pel. 

Process  IV. 

If  the  ore  be  rendered  rifractory  by  pyrites, 
Cramer  directs,  that  the  silver  should  be 
precipitated  by  lead,  in  the following  man- 
ner. 

Break  your  ore  into  a  rough  powder, 
and  put  a  centner  of  it  into  the  test  in  the 
manner  of  a  tile  ;  put  it  under  the  muffle 
hardly  red-hot :  increase  the  fire  by  de- 
grees. There  will  always  be  a  crackling ; 
which  being  ended,  take  away  the  upper 
test ;  for  when  the  vessels  have  been  red- 
hot  about  one  minute,  the  ore  ceases  to 
split.  Leave  the  ore  under  the  muffle, 
till  the  arsenic  and  the  sulphur,  are  for  the 
most  part  evaporated ;  winch  you  will 
know  from  the  cessation  of  the  visible 
smoke,  of  the  smell  of  garlic,  or  the  acid  ; 
then  take  away  the  test,  and  leave  it  in  a 
place  not  too  cold,  that  it  may  cool  of 
itself. 

Pour  out,  without  any  dissipation,  the 
roasted  ore,  and  with  a  knife  take  away 
what  is  adherent  to  the  vessel ;  pound  it 
together  with  an  equal  weight  of  glass 
of  lead  ;  and  lastly,  scorify  the  whole  col- 
lected ore,  in  the  same  test,  in  which  the 
testing  was  made,  unless  it  had  contracted 
chinks,  as  was  described  in  Process  III. 

Remarks.  Yellow  pyritous  ores  contain 
a  very  great  quantity  of  sulphur,  even 
greater  than  is  necessary  to  saturate  the 
metal  that  lies  concealed  in  them.  For 
which  reason,  this  superfluous  sulphur 
dissipates  in  a  middling  fire  :  but  if  it  had 
been  mixed  with  lead,  it  would  have  ren- 
dered it  refractory,  nor  could  it  afterward 
be  dissipated  from  it,  without  a  consider- 
able destruction  of  the  lead.    The  white 
J  arsenical  pyrites,  turn  also  a  great  quan- 
j  tity  of  lead  into  glass,  on  account  of  the 
;  abundance  of  the  arsenic  they  contain. 
'  In  consequence  of  this,  these  ores  must  be 
previously  roasted,  that  the  sulphur  and 
i  arsenic  may  be  dissipated     Nor  is  there 
:  any  occasion  to  fear,  lest  any  part  of  the 
silver,  be  carried  away  with  the  arsenic  ; 
'  for  when  arsenic  is  separated  from  any 
i  fixed  body,  by  a  certain  degree  of  fire,  it 
carries  nothing  of  that  body  away  with  it. 

Process  V. 

Silver  may  be  precipitated  from  its  ore  by 
cupellation  only,  in  the  following  process, 
given  by  Cramer. 

Tound  one  centner  of  ore  roasted  in  the 
'  manner  directed  in  the  last  process  ;  beat 
j  it  to  a  very  subtile  powder ;  and  if  it  melt 
|  with  difficulty  on  the  fire,  grind  it  toge- 


ORE 


ORE 


ther  with  one  centner  of  litharge,  which 
is  not  necessary,  when  the  ore  melts  easily; 
then  divide  the  mixture,  or  the  powder 
of  the  ore  alone,  into  five  or  six  parts,  and 
wrap  up  every  one  of  them  severally  in 
such  bits  of  paper,  as  can  contain  no  more 
than  this  small  portion. 

Put  a  very  large  cupel  under  the  muf- 
fle ;  roast  it  well  first,  and  then  put  into  it 
16  centners  of  lead  ;  when  the  lead  be- 
gins to  smoke  and  boil,  put  upon  it  one 
of  these  portions,  wit  h  the  small  paper  it 
was  wrapped  up  in,  and  diminish  the  fire 
immediately,  in  the  same  manner,  as  if 
you  would  make  a  scorification  in  a  test, 
but  in  a  less  time.  The  small  paper,  winch 
turns  presently  to  ashes,  goes  off  of  itself, 
and  does  not  sensibly  increase  the  mass 
of  the  scorias.  The  ore  proceeding  from 
this  is  cast  on  the  border,  and  very  soon 
turns  to  scoriae.  Increase  the  fire  again 
immediately,  and  at  the  same  time  put 
another  portion  of  the  ore  into  the  cupel. 
The  same  effects  will  then  be  produced. 
Continue  your  operations  in  the  same 
manner,  till  all  the  portions  are  thrown 
in  and  consumed  in  the  lead.  Lastly,  de- 
stroy the  remaining  lead  with  a  stronger 
fire. 

The  silver  that  was  in  the  ore,  and  in 
the  lead  will  remain  in  the  cupel.  If  you 
deduct  from  it  the  bead,  proceeding  from 
the  lead,  you  will  have  the  weight  of  the 
silver  contained  in  the  ore.  If  the  ore 
employed  were  easy  to  be  melted,  all  the 
scoria  vanishes  ;  but  if  it  were  refractory, 
or  not  fusible,  all  the  scoria  does  not  al- 
ways pass  away,  but  there  remains  some- 
thing of  it  occasionally,  in  the  form  of 
dust.  A  great  many  ores  and  metals  may 
be  tried  this  way,  except  such  only  as 
split  and  corrode  the  cupels.  There  are 
likewise  some  of  them,  which  must  be 
previously  prepared,  in  the  same  manner 
as  is  required  to  render  them  fit  for  going 
through  a  scorification.  See  the  preced- 
ing Processes. 

Remarks.  The  ore  thrown  at  several 
times  upon  lead  boiling-  in  a  cupel,  may  be 
dissolved  without  the  foregoing  scorifica- 
tion :  but  this  is  very  far  from  having  an 
equal  success  with  ail  kinds  of  ores  ;  for 
there  are  ores  and  metals,  which  resist 
very  much  the  dissolution  by  litharge  ; 
and  which  being  on  this  account  thrown 
on  the  border,  are  not  sufficiently  dissolv- 
ed ;  because  the  litharge  soon  steals  away 
into  the  cupel.  Nevertheless  there  are 
some  others,  which  vanish  entirely  by  this 
method,  except  the  silver  and  gold,  that 
were  contained  in  them.  A  previous  roast- 
ing is  necessary ;  first,  for  the  reasons 
mentioned,  and  then,  because  the  ore 
thrown  upon  boiling  lead,  should  not 


crackle  and  leap  out  ;  for,  having  once 
passed  the  fire,  it  bears  the  most  sudden 
heat. 

Process  VI. 

Silver  may  be  precipitated  out  of  the  same 
bodies  as  were  mentioned  in  the  foregoing 
processes,  by  scorification  in  a  crucible. 
The  body  out  of  which  you  intend  to 
precipitate  silver,  must  be  previously  pre- 
pared for  a  scorification,  by  pounding  and 
roasting,  as  mentioned  in  the  former  pro- 
cesses. Then  in  the  same  manner,  and 
with  the  same  quantity  of  lead,  put  it  into 
a  crucible,  which  is  found  on  strict  exa- 
mination to  be  entire,  solid,  not  speckled 
with  black  spots,  like  the  scoria  of  iron, 
especially  at  its  inferior  parts,  and  capa- 
ble of  containing  three  times  as  much. 
Add  besides  glass-gall  and  common  salt, 
both  very  dry,  and  in  sufficient  quantities, 
that,  when  the  whole  is  melted,  the  salts 
may  swim  at  the  top,  at  the  height  of 
about  half  an  inch. 

Put  the  crucible  thus  loaded  into  a  wind- 
furnace  ;  shut  it  close  with  a  tile ;  put 
coals  round  it,  but  not  higher  than  the 
upper  boarder  of  the  crucible.  Then  light 
them  with  burning  coals,  and  increase  the 
fire  till  the  whole  melts  very  thin,  which 
will  be  done  by  a  middling  fire,  maintain- 
ed always  equal,  and  never  greater ;  leave 
it  thus  for  about  one  quarter  of  an  hour, 
that  the  scorification  may  be  perfectly 
made.  Take  off  the  tile,  and  stir  the 
mass  with  an  iron  wire,  and  a  little  after 
pour  it  out  into  the  mould.  When  the 
metal  is  cleared  from  scoriae,  try  it  in  a 
test  by  cupelling  it. 

Remarks.  The  scorification  of  any  ore 
whatever,  or  of  any  body  fetched  out  of 
ores,  may  indeed  be  made  by  this  appa- 
ratus, as  well  as  in  a  test  under  a  muffle: 
but  it  serves  chiefly  to  the  end,  that  a 
greater  quantity  of  metal,  may  be  melted 
from  it  with  profit.  P'or  you  may  put 
many  common  pounds  of  it,  at  one  single 
time  into  the  crucible  ;  but  then  you  need 
not  observe  the  proportion  of  lead  in  the 
foregoing  process ;  indeed,  a  quantity  of 
lead,  two  or  three  times  less  is  sufficient, 
according  to  the  different  qualities  of  the 
object.  But  the  mass  will  certainly  be 
spilt,  unless  you  choose  a  very  good  cru- 
cible ;  for  there  is  no  vessel  charged  with 
litharge,  that  can  bear  a  strong  fire  hav- 
ing a  draught  of  wind,  without  giving  way 
through  it  to  the  litharge. 

You  add  glass-gall  and  common  salt, 
that  they  may  forward  the  scorification, 
by  swimming  at  top ;  for  the  refractory 
scoria  rejected  by  the  litharge,  and  adher- 
ing between  this  and  the  salts  that  swim 


ORE 


ORE 


at  top,  is  soon  brought  to  a  flux,  and  the 
precipitation  of  the  silver  is  thereby  acce- 
lerated. They  also  hinder  a  small  burn- 
ing  coal,  fallen  into  the  crucible,  from  set- 
ting- the  litharge  a-boiling-,  which  troubles 
the  operation ;  for  the  litharge,  or  glass 
of  lead,  especially  that  which  is  made  with- 
out any  addition,  as  soon  as  the  carbon 
enters  into  it,  rises  into  a  foamy  mass,  con- 
sisting of  a  multitude  of  small  bubbles, 
very  difficult  to  be  confined,  unless  the 
carbon  be  entirely  consumed,  and  the  li- 
tharge reduced  to  lead,  which  sometimes 
rises  above  the  border  of  the  vessel. 

The  following  is  given  by  J[fr.  Sage,  as  the 
best  method  of  assaying  ores  of  silver. 
Melt  a  quintal  of  the  roasted  ore  with 
as  much  litharge,  and  three  quintals  of 
common  carbonat  of  potash,  in  a  crucible, 
the  bottom  of  which  is  lined  with  24  or 
30  grains  of  charcoal,  softened  with  a  lit- 
tle oil,  so  that  the  paste  may  be  applied  to 
the  bottom,  and  half  way  up  the  side  by 
the  finger.  Put  on  a  cover,  but  without 
luting  it.  Place  two  such  crucibles  side 
by  side  in  a  common  furnace,  and  cover 
them  with  charcoal.  The  bellows  are  not 
necessary.  When  the  mixtures  enter  into 
fusion,  which  will  readily  be  perceived 
by  the  ear,  ptish  the  charcoal  aside,  so  that 
you  may  be  able  to  take  off  the  lids,  and 
see  what  is  going  on.  If  the  effervescence 
raise  the  contents  above  the  middle  of  the 
crucible,  remove  the  lids,when  the  weight 
of  the  air  will  check  the  swell,  and  pre- 
vent it  from  running  over.  As  soon  as  all 
is  quiet,  put  on  the  lids  again,  cover  up 
the  crucibles  with  charcoal,  and  let  them 
stand  till  they  are  cold  If  the  assays  have 
been  well  fused,  the  leads  obtained  will 
not  differ  in  weight  two  grains.  Subject 
them  to  cupellation,  and  you  will  obtain 
buttons,  which  ought  not  to  differ  a  six- 
teenth of  a  grain.  A  sixteenth  of  a  grain 
represents  an  ounce  in  a  hundred  pounds  : 
but  if  the  ore  be  so  poor  as  to  yield  less 
than  an  ounce,  as  is  the  case  with  most  of 
the  mines,  at  present  worked  in  America, 
the  assay  should  be  made  witii  400  grains 
at  least. 

Native  metallic  silver  maybe  separated 
from  the  stones  and  earths  with  which  it 
is  intermixed  by  amalgamation  with  mer- 
cyry,  which  operation  is  to  be  performed 
in  the  same  manner  as  in  the  separation  of 
native  gold. 

Ores  of  Tantalium. 
Of  these  only  two  have  yet  been  found, 
in  both  of  which  the  metal  is  in  the  state 
of  oxide.  One  of  them  was  mistaken  for 
an  ore  of  tin,  till  it  was  analysed  by  Ecke- 
berg. 


Ores  qf  Tellurium. 
The  ores  of  this  lately  discovered  metal 
have  yet  been  found  only  in  the  gold 
mines  of  Transylvania.  In  all  of  them 
the  metal  is  in  the  state  of  an  alloy,  being 
combined  with  gold  in  every  species, 
though  but  with  a  very  minute  portion  in 
the  native  tellurium,  tormerly  known  by 
the  name  of  aurum  partidoxicum,  which 
contains  92  55  of  tellurium,  and  7- 20  of 
iron,  in  the  hundred  parts.  In  the  gra- 
phic gold  ore,  yellow  gold  ore,  and  folia- 
ted or  black  ore,  it  is  united  with  silver 
likewise.  In  the  second  and  third  of  these 
there  is  a  considerable  portion  of  lead,  and 
some  sulphur  :  and  the  last  contains  a  lit- 
tle copper  also. 

Ores  of  Tin. 

The  existence  of  native  tin  was  long  a 
matter  of  doubt  among  mineralogists.  It 
has,  nevertheless,  been  undoubtedly  found 
in  various  places.  Magellan,  among  other 
specimens,  mentions,  1.  Malleable  tin  in  a 
granular  form,  and  also  foliaceous,  bedded 
in  a  white  hard  matter,  resembling  quartz, 
but  which,  on  proper  examination,  proved 
to  be  arsenic  ;  a  circumstance  that  evinces 
its  befog  native  tin,  because  the  arsenic 
could  not  have  retained  this  form,  if  the  tin 
had  undergone  the  fusing  heat.  Jt  appear- 
ed like  a  thick  jigged  or  scolloped  lace  or 
edging,  and  was  found  at  St.Austel  in  Corn- 
wall, England.  2.  In  the  form  of  cr\ stal- 
line  metallic  laminae, or  flat  crystals,  rising 
side  by  side  out  of  an  edging,  which  shone 
like  melted  tin.  They  were  nearly  as  thin 
as  the  leaves  of  talc,  intersecting  each 
other  in  various  directions,  with  some  ca- 
vities between  them,  within  which  appear- 
ed many  specks  and  granules  of  tin  that 
could  easily  be  cut  with  a  knife  ;  this  also 
came  from  Cornwall.  3-  In  a  massy  form, 
more  than  an  inch  thick  in  some  places, 
and  enclosed  in  a  stone  resembling  quartz, 
which  was  taken  to  be  a  hard  crust  of 
crystallized  arsenic. 

All  the  ores  of  tin  hitherto  found,  ex- 
cept the  sulphuret  from  Huel  or  "W  heal 
Rock,  St  Agnes,  Cornwall,  are  in  the  ox- 
ided  state.  They  are  remarkable  for  their 
great  weight,  which  is  between  5-8  and 
6.97,  according  to  Klaproth. 

The  common  ore,  called  tin-stone,  has 
a  vitrified  appearance,  resembling  a  gar- 
net of  a  blackish-brown  colour,  but  much 
heavier.  Its  surface  is  shining,  sometimes 
striated,  and  its  fracture  lamellar;  soft 
enough  to  be  cut  or  scraped  with  a  knife, 
and  affording  a  pale  red  powder.  Some 
authors  assert,  that  it  contains  arsenic, 
but  Kirwan  positively  denies  the  existence 
of  arsenic  as  a  mineralizer  of  tin.  The 
;  Germans  call  the  irregular  compact  tin 


ORE 


ORE 


ore  by  the  name  of  zinnstein;  but  the 
crystallized  tin-stones  are  called  zinngrau- 
pen,  H*  the  crystals  be  distinct  and  some- 
what  large.  The  zinnzwitter  ores,  in 
which  the  crystals  are  small,  and  not  so 
distinct,  resemble  small  grains,  scattered 
through  a  compact  raw  tin-stone,  or  a 
stone  of  any  other  kind. 

The  common  matrix  of  tin  in  the  Cor- 
nish mines  is  the  killas,  and  the  grow  an. 
This  consists  of  white  clay,  mixed  with 
mica  and  quartz,  without  any  particular 
texture;  which,  when  lamellar  and  hard, 
is  called  gneiss  by  the  Germans,  and  is 
nothing  else  but  decayed  granite,  in  which 
the  felt  spar  has  been  broken  down  to 
clay. 

The  zinngraupen,  or  brown  crystallized 
tin -stone,  from  Cornwall,  consists  of  quad- 
rangular prisms,  or  double  quadrangular 
pyramids,  joined  by  their  bases,  so  that 
these  crystals  are  octoedral ;  these  are 
found  at  Trwaunance  and  Soil-hole,  in  the 
parish  of  St-  Agnes.  Similar  prismatic 
crystals,  but  of  as  small  a  size  as  a  hair, 
are  found  in  tin-stone  upon  killas,  at  Pol- 
gooth,  one  of  the  richest  tin  mines,  which 
produces  sometimes  a  clear  profit  from 
1000  to  1200/.  sterling  per  month. 

The  stream -tin  is  collected  in  the  val- 
lies  of  the  tin  mountains  in  Cornwall,  and 
yields  a  considerable  quantity  of  this  me- 
tal. The  soil  is  dug  several  feet  deep,  and 
washed  by  water  going  over  it,  till  the 
heavier  particles  of  the  ore  remain  at  the 
bottom.  These  are  nothing  else  but  the 
abrasions  of  the  tin  ores  over  the  moun- 
tains, which  are  rolled  down  the  declivi- 
ties of  the  hills  to  lower  grounds. 

The  stream-tin  from  Fensagillis  is  re- 
markable on  account  of  the  native  gold 
now  and  then  met  with  in  it ;  and  found, 
though  very  rarely,  in  pieces  of  the  value 
of  two  or  three  pounds  sterling.  It  prin- 
cipally consists  of  round,  oval,  and  some- 
what smooth  pieces,  from  the  size  of  a 
bean  to  that  of  a  pea,  and  less,  the  po- 
lished surfaces  of  which  show  a  variety  of 
reddish,  gray,  light-brown,  and  dark  yel- 
low colours. 

The  wood-tin  ore  looks  like  hematites, 
and  is  found  in  the  parishes  of  St.  Co- 
lumb,  Roach,  and  St.  Denis.  This  is  with- 
out any  crystallized  form,  and  has  a  very 
inconsiderable  quantity  of  iron  with  it. 

Another  wood-like "  tin  ore,  described 
by  professor  Brunnich,  shows  various  fine 
fibres  converging  to  different  centres,  like 
the  radiated  zeolyte ;  but  is  so  compact 
and  hard,  as  to  strike  fire  with  steel.  Its 
specific  gravity,  at  45°  of  Fahrenheit,  is 
5.80,  and  even  6.45.  It  contains  some  ar- 
senic and  a  considerable  proportion  of 
iron ;  and  gives  sometimes  63.5  per  cent. 


of  tin.  It  is  very  scarce,  and  found  only 
in  small  pieces. 

The  tin  spar,  or  white  tin  ore,  is  gene- 
rally of  a  whitish  or  gray  colour;  some- 
times it  is  yellowish,  semitransparent,  and 
crystallized,  either  of  a  pyramidal  form, 
or  irregular.  It  resembles  a  calcareous, 
or  rather  ponderous  Spar,  but  is  easily 
known  by  its  great  weight,  and  shining 
greasy  appearance.  Its  fracture  also  is 
vitreous.  It  was  formerly  thought  to  con- 
tain arsenic,  but  Margraaf  found  it  to  be 
the  purest  of  all  tin  ores ;  though  it  is 
said  to  contain  sometimes  a  mixture  of 
calcareous  earth.  Its  specific  gravity  is 
=  6.007. 

Tin  grains  are  of  a  spherical  polygonal 
figure,  like  the  garnets;  but  seem  more 
unctuous  on  their  surface.  It  is  found 
either  in  large  or  small  grains. 

Bergman  received  a  specimen  of  native 
aurum  musivum  from  Nerschinskoi  in  Si- 
beria. It  resembled  the  artificial  aurum 
musivum  externally,  or  rather  the  aurum 
musivum  formed  a  crust  environing  a  nu- 
cleus radiated  in  its  fracture,  and  resem- 
bling a  white  metal.  It  yielded  to  the 
knife,  and  the  place  of  section  exhibited 
a  variable  colour.  Its  powder  was  black. 
By  the  analysis,  it  proved  to  consist  of  tin 
mineralized  by  sulphur,  with  a  very  small 
portion  of  copper.  In  the  Journal  de  Phy- 
sique for  1783,  it  is  said,  that  the  speci- 
men was  too  small  to  admit  of  a  determi- 
nation of  the  quantities  in  the  large  way : 
but  in  the  preface  to  the  Sciagraphia  it  is 
said,  that  the  native  aurum  musivum  con- 
tained forty  pai'ts  of  sulphur  to  one  of  tin  ; 
and  the  other  mineral,  which  resembled 
antimony,  contained  one  fifth  part  of  sul- 
phur only. 

At  Huel  Rock,  in  St.  Agnes,  in  Corn- 
wall, there  has  been  found  a  metallic  vein 
nine  feet  wide,  at  twenty  yards  beneath 
the  surface.  Raspe  was  the  first  who  dis- 
covered this  to  be  a  sulphuret  of  tin  :  it  is 
very  compact,  of  a  blueish  white  colour, 
approaching  to  gray  steel,  and  similar  to 
the  colour  of  gray  copper  ore  :  it  is  lamel- 
lar in  its  texture,  and  very  brittle.  It  con- 
sists of  sulphur,  tin,  copper  and  some 
iron.  Raspe  proposes  to  call  it  bell-metal 
ore. 

According  to  Klaproth's  analysis  of  this 
ore,  100  parts  contain  25  of  pure  sulphur, 
34  of  tin,  36  of  copper,  two  of  iron,  and 
three  grains  of  the  stony  matrix.  A  faint 
smell  of  arsenic  was  perceptible  in  roast- 
ing it.  The  darker  varieties,  however,  are 
much  poorer  in  tin,  and  contain  more 
iron. 

Bergman's  method  of  assaying  tin  ores 
in  the  humid  way  is  too  commonly  inef- 
fectual.   Klapvoth  gives  the  following 


GUIS 


ORE 


mode.  Mix  the  ore,  in  fine  powder,  with 
a  lixivium  containing  six  times  its  weight 
of  caustic  potash ;  evaporate  to  dryness, 
in  a  silver  vessel,  on  a  sand  heat ;  and  then 
keep  in  a  state  of  moderate  ignition  for 
half  an  hour.  Dilute  the  mass,  while  yet 
warm,  with  boiling  water,  and  filter.  Let 
the  residuum  be  again  ignited  with  six 
times  its  weight  of  potash,  and  dissolve 
in  boiling  water,  as  before.  Mix  the  so- 
lutions, and  add  muriatic  acid,  till  the  pre- 
cipitate, which  falls  down,  is  dissolved  by 
its  excess.  Separate  the  tin  from  the  acid 
by  carbonat  of  soda ;  wash  the  precipi- 
tate; dry  it;  and  re-dissolve  it  in  muria- 
tic acid  by  a  gentle  heat  Into  the  colour- 
less solution,  diluted  with  two  or  three 
parts  of  water,  put  a  stick  of  zinc,  and  in 
a  few  days  the  whole  of  the  tin  will  gather 
round  it  in  dendritic  laminae.  The  resi- 
duum left  after  the  second  solution  is  to 
be  treated  with  muriatic  acid,  and  what 
tin  is  in  it  precipitated  by  zinc  in  the  same 
manner.  If  it  contain  any  i»on,  this  may 
now  be  precipitated  by  prussiat  of  potash. 

The  sulphuret  requires  to  be  treated 
somewhat  differently.  To  one  part  of  the 
powdered  ore  add  four  of  muriatic,  and 
two  of  nitric  acid,  and  after  they  have 
stood  together  24  hours,  digest  for  some 
time  in  a  gentle  sand  heat ;  then  dilute 
with  a  little  water,  and  filter.  Let  the 
sulphur  of  the  residuum  be  burned  off  on 
a  test,  and  treat  what  remains  with  fresh 
nitro-muriatic  acid.  The  part  not  soluble 
being  ignited  with  a  little  wax,  the  iron 
will  be  reduced,  and  the  remainder  is  si- 
lex  from  the  matrix.  The  solutions  are 
to  be  precipitated  with  carbonat  of  pot- 
ash ;  the  precipitate  redissolved  in  muria- 
tic acid  diluted  with  three  parts  of  water ; 
and  a  stick  of  pure  tin  immersed  in  this 
solution.  The  copper  will  be  deposited 
on  the  tin,  and  leave  the  solution  colour- 
less. The  copper  being  dissolved  by 
brisk  digestion  in  nitric  acid,  if  any  tin  be 
mixed  with  it,  this  will  fall  down  in  the 
state  of  white  oxide.  The  tin  may  be  se- 
parated by  zinc,  as  in  the  preceding  in- 
stance ;  and  what  was  dissolved  from  the 
stick  used  in  precipitating  the  copper, 
must  be  deducted  from  its  weight. 

In  the  dry  way,  these  ores,  after  pulve- 
rization and  separation  of  the  stony  mat- 
ter by  washing,  are  to  be  melted  with  a 
mixture  of  double  their  weight  of  a  flux, 
consisting  of  equal  parts  of  pitch  and  cal- 
cined borax,  in  a  crucible  lined  with  char- 
coal, and  to  which  a  cover  is  luted  ;  fusion 
should  be  speedily  procured 

Bergman  recommends  a  mixture  of  one 
part  of  the  ore  with  two  of  tartar,  one  of 
black  flux,  and  half  a  part  of  resin  :  this 
is  to  be  divided  into  three  parts,  and  each 


successively  projected  into  a  crucible  heat- 
ed white,  and  immediately  covered  after 
the  foregoing  portion  ceases  to  flame ;  the 
whole  operation  takes  up  but  7  minutes, 
or  less. 

Previous  to  smelting  in  the  large  way, 
the  impure  ores  of  tin  must  be  cleansed  as 
much  as  is  possible  from  all  heteroge- 
neous matters.  This  cleansing  is  more 
necessary  in  ores  of  tin  than  of  any  other 
metal,  because  in  the  smelting  of  tin  ores 
a  less  intense  heat  must  be  given,  than  is 
sufficient  for  the  scorification  of  earthy 
matters,  lest  the  tin  be  oxided.  Tin  ores 
previously  bruised,  may  be  cleansed  by 
washing,  for  which  operation  their  treat 
weight  and  hardness  render  them  well 
adapted.  If  they  be  intermixed  with  very 
hard  stones,  or  ferruginous  ores,  a  slight 
roasting  will  render  these  impure  matters 
more  friable,  and,  consequently,  fitter  to 
be  separated  from  the  tin  ores.  Some- 
times these  operations,  the  roasting,  con- 
tusion, and  lotion,  must  be  repeated.  By 
roasting,  the  ferruginous  particles  are  so 
far  revived,  that  they  may  be  separated 
by  magnets. 

The  ore,  thus  cleansed  from  adhering 
heterogeneous  matters,  is  to  be  roasted 
in  an  oven,  or  reverberatory  furnace,  with 
a  fire  rather  intense  than  long  continued, 
during  which  it  must  be  frequently  stir- 
red to  prevent  its  fusion.  By  this  opera- 
tion the  arsenic  is  expelled,  and  in  some 
works  is  collected  in  chambers  built  pur- 
posely above  the  oxiding  furnace. 

Lastly,  the  ore  cleansed  and  washed  is 
to  be  fused,  and  reduced  to  a  metallic 
state  In  this  fusion,  attention  must  be 
given  to  the  following  particulars : 

1.  No  more  heat  is  to  be  applied  than 
is  sufficient  for  the  reduction  of  the  ore, 
because  this  metal  is  fusible  with  very 
little  heat,  and  is  very  easily  oxidable. 

2.  To  prevent  this  oxidation  of  the  re- 
duced metal,  a  larger  quantity  of  char- 
coal is  used  in  this  than  in  the  other  fu- 
sion. 

3.  The  scoria  must  be  frequently  re- 
moved, lest  some  of  the  tin  should  be  in- 
volved in  it ;  and  the  melted  ore  must  be 
covered  with  charcoal  powder,  to  prevent 
the  oxidation  of  its  surface. 

4.  No  flux  or  other  substance,  except- 
ing the  scoria  of  former  smeltings  which 
contains  some  tin,  are  to  be  added,  to  fa- 
cilitate the  fusion. 

Ores  of  Tungsten,  and  Ores  of  Uranium. 
are  not  much  known. 

Ores  of  Zinc. 
This  metal  has  not  been  found  in  a  na 
live  state. 
All  the  ores  of  zinc  tinge  plates  of  cop 


ORE 


ORE 


per  of  a  yellow  colour,  when  stratified  I 
with  that  metal  and  charcoal  s  but  for  this  | 
purpose  the  sulphureous  ores  must  be  i 
previously  roasted.  The  ores  of  zinc  are  j 
either  oxides,  carbonats,  sulphats,  or  sul- 1 
phurets. 

Mr.  Steinhauer,  of  Fulneck,  says,  that 
a  native  oxide,  scarely  inferior  to  the  flow- 
ers of  zinc  of  the  shops,  is  found  in  consi- 
derable quantity  in  the  West-riding-  of 
Yorkshire,  England.  In  general  it  is  mix- 
ed with  iron,  silex,  and  alumine  in  variable 
proportions,  and  is  known  by  the  name  of 
calamine. 

Its  colour  is  white,  gray,  yellow,  brown 
or  red,  and  of  various  degrees  of  hard- 
ness, though  scarce  ever  so  hard  as  to  | 
strike  fire  with  steel;  its  texture  equable  j 
or  cellular,  and  its  form  either  irregular,  j 


crystallized,  or  stalactitical ;  when  cal- 


cined it  lo&es  no  part  of  its  weight,  except  I 
it  be  mixed  with  charcoal,  and  then  How- ! 
ers  of  zinc  sublime  ;  it  is  soluble  in  acids,  j 
and  with  the  sulphuric  affords  sulphat  of  j 
iron  as  well  as  of  zinc,  which  shows  the  ' 
iron  ft  contains  is  not  much  oxided.  The  j 
specific  gravity  of  the  best  sort,  that  is,  ! 
the  gray,  is  5  i  100  parts  of  this  afforded  \ 
Berg-man  84  of  oxide  of  zinc,  3  of  iron,  1  { 
of  alumine,  and  12  of  silex ;  but  in  other 
specimens  these  proportions  are  very  dif-  j 
ferent;  some  ores  are  so  poor  as  not  to  j 
contain  above  4  per  cent,  of  oxide  of  zinc ; 
a  good  ore  should  afford  at  least  30  per  ! 
cent.,  and  its  specific  gravity  be  about  4  4 
or  5. 

Sometimes  calamines  contain  a  mixture 
of  calcareous  earth  and  lead.  Indeed 
most  of  the  English  calamines  contain 
lead. 

Berg-man  gives  us  two  methods  of  ana- ! 
lysing  calamine.    The  first  is  to  oxide  it 
in  the  nitric  acid  with  the  assistance  of 
heat,  and  boil  away  the  acid  to  dim  ness. 
Repeat  this  operation  twice  or  thrice, 
using  each  time  twice  as  much  of  the  acid 
as  the  ore  weighs ;  and  lastly,  dissolve  all  j 
that  is  soluble  in  a  fresh  portion  of  nitric  j 
acid:  by  this  means  the  zinc  (and  lead  if 
any)  with  the  alumine  will  be  taken  up, : 
while  the  iron,  being  highly  oxided,  will, 
with  the  silex,  remain  undissolved.  If  the  j 
solution  contain  lead,  the  muriatic  acid ' 
will  precipitate  it;  after  which  the  sul-1 
phuric  may  be  used  to  precipitate  the  i 
lime,  if  any  be  contained  in  the  ore,  or  the  1 
lead  and  other  metals  may  be  precipitated  1 
by  adding  a  piece  of  zinc.   The  zinc  may  | 
then  be  precipitated  by  the  prussiat  of] 
potash,  the  weight  of  which,  divided  by  , 
five,  gives  that  of  zinc  in  its  metallic  form  j 
contained  in  the  ore.  The  undissolved  re- 
siduum should  be  treated  with  three  times  j 
its  weight  of  concentrated  sulphuric  acid, 


and  evaporated  to  dryness,  and  all  that  is 
soluble  extracted  with  warm  water ;  the 
iron  should  be  precipitated  by  the  prus- 
siat of  potash,  and  the  alum'n.e  by  the  car- 
bonat  of  soda,  which  should  also  be  add- 
ed to  the  nitric  solution  after  the  zinc  is 
precipitated. 

The  second  method  is  shorter  and  more 
ingenious.  He  distills  the  sulphuric  acid 
over  calamine  to  dryness ;  the  residuum 
he  lixiviates  in  hot  water;  what  remains 
undissolved  is  silex ;  to  the  solution  he 
adds  pure  ammonia,  which  precipitates 
the  iron  and  alumine,  but  keeps  the  zinc 
in  solution,  as  it  is-  soluble  in  sulphat  of 
ammonia :  the  precipitate  he  redissolves 
in  sulphuric  acid,  and  separates  the  iron 
and  alumine  as  before. 

In  the  ore  of  tutenague  the  oxide  of 
zinc  is  mixed  with  a  notable  proportion 
of  iron.  Engestrom,  in  the  Memoirs  of 
Stockholm  for  the  year  1775,  has  given 
us  an  analysis  of  an  ore  of  this  sort  from 
China;  it  was  of  a  white  colour,  inter- 
spersed with  red  streaks  of  oxide  of  iron, 
and  so  brittle  as  to  be  easily  broken  be- 
twixt the  fingers.  It  was  soluble  in  the 
mineral  acids,  particularly  with  the  assist- 
ance of  heat ;  and  with  the  sulphuric  af- 
forded sulphats  both  of  zinc  and  iron  ;  the 
quantity  of  carbonic  acid  was  so  small  as 
to  be  absorbed  by  the  solution ;  it  con- 
tained in  various  specimens  from  60  to  90 
per  cent,  of  zinc  ;  the  remainder  was  iron 
and  a  small  proportion  of  alumine.  Bind- 
heim  also  discovered  this  variety  in  Ger- 
many, and  found  it  to  consist  of  zinc,  a 
little  iron,  and  silex. 

Of  a  similar  nature  appears  to  be  a  sin. 
gular  mineral  lately  discovered  in  the 
mine  of  Fahlun,  in  S'weden,  by  Mr.  Gahn, 
and  thence  called  Gahnite  zinc  by  Brong- 
niart.  It  is  the  automalite  of  Eckeberg  ; 
zinciferous  corundum  of  Hissinger.  In 
its  properties  it  appioaches  the  spinel  and 
ccylanite.  It  is  crystallized  in  very  regu- 
lar octoedra  ;  sufficiently  hard  to  scratch 
quartz  ;  a  non-conductor  of  electricity ; 
infusible  by  the  blowpipe  alone,  but  with 
borax  melts  into  a  green  glass,  that  be- 
comes colourless  on  cooling.  The  crys- 
tals are  small.  Their  longitudinal  frac- 
ture foliated,  transverse,  uneven,  and 
somewhat  conchoidal  Their  specific  gra- 
vity, according  to  Eckeberg,  4.261 ;  ac- 
cording to  Haiiy,  4  697 

Eckeberg,  who  first  analysed  this  mine- 
ral, gives  as  its  constituent  parts,  oxide 
of  zinc  0.24,  alumine  0.60,  silex  0.05,  iron 
0.09,  sulphur  and  loss  0.02.  Vauquelin 
found  in  it  oxide  of  zinc  0  28,  alumine 
0.42,  silex  0.04,  iron  0.05,  sulphur  and 
loss  0.17;  beside  0.04  of  the  stone,  that 
remained  unaltered. 


ORE 


ORE 


The  vitreous  zinc  ore,  or  zinc  spar,  is 
s.  carbonat  of  zinc,  of  a  whitish-gray, 
Mueish-gray,  or  yellowish  colour,  and  of  a 
hardness  generally  sufficient  to  strike  fire 
with  steel.  In  its  fracture  it  resembles 
quartz,  irregular,  stalactitical,  or  crystal- 
lized in  groups,  and  weighty ;  by  calci- 
nation it  loses  one  third  of  its  weight, 
without  emitting  a  sulphureous  or  arseni- 
cal smell,  and  is  infusible  in  the  strongest 
heat,  either  singly,  or  with  soda,  but  easi- 
ly fusible  with  borax  or  microcosmic  salt. 
In  the  mineral  acids  it  is  soluble  with  ef- 
fervescence, and  with  the  sulphuric  af- 
fords sulphat  of  zinc.  One  hundred  grains 
of  this  ore  contain  about  65  of  the  oxide 
of  zinc,  28  of  carbonic  acid,  six  of  water, 
and  one  of  iron  ;  and  sometimes  a  little  of 
si  lex. 

Bergman  suspects  the  substance  called 
zinc  spar  by  Baron  Born  to  be  a  different 
substance.  Bindheim  found  it  insoluble 
in  acids  before  calcination,  and  in  the  dry 
way  infusible  with  the  three  usual  fluxes ; 
but  after  calcination  it  becomes  soluble  in 
acids. 

Haiiy  found,  that  the  crystallized  native 
oxide  of  zinc  is  rendered  electric  by  heat 
without  friction. 

The  zeolitiform  ore  of  zinc  is  a  carbo- 
nat mixed  with  a  notable  proportion  of  si- 
lex.  The  real  contents  of  this  substance 
were  first  discovered  by  Pelletier.  It  was 
long  taken  for  a  zeolite,  being  of  a  pearl 
colour,  crystallized,  semitransparent,  con- 
sisting of  laminae  diverging  from  differ- 
ent centres,  and  becoming  gelatinous  with 
acids.  It  was  commonly  called  zeolite  of 
Friburgh.  He  found  100  grains  of  it  to 
contain  from  48  to  52  of  quartz,  36  of 
carbonat  of  zinc,  and  eight  or  12  of  wa- 
ter. 

These  ores  are  easily  analysed  in  the 
moist  way,  by  dissolving  them  in  the  di- 
lute sulphuric  acid :  the  silex,  if  any,  will 
remain  undissolved ;  and  the  zinc  and 
iron  are  taken  up,  and  may  be  separated 
by  adding  a  piece  of  zinc  previously 
weighed,  and  boiling  the  solution ;  by 
which  the  iron  will  be  precipitated.  The 
solution,  which  then  contains  only  zinc, 
should  be  precipitated  by  carbonat  of  so- 
da. One  hundred  and  ninety-three  grains 
of  this  precipitate  are  equivalent  to  100 
of  zinc  in  its  metallic  form,  from  which 
the  weight  lost  by  the  inserted  zinc  should 
be  subtracted  ;  the  weight  of  the  carbo- 
nic acid  and  water  may  be  collected  by 
comparing  the  loss  of  weight  which  the 
ore  suffers  by  calcination  and  solution  in 
acids. 

Of  the  ores  of  zinc  which  are  mineral- 
ized by  sulphur,  or  ore  blendes,  there  are 


several  varieties.  They  are  generally  of 
a  lamellar  or  scaly  texture,  and  frequent- 
ly of  a  quadrangular  form,  resembling 
galena ;  they  all  lose  much  of  their  weight 
when  heated,  and  burn  with  a  blue  flame; 
their  specific  gravity  is  inferior  to  that  of 
galena.  Almost  ali  contain  a  mixture  of 
lead  ore ;  most  of  them  exhale  a  sulphu- 
reous smell  when  scraped,  or  at  least 
when  sulphuric  or  muriatic  acid  is  drop- 
ped on  them.  Werner  divides  them  into 
three  species  by  their  colours  ;  the  yel- 
low, brown,  and  black. 

The  phosphorescent  blende  is  general  - 
ly  greenish,  yellowish-green,  or  red,  of 
different  degrees  of  transparency,  or 
opake.  When  scraped  with  a  knife  in  the 
dark,  it  emits  light,  even  in  water ;  and 
after  undergoing  a  white  heat,  when  dis- 
tilled per  se,  a  siliceous  sublimate  rises, 
which  shews  it  contains  the  sparry  acid, 
probably  united  to  a  metal,  since  it  sub- 
limes. It  is  almost  wholly  soluble  in  the 
muriatic  acid  in  a  boiling  heat. 

Bergman  found  100  parts  of  that  of 
Scharfenberg  to  contain  64  of  zinc,  five 
of  iron,  20  of  sulphur,  four  of  fluor  acid, 
six  of  water,  and  one  of  silex. 

A  sulphuret  of  zinc  was  lately  met  with 
in  one  of  the  Gwennap  mines,  incrusting 
a  spongy  pyrites  intermixed  with  quartz, 
and  so  like  wood-tin,  as  to  be  supposed  a 
variety  of  it  by  the  miners.  According 
to  Dr  Kidd,  it  consists  of  66  oxide  of 
zinc,  33  sulphur,  and  a  very  minute  por- 
tion of  iron.   The  pyrites  contains  cobalt. 

In  the  dry  way  zinc  is  reduced  by  dis- 
tilling its  ore  after  torrefaction,  with  a 
mixture  of  its  own  weight  of  charcoal, 
in  an  earthen  retort  well  luted,  and  a 
strong  heat :  but  by  this  method  scarce 
half  the  zinc  it  contains  is  obtained. 

The  first  dressing  of  calamine  for  the 
large  works  of  zinc  consists  in  picking  out 
all  the  pieces  of  lead  ore,  lime,  and  iron- 
stone, cauk,  and  other  heterogeneous  sub- 
stances, which  are  found  mixed  with  it 
in  the  mine:  it  is  then  roasted  in  proper 
furnaces,  where  it  loses  about  a  third  or 
fourth  part  of  its  weight.  It  is  picked 
out  again  very  carefully,  as  the  hetero- 
geneous particles  have  become  more  dis- 
cernible, by  the  action  of  the  fire ;  it  is 
then  ground  to  a  fine  powder,  and  wash- 
ed in  a  gentle  rill  of  water,  which  carries 
off  the  earthy  mixtures  of  extraneous 
matters ;  so  that,  by  these  processes,  a 
ton  of  the  crude  calamine  of  Derbyshire 
is  reduced  to  12  cwt.  only. 

Bergman  affirms,  that  a  certain  Eng- 
lishman, whose  name  he  does  not  men- 
tion, made,  several  years  ago,  a  voyage 
to  China,  for  the  purpose  of  learning  the 


ORE 


OBI 


art  of  smelting  zinc,  or  tutenaguc  ;  and 
that  he  became  instructed  in  the  secret, 
and  returned  safely  home. 

It  is  not  improbable,  but  that  a  fact  of 
this  kind  may  have  served  to  establish  the 
manufactory  of  zinc  in  England  about  the 
year  1743,  when  Mr.  Champion  obtained 
a  patent  for  the  making  of  it,  and  built 
the  first  work  of  the  kind  near  Bristol. 
It  consists,  as  Watson  relates,  of  a  circu. 
lar  kind  of  oven,  like  a  glass-house  fur- 
nace, in  which  were  placed  six  pots,  of 
about  four  feet  each  in  height,  much  re- 
sembling large  oil-jars  in  shape  ;  into  the 
bottom  of  each  poi  is  inserted  an  iron 
tube  which  passes  through  the  floor  of 
the  furnace,  into  a  vessel  of  water.  A 
mixtuce  of  the  prepared  ore  is  made  with 
charcoal,  and  the  pots  are  filled  with  it  to 
the  mouth,  which  are  then  close  stopped 
with  strong  covers,  and  luted  with  clay. 
The  fire  being  properly  applied,  the  me- 
tallic vapour  of  the  calamine  issues,  down- 
wards, or  per  descensum,  through  the  iron 
tubes,  there  being  no  other  place  through 
which  it  can  escape ;  and  the  air  being 
excluded,  it  does  not  take  fire,  but  is  con- 
densed in  the  water  into  granulated  par- 
ticles ;  which,  being  remelted,  are  cast  in- 
to ingots,  and  sent  to  Birmingham  under 
the  name  of  zinc,  or  spelter ;  although  by 
this  last  name  of  spelter,  only  a  granulat- 
ed kind  of  soft  brass  is  understood  among 
the  braziers,  and  others  who  work  in 
London,  used  to  solder  pieces  of  brass  to 
gether. 

Great  part  of  the  zinc  volatilized  by 
the  force  of  tire,  in  large  furnaces,  as 
those  at  Goslar,  adheres  to  their  sides  in 
the  form  of  a  whitish  oxide  :  this  is  scrap- 
ed off  when  the  furnace  is  cold,  and  is 
called  by  the  name  of  ofenbruch,  or  cad- 
mia,  which  is  employed,  as  well  as  zinc, 
to  make  brass. 

Centner,  or  Docimastic  Hundred,  in  Me- 
tallurgy and  Assaying,  is  a  weight  divisi- 
ble, first  into  an  hundred,  and  thence  into 
a  greater  number  of  other  smaller  parts  ; 
but  though  the  word  is  the  same,  both 
with  the  assayers  and  metallurgists,  yet 
it  is  to  be  understood  as  expressing  a  very 
different  quantity,  in  their  different  accep- 
tation of  it.  The  weights  of  the  metallur- 
gists are  easily  understood,  as  being  of 
the  common  proportion,  but  those  of  the 
assayers,  are  a  thousand  times  smaller 
than  these,  as  the  portions  of  metals  or 
ores  examined  by  the  assayers,  are  usually 
very  small. 

The  metallurgists,  who  extract  metals 
out  of  their  ores,  use  a  weight  divided  into 
an  hundred  equal  parts,  each  part  a  pound; 
the  whole  they  call  a  centner  or  hundred 
weight ;  the  pound  is  divided  into  thirty- 
VOL.  II. 


two  parts,  or  half  ovmce ;  and  the  half 

ounce  into  two  quarters  of  ounces,  and 
these  each  into  two  drachms. 

These  divisions  and  denominations  of 
the  metallurgists  are  easily  understood  ; 
but  the  same  words,  though  they  are 
equally  used  by  assayers,  with  them  ex- 
press very  different  quantities  ;  for  as  the 
centner  of  the  metallurgists,  contains  a 
hundred  pounds,  the  centner  of  the  as- 
saj  ers,  is  really  no  more  than  one  drachm, 
to  which  the  other  parts  are  proportion- 
ed. » 

As  the  assayers'  weights  are  divided 
into  such  an  extreme  degree  of  minute- 
ness and  are  so  very  different  from  all  the 
common  weight,  the  assayers  usually 
make  them  themselves,  in  the  following* 
manner,  out  of  small  silver,  or  fine  solder 
plates,  of  such  a  size,  that  the  mark  or 
their  weight  according  to  the  division  of 
the  drachm,  which  is  the  docimastic,  or 
assaying  centner,  may  be  upon  them. 
They  first  take  for  a  basis  one  weight, 
being  about  two-thirds  of  a  common 
drachm :  this  they  mark  (64lb.)  Then 
having  at  hand  some  granulated  lead, 
washed  clean,  well  dried,  and  sifted  very 
fine,  they  put  as  much  of  it  in  one  of  the 
small  dishes  of  a  fine  balance,  as  will  equi- 
poise the  641b.  (as  it  is  called)  just  men- 
tioned :  then  dividing  this  granulated  lead 
into  very  nice  halves,  in  the  two  scales,  af- 
ter taking  out  the  first  silver  weight,  they 
obtain  a  perfect  equilibrium  between  the 
two  scales  ;  they  then  pour  the  granulat- 
ed lead  out  of  one  dish  of  the  scales,  and 
instead  of  it,  put  in  another  silver  weight, 
which  they  make  exactly  equiponderant 
with  the  lead  in  the  other  scale,  and  mark 
it  (321b.)  If  this  second  weight,  when 
first  put  into  the  scale,  exceed  by  much 
the  weight  of  the  lead,  they  take  a  little 
from  it  by  a  very  fine  file  :  but  when  it 
comes  very  near,  they  use  only  a  whet- 
stone, to  wear  off  an  extremely  small  por- 
tion at  a  time.  When  it  is  brought  to  be 
perfectly  even  and  equal  to  the  lead,  they 
change  the  scales  to  see  that  no  error  has 
been  committed,  and  then  to  go  on  in  the 
same  manner,  till  they  have  made  all  the 
divisions,  and  all  the  small  weights.  Then 
to  have  an  entire  centner  or  hundred 
weight,  they  add  to  the  64ib.  (as  they  call 
it)  a  32ib.  anda4lb.  and  weighing  against 
them  one  small  weight,  they  make  it  equal 
to  them,  and  mark  it  (101b.)  This  is  the 
docimistical,  or  assaying  centner,  and  is 
really  one  drachm.  Cramer,  Art.  Ass.  p. 
108.  " 

ORIENTAL. — Precious  stones  from  the 
East  have  been  supposed  to  be  harder 
and  more  brilliant  than  those  which  come 
from  South  America.    How  far  this  may 

r  f 


OSM 


OVE 


really  be  the  case,  is  not  perhaps  easy  to 
be  determined.  Jewellers  use  the  words 
oriental  and  occidental  to  denote  the  su- 
perior or  inferior  quality  of  a  gem,  with- 
out giving-  themselves  any  trouble  about 
the  place  it  came  from.  Thus  an  orien- 
tal topaz  is  one  of  the  best,  whether  it 
comes  from  the  East  Indies  or  not;  and 
the  inferior  stones  or  coloured  quartz  are 
called  occidental  topazes,  though  some 
of  them  perhaps  may  come  from  the  East 
ORIGANUM  —An  essential  oil  is  kept 
in  the  shops  under  the  name  of  the  oil  of 
origanum,  which  is  obtained  from  the 
leaves  of  the  origanum  vulgare  Linn  si,  or 
wild  marjoram.    See  Ore. 

ORPIMENT. — A  combination  of  arse- 
nic with  sulphur,  of  a  yellow  colour.  See 
Colour-Making. 

ORRIS. — The  dry  roots  of  the  Florence 
iris  or  oris  (iris  alba  Florentina,  C-  B.) 
are  entirely  mild,  and  said  to  be  a  medi- 
cine of  good  service  in  disorders  of  the 
breast  They  have  a  pleasant  sweet  smell 
resembling  that  of  violets,  and  hence  are 
employed  in  sweet-scented  powders,  for 
flavouring  liqueurs,  &c.  The  distilled 
water  smells  a  little  of  the  root,  but  ex- 
hibits no  appearance  of  oil:  the  distilled 
spirit  also  has  some  slight  smell.  The 
strongest  preparation  both  in  smell  and 
taste  is  the  spirituous  extract,  this  con- 
taining nearly  all  the  active  parts  of  the 
root  concentrated  into  a  small  volume. 
An  ounce  of  the  root  yielded  a  drachm 
and  17  grains  of  spirituous,  and  afterward 
a  drachm  and  40  grains  of  watery  ex- 
tract: w^ater  applied  at  first  extracted 
from  the  same  quantity  three  drachms, 
and  spirit  afterward  only  eight  grains. 
The  extract  made  by  water  at  first  both 
tastes  and  smells  of  the  orris,  though  not 
near  so  strongly  as  the  spirituous 

OSMIUM  —A  new  metal  lately  disco- 
vered by  Mr.  Tennent  among  platina,  and 
thus  called  by  him  from'  the  pungent  and 
peculiar  smell  of  its  oxide. 

Its  oxide  may  be  obtained  in  small 
quantity  by  distilling  with  nitre  the  black 
powder  left  after  dissolving  platina ;  when 
at  a  low  red  heat  an  apparently  oily  fluid 
sub'imes  into  the  neck  of  the  retort, 
which  on  cooling  concretes  into  a  solid 
colourless,  semitransparent  mass.  This 
being  dissolved  in  water,  forms  a  concen- 
trated solution  of  oxide  of  osmium.  This 
solution  gives  a  dark  stain  to  the  skin, 
that  cannot  be  effaced.  Infusion  of  galls 
presently  produces  a  purple  colour  in  it, 
which  soon  after  becomes  of  a  deep  vivid 
blue.  This  is  the  best  test  of  the  oxide. 
"With  pure  ammonia  it  becomes  yellow, 
and  slightly  so  with  carbonat  of  soda. 
With  lime  it  forms  a  bright  yellow  solu- 


tion ;  but  it  is  not  affected  either  by  chalk 
or  by  pure  magnesia.  The  solution  with 
lime  gives  a  deep  red  precipitate  with 
galls,  which  is  turned  blue  by  acids.  It 
produces  no  effect  on  solution  of  gold  or 
platina;  but  precipitates  lead  of  a  yellow- 
ish brown,  mercury  of  a  white,  and  mu- 
riat  of  tin  of  a  brown  colour. 

OSMUND1C  EARTH.  See  Earth, 
Fullers 

OSTEOCOLLA,  is  a  substance  formed 
by  stony  matters  filling  up  the  interstices 
of  rotten  roots  of  trees.  It  has  been  par- 
ticularly described  by  Mr.  Gleditsch,  and 
examined  chemically  by  Mr.  Margraaf,, 
See  Memoirs  of  the  Berlin  Academy  for 
the  year  1748.  The  former  author  relates, 
that  it  is  dug  from  grounds  containing 
fine  sand  and  a  fine  calcareous  earth  ;  and 
that  sometimes  the  roots  of  living  trees 
had  been  found  converted  into  this  stony 
substance.  From  Margraafs  experi- 
ments it  appears,  that  the  osteocolla  exa- 
mined by  him  was  composed  of  a  fine 
sand,  a  fine  calcareous  earth,  and  some 
rotten  remains  of  a  root.  Neuman  says, 
that  he  found  muriatic  acid  in  osteocolla. 
But  nothing  of  that  or  any  other  acid 
could  be  discovered  by  Margraaf.  Neu- 
mann also  says,  that  he  toiaily  dissolved 
osteocolla  by  means  of  dilute  sulphuric 
acid.  Hence  the  substances  examined  by 
these  two  chemists  seem  to  have  been 
different.  Differences  must  arise  from  the 
different  qualities  of  the  soil  in  which  os- 
teocolla is  found. 

OSTRICH'S  DOWN,  called  otherwise 
ostrich's  hair,  and  sometimes  wool,  is  of 
two  sorts  ;  that  called  the  fine  of  ostrich, 
is  used  by  hatters  in  the  manufacture  of 
common  bats ;  and  that  called  coarse  of 
ostrich,  serves  for  the  making  of  list  for 
fine  white  cloth. 

OTTA,  or  Atyr  of  Roses. — The  es- 
sential oil  of  roses.  It  comes  to  us  under 
this  name  from  Bengal,  and  is  of  too  high 
price  to  become  an  article  of  commerce  in 
England.  From  a  variety  of  accounts 
we  learn,  that  it  is  obtained  in  the  usual 
method,  viz.  by  the  distillation  of  rose 
leaves  with  wrater,  and  that  a  prodigious 
quantity  of  roses  affords  but  a  small  pro- 
portion of  the  oil.  It  is  said  to  be  equal 
in  fragrance  to  a  new-blown  rose.  This 
perhaps  may  be  true  of  the  oil  when  new- 
ly distilled;  but  in  the  few  specimens 
which  have  come  under  our  observation, 
the  difference  in  scent  appears  to  be  near- 
ly as  great  as  between  most  other  essen- 
tial oils  and  the  vegetables  which  afford 
them     See  Oil. 

OVEN — A  kind  of  domestic  furnace, 
used  for  baking  bread,  pies,  tarts,  &c. 

Ovens  are  generally  constructed  of 


OYS 


OXY 


fcriek-work.in  a  semi-circular  form,  with 
a  very  low  roof,  and  the  bottoms  are 
laid  with  stone:  in  the  front  is  a  small 
aperture  and  door,  by  the  shutting  of 
which,  the  heat  is  confined  while  the 
bread  is  baking-.  They  are  usually  heat- 
ed by  means  of  dry  faggots,  wood,  &c. 
As  these  ovens,  however,  are  not  calcu- 
lated for  small  families,  on  account  of  the 
quantity  of  fuel  they  consume,  others 
have  been  contrived,  on  a  more  diminu- 
tive scale  :  these  are  usually  formed  of 
cast  or  hammered  iron,  and  may  be  heat- 
ed by  the  same  fire  which  serves  for  the 
cooking1  of  other  provisions. 

Among  the  ovens  of  this  construction, 
that  of  Mr.  Powers,  who  obtained  for  it  a 
patent  in  1801,  deserves  to  be  noticed.  It 
is  formed  of  iron,  so  as  to  be  portable, 
and  may  be.conveniently  conveyed  to  any 
distance,  at  the  option  of  its  possessor  ; 
but,  as  the  reader  cannot  form  a  distinct 
idea  of  this  contrivance,  without  the  aid 
of  an  engraving-,  we  refer  him  to  the  14th 
vol.  of  tlie  Repertory  of  Arts,  &c.  where 
the  patent  is  described,  and  illustrated 
with  a  plate. 

In  the  year  1 800,  the  London  Society  for 
Encouragement  of  Arts,  Sec.  conferred  a 
bounty  of  15  g-uineas  on  Mr.  S.  Holmes, 
for  his  invention  of  an  oven,  which  is 
heated  without  flues.  The  whole  con- 
sists of  a  cast-iron  stove,  from  the  side  of 
which  a  solid  piece  of  that  metal  projects 
into  the  fire,  where  it  constantly  remains  ; 
and,  on  becoming-  red-hot,  communicates 
to  the  whole  oven  a  degree  of  heat  suffi- 
cient for  baking'  bread,  while  it  at  the 
same  time  assists  the  fire  in  roasting-  the 
Bleat. 

In  the  common  iron  ovens,  the  heat  is 
communicated  by  means  of  flues,  which 
waste  a  considerable  part  of  the  fire  in 
its  passage,  and  likewise  require  much 
labour  to  keep  them  of  an  uniform  heat. 
The  contrivance  last  alluded  to,  is  intend- 
ed to  supply  this  and  other  inconvenien- 
ces :  and  Mr.  Holmes  states,  that  his  oven 
uniformly  remains  at  a  baking-  heat,  with- 
out any  additional  expense,  or  trouble. 
We  understand,  however,  that  such  im- 
provement is  by  no  means  new  ;  and  that 
a  similar  method  of  saving  fuel,  has  for 
several  years  been  practised  in  the  west 
of  England. 

This  subject  will  probably  be  noticed 
under  the  article  Stove. 

OYSTER  SHELL  LIME. — The  shells 
of  the  oyster,  like  those  of  other  crusta- 
ceous  fish,  are  composed  of  calcareous 
earth,  and  animal  glue.  They  possess  no 
medicinal  virtue  superior  to  common  lime- 
stone or  chalk  ;  but,  by  calcination,  they 
yield  a  quick -lime,  which  is  perfectly  free 


from  any  metallic  or  other  fossil  sub- 
stance ;  and  being  less  permeable  to  wa« 
ter,  when  mixed  with  sand,  it  is  better 
calculated  for  the  plaistering  of  walls  in 
damp  situations.  Hence  the  Dutch  pre- 
pare their  excellent  mortar  generally  of 
marine  shells  burnt  into  lime ;  which 
makes  a  most  durable  cement.  The  great 
importance  of  this  fact,  in  point  of  health 
and  economy,  deserves  equal  attention ; 
so  that  the  immense  quantities  of  oyster- 
shells  annually  thrown  away  in  cities, 
might  easily  be  converted  into  a  very  use- 
ful shell-lime. 

It  is  a  custom  in  different  parts  of  the 
United  States,  where  lime-stone  is  scarce, 
and  marine  shells  in  abundance,  to  pro- 
duce lime  by  the  calcination  or  burning 
of  shells.  For  this  purpose,  the  oyster- 
shell  is  used. 

In  New-Orleans,  this  practice  is  com- 
mon ;  and  excellent  lime  is  obtained.  We 
think,  that  however  cheap  lime  may  be 
which  is  procured  from  lime-stone,  even 
in  our  cities,  the  burning  of  oyster-shells 
would  rt-pay  the  expense,  and  yield  a 
handsome  profit.  The  quantity  of  shell 
is  immense,  although  at  first  view  they 
would  appear  few. 

OX.    See  Animals,  Domestic. 

OXYGEN  GAS. — As  we  have  noticed 
oxygen  very  frequently,  we  shall  here  say 
something  on  the  subject. 

This  gas  was  obtained  by  Dr.  Priestley 
in  1774  from  red  oxyde  of  mercury,  ex- 
posed to  a  burning  lens,  who  observed  its 
distinguishing  properties  of  rendering 
combustion  more  vivid  and  eminently  sup- 
porting life.  Scheele  obtained  it  in  dif- 
ferent modes  in  1775;  and  in  the  same 
year  Lavoisier,  who  had  begun,  as  he 
says,  to  suspect  the  absorption  of  atmos- 
pheric air,  or  a  portion  of  it,  in  the  calci- 
nation of  metals,  expelled  it  from  the  red 
oxyde  of  mercury  heated  in  a  retort. 
Priestley,  agreeably  to  his  theory,  called 
it  depIUugisticated  air;  Scheele,  from  its 
peculiar  property,  fire  air,  a  name  before 
given  it  by  M  ay  on,  or  empyre  al  air;  La- 
voisier, air  eminently  pure,  and  afterward 
eminently  respirable,  which  Condorcet  al- 
tered to  vital  air  ;  a  term  to  which  per- 
haps there  is  no  objection,  but  its  intract~ 
ability  when  wanted  in  compound  names. 
Bergman's  term,  pure  air,  as  well  as  La- 
voisier's eminently  pure,  is  not  distinctive. 
When  the  French  chemists  commenced 
their  complete  system  of  reform  of  the. 
chemical  nomenclature,  finding  the  bases 
of  this  gas  present  in  every  compound  that 
possessed  acid  properties,  and  consider- 
ing it  as  the  acidifying  principle,  they 
gave  it  the  name  of  oxygen,  which  it  still 
retains,  notwithstanding-  some  anomalies 


OXY 


OXY 


with  regard  to  this  quality  have  since 
been  observed. 

Oxygen  gas  forms  about  a  fourth  of  our 
atmosphere,  and  its  base  is  very  abundant 
in  nature.  Water  contains  .85  of  it :  and 
it  exists  in  most  vegetable  and  animal  pro- 
ducts, acids,  salts,  and  oxydes. 

This  gas  may  be  obtained  from  nitrat  of 
potash,  (common  saltpetre)  exposed  to  a 
red  heat  in  a  coated  glass  or  earthen  retort, 
or  in  a  gun  barrel ;  from  a  pound  of  which 
about  1200  cubic  inches  may  be  obtained  ; 
but  this  is  liable,  particularly  toward  the 
end  of  the  process,  to  a  mixture  of  nitrogen. 
It  may  be  expelled,  as  already  observed, 
from  the  red  oxyde  of  mercury,  or  that  of 
lead ;  and  still  better  from  the  black  oxyde 
of  manganese,  heated  red-hot  in  a  gun  bar- 
rel, or  exposed  to  a  gentler  heat  in  a  re- 
tort with  half  its  weight,  or  somewhat 
more,  of  strong  sulphuric  acid.  To  ob- 
tain it  of  the  greatest  purity,  however, 
the  hyperoxymuriat  of  potash  is  prefera- 
ble to  any  other  substance,  rejecting  the 
portions  that  first  come  over,  as  being  de- 
based with  the  atmospheric  air  in  the  re- 
tort. Growing  vegetables,  exposed  to  the 
solar  light,  gave  out  oxygen  gas  ;  so  do 
leaves  laid  n  water  in  similar  situations, 
the  green  matter  that  forms  in  water,  and 
some  other  substances. 

Oxygen  gas  has  neither  smell  nor  taste. 
It  is  a  little  heavier  than  atmospheric  air. 
Under  great  pressure  water  may  be  made 
to  take  up  about  half  its  bulk.  It  is  es- 
sential to  the  support  of  life :  an  animal 
will  live  in  it  a  considerable  time  longer 
than  in  atmospheric  air ;  but  its  respira- 
tion becomes  hurried  and  laborious  before 
the  whole  is  consumed,  and  it  dies, 
though  a  fresh  animal  <jf  the  same  kind 
can  still  sustain  life  for  a  certain  time  in 
the  residuary  ah 

Combustion  is  powerfully  supported  by 
oxygen  gas.  Any  inflammable  substance, 
previously  kindled,  and  introduced  into  it, 
burns  rapidly  and  vividly.  If  an  iron  or 
copper  wire  "be  introduced  into  a  bottle  of 
oxygen  gas,  with  a  bit  of  lighted  touch- 
wood or  charcoal  at  the  end,"  it  will  burn 
with  a  bright  light,  and  throw  out  a  num- 
ber of  sparks.  The  bottom  of  the  bottle 
should  be  covered  with  sand,  that  these 
sparks  may  not  crack  it.  Mr.  Accum 
says,  a  thick  piece  of  iron  or  steel,  as  a 
file,  if  made  very  sharp  at  the  point  where 
it  is  first  kindled,  will  burn  in  this  gas.  If 
the  wire,  coiled  up  in  a  spiral  like  a  cork- 
screw, as  it  usually  is  in  this  experiment, 
be  moved  with  a  jerk  the  instant  a  melted 
globule  is  about  to  fall,  so  as  to  throw  it 
against  the  side  of  the  glass,  it  will  melt 
its  wav  through  in  an  instant. 

OXYGENATION. — The  process  of 


combining  oxygen  with  bodies  :  such  bo- 
dies as  are  thus  combined  with  oxygen, 
are  said  to  be  oxygenated,  or  oxygenized. 
Very  frequently  the  combination  forms 
an  acid;  the  base  is  therefore  acidified; 
and  sometimes  oxydized,  forming  there- 
with anbxyd. 

OXYDIZEMENT  — The  forming  of  an 
oxyd,  by  the  combination  of  a  base  with 
oxygen  :  the  name  of  the  process. 

OXYGENIZED  MURIATIC  ACID  — 
This  acid  called  also  dephlogisticated 
muriatic  acid,  is  extensively  used  in  some 
of  the  arts,  as  in  bleaching.  It  i:s  not  ne- 
cessary to  go  into  an  explanation  of  its 
properties  in  general ;  but  the  following 
observations,  we  deem  sufficient. 

It  may  be  made  by  adding  two  parts 
of  muriatic  acid,  to  one  of  finely  powder- 
ed manganese,  in  a  retort  connected  with 
Wouife's  apparatus,  and  applying  a  gentle 
heat  to  it,  while  the  receivers  are  sur- 
rounded by  water,  as  near  as  possible  to 
the  freezing  point :  or  by  mixing  8  parts  of 
muriat  of  soda,  (common  salt)  with  3  of 
powdered  manganese,  putting  them  into  a 
retort,  pouring  on  them  four  parts  of  sul- 
phuric acid,  previously  diluted  with  an 
equal  weight  of  water,  and  proceeding  as 
above.  The  operator  should  be  very  care- 
ful, that  none  of  the  acid  escapes  into  the 
air,  in  the  state  of  gas,  as  it  is  very  inju- 
rious when  respired,  occasioning  all  the 
symptoms  of  violent  catarrh,  by  coming 
into  contact  with  the  membrane,  that  lines 
the  nostrils,  and  severe  stricture  and  op- 
pression of  the  chest,  if  it  enter  the  lungs. 
The  best  preventive  of  its  mischievous 
eifects,  when  it  does  thus  escape,  is  the 
vapour  of  volatile  alkali,  for  which  it  has 
a  powerful  affinity. 

When  the  water  in  the  receivers  is  kept 
at  a  temperature  below  40°,  the  water  not 
only  saturates  itself  with  the  gas,  but  crys- 
tals, of  a  shining  greenish  white,  form  in 
hexaedral  scales  on  the  surface,  and  round 
the  sides,  enclosing  the  fluid, till  the  whole 
assume  a  gelatinous  appearance.  A  very 
moderate  heat  melts  the  concrete  matter, 
and  even  converts  it  into  a  gass,  that  rises 
in  bubbles  through  the  saturated  fluid, 
and  floats  on  its  surface.  By  increasing 
the  heat,  the  whole  of  the  gass  may  be  ex- 
pelled with  very  little  alteration  ;  but  light 
decomposes  it,  and  reduces  it  to  the  state 
of  common  muriatic  acid,  by  liberating  the 
oxygen. 

It  is  a  singular  circumstance,  that  one 
of  the  powerful  mineral  acids,  should  be 
deprived  of  what  are  considered  as  cha- 
racteristic properties  of  an  acid,  by  the 
addition  of  oxygen,  which  is  deemed  the 
acidifying  principle.  Its  taste,  instead  of 
being  sour,  is  harsh  and  styptic ;  and  in- 


OXY 


OXY 


stead  of  reddening  blue  vegetable  colours 
it  destroys  them,  as  it  does  most  others, 
yellow  excepted.  From  this  property,  it 
is  of  use  for  removing  stains,  and  disco- 
lorations  from  old  books  and  prints ; 
though  it  is  destructive  to  manuscrips,  as 
it  discharges  writing  ink ;  and  it  is  very 
extensively  employed  in  bleaching,  as  will 
be  seen  more  at  large  under  that  article. 
In  medicine  too  it  has  been  tried.  Van 
Deiman  recommends  it  in  a  dilute  state, 
against  the  itch  and  scald-head,  and  as  a 
wash  for  the  gums  when  scorbutic  :  Four- 
croy  mentions  it  as  a  powerful  tonic :  and 
Mr.  Brathwaite  of  Lancaster,  (England) 
extols  it  highly  in  doses  of  10  or  15  drops 


against  scarlet  fever.  But  we  are  not<in- 
clined  to  give  it  credit,  for  any  decided 
superiority  over  other  acids,  that  can  be 
obtained  and  administered  more  commo- 
diously. 

The  application  of  this  acid  to  bleach- 
ing in  particular,  with  the  apparatus  used 
in  modern  bleaching,  as  well  as  its  prepa- 
ration on  a  large  scale,  may  be  seen  in  the 
Appendix  to  vol.  1.  See  also  Bleach- 
ing. 

OXYMUK1ATE  OF  LIME.  Salt  used 
in  bleaching,  see  Appendix,  vol.  1. 

OXYMCRIATIC  OF  MAGNESIA. — 
Salt  used  in  bleaching,  see  Appendix, 
vol.  1. 


P. 


PAPER,  Bleaching  of.— The  bleaching 
of  paper,  or  paper  stuff,  with  oxymuriatic 
acid,  has  been  recommended  by  Mr.  Cist 
in  Cooper's  Emporium.  Mr.  C.  observes, 
"  as  the  bleaching,  by  means  of  the  oxy- 
muriatic acid  is,  I  believe,  not  known  or 
in  use  in  our  paper-mills,  it  may  be  useful 
to  the  profession  here  to  be  informed  of 
the  mode  and  process  of  conducting  in 
Europe  that  part  of  their  business,"  which 
he  gives  in  a  plain  and  familiar  manner. 
The  mode  of  making  the  bleaching  liquor 
is  the  same  as  given  under  Bleaching, 
and  in  the  Appendix  to  vol.  i :  the  pro- 
portions of  the  materials  in  the  latter  are, 
however,  more  accurate.  After  the  ob- 
servations of  Mr.  C.  which,  he  says,  were 
furnished  him  by  an  English  manufactu- 
rer, the  professor  concludes  with  some 
judicious  remarks,  which,  in  his  usual 
manner,  display  much  thought  and  eru- 
dition. 

Citizen  Loysel,  in  the  Ann.  de  Chim 
xxxix,  page  *137,  has  a  memoir  on  the 
method  of  bleaching  the  paste  of  paper. 
"With  respect  to  the  choice  and  prepara- 
tion of  rags,  he  gives  the  following  re- 
marks. 

"  The  strength  or  tenacity  of  paper  de- 
pends upon  the  staple  or  fibre  of  the  ma- 
terial from  which  it  is  made.  Rags  of  new 
cloth  and  cordage  compose  a  paper  more 
tough  than  old  rags,  and  the  first  of  these 
materials  presents  a  great  variety,  on  ac- 
count of  the  quality  of  the  hemp  or  flax 
of  which  they  are  formed.  Rags  of  fine 
new  cloth,  whether  raw  or  bleached  by 
the  oxigenated  muriatic  acid,  stand  in  the 
first  rank,  after  which  cordage  and  old 
rags  may  be  classed. 


Paper  intended  for  bills  of  exchange,  or 
other  commercial  and  legal  instruments, 
ought  to  be  tough,  in  order  that  it  may 
not  be  easily  torn  when  thin ;  for  this 
paper  the  materials  of  the  first  class  must 
be  entirely,  or  in  large  proportion,  em- 
ployed. The  price  which  consumers  are 
disposed  to  pay  for  this  article,  is  suffi- 
cient to  indemnify  the  manufacturer  for 
his  care  and  industry,  as  this  kind  of 
paper  is  sold  in  France  for  five  or  six 
francs  the  kilogram. 

The  other  papers  also  require  to  be 
more  or  less  tough,  according  to  their 
thinness,  and  the  use  to  which  they  are 
applied,  but  a  clear  white  colour  is  sought 
in  paper  of  every  description.  The  first 
operation  to  which  the  rags  are  subjected 
is  sorting,  in  order  that  each  branch  of 
the  manufacture  may  have  its  appropriate 
material,  after  which  they  are  cut  with 
shears  into  pieces  of  about  one  decimeter, 
or  three  or  four  inches  square. 

I  will  suppose  that  the  object  of  the 
manufacturer  is  to  obtain  paper  of  a  beau- 
tiful white.  If  it  is  intended  to  be  thin, 
so  that,  for  example,  a  ream  of  the  size 
denominated  raisin,  should  weigh  only 
four  or  five  kilograms,  that  is  to  say, 
about  one-third  of  the  weight  of  common 
paper  of  the  same  form.  The  manufac- 
turer makes  choice  either  of  new  rags  al- 
ready of  a  fine  white,  or  of  unbleached 
rags. 

In  the  case  of  the  white  rags,  it  is  suffi- 
cient to  pass  them  under  the  first  cylin- 
der, then  to  give  them  a  bath  of  the 
bleaching  liquor,  and  afterwards  a  bath 
of  sulphuric  acid,  as  we  shall  proceed  to 
direct ;  after  which  they  are  passed  under 


PAP 


PAP 


the  finishing  cylinder  for  seven  or  eight 
hours  ;  and,  lastly,  conveyed  to  the  work- 
ing trough  to  be  made  into  sheets  of 
paper. 

Kags,  which  have  never  been  bleached, 
may  be  treated  by  either  of  the  following 
processes,  that  is  to  say,  the  first,  which 
preserves  the  utmost  degree  of  tough- 
ness to  the  paper,  but  is  likewise  the  most 
expensive,  consists  in  decomposing  the 
rag,  and  afterwards  applying  the  method 
of  citizen  Bertholiet  for  bieaching  piece- 
goods;  namely,  subjecting  it  to  three  or 
four  lixiviations,  and  afterwards  alter- 
nately to  lixiviations,  baths  of  the  bleach- 
ing liquor,  and  baths  of  sulphuric  acid. 
The  weight  of  the  raw  unbleached  mate- 
rial is  diminished  from  50  to  45  per  cent, 
in  these  operations 

This  method  was  the  first  which  we 
used  for  the  assignat  paper ;  but  we  soon 
perceived  that  we  might  omit  most  of  the 
lixiviations  and  baths  of  the  bleaching 
fluid,  and  still  preserve  as  much  tough- 
ness as  the  paper  required.  Nothing  fur- 
ther was  necessary  for  this  purpose  than 
to  suffer  the  rag  to  undergo  a  degree  of 
fermentation  more  or  less  advanced,  by- 
leaving  it  to  rot.  In  this  operation  the 
colouring  matter  undergoes  a  slow  com- 
bustion, and  passes  to  a  kind  of  sapona- 
ceous state,  and  is  carried  off  by  the  wa- 
ter, by  washing  the  rags  in  the  vessel  of 
the  first  cylinder. 

One  single  lixiviation,  two  baths  of  the 
bleaching  liquor,  and  one  of  sulphuric 
acid,  are  then  sufficient  to  bleach  com- 
pletely the  raw  rags  or  cordage.  This  is 
the  second  method.  We  were  not,  at 
*hat  time,  acquainted  with  the  economi- 
cal process  of  citizen  Chaptal  in  the  ope- 
rations of  lixiviation.  This  will,  no  doubt, 
be  used;  but  the  effect  of  rotting,  care- 
fully conducted,  will  always  be  found 
very  advantageous. 

Lastly,  if  the  rags  be  neither  perfectly 
white  nor  raw,  and  unbleached,  but  in  a 
medium  state,  they  are  left  to  rot  for  a 
shorter  time,  for  example,  twelve  or  four- 
teen days,  and  are  taken  up  when  the 
.heat  of  the  fermentation  raises  the  ther- 
mometer to  30  or  35  degrees,  after  which 
the  process  is  to  be  conducted  as  before 
mentioned." 

PAPEIl-HAXGIXGS,  are  a  particular 
kind  of  paper,  which  is  much  thicker  than 
that  used  for  the  purposes  of  printing, 
writing,  &c. ;  so  that  it  is  manufactured 
solely  for  hanging  or  lining  the  walls  of 
rooms.  Such  papers  are  coloured  in  va- 
rious ways  ;  but,  as  a  description  of  these 
processes  would  trespass  on  our  limits, 
we  shall  merely  take  notice  of  a  patent, 
which  was  granted  in  1/93,  to  Mr.  Eck- 


hardt,  for  his  method  of  preparing  and 
priming  paper-hangings  in  different  pat- 
terns, and  silvering  them  so  as  to  resem- 
ble damask,  lace,  and  various  silk  stuffs. 
The  patentee  directs  the  paper  to  be  co- 
loured in  the  usual  manner,  and  a  proper 
coat  of  size,  consisting  of  solutions  of  isin- 
glass, or  parchment,  to  be  applied.  When 
this  ground  is  sufficienth  dry,  a  gold  size, 
or  other  preparation,  may  be  substituted, 
and  laid  on  those  parts,  on  whicii  the  or- 
naments are  intended  to  appear.  Before 
the  gold  size  is  perfectly  dry,  leaves  of  sil- 
ver are  spread  over  it ;  the  paper  is  sized 
two  or  three  times  ;  and  then  fin, shed  with 
such  varnish  as  will  resist  moisture. 

PAPEil-MAKING  Paper  is  a  word 
evidently  of  Greek  origin,  from  papyrus, 
the  name  of  a  celebrated  Egyptian  piant, 
which  was  so  much  used  by  the  ancients 
in  all  kinds  of  writing. 

We  conceive  it  unnecessary  to  describe 
particular!}  the  different  expedients  which 
men  in  every  age  and  country  have  em- 
ployed for  giving  stability  to  their  ideas, 
and  for  handing  them  down  to  their  chil- 
dren. 

On  the  first  discovery  of  the  art  of 
writing,  stones,  bricks,  leaves  of  trees,  the 
interior  and  exterior  bark,  plates  of  Head, 
wood,  wax,  and  ivory,  were  employed. 
The  progress  of  society,  and  the  conse- 
quent improvement  in  the  arts,  produced 
Egyptian  paper,  paper  of  cotton,  paper 
made  from  the  bark  of  trees,  and  in  our 
times  from  old  rags. 

To  the  most  approved  method  of  ma- 
nufacturing paper  from  this  latter  mate- 
rial we  shall  confine  ourselves ;  and  to 
i<ive  a  concise  view  of  this  subject,  it  will 
be  necessary  to  proceed  with  all  the  im- 
portant parts  of  the  operation  in  their 
order. 

The  selection  of  the  rags,  is  the  arrang- 
ing of  them  into  different  lots,  according 
to  their  quality  and  to  the  demand  of  the 
paper-mill.  In  general,  this  selection  is 
very  much  neglected:  The  degrees  of 
fineness  and  whiteness,  distinguished  with 
little  care,  are  thought  to  be  the  only  ob- 
jects of  importance;  whereas  the  hard- 
ness and  softness,  the  being  more  or 
less  worn,  are  very  essential  in  this  se- 
lection. It  is  certain,  that  a  mixture  of 
soft  and  hard  rags  occasions  much  more 
loss  in  the  trituration,  than  a  difference  in 
point  of  fineness  or  of  colour.  This  ex- 
actness in  the  selection  is  still  more  ne- 
cessary, where  cylinders  are  used  instead 
of  mallets.  We  cannot  do  better  than  to 
give  the  method  practised  in  Holland  as 
worthy  of  imitation. 

They  begin  by  a  general  separation  of 
the  rags  into  four  lots  ;  superfine,  fine, 


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middle,  and  coarse.  These  lots  are  given 
to  selectors,  who  subdivide  each  of  them 
into  five  chests.  They  have  besides  a 
bench,  on  which  is  fixed  vertically  a  hook, 
and  a  piece  of  scythe  which  is  terminated 
by  a  crooked  point. 

The  person,  for  example,  who  h:is  the 
charge  of  the  fine  lot,  puts  into  one  of  the 
chests  the  hard  rags,  or  those  which  are 
little  used,  into  another  the  soft,  into  a 
third  the  dirty,  into  a  fourth  those  Which 
are  stitched  or  hemmed,  and,  finally,  into 
the  fifth  the  superfine  rags  which  Imp- 
pens  to  be  among  die  fine. 

After  this  process,  the  women  who 
have  the  charge  of  it  are  at  extreme  pains 
to  pick  out  every  kind  of  sewing,  and  es- 
pecially the  knots  of  thread  and  the  hems, 
by  means  of  the  hook  or  scythe  which 
they  have  under  their  hands.  They  take 
care  also  by  the  same  means  to  cut  and 
reduce  the  rags  exactly  by  the  warp  and 
the  woof  into  small  pieces.  It  is  of  great 
advantage  to  cut  or  tear  the  pieces  of  rags 
by  a  thread,  whether  it  be  by  the  warp  or 
woof;  because,  if  it  is  done  obliquely, 
many  of  the  ends  are  lost  in  the  opera- 
tion. 

When  they  have  selected  a  certain 
quantity  of  each  of  these  subdivisions, 
they  are  placed  on  an  iron  grate,  which 
covers  a  large  chest  where  they  are  beat, 
and  otherwise  turned,  till  the  filth  and 
dust  pass  through  the  bars  of  the  grate 
and  fall  into  the  chest. 

The  number  of  lots  in  the  selection  of 
rags  must  be  proportioned  to  the  mass 
from  which  the  selection  is  made,  and  to 
the  kinds  of  paper  produced  by  the  mill. 
Some  mills,  the  work  of  which  is  consi- 
derable, make  nine  lots  of  tl\eir  rags,  five 
of  which  respect  the  fineness,  and  the  rest 
the  cleanness  and  the  colour.  In  ordinary 
mills  there  are  only  four  lots,  and  in  some 
two. 

We  have  already  observed,  that  the  se- 
lection which  regards  the  hardness  of 
the  materials  is  very  essential;  because 
it  is  of  great  importance  to  obtain  stuff 
composed  of  equal  parts,  and  without  any 
loss.  But  it  is  necessary  to  add,  that  the 
fineness  and  beauty  of  the  paper  depend 
in  some  cases  on  a  selection  not  rigorous. 
Thus,  for  example,  it  is  of  great  service  to 
allow  the  middle  to  retain  some  part  of 
the  fine,  and  the  fine  some  part  of  the  su- 
perfine ;  for  without  this  the  inferior  kinds 
of  paper  can  never  be  of  great  value. 
The  most  common  fault  is  to  mix  the  rags 
of  the  inferior  lots  with  the  superior  ; 
which,  though  it  augments  the  quantity 
of  paper,  is  extremely  injurious  to  the 
quality.  It  does  much  better  to  mix  part 
of  the  superior  lots  with  the  inferior.  It 


is  the  want  of  attention  to  this  mixture 
which  makes  some  paper-mills  excel  in 
the  superior  sorts  of  paper,  while  the  in- 
ferior kinds  are  of  a  very  bad  quality. 

The  selection  of  rags  being  made  with 
exactness,  however,  and  the  lots  being 
fermented  and  triturated  separately,  the 
mixture  may  be  made  with  much  greater 
advantage  when  they  are  both  reduced  to 
stuff:  always  taking  care  that  it  be  in  the 
same  proportion  as  if  it  were  in  the  state 
of  rugs,  and  only  in  the  manner  which  we 
just  now  mentioned;  for  the  inferior  sorts 
gain  more  in  beauty  and  quality  by  this 
mixture  than  is  lost  in  stuff;  whereas  if 
the  fine  stuff  receives  a  certain  quantity  of 
the  inferior,  the  paper  is  more  damaged 
in  its  value  than  increased  in  quantity.  In 
this  manner  the  interest  of  the  manufac- 
turer, as  in  all  cases,  is  intimately  con- 
nected with  the  goodness  of  his  commo- 
dities. 

In  some  mills  the  place  for  fermenta- 
tion is  divided  into  two  parts,  one  of 
which  serves  fur  v\  ashing  awav  the  filth 
from  the  rags.  After  allowing-  them  to 
steep  for  some  time  in  a  large  stone  vat, 
they  stir  them,  and  pour  in  fresh  water 
till  the  impurities  connected  with  the  rags 
run  over.  When  they  are  as  clean  as  they 
possibly  can  be  made  by  this  kind  of 
washing,  they  are  laid  in  a  heap  to  putre- 
fy. In  this  condition  thev  experience  a 
degree  of  fermentation,  which  is  firs>  dis- 
covered by  a  mouldiness  of  the  different 
pieces  of  cloth.  Afterwards  the  mass 
grows  warm  ;  and  then  it  is  of  great  con- 
sequence to  attend  the  progress  of  this 
heat,  in  order  to  moderate  its  effects :  for 
this  purpose,  the  middle  of  the  heap, 
where  the  fermentation  is  strongest,  is 
turned  out,  and  vice  versa.  In  mills  w  here 
mallets  are  used,  the  putrefaction  is  car- 
ried to  a  great  height,  which  is  frequent- 
ly attended  with  two  inconveniences.  The 
first  is,  that  a  part  of  the  rags  is  reduced 
to  an  earthy  substance,  which  is  found  in 
great  abundance  about  the  cutting-table, 
as  we  shall  afterwards  have  occasion  to 
see.  But  besides  this  waste,  excessive 
fermentation  makes  the  stuff  incapable  of 
sustaining  the  action  of  the  mallets  till  it 
is  equally  pounded  A  paper  made  from 
stuff  too  hard  and  too  little  fermented,  is 
coarse  and  ill  compacted ;  that  made  from 
rags  too  much  fermented  is  composed  of 
fibres  •  without  softness  and  without 
strength. 

The  second  inconveniency  is,  that  the 
rags  turn  greasy  by  too  much  fermenta- 
tion, and  of  consequence  it  is  very  diffi- 
cult to  separate  and  i  educe  them  by  all 
the  washings  of  the  trituration. 

We  shall  not  describe  the  form  of  the 


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place  for  fermentation,  because  in  differ- 
ent paper-works  these  places  are  of  differ- 
ent  constructions :  it  is  sufficient  to  say, 
that  they  are  all  placed  in  low  situations 
and  made  very  close.  The  selected  rags 
are  placed  in  them  in  heaps,  and  watered 
from  time  to  time  to  bring-  on  the  fermen- 
tation. In  different  paper-mills  they  prac- 
tise different  methods  in  the  putrefaction 
of  their  rags. 

In  certain  provinces  in  France,  they  lay 
in  the  place  for  putrefaction  a  heap  equi- 
valent to  what  the  mill  can  triturate  in  a 
month.  When  this  is  equally  and  suffi- 
ciently moistened  by  means  of  moveable 
pipes,  they  cover  it  with  an  old  heap, 
which  has  lain  a  month  in  a  state  of  fer- 
mentation. When  this  old  heap  is  ex- 
hausted by  the  mill,  the  new  one  becomes 
a  covering  to  another,  and  so  on.  From 
this  detail  it  is  easy  to  perceive,  that  there 
must  be  near  three  weeks  difference  of 
putrefaction  in  the  same  heap,  and  also 
that  in  this  method  there  is  no  allowance 
for  those  seasons  in  which  the  fermenta- 
tion advances  more  rapidly. 

In  general,  the  putrefaction  goes  on 
more  slowly  m  proportion  to  the  fineness 
of  the  rags.  But  when,  on  any  occasion, 
it  advances  more  rapidly  than  the  demand 
from  the  mill,  the  rags  are  turned  over 
and  watered,  to  stop  the  fermentation  and 
prevent  the  bad  effects. 

All  the  inconveniences  attending  the  ex- 
cess of  putrefaction  are  remedied  in  Hol- 
land by  machines  which  triturate  the  rags 
without  having  recourse  to  it ;  and  their 
success  in  this  manner  of  preparing  the 
stuff  has  attracted  the  notice  of  the 
French  artist,  some  of  whom  have  adopt- 
ed with  advantage  the  Dutch  machinery 

Meanwhile,  it  is  possible  to  carry  the 
method  of  putrefaction  to  much  greater 
perfection ;  and  several  manufacturers 
have  made  attempts  so  well  concerted,  as 
to  deserve  the  attention  of  those  who  stu- 
dy the  subject. 

In  the  neighbourhood  of  Brussels  some 
paper-manufacturers,  who  have  construct- 
ed their  mills  after  the  Dutch  plan,  have 
still  found  it  necessary  to  putrefy  their  1 
rags  ;  but,  at  the  same  time,  they  have  an  < 
excellent  method  for  moderating  the  ef-  1 
fects  of  this  putrefaction.    In  the  great  < 
galleries  connected  with  the  buildings  of  i 
the  paper-mill,  they  have  constructed  a  j 
continuation  of  chests,  capable  each  of  i 
them  of  containing  a  certain  quantity  of  J 
rags ;  for  example,  the  quantity  which  1 
the  cylinder  can  triturate  in  one  day.  The  1 
number  of  chests  is  equal  to  the  number  c 
of  days  which  the  rags  in  any  season  re- 
quire for  'putrefaction  ;  and  the  number  c 
actually  employed  is  greater  or  less  ac-  \ 


-  cording  to  the  season.  In  prosecuting  this 

-  plan,  they  lay  a  heap  of  rags  in  one  chest, 
,  as  often  as  they  take  one  from  another, 
>  It  should  also  be  observed,  that,  for  the 
!  sake  of  the  fermentation,  the  rags  are  first 
L  moistened  in  a  large  hollow  stone  before 
■  they  are  arranged  into  the  chests. 

The  peculiar  advantages  ot  this  method 
i  are,  the  equal  fermentation  of  the  rags, 
without  any  part  of  them  being  weaken- 
ed ;  great  ease  in  washing  them  ■  and  it  is 
even  pretended,  that  a  less  degree  of  fer- 
mentation renders  the  impurities  and  the 
discoloured  parts  both  of  hemp  and  linen 
more  soluble,  and  consequently  the  stuff 
of  a  purer  white. 

When  the  rags  are  reduced  to  a  proper 
state  of  putrefaction,  they  are  carried  to 
the  cutting  table,  which  is  placed  on  solid 
tressels,  and  inclosed  on  three  sides  to 
contain  the  rags  cut  on  it,  Before  the  ta- 
ble is  fixed  vertically  a  part  of  the  blade 
of  a  scythe,  the  edge  of  which  is  turned 
from  the  operator.  This  workman,  in  a 
situation  rather  elevated*  takes  from  the 
left  side  a  handful  of  the  putrefied  rags, 
and  arranging  them  the  long  way,  gives 
them  a  gentle  twist,  presses  the  half-form- 
ed rope  against  the  blade  of  the  scythe, 
and,  in  the  manner  of  sawing,  cuts  it  into 
three  or  four  pieces,  which  he  throws  to 
the  right  side  of  the  table.  In  this  opera- 
tion the  rags  lose  part  of  their  filth,  and 
especially  of  the  earthy  particles  occa- 
sioned by  too  much  putrefaction. 

When  the  rags  have  been  submitted  to 
all  the  foregoing  operations,  they  are  in  a 
condition  to  be  reduced  into  a  fibrous  stuff, 
ot  which  the  paper  is  made.  To  obtain 
this  stufrj  mills  are  constructed  on  difier- 
ent  principles.  Those  which  have  been 
used  for  a  long  time  over  all  Europe,  and 
which  by  a  statement  in  the  Encyclopedic 
Methodique,  published  at  Paris  in  1789, 
are  still  used  in  France,  are  mills  with 
mallets.  But  the  mills  invented  by  the 
Dutch,  and  used  in  the  neighbouring  pro- 
vinces, and  excepting  one  instance  in  eve- 
ry part  of  Great  Britain,  are  mills  with  cy- 
linders or  rollers.  In  the  former  ot  these, 
the  mallets  are  raised  by  notches  fixed  at 
convenient  distances  in  a  large  circular 
beam  of  wood.  The  teeth  fixed  on  the 
end  of  the  mallet  fall  into  a  correspond- 
ing gap  made  the  whole  breadth  of  the 
plate,  and  the  strokes  are  repeated  till  the 
rags  are  reduced  lo  a  proper  consistency. 
In  supplying  the  vat  with  water,  and  car- 
rying of  all  the  impurities,  the  operation 
is  nearly  similar  to  that  in  the  nuiis  with 
cylinders. 

Such  is  the  nature  of  what  may  be  call- 
ed the  old  method  of  making  paper.  It 
was  proper  to  speak  of  this  old  method, 


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because  at  one  time,  and  that  not  very  dis- 
tant, it  universally  prevailed.  That  it  was 
inferior  to  that  now  in  practice,  seems  ve- 
ry evident;  and  that  the  rotting  of  the 
rags  was  peculiarly  absurd,  cannot  be  de- 
nied, as  the  paper  made  of  fermented  stuff 
could  neither  be  so  strong  nor  so  durable 
as  that  which  is  made  in  the  common  way 
without  putrefaction. 

The  only  kind  of  paper  that  with  any 
propriety  could  be  made  from  putrefied 
stuffs,  was  paste-board ;  but  we  are  in- 
formed by  the  most  intelligent  paper-ma- 
kers in  Britain,  that  they  seldom  or  never 
even  putrefy  the  rags  or  ropes  of  which 
paste-board  is  made.  It  will  now  be  re- 
quisite to  state  the  method  in  practice  at 
this  time,  with  the  improvements  lately 
made  in  the  art.  And  first  of  the  dus- 
ter. 

The  duster  is  made  in  form  of  a  cylin- 
der, four  and  a  half  feet  in  diameter,  and 
five  feet  in  length.  It  is  altogether  co- 
vered with  a  wire  net,  and  put  in  motion 
by  its  connexion  with  some  part  of  the 
machinery.  A  convenient  quantity  of  the 
rags  after  the  selection  are  enclosed  in 
the  duster,  and  the  rapidity  of  its  motion 
separates  the  dust  from  them,  and  forces 
it  through  the  wire. 

The  selection  is  performed  much  in  the 
same  manner  as  we  have  already  describ- 
ed ;  only  it  is  found  more  convenient  to 
have  the  tables  for  cutting  off  the  knots 
and  stitching,  and  for  forming  them  into 
a  proper  shape,  in  the  same  place  with  the 
cutting  table.  The  surface  both  of  these 
and  of  the  cutting  table  is  composed  of  a 
ware  net,  which  in  every  part  of  the  ope- 
ration allows  the  remaining  dust  and  re- 
fuse of  every  kind  to  escape. 

The  rags,  without  any  kind  of  putre- 
faction, are  again  carried  from  the  cutting 
table  back  to  the  duster,  and  from  thence 
to  the  engine,  where,  in  general,  they  are 
in  the  space  of  six  hours,  reduced  to  the 
stuff  proper  for  making  paper.  The  hard 
and  soft  of  the  same  quality  are  placed  in 
different  lots  ;  but  they  can  be  reduced  to 
stuff  at  the  same  time,  provided  the  soft 
be  put  somewhat  later  into  the  engine. 

The  engine  is  that  part  of  the  mill 
which  performs  the  whole  action  of  reduc- 
ing the  rags  to  paste,  or,  as  it  may  be 
termed,  of  trituration.  The  number  of 
the  engines  depends  on  the  extent  of  the 
paper-work,  on  the  force  of  water,  or  on 
the  construction  of  the  machinery. 

It  requires  great  skill  to  conduct  the 
engine,  whether  it  be  with  regard  to  the 
first  quantity,  to  the  proper  time  for  add- 
ing the  softer  rags,  to  the  augmenting  or 
diminishing  the  water  in  proportion  to  the 

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trituration  ;  or,  finally,  to  knowing  exactly 
when  the  stuff  is  reduced  to  a  proper  con- 
sistency. 

In  the  paper  manufactory  at  Montargis, 
it  was  attempted  to  introduce  rollers  ot 
the  greatest  strength  and  the  least  weight 
possible,  in  order  to  give  them  the  greater 
rapidity  j  but  the  experiment  did  not  suc- 
ceed :  the  rollers  of"  prodigious  rapidity 
were  found  to  produce  stuff  neither  in 
greater  quantity,  nor  of  superior  quality. 
The  most  experienced  artists  have  estab- 
lished a  proportion  between  the  motion  of 
the  roller  and  the  greater  or  less  resist- 
ance of  the  rags.  And  the  Dutch,  who 
have  arrived  at  a  very  great  perfection  in 
this  art,  have  followed  a  method  totally 
different  from  that  practised  at  Montar- 
gis. A  roller  in  Holland,  complete  in  all 
its  parts,  weighs  nearly  30  hundred  weight; 
and  they  find  this  necessary  for  cutting 
the  rags,  especially  if  they  have  not  putre- 
fied. In  proportioning  the  rapidity  to  the 
resistance,  they  have  also  discovered,  that 
a  slow  motion  is  preferable  to  a  rapid  one, 
The  roller  at  Saardom,  by  calculation 
made  from  the  different  parts  of  the  ma- 
chinery, make  about  68  revolutions  in  a 
minute  :  those  at  Montargis  about  166. 
In  Holland,  too,  this  trituration  of  the  rags 
is  divided  into  two  distinct  operations, 
performed  by  rollers  constructed  on  dif- 
ferent principles :  the  first  of  them,  for 
cutting  the  rags  and  preparing  for  the 
other,  is  furnished  with  blades  of  steel 
without  any  moisture,  and  with  a  consi- 
derable space  between  them  ;  the  second, 
intended  to  reduce  the  stuff  to  the  proper 
consistency,  has  a  greater  number  of 
biades,  composed  of  a  mixture  of  brass 
and  copper.  The  mills  with  rollers  are 
in  every  respect  superior  to  those  former- 
ly in  use  with  mallets.  Two  Dutch  roll- 
ers, of  the  construction  we  have  j  ust  now 
described,  will  prepare  as  much  stuff  as 
24  mallets;  they  require  infinitely  less 
room ;  they  do  it  without  putrefaction  ; 
and  as  they  do  it  in  less  time,  and  with 
less  water,  they  occasion  much  less  waste 
of  the  stuff. 

When  the  stuff  is  brought  to  perfection, 
it  is  conveyed  into  a  general  repositoiy, 
which  supplies  the  vat  from  which  the 
sheets  of  paper  are  formed. 

This  vat  is  made  of  wood,  and  gene- 
rally about  five  feet  in  diameter,  and  two 
and  a  half  in  depth.  It  is  kept  in  temper- 
ature by  means  of  a  grate  introduced  by  a 
hole,  and  surrounded  on  the  inside  with 
a  case  of  copper.  For  fuel  to  this  grate, 
they  use  charcoal  or  wood ;  and,  frequent- 
ly, to  prevent  smoke,  the  wall  of  that 
building  comes  in  contact  with  one  part  of 


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the  vat,  and  the  fire  has  no  communica- 
tion with  the  place  where  they  make  the 
paper. 

Every  vat  is  furnished  on  the  upper  part 
with  planks,  enclosed  inwards,  and  even 
railed  in  with  wood,  to  prevent  any  of  the 
stuff  from  running  over  in  the  operation. 
Across  the  vat  is  a  plank  which  they  call 
the  Trapan,  pierced  with  holes  at  one  of 
the  extremities,  and  resting  on  the  planks 
which  surround  the  vat. 

The  forms  or  moulds  are  composed  of 
wire-cloth,  and  a  moveable  frame.  It  is 
with  these  that  they  fetch  up  the  stuff 
from  the  vat,  in  order  to  form  the  sheets 
of  paper  The  sides  of  the  form  are  made 
of  oak,  which  is  previously  steeped  in 
water,  and  otherwise  prepared  to  prevent 
warping1.  The  wire -cloth  is  made  larger 
than  the  sheet  of  paper,  and  the  excess  of 
it  on  all  sides  is  covered  with  a  moveable 
frame.  This  frame  is  necessary  to  retain 
the  stuff  of  which  the  paper  is  made  on 
the  cloth  ;  and  it  must  be  exactly  adapted 
to  the  form,  otherwise  the  edg-es  of  ;he 
paper  will  be  ragged  and  badly  finished. 
The  wire  cloth  of  the  form  is  varied  in 
proportion  to  the  fineness  of  the  paper 
and  the  nature  of  the  stuff 

The  felts  are  pieces  of  woollen  cloth 
spread  over  every  sheet  of  paper,  and  up- 
on which  the  sheets  are  laid,  to  detach 
them  from  the  form,  to  prevent  them  from 
adhering  together,  to  imbibe  part  of  the 
water  with  which  the  stuff  is  charged, 
and  to  transmit  thevvhole  of  it  when  plac- 
ed under  the  action  of  the  press.  The  two 
sides  of  the  felt  are  differently  raised : 
that  of  which  the  hair  is  longest  is  applied 
to  the  sheets  which  are  laid  down ;  and 
any  alteration  of  this  disposition  will  pro- 
duce a  change  in  the  texture  of  the  paper 
The  stuff  of  which  the  felts  are  made 
should  be  sufficiently  strong,  in  order  that 
it  may  be  stretched  exactly  on  the  sheets 
without  forming  into  folds  ;  and,  at  the 
same  time,  sufficiently  pliant  to  yield  in 
every  direction  without  injury  to  the  wet 
paper.  As  the  felts  have  to  resist  the  re- 
iterated efforts  of  the  press,  it  appears 
necessary  that  the  warp  be  very  strong, 
of  combed  wool,  and  well  twisted.  On 
the  other  hand,  as  they  have  to  imbibe  a 
certain  quantity  of  water  and  to  return  it, 
it  is  necessary  that  the  woof  be  of  carded 
wool,  and  drawn  out  into  a  slack  thread. 
These  are  the  utensils,  together  with  the 
press,  which  are  used  in  the  apartment 
where  the  sheets  of  paper  are  formed. 

The  vat  being  furnished  with  a  suffi- 
cient quantity  of  stuff  and  of  water,  two 
instruments  are  employed  to  mix  them ; 
the  one  of  which  is  a  simple  pole,  and  the 
other  a  pole  armed  with  a  piece  of  board, 


rounded  and  full  of  holes.  This  opera- 
tion is  repeated  as  often  as  the  stuff  falls 
to  the  bottom.  In  the  principal  writing 
mills  in  England,  they  use  for  this  pur- 
pose what  is  called  a  hog,  Which  is  a  ma- 
chine within  the  vat,  tnat  by  means  of  a 
small  wheel  on  the  outside,  is  made  to 
turn  constantly  round,  and  keep  the  stuff 
in  perpetual  motion.  When  the  stuff  and 
water  are  properly  mixed,  it  is  easy  to  see 
whether  the  previous  operations  have 
been  complete.  When  the  stuff  floats 
close,  and  in  regular  flakes,  it  is  a  proof 
that  it  has  been  well  triturated  ;  and  the 
parts  of  the  rag  which -have  escaped  the 
rollers  also  appear. 

After  this  operation,  the  workman  takes 
one  of  the  forms,  furnished  with  its  frame, 
by  the  middle  of  the  short  sides,  and  fix- 
ing the  frame  round  the  wire-cloth  with 
his  thumbs,  he  plunges  it  obliquely  four 
or  five  inches  into  the  vat,  beginning  by 
the  long  side,  which  is  nearest  to  him  Af- 
ter the  immersion  he  raises  it  to  a  level : 
by  these  movements  lie  leeches  up  on  ihe 
form  a  sufficient  quantity  of  stuff;  and  as 
soon  as  the  form  is  raised,  the  water 
escapes  through  the  wire  cioth,  and  the 
superfluity  of  the  stuff"  over  the  sides  of 
the  frame.  The  fibrous  parts  of  the  stuff 
arrange  themselves  regularly  on  the  Wire 
cloth  of  the  form,  not  on  I)  in  proportion 
as  the  water  escapes,  but  also  as  the  work- 
man favours  the  effect  by  gently  shaking 
the  form.  Afterwards,  having  placed  the 
form  on  a  piece  of  board,  the  workman 
takes  off  the  frame  or  drckie,  and  glides 
his  form  towards  the  couchers  ;  who,  hav- 
ing previously  laid  his  felt,  places  it  with 
his  left  hand  in  an  inclined  situation,  on  a 
plank  fixed  on  the  edge  of  the  nut,  and 
full  of  holes.  During  this  operation  the 
workman  applies  his  frame,  and  begins  a 
second  sheet.  The  coucher  seizes  this  in- 
stant, takes  with  his  left  hand  the  form, 
now  sufficiently  dry,  and  laying  the  sheet 
of  paper  upon'  the  felt,  returns  the  form 
by  gliding  it  along  the  trapan  of  the  vat. 

They  proceed  in  this  manner,  laying  al- 
ternately a  sheet  and  a  felt,  till  they  have 
made  six  quires  of  paper,  which  is  called 
a  post ;  and  this  they  do  with  such  swift- 
ness, that,  in  many  sorts  of  paper,  two 
men  make  upwards  of  20  posts  in  a  day. 
When  the  last  sheet  of  the  post  is  cover- 
ed with  the  last  felt,  the  workmen  about 
the  vat  unite  together,  and  submit  the 
whole  heap  to  the  action  of  the  press. 
They  begin  at  first  to  press  it  with  a  mid- 
dling- lever,  and  afterwards  with  a  lever 
of  about  fifteen  feet  in  length.  After  this 
operation,  another  person  separates  the 
sheets  of  paper  from  the  felts,  laying  them 
in  a  heap ;  and  several  of  these  heaps  col 


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lected  tog-ether  are  again  put  under  the 

press. 

Tlie  stuff  which  forms  a  sheet  of  pa- 
per is  received,  us  we  have  already  said, 
on  a  form  made  of  wire  cloth,  which  is 
more  or  less  fine  in  proportion  to  the  stuff, 
and  surrounded  with  a  wooden  frame,  and 
supported  in  the  middle  by  many  cross 
bars  of  wood.  In  consequence  of  this 
construction,  it  is  easy  to  perceive,  that 
the  sheet  of  paper  will  take  and  preserve 
the  impressions  of  all  the  pieces  which 
compose  the  form,  and  of  the  empty 
spaces  between  them. 

The  traces  of  the  wire-cloth  are  evi 
dently  perceived  on  the  side  of  the  sheet 
which  was  attached  to  the  form,  and  on 
the  opposite  side  they  form  an  assemblage 
of  parallel  and  rounded  risings.  As  in  a 
paper  which  is  most  highly  finished,  the 
regularity  of  these  impressions  is  still  vi- 
sible, it  is  evident  that  ali  the  operations 
to  which  it  is  submitted  have  chiefly  in 
view  to  soften  these  impressions  without 
destroying  them.  It  is  of  consequence, 
therefore,  to  attend  to  the  combination  of 
labour  which  operates  on  these  impres- 
sions. The  coucher,  in  turning  the  form 
on  t!te  felt,  flattens  a  little  the  rounded 
eminences  which  are  in  relievo  on  one  of 
the  surfaces,  and  occasions  at  the  same 
time  the  hollow  places  made  by  the  wire- 
cloth  to  be  partly  filled  up.  Meanwhile, 
the  effort  which  is  made  in  detaching  a 
form,  produces  an  infinite  number  of  small 
hairs  in  every  protuberant  part  of  the 
sheet. 

Under  the  action  of  the  press,  first  with 
the  felts,  and  then  without  them,  the  per- 
fecting of  the  grain  of  paper  still  goes  on 
The  vestiges  of  the  protuberances  made 
by  the  wire  are  altogether  flattened,  and  j 
of  consequence  the  hollow  s  opposite  to  ; 
them  disappear  also  ;  but  the  traces  form- 
ed by  the  interstices  of  the  wire,  in  conse- ' 
quence  of  their  thickness,  appear  on  both 
sides,  and  are  rounded  by  the  press 

The  risings  traced  on  each  side  of  the 
paper,  and  which  can  be  discovered  by  the 
eye  on  that  which  is  most  highly  finished, 
form  what  is  called  the  grain  paper.  The 
different  operations  ought  to  soften,  but 
not  destroy  it;  which  is  effectually  done 
by  employing  the  hammer.  This  grain 
appears  in  the  Dutch  paper  ;  which  is  a 
sufficient  proof,  that  though  they  have 
brought  this  part  of  the  art  to  the  great- 
est perfection,  they  have  not  employed 
hammers,  but  more  simple  and  ingenious 
means.  The  grain  of  paper  is  often  disfi- 
gured by  the  felts  when  they  are  too  much 
used,  or  when  the  wool  does  not  cover 
the  thread.  In  this  case,  when  the  paper 
is  submitted  to  the  press,  it  takes  the  ad- 


ditional traces  of  the  warp  and  woof,  and 
composes  a  surface  extremely  irregular. 

The  paper,  the  grain  ot  which  is  highly 
softened,  is  much  fitter  for  the  purposes 
of  writing  than  that  w  inch  is  smoothed 
by  the  hammer:  on  the  other  hand,  a 
coarse  and  unequal  grain  very  much  op- 
poses the  movements  of  the  pen;  as  that 
which  is  beaten  renders  them  very  uncer- 
tain The  art  of  making  paper,  therefore, 
should  consist  in  preserving,  and  at  the 
Same  time  in  highly  softening,  the  grain  : 
the  Dutch  have  carried  this  to  the  high- 
est perfection. 

The  exchange  succeeds  the  operation 
last  described.  It  is  conducted  in  a  hall 
contiguous  to  the  vat,  supplied  with  seve- 
ral presses,  and  with  a  long  table.  The 
workman  arranges  on  this  table  the  paper 
newh'  fabricated  into  heaps ;  each  heap 
containing  eight  or  ten  of  these  last  under 
the  press,  kept  separate  by  a  woollen  felt. 
The  press  is  large  enough  to  receive  two 
of  them  at  once,  placed  the  one  at  the  side 
of  tiie  other.  When  the  compression  is 
judged  sufficient,  the  heaps  of  paper  are 
carried  back  to  the  table,  and  the  whole 
turned  sheet  by  sheet,  in  such  a  manner 
that  the  surface  of  every  sheet  is  exposed 
to  a  new  one ;  and  in  this  situation  they 
are  again  brought  under  the  press.  It  is 
in  conducting  these  operations  sometimes 
to  four  or  five  times,  or  as  often  as  the  na- 
ture of  the  paper  requires,  that  the  perfec- 
tion of  the  Dutch  plan  consists.  If  the 
stuff  be  fine,  or  the  paper  slender,  the 
exchange  is  less  frequently  repeated-  In 
this  operation  it  is  necessary  to  alter  the 
situation  of  the  heaps,  with  regard  to  one 
another,  every  time  they  are  put  under 
the  press  ;  and  also,  as  the  heaps  are 
highest  toward  the  middle,  to  place  small 
pieces  of  felt  at  the  extremities,  in  order 
to  bring  every  part  of  them  under  an 
equal  pressure.  A  single  man  with  lour 
or  five  presses  may  exchange  all  the  pa- 
per produced  by  two  vats,  provided  the 
previous  pressing  at  the  vats  be  well  per- 
formed. The  work  of  the  exchange  ge- 
nerally lasts  about  two  days  on  a  given 
quantity  of  paper. 

When  the  paper  has  undergone  these 
operations,  it  is  not  only  softened  in  the 
surface,  but  better  felted,  and  rendered 
more  pliant  in  the  anterior  parts  of  the 
stuff.  In  short,  a  great  part  of  the  water 
which  it  had  imbibed  in  the  operations  of 
the  vat  is  dissipated  By  the  felting  of  pa- 
per is  understood  the  approximation  of 
the  fibres  of  the  stuff,  and  their  adhering 
more  closely  together.  The  paper  is  felt- 
ed in  proportion  as  the  water  escapes ; 
and  this  tffect  is  produced  by  the  ma- 
nagement and  reiterated  action  of  the 


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press.  Were  it  not  for  the  gradual  ope- 
ration of  the  press,  the  paper  would  be 
porous,  and  composed  of  filaments  adher- 
ing- closely  together.  The  superiority  of 
the  Dutch  over  the  French  paper  depends 
almost  entirely  on  this  operation. 

If  the  sheets  of  paper  are  found  to  ad- 
here together,  it  is  a  proof  that  the  busi- 
ness of  the  press  has  been  badly  conduct- 
ed. To  avoid  this  inconvenience,  it  is  ne- 
cessary to  bring  down  the  press  at  first 
gently,  and  by  degrees  with  greater  force, 
and  "to  raise  it  as  suddenly  as  possible. 
By  this  means  the  water,  which  is  impell- 
ed to  the  sides  of  the  heaps,  and  which 
has  not  escaped,  turns  to  the  centre  ;  the 
sheets  are  equally  dry,  and  the  operation 
executed  without  difficulty 

According  to  the  state  of  dryness  in 
which  the  paper  is  found  when  it  comes 
from  the  apartment  of  the  vat,  it  is  either 
pressed  before  or  after  the  fu  st  exchange 
The  operation  of  the  press  should  be  reite- 
rated and  managed  with  great  care ; 
otherwise  in  the  soft  state  of  the  paper, 
there  is  a  danger  that  its  grain  and  trans- 
parency be  totally  destroyed.  Another 
essential  principle  to  the  success  of  the 
exchange  is,  that  the  grain  of  the  paper 
be  originally  well  raised  For  this  pur- 
pose, the  wire-cloth  of  the  Dutch  forms,  is 
composed  of  a  rounder  wire  than  those 
used  in  France,  by  which  they  gain  the 
greatest  degree  of  transparency,  and  are 
in  no  danger  of  destroying  the  grain.  Be- 
sides this,  the  Dutch  take  care  to  propor- 
tion the  wires,  even  where  the  forms  are 
even  to  the  thickness  of  the  paper. 

Almost  every  kind  of  paper  is  consider- 
ably improved  by  the  exchange,  and  re- 
ceives a  degree  of  perfection  which  ren- 
ders it  more  agreeable  in  the  use.  But 
it  is  necessary  to  observe  at  the  same 
time,  that  all  papers  are  not  susceptible 
of  this  melioration ;  on  the  contrary,  if 
the  stuff  be  unequal,  dry,  or  weakened  by 
the  destruction  of  the  fine  parts,  it  ac- 
quires nothing  of  that  lustre  and  softness, 
and  appearance  of  velvet,  which  the  ex- 
change gives  to  stuff  properly  prepared: 

The  sheds  for  drying  the  paper  are  in 
the  neighbourhood  of  the  paper-mill,  and 
are  furnished  with  a  vast  number  of  cords, 
on  which  they  hang  the  sheets  both  before 
and  after  the  sizing.  The  sheds  are  sur- 
rounded with  moveable  lattices,  to  admit 
a  quantity  of  air  sufficiently  for  drying  the 
paper.  The  cords  of  the  shed  are  stretch- 
ed as  much  as  possible ;  and  the  paper, 
four  or  five  sheets  of  it  together,  is  plac- 
ed on  them  by  means  of  a  small  wooden 
instrument  in  the  shape  of  a  pick-axe. 

The  principal  difficulty  in  drying  the 
paper,  consists  in  gradually  admitting  the 


external  air,  and  in  preventing  the  cords 
from  imbibing  moisture.  With  regard  to 
the  first  of  these,  the  Dutch  use  very  low 
sheds,  and  construct  their  lattices  with 
great  exactness.  By  this  means  the  Dutch 
paper  is  dried  equally,  and  is  extremely 
supple  before  the  sizing.  They  prevent 
the  cords  from  imbibing  the  water  by  co- 
vering them  with  wax.  In  using  such 
cords,  the  moisture  does  not  continue  in 
the  line  of  contact  between  the  paper  and 
the  cord,  which  prevents  the  sheet  from 
stretching  in  that  particular  place  by  its 
weight,  and  from  the  folds  which  the 
moisture  in  the  subsequent  operations 
might  occasion.  The  Dutch  also  employ 
cords  of  considerable  thickness,  and  place 
fewer  of  them  under  the  sheets  ;  by  which 
means  they  diminish  the  points  of  con- 
tact, and  give  a  freer  and  more  equal  cir- 
culation to  the  air. 

The  size  for  paper  is  made  of  the 
shreds  and  pareings  got  from  the  tanners, 
curriers,  and  parchment  makers.  All  the 
putrefied  parts  and  the  lime  are  carefully 
separated  from  them,  and  they  are  en- 
closed into  a  kind  of  basket,  and  let  down 
by  a  rope  and  pulley  into  the  cauldron. 
This  is  a  late  invention,  and  serves  two 
valuable  purposes.  It  makes  it  easy  to 
draw  out  the  pieces  of  leather  when  the 
size  is  extracted  from  them  by  boiling,  or 
easy  to  return  them  into  the  boiler,  if  the 
operation  be  not  complete  When  the 
substance  is  sufficiently  extracted,  it  is 
allowed  to  settle  for  some  time;  and  it  is 
twice  feltered  before  it  is  put  into  the  ves- 
sel into  which  they  dip  the  paper. 

Immediately  before  the  operation,  a  cer- 
tain quantity  of  allum  is  added  to  the 
size.  The  workman  takes  a  handful  of 
sheets,  smoothed  and  rendered  as  supple 
as  possible,  in  his  left  hand,  dips  them  into 
the  vessel,  and  holds  them  separate  with 
his  right,  that  they  may  equally  imbibe 
the  size.  After  holding  them  above  the 
vessel  for  a  short  space  of  time,  he  seizes 
on  the  other  side  with  his  right  hand,  and 
again  dips  them  into  the  vessel.  When 
he  has  finished  ten  or  a  dozen  of  these 
handfuls,  they  are  submitted  to  the  action 
of  the  press.  The  superfluous  size  is 
carried  back  to  the  vessel  by  means  of  a 
small  pipe.  The  vessel  in  which  the  pa- 
per is  sized  is  made  of  copper,  and  fur- 
nished with  a  grate,  to  give  the  size,  when 
necessary,  a  due  temperature;  and  a 
piece  of  thin  board  or  felt  is  placed  be- 
tween every  handful  as  they  are  laid  on 
the  table  of  the  press. 

The  Dutch  are  very  careful,  in  sizing 
their  paper,  to  have  every  sheet  in  the 
same  handful  of  the  same  dryness ;  be- 
cause it  is  found  that  the  dry  sheets  im- 


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hi  be  the  size  more  slowly  than  those  which 
retain  some  degree  of  moisture.  They 
begin  by  selecting  the  packs  in  the  dry- 
ing-house; and  after  having  made  them 
supple,  and  having  destroyed  the  adher- 
ence between  the  sheets,  they  separate 
them  into  handfiils  in  proportion  to  the 
dryness,  eacli  of  them  containing  that 
number  which  they  can  dip  at  one  time. 
Besides  this  precaution,  they  take  care  to 
apply  two  sheets  of  brown  paper  of  an 
equal  size  to  every  handful.  This  brown 
paper,  firm,  solid,  and  already  sized,  is  of 
use  to  support  the  sheets. 

As  soon  as  the  paper  is  sized,  it  is  the 
practice  of  some  paper-mills  to  carry  it 
immediately  to  the  drying-house,  and 
hang  it  before  it  cools  sheet  by  sheet  on 
the  cords.  The  paper,  unless  particular 
attention  be  paid  to  the  lattices  of  the 
drying-house,  is  apt  to  dry  too  fast, 
whereby  a  great  part  of  the  size  goes  off 
by  evaporation;  or,  if  too  slow,  it  falls  to 
the  ground.  The  Dutch  drying-houses 
are  the  best  to  prevent  these  inconvenien- 
ces :  but  the  exchange  after  the  sizing, 
which  is  generally  practised  in  Holland, 
is  the  best  remedy  They  begin  this  ope- 
ration on  the  handfuls  of  paper,  either 
while  they  are  still  hot,  or  otherwise,  as 
they  find  it  convenient.  But,  after  the  ex- 
change, they  are  careful  to  allow  the  heaps 
to  be  altogether  cold  before  they  are  sub- 
mitted to  the  press.  Without  this  precau- 
tion, the  size  would  be  either  wholly 
squeezed  out  by  the  press  of  the  ex- 
change, or  the  surface  of  the  paper  be- 
come very  irregular.  It  is  of  consequence 
that  the  paper,  still  warm  from  the  sizing, 
grow  gradually  firm,  under  the  operation 
of  the  exchange,  in  proportion  as  it  cools. 
By  this  method  it  receives  that  varnish 
which  is  afterwards  brought  to  perfection 
under  the  press,  and  in  which  the  excel- 
lency of  the  paper,  either  for  writing  or 
drawing,  chiefly  consists.  It  is  in  conse- 
quence of  the  exchanging  and  pressing, 
that  the  Dutch  paper  is  soft  and  equal, 
and  that  the  size  penetrates  into  the  body 
of  it,  and  is  extended  equally  over  its 
surface. 

The  exchange,  after  the  sizing,  ought 
to  be  conducted  with  the  greatest  skill 
and  attention,  because  the  grain  of  the  pa- 
per then  receives  impressions,  which  can 
never  be  eradicated.  When  the  sized 
paper  is  also  exchanged,  it  is  possible  to 
hang  more  sheets  together  on  the  cords  of 
the  drying-house.  Paper  dries  better  in 
this  condition,  and  the  size  is  preserved 
without  any  sensible  waste,  because  the 
sheets  of  paper  mutually  prevent  the  ra- 
pid operation  of  the  external  air.  And  as 
the,  size  has  already  penetrated  into  the 


paper,  and  is  fixed  on  the  surface,  the  in- 
sensible progress  of  a  well  conducted 
drying-house  renders  all  the  good  effect* 
more  perfect  in  proportion  as  it  is  slowly 
dried. 

If  to  these  considerations  be  added  the 
damage  done  to  the  paper  in  drying  it  im- 
mediately after  the  press  of  the  sizing 
room,  whether  it  be  done  in  raising  the 
hairs  by  separating  the  sheets,  or  in  crack- 
ing  the  surface,  it  is  evident  that  the  trou- 
ble of  the  second  exchange  is  infinitely 
overpaid  by  the  advantage. 

When  the  paper  is  sufficiently  dry,  it  is 
carried  to  the  finishing  room,  where  it  is 
pressed,  selected,  examined,  folded,  made 
up  into  quires,  and  finally  into  reams.  It 
is  here  put  twice  under  the  press  ;  first, 
when  it  is  at  its  full  size,  and,  secondly,  af- 
ter it  is  foided  The  principal  labour  of 
this  plan  consists  in  assorting  the  paper 
into  different  lots,  according  to  its  quality 
and  faults  ;  after  which  it  is  made  up  into 
quires.  The  person  who  does  this  must 
possess  great  skill,  and  be  capable  of 
great  attention,  because  he  acts  as  a  check 
on  those  who  separated  the  paper  into 
different  lots.  He  takes  the  sheets  with 
his  right  hand,  folds  them,  examines 
them,  lays  them  over  his  left  arm,  till  he 
has  the  number  requisite  for  a  quire, 
brings  the  sides  parallel  to  one  another, 
and  places  them  in  heaps  under  the  table. 
An  expert  workman,  if  proper  care  has 
been  taken  in  assorting  the  lots,  will  finish 
in  this  manner  near  six  hundred  quires  in 
a  day. 

The  paper  is  afterwards  collected  into 
reams  of  20  quires  each,  and  for  the  last 
time  put  under  the  press,  where  it  is  con- 
tinued ten  or  twelve  hours,  or  as  long  as 
the  demand  for  paper  at  the  paper-mill 
will  permit. 

A  method  has  lately  been  discovered  of 
bleaching  the  rags  or  stuff,  which  will  un- 
doubtedly be  adopted  every  where,  in  the 
preparation  of  writing  paper,  provided  the 
expense  of  the  process  be  not  too  great. 
This  discovery  was  made  by  Scheele,  M. 
Berthollet,  and  M.  Chaptal.  The  first  of 
these  illustrious  writers,  communicated  to 
the  Swedish  academy  of  sciences,  an  es- 
say on  Manganese,  containing  a  numerous 
series  of  experiments,  intended  to  inves- 
tigate the  nature  and  properties  of  that 
substance.  Among  these  experiments, 
were  several  which  pointed  out  a  new  state 
of  the  muriatic  acid,  or  the  acid  distilled, 
from  sea-salt. 

This  state  of  the  muriatic  acid,  was 
produced  by  M.  Scheele,  in  consequence 
of  putting  the  said  acid  into  a  retort,  or 
distilling  vessel,  along  with  the  manga- 
nese, and  distilling  over  the  acid  into  a 


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propei*  receiver;  it  was  found  to  have 
changed  iis  nature  and  properties,  in  a 
very  remarkable  manner, while  at  the  same 
time  the  manganese  remaining  in  the  re- 
tort, had  suffered  a  ve~y  material  altera 
tion. 

To  the  new  state  of  the  acid  thus  pro- 
duced, m  consequence  of  certain  theoretic 
ideas,  which  M.  Scheele  entertained,  res- 
pecting the  mutual  action  of  the  original 
muriatic  acid,  and  the  manganese  on  each 
other,  during  the  process  of  distillation, 
he  gave  the  name  of  Dephlogisticated  JMu- 
riutic  Acid  Since  the  time  of  this  origi- 
nal discovers  ,  in  consequence  of  certain 
changes,  which  had  occurred,  in  the  the- 
ory or  philosophy  of  chemistry,  this  new 
state  of  the  acid  of  sea-salt,  has  been  call- 
ed, the  Ox  igenattd  Muriatic  Acid.  Among 
man;,  other  properties  of  it,  discovered  by 
Mr  Scheele,  the  most  remarkable  was, 
that  it  destroyed  the  colour  of  every  vege- 
table substance,  which  was  exposed  to 
its  action  ;  or,  in  other  words,  it  bleached 
them  :  or,  in  the  language  of  the  dyers,  it 
discharged  their  colours  ;  that  is  to  say, 
whatever  happened  to  be  the  colour  or 
any  vegetable  body,  that  was  submitted 
to  the  action  of  the  above  acid,  it  always 
became  white,  or  lost  its  colouring  mat- 
ter. 

In  the  year  1786,  Dr.  Bedoes,  professor 
of  chemistry,  in  the  university  of  Oxford, 
(England )  published  an  English  transla- 
tion of  the  Chemical  Essays  of  Mr.Scheele; 
and  thereby  made  known  to  the  chemists 
of  Great  Britain,  the  power  of  the  oxyge- 
nated muriatic  acid;  to  bleach  or  whiten 
vegetable  substances,  or  to  discharge  or 
decompose  their  colour.  But  M.  Berthol- 
let,  a  celebrated  French  chemist,  and  one 
of  the  members  of  the  Academy  of  Scien- 
ces at  Paris,  appears  to  have  been  the  first, 
who  thought  of  rendering  the  above  re- 
cited discovery,  subservient  to  the  pur- 
poses of  manufacture. 

In  1789,  he  published  in  the  Annates  de 
Chimie  an  essay  calculated  entirely,  for 
the  use  of  manufacturers,  by  being  divest- 
ed of  theoretic  discussions  ;  of  which  the 
title  is,  "  Method  of  bleaching  linen  or 
cotton  cloths,  threads  and  yarns,  by  means 
of  oxygenated  muriatic  acid,  and  of  some 
other  properties,  which  may  be  useful  to 
manufactures. ' 

In  the  same  work,  and  in  the  same  year, 
M.  Chaptal,  another  French  chemist,  pub- 
lished an  account  of  some  experiments, 
in  which,  among  many  other  applications, 
of  the  oxygenated  muriatic  acid,  to  pur- 
poses useful  in  the  (Economical  arts,  he 
gives  information  of  having  bleached  or 
whitened  coarse  rags,  used  by  the  paper 
makers,  so  as  greatly  to  improve  the  qua- 


lity of  the  paper,  into  which  they  were 
afterwards  manufactured     His  prepara- 
tion of  tiiis  bleaching  liquor,  differs  not 
from  Berthoilet's,  which  is  as  follows  : 
"  Take  six  ounces  of  manganese,  and  16 
ounces  of  sea-sait,  both  reduced  to  a  fine 
powder ;  mix  these  accurately,  and  intro- 
duce them  into  a  retort  or  distilling  ves- 
sel :  then  take  12  ounces  of  oh  of  vitriol, 
and  eight  ounces  of  water,  mixed  toge- 
ther and  allowed  to  cool ;  add  tliese  to 
( the  other  ingredients  in  the  retort,  and 
j  connect  the  retort  with  a  cask  or  receiv  er, 
I  capable  of  holding  27 1  gallons  ol  water, 
j  but  only  containing  25  gallons,  which  is 
I  to  be  impregnated  with  the  gas  or  vapour, 
j  of  the  oxygenated  muriatic  acid ;  and  pro- 
iceed  10  distillation,  first  without  and  af- 
jterwards  with  a  fire  gradually  raised,  till 
ithe  whole  acid  com  s  over." 

Experiments  have  been  made  with  this 
j  liquor,  both  by  some  of  the  principal  pa- 
I  per  makers, in  the  neighbourhood  of  Edin- 
I  burgh,and  by  Messrs  Clement  and  George 
Taylors,  of  Maidstone  in  Kent.  By  the 
former  it  was  found,  that  paper  made  of 
rags  and  pulp  whitened  in  this  manner, 
was  supenour  to  any  other  made  of  simi- 
lar materials,  not  only  in  colour,  but  in 
fineness  of  texture.  By  the  latter,  the  ex- 
cellence of  the  liquor  was  found  to  be  so 
great,  that  probably  having  never  heard 
of  Scheele,  Berthoilet,  and  Chaptal,  and 
conceiving  themselves  to  be  the  first  in- 
ventors of  it,  they  obtained  a  patent  for  its 
exclusive  use,  which  other  manufactu- 
rers will  doubtless  disregard.  It  is  not 
to  be  concealed,  however,  that  even  with 
all  the  precautions  which  can  possibly  be 
taken  at  first,  various  circumstances  of  im- 
perfection, must  necessarily  remain  to  be 
removed,  by  means  of  farther  experience, 
both  in  the  perfection  of  the  bleaching 
process,  and  the  oeconomy  of  its  applica- 
tion to  use  ;  but  for  the  attaining  of  this 
experience,  a  short  time  will  rarely  be 
sufficient.    See  Bleaching. 

Section  II. 

Of  the  different  kinds  of  Paper. 
The  paper  proper  for  writing,  should 
be  without  knots,  without  any  parts  of  the 
stuff  not  triturated,  without  folds,  and 
without  wrinkles,  softened  in  the  ex- 
change, and  not  destroyed  by  smoothing. 
The  ground  of  this  paper  must  be  ex- 
tremely white,  or  shaded  with  a  very  light 
blue,  which  adds  to  its  natural  splendor. 
It  is  of  great  importance  that  it  be  fully 
and  equally  sized,  otherwise  the  writing 
cannot  be  well  finished,  and  the  turnings 
of  the  leUers  will  be  very  imperfect.  This 
paper  should  be  made  from  stuff  not  pu- 


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tre.fied,which  takes  a  better  grain,  receives 
more  benefit  from  the  exchange,  is  more 
equally  sized,  and  finally,  is  less  subject 
to  folds  and  wrinkles,  in  the  different  ope- 
rations. To  make  paper  peculiarly  fit  for 
durable  writing,  Dr.  Lewis  recommends 
the  impregnation  of  it  with  astringent  ma- 
terials. '  It  is  observable  (says  he,)  that 
writings  first  begin  to  fade,  or  change 
their  colour,  on  the  back  of  the  paper, 
where  I  He  larger  strokes  have  sunk  in,  or 
are  visibie  through  it;  as  if  part  of  the 
irony  matter  of  the  vitriol,  was  in  a  more 
subtile  or  dissolved  state  than  the  rest, 
and  sunk  further,  on  account  of  its  not 
being  fully  disengaged  from  the  acid,  or 
sufficiently  combined  with  the  astringent 
matter,  of  the  galls  Hence,  it  should 
seem  probable,  that  if  the  paper  was  im- 
pregnated with  astringent  matter,  the  co- 
lour of  the  ink  would  be  more  durable. 
To  see  how  far  this  notion  was  well  found- 
ed, I  dipt  some  paper  in  an  infusion  of 
galls  ;  and,  when  dry,  repeated  the  dip- 
ping a  second  and  third  time.  On  the 
paper  thus  prepared,  and  some  that  was 
unprepared,  I  wrote  with  different  inks; 
several  of  which,  that  the  effects  might 
be  more  sensible,  has  an  over  proportion 
of  vitriol.  The  writings  being  exposed  to 
the  weather,  till  the  best  of  the  inks  on 
the  unprepared  paper,  had  faded  and 
changed  their  colour,  those  on  the  prepar- 
ed paper,  were  ail  found  to  retain  their 
blackness.  It  is  therefore  recommended 
to  the  consideration  of  paper  makers,  whe- 
ther a  particular  kind  of  paper,  might  not 
be  prepared  for  Uiose  uses,  where  the 
long  duration  of  the  writing,  is  of  princi- 
pal impo  tance,  by  impregnating  it  with 
gabs  or  other  astringents,  in  some  of  the 
operations  it  passes  through,  before  it  re- 
ceives the  glazing ;  as  for  instance,  by 
using  an  astringent  infusion,  instead  of 
common  water,  in  ihelast  operation,  when 
the  matter  is  reduced  into  a  pulp,  for 
being  formed  into  sheets.  The  brownish 
hue,  which  the  paper  receives  from  the 
galling,  would  not  perhaps,  be  any  great 
obstacle  to  its  use ;  and,  if  the  proposal 
should  be  thought  worthy  of  being  car- 
ried into  execution,  further  inquiries  may 
possibly  discover  the  means,  of  obviating 
the  imperfection,  and  communicating  as- 
tringency  without  colour  " 

The  paper  used  for  drawing,  or  for  co- 
loured maps,  is  in  some  mills,  made  from 
one  kind  of  white  stuff,  either  fine  or  mid- 
dling; in  others  from  a  mixture  of  three 
or  four  kinds  of  stuff,  of  different  colours. 
The  Dutch  were  not  long  ago  almost 
wholly  in  possession  of  this  manufacture. 
The  same  qualities  are  necessary  in  this 


paper,  as  in  that  for  writing.  The  grain, 
however,  must  be  a  little  more  raised,  al- 
though softened  by  the  exchange;  for, 
without  this  grain,  the  pencil  would  leave 
with  difficulty,  the  traces  of  the  objects. 
Great  care  is  also  necessary,  in  the  sizing 
of  this  paper,  that  the  drawing  be  neatly 
performed,  and  also  that  the  sinking  of 
the  ink  or  colours,  into  the  irregularities 
of  the  stuff  be  prevented. 

This  paper  is  also  made  in  great  per- 
fection, by  stuffs  not  rotted.  These  take 
a  more  even  gloss,  and  are  in  better  con- 
dition, to  receive  all  the  impressions  of 
the  painter.  It  is  also  necessary  that  fur- 
niture paper,  be  well  softened,  and  sub- 
mitted to  the  exchange,  to  take  more  ex- 
actly, the  outlines  of  the  figures.  The 
French  have  carried  this  part  of  the  ma- 
nufacture of  paper,  to  the  highest  state  of 
perfection. 

The  British  and  Dutch,  have  had  the 
greatest  success  in  manufacturing  paste- 
board, which  they  make  either  from  a 
single  mass  of  stuff  on  the  form,  or  from 
a  collection  of  several  sheets  pasted  to- 
gether. In  both  cases,  the  sheets  of  paste- 
board, are  made  of  stuff  not  rotted,  and 
triturated  with  rollers,  furnished  with 
blades  of  well  tempered  steel.  By  the 
operation  of  the  exchange,  and  smoothing 
continued  for  a  long  time,  the  British  and 
Dutch,  obiain  solid  and  smooth  stuffs, 
which  neither  break  under  the  folds  of 
cloth,  nor  adhere  to  them  The  stuffs 
not  putrefied,  have  another  ad*  antage  in 
this  species  of  pasteboard,  namely,  tha\  of 
resisting  the  action  of  heat,  which  they 
experience  between  the  folds  of  cloth, 
without  wasting  or  tarnishing,  and  of  con- 
sequence they  may  be  used  for  a  long- 
time. & 
In  England  they  have  at  least  equalled 
any  other  nation,  in  the  manufacture  of 
this  paper ;  and  even  in  Scotland,  they 
have  arrived  to  such  a  degree  of  perfec- 
tion in  this  art,  that  great  part  of  what 
they  manufacture  is  sent  to  England.  It 
requires  to  be  made  of  a  soft  and  equal 
stuff,  without  folds  or  wrinkles,  of  a  na- 
tural whiteness,  and  with  a  shade  of  blue. 
It  must  be  sized  less  strongly  than  writ- 
ing paper,  but  sufficiently  well  to  give 
neatness  to  the  characters]  This  paper, 
thus  properly  prepared,  yields  easily  to 
the  printing  press,  and  t:ikes  a  sufficient 
quantity  of  ink.  The  stuff  must  be  with- 
out grease,  and  wrought  with  that  degree 
of  slowness,  as  to  make  it  spread  equally 
over  the  form,  and  take  a  neat  and  regu. 
lar  e:rain;  without  this  'he  characters  will 
not  be  equally  marked  in  every  part  of  the 
page  :  and  the  smallest  quantity  of  grease 


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venders  the  sizing-,  unequal  and  imper- 
fect. Some  artists  with  considerable  suc- 
cess, both  to  meliorate  the  grain,  and  to 
reduce  the  inequalities  of  the  surface, 
have  submitted  this  paper  to  the  exchange. 
And  it  is  proper  to  add,  that  a  moderate 
degree  of  exchanging,  and  of  pressing, 


Section  HI. 

Misellaneous  Observations  on  Paper. 
To  hinder  paper  from  sinking,  take 
about  the  size  of  a  nut  of  rock  alum,  dis- 
solve it  in  a  glass  of  clear  water,  and  ap- 
ply it  to  the  paper,  which  has  not  been 


may  be  of  great  service,  after  the  sheets  J  sufficiently  sized,  with  a  fine  sponge  It 
are  printed,  to  destroy  the  hollow  places  •  is  in  this  manner,  that  the  paper  manufac- 
occasioned  by  the  press,  and  the  relievo  of  j  turers  of  Paris,  prepare  the  paper  for 
the  letters 

Engraving  requires  a  paper  of  the  same 
qualites,  with  the  last  mentioned,  with  re- 
spect to  the  stuff,  which  must  be  pure 
without  knots,  and  equally  reduced ;  the 
grain  uniform,  and  the  sheets  without 
folds  or  wrinkles.  To  preserve  the  grain, 
it  is  necessary  that  it  be  dried  slowly,  in 
the  lowest  place  of  the  drying-house.  If 
it  is  submitted  to  the  exchange,  the  effects 


of  it  must  be  moderated  with  the  greatest 
care,  and  the  action  of  the  two  first  press- 
es, must  be  equally  distributed  over  the 
whole  mass,  otherwise  the  inequality  of 
the  moisture  at  the  middle  and  sides,  will 
expose  it  to  the  wrinkles  in  the  drying. 
The  sizing  of  this  paper,  must  also  be  mo- 
derate. These  circumstances,  are  neces- 
sary to  make  it  receive  with  neatness,  all 
the  soft  and  delicate  touches  of  the  plate. 
The  soft  and  yielding  paper  of  Auvergne, 
possesses  all  those  advantages ;  and  ac- 
cordingly, a  great  quantity  of  this,  and  of 
formerly  imported 


drawing,  called papiers  laves.  When  there 
is  occasion  to  write  on  a  printed  book,  or 
on  paper  too  fresh,  it  is  sufficient  to  mix 
a  little  gum  with  ordinary  ink. 

To  give  to  writing  paper  a  brilliant  var- 
nish, take  that  which  is  of  an  ordinary 
fineness,  very  smooth,  without  any  kind 
of  stain  or  hairs  on  its  surface ;  stretch  it 
on  a  smooth  plank,  and  by  means  of  a 
hare's  foot  cover  it  with  a  thin  and  equal 
layer  of  sandarac  finely  powdered.  Af- 
terwards, if  a  whole  ream  is  to  be  var- 
nished, take  eight  ounces  of  rock  alum 
and  one  ounce  of  white  sugar-candy  5 
bring  them  to  boil  in  six  pints  of  water; 
and  when  the  liquor  is  lukewarm,  wet 
that  side  of  the  sheet  which  has  been 
covered  with  the  sandarac  with  a  fine 
sponge;  lay  the  sheets  in  a  heap,  one 
sheet  exactly  above  another;  and  submit 
the  ream  to  the  press  for  the  space  of 
twelve  hours :  hang  them  afterwards, 
sheet  by  sheet,  on  the  cords  of  the  drying 
house ;  put  them  again  under  the  press 


printing  paper,  were  iorme 

into  Britain  and  Holland  from  France,  I  for  some  days  to  stretch  them  ;  and  final- 
where  they  still  continue  to  rot  the  mate- 1  ly,  beat  them  with  a  bookbinder's  mallet 
rial,  from  which  they  make  engraving  pa-  j  This  paper  can  only  be  used  for  three  or 
per-    The  wire  wove  frame,  though  but  j  four  months  after  it  is  prepared. 


lately  invented,  is,  we  are  told,  peculiarly 
adapted  to  this  kind  of  paper. 

Paper  for  cards  must  be  manufactured 
ii'om  a  pretty  firm  stuff,  in  order  to  take 
that  degree  of  smoothness,  which  makes 
the  cards,  glide  easily  over  one  another 
in  using  For  this  reason  the  cardmakers, 
reject  every  kind  of  paper  which  is  soft, 
rod  without  strength.  This  paper  re- 
quires to  be  very  much  sized,  since  the 
sizing  holds  the  place  of  varnish,  to  which 
the  smoothing,  gives  a  glazed  and  shining 
surface.  To  answer  all  these  purposes, 
the  rags  require  to  be  a  little  rotted,  and 
the  mallets  strongly  armed  with  iron 
studs.  At  present,  Angoumois  is  almost 
the  only  province  in  France,  which  sells 
card-paper  to  the  Dutch,  and  the  other 
northern  nations.  The  rags  of  Angou- 
mois, have  the  peculiar  quality  of  not  turn- 
ing too  soft,  in  the  putrefaction,  and  the 
mills  of  that  province  reduce  them  to  stuff, 
though  they  be  not  much  putrefied.  The 
French,  we  believe,  excel  every  other  na- 
tion, in  this  branch  of  the  manufacture  of 
paper. 


Painters  prepare  their  paper  for  draw- 
ing, and  give  it  a  dark  ground,  which 
spares  them  much  labour  of  the  pencil 
afterwards  in  those  places  where  shade  is 
necessary.  For  this  purpose,  they  take 
white  paper  and  pass  a  sponge  over  it, 
which  has  imbibed  water  impregnated 
with  soot,  leaving  the  light  places  to  be 
formed  afterwards.  They  use  also  a  kind 
of  paper  for  drawing,  which  is  called  taint- 
ed paper.  A  light  colour  is  passed  over 
the  whole  ground,  which  deprives  the 
paper  of  its  original  brightness,  and  makes 
the  light  places  of  the  print  appear  more 
in  relievo,  and  more  luminous. 

The  method  most  common  and  most 
convenient  for  copying  a  print,  is  to  use 
oiled  paper.  The  manner  of  preparing 
this  paper  is  to  take  that  which  is  thin 
and  smooth,  known  commonly  by  the 
name  of  serpent  paper,  and  moisten  it  with 
a  composition,  of  two  parts  of  the  oil  of 
walnuts,  and  one  part  of  the  oil  of  turpen- 
tine, mixed  well  together.  A  sheet  of 
pasteboard  and  a  sheet  of  paper  are  laid 
on  a  smooth  table ;  above  them  are  placed 


PAP 

two  sheets  of  paper  to  be  prepared;  and 
a  layer  of  the  oil  applied  to  the  upper- 
most is  sufficient  to  penetrate  both.  This 
may  be  done  to  any  number  of  sheets,  and 
a  strong  sheet  of  prsteboard  is  placed 
over  the  whole.  The  heap  is  afterwards 
submitted  to  the  press,  under  which  it  re- 
mains for  two  or  three  days,  till  the  oil  be 
completely  dry.  Paper  prepared  in  this 
manner  serves  to  copy  very  readily  and 
exactly  all  kinds  of  figures  and  plans;  be- 
cause, being  altogether  transparent,  all 
the  parts  of  the  drawing,  whether  of  light 
or  shade,  are  easily  distinguished. 

Besides  the  paper  made  from  the  asbes- 
tos, it  is  necessary  for  wrapping  up  gun- 
powder and  valuable  writings,  to  have  a 
paper  that  will  not  easily  take  fire.  The 
manner  in  which  this  is  prepared  is  ex- 
tremely simple  Ordinary  paper  is  dipped 
into  boiling  liquid,  consisting  of  three- 
fourths  of  water,  and  one-fourth  of  dis- 
solved alum.  This  salt,  which  is  not  in- 
flammable, covers  the  surface  of  the  pa- 
per, and  renders  it  in  some  measure  in- 
combustible. 

In  the  season  of  verjuice,  a  little  of  it 
diluted  with  water  is  sufficient  for  oblite- 
rating any  fresh  spot  of  ink.  The  salt  of 
the  verjuice,  dissolved  in  water,  answers 
the  purpose  equally  well ;  and  the  salt  of 
the  sorrel  is  also  employed,  thongh  with 
less  effect.  If  the  spots  be  dry,  and  the 
above  acids  are  insufficient  to  eradicate 
them,  a  little  aquafortis  diluted  in  water, 
and  applied  with  the  feather  of  a  quill  or 
a  fine  hair-pencil,  will  make  them  entire- 
ly disappear. 

Books  and  manuscripts  are  sometimes 
defaced  by  accidental  stains  with  oil.  To 
remove  such  blemishes,  burn  sheeps' 
bones,  and  reduce  them  to  a  fine  powder; 
lay  a  quantity  of  this  powder  on  each  side 
of  the  stain  ;  place  it  between  two  sheets 
of  white  paper,  and  submit  it  for  twelve 
hours  to  the  press.  If  the  stains  have  not 
disappeared,  it  will  be  necessary  to  reite- 
rate the  process. 

To  make  oiled  papers  take  colours ; 
mix  with  the  colours  a  very  small  quan- 
tity either  of  the  gall  of  the  pike  or  carp ; 
and  as  these  substances  are  of  the  nature 
of  soap,  they  dissolve  the  grease  that  is  in 
the  paper,  and  permit  the  colours  to  be 
spread  over  the  surface. 

Emery  paper,  which  is  employed  for 
taking  the  rust  from  iron  without  wasting 
it,  is  made  by  impregnating  coarse  pape«* 
with  gummed  water  or  any  other  tena- 
cious substance,  and  then  covering  it  over 
with  the  finest  emery. 

The  colours  proper  for  paper  are  not 
different  from  those  used  for  other  sub- 
VOL.  TT. 


PAP 

stances,  and  are  enumerated  under  the 

article  Colour-making  They  are  applied 
with  soft  brushes,  after  being  tempered  to 
a  due  degree  with  size,  or  gum  water.  If 
the  paper  on  which  they  are  to  be  laid  is 
soft,  so  that  the  colours  are  apt  to  go 
through,  it  must  also  be  sized  before  they 
are  laid  on,  or  a  proportionably  larger 
quantity  must  be  used  along  with  the  co- 
lours themselves.  If  a  considerable  ex- 
tent of  paper  is  to  be  done  over  with  one 
colour,  it  must  receive  several  coatings, 
as  thin  as  possible,  letting  each  coat  dry 
before  another  is  put  on,  otherwise  the 
colour  will  be  unequal. 

To  gild  paper. 

Take  yellow  ochre,  grind  it  with  rain- 
water, and  lay  a  ground  with  it  upon  the 
paper  all  over;  when  dry,  take  the  white 
of  eggs,  beat  it  clear  with  white  sugar 
candy,  and  strike  it  all  over :  then  lay  on 
the  leaf  gold,  and,  when  dry,  polish  it  with 
a  tooth.  Some  take  saffron,  boil  it  in  wa- 
ter, and  dissolve  a  little  gum  with  it;  this 
they  strike  over  the  paper,  lay  on  the  gold, 
and,  when  dry,  they  polish  it. 

To  silver  paper  after  the  Chi?icse  method, 
vsithout  silver. 

Take  two  scruples  of  clear  glue  made 
of  neats'  leather,  one  scruple  of  white 
alum,  and  half  a  pint  of  clear  water ;  sim- 
mer the  whole  over  a  slow  fire  till  the  wa- 
ter is  consumed,  or  the  steam  ceases ; 
then,  your  sheets  of  paper  being  laid  on  a 
smooth  table,  you  dip  a  pretty  large  pen- 
cil into  the  glue,  and  daub  it  over  ac  even 
as  you  can,  repeating  this  two  or  three 
times :  then  sift  the  powder  oitalc  through 
a  fine  sieve,  made  of  horse-hair  or  gauze, 
over  it ;  and  then  hang  it  up  to  dry :  when 
dry,  rub  off'  the  superfluous  talcy  which 
serves  again  for  the  same  purpose.  The 
talc  you  prepare  in  the  following  manner : 
Take  fine  white  transparent  Muscovy  talc; 
boil  it  in  clear  water  for  four  hours ;  then 
take  it  off  the  fire,  and  let  it  stand  so  for 
two  days  :  then  take  it  out,  wash  it  well, 
and  put  it  into  a  linen  rag,  and  beat  it  to 
pieces  with  a  mallet :  To  10  lbs.  of  talc 
add  3  lbs.  of  white  alum,  and  grind  them 
together  in  a  little  hand  mill ;  sift  it 
through  a  gauze  sieve;  and  being  thus 
reduced  to  a  powder,  put  it  into  water, 
and  just  boil  it  up  :  then  let  it  sink  to  the 
bottom,  pour  off  the  water,  place  the  pow- 
der in  the  sun  to  dry,  and  it  will  become 
of  a  hard  consistence.  This  beat  in  a  mor- 
tar to  an  impalpable  powder,  and  keep  it 
for  the  use  above  mentioned,  free  from 
dust. 

Hh 


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iPhite  and  coloured  grounds  for  Paper- 
hangings. 

The  common  grounds  laid  in  water  are 
made  by  mixing  whiteing  with  the  com- 
mon glovers'  size,  and  laying  it  on  the 
paper  with  a  proper  brush,  in  the  most 
even  manner.  This  is  all  that  is  required 
where  the  ground  is  to  be  left  white  ;  and 
the  paper  being  then  hung  on  a  proper 
frame  till  it  be  dry,  is  fit  to  be  printed. 
When  coloured  grounds  are  required,  the 
same  method  must  be  pursued,  and  the 
ground  of  whiting  first  laid  on  ;  except  in 
pale  colours,  such  as  straw  colours,  or 
pirk,  where  a  second  coating  may  some- 
times be  spared,  by  mixing  some  strong 
colour  with  the  whiting. 

Method  of  painting  Paper-hangings. 

There  are  three  methods  by  which 
paper-hangings  are  painted.  First,  by 
printing  on  the  colours  ;  the  second,  by 
using  the  stencil;  and  the  third,  by  laying 
them  on  with  a  pencil,  as  in  other  kinds 
of  painting. 

When  the  colours  are  laid  on  by  print- 
ing, the  impression  is  made  by  wooden 
prints,  which  are  cut  in  such  manner  that 
the  figure  to  be  expressed  is  made  to  pro- 
ject on  the  surface,  by  cutting  away  all 
the  other  part;  and  this  being  charged 
with  the  proper  colours,  tempered  with 
their  proper  vehicle,  by  letting  it  gently 
down  on  a  block,  on  which  the  colour  is 
previously  spread,  conveys  it  from  thence 
to  the  ground  of  the  paper,  on  which  it  is 
made  to  fall  more  forcibly  by  means  of 
its  weight,  and  the  effort  of  the  arm  of 
the  person  who  uses  the  print.  It  is  easy, 
he  concludes,  that  there  must  be  as  many 
separate  prints  as  there  are  colours  to  be 
printed.  But  where  there  are  more  than 
one,  great  care  must  be  taken,  after  the 
first,  to  let  the  print  fall  exactly  on  the 
same  part  of  the  paper  as  that  which  went 
before;  otherwise  the  figure  of  the  design 
would  be  brought  into  irregularity  and 
confusion.  In  common  paper  of  low  price, 
it  is  usual,  therefore,  to  print  only  the  out- 
lines, and  lay  on  the  rest  of  the  colours 
by  stencilling;  which  both  saves  the  ex- 
pense of  cutting  more  prints,  and  can  be 
practised  by  common  workmen,  not  re- 
quiring the  great  care  and  dexterity  ne- 
cessary to  the  using  several  prints. 

The  manner  of  stencilling  the  colours  is 
this.  The  figure,  which  all  the  parts  of 
any  particular  colour  make  in  the  design 
to  be  painted,  is  to  be  cut  out,  in  a  piece 
of  thin  leather,  or  oil-cloth,  which  pieces 
of  leather  or  oil-cloth  are  called  stencils  ; 
and  being  laid  flat  on  the  sheets  of  paper 
to  be  printed,  spread  on  a  table  or  floor,  • 
are  to  be  rubbed  over  with  the  colour,  j 


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properly  tempered,  by  means  of  a  larga 
brush.  The  colour  passing  over  the  whole 
is  consequently  spread  on  those  parts  of 
the  paper  where  the  cloth  or  leather  is 
cut  away,  and  gives  the  same  effect  as  if 
laid  on  by  a  print.  This  is,  nevertheless,, 
only  practicable  in  parts  where  there  are 
only  detached  musses  or  spois  of  colours ; 
for  where  there  are  small  continued  lines, 
or  parts  that  run  one  into  another,  it  is 
difficult  to  preserve  the  connection  or 
continuity  of  the  parts  of  the  cloth,  or  to 
keep  the  smaller  corners  close  down  to 
the  paper ;  and  therefore,  in  such  cases, 
prints  are  preferable.  Stencilling  is  in- 
deed a  cheaper  method  of  ridding  coarse 
work  than  printing  j  but  without  such  ex- 
traordinary attention  and  trouble  as  ren- 
der it  equally  difficult  with  printing,  it  is 
far  less  beautiful  and  exact  in  the  effect. 
For  the  outline  of  the  spots  of  colour 
want  that  sharpness  and  regularity  that 
are  given  by  prints,  beside  the  frequent 
extra-lineations,  or  deviations  from  the 
just  figure,  which  happens  by  the  origi- 
nal misplacing  of  the  stencils,  or  the  shift- 
ing of  the  place  of  them  during  the  ope- 
ration. 

Pencilling  is  only  used  in  the  case  of 
nicer  work,  such  as  the  better  imitations 
of  the  India  paper.  Il  is  performed  in  the 
same  manner  as  other  painting-s  in  water 
or  varnish.  It  is  sometimes  used  only  to 
fill  outlines  already  formed  by  printing, 
where  the  piece  of  the  colour,  or  the  ex- 
actness of  the  manner  in  which  it  is  re- 
quired, to  be  laid  on,  render  the  stencill- 
ing it  or  printing  it  less  proper ;  at  other 
times,  it  is  used  lor  performing  or  deli- 
neating some  parts  of  the  desig-n,  where 
a  spirit  of  freedom  and  variety,  not  to  be 
had  in  printed  outlines,  are  desired  to  be 
had  in  the  work. 

Management  of  the  Flock  paper. 

The  paper  designed  for  receiving  the 
flock  is  first  prepared  with  a  varnish- 
ground  with  some  proper  colour,  or  by 
that  of  the  paper  itself.  It  is  frequently 
practised  to  print  some  Mosaic,  or  other 
small  running  figure  in  colours,  on  the 
ground,  before  the  flock  be  laid  on  ;  and 
it  may  be  done  with  any  pigment  of  the 
colour  desired,  tempered  with  varnish, 
and  laid  on  by  a  print  cut  corresponding 
to  that  end. 

The  method  of  laying  on  the  flock  is 
this  :  A  wooden  print  being  cut  as  is  above 
described,  for  laying  on  the  colour  in  such 
manner  that  the  part  of  the  design  which 
is  intended  for  the  flock  may  project  be- 
yond the  rest  of  the  surface,  the  varnish 
is  put  on  a  block  covered  with  leather  or 
oil-cloth,  and  the  print  is  to  be  used  also 


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>ni  the  same  manner  to  lay  the  varnish 
on  all  the  parts  where  the  flock  is  to  be 
fixed.  The  sheet,  thus  prepared  by  the 
varnished  impression,  is  then  to  be  re- 
moved to  another  block  or  table,  and  to 
be  strewed  over  with  flock,  which  is  af- 
terwards to  be  gently  compressed  by  a 
board,  or  some  other  flat  body,  to  make 
the  varnish  take  the  better  hold  of  it,  and 
then  the  sheet  is  to  be  hung  on  a  frame 
till  the  varnish  be  perfectly  dry;  at  which 
time  the  superfluous  part  of  the  flock  is 
to  be  brushed  off  by  a  soft  camel's-hair 
brush,  and  the  proper  flock  will  be  found 
to  adhere  in  a  very  strong  manner. 

The  method  of  preparing  the  flock  is, 
by  cutting  woollen  rags  or  pieces  of  cloth 
with  the  hand,  by  means  of  a  large  bill 
or  chopping-knife,  or  by  means  of  a  ma- 
chine worked  by  a  horse-mill. 

There  is  a  kind  of  counterfeit  flock- 
paper,  which,  when  well  managed,  has 
very  much  the  same  effect  to  the  eye  as 
the  real,  though  done  with  less  expense. 
The  manner  of  making  this  sort  is,  by 
laying  a  ground  of  varnish  on  the  paper ; 
and  having  afterwards  printed  the  design 
of  the  flock  in  varnish,  in  the  same  man- 
ner as  for  the  true,  instead  of  the  flock, 
some  pigment,  or  dry  colour,  of  the  same 
hue  with  the  flock  required  by  the  de- 
sign, but  somewhat  of  a  darker  shade, 
being  well  powdered,  is  strewed  on  the 
printed  varnish,  and  produces  nearly  the 
game  appearance. 

An  account  of'  the  mode  of  makivg  Paper, 
practised  in  the  United  St.ites. 
What  we  have  just  given  in  this  article 
has  been  extracted  from  the  several  ac- 
counts of  the  business  as  it  has  been  prac- 
tised in  Europe,  under  various  circum- 
stances, in  the  different  countries  ;  but  as 
most  of  our  arts  here,  have  the  advantage 
of  the  experience  and  emigration  of  all 
the  foreigners,  the  several  different  modes 
of  work  have  been  brought  over,  and 
the  practice  we  have  adopted  seems  to 
have  arisen  out  of  a  fair  comparison  of 
them  all.  We  are  also  authorized  to  state, 
that  from  the  advancement  of  the  art  here, 
the  machinery  and  proficiency  of  work- 
manship of  the  best  mills,  has  been  in- 
troduced very  perfectly,  though  not  to 
so  great  an  extent  as  it  exists  in  several 
manufactories  in  England.  We  shall, 
therefore,  now  add  a  brief  description  of 
the  business  in  all  its  several  stages,  and 
connect  with  it  some  remarks  on  the 
most  obvious  advantages  for  its  improve- 
ment. 

On  Paper-mills  and  Macliinery. 
In  the  erection  of  paper  m$s,  it  is  of  the 


greatest  advantage  to  obtain  a  large  level 

ground  near  the  moving  water-power,  and 
to  make  use  of  it  to  dispose  ot  the  various 
branches  of  the  business  as  separate  as 
possible.  The  mill,  consisting  properly 
only  of  that  part  connected  with  the  grind- 
ing of  the  rags,  and  the  machinery  at 
tached  thereto,  till  it  is  pressed  out  into 
wet  sheets  of  paper;  thus,  therefore,  a 
building  for  this  purpose,  in  a  good  mill, 
ought  to  be  made  separate,  undetached 
from  any  other:  into  this  the  rags  are 
brought  from  the  rag-house,  hereafter  de- 
scribed, and  from  this  the  sheets  of  paper 
are  taken,  after  formation,  for  drying, 
finishing,  &c-  into  the  work-house,  and, 
for  the  subsequent  processes. 

On  one  side  of  this  middle  building, 
called  the  mill,  ought  to  be  erected  a  rag- 
house,  into  which  the  rags  are  to  be  re- 
ceived, weighed,  and  kept  in  bulk  ;  in 
part  of  this  also  they  are  to  be  assorted, 
and  afterwards  dressed  on  the  screens. 
No  communication  ought  to  be  had  from 
this  building  to  the  mill,  except  by  the 
foreman  of  the  rag-house,  or  engineer, 
when  the  regular  day's  work  of  rags  are 
taken  into  the  mill  for  the  purposes  of 
being  made  into  paper 

On  the  other  side  should  be  the  general 
work-house  of  the  mill,  consisting  below 
of  a  room  to  receive  the  paper  wet  from 
the  vats,  each  morning,  after  pressing  du- 
ring the  preceding  night ;  which  room 
is  to  be  furnished  with  presses  for  press- 
ing in  the  more  advanced  state  of  the 
process,  and  with  benches  to  assort  and 
part  the  packs  on,  and  here  it  receives 
the  complete  process  of  parting  and  press- 
ing until  it  is  taken  up  in  the  loft  to  dry, 
Near  or  adjoining  this  room,  should  be 
the  sizing-house,  and  by  this  convenience 
being  at  hand,  the  sized  paper  can  be 
brought  to  be  parted  after  it  is  sized,  as 
it  is  so  done,  in  the  same  manner  as  the 
wet  paper,  after  which  it  also  is  taken  into 
the  loft  to  dry. 

Connected  with  the  sizing  room  ought 
always  to  be  built  the  kettles,  hung  in 
an  elevated  situation  for  boiling  the  size, 
and  also  for  hot  water,  so  that  the  size 
can  at  all  times  be  run  oft"  into  the  sizing 
room,  and  without  the  dirt  or  incum- 
brance of  the  fire,  or  even  the  free  pas- 
sage of  air,  which  ought  to  be  excluded. 

On  the  ground  near  this  end  or  side  of 
the  groupe  of  buildings,  ought  also  to  be 
the  hardening  room,  used  for  hardening 
the  sized  paper  in  damp  seasons,  and  for 
keeping  paper  generally  when  ready  to 
leave  the  mill. 

Above  the  work-house,  if  not  conve- 
nient on  the  same  floor,  is  the  great  finish- 


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ing  room,  called  the  salle,  with  benches 
for  picking,  sorting  and  finishing  the  pa- 
per, and  arranged  round  it,  are  the  presses 
for  pressing  the  paper  when  dry,  after 
being  sized,  or  for  finishing  those  papers 
when  dry,  which  do  not  require  sizing. 

Above  this  building  or  the  before  men- 
tioned rooms,  is  the  drying  loft,  into 
which  the  paper  is  received  after  being 
pressed  and  parted  w  hen  from  the  vats, 
or  after  being  separated  from  the  size; 
and  in  general  also  to  hang  and  dry  the 
paper  under  any  circumstances.  This 
room  ought  to  be  opened  to  the  roof  of 
the  house,  in  order  to  afford  as  much  air- 
ing as  possible. 

The  advantages  of  this  arrangement 
are  very  great,  as  it  preserves  the  stock 
of  rags,  in  which  there  is  always  much 
dust,  from  the  paper,  pulp,  &c.  which  it 
is  indispensible  to  preserve  in  the  utmost 
degree  of  cleanness.  It  separates  also 
that  part  of  the  business  where,  if  there 
is  any  risque  of  fire  owing  to  the  dryness 
of  the  paper,  and  from  the  mill,  machinery, 
and  rags ;  and  also,  as  in  this  business 
there  is  a  greater  difference  in  the  various 
stages  of  manufacture  than  in  any  other, 
from  taking  a  foul  material  and  producing 
a  most  beautiful  article  of  distinguished 
cleannesSjSO  there  is  an  especial  difference 
in  the  hands  to  be  employed,  and  conse- 
quently in  their  government.  So  much 
for  general  outline,  we  shall  now  briefly 
go  through  the  description  of  the  interior, 
and  at  the  same  time,  the  process  of  the 
business. 

The  Rag-house. 
Into  this  building  the  rugs  are  first 
brought,  and  it  is  better  to  put  them  into 
the  upper  story,  to  which  they  may  he 
hoisted  ;  in  this  have  binns  to  hold  quan- 
tities in  bulk  as  received,  and  also  binns  to 
hold  the  separate  kinds  as  they  are  sort- 
ed. 

At  one  end  of  this  story,  should  be  a 
closed  room  for  sorting  the  rags  in  win- 
ter, and  which  must  be  warmed  for  the 
people  :  in  this  room,  must  be  placed  se- 
veral long  rag  screens  or  frames  of  wood, 
with  the  open  part  covered  with  wire,  and 
having  in  the  middle,  a  rag  knife  fixed 
upright ;  the  rags  are  brought  from  the 
heap  as  received,  and  thrown  over  them, 
and  here  they  are  assorted,  into  the  dif- 
ferent qualities, ready  to  go  into  the  binns; 
when  rags  come,  as  they  often  do,  two 
kinds  sowed  together,  they  are  separated 
by  drawing  across  the  knife,  and  each  qua- 
lity, is  thrown  into  a  separate  heap  The 
first  are  fine  white  rags,  linen,  or  cotton  ; 
the  second,  coarser  in  texture,  and  the 
third,  hard  rags,  generally  linen,  or  low, 


cotton ;  fourth,  inferior,  of  the*  same  de 
scription  ;  then  comes  the  colours,  cordu  - 
roys and  other  sorts,  generally,  as  the  mill 
is  to  be  employed  the  kinds  are  adapted 
thereto. 

It  often  happens,  that  when  a  particular 
branch  of  work  is  chosen  for  a  mill,  the 
rags  suitable  for  it  are  sorted  out,  and  the 
inferior  ones,  sold  to  much  greater  advan- 
tage- than  manufacturing  them,  and  the 
mill  at  the  same  time  is  working,  at  its 
particular  line,  at  a  saving  of  implements, 
which  cannot  readily  be  used,  in  both  the 
fine  and  coarse  branches. 

When  the  rags  are  sorted  in  this  man- 
ner, they  are  ready  for  use,  and  when  fine, 
seconds,  or  other  qualities  are  to  be  used, 
a  quantity  of  them  are  taken  into  the 
lower  room,  which  is  called  the  rag  dress- 
ing room,  this  room  is  furnished  with  a 
rag  screen,with  a  knife  fixed  in  it,  for  each 
person  and  it  ought  to  be  placed  with 
the  left  hand  against  a  window,  and  a 
lage  box  at  the  right  hand,  divided  into 
three  parts.  The  screens  are  placed  on 
one  side  <>f  the  room,  along  the  row  of 
windows,  with  a  passage  for  ihe  rag  dress- 
er between  each:  here  the  rags  are  brought 
down,  and  cut  ready  for  the  engineer,  into 
small  pieces,  and  all  the  seams  opened, 
all  dust  and  dirt  carefully  taken  out,  and 
they  are  occasionally  rubbed  hard  over  the 
wire,  so  as  to  shake  ofTVil  the  lint.  Now 
as  the  sorting  of  the  rags,  in  the  upper 
room  is  never  very  perfect,  here  this  is 
corrected,  and  the  rags  are  ready  for 
use. 

The  engineer  then  takes  them  from  the 
sorter,  and  looks  them  over,  on  a  larger 
screen,  and  after  finding  them  well  done, 
puts  them  into  the  duster,  which  is  a  roll- 
ing screen,  moved  by  the  machinery  of 
the  mill ;  and  situate  either  in  the  mill  or 
in  the  rag-house,  as  before  mentioned  ;  in 
this  they  are  revolved  about  half  an  hour, 
and  the  dust  and  lint  much  shaken  out  -, 
after  this  the  engineer  looks  them  over 
again,  and  prepares  them  for  the  engine; 
they  are  then  taken  into  the  mill. 

The  Mill. 

A  good  mill  for  fine  work,  ought  to 
have  two  sorts  of  engines;  the  one  for 
•washing,  the  other  for  beating. 

A  washing  engine  as  now  used,  is  form- 
ed of  a  chest  about  9  feet  long,  by  4  feet 
wide,  and  one  foot  ten  inches  deep  ;  the 
beating  engine  is  rather  shallower,  and 
about  11^  feet  long;  in  each  of  them  is 
fixed  a  cylinder,  on  one  side  extending 
half  the  breadth  of  the  engine,  and  which 
cylinder  called  the  role,  contains,  for  the 
washing  engine,  36  thick  bars,  set  at 
equal  distances  round  it,  and  extending 


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out  about  two  inches,  works  over  a  plate 
containing  about  eight  burs,  screwed  tight 
together,  and  fixed  firmly  into  the  bed  of 
the  engine,  at  the  bottom,  but  in  which 
the  circle  of  the  role  runs  The  role  of 
the  beater  is  much  the  same,  but  contains 
48  thinner  bars ;  moving  over  a  plate, 
which  has  from  8  to  15  bars,  the  latter  in 
fine  mills,  are  formed  of  steel  saw  blades, 
separated  by  thicker  bars  of  copper,  and 
laid  at  a  small  angle  witli  the  bars  of 
the  role;  the  stuff  obtains  a  circular 
revolution  round  the  engine,  from  the 
motion  of  the  role,  and  becomes  ground 
or  beaten,  as  it  is  termed,  by  successively 
passing,  between  the  revolving  role  and 
the  plate  ;  the  role  being  covered  with  a 
box,  called  the  cub,  in  which  there  are 
two  strainers  of  wire,  and  the  water  is  dis- 
charged by  pipes  behind  them,  as  the  mass 
of  water  and  rags  is  thrown  against  them, 
by  the  role,  when  revolving  in  its  process 
of  grinding. 

As  soon  as  the  engine  is  to  be  used, 
it  is  filled  with  water  to  near  the  top,  and 
the  charge  of  rags,  which  is  100  pounds, 
prepared  and  brought  into  the  mill,  is  put 
in  by  handfuis  into  the  washing  engine,  in 
which  the  role  is  kept  revolving,  drawing 
them  under  it.  After  the  rags  are  put 
in,  and  become  well  wet,  the  washing 
roie  is  lowered  upon  the  plate  for  some- 
time, in  order  to  break  them  open,  and  it 
is  then  kept  running  upon  them,  more 
like  bruising  them  than  grinding,  for  five 
or  six  hours ;  if  coarse  rags,  longer,  or 
fine  tender  rags  a  shorter  time ;  in  this 
process,  a  large  quantity  of  water  is  kept 
passing,  both  in  and  out  of  the  engine,  as 
it  is  the  chief  object  of  the  engineer,  to 
admit  a  very  large  quantity  of  water,  to  go 
through  the  rags,  and  in  order  to  do  this, 
the  bars  of  the  role  are  always  blunter, 
than  is  necessary  for  beating.  Herein  is 
the  advantage  of  a  washing  engine,  the 
revolution  is  also  made  much  slower, 
by  having  a  larger  trundle  head,  if 
on  the  same  wheel  with  the  beating  en- 
gine, and  it  never  exceeds  120  turns  per 
minute.  When  the  rags  are  washed,  thev 
are  let  through  a  valve,  which  is  opened 
in  the  bottom  of  the  washing  engine,  into 
the  beating  engine,  where  they  are  wash- 
ed for  a  short  time,  to  remove  any  dirt 
which  may  have  collected  in  the  pipes, 
and  after  this  they  are  regularly  beaten 
for  the  pulp,  which  takes  a  process  of 
about  six  hours  longer,  or  shorter,  accord- 
ing to  the  hardness  or  tenderness  of  the 
rags;  the  revolutions  of  this  role,  are  from 
120  to  160  times  in  a  minute,  these  being 
the  slowest  and  greatest  speed. 

The  management  of  the  beating  engine, 
is  of  the  highest  importance  to  the  fabric 


of  the  paper,  and  must  always  be  carefully 
attended  to  ;  the  different  effects  are  pro- 
duced by  two  methods,  diminishing  the 
speed  of  the  role,  and  by  lowering,  or 
raising  it  from  the  plate.  The  best*  stuff 
is  made,  when  the  rags  are  hard  and  firm, 
and  when  the  motion  of  the  role  is  kept 
pretty  swift,  gradually  lowered  on  the 
plate. 

If  any  colouring  of  blue  or  other  matter, 
is  to  be  introduced  into  the  paper,  it  is 
done  when  first  put  into  the  beater :  this 
is  generally  done  in  fine  papers ;  blue 
either  of  indigo,as  used  in  blueing  clothes, 
or  a  solution  of  that  article,  in  sulphuric 
acid,  strewed  in  small  quantities,  called  by 
druggists,  Saxon  blue  ;  or  the  fine  cobalt 
blue,  called  smaltz,  are  used ;  the  two  for- 
mer being  soluble  in  water,  dye  the  paper, 
the  latter  being  insoluble,  is  intimately 
mixed  through  it,  and  colours  it  in  mass  ; 
the  proportions  of  each  of  these,  is  accord- 
ing to  the  colour  required,  and  in  this  the 
artist  must  be  governed  by  experience,  as 
it  differs  in  thick  and  thin,  and  in  fact  in 
all  kinds  of  paper. 

Paper  is  often  (of  the  lower  qualities,) 
sized  in  the  engine,  principally  printing 
paper,  which  saves  much  expense,  and 
the  trouble  of  the  future  process,  of  sizing 
it  with  glue  ;  it  is  done  by  strewing  into 
the  engine  while  beating,  and  immediate- 
ly after  the  washing  is  completed,  about 
one  pound  of  fine  powdered  alum,  and  a 
gill  of  cold  drawn  linseed  oil. 

The  greatest  care  ought  to  be  taken, 
not  to  suffer  any  specks,dirt  or  iron  mould, 
to  get  into  the  paper,  for  this  purpose  all 
the  implements  of  bowls  8cc.  used,  ought 
to  be  of  copper,  and  ail  the  conveying 
pipes  lead;  at  each  engine  there  is  also 
a  water  box  for  rincing  it,  and  no  stuff 
ought  to  be  permitted  to  remain,  attach- 
ed to  any  part,  as  in  a  single  instance,  it 
ruins  a  whole  engine  of  rags,  by  coming 
off  unbeaten,  and  mixing  in  this  state  with 
the  mass,  forms  afterwards  knots  and 
lumps,  which  areruinous  to  the  workman- 
ship of  the  paper,  causing  holes  and  other 
evils,  in  the  after  operation. 

When  the  stuff  becomes  beaten,  it  is 
discovered  by  repeated  trials,  in  a  bowl 
of  water,  and  by  experience  ;  it  is  however 
observable,  that  the  best  paper  is  made, 
when  the  stuff  is  polished,  by  long  beating 
in  the  engine,  with  a  plate  moderately 
dull,  as  the  principal  is  not  to  grind  or 
mince  the  stuff  finer  in  proportion,  than 
it  oug-ht  to  be,  for  the  fineness  of  the  pa- 
per ;  if  it  is,  the  paper  is  always  tender 
in  its  manufacture  ;  a  loss  arises  in  quality 
from  being  broken  in  its  subsequent 
stages,  and  also  in  its  use. 

After  the  stuff  is  sufficiently  beaten,  it 


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is  let  down  by  a  valve,  through  a  pipe 
into  a  stuff  chest,  or  reservoir,  which 
ought  to  be  a  long-  deep  square  box  capa- 
ble of  containing-  about  four  engines,  and 
to  have  a  small  box  of  clear  water  to  wash 
any  stuff  which  may  adhere  to  its  sides ; 
in  this  the  stuff  collects,  and  is  drawn  off 
for  use  by  another  valve,  whence  it  de- 
scends through  a  pipe  to  a  serving  chest 
at  the  vat.  If  the  stuff  chest  contains 
V  four  engines,  it  is  about  right,  as  it  will 
keep  a  supply,  in  case  of  any  accident 
to  the  machinery,  and  by  these  means 
stuff  may  be  got  a-head,  which  is  occa- 
sionally a  relief  to  the  engineer;  but  four 
engines  is  capacity  enough,  as  more  stuff 
sometimes  becomes  thick,  or  injures  by 
the  water  standing  too  long  in  hot  wea- 
ther. 

The  vat  is  a  square  box  of  about  six  feet 
•each  way  at  the  top,  sloping  to  about  four 
feet  at  bottom,  about  three  and  a  half  feet 
deep  ;  one  side  or  back  is  perpendicular, 
and  through  this  is  inserted  die  copper 
pot,  having  in  it  a  grate  and  a  fire  to  warm 
J  the  vat ;  and  from  the  pot  a  pipe  or  elbow 
is  taken  out  in  the  vat,  which  draws  the 
fire  through  the  pot,  and  heats  the  vat 
much  better ;  the  smoke  from  thence 
passes  into  a  chimney ;  and  the  vat 
ought  to  be  so  constructed  at  the  side  of 
the  room,  that  the  fire  place  may  always 
be  on  the  outside  of  the  house.  The 
vat  pot  must  always  be  so  set  in  the  vat, 
as  to  be  covered  with  water* 

The  vat  man,  in  commencing  work, 
fills  the  vat  with  water  from  the  spring 
pipe,  which  ought  always  to  be  at  the 
side  of  the  vat,  and  with  the  stuff  from 
the  stuff  chest  at  the  same  time,  and 
mixes  it  thick  or  thin  according  to  the 
sort  he  means  to  make  from  the  stuff; 
it  is  always  delivered  to  the  vat  at  the 
right  hand  side  of  the  workman,  and  he 
regulates  his  work  by  having  drawn  the 
stuff  into  the  small  box  or  sewer  attached 
to  the  side  of  the  vat,  and  also  at  the  end 
f  the  pipe  from  the  stuff  chest,  there 

i»g  again  a  valve  from  the  feeding  box 
r.to  the  pipe  which  leads  thence  to  the 
rat :  this  answers  as  a  guage  for  the  fu- 
ture supply  of  the  stuff 

The  vat  being  supplied,  is  kept  heat- 
ed by  the  pot  to  about  160°,  say  for  all 
tine  papers.  The  vat-man  then  com- 
mences his  work. — He  then  stands  at  the 
breast  of  the  vat,  and  dips  into  it  the 
mould.  The  mould  is  of  a  frame  of  wood 
formed  with  bars,  and  on  it  is  placed 
wires,  either  fastened  in  bars,  or  wove 
finer  or  coarser  according  to  the  work. 
When  the  mould  is  of  bar  wire,  the 
coarsest  has  about  twenty  wires,  with  a 
5p_ace  about  equal  to  their  thickness  in 


an  inch.  When  wove,  the  wires  are  of 
meshes  from  25  to  60  to  an  inch.  The 
mould  is  surrounded  by  a  moveable 
frame  called  a  dickle,  which  is  put  on 
when  the  mould  is  dipped  in,  and  se- 
cures the  stuff  on  the  mould,  then  it  is 
taken  off,  and  in  turn  put  on  the  other 
mould.  The  workman  dips  the  mould 
into  the  vat,  after  taking  it  in  his  two 
hands  each  about  the  middle  of  the  two 
ends,  and  pressing  down  the  deckle  with 
his  two  thumbs;  by  sinking  down  the  side 
of  the  mould  which  is  next  him  nearly  per- 
pendicular into  the  stuff  about  half  way 
of  the  mould,  and  then  gently  bringing  it 
up  level  with  the  stuff  on  its  surface.  As 
soon  as  it  is  out  of  the  water  the  stuff  be- 
gins to  sink  by  the  water  passing  through 
the  wires ;  but  he  takes  this  instant,  in 
which  it  poises,  to  gently  throw  off  some 
of  the  water  over  the  opposite  side  of 
the  mould,  as  it  will  run  that  way  after 
his  bringing  it  up  from  the  vat;  and  in  the 
process  of  forming-  the  sheet,  he  shakes  it 
in  a  similar  manner  to  a  person  sifting 
cinders. 

The  sheet,  if  well  formed,  will  at  once 
have  a  level  polished  surface,  free  from 
rash  or  frayed  stuff,  and  care  must  be  ta- 
ken not  to  let  any  drops  get  into  the  sheet 
from  the  dickle ;  the  stuff,  if  properly 
beat  in  the  engine,  will  work,  as  the  work- 
men call  it,  we*,  that  is,  stay  a  longer  time 
on  the  mould ;  but  if  ground  fine,  will 
sink  almost  at  once,  and  when  this  is  the 
case,  it  will  never  make  good  paper. 

The  stuff  in  the  vat,  particularly  if 
smaltz.  be  used,  must  be  frequently  stir- 
red, or  have  a  hog,  which  is  a  machine 
turned  by  a  stream  of  water  on  a  small 
water-wheel  outside  the  vat,  and  unites 
by  a  water-tight  brass  collar,  with  a  set 
of  flyers  inside  the  vat,  almost  like  the 
fivers  in  a  wheat  fan.  It  is  a  machine  now 
in  universal  use  in  a  fine  vat.  A  dash  like 
that  for  a  churn  is  also  occasionally  used, 
to  keep  the  stuff  evenly  suspended,  or  the 
workman  will  have  too  much  trouble  to 
form  his  sheets  as  even  as  they  ought 
to  be. 

The  vats  ought  always  to  be  situated 
in  rooms  or  offsets  of  the  mill,  and  lighted 
well,  kept  close  to  themselves  ;  sky-lights 
are  always  best. 

The  vat-man  having  formed  the  sheet 
of  paper,  passes  it  to  the  coucher  over  a 
small  vat-bridge  at  the  left  hand  corner  of 
the  vat.  and  the  coucher  receives  it  with 
his  left  hand,  and  rests  one  side  of  it  in  a 
notched  piece  of  wood  called  a  jack, 
where  it  drains ;  the  coucher  having  pre- 
viously pushed  a  mould,  from  which  he 
had  just  taken  the  newly  formed  sheet, 
along  the  middle  of  the  vat  on  the  vat- 


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Bridge,  for  the  vat-man  to  receive  for  the 
next  sheet. 

The  coucher,  having-  laid  the  felt  over 
the  sheet  of  paper  he  had  last  couched, 
takes  the  mould  from  the  jack  with  his 
left  hand,  brings  it  round  into  his  right, 
with  which  he  reverses  the  mould  by  rest- 
ing the  side  against  the  right  hand  sid\ 
of  the  post  of  felts ;  then  reverses  his 
hands  by  putting  his  left  hand  to  the  top 
or  side,  and  his  right  hand  to  the  side  of 
the  mould,  which  touches  the  felt,  and 
turns  it  over,  gently  pressing  the  t:ame  on 
the  felt ;  the  sheet  will  then  be  left  on  the 
ielt,  and,  if  well  done,  very  perfect;  but 
subject,  as  well  as  in  making,  to  various 
accidents,  which  are  named  and  well 
known  by  the  technical  names  of  the 
trade,  and  which  the  workman  only  can 
correct. 

The  coucher  lays  alternately  a  sheet  of 
paper  and  a  felt ;  but  the  nap  sides  of  the 
felts  must  always  be  uppermost,  as  the 
paper  sticks  to  it.  When  125  sheets,  or 
5  quires,  are  made,  the  felts  are  all  used, 
and  the  pack  or  post  put  under  the  press, 
which  is  filled  up  to  the  screw,  with  the 
head  blocks,  and  the  engineer,  loft's-man, 
vat-man,  and  others,  press  it  with  a 
lever  of  about  17  feet  long,  to  squeeze 
it  as  dry  as  possible,  the  paper  thence 
obtains  its  consistency  and  firmness  The 
press  is  then  stricken  off,  and  the  pack  is 
drawn  through  to  the  opposite  side  of  the 
press,  where"  the  lay  boy  takes  the  paper 
off  from  between  the  felts,  throwing  each 
felt  on  a  board  or  bench,  which  is  fixed  in 
the  press  for  the  purpose,  and  from  which 
the  felts  are  taken  again,  and  used  by  the 
coucher  in  his  subsequent  post. 

The  packs  collected  during  the  day  are 
usually  pressed  in  the  vat  press  after  the 
work  is  done,  and  left  to  stand  till  next 
morning,  to  acquire  a  grain,  previous  to 
being  taken  (he  next  day  into  the  work- 
house. 


The  felts  for  couching  are  made  of 
thick,  open  wove,  woollen  cloth,  general- 
ly twilled,  and  are  desirable  to  be  very 
spongy,  and  thicker  or  thinner  according 
to  the  heaviness  of  the  sheet  and  size  of 
the  paper.  Post  felting  is  necessary  to  be 
the  finest  and  thinest,  as  it  is  the  thinest 
paper  made,  and  the  large  thick  paper 
must  have  thick  felting,  in  order  to  ab- 
sorb the  water,  which  would  otherwise 
cause  the  paper  to  slip  in  the  couching, 
or  run  from  the  sheet  before  pressing, 
which  would  be  very  injurious  to  it.  A 
felting  is  therefore  made  on  purpose  for 
papers  of  each  sort,  and  not  fulled,  but 
sheared  on  one  side,  the  paper  always  ad- 
hering to  the  nap,  which  is  the  side  kept 
up,  and  on  which  the  paper  is  laid. 

As  soon  as  the  paper  is  taken  from  the 
felts  by  the  lay-boy,  some  of  the  sheets 
are  to  be  dried,  in  order  to  try  its  weight, 
which  is  very  material,  and  if  too  heavy 
or  too  light,  the  vat-man  is  instructed  to 
correct  it. 

The  number  of  posts  made  per  day  is 
regulated  by  the  day's  work  agreed  to 
be  made  for  each  sort  of  paper;  which 
varies  on  each  size,  the  smaller  size:; 
having  the  greater  quantity  for  a  day's 
work,  and  of  these  the  foolscap,  pot,  and 
in  some  instances  the  demy,  are  made 
two  sheets  on  each  mould,  the  sheets  be- 
ing divided  by  a  transverse  bar,  separate 
on  the  mould,  and  are  taken  up  from  the 
felt. 

The  accustomed  day's  work  in  Ameri- 
ca is  much  less  than  in  England  ;  they  are 
exhibited  in  the  following  table,  and,  as 
this  place  affords  us  the  best  opportunity, 
we  shall  here  give  a  complete  list  of  the 
names,  sizes,  and  weights  of  all  the  papers 
usually  made ;  observing,  however,  that 
variations  continually  take  place,  for  par- 
ticular orders,  not  in  the  usual  line  of  bu- 
siness. 


I 

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Statement  of  the  Weights^  Sizes^and  Day's  work  of  Pajier  manufactured 
in  the  United  States  and  in  England :  obtained  for  the  Paper  maker's 
Society,  and  presented  per  report  January  1812. 


Denomination. 


Atlas  double 
Atlas 

Inferior 

Small 
Columbia 
Copy  w  riling 
Crown  single  - 

Inferior 

Double  - 
Inferior 

Tissue 
Cartridge  square 
Cartridge 

Do.  Royal 
Copy  plate 
Crown  plate 
Demy  single  - 

Inferior 

Plate 

Plate 

Short 

Tissue 

"Writing 

Large  double  - 
Double 
Elephant 

Common 
Fan,  large  - 

Small 
Foolscap,  Spanish 

American 

Second 
Eagle,  American 

Grand 
Imperial,  Writing 

Plate 
Littress 

Medium,  Writing 

Printing 
Post,  Thick  large 

Thin  large  - 

Thick 

Thin 

Extra  thin  - 

Small 
Pott,  Fine 

Second 

Double  - 
Royal,  Writing 

Plate 


ENGLAND. 


55  by 
26  1-4 
26  1-4 

25 

■23  1-2 

16 

15 

15 

30 

30 

15 

241-4 
21 

19  1-4 

16 

15 

17  1-2 


15  1-2 
14 

171-2 
15  1-2 

28 
36 

23 
23 

1-2 
22  1-2 

13  1-2 

13  1-2 

263-4 
22 

22 

131-2 
17  1-2 
18 

161-2 
161-2 
15  1-4 
151-4 
151-4 
13  1-2 
121-2 
12  1-2 
17 

191-4 
19  1-4 


UNITED  STATES. 


incites. 

Weight.  j 

Day's  work 
in  reams 
per  day. 

Size  in  inches. 

Weight. 

Day's  work 
in  reams 
per  day. 

31  1-2 

236 

34 

98 

2$ 

26  by 

34 

90 

2 

34 

96 

31 

34  1-2 

100 

23  1-2 

34 1-2 

90 

1 

20  1-4 

17 

9 

20 

15 

10 

141-4 

181-4 

18 

20 

15 

10 

14  1-4 

181-4 

20 

24 

5 

20 

23 

5 

20 

5 

25 1-2 

56 

5 

26 

56 

5 

24 

50 

5 

19  14 

24 

26 

20  1-4 

25 

9 

20 

22 

10 

141-4 

181-4 

23 

Of) 

20^ 

7 

17  1-4 

211-4 

16 

6 

38 

7 

30 

6 

20 

26 

6 

201-4 

25 

9 

22 

7 

7 

20 

24 

6 

15  3-4 

20 1-4 

24 

*i 

40 

60 

3 

38  1-2 

50 

s§ 

28 

40 

4£ 

28 

38 

4ir 

201-2 

91 

131-2 

8 

16  3-4 

15 

10 

13  1-4 

10  1-2 

14 

8 

163-4 

15 

10 

13  1-4 

161-2 

12 

8 

24 

39 

110 

1 

40 

120 

30  1-4 

80 

3 

22 

301-4 

75 

2 

30  1-4 

80 

3 

22 

301-4 

17  1-2 

17 

10 

14 

16  1-2 

15 

8 

22 1-: 

34 

5h 

17  3-4 

221-2 

23 

22 

•3 

18 

23 

20 

5£ 

21 

21 

6 

16  3  4 

211-4 

21 

16 

6h 

161-2 

21 1-4 

191-S 

!  13 

6i 

191-5 

>  18 

7 

191-5 

1  8 

16  1-5 

>  10 

10 

121-2 

151-S 

10 

15  1-5 

2  10 

12 

15  1-^ 

2  9 

12 

25  1-5 

I  18 

6 

H 

24 

45 

6 

19  1-8 

24 

24 

46 

5 

Drawing 


Music 


PAP 


PAP 


Denomination. 

ENGLAND. 

UNITED  STATES. 

Size  in  inches. 

Weight. 

Day's  work 
in  reams 
per  day. 

Size  in  lQchcs. 

Weight. 

Day's  work 
in  reams 
per  day. 

itoyai,  iAnig  - 

1ft 
10 

07  1  0 

AK 

5 

191-8  24 

Printing 

1Q  1  A 

9A 
A1* 

9ft 

6 

99 

5 

Inferior  - 

1Q  1  A 

9/1 

6 

191-8  24 

90 

5 

Superroyal,  Writing 

iy  l-** 

07  1  O 

4 

191-2  27 

American,  1 

9 1  1  A     97 1  9 

newspapers,  3 

Blue  Demy 

17  1  9 

90 

1  « 
lo 

7 

Platting 

1  9 

Vm 

7 
( 

Blue  Elephant  * 

9Q 

00 
Jo 

A\ 

Crown,  Blue  &.  single 

1  % 

1  /I 
14 

10 

Blue  Royal 

19  1-2 

9/1  1  A 

6 

Blue  couples 

12 

1 0 

on 

10 

Or 

9 

7  1-2 

90 

10 

Double  2  pound 

24 

ifi 

lo 

4k 

2  pound  single 

16 

11 

Q 

y 

9" 

Lumber  hand 

23 

18 

19 

7 

Middle  hand  - 

22 

16 

16 

Purple  royal 

19  1-2 

24  1-4 

26 

6 

Royal  hand,  thick 

24 

19  1-2 

Hand 

VA 

19  1-4 

994. 

6 

Small  hand 

19  3-4 

16 

12 

10 

Double 

32 

20 

24 

5 

Sugar  blue 

21 

23 

150 

Smaller  size  - 

18  3-4 

27 

112 

Demy  size 

171.2 

22 

70 

6 

Crown  size  - 

15 

20 

50 

6 

Blue  crown,  Double 

20 

30 

24 

5 

Middle  hand  do. 

31 

21 

30 

Bag  cap 

23  1-2 

19 

50 

6 

Four  pound 

20 

16 

40 

9 

Double  four  pound 

33 

20 

80 

4* 

Pound  and  half 

12 

10 

24 

10 

Pound  couples  - 

9 

71-2 

24 

10 

T To r m  r*an 

M-XcLl  111    V/AU  - 

24 

10 

56 

6 

Imperial  cap 

29 

22 

90 

44 

Kentish  cap 

21 

18 

36 

7 

Small  cap  - 

20 

15 

16 

12 

Single  2  brown 

16 

11 

15 

10 

Before  leaving  the  stage  of  the  busi- 
ness last  described,  we  shall  mention 
some  matters  which  refer  to  the  pre\  ious 
parts  of  the  subject. 

The  description  of  the  mill  now  given 
is  not  only  the  most  approved  for  prac- 
tice, but  every  other  plan  of  mills  must 
gradually  go  out  of  use,  together  with 
machinery,  8cc.  as  the  true  interest  of  the 
business  is  attended  to  :  thus  of  the  mor- 
tars first  introduced  here,  we  believe  none 
remain ;  the  cylinders  answering  every 
purpose  of  good  manufacture,  and  vastly 
more  expeditious  and  preferable  in  every 
respect.  The  mortars,  it  is  true,  made 
very  excellent  tough  paper,  but  very 
VOL.  TI. 


slow,  and  were  used  before  the  de- 
mand was  great,  or  the  art  of  manag- 
ing cylinders  was  known.  Copperplate 
papers  were  made  very  well  with  them, 
where  the  sheet  was  not  required  to  be 
line,  clear,  and  even,  and  where  the  tex- 
ture was  desired  to  be  open,  not  close  and 
firm.  They  were  first  introduced  here 
by  the  Germans. 

The  fermentation  never  has  been  adopt- 
ed or  even  known  here  ;  it  is  certainly  in- 
jurious to  the  character  of  the  manufac- 
tory, that  the  idea  of  its  being  necessary 
should  obtain,  as  it  is  contrary  to  the 
whole  economy  of  the  art.  The  princi- 
ple of  forming  paper  stuff  is  not  to  rot  01 


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destroy  the  material,  but  carefully  to 
cleanse  it  from  all  extraneus  matters,  to 
take  the  sound  good  rags,  which  alone 
can  make  a  valuable  article,  and  by  wash- 
ing and  beating  them,  to  dissolve,  and  af- 
terwards re-arrange  them,  by  a  course  of 
workmanship,  so  that  the  fibres  of  the 
rags  are,  under  a  good  vat -man,  matted  to- 
gether by  his  work  on  the  mould,  with 
the  same  art  and  dexterity  that  the  fur  is 
formed  into  the  felt  of  hats. 

Throughout  the  process  of  forming  the 
paper  in  the  mill,  as  we  have  observed, 
the  utmost  care  must  be  paid  to  cleanli- 
ness. For  this  purpose,  the  finest  spring 
water  is  obtained,  and  a  settling  pond,  or 
where  the  situation  of  the  mill  admits  of 
it,  often  a  handsome  fountain  is  erected, 
where  it  is  collected  and  pumped  up,  for 
the  engine  vats,  &c.  and  it  undergoes  va- 
rious exposures  for  settling  and  filtration, 
before  it  is  used ;  the  water  course  of  the 
creek  being  only  used  to  turn  the  water 
power,  or  machinery  of  the  mill. 

We  have  stated  also  in  this  account  the 
various  machinery,  so  situated  as  to  run 
throughout,  from  one  engine  to  another, 
and  to  the  stuff  chest  and  vat  by  pipes 
and  valves,  which  is  by  far  the  best  me- 
thod, and  ought  always  to  be  accomplish- 
ed if  possible,  and  may  be  done  by  hav- 
ing the  gearing  elevated  by  vertical  ma- 
chinery, It  is  also  of  great  consequence 
to  have  all  the  different  receptacles  of  the 


This  room  is  furnished  with  the  pack 
presses,  generally  about  four,  with  screws 
of  a  fine  thread,  so  as  to  press  powerful- 
ly. The  pack  room  ought  to  be  tight, 
particularly  about  the  benches,  and  kept 
free  from  any  passage  for  people,  or  the 
hands  of  the  mill,  as  in  its  wet  state  the 
paper  is  liable  to  injury. 

One  parter  is  generally  enough  for  each 
vat,  and  parting  the  work  of  the  preced- 
ing day,  is  a  day's  work.  By  parting  the 
paper,  the  surfaces  of  the  sheets  are  chang- 
ed, and  become  smooth,  the  ridges  left  in 
them  by  the  wires  are  displaced,  and  much 
flattened.  The  parters  ought  always  to 
take  out  all  loose  specks,  lumps,  and 
moats,  which  may  be  on  the  paper,  and 
which,  if  they  pass  this  stage  of  the  bu- 
siness, become  dried  in.  and  cannot  be  got 
out  till  by  the  pickers,  after  it  is  sized  , 
which  is  very  wrong,  as  the  suface  of  the 
paper  is  injured  by  taking  them  out  at  that 
time.  In  addition  to  this,  if  the  paper  be- 
comes broken  at  this  time,  by  taking  out 
the  moats,  it  can  be  returned  without  loss 
to  the  engine,  but  it  cannot  after  it  is 
sized. 

In  draiwig  paper,  and  others  of  fine 
qualities,  the  packs  are  parted  a  second 
time,  after  an  intermediate  pressure.  The 
pressings  are  performed,  after  parting  by 
setting  the  press  full  of  packs,  and  press- 
ing by  the  lever,  until  the  water  conies  out 
on  the  edges  of  the  packs ;  they  must 


stuff  coated  with  lead;  engines,  stuff  j then  be  left  half  a  day,  and  pressed  again, 
chests,  vats,  &c.  and  all  the  pipes  of  lead,  ;  till  it  comes  out  again,  and  so  on  for  two 


and  the  valves  of  brass  or  copper. 


or  three  days.    The  grain  by  this  means 


Having  now  described  the  machinery  J  is  very  nicely  obtained,  and  if  not  done  at 
and  process,  so  far  as  to  produce  paper  ;  this  time,  the  paper  can  never  become 
in  water  leaf,  or  its  first  formation,  ready 


for  the  workhouse,  we  shall  proceed  to 
the  further  branch  of  the  business  in  the 
workhouse,  leaving  the  mill,  as  the  paper 
is  no  farther  connected  with  it. 

As  the  names  have  been  given  hereto- 
fore to  the  several  kinds  of  paper,  it  may 
"he  worthy  of  observation,  that  most  of 
£/jf>wj,  as  well  as  of  the  departments  of 
the  mill,  are  of  French  origin,  and  that 
they  designate  probably  the  advancement 
■of  the  business  from  that  country,  thus  : 
the  terms  salie,  vat,  couching,  retree,  de- 
mi,  columbeir,  grand  raisin,  grand  Jesus, 
are  names  in  the  trade,  and  of  the  seve- 
ral kinds  of  paper  which  have  been  given 
it  in  that  country. 

Work -house. 
The  paper  being  pressed  from  the  vat, 
^js  termed,  in  water  leaf ;  and  this  term  is 
given  it  until  it  is  sized.  It  is  in  this  state 
brought  into  the  parting  room,  where  it  is 
laid  on  the  benches,  and  the  preceding* 
clay's  work  is  parted  sheet  by  sheet,  j 


smooth. 

The  greatest  care  should  be  taken  not 
to  press  too  suddenly  ;  as  the  presses  are 
I  very  forcible,  and  the  paper  may  be  de- 
}  stroyed  by  too  hard  pressing.  The  sheets 
!  are  also  subject  to  peel  in  the  parting ;  the 
I  nicest  parting  is  therefore  requisite,  as,  if 
the  sheets  are  not  perfectly  true  over  each 
other,  the  edges  of  the  prominent  sheets 
dry  sooner  when  the  paper  is  sized,  than 
the  others  do,  and  this  is  the  cause  of  the 
rents  and  fractures,  so  frequent  in  the 
sheets,  and  of  the  loss  in  the  manufac- 
ture :  an  excellent  criterion  for  judging  of 
the  parting  being  well  done,  is  to  pass  the 
dickle  over  the  parted  pack :  if  well  done, 
and  none  of  the  pack  is  uneven,  it  will 
pass  over  the  pack  to  the  bottom.  When 
the  paper  is  duly  parted,  and  sufficiently 
pressed,  it  ought  to  be  removed  into  the 
loft,  to  be  hung,  but  in  this  respect  at- 
tention must  be  paid  to  the  weather. 

If  warm  weather,  of  summer,  and  to 
lerably  fair,  the  sooner  the  paper  is  hung 
the  better,  as  it  is  subject  to.  mildew, *n<«! 


PAP 


PAP 


it  over  the  rope,  which  takes  the  place  Oi 
the  cross  as  lie  draws  it  away. 

The  treble  ropes  ought  to  be  made  of 
coarse  hair  from  the  long  hair  of  cows  or 
oxen,  as  it  is  soft,  and  does  not  injure  the 
texture  or  surface  of  the  paper ;  and  these 
ropes  being  a  larger  diameter  than  those 
of  hemp,  as  well  as  from  the  openness  of 
the  surface,  permit  the  paper  to  hang  free, 
and  the  air  to  pass  under ;  they  also  last 
much  longer  than  the  hemp. 

The  ropes  of  the  lower  treble,  being 
filled  with  paper  from  one  side  to  the  other, 
it  is  pushed  up  the  uprights  to  the  top, 
unci  another  spread  in  the  same  manner ; 
and  when  filied  is  pushed  up  to  it,  so  as 
to  leave  a  space  between,  for  air  ;  and  al- 
ternately the  room  is  filled,  down  to  about 
four  or  five  feet  of  the  floor,  with  more  or 
less  trebles,  which  are  all  secured  in  their 
places,  by  pins  under  them  in  the  up- 
rights of  the  treble  rooms  :  and  a  room 
.  will  of  course  hold  more  or  less  of  the  dif- 
ferent layers  of  trebles,  according  as  the 
sheets  of  paper  are  smaller  or  larger. 

The  drying  loft  is  furnished  around., 
with  sliding  lattice  shutters,  so  as  to  be 
closed  or  opened,  as  occasion  requires, 
rooms,  each  room  being  12  by  15  or  18  <  These  windows  or  shutters,  extend  from 
feet,  according  to  the  breadth  of  the  loft,  j  the  top  to  near  the  bottom  of  the  room  ; 
If  the  building  is  very  wide,  the  treble  !  and  form  the  sides  of  the  loft.  They  are 
rooms  are  set  double,  that  is,  two  sets  of  {  closed,in  all  weather  adverse  to  the  drying 
them  running  through  the  length  of  the  j  of  the  paper,  or  when  the  wind  is  too  high, 
loft,  with  a  passage  between  them.  j  and  especially  when  the  sized  paper  is 

The  room's  being  thus  formed  of  the  j  hung.  When  the  paper  is  dried,  the  tre- 
uprights,  the  trebles  to  hold  the  paper  .  bles  are  brought  down  in  succession,  and 
are  hung  on  them  as  follows  :  the  trebles  J  the  paper  taken  from  them  and  rested  in 
consist  of  a  light  piece  of  scantling  simi- 1  heaps,  in  one  side  of  the  room,  ready  to 
lar  to  the  frame  of  the  side  of  a  bedstead,  jgo  to  to  the  sizing  room, 
and  bored  in  the  same  manner,  and  hung  i    The  trebles  as  they  are  taken  down,  arc 


, 5*  otherwise  insecure;  but  if  wet  windy 
weather,  it  must  be  piled  away  to  wait ; 
or  if  it  be  like  to  be  freezing  weather  in 
the  winter,  all  fine  papers  will  be  injured, 
if  hung;  but  printing  and  copperplate  pa- 
pers will  not  injure :  and  it"  the  papers 
are  of  dark  shades,  the  frost  will  contri- 
bute much  to  whiten  them. 

Ow  ing  to  the  winter  weather  and  frost, 
it  is,  (on  account  of  the  packs,)  an  object 
with  the  manufacturer  to  make  consider- 
able lots  of  thin  post  papers,  the  packs 
not  being  so  large  as  of  the  thick  papers, 
they  do  not  accumulate  to  so  great  a 
bulk,  and  they  dry  sooner  when  hung  in 
the  spring. 

The  drying  Loft. 
This  room,  being  generally  the  upper 
story  of  a  mill,  is  about  14  to  16  feet  high, 
furnished  with  upright  posts  in  pairs,  at 
about  12  feet  space  from  each  other, 
along  each  side  of  a  room,  and  leaving  a 
passage  between  a  row  of  posts  and  the 
side  of  the  room  :  the  distance  from  the 
uprights  to  each  other,  across  the  loft,  is 
about  15  to  18  feet ;  and  this  space  forms 
the  area  of  what  is  called  the  treble 


with  cords  ;  that  is,  a  piece  of  scantling 
holds  the  cords  reeved  through  the  holes 
to  the  opposite  treble,  and  w  hen  extended, 
the  ends  of  each  piece  rest  against  the 
uprights,  to  prevent  the  cords  s wagging 
across  from  one  to  the  other.  The  holes 
and  cords  extend  across  at  about  a  distance 
from  each  other  of  8  inches  ;  and  when 
thus  placed,  are  pushed  up  to  about  the 
height  of  a  man's  head,  and  secured  there 
by  a  pin  under  them,  in  a  hole  in  the  up- 
right, and  are  ready  to  receive  the  paper, 


rolled  up  and  put  on  a  low  bench,  in  one 
side  of  the  loft. 

In  some  fine  mills,  curtains  are  hung 
round  the  shutters  in  the  cold  weather,, 
and  by  this  means,  the  drying  goes  on 
much  longer,  than  when  the  loft  is  more 
open. 

,  The  paper  when  dry,  leaves  this,  for  the 
sizing  room,  it  is  however  previously  jog- 
ged, (as  the  workmen  term  it,)  which  "is 
pressing  it  against  the  breast,  so  as  to  get 
it  free  from  turning  up  into  hollow  spaces, 


The  paper,  when  hoisted  up  in  the  wet  >  as  it  comes  off  the  lines,  and  where  it  re 
packs,  is  placed  on  the  floor,  and  one  I  ceived  the  shape  in  which  it  is  hung  while 


pack  at  a  time  on  the  table.  The  table  is 
furnished  with  wheels,  and  is  easily  push- 
ed about  all  over  the  loft,  as  the  lofts  man 
requires  it.  The  paper  is  then  hung  by 
a  few  sheets  of  thick  and  rather  more  of 
thin  paper,  lifted  from  the  pack  by  the 


drying. 


Sizing  Room. 


This  room  contains  a  press,  various 
tubs,  boxes,  &c.  for  holding  the  size,  and 


loftsman  with  his  left  hand  taking  hold  of  for  sizing  the  paper ;  and  the  cocks  or 
the  corner,  and  slipping  under  the  sheets,  ;  pipes  from  the  sizing  and  water  kettles, 
a  cross  in  the  form  of  a  T,  over  which  the  t  ought  to  open  into  the  adjoining  kettle 
paper  hangs,  and  he  puts  it  up,  passing  j  room,  which  contains  the  kettles  and  s* 


PAF 


PAP 


pump ;  or  If  possible,  a  free  pipe  of  clear 
water. 

The  size  kettle  ought  always  to  be 
made  of  copper,  of  about  2  to  300  gallons, 
about  equally  deep  and  broad,  and  the 
fire  place  for  the  kettle,  ought  to  be  con- 
structed on  the  outside  of  the  building  ;  a 
window  should  be  near  it,  to  draw  off  the 
steam,  and  to  allow  the  refuse  of  the  pieces 
to  be  thrown  out,  after  boiling. 

An  iron  kettle  of  about  100  gallons, 
ought  to  be  set  in  a  similar  manner  for  hot 
water,  and  a  pump  to  supply  it;  the 
size  is  made  from  the  skins,  and  also  from 
the  feet  of  animals ;  the  former  far  pre- 
ferable to  any  thing  else,  and  we  believe 
the  best  and  the  cheapest,  is  that  from 
the  hides,as  bought  by  the  tanners,though 
at  first,  of  much  higher,  cost ;  if  any  can 
be  had,  which  may  be  worm  eaten,  as  is 
often  the  case,  something  may  be  saved 
in  the  price ;  the  hides  ought  always  to  be 
limed,  to  take  off  the  hair,  and  they  are 
then  ready  for  soaking   tor  the  kettle. 

The  size  is  prepared  from  about  200 
pounds  of  hides,  boiled  down  for  about 
twenty-four  hours,  regularly  kept  at  the 
boiling  point  ;  the  kettle  is  previously 
prepared,  by  putting  in  it  a  bottom  of 
straw,  and  over  it  a  wooden  lattice  frame, 
which  prevents  the  size  from  adhering  to 
the  parts,  where  the  fire  acts,  and  being 
burnt :  the  pipe  to  the  cock  is  likewise 
filled,  with  a  small  birch  broom,which  pre- 
vents the  pieces  from  being  drawn  into  it, 
in  running  off  the  size.  We  have  heard 
of  the  size  being  boiled  in  a  hair  bag,  but 
it  is  not  in  general  use. 

When  the  size  is  sufficiently  boiled, 
which  is  discovered  by  the  sinking  of  the 
pieces,  to  the  bottom  of  the  kettle,  it  may 
be  drawn  off  into  casks,  and  is  ready 
for  use  ;  when  used  it  is  returned  into 
the  kettle,  and  warmed  by  a  gentle  fire, 
is  drawn  off  by  the  cock  into  the  sizing 
box,  by  a  long  trough,  having  in  it  several 
slides,  with  fine  wire,  through  which  the 
size  is  strained  in  its  passage,  and  seve- 
ral masses  of  alum,  are  placed  along  the 
trough,  which  preserves  the  size,  and 
hardens  its  effect  on  the  paper,  and  which 
the  hot  size,  melts  in  its  passage  ;  a  bag 
is  also  placed  at  the  end  of  the  trough, 
and  the  size  is  again  strained  through  it, 
into  the  sizing  box. 

The  sizing  box  in  which  the  paper  is 
wet,  is  an  oblong  square,  about  4^  by  3 
feet,  and  18  inches  deep  ;  it  is  fixed  on  the 
right  hand  side  of  the  press,  with  its  end 
near  the  press-posts ;  the  sizer  leans 
over  the  box,  and  taking  a  conveni- 
ent handful  of  the  paper,  brought  from 
the  loft  in  his  right  hand,  about  the  mid- 
dle, opens  the  bottom  of  the  paper,  with 


his  left  hand,  like  rusling  the  leaves  of  a 
book,  at  the  same  time,  lowering  it  into 
the  box,so  as  to  introduce  the  size  into  the 
paper :  the  right  hand  ought  to  grasp  the 
paper,  first  having  two  wooden  slices  like 
rulers,  between  it  and  the  paper ;  when 
the  paper  is  lowered  into  the  size,  it  will 
remain  a  short  time  without  opening,  and 
may  be  taken  up  by  the  opposite  end,  and 
the  same  again  loosened,  to  get  the  size 
into  it  in  the  same  manner  ;  after  this,  it 
may  be  left  floating,  or  rather  till  it  sinks 
in  the  size,  which  if  it  takes  the  size,  it 
will  do  in  a  short  time;  it  is  then  to  be 
lifted  out  by  a  slice  at  each  end,  and  hand- 
ed over  to  the  press,  and  laid  in  succes- 
sion as  many  handfuls  as  it  will  hold  con- 
veniently. In  the  bottom  of  the  press  is 
put  a  box  to  catch  the  size,  which  runs 
from  the  paper,  and  having  a  hole  in  it 
near  the  bottom,  a  bucket  is  put  under  the 
hole,  and  the  size  is  caught,  and  returned 
into  the  size  kettle.  The  temperature  of 
the  size,  is  also  an  object  of  great  conse- 
quence, it  ought  to  be  generally  as  warm 
as  the  hand  can  bear;  too  great  heat 
is  apt  to  dissolve  the  paper,  and  break  it 
very  much,  if  too  cold,  it  is  very  apt  to 
size-stain,  which  is  ruinous  to  it. 

It  is  to  be  remarked  here,  that  it  is  much 
better  to  have  the  size  continually  run- 
ning, into  the  sizing  box,  while  the  paper 
is  absorbing  it,  as  the  paper  takes  up  a 
large  quantity  of  glutinous  matter,  and  if 
the  box  is  not  supplied,  the  size  becomes 
weak  ;  it  is  also  of  advantage  to  keep  the 
size  in  the  kettle  hot,  it  would  other- 
wise cool  too  much.  When  the  press 
is  filled  the  paper  must  be  pressed,  and 
this  screw  should  be  cut  so  as  to  fly, 
and  to  have  a  lock  like  the  vat  presses. 
When  the  paper  is  moderately  pressed, 
at  the  sides,  it  should  be  well  washed 
down  all  round,  with  hot  water,  which 
prevents  the  edges  from  drying  and  glue- 
ing together ;  the  press  is  then  knocked 
off,  and  the  paper  taken  out,  and  taken 
into  the  workhouse  to  be  parted;  as 
it  must  be  parted  before  it  becomes  cold ; 
it  ought  to  be  covered  with  a  cloth  to 
keep  it  warm,  until  it  is  parted,  when 
parted  it  ought  to  stand  in  packs,  till  it  is 
cold  before  it  is  hung,  because  otherwise 
the  size  is  apt  to  evaporate  or  fly  off,  and 
when  hung,  the  air  should  be  very  gentle, 
as  a  breeze  of  wind  will  stain  it,  and  if 
the  wind  blows  strong,  the  size  will  be 
driven  off  entirely;  when  cold  it  ought  to 
be  taken  to  the  loft  without  delay,  as  it  is 
subject  to  putrefaction  ;  and  hung  in  the 
same  manner  as  described  for  water-leafs. 

The  sizing  is  the  most  difficult  of  the 
whole  process,  of  paper  making,  and  the 
most  subject  to  accidental  loss;  the  size  if 


FAP 


PAP 


not  made  wholly  from  sound  skins,  will 
not  render  the  paper  fit  for  writing,  and 
one  skin  will  injure  the  whole  mass ;  the 
heat  of  the  summer,  or  cold  of  the  winter, 
are  equally  ruinous  to  the  operation,  and 
wet  retards  it ;  frosts  ruin  the  paper  alto- 
gether if  sized ;  and  paper  if  sized  secure- 
ly, during  the  heat  of  summer,  is  never 
hardened  till  the  cold  of  the  fall,  or  win- 
ter. We  may  here  also  recommend,  that 
in  hot  weather  when  the  size  is  drawn  off, 
into  casks  or  tubs,  it  has  lately  been  dis- 
covered, that  if  about  half  a  handful  of 
finely  powdered  rosin  is  strewed  over  it, 
the  size  will  keep  for  a  long  time. 

When  the  sized  paper  is  dried  in  the 
loft,  it  is  to  be  taken  down  and  brought 
into  the  salle,  or  finishing  room. 

Salle  or  Finishing  Room. 

This  room  is  generally  the  best  and 
most  extensive  part  of  the  mill ;  it  is  fur- 
nished with  the  dry  presses,  perhaps  five 
or  six,  and  with  benches  round,  for  the 
paper  pickers  and  sorters ;  the  foreman 
of  the  mill  has  his  station  in  this  room,  as 
has  also  the  finisher ;  paper  when  com- 
menced to  be  finished  is  to  be  pressed, 
which  discovers  the  knots  and  it  also 
smooths  the  surface,  it  is  then  delivered 
over  by  weight  to  the  women,  who  pick 
it;  a  certain  weight  (differing  in  each  size 
and  kind  of  paper,)  forming  a  days  work  ; 
the  specks,  knots  and  moats,  are  here 
picked  out  of  the  sheets,  and  with  as  little 
injury  to  the  surface  as  possible,  the  wo- 
men for  this  purpose,  ought  to  have  a  very 
sharp  knife,  and  it  ought  to  be  held  much 
like  a  pen  is  held,  but  at  the  same  time 
the  middle  finger  ought  to  have  a  fine  po- 
lished thimble,  in  order  to  smooth  any 
places,  which  in  turning  up  the  knots  be- 
come frayed.  When  all  the  sheets  are 
thus  gone  over,  the  paper  is  considered 
picked,  and  is  ready  lor  the  sorters.  The 
business  of  sorting,  consists  in  looking 
over  the  paper  sheet  by  sheet,  and  laying 
out  all  the  imperfect  sheets,  into  the  seve- 
ral parcels,  which  are  as  follows. 

1st.  The  whole  paper  which  is  consi- 
dered now  free  from  casualty  may  go  into 
the  hands  of  the  finisher. 

2d.  The  retrea,  or  defective,  is  that 
which  has  received  accidents  in  the  course 
of  the  manufacture.  It  has  frequently 
drops  at  the  vat,  frays,  blisters,  or  hems 
of  the  coucher,  rents,  fractures,  or  peeling 
of  the  parters,  pulling  off  the  corners,  and 
wrinkles  of  the  hanging.  When  the  pa- 
pers are  sized,  all  these  accidents  may 
again  occur,  together  with  the  stains  of 
the  sizing,  and  the  mildew.  The  knives 
of  the  pickers  are  very  injurious  in  making 
holes  in  the  paper,  and  otherwise  injuring 


its  surface.  When  these  delects  are  very 
obvious,  the  paper  is  sorted  into  a  second 
or  inferior  retrea. 

3d.  The  broken,  is  when  the  sheets  are 
much  fractured  or  injured  in  any  part  of 
the  manufacture. 

After  the  several  sorts  of  paper  are 
placed  out,  the  finisher  puts  them  into  the 
dry  presses,  where  they  are  pressed  for 
several  days,  the  longer  and  harder  the 
better,  and  the  surface  is  astonishingly 
improved  and  polished  by  it. 

The  paper  is  then  taken  out  for  tying 
up,  for  which  purpose  it  is  told  out,  as  it 
is  called,  into  quires  of  24  sheets.  The 
man  does  this  by  turning  up  the  left  hand 
corner  of  a  few  sheets  of  the  pack  by  a 
twist  of  his  left  hand,  and  opens  them, 
counting  out  24  sheets,  by  taking  a  num- 
ber of  four  of  them  in  succession  betw  een 
the  fingers  of  his  right  hand,  and  when  he 
thus  counts  the  required  number,  (almost 
mechanically)  lays  the  quire  flat  on  the 
table,  and  the  succeeding  quire  on  it, only 
a  little  further  back;  by  this  means  he 
keeps  them  all  ready  for* folding  when  he 
has  a  ream  of  twenty  quires,  or  rather  of 
eighteen  quires  of  perfect,  and  two  quires 
of  broken,  (one  at  each  side,)  which  are 
always  put  up  for  a  ream. 

It  has  been  for  some  time  the  practice, 
to  put  up  all  the  papier  in  half  quires,  as 
the  sheets  lay  much  better,  and  make  a 
neater  ream. 

We  mentioned  in  the  day's  work  of  the 
vat,  that  a  post  consisted  of  five  quires, 
or  125  felts  :  this  allows  one  sheet  in  evey 
quire  for  loss  in  the  process;  and  with 
good  workmen  it  is  sufficient ;  but  most, 
generally,  in  England,  twenty-six  sheets 
are  made  for  a  quire,  or  130  for  a  posts 
and  it  ought  to  be  the  same  in  America  - 
but  the  custom  has  obtained,  and  from 
this  an  extra  quantity  of  paper  always  ia 
lost,  and  our  reams  do  not  turn  out  in 
finishing  full  tale  to  the  account  for  which 
the  workmen  are  paid. 

Whenever  the  paper  comes  round  so 
whole,  as  not  to  make  up  the  two  quires 
in  the  ream  of  broken,  18  sheets  of  retrea 
are  substituted,  or  16  sheets  of  whole  pa- 
per in  each  of  the  outside  quires,  which 
is  a  great  saving  to  the  mill. 

When  the  quires  are  folded  and  placer! 
on  each  other  to  form  the  ream,  they  are 
again  pressed  hard,  with  a  lay  board  be- 
tween each  ream,  or  if  small  paper,  seve- 
ral reams  are  laid  on  one  board  along  side 
of  each  other,  as  convenient.  When  they 
are  thus  pressed,  they  are  brought  again 
to  the  finishing  bench,  the  wrapper  is  put 
round  them,  they  are  tied  with  a  cord  and 
they  are  sent  to  market. 

YAPc.il,  Alar  btipg of.  See  Marbling. 


PAP 


PAR 


PAPER  MARL.  See  Agriculture 
article  Marl. 

PAPIN'S  DIGESTER — In  order  to  (lis 
solve  solid  animal  substances,  either  par 
tially  or  totally,  a  vessel  or  apparatus  is 
employed  which  has  been  invented  by  Pa 
pin.  It  is  made  of  strong1  metal,  to  the 
thickness  of  an  inch.  The  inner  bottom 
has  an  oval  shape,  as  is  seen  in  the  figure 


A  conical  lid  is  fitted  in  by  grinding,  and 
kept  down  air-tight  by  the  cross  bar  and 
screw,  a,  b.  Several  improvements  have 
been  made  in  this  machine,  which  will  be 
presently  noticed. 

After  putting  meat  into  the  digester, 
together  with  a  sufficient  quantity  of  wa- 
ter, a  lid  is  closely  screwed  or  fastened 
on,  so  as  to  admit  no  external  air.  By  a 
moderate  fire,  the  meat  will,  in  the  course 
of  six  or  eight  minutes,  be  reduced  to  a 
perfect  pulp;  by  augmenting  the  heat  of 
the  fire,  or  extending  the  time  of  diges- 
tion, the  hardest  bones  may  be  converted 
into  a  pulp  or  jelly.  This  effect  is  pro- 
duced by  the  most  perfect  closure  of  the 
\'essel,  which  prevents  the  access  or  es- 
cape of  air,  so  that  the  reverberations  oc- 
casioned by  the  expansion  of  the  aerial 
fluid,  dissolve  the  whole  into  an  uniform 
body,  and  mix  the  aqueous,  saline,  olea- 
ginous, and  other  particles  so  strongly  to- 
gether, that  they  cannot  be  easily  sepa- 
rated, but,  while  hot,  appear  one  liquor, 
arid,  when  cold,  form  a  jelly  of  a  strength 
proportionate  to  the  quantity  of  flesh  or 
bones  dissolved  in  the  water. 

This  useful  instrument  has  not  been 
hitherto  applied  to  culinary  purposes ; 
though  within  the  last  two  years  an  im- 
perfect imitation  of  it  has  been  vended  in 
the  shops  ;  and  we  state  with  satisfaction, 
that  even  the  latter  is  incomparably  more 
economical  than  the  various  kinds  of  stew- 
pans  formerly  employed.  Cast-iron  diges- 
ters are  manufactured  of  various  sizes  and 
prices. 

Wilk  has  given  an  improvement  of  the 
digester  in  the  Swedish  Phil.  Trans,  vol. 
xxxiv.  Messrs.  Jackson  and  Moser  hav*e 
added  to  it  a  safetv  valve. 


PARCHMENT  GLUE.  See  Ge la- 
tin. 

PARCHMEN  T.  In  treating  of  grained 
parchment,  under  the  article  manufacture 
of  grained  parchment,  and  on  one  or  two 
other  occasions,  it  was  mentioned,  that 
parchment  was  nade  of  the  skins  of  sheep 
or  goats, so  as  to  be  subservient  to  the  pur- 
poses of  binding  books,  the  reception  of 
ink,  &c.  On  the  manufacture  of  parch- 
ment, the  following  observations  are  given 
by  Dr.  Wiliich. 

The  wool  is  first  stripped  off  the  skins, 
which  are  plunged  in  a  lime-pit,  for  the 
space  of  24  hours,  then  taken  out,  drained, 
and  stretched  on  a  kind  of  frame  ;  when 
the  flesh  is  scraped  off  by  means  of  an  iron 
instrument.  Next,  they  are  moistened 
with  a  wet  rag,  then  sprinkled  with  pul- 
verized chalk,  rubbed  with  a  pumice- 
stone,  and  afterwards  with  the  instrument; 
when  the  skins  are  again  moistened,  rub- 
bed with  the  pumice-stone,  drained,  and 
the  iron  instrument  is  passed  a  third  time 
over  them.  The  wool,  or  hair-side,  un- 
dergoes similar  operations  ;  and  the  whole 
being  carefully  extended  on  the  frame, 
the  flesh-side  is  again  scraped  :  when  it  is 
a  second  time  sprinkled  with  pulverized 
chalk,  which  it  is  afterwards  gently  brush- 
ed off!,  and  the  skin  again  suspended,  that 
it  may  become  perfectly  dry. 

The  next  operation  is  that  of  paring ; 
when  the  skins  are  reduced  to  one  half 
of  their  thickness  ;  and  rendered  smooth 
by  the  action  of  the  pumice-stone.  The 
parings  are  consumed  in  making  size, 
glue,  &c.  while  the  skin  is  employed  for 
engrossing  deeds,  and  other  purposes. 

There  is  a  finer  sort  of  parchment, 
known  under  the  name  of  vellum,  which 
s  prepared  from  the  skins  of  sucking- 
calves.  It  is  manufactured  in  a  similar, 
manner,  with  the  first  mentioned  article, 
excepting  that  it  is  not  immersed  in  the 
lime-pit.  A  very  excellent  glue,  or  ce- 
ment,may  be  obtained  by  boiling  the  same 
shreds  of  vellum,  so  as  to  convert  them 
into  a  jelly  ;  but  care  should  be  taken 
that  no  fragments  of  parchment  be  used, 
because  the  skins  of  goats  and  sheep  are 
unfit  for  such  purpose. 

A  patent  was  lately  granted  to  Mr.  • 
Hitchcock,^r  converting  old  skins  of  parch- 
ment or  vellum  into  leather.  Although  we 
doubt  the  practical  tendency  of  the  paten- 
tee's ingenious,  but  complicated  proces- 
ses ;  yet,  in  the  present  instance,  as  they 
may  be  applied  to  other  useful  purposes, 
we  shall  observe,  that  he  endeavours  first 
to  reduce  the  skins  to  their  natural  state, 
by  washing  them  well  and  often  in  water 
for  24  hours  ;  then  removing  them  for  a 
similar  time,  to  a  bath  composed  of  one 


PAR 


PAl 


and  an  half  pounds  of  white  vitriol,  one 
md  of  cream  of  tartar,  and  one  ounce 
of  sal  ammoniac,  dissolved  in  20  gallons  of 
w  ater.  In  order  to  soften  their  texture, 
and  to  discharge  the  lime  he  adds  to  this 
liquor,  ten  pounds  of  oil  of  vitriol,  one 
pound  of  aqua-fbrtis,  and  one  pint  of  spirit 
of  salt ;  in  which  acid  bath,  the  skins  are 
to  be  steeped  only  for  a  short  time.  After 
washing  them  properly,  rinsing  out  all  the 
acid,  and  completely  wringing  out  the 
water,  without  tearing  the  skins,  they  are 
to  be  immersed  and  well  soaked,  in  a  tan- 
ning liquor,  composed  of  twenty  pounds 
of  oak-bark,  seven  pounds  of  sumach,  five 
pounds  of  elm-bark,  three  pounds  of  sas- 
safras, and  the  same  quantity  of  lignum- 
vitx  shavings,  mixed  with  20  gallons  of 
water  previously  warmed,  (probably  boil- 
ed,) for  12  hours,  and  cooled  to  the  tem- 
perature of  new  milk,  before  the  skins  are 
immersed.  Next,  they  are  to  be  tanned 
in  the  common  way,  with  oak -bark,  or  oak 
and  sumach,  then  washed  and  dried. — 
Lastly,  to  make  the  renovated  leather  wa- 
ter-proof, it  should  first  be  soaked  for  live 
or  six  days  in  linseed  or  nut-oil ;  and,  af- 
ter wringing  out  the  superfluous  oil,  the 
skin  ought  to  be  repeatedly  dressed  with 
the  following  composition :  take  seven 
pounds  of  nut,  or  linseed-oil ;  red  lead, 
litharge,  sugar  of  lead,  white  vitriol,  bees- 
wax, resin,  and  pitch,  one  pound  of  each  • 
melt  them  together  over  a  moderate 
fire. 

The  preservation  of  deeds  written  on 
parchment,  is  an  object  that  has  ever  en- 
gaged the  attention  of  the  lawyer  and  the 
antiquary  :  it  is  of  still  greater  importance 
to  those  who  hold  estates,  or  other  tene- 
ments, in  order  to  enable  them  to  peruse 
such  papers,  as  have  been  kept  for  a  series 
of  years,  and  which,  from  moisture,  or 
other  causes,  are  almost  illegible.  To  fa- 
cilitate this  desirable  object,  we  select  the 
f  ollowing,  as  being  the  most  simple  of  the 
many  recipes  which  have  been  recom- 
mended :  immerse  the  parchment  oblite- 
rated by  time,  into  a  vessel  of  cold  water, 
fresh  drawn  from  a  well ;  in  the  space  of 
a  minute,  it  should  betaken  out,  and  press- 
ed between  two  blotting  papers,  to  pre- 
vent it  from  shrivelling,  while  it  is  drying. 
As  soon  as  it  is  moderately  dry,  (if  the 
characters  be  not  legible)  the  operation 
should  be  repeated,  two  or  three  times. 
Thus,  the  skin  will  resume  its  pristine  co- 
lour, and  appear  throughout  alike. 

PARCHMENT  GRAINED.  See  ma- 
jiufacture  of  Grained  Parchment. 

PARIAN  MARBLE.     See  Marble. 

PARING  OF  LAND.  See  Ac ri cul- 
ture. 


PAINT,  MILK.    See  Colour  Mai. 

INC. 

PAINTS,  spots  of,  how  removed.  The 
use  of  certain  agents  for  the  removal  of 
oil,  or  spots  of  grease,  &.c  may  be  also  em- 
ployed for  the  removal  of  spots  of  paint. 
The  marks  of  white  paint,  in  particular, 
may  be  discharged  by  moistening  or  rub- 
bing, the  spot  or  stain  with  spirit  of  tur- 
pentine, or  sulphuric  ether, 

PAINT.  In  February  1799,  a  patent 
was  granted  to  Mr.  Joseph  Tkhnarsh, 
for  his  invention  of  a  compound,  which 
may  be  either  substituted  for  paint,  or 
mixed  with  other  pigments,  for  enlarging 
their  quantity,  or  reducing  their  price. 
The  patentee  directs  the  following  articles 
to  be  pulverised,  namely  ;  glass,  burnt 
clay,  the  slag  of  glass,  copper,  iron,  or 
other  manufactories ;  marble,  spar,  flint, 
or  similar  vitrefiable  or  calcareous  earths. 
The  powders,  thus  obtained,  may  be  em- 
ployed as  a  paint,  with  the  liquids  com- 
monly used  in  mixing  colours  ;  or  they 
may  be  immediately  incorporated  with 
any  kind  of  paint. 

The  following  preparation,  however, 
appears  to  be  more  simple,  and  is  equally 
efficacious  ;  it  was  first  published  in  the 
"  Bibliotheqae  Physico-economtque?  for 
1792,  by  M.  Ludicke  ;  who  has  employed 
it  with  great  success  for  painting  ceilings, 
gates,  doors,  and  even  furniture.  He  di- 
rects fresh  curds  to  be  bruised  in  an  ear- 
then pan,  or  in  a  mortar ;  after  which  they 
must  be  mixed  with  an  equal  portion  of 
slacked  lime  :  the  result  will  be  a  white 
fluid,  that  may  be  applied  with  as  much 
facility  as  varnish  ;  but  it  will  be  neces- 
sary to  employ  such  mixture  on  the  same 
day,  as  it  dries  very  speedily,  and  is  apt 
to  become  too  thick,  if  it  be  kept  24  hours. 
He  observes  that  Armenian  bole,  ochre, 
and  all  pigments  that  are  miscible  with 
lime,  may  be  incorporated  in  various  pro- 
portions, according  to  the  colour  to  be 
communicated ;  but  some  caution  is  ne- 
cessary, in  making  such  addition,  to  use 
the  smallest  possible  quantity  of  water ; 
as  the  painting  will  otherwise  be  less  du- 
rable. 

When  two  coats  of  this  paint  have  been 
applied,  it  may  be  polished  with  a  piece 
of  woollen  cloth,  or  other  proper  sub- 
stance ;  in  consequence  of  which,  it  will 
become  as  bright  as  any  varnish  ;  and  if 
the  ceiling,  &c.  be  exposed  to  moisture,  it 
should  be  coated  with  the  whites  of  eggs ; 
by  which  expedient,  it  will  become  as  du- 
rable as  oil  painting1.  The  principal  ad- 
vantages, derived  from  the  use  of  this  sub- 
stitute, consist  in  its  cheapness,  and  the 
facility  with  which  the  two  coats  may  be 


PAl 

applied,  and  polished ;  one  day  being  suf- 
ficient for  both  operations.  Hence,  it  de- 
serves the  attention  of  those  whose  lungs 
cannot  support  the  disagreeable  smell, 
arising  from  oil  paint ;  and  who  are  not 
disposed  to  encourage  the  extravgant 
charges  of  the  house-painters. 

Besides  the  observations  we  have  given 
on  colours,  (see  Colours)  the  following 
additional  remarks  may  be  useful. 

A  Green  Paint  for  inside  malls. 

Take  four  pound  of  Roman  vitriol  (blue 
stone)  and  one  pound  of  Spanish  whiting. 
Put  tiiese  ingredients  (being  pi-eviously 
bruised  together,)  into  an  earthen  vessel, 
and  pour  on  them  some  warm  rain  or  soft 
water.  Simmer  this  over  a  slow  fire  for 
three  hours,  occasionally  stirring  it  with 
a  stick.  Take  it  off  and  let  it  stand  ;  in 
24  hours  the  ingredients  will  subside,  and 
the  water  become  clear.  Pour  off  the 
water,  and  in  this  state  it  will  keep  for 
years,  ready  to  mix  for  use  at  pleasure. 
When  wanted,  it  must  be  mixed  with  wa- 
ter, wherein  a  small  portion  of  glue  has 
been  dissolved,  and  laid  on  the  walls,(one, 
two,  or  three  coats)  as  may  seem  neces- 
sary. Twelve  pounds  of  vitriol,  and  four 
pounds  of  whiting,  will  give  four  coats 
to  a  wall,  40  feet  by  24,  and  produce  a 
lively  and  refreshing  green. 

The  following  composition  is  recom- 
mended for  colouring,  and  preserving- 
gates,  pales,  barns,  roofs,  and  timber  ge- 
nerally, from  the  weather. 

Melt  twelve  ounces  of  resin,  in  an  iron 
pot  or  kettle,  add  three  gallons  of  train 
oil,  and  three  or  four  rolls  of  brimstone  ; 
when  they  are  melted  and  become  thin, 
add  as  much  Spanish,  brown  or  red  or 
yellow  ochre,  (or  any  other  colour  you 
like,  ground  fine  as  usual  with  oil)  as  will 
give  the  whole  the  shade  wanted.  Then 
lay  it  on  with  a  brush,  as  hot  and  as  thin 
as  you  can.  Some  days  after  the  first  coat 
is  dried,  lay  on  a  second. 

It  is  well  attested,  that  this  will  pre- 
serve plank  for  years,  and  prevent  the 
weather  from  driving  through  brick 
work. 

Another  composition.  Take  three  parts 
of  slacked  lime,  two  of  wood-ashes,  and 
one  of  fine  sand,  or  stone  coal  ashes  ;  sift 
these  through  a  fine  sand  sieve,  and  add 
as  much  linseed  oil,  as  will  bring  it  to  a 
consf&eroce  for  working,  with  a  painter's 
brush  ;  great  care  must  be  taken  to  mix 
the  ingredients  perfectly.  Two  coats  are 
necessary  ;  the  first  may  be  thin,  the  se- 
cond as  thick  as  can  conveniently  be  work- 
ed. 

PAINTING  IN  DISTEMPER.  Pro- 
posed as  an  advantageous  substitute  for  a 


PAl 

new  kind  of  paint,  prepared  by  M.  Carbo* 
nell. 

It  is  well  known  that  a  disagreeable 
smell  is  perceived,  on  entering  apartments 
newly  painted  in  distemper  ;  therefore, 
till  such  apartments  have  been  some  time 
exposed,  to  the  contact  of  the  air,  no  one 
likes  to  inhabit  them.  The  following 
process  remedies  these  two  inconvenien- 
ces. 

The  method  of  operation  is  very  simple- 
it  consits  in  substituting  the  serum  of 
beef-blood,  instead  of  size,  which  is  usu- 
ally employed  to  dilute  the  colouring  mat- 
ter. 

1.  The  butcher  must  be  requested  to 
catch  the  blood,  of  one  or  more  oxen  in 
clean  vessels.  When  the  blood  is  become 
quite  cold,  that  is,  in  about  three  or  four 
hours  after  it  has  been  drawn,  the  vessels 
are  gently  inclined,  and  by  these  means, 
a  transparent  liquid  is  poured  off,  which 
has  a  slight  smell  of  amber.  It  is  strain- 
ed through  a  piece  of  linen,  to  separate 
from  it  the  particles  of  blood,  that  may  be 
detached  and  mixed  with  it. 

2.  Some  quicklime,  upon  which  has 
been  thrown  a  very  small  quantity  of  wa- 
ter only,  for  the  purpose  of  diminishing 
the  adhesion,  of  its  integral  parts,  must 
be  reduced  to  powder.  This  powder  is 
sifted,  and  it  is  instantly  put  away  in  boxes 
or  bottles,  very  carefully  closed. 

3-  When  the  two  above  mentioned  ma- 
terials are  to  be  used,  the  serum  must  be 
poured  into  a  wooden  or  earthen  vessel, 
and  a  sufficient  quantity  of  the  pulverixed 
lime  added,  to  give  the  mixture  such  a 
degree  of  liquidity,  as  to  be  easily  spread 
with  the  brush  over  the  surfaces,  that  are 
to  be  covered  with  it. 

4.  Too  great  a  quantity  of  this  paint, 
must  not  be  prepared  at  once,  for  it  very 
quickly  becomes  thick;  and  when  it  has 
too  much  consistence,  it  cannot  be  used. 
This  inconvenience  is  prevented,  by  keep- 
ing it  always  at  the  same  degree  of  fluidi- 
ty, by  the  addition  of  a  sufficient  quantity 
of  serum,  which  should  constantly  be  kept 
near  the  vessel  with  the  paint,  to  be  used 
as  occasion  requires. 

5.  The  colour  when  in  this  state  should 
be  laid  on  as  speedily  as  possible. 

6.  As  the  colour  resulting  from  the  ap- 
plication of  ibis  preparation,  is  always 
white,  and  one  may  sometimes  wish  to 
have  a  different  colour,  it  is  produced  by 
ochreous, earths  of  the  red,  yellowback, 
or  green  kinds.  A  beautiful  blue  colour 
may  likewise  be  obtained,  by  employing 
blue  glass,  made  with  the  oxyd  of  cobalt, 
provided  the  glass  be  reduced,  to  an  im- 
palpable powder. 

7.  As  the  addition  of  coloured  ochreous 


i»AI 


PAT 


Hulciuils,  must  necessarily  weaken  the 
composition,  it  may  be  kept  at  the  same 
degree  of  solidity,  by  adding-  a  few  whites 
of  eg*g,  to  the  serum  employed  for  dilut- 
ing the  composition;  but  care  must  be 
taken,  not  to  add  too  large  a  quantity, 
otherwise  the  paint  would  be  liable  to 
.scale  off. 

8.  This  kind  of  paint,  can  only  be  ap- 
plied on  wood  or  plaster,  which  have  not 
been  previously  covered  with  oil  paint. 

9.  As  a  single  coat  is  not  sufficient,  two 
or  three  may  be  laid  on,  when  the  work 
is  required  to  be  performed  correctly ; 
but  before  a  fresh  coat  is  given,  the  for- 
mer must  be  perfectly  dry. 

10.  This  paint  is  capable  of  taking  a 
beautiful  polish  by  friction,  like  any  other 
kind  ;  but  it  is  preferable  to  dip  the  cloth, 
with  which  it  is  rubbed,  in  spermaceti 
rather  than  any  other  kind  of  oil. 

It.  For  diluting  white  or  coloured  paint, 
only  fresh  serum,  which  has  undergone 
no  alteration,  must  be  employed;  other- 
wise the  paint  would  be  of  a  worse  quality, 
and  less  permanent. 

Many  precautions  are  necessary,  parti- 
cularly in  summer,  for  keeping  the  serum, 
because  this  fluid  is  very  strongly  dispos- 
ed to  putridity.  It  is  therefore  essential 
1 6  keep  it  in  a  cool  place,  and  to  examine, 
before  it  is  employed,  whether  it  does  not 
begin  to  smell  disagreeably ;  for,  in  that 
case ,  it  must  not  be  used. 

For  the  same  reason,  care  must  be  taken 
to  keep  the  vessels  clean,  in  which  the  se- 
rum is  preserved,  and  to  wash  them  often 
with  warm  water,  to  remove  the  altered 
particle  of  the  fluid,  with  which  the  sides 
of  the  vessel  may  be  impregnated. 

M.  Carbonell  asserts,  that  this  paint  is 
permanent,  when  prepared  with  good  ma- 
terials ;  it  may  even  be  employed  for 
painting  damp  walls,  without  fear  of  its 
being  detached,  an  advantage  which  paint- 
ing in  distemper,  certainly  does  not  pos- 
sess. 

The  same  author  likewise  declares,  that 
he  has  made  numerous  experiments,  with 
this  same  paint,  and  always  obtained  such 
constant  and  satisfactory  results,  that  he 
doubts  not  when  it  is  known,  that  it  will 
be  generally  adopted.  He  mentions 
amongst  others,  the  use  he  has  made  of 
it,  at  Barcelona,  both  in  the  interiour  and 
exteriour  of  houses,  and  he  has  invaria- 
bly remarkedjthatit  not  only  remained  un- 
altered by  the  sun,  the  air,  humidity,  and 
dryness,  but  that  it  was  also  exempt  from 
any  disagreeable  smell ;  so  that  places 
painted  with  it,  may  be  inhabited  on  the 
very  day  of  applying  it 

At  first  sight  one  would  be  led  to  ima- 
gine, that  the  new  kind  of  paint,  propos- 
VOL.  II. 


ed  by  M.  Carbonell,  is  almost  the  samb 
thing  as  the  milk-paint,  described  by  M. 
Cadet  de  Vaux.  The  latter  may  have  an- 
swered, but  when  we  reflect  on  the  mate- 
rial difference,  that  exists  between  the 
composition  of  the  serum  of  blood,  and 
that  of  milk,  we  shall  perceive  the  supe- 
riority of  M.  Carbonell's  paint  to  the 
other. 

For  the  rest,  experience  must  decide 
the  matter ;  and  it  is  to  be  presumed,  that, 
it  will  not  fail  to  show  which  of  the  two 
methods  deserves  to  be  adopted  in  pre- 
ference. 

PALLADIUM.  This  is  a  new  metal, 
first  found  by  Dr.  Wollaston,  associated 
with  platina,  among  die  grains  of  which 
he  supposes  its  ore  to  exist,  or  any  alloy 
of  it  with  iridium  and  osmium  (two  other 
new  metals)  scarcely  distinguished  from 
the  crude  platina,  though  it  is  harder  and 
heavier.  (See  Platina,)  and  also  an 
essay  by  Mr.  Cloud,  in  the  American  Phi- 
losophical Transactions.  Palladium  has 
not  been  introduced  into  any  of  the  arts. 

PALM  OIL.    See  Oil. 

PARTING.    See  Assaying. 

PASTE,denotes  a  preparation  of  wheat- 
en  or  other  flour,  boiled  up  and  incorpo- 
rated with  water,  till  it  acquire  a  viscid 
consistence.  It  is  used  in  various  trades, 
as  a  substitute  for  size,  or  glue,  in  past- 
ing or  cementing  papers,  books,  &c.  If' 
the  composition  be  intended  for  paper- 
hangings,  or  for  other  purposes,  where  a 
considerable  degree  of  adhesion  is  requir- 
ed, one  fourth,  fifth  or  sixth  part  in  weight, 
of  pulverised  resin  is  added ;  and,  if  the 
paste  is  to  be  still  more  tenacious,  gum- 
arabic,  or  any  kind  of  size,  may  be  dis- 
solved in  the  liquid,  while  the  mixture  is 
boiling.  As  this  viscous  compound,  un- 
less it  be  preserved  in  a  damp  place,  is 
apt  to  dry  speedily,  it  has  been  recom- 
mended, to  dissolve  a  little  sublimate  of 
mercury,  (in  the  proportion  of  one  drachm 
to  a  quart,)  in  the  water  employed:  thus, 
it  will  not  only  retain  its  fluidity,  but  will 
also  be  secured  from  the  depredations  of 
rats,  mice,  and  other  vermin. 

There  are,  however,  various  and  less 
expensive  vegetable  substances,  that  may 
be  aptly  substituted  for  the  valuable  arti> 
cle  of  flour ;  of  which  considerable  quan- 
tities are  annually  consumed  in  paste. 

PASTIL.    See  Dyeing. 

PATENTS  from  the  United  States,  how: 
obtained.  As  their  subjects  is  important, 
and  may  prove  of  utility  to  some  of  our 
readers",  we  shall  here  give  the  observa- 
tions of  Dr.  Thornton  on  the  subject,  tak- 
en from  the  National  Intelligencer. 

Having  the  honour  of  directing  or  su- 
perintending the  important  duties  of  i«r- 

k  k 


PAT 


PAT 


suing  patents  for  arts  and  inventions, 
which  formerly  were  thought  worthy  of 
the  labours  of  a  council,  composed  of  the 
secretary  of  state,  the  secretary  of  war, 
and  the  attorney  general  of  the  United 
States,  I  have  thought  it  a  duty  to  my  fel- 
low citizens,  to  publish  a  few  lines  of  in- 
formation to  facilitate  the  mode  of  acquir- 
ing patents,  by  which  many  will  be  ena- 
bled, to  dispense  with  long  journies  to  the 
seat  of  government,  or  with  troubling 
their  friends  by  a  tedious  correspondence. 

Before  an  application  be  made  for  a  pa- 
tent, I  would  advise  the  inventor  to  exa- 
mine well  the  Dictionaries  of  the  Arts  and 
Sciences,  the  Repertory  of  Arts,  and  other 
publications,  that  treat  of  the  mechanic 
arts,  to  endeavour  to  ascertain  if  the  in- 
vention be  new ;  also  to  make  inquiry  of 
scientific  characters,  whether  or  not  the 
invention  or  discovery  be  practicable. 
These  previous  inquiries,  will  sometimes 
prevent  great  trouble,  and  save  the  ex- 
pense of  much  time,  labour,  and  money  ; 
for  a  patent  does  not  confer  rights,  where 
just  claims  do  not  exist ;  and  as  there  is 
at  present  no  discretionary  power  to  re- 
fuse a  patent,  even  where  no  just  claim 
exists,  it  may  be  proper  to  caution  the  pur- 
chaser of  patent  rights,  against  the  sup- 
position, that  the  invention  patented,  is 
always  valuable,  or  new,  or  that  it  inter- 
feres with  no  previous  patent.  The  re- 
spectable names  of  the  president,  the  se- 
cretary of  state,  and  attorney  general  are 
requisite  to  give  validity  to  a  patent ;  but 
ought  never  to  be  considered  in  any  de- 
gree, as  evidence  of  the  originality  or  uti- 
lity of  invention.  The  issuing  of  patents 
is  grounded,  not  only  on  a  desire  to  pro- 
mote the  progress  of  useful  ails,  but  also 
to  prevent  the  loss  of  valuable  secrets ; 
for  many  have  been  buried  with  the  in- 
ventors, previous  to  the  organization  of 
this  system  of  protection  for  the  property 
of  talent,  mind,  and  genius.  Formerly  the 
arcana  of  any  profession,  were  withheld 
from  the  tyro  ;  his  initiation  was  gradual 
and  secret,  and  the  caution  with  which 
inventors  worked,  to  prevent  the  infringe- 
ment of  unprotected  rights,  confined  many 
important  inventions  to  limits,  too  narrow 
to  materially  benefit  either  the  inventors, 
or  the  world  :  at  present  the  law  grants 
a  monopoly  to  the  inventor,  for  a  limited 
time,  provided  the  art,  invention,  discove- 
ry or  machine,  be  duly  explained,  depo- 
sited, and  recorded,  for  the  benefit  of 
mankind,  as  soon  as  the  time  limited  has 
expired  ;  and  the  patent  is  not  only  an 
evidence,  that  the  inventor  has  formally 
confided  his  secret  to  the  public,  but  some 
declaration  of  the  protection  of  the  right, 
from  infringement :  nevertheless,  of  the 


right,  by  others,  a  jury  of  the  country  is 
only  competent  to  decide. 

The  geweral  law,  concerning  the  issuing 
of  patents  will  be  found  in  the  2d  vol.  of 
the  laws  of  the  United  States,  page  200, 
This  law  provides  for  citizens  only;  but 
a  subsequent  law,  vol.  5th,  page  88,  pro- 
vides  also  for  applicants,  who  have  resid- 
ed two  years  or  upwards,  in  the  United 
States,  and  who  are  not  citizens. 

In  applying  for  a  patent,  it  is  necessary 
to  attend  to  every  legal  form,  for  in  con- 
sequence of  inattention  to  forms  only,somc 
of  the  patents  issuing  formerly,  have  in 
the  course  of  law,  been  declared  null  and 
void. 

Mode  of  Application. 
Every  inventor  before  he  presents  his 
petition  to  the  secretary  of  state,  signify, 
ing  his  desire  of  obtaining  a  patent,  shall 
pay  into  the  treasury  of  the  United  States, 
thirty  dollars,  for  which  he  will  be  fur- 
nished with  duplicate  receipts ;  one  of 
which  he  shall  deliver  to  the  secretary  of 
state,  when  he  presents  bis  petition  :  and 
the  money  thus  paid,  ghall  be  in  full,  for 
the  sundry  services,  to  be  performed  in 
the  office  of  the  secretary  of  state,  conse- 
quent to  such  petition.  This  petition 
must  be  addressed  to  the  secretary  of 
state,  and  may  be  in  the  following  or  in 
a  similar  style. 

To  the  hen.  secretary  of  state  of 

the  United  States. 
The  petition  of  A.  B.—  of  — ~-  in  the 
county  of  and  state  of  respect- 
fully represents —  That  your  peti- 
tioner has  invented  a  new  and  useful  im- 
provement, "  [or  art,  machine,  manufac- 
ture or  composition  of  matter,  or  any  new 
and  useful  improvement  in  any  art,  ma- 
chine, manufacture,  or  composition  of 
matter]  in    not  known  or  used  be- 
fore his  application,"  the  advantages  of 
which  he  is  desirous  of  securing  to  him- 
self, and  his  legal  representatives :  he 
therefore  prays  that  letters  patent  of  the 
United  States,  may  be  issued,  granting 
unto  your  petitioner,  his  heirs,  admini- 
strators or  assigns,  the  full  and  exclusive 
right  of  making,  constructing,  using,  and 
vending  to  others  to  be  used,  his  said  im- 
provement, [art,  invention,  machine,  ma- 
nufacture, or  composition  of  matter,  &c.1 
agreeably  to  the  acts  of  congress,  in  such 
case  made  and  provided  ;  your  petitioner 
having  paid  thirty  dollars,  into  the  trea- 
sury of  the  United  States,  and  complied 
with  the  other  provisions  of  the  saic 
acts. 

A.  B 

[Date.] 


PAT 


PAT 


The  specification  or  description  of  the 
machine,  art,  discovery  or  invention,  must 
be  given  in  clear  and  specific  terms,  de- 
signating it  from  all  other  inventions,  and 
describing"  the  whole  in  such  a  manner, 
as  to  comprehend  not  only  the  form  and 
construction,  (if  a  machine)  but  also  the 
mode  of  using-  the  same  ;  and  if  it  be  only 
an  improvement  on  a  certain  machine  al- 
ready invented  by  the  applicant,  or  any 
other,  it  ought  to  be  so  mentioned  or  de- 
scribed :  and  as  this  specification,  descrip- 
tion, or  schedule  enters  into,  and  forms 
part  of  the  patent,  it  must  be  without  any 
references  to  a  model  or  drawing,  and 
must  be  signed  by  the  applicant  or  appli- 
cants, before  two  witnesses.  It  is  mate- 
rial that  this  be  in  good  language,  and 
correctly  written,  as  it  is  transcribed  into 
the  patent,  and  the  original  papers  will  be 
deposited  in  an  office  that  will  hand  them 
down  to  posterity,  by  which  the  honour 
of  the  country  is  concerned  in  this  atten- 
tion. The  modest  inventor  will  no  doubt 
exclude  those  panegyrics,  on  the  excel- 
lence of  his  invention  or  discovery,  which 
abound  sometimes  in  the  productions  of 
the  inferior  genius,  but  which  ought  not 
to  enter  into  the  patent. 

The  following  or  a  similar  oath  or  affir- 
mation taken,  (before  a  judge  of  any  of 
the  courts,  or  a  justice  of  the  peace,  or 
any  person  qualified  to  administer  an 
oath,)  by  the  applicant  or  applicants,  must 
be  subjoined  to  the  specification,  if  citi- 
zens of  the  United  States. 


Form. 


Countv  of 
State  of 


On  this    of          181    before  the 

subscriber,  a  justice  of  the  peace,  in  and 
for  the  county  aforesaid,  personally  ap- 
peared before  the  above  named  A.  B.  and 
made  solemn  oath,  (or  affirmation)  ac- 
cording to  law,  that  he  verily  believes 
himself,  to  be  the  true  and  original  inven- 
tor or  discoverer  of  the  art,  [machine,  in- 
vention or  improvement,  composition  of 
matter,  fcc]  above  specified  and  describ- 

ed,  for    (mention  here  the  object  or 

intention)    and  that  he  is  a  citizen 

of  the  United  States. 

J.  P. 

If  not  a  citizen  (or  citizens)  the  follow- 
ing addition  must  be  made  to  the  decla- 
ration, that  he  verily  believes  himself  to 
be  the  true  and  original  inventor  or  disco- 
verer of  the  art,  &c. 

And  that  the  same  hath  not,  to  the  best 
of  their  knowledge  or  belief,  been  known 
or  used  either  in  this  or  any  foreign  coun- 
try.—Also  that  he  (or  she)  hath 


resided  in  the  United  States  two  years  and 
upwards.  J.  p. 

The  specification  must  be  accompanied 
by  a  good  drawing,  in  perspective,  of  the 
whole  machine  or  apparatus — ^  where  the 
nature  of  the  case  admits  of  drawings  ; 
or  with  specimens  of  the  ingredients,  and 
of  the  composition  of  matter,  sufficient 
in  quantity,  for  the  purpose  of  experi- 
ment,  where  the  invention  is  of  a  compo- 
sition of  matter.'*  "  And  sucli  inventor 
shall,  moreover,  deliver  a  model  of  his 
machine,  provided  the  secretary  shall 
deem  such  model  to  be  necessary."  It  is 
requisite,  in  giving  a  drawing  of  the  ma- 
chine, to  give  also  rational  drawings  of 
the  interior,  when  the  machine  is  com- 
plex ;  and  every  drawing  should  be  ac- 
companied by  explanatory  references. 
When  a  machine  is  complex,  a  model  will 
likewise  be  necessary,  not  only  to  explain 
and  render  it  comprehensible  to  a  com- 
mon capacity,  but  also  to  prevent  in- 
fringements of  rights;  for  many  will 
plead  ignorance  of  drawings,  who  cannot 
avoid  the  conviction  of  wheels  and  pi- 
nions. 

The  drawings  ought  not  to  exceed  a 
quarto  size,  and  if  confined  to  octavo  they 
would  be  still  better,  where  it  can  be  done 
conveniently  and  distinctly. 

Many  of  the  drawings  in  this  office  are 
executed  in  a  very  handsome  style,  and 
do  much  credit  to  the  talents  of  the  gen- 
tlemen whose  names  are  ascertained.  If 
the  artists  would  always  sign  them,  in- 
formation might  be  given  to  the  appli- 
cants for  patents  where  to  apply  for  draw- 
ings. 

Among  the  best  I  have  received,  I  no- 
tice the  names  of  Messrs.  James  Akin, 
Philadelphia;  Jacob  Cist,  P.  M.  Wilkes- 
barre,  Pennsylvania;  Francis  Guy,  Balti- 
more; George  Hadfield ;  Nicholas  King, 
city  of  Washington ;  Nicholas  Peckman, 
Roxbury,  Massachusetts ;  John  R.  Penni- 
man,  Boston ;  Archibald  Robertson,  No, 
78,  Liberty-street,  New-York;  Archibald 
Steward,  Hartford,  Connecticut;  John 
Stickney,  Baltimore;  John  Stiles,  Wor- 
cester, Massachusetts;  William  Strick- 
land, Philadelphia;  James  Watson,  Utica, 
Oneida  county,  New-York. 

Many  being  without  the  names  of  ar- 
tists, I  cannot  do  all  the  justice  1  wish. 

The  papers  must  all  be  sent  under  co- 
ver to  the  secretary  of  state,  which  of 
course  renders  them  free  of  postage ;  but 
if  models  be  sent,  their  freight  or  car« 
riage  hither  must  be  paid ;  and  before 
packing  them,  the  name  or  names  of  the 
inventor  or  inventors  must  be  written 
thereon,  with  the  name  of  the  machine* 


PAT 


PAT 


and  the  date ;  for  sometimes  on  receiving 
them  it  is  difficult  to  know  to  whom  they 
appertain. 

The  Congress,  being"  impressed  with  a 
high  sense  of  the  value  of  the  inventions 
of  our  citizens,  have  purchased  an  ele- 
gant and  extensive  building,  wherein  pre- 
parations are  now  making  for  the  accom- 
modation of  a  very  numerous  collection 
of  machines  illustrative  of  the  ingenuity 
displayed ;  and  this  museum  of  the  arts, 
it  is  presumed,  will  stimulate  the  ingeni- 
ous to  send  the  models  of  their  machines 
and  inventions  in  a  style  that  will  rather 
honour  than  discredit  the  country. 

Copy-rights  of  books,  prints,  charts, 
maps.,  &c.  are  secured  by  depositing  be- 
fore publication,  a  printed  copy  of  the  ti- 
tle of  such  map,  chart,  book,  or  books,  in 
the  clerk's  office  of  the  district  court, 
where  the  author  or  proprietor  shall  re- 
side, who  will  record  the  same  ;  and  the 
author  or  proprietor  shall  within  two 
months  from  the  date  of  the  record,  cause 
a  copy  of  the  said  record  to  be  published 
in  one  or  more  of  the  newspapers  printed 
in  the  United  States,  for  the  space  ol  four 
weeks.  And  within  six  months  after  pub- 
lishing the  map,  chart,  book,  or  books, 
the  author  or  proprietor  shall  deliver  or 
cause  to  be  delivered  to  the  secretary  of 
state,  a  copy  ot  the  same ;  and  when  de- 
posited and  entered  into  the  patent  office, 
a  certificate  will  be  returned  of  its  being 
received-  This  will  secure  the  sole  right 
of  publication  for  fourteen  years  to  the 
author  or  proprietor,  if  a  citizen  of  the 
United  States,  or  resident — "  and  if,  at 
the  expiration  of  the  said  term,  the  author 
or  author:-.,  or  proprietors,  any  of  them  be 
living,  and  a  citizen  or  citizens  of  these 
United  Slates,  or  resident  therein,  the 
same  exclusive  right  shaii  be  continued 
to  him  or  them,  his  or  their  executors, 
administrators,  or  assigns,  for  the  further 
term  of  fourteen  years :  Provided  he  or 
they  shall  cause  the  title  thereof  to  be  a 
second  time  recorded,  and  published  in 
the  above  manner,  within  six  months  be 
fore  the  term  of  fourteen  years 


men,  and  the  zeal  for  the  promotion  of 
the  commercial,  the  agricultural,  and  the 
manufacturing  interest,  as  well  as  a  proof 
of  the  application  of  useful  science  to 
these  pur  poses. 

On  the  subject  of  patents,  Dr.  Mease 
very  properly  observes,  that  the  law  of 
the  United  States  respecting  patents  re- 
quires some  alterations,  which  it  may  be 
well  here  briefly  to  state- 

1.  Patents  should  be  granted  to  fo- 
reigners as  well  as  to  citizens. — The  pre- 
sent restriction  of  our  protection  to  the 
genius  of  the  latter,  is  not  only  illiberal, 
but  highly  detrimental  to  the  country,  by 
preventing  many  ingenious  men  from  di- 
vulging their  discoveries  as  soon  as  they 
come  among  us.  By  pursuing  an  oppo 
site  system,  England  has  become  the  de- 
pot of  the  inventions  and  discoveries  of  all 
Europe  and  America  :  and  hence  her  arts 
and  manufactures  have  arrived  at  a  de  • 
gree  of  perfection  of  which  no  other 
country  can  boast. 

2.  Inventors  and  discoverers  applying 
for  patents,  ought  to  be  obliged  to  secure 
to  the  country  the  advantage  of  their  dis- 
coveries, by  entering  into  an  obligation  to 
erect  or  make  for  sale  all  their  inventions, 
or  to  impart  a  knowledge  of  them  for  a 
reasonable  reward :  as  it  is  known  that 
many  persons  are  so  selfish,  as  neither  to 
make  use  of  them,  nor  to  grant  to  others 
that  liberty,  unless  at  an  extravagant 
price,  far  beyond  what  the  value  of  the 
invention  would  warrant. 

3.  Some  tribunal  should  be  established 
to  determine  upon  the  right  which  per- 
sons may  possess  to  obtain  a  patent.  It 
is  a  fact  wTell  known,  that  several  persons 
have  obtained  patents  irom  the  govern- 
ment  of  the  United  States,  for  supposed 
discoveries  and  inventions  which  have 
been  long  known,  or  in  use  in  Europe  ; 
some  of  these  are  noticed  in  the  Domestic 
Encyclopedia,  and  more  plagiaries  might 
doubtless  be  detected,  if  a  list  of  all  the 
patents  were  published,  which  have  been 
granted  in  the  United  States. 

4.  Provision  shouid  be  made  for  mak- 
ing void  the  claim  of  any  patentee,  as  in 
England,  if  not  supported  by  originality, 
or  if  he  wilfully  give  a  confused  and  er- 
roneous specification. 

The  editors  of  the  Retrospect  of  Phi- 
losophical, &c.  Discoveries,  in  relation  to 
British  patents,  vol.  5,  p.  554,  observes, 
that  the  perusal  of  this  specification  in- 
duces us  to  advert  to  the  opinion  enter- 
tained and  acted  upon  by  many  patentees, 
namely,  that  it  is  only  necessary  to  de- 
scribe the  principle  of  an  invention,  with- 
rights,  the  greater  part  of  which  have  ;  out  minutely  explaining  the  constructi  on 
been  adopted,  exhibits  the  industry  of  j  of  the  machine  founded  upon  it.   As  it  £ 


aforesaid. 


William  Thornton. 

The  number  of  patents  for  sundry  dis- 
coveries, improvements,  and  applications, 
are  daily  increasing,  which  shews,  that 
the  fertility  of  American  genius  is  always 
alive,  and  the  patriotism  of  the  people  al- 
ways ready  to  promote,  encourage,  and 
establish,  useful  improvements  for  the  be- 
nefit of  the  country. 

The  extensive  catalogue  of  patent 


PEA 


PEA 


the  plan  and  object  of  this  work  to  afford 
information  on  every  point  connected  with 
patents,  for  inventions,  we  deem  it  consis- 
tent with  *hat  view  to  introduce  a  few  re- 
marks, tending-  to  shew  the  fallacy  and 
danger  of  such  an  opinion. 

The  law,  permitting  to  the  crown  the 
privilege  of  granting  patents  of  monopo- 
ly for  new  inventions,  is  intended  for  the 
public  benefit ;  the  reward  it  offers  is  held 
out  as  an  incitement  to  call  genius  into 
exertion  for  the  advantage  of  the  commu- 
nity Every  patentee  ought  to  bear  in 
mind,  that  the  monopoly  granted  him  is 
the  price  paid  by  the  public  for  his  disco- 
very, and  the  patent  is  made  on  condition 
of  the  public  being  put  in  complete  pos- 
session of  it,  that  is  to  say,  the  specifica- 
tijon  required  by  the  letters  patent  must 
be  made  in  such  manner,  that  a  compe- 
tent workman  may  be  enabled  to  con- 
struct a  machine  capable  of  performing 
what  the  title  sets  forth,  without  any  in- 
vention of  his  own,  and  without  requiring 
any  further  instruction  than  what  the  spe- 
cification affords.  As  the  validity  of  the 
patent  depends  on  the  correctness  of  the 
specification,  it  behoves  the  patentee  to 
bestow  all  his  care  and  ability  on  this  ob- 
ject. 

To  draw  up  a  specification,  which  shall 
contain  a  luminous  and  minute  descrip- 
tion of  the  machine,  without  limiting  the 
patentee's  privilege  to  any  particular  mo- 
dification of  the  principles  on  which  it  is 
founded,  is  a  task  which  requires  not  on- 
ly talents  and  technical  knowledge,  but 
great  experience  in  the  nature  of  patent- 
light  ;  and  those  who  have  such  an  under- 
taking before  them,  will  do  well  to  avail 
themselves  of  any  assistance  they  can 
procure  to  contribute  to  its  being  ably 
done  ;  for,  provided  an  invention  be  origi- 
nal, the  patentee's  security  can  be  affect- 
ed by  nothing  but  an  injudicious  or  im- 
perfect specification. 

PEAT,  or  Turf,  as  it  is  called  by 
pome,  is  a  congeries  of  vegetable  matter, 
in  which  the  remains  of  organization  are 
more  or  less  visible,  consisting  of  trunks 
of  trees,  chiefly  oak,  fir,  birch,  alder,  ha- 
zle,  and  willow ;  of  leaves  and  fruits,  par- 
ticularly hazle  nuts ;  and  of  long  stringy 
fibres,  which  appear  to  be  for  the  most 
part  the  remains  of  the  sphagnum  palus- 
tre,  and  other  aquatic  mosses.  It  occurs 
for  the  most  part  in  extensive  beds  called 
peat  mosses,  either  occupying  the  surface 
of  the  soil,  or  covered  to  the  depth  of  a 
few  feet  with  sand,  gravel,  and  other  al- 
luvial matters.  It  is  met  with  abundantly 
in  the  northern  and  in  some  of  the  central 
districts  of  Europe,  in  all  moist  unculti- 
vated mountainous  tracts,  as  high  as  ve- 


getation extends;  it  is  also  frequent  in 
low  vallies  and  fenny  plains  ;  and  in  seve- 
ral parts  of  the  western  shore  of  Great 
Britain  runs  into  the  sea,  to  an  unknown 
extent,  as  in  the  harbour  of  Oban,  in  Ar- 
gyllshire ;  in  Lancashire,  a  little  to  the 
north  of  Liverpool ;  and  near  Towyn,  in 
Merionethshire.  It  is  found  also  in  some 
parts  of  the  United  States.  The  depth  of 
peat  mosses  is  very  various,  from  a  few 
feet  to  twelve  or  fifteen  yards,  or  even 
more.  The  consistence  of  peat  is  equal- 
ly various,  being  sometimes  in  a  semifluid 
state,  forming  a  black  impassable  wilder- 
ness, studded  here  and  there  by  tufts  of 
rushes :  when  more  solid,  it  is  scantily 
covered  over  with  heath  and  coarse 
grasses,  and  is  then  passable  by  sheep 
and  other  larger  animals,  especially  dur- 
ing the  dry  season  of  the  year.  In  all 
deep  peat  mosses,  it  is  found  that  the  up- 
per part  of  the  peat  is  looser,  of  a  lighter 
colour,  and  less  inflammable,  than  that 
which  forms  the  lower  part  of  the  bed. 
When  of  a  good  quality,  it  is  moderately 
compact,  and  may  readily  be  cut  into  so- 
lid masses,  like  bricks,  with  a  sharp  thin 
spade :  if  it  manifests  any  considerable 
degree  of  elasticity  and  resistance  to  the 
spade,  its  quality  is  always  found  to  be 
very  inferior.  By  exposure  to  the  air  it 
dries  slowly,  being  very  retentive  of  mois- 
ture, acquires  a  brownish-black  colour, 
becomes  moderately  hard,  and  in  this 
state  is  very  inflammable.  By  the  further 
action  of  the  weather,  it  by  degrees  falls 
to  pieces  and  is  decomposed,  though  very 
slowly.  When  kindled  in  an  open  gratej 
die  best  kind  burns  with  a  yellowish-blue 
flame  almost  like  charcoal,  and  a  less 
quantity  of  smoke  than  wood  affords  ;  it 
gives  out  a  great  quantity  of  heat,  and  is 
reduced  to  light  ashes  of  a  while  or  red- 
dish yellow  colour.  Some  varieties  of 
peat  are  considerably  changed  with  iron 
pyrites,  on  which  account  they  effloresce 
and  vitriolize  when  exposed  to  the  air, 
and  in  burning  give  out  a  strong  sulphu- 
reous odour,  much  smoke,  and  little  heat, 
and  afford  a  reddish  brown  ash.  Sulphats 
of  soda  and  magnesia  are  also  occasion- 
ally found  in  peat,  and  produce  a  similar 
bad  effect  on  it,  considered  as  a  combus- 
tible, as  pyrites  docs. 

Many  ingenious  attempts  have  been 
made,  especially  in  Fi  ance  and  Germanv, 
to  substitute  with  economy  the  charcoal 
of  peat  for  that  of  wood,  for  culinary  and 
metallurgical  purposes,  and  it  seems  to 
be  satisfactorily  proved,  that  a  given  bulk 
of  the  former  burns  somewhat  longer, 
and  affords  a  more  considerable  heat, 
than  of  the  latter;  but  that  it  is  incapable 
of  withstanding  the  action  of  a  forge  bel- 


PEA 


PEA 


lows,  and  is  apt  to  deteriorate  the  quality 
of  iron  that  is  smelted  with  it.  Another 
objection,  however,  occurs  to  the  employ- 
ment of  peat  charcoal,  on  the  score  of  its 
being  less  economical,  except  in  very  par- 
ticular circumstances,  than  wood  char- 
coal. It  cannot  be  prepared  in  the  man- 
ner of  common  charcoal,  on  account  of 
its  loose  texture,  without  a  prodigious  loss 
of  substance  and  deterioration  of  quality ; 
the  manufacturer  must  therefore  have  re- 
course to  distillation  in  iron  cylinders  or 
other  vessels;  but  to  effect  this,  so  large 
a  quantity  of  peat  must  be  consumed  as 
fuel,  that  the  value  of  the  charcoal,  the 
oil,  and  ammonia,  will  hardly  cover  the 
expense.  Hence  it  is  that  all  the  estab- 
lishments in  France  for  this  purpose, 
though  of  considerable  magnitude,  and 
carried  on  with  vigour  and  intelligence, 
have  been  entirely  abandoned. 

Peat  is  the  common  fuel  of  a  large  part 
of  Wales  and  Scotland,  and  of  many  dis- 
tricts in  England,  where  coal  is  not  readi- 
ly to  be  procured.  It  is  employed  not 
merely  for  domestic  purposes,  but  for 
burning  lime  and  bricks ;  and  its  ashes, 
though  destitute  of  alkali,  are  in  high  esti- 
mation as  a  manure,  being  applied  for  the 
most  part  in  the  form  of  a  top-dressing. 

PEAKL-ASH.    See  Potash. 

PEARLS. — Pearls  are  a  hard,  white, 
shining,  usually  roundish  body,  found  in  a 
testaceous  fish  resembling  an  oyster. 

The  fish  in  which  these  are  usually  pro- 
duced is  the  East  Indian  pearl-oyster,  as 
k  is  commonly  called.  Besides  this,  the 
common  oyster,  the  muscle,  and  several 
other  shell-fish,  produce  a  kind  of  pearl. 

All  pearls  are  formed  of  the  matter  of 
the  shell,  and  consist  of  a  number  of  coats, 
spread  with  perfect  regularity,  one  over 
another,  like  the  several  coats  of  an  onion. 
They  are  said  to  proceed  only  from  a  dis- 
temper in  the  fish,  analogous  to  the  be- 
zoars,  and  other  stony  concretions  in  se- 
veral animals  of  other  kinds. 

Though  these  ornaments  are  met  with 
in  all  parts  of  the  globe,  the  most  esteem- 
ed have  always  been  those  of  Asia,  and 
the  east  coast  of  Africa.  In  the  kingdom 
of  Madura,  which  lies  on  the  east  of  Ma- 
labar, there  are  many  pearl  fisheries.  Tu- 
tukurin,  or  Tutucorin,  is  the  principal,  if 
not  the  only  city,  on  the  fishery  coast.  At 
the  time  the  Portuguese  were  masters  in 
these  parts,  the  pearl  fishery  in  the  straits 
betwixt  the  island  of  Ceylon  and  the  con- 
tinent, was  stiled,  by  way  of  excellence, 
the  fishery,  and  very  deservedly ;  for, 
though  some  prefer  the  pearls  taken  near 
the  island  of  Baharen,  in  the  Persian  gulf, 
and  those  likewise  found  on  the  coast  of 
China  at  Hainan,  yet  the  produce  of  these 


fisheries  was  very  seldom  superior  to  that 
alluded  to.  At  present  the  pearl  fishery 
carried  on  in  the  strait  between  Ceylon 
and  the  continent  is  so  much  exhausted, 
that  it  takes  generally  five  or  six  years  be- 
fore a  sufficient  quantity  of  pearls  are  to 
be  found.  The  pearls  taken  at  Beharen, 
though  not  so  white  as  those  of  China 
and  Ceylon,  are  much  larger  than  those 
of  the  latter  place,  and  much  more  regu- 
larly shaped  than  the  former.  They  are 
of  a  yellowish  cast,  but  preserve  their 
golden  hue ;  whereas  the  whiter  kind  lose 
much  of  their  lustre  by  keeping,  particu- 
larly in  a  hot  climate.  The  shell  of  both 
these  species,  which  is  known  by  the  name 
of  Mother  of  Pearl,  is  used  for  various 
purposes.  There  are  a  variety  of  rivers 
in  the  Eastern  Tartary,  considerable  for 
pearl  fishery,  though  defective  in  shape 
and  colour  Many  rivulets  in  Livonia 
produce  pearls,  almost  equal  in  size  to 
the  oriental  ones.  In  Scotland,  especially 
to  the  northward,  about  Perth,  as  far  as 
Loch-Tay,  in  all  the  rivers  running  from 
lakes,  there  are  found  muscies  that  have 
pearls  of  more  than  ordinary  merit,  though 
seldom  of  large  size ;  but  this  fishery  is  at 
present  exhausted. 

The  American  pearl  fisheries  are  all  in 
the  gulf  of  Mexico,  along  the  coast  of 
Terra  Firma.  The  greatest  quantity,  and 
the  finest,  both  with  regard  to  weight  and 
water,  are  found  about  the  island  of  Mar- 
guerites. There  are  also  some  small 
pearls  in  the  South  sea,  particularly  in  the 
bay  of  Panama :  but  they  are  very  incon- 
siderable. The  West  Indians  knew  the 
value  of  their  pearls  before  the  discovery 
of  America,  and  when  the  Spaniards  ar- 
rived there,  they  found  great  quantities 
stored  up;  but  they  were  almost  all  im- 
perfect, and  their  water  yellow  and  smoky 
because  they  used  fire  in  opening  the  fish. 

There  are  two  seasons  for  pearl  fishing 
in  the  East  Indies ;  the  first  is  in  March 
and  April,  and  the  last  in  August  and 
September;  and  the  more  rain  there  falls 
in  the  year,  the  more  plentiful  are  these 
fisheries.  As  the  oysters  are  usually 
firmly  fastened  to  the  rocks,  the  divers 
commonly  take  iron  rakes  down  in  the 
sea  to  loosen  them ;  they  also  carry  down 
with  them  a  large  net,  in  the  manner  of  a 
sack,  tied  to  the  neck  by  a  long  cord,  the 
other  end  of  which  is  fastened  to  the  side 
of  the  bark.  This  net  is  to  hold  the  oys- 
ters gathered  from  the  rock,  and  the  cord 
is  to  pull  up  the  diver,  when  the  bag  is 
full,  or  when  he  wants  air.  He  sometimes 
precipitates  himself  sixty  feet  under  the 
water,  and  whatever  depth  he  be,  the 
light  is  so  great,  that  he  easily  sees  what- 
ever passes  in  the  sea.  To  his  great  con^ 


PEA 


PEA 


slcrnation  he  sometimes  perceives  mon- 
strous fishes,  from  which  a  1  his  address 
in  mudding  the  water,  &c.  will  not  always 
save  him,  and  this  is  one  of  the  greatest 
dangers  of  the  fishery.  The  best  divers 
will  keep  under  water  neaar  half  an  hour, 
and  the  rest  do  not  stay  less  than  a  quar- 
ter. During  this  time,  they  hold  their 
breath,  without  the  use  of  oils,  or  any 
other  liquors.  When  they  find  them- 
selves straitened,  they  pull  the  rope  to  be 
hove  up  in  the  air.  On  the  shore  they 
unload  their  barks,  and  lay  the  pearl  fish 
in  an  infinite  number  of  little  pits  dug  in 
the  sand,  raising  heaps  of  sand  over  them, 
and  in  this  condition  they  are  left  till  the 
rain,  wind  and  sun  have  obliged  them  to 
open,  which  soon  kills  them ;  upon  this 
the  flesh  rots  and  dries,  and  the  pearls 
thus  disengaged,  fall  into  the  pit  on  their 
taking  out  the  shells.  After  clearing  the 
pits,  and  cleaning  and  drying  the  pearls, 
they  are  passed  through  a  kind  of  sieve, 
according  to  their  sizes. 

Aleppo  is  the  staple  place  of  the  East 
Indian  pearls ;  from  thence  they  are  trans- 
ported to  Leghorn,  and  then  circulated 
through  Europe. 

PEARL  WHITE.— Put  some  good 
aquafortis  into  a  Florence  flask,  and  gra- 
dually add  to  it  bismuth,  broken  into 
small  pieces,  till  no  more  dissolves  ;  then 
let  the  solution  remain  till  it  is  transpa- 
rent. Add  to  this,  some  water,  and  a 
white  precipitate  will  be  formed,  which  is 
to  be  washed  and  dried.  This  is  white 
oxide  of  bismuth,  commonly  termed  ma- 
gistery  of  bismuth,  or  pearl  white. 

This  is  used  as  a  cosmetic,  and  is  sold 
by  the  perfumers;  but  it  very  much  im- 
pairs the  skin,  blacking  it  by  degrees,  so 
that  once  used,  it  m  .st  be  continued;  and 
it  is  also  to  be  feared,  that  it  has  besides 
deleterious  effects  upon  the  constitution. 
See  Colour-making. 

PF.ARLS,  Artificial.— -It  will  not  be  im- 
proper to  treat  in  this  place  of  artificial 
pearls,  as  it  is  a  branch  of  jewellery. 

The  ancients,  who  wrote  on  the  several 
sorts  of  precious  stones,  ranged  pearls 
among  the  jewels  of  the  first  class:  they 
have  at  all  times  been  in  high  esteem,  and 
have  been  employed  particularly  in  adorn- 
ing the  fair  sex. 

The  oriental  pearls  are  the  finest,  on  ac- 
count of  their  size,  colour,  and  beauty, 
being  of  a  silver  white  ;  whereas,  the  oc- 
cidental, or  western  pearls,  seldom  ex- 
ceed the  colour  of  milk.  The  best  pearls 
are  brought  from  the  Persian  gulf;  above 
the  isles  of  Ormus  and  Bassora,  called  also 
Balsora,  and  Basrah.  They  are  found  in 
Europe,  both  in  salt  and  fresh  waters  ; 
Scotland,  Silesia,  Bohemia,  and  Frisia, 


(that  part  of  Germany  lying  between  the 
Rhine  and  the  Ems,)  produce  very  fine 
ones ;  though  those  of  the  latter  country 
are  very  small. 

Art,  which  is  always  busy  to  mimic  na- 
ture, has  not  been  idle  to  bring  counter- 
feit pearls  to  the  greatest  perfection  :  they 
are  imitated  so  near,  that  the  naked  eye 
cannot  distinguish  them  from  pearls  of  the 
first  class,  or  the  real  ones. 

We  shall  here  present  the  curious  with 
several  receipts  how  to  counterfeit  pearls 
in  the  best  manner,  and  after  a  method 
both  easy  and  satisfactory,  so  as  to  render 
his  labour  pleasant,  and  make  it  answer 
his  expectations;  for  which  we  are  in- 
debted to  Imison. 

To  imitate  fine  Oriental  Pearls. 

Take  of  distilled  vinegar  two  pounds, 
Venice  turpentine  one  pound  ;  mix  them 
together  into  a  mass,  and  put  them  into  a 
cucurbit ;  fit  a  head  and  receiver  to  it, 
and,  after  you  have  luted  the  joints,  set 
it,  when  dry,  on  a  sand  furnace,  to  distil 
the  vinegar  from  it;  do  not  give  it  too 
much  heat,  lest  the  stuff  should  swell  up. 

After  this,  put  the  vinegar  into  another 
glass  cucurbit,  in  which  there  is  a  quan- 
tity of  seed  pearl,  wrapt  in  a  piece  of  thin 
silk,  but  so  as  not  to  touch  the  vinegar; 
put  a  cover  or  head  upon  the  cucurbit ; 
lute  it  well,  and  put  it  in  Bal.  Marias y 
where  you  may  let  it  remain  a  fortnight. 
The  heat  of  the  Balneum  will  raise  the 
fumes  of  the  vinegar,  and  they  will  soften 
the  pearls  in  the  silk,  and  bring  them  to 
the  consistence  of  a  paste ;  which  being 
done,  take  them  out,  and  mould  them  to 
what  bigness,  shape  and  form  you  please. 
Your  mould  should  be  of  fine  silver,  the 
inside  gilt;  you  must  refrain  from  touch- 
ing the  paste  with  your  fingers,  but  use 
silver-gilt  utensils,  with  which  fill  your 
moulds ;  when  you  have  moulded  them, 
bore  them  through  with  a  hog's  bristle, 
or  gold  wire,  and  let  them  dry  a  little  ; 
then  thread  them  again  on  a  gold  wire, 
and  put  them  in  a  glass;  close  it  up,  and 
set  them  in  the  sun  to  dry ;  after  they  are 
thoroughly  dry,  put  them  into  a  glass  ma- 
trass in  a  stream  of  running  water,  and 
leave  them  there  twenty  days;  by  that 
time  they  will  contract  the  natural  hard- 
ness and  solidity  of  pearls.  Then  take 
them  out  of  the  matrass,  and  hang  them 
in  mercury -water,  where  they  will  moist- 
en, swell,  and  assume  their  oriental  beau- 
ty ;  after  w  hich  shift  them  into  a  matrass, 
hermetically  closed  up,  to  prevent  any 
water  coming  to  them,  and  let  it  down 
into  a  well,  to  continue  there  about  eight 
days  ;  then  draw  the  matrass  up,  and  on 
opening  it  you  will  find  pearls  exactly  re* 


PEA 


PEA 


sembling  oriental  ones.  This  method  is 
very  excellent,  and  well  worth  the  trouble. 

It  may  be  necessary  to  state,  that  the 
Jialneum  Marice,  above  alluded  to,  is  a 
bath  of  sand,  heated  by  a  fire,  in  which 
chemical  apparatus  are  plunged,  to  sub- 
mit their  contents  to  a  digestive  heat.  It 
is  sometimes  called  Balneum  Maris. 

Mercury. water,  so  called  by  the  work- 
men, is  thus  prepared.  Take  plate-tin  of 
Cornwall,  calcine  it,  and  let  the  calx  be 
pure  and  fine :  then  with  one  ounce  of  the 
valx,  and  two  ounces  of  pure  mercury, 
make  an  amalgam;  wash  it  with  fair  wa- 
^er,  till  the  water  remains  insipid  and 
clear :  then  dry  the  amalgam  thorough- 
ly ;  put  it  into  a  matrass,  on  a  sand  bath, 
giving  it  such  a  heat  as  is  requisite  for 
sublimation.  When  the  matter  is  well 
sublimated,  take  off"  the  matrass,  and  let 
it  cool.  Take  out  that  sublimate ;  add 
one  ounce  of  Venice  sublimate  to  it,  and 
grind  it  together  on  a  marble ;  put  this 
into  another  matrass,  close  it  well,  and 
set  it  upside  down  in  a  pail  of  water;  and 
the  whole  mass  will  dissolve  in  a  little 
time ;  this  done,  filter  it  into  a  glass  re- 
ceiver ;  set  it  on  a  gentle  sand  heat  to 
coagulate,  and  it  will  turn  into  a  crystal- 
line substance :  this  beat  in  a  glass  mor- 
tar, with  a  glass  pestle,  to  a  fine  powder; 
sift  it  through  a  fine  sieve,  and  put  it  into 
a  matrass  ;  stop  it  close  up,  and  place  it 
in  balneum  mariae ;  there  let  it  remain  till 
it  resolves  again  into  water;  which  is  the 
mercury. water,  fit  for  the  above  mentioned 
use. 

Another  way  to  mahe  Artificial  Pearls. 
Take  oriental  seed-pearls ;  reduce  them 
into  a  fine  powder,  on  a  marble ;  then  dis- 
solve them  in  mercury-water,  or  clarified 
juice  of  lemons.  To  make  more  dispatch, 
set  them  in  a  cucurbit,  in  bal.  mar.  and 
you  will  see  presently  a  cream  arise  at 
the  top,  which  take  off  immediately :  take 
the  solution  off  the  fire,  and,  when  set- 
tled, pour  off  the  liquid  into  another 
glass,  and  save  it.  You  will  have  the 
pearl  paste  at  the  bottom,  with  which  fill 
your  silver-gilt  moulds  ;  then  put  them  by 
for  twenty -four  hours  :  bore  them  through 
with  a  bristle ;  close  up  the  moulds,  in 
barley  dough,  and  put  it  in  an  oven  to 
bake,  and  when  about  half  baked,  draw 
it  out,  take  out  your  pearls,  and  steep 
them  in  the  liquor  you  saved  before,  put- 
ting them  in  and  taking  them  out  several 
times ;  then  close  them  up  in  their  moulds, 
and  bake  them  again  with  the  like  dough  ; 
but  let  it  remain  in  the  oven  till  it  is  al- 
most burnt,  before  you  draw  it  out.  After 
you  have  taken  your  pearls  out  of  their 
moulds,  string  them  on  one  or  more  gold 


or  silver  threads,  and  steep  them  in  mer- 
cury water  for  about  a  fortnight:  after" 
which  time,  take  and  dry  them  in  the  sun^ 
in  a  well-closed  glass,  and  you  will  have 
very  fine  and  bright  pearls. 

Another  way. 

Dissolve  very  fine  pulverised  oriental 
pearls  in  alum-water ;  when  the  solution 
is  settled,  pour  off  the  water,  and  wash 
the  paste  first  in  distilled  water,  then  in 
bean  water,  and  afterwards  set  it  in  bal- 
neum marise,  or  horse-dung,  to  digest  for 
a  fortnight ;  this  done,  take  out  your  glass, 
and  the  matter  being  come  to  the  consist- 
ence  of  a  paste,  mould  il  as  you  have  been 
directed  before;  bore  and  string  the  pearls 
on  a  silver  thread,  and  hang  them  in  a 
well-closed  glass  alembic,  to  prevent  the 
air  coming  to  them  ;  thus  dried,  wrap 
every  one  up  in  leaves  of  silver ;  then 
split  a  barbel,  and  close  them  up  in  this: 
belly  thereof;  make  a  dough  of  bailey 
meal,  and  bake  the  fish,  as  you  do  bread ; 
then  draw  him,  take  out  your  pearls,  and 
dry  them  in  a  closed  glass  in  the  sun. 

To  give  them  a  transparency  and  splen- 
dour, dip  them  in  mercury -water  ;  or,  in- 
stead take  the  herb  gfflttdi,  [probably 
gratiola,  i.  e.  hedge-hyssop,  is  here  meant 
by  the  unknown  term  g  r  at  u/i]  and  squeeze; 
it  in  water ;  put  therein  six  ounces 
pearl,  one  ounce  of  nitre,  Gto12  Duntfe  of 
roach  alum,  one  ounce  of  litharge 
whole  being  dissolved,  heat  first  the  pearls 
and  then  dip  them  in  this  solution  to  cool ; 
repeat  this  about  six  times  successively. 

If  your  pearls  should  not  have  their  na- 
tural hardness,  then  take  two  ounces  of 
lapis  calaminaris,  in  impalpable  powder ; 
add  to  this  two  ounces  of  acid  of  vitriol, 
and  two  ounces  of  whites  of  eggs  beaten 
into  a  water ;  put  them  together  into  a 
retort ;  lute  a  receiver  to  it,  and  you  will 
distil  a  fair  water,  with  which,  and  some 
fine  barley  flour,  make  a  paste,  in  which 
put  your  pearls,  and  bake  them  as  be- 
fore ;  thus  they  will  become  exceedingly 
hard. 

Another  Method. 

Take  chalk  well  purified  and  cleansed 
from  all  grossness  and  sand,  i.  e.  whiten  ; 
of  this  make  a  paste,  and  form  pearls,  in 
a  mould  for  that  purpose;  pierce  them 
through  with  a  bristle,  and  let  them  dry 
in  the  sun  or  in  an  oven  ;  then  string  them 
on  a  silver  thread;  cover  them  lightly 
over  with  Armenian  bole,  diluted  in  the 
white  of  eggs;  and  when  cty,  drench 
them  with  a  pencil  and  fair  water;  lay 
them  over  with  leaf  silver,  and  put  them 
under  a  glass  in  the  sun  to  dry ;  when 
dry,  polish  them  with  a  dog's  tooth. 

To  give  them  the  true  colour,  make  a 


PEA 


fclue  of  vellum  shavings,  thcis :  after  you 
have  washed  them  in  warm  water,  boil 
them  in  fair  water,  in  a  new  earthen  pot 
or  pipkin,  to  some  thickness,  and  then 
strain  them  through  a  cloth.  When  you 
would  use  it,  warm  it  first,  and  dip  your 
string  of  pearls  into  it,  but  let  there  be  an 
interval  between  each  pearl,  so  as  not  to 
touch  one  another;  this  will  give  your 
pearls  a  natural  lustre. 

To  make  of  small  Pearls  a  fine  Necklace 
of  large  ones. 

Take  small  oriental  pearls,  as  many  as 
you  will ;  put  them  into  mercurial  water 
fifteen  days  and  nights  together,  and  they 
will  turn  soft,  like  a  paste ;  then  have  a 
pearl  mould,  made  of  silver;  into  this 
convey  the  paste  by  a  silver  spatula,  or 
such  "like  implement;  but  you  must  not 
touch  the  paste  with  your  fingers,  and  be 
very  careful  to  have  every  thing  nice  and 
clean  about  this  work :  when  it  is  in  the 
mould,  let  it  dry ;  bore  a  hole  with  a  sil- 
ver wire  through  it,  und  let  it  stick  there, 
till  you  have  more,  but  take  care  they  do 
not  touch  one  another  ;  then  have  a  glass 
-wherein  you  may  fix,  as  upon  a  pair  of 
stands,  your  wires  with  the  pearls :  put 
them,  well  closed  up,  in  the  sun  to  hard- 
en, and  when  you  find  them  hard  enough, 
put  them  into  a  matrass ;  lute  the  neck 
very  close,  and  sink  it  in  a  running  spring 
of  water  for  twenty  days,  in  which  time 
they  will  contract  their  natural  colour. 

It  is  asserted,  by  those  who  have  wea- 
ried themselves  with  the  hopes  of  form- 
ing small  imperfect  pearls  into  larger 
ones,  that  artificial  pearls  cannot  be  made 
of  the  materials  of  original  pearls.  The 
foregoing  receipts  are  laborious  and  ex- 
pensive ;  and  that  the  reader  may  have 
some  reward  for  his  exertions,  should  the 
experiments  balk  his  expectations,  we 
shall  add  here  a  tried  and  approved  me- 
thod of  imitating  pearls  from  other  mate- 
rials, which,  when  well  executed,  can  only 
be  distinguished  from  the  real  by  their 
absolutely  containing  fewer  blemishes  — 
The  method  was  kept  a  profound  secret 
for  many  years. 

Best  Method  of  imitating  Pearls. 

Take  the  blay  or  bleak-fish,  which  is 
very  common  in  some  of  our  rivers,  and 
scrape  oflj  in  a  delicate  way,  the  fine 
silvery  scales  from  the  belly.  *  Wash  and 
rub  these  in  fair  water,  changing  the  wa- 
ter, and  permitting  the  several  liquors  to 
settle:  the  water  being  carefully  poured 
off,  the  pearly  matter  will  be  found  at  the 
VOL.  IT. 


bottom,  of  an  oily  consistence,  called  by 
the  French  essence  d'orient.  A  little  of 
this  essence  is  dropped  into  a  little  hollow 
glass  bead  of  a  bluish  tinge,  and  shaken 
about,  so  as  to  fill  up  all  the  cavities  and 
surface  of  the  internal  part.  When  the 
essence  is  thoroughly  dry,  melted  w  hite 
wax  is  dropped  into  the  beads,  to  give 
them  weight,  solidity,  and  security. 

To  clean  Pearls  vihen  of  a  foul  colour. 

Take  pigeon's  dung,  moisten  it  with  alum- 
water  to  the  consistence  of  a  paste ;  put 
this  into  a  glass,  big  enough  to  hold  four 
times  the  quantity ;  put  into  this  your 
yellow-coloured  or  foul  pearls,  so  that 
they  may  be  covered  all  over,  and  set 
them  in  a  warm  place,  or  behind  an  oven; 
let  them  stand  for  a  month ;  then  take 
them  out,  and  fling  them  into  fresh  cold 
alum  water,  and  dry  them  carefully,  and 
your  pearls  will  become  fine  and  white ; 
if  you  repeat  the  operation  once  or  twice, 
they  will  be  done  to  greater  perfection. 

To  blanch  and  cleanse  Pearls. 

First  soak  and  cleanse  them  in  bran 
water ;  then  in  milk-warm  water,  and  last 
of  all,  steep  them  in  mercury  water ;  then 
string  and  hang  them  in  a  glass  ;  close  it 
well,  and  set  them  in  the  sun  to  dry. 

The  bran  water  is  made  thus  :  boil  two 
large  handfuls  of  wheaten  bran  in  a  quart 
of  water,  till  all  the  strength  of  the  bran 
is  drawn  out:  use  it  thus  ;  take  a  new- 
glazed  earthen  pan,  in  which  put  your 
pearls  on  a  string,  and  pour  the  third  pa.it 
of  the  bran  water  upon  them  ;  when  they 
have  soaked,  and  the  water  is  juat  warm, 
rub  your  pearls  gently  with  your  hands, 
to  clean  them  the  better;  continue  this 
until  the  water  is  cold;  then  throw  oft" 
that,  and  pour  on  another  third  part  of  the 
bran  water  that  is  boiling  ;  proceed  with 
this  as  you  did  before,  and  when  cold 
throw  it  away,  and  pour  on  the  remainder 
of  the  water,  still  proceeding  as  before  ; 
after  this,  heat  fair  water,  and  pour  it  on 
your  pearls,  to  refresh  them,  and  to  wash 
away  the  remains  of  the  bran,  by  shifting 
them,  and  pouring  on  fresh  warm  water : 
this  do  thrice,  without  handling  your 
peai  Is  ;  then  lay  them  on  a  sheet  of  clean 
white  paper,  and  dry  them  in  the  shade : 
then  dip  them  into  mercury  water,  to 
bring  them  to  perfection. 

Oilier  Methods  used  in  blanching  Pearls. 

Pound  plaister  of  Paris  to  an  impalpa- 
ble powder  ;  rub  the  pearls  therewith  very 
t  1 


PEN 


PER 


gently :  this  will  not  only  cleanse  them, 
but,  if  you  let  them  remain  in  this  powder 
twenty-four  hours  afterwards,  they  will 
still  be  the  better  for  it.  White  coral  has 
the  same  effect,  used  in  the  like  man- 
ner. 

White  tartar,  calcined  and  divested  of 
all  its  moisture,  is  very  good  for  the  same 
purpose. 

Salt,  well  dried  and  ground,  is  as  effec- 
tual as  any  of  the  former  things,  for  clean- 
sing of  pearls,  by  rubbing  them  there- 
with ;  and  if  afterwards  you  lay  them  up 
in  some  ground  millet,  it  will  contribute 
to  their  natural  brightness. 

We  give  the  foregoing  in  the  language 
of  Imison  ;  and,  as  to  the  truth  of  the  re- 
cipes we  cannot  vouch. 

PEDOMETER     See  Mechanics. 

PENCILS,  Black-lead,  are  made  of  a 
mineral  substance  called  plumbago,  or 
black-lead  ;  a  carburet  of  iron,  saw- 
ed into  slips,  and  fitted  into  sticks  of 
cedar  They  are  of  various  qualities. 
The  best  are  fine,  without  any  grit,  not 
too  soft,  and  that  cut  easily  without  break- 
ing. An  inferior  kind  is  made,  by  mixing 
up  the  dust  of  black-lead  with  gum  or 
glue,  and  forming  a  composition,  which 
is  fitted  into  sticks  in  the  same  manner  as 
the  best :  these  are  always  gritty,  and  do 
not  answer  so  well  for  most  drawings,  yet, 
being  cheaper,  they  may  be  used  upon 
many  occasions  It  is  necessary  to  exa- 
mine pencils  before  any  quantity  is  bought, 
by  cutting  one.  of  them,  because  the  com- 
position-pencils, having  the  same  out- 
ward appearance,  are  often  sold  for  the 
best. 

Black  chalk  pencil 

Is  made  of  a  fossil  substance,resembling 
slaty  coal,  which  is  cut  into  slips  for  draw- 
ing. It  is  generally  used  in  an  instrument 
called  a pott-crayon,  which  is  made  either 
of  steel  or  brass.  It  is  much  employed  for 
drawing  figures,  and  is  the  best  substance 
for  this  purpose,  in  making  drawings  from 
plaister,  or  after  the  life.  It  is  more  grit- 
ty than  black  lead,  but  is  of  a  deeper 
black,  and  has  not  the  glossiness  of  the 
former.  It  is  of  two  kinds,  French  and 
Italian  ;  the  former  is  soft,  and  the  latter 
hard. 

Hair  pencils, 

Are  made  of  camel's  hair,  put  into  a 
goose  or  swan  quill.  To  choose  these, 
moisten  them  a  little,  and  if  they  come  to 
a  point  without  splitting,  they  are  good  ; 
If  they  do  not  ,  they  are  not  fit  for  drawing 


with.  The  brushes  used  by  the  Chinese, 
made  of  a  white  hair  fitted  up  in  reeds, 
are  very  excellent  for  drawing ;  being 
much  superior  for  landscapes  and  many 
other  purposes,  to  ours  made  of  camel's 
hair,  as  they  are  more  elastic.  They  are 
not  sold  here  in  common,  but  they  may 
sometimes  be  met  with. 

PENDULUM.  See  Mechanics  and 
Horology. 

PERNAMBUCCO  WOOD.  See  Dye- 
ing  and  Bkat.il  Wood. 

PERSIMMON-TREE,  Biospyros  Vir- 
giniana,  or  American  prune,  date,  or 
plumb. 

A  fine  transparent  gum,of  a  light-brown 
colour,  insipid  to  the  taste,  readily  soluble 
in  water,  exudes  from  the  body  of  the 
tree. 

According  to  Dr.  Woodhouse's  experi- 
ments on  this  tree,  detailed  in  his  Inaugu- 
ral Dissertation,  Philadelphia,  1792,  it  ap- 
pears, that  the  juice  of  the  unripe  fruit, 
inspissated  in  the  sun,  yields  a  large  quan- 
tity of  a  brown,  semi-transparent,  astrin- 
gent, gummy  substance,  of  which  com- 
mon spirit  dissolves  a  larger  quantity, 
than  spirit  of  wine,  or  the  vegetable  oils. 
The  unripe  fruit  divided,  well  dried  in  the 
sun  and  reduced  to  powder,  may  be  used 
as  a  valuable  astringent  remedy,  [in  the 
forms  either  of  powder,  piils,  or  spiritous 
tincture,]  in  all  cases  requiring  astrin- 
gents. 

Use  of  the  Persimmon  in  the  arts. 

Dr.  Woodhouse  says,  The  unripe  juice 
of  the  plumb,  is  preferable  to  oak  bark, 
for  tanning.  Allowing  every  tree  to  pro- 
duce four  bushels  of  fruit,  and  suppose 
300  trees  cultivated,  the  quantity  of  gum 
resin,  which  would  be  produced,  would 
be  1800  pounds,  computing  six  pounds  to 
a  tree.  The  quantity  of  juice,  would  be 
several  hundred  gallons,  which  might  be 
kept  in  barrels  till  wanted  for  use.  Coun- 
try tanners  should  attend  to  this  useful 
fact. 

As  a  Black  Dye. 

Dr.  Woodhouse,  dyed  silk  with  an  ink 
made  of  this  substance,  which  was  as 
black,  and  bore  washing  as  well,  as  that 
dyed  with  galls  or  log-wood. 

From  an  excellent  Memoir  upon  this 
tree,  by  the  late  Isaac  Bartram  of  Phila- 
delphia, inserted  in  the  first  volume  of 
the  American  Philosophical  Transactions, 
it  appears,  that  from  half  a  bushel  of  per- 
fectly ripe  fruit,  mashed,  and  mixed  with 
two  gallons  of  water,  and  fermented  with 


PEW 


PIC 


a  small  quantity  of  yeast,  he  produced 
hall"  a  gallon  of  proof  spirit,  of  an  agree- 
able flavour.  Beer  is  also  made  from  the 
fruit  in  Maryland,  by  boiling  it  in  water, 
straining  and  fermenting  it,  and  adding 
hops  to  prevent  the  fermentation  from 
going  too  far. 

Bread  is  also  made  from  the  fruit,  by 
mixing  them  as  potatoes  are  with  flour, 
in  the  case  of  potatoe  bread.  The  wood 
of  the  tree  which  grows  rapidly,  burns 
nearly  as  well  as  our  favourite  hickory, 
and  its  ashes  yield  a  large  proportion  of 
salts.  The  great  value  of  this  tree  ought 
to  induce  farmers  to  cultivate  it. 

PETRIFACTIONS,  Artificial.  Put 
into  a  quantity  of  pounded  fluor  spar,  a 
few  bits  of  broken  glass,  and  pour  upon 
them  some  sulphuric  acid ;  fluoric  acid 
gas  will  be  disengaged,  holding  silex  in 
solution.  The  substances  to  be  made  to 
resemble  petrifications,  as  lizards,  frogs, 
branches  of  trees,  birds  nests,  &c.  must 
now  be  moistened  with  water,  and  placed 
in  a  vessel  connected  with  the  neck  of 
the  retort.  The  fluoric  acid  gas,  will  be 
absorbed  by  the  moisture,  adhering  to 
the  substances,  and  the  silex  will  be  pre- 
cipitated  upon  them,  like  a  sort  of  hoar 
frost,  which  will  have  a  very  beautiful  ap- 
pearance, and  is  very  durable. 

PETROLEUM.    See  Bitumen. 

PETUNTSE.  See  Porcelain  and 
Kaolin. 

I  EWTER,  which  is  commonly  called 
etain  in  France,  and  generally  confounded 
there  with  true  tin,  is  a  compound  metal, 
the  basis  of  which  is  tin.  Tne  best  sort 
consists  of  tin,  alloyed  with  about  a  twen- 
tieth, or  less,  of  copper  or  other  metallic 
bodies,  as  the  experience  of  the  workmen 
has  shown,  to  be  more  conducive  to  the 
improvement  of"  its  hardness  and  colour; 
such  as  lead,  zinc,  bismuth  and  antimony. 
There  are  three  sorts  of  pewter,  distin- 
guished by  the  names  of  plate,  trifle,  and 
ley-newter.  The  first  was  formerly  much 
used  for  plates  and  dishes;  of  the  second 
are  made  the  pints,  quarts,  and  other  mea- 
sures of  beer ;  and  of  the  ley-pewter 
wine  measures  and  large  vessels. 

The  best  sort  of  pewter  consists  of  17 
parts  of  antimony,  to  100  parts  of  tin  ;  but 
the  French  add  a  little  copper  to  this  kind 
of  pewter.  A  very  fine  silver-looking  me- 
tal is  composed  of  100  pounds  of  tin, 
eight  of  antimony,  one  of  bismuth,  and 
four  of  copper.  On  the  contrary,  the  ley- 
pewter,  by  comparing  its  specific  gravity, 
with  those  of  the  mixtures  of  tin  and  leai, 
must  contain  more  than  a  fifth  part  of  its 
weight  of  lead.  This  quantity  of  lead  is 
far  too  much,  considering  some  of  the  uses 


this  sort  of  pewter  is  applied  to ;  for  acid 
wines  will  readily  corrode  the  lead  of  the 
flagons,  in  which  they  are  measured,  into 
acetat  of  lead  ;  which  being  taken  inter- 
nally, is  productive  of  various  chronic  (lis 
eases,  as  the  colica  pictonum,  palsies,  stu- 
pors in  the  limbs,  &.C. 

It  is  asserted  that  English  tin  is  always 
a  mixed  metal,  when  exported  abroad  -. 
and  the  French  encyclopedists  in  particu- 
lar, (Article  Etain)  inform  us,  on  the 
authority  of  M.  Rouelle,  that  the  English 
tin,  when  cast  into  moulds  of  six  inches 
in  thickness,  and  cooled,  if  it  be  divided 
into  three  layers,  the  uppermost  has  three 
pounds  of  copper  in  the  100  of  tin :  the 
second  layer  has  five  pounds  of  lead,  in 
the  same  quantity  of  tin  ;  and  the  lowest 
layer  has  nine  of  lead  in  the  100  of  tin. 
GeofTroy  had  formerly  given  a  similar  ac- 
count of  the  English  tin,  with  some  varie- 
ty in  the  doses.  But  there  never  was  any 
other  foundation  for  such  an  assertion, 
than  that  pewter  has  been  mistaken  for 
tin  abroad  :  and  in  fact,  all  pewter  dishes, 
and  all  other  pewter  pieces,  are  called  by 
the  name  of  tin  ware,  all  over  Europe,  ex- 
cept in  England.  Nor  could  there  ever 
be  any  advantageous  motive  to  hinder  the 
export  of  pure  tin  from  England,  where 
it  is  found  in  greater  abundance  than  any 
where  else.  Beside  the  above,  neither 
Borlase,  nor  Pryce,  who  wrote  so  minute- 
ly on  the  method,  of  preparing  tin  in  Corn- 
wall, mention  any  operation  or  mixtures 
this  metal  undergoes  or  receives,  before 
or  after  it  is  cast  in  the  slabs,  blocks,  or 
pieces  of  tin,  in  which  size  and  form  it  is 
sold,  and  sent  to  every  market  in  Europe; 
so  that  the  whole  must  be  a  mistake  in 
terms,  as  already  mentioned,  by  taking 
pewter  simply  for  tin.    See  Tin. 

PICTURES. — 1  curious  method  of  form- 
ing them  by  nitrate  of  silver. — It  is  well 
known  that  light  has  a  powerful  effect  up- 
on any  of  the  metallic  oxides,  causing 
them  to  turn  black. 

Mr.  J.  Wedgewood  has  availed  himself 
of  this  property  for  copying  paintings  on 
glass,  and  making  profiles  of  figures  by 
means  of  nitrate  of  silver. 

Cover  white  paper,  or  leather,  with  a 
solution  of  nitrate  of  silver,  and  place  it 
behind  a  painting  on  glass,  which  is  ex- 
posed to  the  rays  of  the  run.  The  rays 
which  come  through,  will  blacken  the  pa- 
per ;  but  the  shades  will  be  more  or  less 
deep,  in  proportion  to  the  quantities  of 
light  transmitted  through  the  different 
parts  of  the  glass.  Where  the  glass  is 
transparent,  and  all  the  light  comes 
through,  the  paper  will  be  made  quite 
black ;  where  the  glass  is  quite  opaque, 


PIC 

and  does  not  transmit  any  light,  the  pa- 
per will  be  quite  white ;  and  there  will  be 
degrees  of  intensity  of  the  shadow  of  eve- 
ry variety  between  these. 

This  picture  is  not  sensibly  affected  by 
the  light  of  candles  or  lamps ;  but  the 
day-light  destroys  it  very  soon,  causing 
all  the  paper  to  become  black ;  nor  have 
any  means  hitherto  tried  for  preventing 
this,  been  successful. 

Besides  the  application  of  this  property 
of  nitrate  of  silver  to  copying  the  light 
and  shadow  of  paintings  on  glass,  it  may 
be  applied  to  some  others.  By  means  of 
it,  delineations  may  be  made  of  all  such 
objecs  as  are  partly  opaque  and  partly 
transparent  The  fibres  of  leaves,  and  the 
wings  of  insects,  may  be  pretty  accurate- 
ly represented  by  it,  by  only  making  the 
solar  rays  pass  tJi rough  them,  upon  pre- 
pared leather  or  paper. 

Professor  Davy  has  found,  that  the 
images  of  small  objects  produced  by 
means  of  the  solar  microscope,  may  be 
copied  without  difficulty  on  prepared  pa- 
per. He  found  that  the  best  proportion 
was  one  part  of  nitrate  to  about  ten  of 
water.  This  is  sufficient  to  enable  the  pa- 
per to  become  tinged,  without  hurting  its 
texture. 

The  following  receipts  are  given  by 
Imison. 

To  render  old  Pictures  as  fine  as  new. 

.  Boil  in  a  pipkin,  for  the  space  of  a 
quarter  of  an  hour,  one  quarter  of  a  pound 
of  gray  or  bril-ash,  and  a  little  Genoa 
soap.  Let  it  cool,  so  as  to  be  only  luke- 
warm, and  wash  your  picture  with  it ; 
then  wipe  it  Pass  some  olive-oil  on  it, 
and  then  wipe  it  off  again.  This  will 
make  it  just  as  fine  as  new. 

Ji  wash  to  clean  Pictures. 

Make  a  lye  with  clear  water  and  wood 
ashes ;  in  this  dip  a  sponge,  and  rub  the 
picture  over,  and  it  will  cleanse  it  perfect- 
ly. The  same  may  be  done  with  cham- 
ber-lye only  ;  or  otherwise,  with  white 
wine,  and  it  will  have  the  same  effect. 

Mother  Way. 

Put  iron  filings  in  a  handkerchief,  and 
rub  the  picture  with  it.  Then  pass  a  coat 
of  gum-arabic  water  on  the  picture. 

The  above  applications,  however,  as 
well  as  those  of  soap-water,  spirits  of 
wine,  turpentine,  &c.  require  to  be  em- 
ployed with  great  care;  because  they 


PIC 

are  apt  to  corrode  the  oil  of  the  paint- 
ing, and  thus  expose  the  colours  to  mate- 
rial injury  from  the  slightest  friction. 
Alkaline  solutions,  or  spirituous  liquors, 
therefore,  should  be  used  only  for  parti- 
cular spots,  that  have  resisted  the  action 
of  simple  water,  the  oil  of  olives,  or  fresh 
butter.  If  these  substances  were  timely 
resorted  to,  they  would,  in  general,  re- 
store the  picture  to  its  pristine  beauty, 
without  affecting  the  delicacy  of  its 
shades. 

To  takeoff,  instantly,  a  Copy  from  a  Print., 
or  a  Picture. 

Make  a  water  of  soap  and  alum,  with 
which  wet  a  cloth  or  paper  ;  lay  it  either 
I  on  a  print  or  picture,  and  pass  it  once  un- 
der the  rolling  press ;  then  going  round 
the  other  side  to  take  it  up,  you  will  have 
a  very  fine  copy  of  whatever  you  shall 
have  laid  it  upon. 

Prints,  or  engravings,  may  be  effectual- 
ly cleaned  by  immersing  them  in  weak 
oxymuriatic  acid.    See  Bleaching. 

PICKLE — A.  kind  of  brine  or  liquor, 
which  is  generally  prepared  of  salt  and 
nitre,  with  the  occasional  addition  of 
spices,  or  aromatic  herbs,  for  the  preser- 
vation and  seasoning  of  flesh -meat.  Pic- 
ties  also  signify  vegetables  preserved  by 
the  use  of  vinegar  and  aromatics. 

Under  the  article  Bacon,  we  have  al- 
ready stated  the  general  requisites  to  a 
good  pickle  :  we  shall,  therefore,  only  add 
a  few  particular  directions  relative  to  this 
subject.  It  has  beerr  ascertained  by  ex- 
perience, that  the  best  proportion  of  salt 
and  nitre  to  that  of  beef,  is  the  following : 
Take  8  lbs.  of  common  salt,  previously 
dried  in  a  warm  room,  and  1-J  oz.  of  salt- 
petre, likewise  in  a  dry  and  pulverized 
state,  to  every  112  lbs.  of  meat :  let  the 
salts  be  properly  incorporated  before  they 
are  applied.  The  beef  should  be  perfect- 
ly fresh  and  cool ;  as  otherwise  it  cannot, 
be  preserved  for  a  considerable  time  ;  the 
cask  or  vessel  ought  to  be  clean,  dry,  ana 
provided  with  a  moveable  lid  or  cover,  so 
as  to  support  a  weight  on  its  top.  Much, 
however,  depends  on  the  exact  propor- 
tion of  the  saline  ingredients  in  the  pic- 
kle ;  and  the  accuracy  with  which  these 
compound  salts  are  distributed  between 
the  different  layers  of  the  meat ;  for  if  any 
cavities  remain  between  the  pieces,  so  that 
air  can  penetrate  and  circulate  through 
the  interstices,  it  will  be  impossible  to 
keep  such  meat  many  weeks  in  an  eatable 
state. 

A  similar  preparation  may  be  used  for 
pork,  7nuttoni  and  geese;  which  last,  how- 


/ 


PIP 


PIT 


eveer,  should  be  divided  at  least  into  two 
equal  parts.  Thus,  the  farmers  in  Ger- 
many pickle  the  different  kinds  of  meat 
above  mentioned,  together  with  their  beef, 
in  the  same  vessels ;  chiefly  with  a  view 
to  fill  up  the  vacant  places  at  the  sides, 
and  prevent  the  corruption  of  the  hitter. 

PICKLING,  of  vegetables,  is  one  of  the 
modern  refinements  of  luxury,  which,  in 
point  of  healthiness,  deserves  no  commen- 
dation. It  is  effected  by  employing  the 
strongest  vinegar,  together  with  the  most 
heating  spices.  This  compound  is  ren- 
dered still  more  efficacious  by  previously 
boiling  the  vinegar  with  cream  of  tartar, 
before  the  aromatics  are  added.  In  such 
state,  most  vegetable  roots,  plants,  fruits, 
seeds,  walnuts,  &c.  may  indeed  be  pre- 
served for  any  length  of  time,  in  order  to 
stimulate  the  palate  occasionally ;  and  as 
it  is  supposed  to  promote  the  digestion  of 
animal  food — It  deserves  farther  to  be  re- 
marked, that  all  pickles  should  be  kept  in 
earthen,  but  uv.glazed  vessels  ;  no  copper 
or  verdigrease  must  be  employed ;  the 
air  should  be  carefully  excluded  ;  and  the 
room  in  which  they  stand  ought  neither  to 
be  damp  nor  warm. 

It  has  been  the  practice,  in  order  to  give 
pickles  a  beautiful  green  colour,  to  throw 
into  the  vinegar  a  copper  cent ;  but  the 
custom  is  dangerous,  and  is  now  abandon- 
ed. The  vinegar  makers,  or  sellers,  have 
also,  on  several  occasions,  in  order  to  ren- 
der their  vinegar  preferable,  introduced 
into  it  oil  of  vitriol,  or  sulphuric  acid  ;  but 
this  may  be  readily  discovered,  on  adding 
to  it  a  clear  solution  of  sugar  of  lead, 
which,  if  it  be  present,  will  give  a  white 
precipitate. 

PIGMENTS.    See  Colour  Making. 

PINCHBECK.    See  Copper. 

PINS.  See  Manufacture  of  Pins 
and  Needles. 

PINT  OIL.    See  Oil. 

PIPES,  Tobacco. — Manufacture  of. 
See  Pottery. 

PIPE  CLAY.— Thfc  difference  between 
the  porcelain  clay  Hr  those  of  more  mo- 
derate purity,  called  pipe  clays,  of  which 
there  are  plenty  in  this  country  and  in  Eng- 
land,is  commonly,  that  the  former  remains 
white  when  burned  in  an  open  fire ;  but 
the  latter,  containing  a  portion  of  mineral 
oil,  becomes  of  a  blueish-gray  in  a  mode- 
rate heat,  by  the  coal  produced  by  this 
combustion.  A  stronger  heal,  however, 
will  perfectly  consume  this  coal,  and  re- 
store the  whiteness.  On  the  whole,  how- 
ever, it  appears  rather  as  if  this  distinc- 
tion between  the  clays  used  in  pottery 
were  grounded  on  the  nature  of  the  pro- 
duct they  affordj  than  on  any  very  evident 


property  ascertainable  before  they  are 
wrought  and  baked.    See  Clay. 

PIPES  OFCONDUIT.  See  Hydrau- 
lics. 

PISOLITE.    See  Limestone. 

PISASPHALTUM.  A  species  of  hitu- 
men,  which  in  cold  weather  is  solid,  but 
at  other  times  has  a  sort  of  scmifluidity. 
It  differs  from  petroleum  only  in  possess- 
ing a  greater  degree  of  consistency. 

'  I'll' COAL.    See  Coal. 

PITCH.  Tar,  boiled  down  to  dryness 
is  the  common  black  pitch  :  this  part  of 
the  process  is  commonly  performed  in  a 
still,  in  order  to  have  an  essential  oil* which 
arises  in  the  boiling,  and  which  is  called, 
from  the  name  of  the  tree,  which  tar  is 
principally  prepared  from,  oleum  pini,  and 
oleum  txdx.  This  oil  is  greatly  valued 
by  painters,  varnishers,  &c,  on  account 
of  its  drying  quality  :  it  soon  thickens  of 
itself,  almost  to  the  consistence  of  a  bal- 
sam. Along  with  the  oil,  there  comes 
over  a  watery  liquor,  which  the  workmen 
injudiciously  throw  away  ;  though  it  is  a 
good  acid,  capable  of  being  applied  to  sun- 
dry useful  purposes  Neumann  knew  a 
person  in  France,  who  saved  by  it  several 
thousand  dollars. 

Pitch  is  not  a  pure  and  perfect  resin  ;  it 
has  not  only  suffered  a  notable  change, 
from  the  heat  employed  in  its  preparation, 
but  likewise  participates  of  the  other  prin- 
ciples of  the  wood,  of  a  gummy  and  saline 
nature,  and  of  a  burnt  earth.  Hence  its 
disposition  to  separate,  and  precipitate, 
when  melted  with  oils,  fats,  and  resins, 
into  plasters  and  ointments  ;  and  hence 
it  is  gradually  corroded,  by  air  and  mois- 
ture, when  employed  as  a  cement  or  de- 
fence for  wood,  or  other  substances,  \v. 
ships,  carriages,  cisterns,  casks,  shingle 
coverings  lor  houses,  he.  Ship  builders 
endeavour  to  improve  their  tar  and  pitch, 
so  as  to  render  them  more  durable,  by  va- 
rious additions. 

The  soot  which  arises  in  the  burning  of 
pitch,  is  the  substance  commonly  sold 
under  the  name  of  lampblack  :  in  France, 
the  pitch  is  burnt  for  this  purpose,  in  a 
kind  of  furnace  made  of  tiles,  so  dis- 
posed,  as  to  prevent  the  escape  of  the 
smoke. 

Lewis  informs  us,  that  what  is  called 
lampblack,  (originally  the  soot  collected 
from  lamps)  is  obtained,  in  different  parts 
of  Germany,  Sweden,  Sec,  not  from  pure 
resin  or  pitch,  but  from  the  dregs  and 
pieces  of  bark  of  the  tree,  separated 
in  their  preparation.  For  making  com- 
mon resin,  the  impure  juice  collected 
from  incisions,  in  pines  and  fir-trees,  is 
boiled  down  with  aiiltlc  Water,  and  strain- 


PLA 


PLA 


ed  while  hot  through  a  sack  :  on  cooling, 
the  resin  congeals  upon  the  surface  of  the 
water,  and  is  then  packed  up  in  barrels  ; 
it  is  distinguished  according  to  its  colour, 
into  white,  yellow  and  brown.  The  dross 
left  on  straining,  is  burnt  for  lampblack, 
in  a  low  oven,  from  which  the  smoke  is 
conveyed  by  a  long  passage,  into  a  square 
chamber,  having  an  aperture  in  the  top, 
upon  which  a  large  sack  is  fastened  :  the 
soot  concretes  partly  in  the  sack,  which  is 
occasionally  removed,  and  partly  in  the 
chamber  and  passage,  from  which  it  is 
swept  out. 

PITCH,  JEW'S.    See  Bitumen. 

PLANE,  Inclined.  See  Mecha- 
nics. 

PLAISTER  of  PARIS,  in  agriculture. 
See  Agriculture. 

PLAISTEk  of  PARIS,  in  moulding. 
See  Moulding  and  Casting. 

PLAISTER,  or  Stucco,  for  outside 
walls,  method  of  preparing  a  cheap  and 
durable  one,  by  H.  B.  Way,  of  Bridgeport 
harbour. 

Three  parts  of  sand,  to  one  of  lime, 
both  finely  sifted,  and  mixed  with 
lime-water  ;  if  used  as  stucco,  the 
first  coat  to  be  laid  on  half  the  thick- 
ness of  a  crown -piece  :  let  it  remain  two 
days,  then  with  a  painter's  brush,  wash 
it  over  with  strong  lime-water,  and  lay  on 
the  second  coat,  of  the  same  thickness. 
A  coal  half-bushel  of  lime,  was  put  into 
a  hogshead  of  water,  to  make  the  lime- 
water  ;  to  two  coal  half-bushels  more  of 
lime,  slacked  and  sif  ed,  which  then  mea- 
sured three  half-bushels,  were  added  nine 
half-bushels  of  sand  sifted,  and  well 
mixed  with  lime-water;  the  next  day 
it  was  again  mixed  up,  that  it  might  be 
well  incorporated.  The  coal  half-bushel, 
contained  exactly  thirteen  gallons  of  wa- 
ter, wine  measure,  and  would  exactly  hold 
1  cwt.  1  qr.  7  lb.  nett  of  the  sand  used. 

Mr.  Way  says,  that  his  house  is  great- 
ly exposed  to  the  spray  of  the  sea,  and 
that  by  means  of  the  stucco,  prepared  ac- 
cording to  his  receipt,  it  is  perfectly  free 
from  damp,  and  that  the  plaster  remains 
(April  1811,)  compact  and  durable.  The 
work  was  done  in  March  1805. 

Dr.  Mease,  in  the  Archives  of  Useful 
Knowledge,  says  that,  it  is  commonly  be- 
lieved, that  plaster  made  with  sea-sand, 
unless  well  washed  with  water,  would  be 
always  damp,  but  Mr.  Way  found  from 
what  had  been  done  in  his  dining  parlour 
and  passage,  that  it  was  always  dry,  al- 
though the  whole  of  the  sand  with  which 
it  was  done,  had  been  thrown  up  by  the 
sea,  and  must  have  been  always  at  spring 
tides,  covered  with  sea  water. 


The  following  facts  show  that  mortar* 

very  freely  impregnated  with  sea  salt,  i3 
even  improved  thereby. 

Mr.  Somerville  was  informed  by  the 
Earl  of  Wemyss,  "  that  in  completing  a 
line  of  enclosures  upon  his  estates,  on  the 
south  side  of  the  Frith  of  Forth,  he  was 
under  the  necessity  of  using  salt  water, 
not  only  for  slacking  the  lime,  but  for 
bringing  it  to  the  consistence  of  mortar, 
after  it  was  mixed  with  sand.  Contrary 
to  all  expectation,  the  work  done  with  the 
salt  water,  took  band  sooner,  than  w  hat 
was  done  with  fresh  water,  and  continues 
firm." 

The  Doctor  has  heard,  that  a  similar 
agreeable  disappointment,  was  experienc- 
ed by  a  gentleman  near  the  sea  coast,  in 
Jamaica,  from  the  use  of  salt  water  in 
making  mortar  The  extraordinary  soli- 
dity of  the  Tabby  or  Tapia  walls,  of  S. 
Carolina  and  Georgia,  made  of  shells, 
shell  lime  and  sand,  also,  may  arise  from 
the  salt  attached  to  the  shells  and  sand. 

PLATINA.  This  metal  has  hitherto 
been  found  only  in  one  state,  in  which  ac- 
cording to  most  mineralogists  and  che- 
mists, it  is  considered  as  native,  though 
Proust  is  inclined  to  consider  it,  as  in  the 
state  of  sulphuret.  From  this  latter  opi- 
nion, we  shall  take  the  liberty  to  dissent, 
and  shall  accordingly  describe  this  sub- 
stance, as, 

Native  Platina. 

The  colour  of  this  mineral  is  between 
silver  white,  and  steel  grey.  It  comes  to 
Europe  only,  in  the  form  of  flat,  and  more 
or  less  rounded  grains,  from  the  size  of 
a  pea,  which  is  rare,  to  that  of  fine  sand. 
The  surface  of  the  grains  is  moderately 
smooth,  and  they  possess  rather  a  low  de- 
gree of  metallic  lustre  :  by  friction  this 
brightness  approaches  to  that  of  polished 
iron  :  its  hardness  is  greater  than  that  of 
copper:  it  is  considerably  ductile,  and 
very  flexible  when  in  thin  plates.  Its  spe- 
cific gravity  is  variahjg,  but  is  seldom  lets 
than  16.5,  or  greatelBpin  17.2- 

It  is  infusible  before  the  blow-pipe,  and 
is  insoluble  in  acids,  except  the  oxymu- 
riatic  or  nitromuriatic  :  from  its  solution 
in  this  latter,  it  is  precipitable  by  muriat 
of  ammonia,  but  not  by  green  vitriol. 

Nothing  is  as  yet  known  of  the  geologi- 
cal situation  of  this  substance,  except  that 
it  accompanies  gold.  It  is  found  in  the 
Rio  del  Pinto,  and  near  Choco,  in  the 
Viceroyalty  of  Peru,  and  near  Carthagena, 
in  New  Granada. 

A  variety  of  the  above  in  smaller 
grains  and  of  a  darker  colour,  is  also  met 
with. 

Platina  was  first  brought  into  Europe 


PLA 


PLA 


in  1748,  by  Mr.  Charles  Wood,  assay-mas- 
ter of  Jamaica,  and  in  the  succeeding 
year,  specimens  were  presented  by  Dr 
13rownrigg,  to  the  Royal  Society.  These 
came  from  Carthagena,  from  which  place 
also  w  ere  dispersed  through  the  Spanish 
West  Indies,  various  toys  and  trinkets, 
consisting-  of  this  metal  alloyed  with  some 
other,  probably  silver,  as  the  price  of  the 
alloy  was  nearly  equal  to  that  of  this  lat- 
ter metal. 

Analysis  of  the  Ore. 

As  all  the  platina  winch  comes  to  us, 
has  previously  undergone  the  process  of 
amalgamation,  in  South  America,  it  gene- 
rally happens,  that  a  small  variable  quan- 
tity of  mercury  remains  in  it,  sometimes 
in  very  small  distinct  globules,  but  more 
generally  combined  with  gold  into  an 
amalgam.  The  easiest  way  of  separating 
the  mercury,  is  to  drive  it  oft'  by  hear, 
either  in  an  open  ladle,  or  in  an  earthen 
retort,  according  as  this  substance  is,  or 
is  not  to  be  retained  When  the  mercu- 
ry is  thus  got  rid  of,  the  remaining  pla- 
tina, has  generally  a  much  yellower  cast 
than  before,  on  account  of  the  particles 
of  gold  dispersed  through  it,  having  now 
acquired  their  characteristic  colour.  The 
ore  is  now  to  be  spread  thin  on  a  smooth 
table,  and  by  the  dextrous  application  of 
a  common  pair  of  bellows,  the  lighter 
particles  may  be  separated,  with  very  con- 
siderable accuracy  from  the  heavier  ones. 
The  former  consist  of  very  minute  crys- 
tals and  fragments  of  quartz,  and  of  two 
kinds  of  iron  ore  in  fragments,  and  in 
small  octoedrons :  of  which  some  are 
completely  attractable  by  the  magnet, 
(being  the  magnetic  iron  sand)  while  the 
others  are  not  the  least  so,  and  give  out 
when  roasted,  a  slight  sulphureous  odour 

The  heavier  particles  are  now  to  be 
treated  with  a  small  quantity  of  a  some- 
what diluted  nitromuriatic  acid,  by  which 
the  whole  of  the  gold  will  be  taken  up, 
with  some  iron  and  a  very  small  propor- 
tion of  platina,  and  the  other  ingredients. 
From  this  solution  the  gold  may  be  thrown 
dow  n,  by  means  of  green  sulphat  of  iron, 
and  purified  by  subsequent  fusion,  with 
a  mixture  of  nitre  and  borax.  The  pro- 
portion of  gold  contained  in  crude  platina, 
is  generally  pretty  considerable,  so  as  to 
render  it  well  worth  the  labour  of  the 
chemist,  to  separate  it,  if  he  is  possessed 
of  a  considerable  quantity.  From  one 
parcel,  consisting  of  100  ounces,  Proust 
obtained  7  ounces  of  gold,  and  from  ano- 
ther like  quantity,  he  procured  no  less 
than  13  ounces.  The  whitest  platina  is 
the  richest  in  gold,  the  black  varieties 
containing  little  or  none  of  it. 


After  the  separation  of  the  gold,  the 
platina  is  to  be  digested  into  nitromurin- 
tic  acid,  by  which  it  will  be  disolved,  with 
the  exception  of  a  black  matter,  which 
was  at  first  taken  for  plumbago,  but  which 
from  Mr  Tennant's  recent  analysis,  ap- 
pears to  be  a  compound,  of  two  new  me- 
tallic bodies,  that  have  obtained  the  names 
of  osmium  and  iridum.  By  the  addition 
of  muriat  of  ammonia,  to  the  nitromuriatic 
solution,  the  greatest  part  of  the  platina, 
is  thrown  down  in  the  form  of  a  yellow 
powder,  which  is  a  nearly  insoluble  am- 
moniaco-muriat  of  platina.  The  solution 
j  is  now  to  be  treated  with  zinc,  by  which 
all  its  metallic  contents,  except  the  iron, 
will  be  precipitated,  and  this  precipitate 
when  washed,  is  to  be  digested  in  very 
dilute  nitric  acid  :  by  this  menstruum  the 
copper  and  lead,  usually  contained  in 
crude  platina,  will  be  got  rid  of,  and  the 
remainder  is  to  be  dissolved  into  nitro- 
muriatic acid.  To  this  latter  solution, 
common  salt  is  to  be  added,  and  the  whole 
evaporated  to  dryness.  This  residual  salt 
contains  the  soda-muriats  of  platina,  pal- 
ladium, and  rhodium,  of  which  the  latter 
alone  is  insoluble  in  alcohol,  ai  d  may 
therefore  be  separated  from  the  former 
by  means  of  this  fluid.  The  alcoholic  so- 
lution now  contains  platina  and  palladi- 
um, from  which  nearly  the  whole  of  the 
former,  is  to  be  separated  by  sal  ammo- 
niac. The  solution  being  now  diluted,  the 
addition  of  prussiat  of  potash,  will  throw 
down  the  palladium,  in  the  form  of  a 
deep  orange  precipitate,  and  from  the  re- 
maining liquor  when  concentrated,  the 
platina  may  be  precipitated  by  muriat  of 
ammonia. 

Methods  of  -working  Platina. 
Tiie  great  infusibility  of  platina,  added 
to  the  strong  resistance  which  it  opposes 
to  common  menstrua, long  excited  the  at* 
lention  of  chemists,  and  artists,  and  has 
given  birth  to  various  ingenious  proces- 
ses, for  condensing  this  refractory  metal, 
into  malleable  masses,  and  forming  of  it 
crucibles  and  other  instruments  of  mate- 
rial service,  to  the  accuracy  and  simplici- 
of  chemical  analysis.  If  the  largest  and 
whitest  grains,  are  carefully  selected  from 
a  parcel  of  crude  platina,  it  will  be  found 
that  these  are  considerably  malleable 
even  when  cold,  and  still  more  so  when 
hot :  also  if  two  grains  are  laid  in  contact 
with  each  other,  and  then  brought  to  the 
highest  possible  white  heat,  they  may  be 
made  to  adhere  more  or  less  perfectly,  by 
a  stroke  with  the  hammer,  and  in  this 
way,  by  great  patience,  and  great  dexte- 
rity, it  may  be  practicable  to  form  a  few- 
grains  into  a  mass.   This  however,  is  by 


PLA 


PLA 


much  too  imperfect  and  tedious  a  method, 
to  be  employed  with  any  practical  advan- 
tage. 

It  was  early  discovered  that  arsenic 
combined  very  readily  with  platina,  form- 
ing an  alloy  of  easy  fusibility,  and  from  the 
volatility  of  the  former  of  these  metals, 
especially  when  in  contact  with  charcoal, 
it  was  expected  that  by  proper  manage- 
ment, nearly  the  whole  of  it  might  be 
driven  off,  leaving  the  platina  behind  in  a 
muss,  and  possessed  of  its  chtracteristic 
properties.  Willis,  Marggraaf,  Achard, 
■and  others  succeeded  to  a  certain  degree, 
and  fashioned  of  this  alloy,  crucibles  and 
other  chemical  utensils,  less  fusible  than 
silver,  and  capable  of  resisting  many  of 
the  common  menstrua.  M.  Jeanety  of 
Paris,  a  working  silversmith,  then  turned 
his  attention  to  the  same  object,  and  after 
long  practice  and  many  failures,  discover- 
ed by  far  the  best  method,  of  preparing 
and  working  this  alloy.  The  process  of 
this  artist,  as  reported  by  Berthollet  and 
Pelletier,  is  the  following  : 

Having  first  gronnd  the  crude  platina 
in  water,  and  Washed  it  over  in  order  to 
separate  the  earthy  matters,  with  which 
it  is  mixed;  take  "three  half  pounds  of 
the  metal,  three  pounds  of  white  arsenic, 
and  one  pound  of  pearl  ash:  mix  the  whole 
well  together,and  then  place  in  the  furnace 
of  any  convenient  construction,  a  crucible 
capable  of  holding  20  lbs.  of  the  above 
mixture.  As  soon  as  the  crucible  is  tho- 
roughly red  hot,  pour  in  one  third  of  the 
mixture,  and  keep  stirring  it  with  a  rod 
of  platina,  till  it  comes  into  a  state  of  fu- 
sion ;  then  add  another  third,  carefully 
stirring  it  as  before,  and  after  a  while  add 
the  remaining  third,  and  give  the  whole 
a  good  heat,  so  as  to  render  it  very  fluid. 
Then  withdraw  the  crucible,  and  after  it 
has  cooled,  gradually  break  it  up  :  there 
-will  be  found  a  weHformed  metallic  but- 
ton, covered  by  blackish  brown  scoria, 
which  acts  pretty  powerfully  on  the  mag- 
netic needle.  This  button  being  broken  j 
to  pieces,  (which  is  readily  done  on  ac-  j 
count  of  its  great  brittleness  )  is  to  be 
again  fused  with  white  arsenic,  and  pearl- 1 
ash  as  before,  and  the  metallic  mass  re-  j 
suiting  from  this  second  fusion,  is  gene-  \ 
rally  incapable  of  acting  on  the  magnetic 
neejtle  :  if  however,  this  should  not  be  the 
case,  a  third  fusion  with  arsenic  and  al- 
kali, must  be  had  recourse  to. 

The  first  step  of  the  process  being  thus 
finished,  a  Hat  bottomed  cylindrical  cruci- 
ble, about  oh  inches  in  diameter  is  to  be 
made  thoroughly  hot  in  a  furnace,  and  is 
then  to  be  charged  with  three  half  pounds 
©f  the  arsenicated  platina  mixed  with  an 
equal  weight  of  white  arsenic,  and  half  a 


pound  of  potash :  when  these  are  well 
mingled  and  entirely  fluid,  the  crucible  is 
to  be  removed  from  the  fire,  and  placed  to 
cool  in  a  horizontal  position,  in  order  that 
the  cake  of  metal  mav  be  of  an  uniform 
thickness.  The  crucible,  when  cold,  is 
to  be  carefully  b  oken,  and  having  re- 
moved the  scoriae,  there  will  be  obtained 
a  cake  of  metal  well  formed  and  sonorous, 
weighing  about  three  ounces  more  than 
the  arsenicated  platina  employed,  and 
now  quite  saturated  with  arsenic :  there 
is  no  danger  of  incorporating  too  much  of 
this  latter  ingredient,  it  being  constantly 
observed,  that  the  completeness  and  ra- 
pidity of  the  subsequent  purification  is  ex- 
actly in  proportion  to  the  quantity  of  ar- 
senic which  it  has  previously  been  made 
to  imbibe. 

The  metallic  mass  thus  procured  is  to 
be  placed  in  a  muffle,  and  the  heat  is  to 
be  gradually  increased  till  the  arsenic  be- 
gins to  evaporate ;  the  temperature  must 
then  be  kept  up,  as  nearly  as  possible  the 
same,  for  six  hours,  observing  especially 
not  to  increase  it,  lest  the  cake  melt.  At 
the  end  of  this  period,  the  cake  will  have 
become  considerably  porous,  and  is  now 
to  be  withdrawn  and  extinguished  in  com- 
mon oil ;  it  is  then  to  be  returned  to  the 
muffle,  by  which  a  further  quantity  of  ar- 
senic will  be  evaporated,  and  this  alter- 
nate application  of  oil  and  heating,  is  to 
be  continued  till  no  more  arsenic  makes 
its  appearance.  The  fusibility  of  the  mass 
diminishes  as  the  arsenic  is  got  rid  of,  so 
that  a  much  higher  temperature  may  be 
employed  in  the  latter,  than  in  the  former 
part  of  this  process.  Having  carefully 
burnt  off,  at  a  high  heat,  all  the  charcoal 
produced  by  the  decomposition  of  the  oil, 
the  spongy  cake  of  metal  is  to  be  digested 
in  nitrous  acid,  and  then  edulcorated  re- 
peatedly by  boiling  in  water.  Three  or 
more  of  the  cakes  are  then  to  be  put  into 
a  cylindrical  crucible,  and  heated  to  the 
highest  possible  degree  in  a  powerful  fur- 
nace :  while  they  are  thus  rendered  soft, 
and  iron  pestle  let  down  upon  them  will 
make  them  cohere :  they  are  then  to  be 
withdrawn  from  the  crucible,  heated  to 
the  utmost  in  a  smith's  fire,  and  carefully 
forged,  like  iron,  on  the  anvil  into  com- 
pact bars. 

The  advantage  of  this  process  of  M. 
Jeanety  is  its  cheapness,  not  requiring 
the  platina  to  be  previously  dissolved  in 
nitro-muriatic  acid;  but  on  the  other 
hand,  the  metal,  though  approaching  a 
state  of  purity,  is  by  no  means  absolutely 
pure:  it  contains  a  small  quantity  of  ar- 
senic and  iron,  together  with,  probably, 
the  whole  of  the  lead  and  copper  that 
may  have  been  casually  mingled  with  the 


PLA 


PLA 


ore,  as  well  as  the  palladium,  osmium, 
iridium  and  rhodium,  and  in  consequence 
of  this  mixture,  is  by  no  means  capable  of 
sustaining-  the  action  of  alkalies  and  a  high 
heat  with  so  little  injury  as  when  more  ac- 
curately purified. 

The  next  method  which  we  shall  men- 
tion of  purifying1  this  metal,  was  discover- 
ed by  count  Moussin  Pouschkin.  It  is  ef- 
fected in  the  following*  manner.  Dissolve 
the  crude  platina  in  nitro-muriatic  acid, 
and  throw  down  the  platina  by  muriat  of 
ammonia,  and  wash  the  precipitate  in  a 
little  cold  water.  Then  heat  the  yellow- 
powder  in  a  crucible  till  it  is  decomposed, 
and  the  platina  becomes  spongy,  and  re- 
turns to  the  metallic  state :  now  wash  the 
mass  with  hot  water,  and  boil  it  in  very 
dilute  muriatic  acid,  to  dissolve  out  any 
iron  that  may  be  casually  mixed  with  it; 
then  edulcorate  and  dry  the  residue.  Of 
this  residue  take  a  few  drachms,  with 
twice  its  weight  of  pure  mercury,  and  tri- 
turate the  mixture  in  a  stone  mortar  till 
an  amalgam  is  produced,  which  may  be 
effected  without  difficulty :  after  which, 
by  the  alternate  addition  of  mercury  and 
platina,  several  pounds  weight  of  ingre- 
dients may  be  amalgamated  in  the  course 
of  a  few  hours.  This  amalgam,  when  first 
made,  is  soft,  but  in  an  hour,  or  a  little 
more,  acquires  a  considerable  hardness  ; 
while  yet  soft  therefore,  it  should  be  close- 
ly rammed  into  a  tube  of  wood  of  conve- 
nient size,  and  after  it  has  become  hard, 
the  tube  with  its  contents  may  be  placed 
in  a  muffle,  and  by  the  time  that  the 
wooden  covering  is  consumed,  a  great 
part  of  the  mercury  will  be  volatilized,  so 
as  to  prevent  all  risk  of  the  bar  of  platina 
breaking,  when  deprived  of  the  support 
of  its  wooden  case.  The  metal  is  now  to 
be  cautiously  heated,  till  all  the  mercury 
is  driven  off;  after  which,  it  is  to  be 
forged  in  the  usual  way,  at  the  highest 
possible  heat. 

A  still  more  simple,  and  equally  effec- 
tual, manner  of  working  this  metal,  has 
been  published  by  Mr.  Knight.  The  pla- 
tina being  dissolved  in  nitro-muriatic  acid, 
and  precipitated  by  muriat  of  ammonia, 
the  yellow  powder  hence  resulting,  after 
being  edulcorated  by  washing  in  cold  wa- 
ter, is  to  be  thus  managed.  "  A  strong 
hollow  inverted  cone  of  crucible  earth 
being  procured,  with  a  corresponding 
stopper  to  fit  it,  made  of  the  same  mate- 
rials, the  point  of  the  latter  is  cut  off  about 
three-fourths  of  the  distance  from  the 
point  to  the  base.  The  platina,  in  the 
state  of  a  light  yellow  powder,  is  pressed 
tight  into  the  cone,  and  a  cover  being  fix- 
ed slightly  on,  it  is  placed  in  an  air  fur- 
nace, and  the  fire  raised  gradually  to  a 

VOL.  II. 


strong  white  heat.  In  the  mean  time  the 
conical  stopper,  fixed  in  a  pair  of  iron 
tongs  suitable  for  the  purpose,  is  brought 
to  a  red  or  a  bright  red  heat.  The  cover 
being  then  removed  from  the  cone,  the 
tongs  with  the  heated  stopper  is  intro- 
duced through  a  hole  in  the  cover  of  the 
furnace,  and  pressed  at  first  gently  on  the 
platina,  at  this  time  in  a  state  nearly  as 
soft  as  dough,  till  it  at  length  acquires  a 
more  solid  consistence.  It  is  then  re- 
peatedly struck  with  the  stopper,  as  for- 
cibly as  the  nature  of  the  materials  will 
admit,  till  it  appears  to  receive  no  further 
impression.  The  cone  is  then  removed 
from  the  furnace,  and,  being  struck  light- 
ly with  a  hammer,  the  platina  falls  out  in 
a  metallic  button,  from  which  state  it  may- 
be drawn,  by  repeatedly  heating  and  gen- 
tly hammering,  into  a  bar." 

The  last  method  that  we  shall  notice, 
and  one  that  has  been  attended  with  com- 
plete success,  was  invented  by  Mr.  T. 
Cock,  through  whose  liberality  we  are 
enabled  to  communicate  it  to  our  readers. 

The  platina  being  dissolved  in  nitro- 
muriatic  acid,  the  liquor  is  to  be  filtered 
through  clean  white  sand,  in  order  to  se- 
parate the  black  powder  which  Moats 
among  it.  The  clear  solution  being  then 
decomposed  by  sal  ammoniac,  the  yellow 
precipitate  is  to  be  collected,  moderately 
well  washed  in  warm  water,  and  dried. 
It  is  then  to  be  distributed  into  saucers, 
which  are  placed  in  a  small  oven  con- 
structed for  the  purpose,  where  they  are 
exposed  for  a  short  time  to  a  low  red  heat, 
in  order  to  bring  the  platina  to  the  metal- 
lic state,  and  to  drive  off,  by  sublimation, 
the  greater  part  of  the  muriated  ammo- 
nia. When  withdrawn,  it  is  a  spongy 
mass  of  a  gray  colour.  About  half  an 
ounce  of  the  platina  in  this  state,  is  to  be 
put  into  a  strong  iron  mould  about  2^ 
inches  long  by  1^  wide,  and  is  to  be  com- 
pressed as  forcibly  as  possible,  by  striking 
with  a  mallet  upon  a  wooden  pestle,  cut 
so  as  accurately  to  fit  the  mould  ;  another 
half  ounce  is  then  added,  and  treated  in 
the  same  manner ;  and  so  on  till  six  ounces 
have  been  forced  into  the  mould ;  a  loose 
iron  cover,  just  capable  of  sliding  down 
the  mould,  is  then  laid  upon  the  platina, 
and  by  means  of  a  screw  press,  almost 
every  particle  of  air  is  forced  out  from 
among  the  platina.  Tins  is  a  part  of  the 
process  that  requires  especial  care,  for  if 
any  material  quantity  of  air  is  left  in  the 
mass,  the  bar  into  which  it  is  formed  is 
very  apt,  in  the  subsequent  operations,  to 
scale,  and  be  full  of  flaws.  Tire  pressure 
being  duly  made,  the  mould  is  to  be  taken 
to  pieces,  and  the  platina  will  be  found  in 
the  form  of  a  dense  compact  parallqlo 

M  m 


PLA 

piped.  It  is  now  to  be  placed  in  a  char- 
coal forge  fire,  and  heated  to  the  most  in- 
tense white  heat,  in  order  completely  to 
drive  off  the  remaining  ammoniacal  mu- 
riat;  this  being-  done,  it  is  to  be  quickly 
placed  on  a  clear  bright  anvil,  and  gently 
hammered  in  every  direction  by  a  clean 
hammer.  This  is  to  be  repeated  several 
times,  at  the  end  of  which  the  mass  will  be 
perfectly  compact,  and  fit  to  be  laminated 
or  wrought  in  any  other  manner  that  the 
artist  chooses.  It  is  to  be  observed,  that 
while  the  platina  is  heating  it  must  lie 
loose  in  the  fire,  for  if  it  were  held  by  the 
tongs,  they  would  infallibly  become  weld- 
ed to  the  platina,  and  thus  greatly  damage 
it.  By  the  time  that  the  platina  is  thus 
drawn  down  to  a  compact  bar,  it  will  be 
covered  by  a  somewhat  reddish  semivi- 
treous  crust,  proceeding  chiefly  from  par- 
ticles of  the  ashes  melted  down  upon  it, 
and  extended  over  its  surface  by  the  ham- 
mer. To  remove  this,  the  bar  being  made 
red  hot,  is  to  be  sprinkled  over  with  pul- 
verized glass  of  borax,  and  then  kept  for 
a  few  minutes  at  a  white  heat ;  when  mo- 
derately cool,  it  is  to  be  plunged  into  di- 
lute muriatic  acid,  by  which  the  borax 
and  other  vitreous  matter  will  be  dissolv- 
ed, leaving  the  platina  with  a  perfectly 
clean  white  surface. 

Platina  has  been  worked  very  expedi- 
tiously in  this  city  by  Dr.  Bollman,  who 
had  crucibles,  spoons,  &c.  made  of  it. — 
for  particulars,  see  Cooper's  Emporium. 
We  do  not  deem  it  of  importance  to  dwell 
on  the  physical  and  chemical  properties 
of  this  metal,  which  belong  to  the  scien- 
tific chemist. 

Osmium,  Iridium,  Rhodium,  and  Palla- 
dium. 

Of  the  above  four  new  metals,  which 
have  recently  been  discovered  in  crude 
platina,  so  few  particulars  have  as  yet 
been  observed,  that  we  have  thought  it 
most  advisable  to  treat  of  them  in  an  ap- 
pendix to  the  article  platina. 

It  has  been  already  mentioned  that  in 
dissolving  crude  platina  m  nitro  muriatic 
acid,  a  black  powder  is  separated,  which 
lias  been  supposed  by  some  chemists  to 
be  oxyd  of  iron,  by  others  has  been  con- 
sidered as  plumbago,  but  has  been  lately 
discovered  by  Mr.  Tennant  to  contain  two 
new  metals.  If  in  treating  the  crude  pla- 
tina, a  large  proportion  of  strong  acid  at 
a  boiling  temperature  is  made  use  of,  near- 
ly the  whole  of  the  black  powder  is  dis- 
solved, and  the  platina  thrown  down  from 
the  solution  by  muriated  ammonia,  in- 
stead of  being  yellow,  of  a  brick  red. 
But  if  a  weaker  acid  at  a  much  lower  tem- 
perature is  employed,  the  solution  is  much 


PLA 

less  coloured,  and  nearly  3  per  cent,  of 
this  black  powder  remains,  which  may  be- 
readily  separated  by  filtration  and  wash- 
ing. 

This  black  matter  is  partly  in  scales, 
and  partly  pulverulent ;  it  leaves  black 
traces  on  paper  as  plumbago  does,  but 
differs  remarkably  from  this  latter  in  its 
specific  gravity,  which  is  =  10. ~. 

If  this  black  powder  be  mixed  with  a 
large  proportion  of  caustic  soda,  and  kept 
for  some  time  at  a  red  heat,  in  a  silver 
crucible,  the  mass  acquires  a  brownish- 
yellow  colour.  On  the  addition  of  water, 
a  peculiarly  pungent  odour  is  extricated, 
and  the  alkali,  with  part  of  the  yellow 
powder,  is  dissolved.  This  alkaline  solu- 
tion contains  the  oxyds  of  osmium  and 
iridium,  the  former  of  which  may  be  ob- 
tained pure,  by  slightly  supersaturating 
the  solution  with  sulphuric  acid,  and  pro- 
ceeding to  distillation ;  the  metallic  oxyd 
being  very  volatile,  rising  with  the  water, 
and  remaining  in  solution  with  this  fluid 
in  the  receiver :  as,  however,  a  little  sul- 
phuric acid  is  liable  also  to  come  over,  a 
second  very  gentle  distillation  is  required 
to  procure  the  oxyd  quite  pure.  The  so- 
lution thus  obtained  is  as  colourless  as 
water;  it  has  a  sweetish  taste,  and  a  strong 
peculiar  odour ;  it  does  not  change  vege- 
table blues  to  red.  Oxyd  of  osmium  may 
be  obtained  in  a  much  more  concentrated 
state,  by  distilling  the  original  black  pow- 
der with  nitre. 

We  have  already  mentioned  that  the 
black  powder  obtained  from  crude  plati- 
na, contains  both  osmium  and  iridium. 
The  method  of  separating  the  former  has 
been  just  now  treated  of;  we  shall  now, 
therefore,  proceed  to  show  how  to  pro- 
cure the  latter.  Yauquelin's  method  is, 
to  fuse  the  black  powder  with  four  times 
its  weight  of  caustic  potash,  which  gives 
a  green  saline  mass ;  by  digestion  with 
water  a  green  solution  is  obtained,  and 
some  green  powder  remains  undissolved. 
The  alkaline  solution  is  to  be  saturated 
with  muriatic  acid,  by  which  a  green  pre- 
cipitate will  be  obtained,  and  this,  toge- 
ther with  the  green  powder,  is  to  be  di- 
gested in  strong  muriatic  acid.  The  deep 
green  muriatic  solution,  thus  prepared, 
contains  the  oxyds  of  iridium,  iron,  and 
osmium,  and  when  heated  to  ebullition, 
its  colour  changes  to  a  bright  red.  It  is 
now  to  be  gently  evaporated  to  dryness, 
and  the  residue  being  treated  with  alco- 
hol, the  muriat  of  iron  will  be  dissolved, 
leaving  behind  a  red  powder  entirely  five 
from  this  metal.  This  red  powder  being 
calcined  at  a  red  heat,  in  an  open  cruci 
ble,  there  first  arises  muriatic  acid,  and 
then  a  vapour  which  tinges  the  flame  of 


PLA 


PNE 


the  coals  of  a  fine  blue,  and  which  doubt- 
less is  the  oxyd  of  osmium  ;  a  bhick  pow- 
der remains  behind,  which,  when  mixed 
Willi  borax,  and  exposed  to  a  very  high 
heat,  is  reduced  into  a  half  fused  granular 
melai,  of  a  white  colour,  and  very  brittle, 
which  is  pure  iridium. 

Alr.Tennanl  separated  the  iridium  from 
the  other  metals  with  which  it  is  mixed,  in 
the  following-  manner.  He  treated  the 
black  powder  alternately  with  caustic 
sofla,  and  muriatic  acid  ;  the  acid  solution, 
consisting- chiefly  of  muriat  of  iridium,  was 
of  a  dark-blue  colour,  which  afterwards 
became  of  a  dusky  olive-green,  and  final- 
ly, by  continuing  the  heat,  of  a  deep  red 
colour.  By  slow  evaporation  of  the  solu- 
tion, only  an  imperfectly  crystallized  saline 
mass  was  obtained,  but  this  being  dried 
on  blotting-  paper,  and  again  dissolved  in 
water,  afforded  on  evaporation  distinct  oc- 
toedral  crystals.  These  crystals  are  the 
pure  muriat  of  iridium,  and  when  dissolv- 
ed in  water  give  a  deep  orange-red  co- 
loured solution. 

All  that  is  hitherto  known  of  the  newly 
discovered  metal  called  Rhodium,  has 
been  communicated  to  the  public  by  Dr. 
Wollaston.  It  is  thus  procured.  Some 
crude  platina  being  digested  in  moderate- 
ly dilute  nitro-muriatic  acid,  a  brownish- 
red  solution  is  obtained :  from  this  the 
platina  is  to  be  separated  for  the  most  part 
by  muriat  of  ammonia,  and  the  residual 
liquor  is  to  be  heated  with  zinc;  by  this 
treatment  a  black  powder  will  be  obtain- 
ed, and  the  supernatant  fluid  will  consist 
of  the  muriats  of  zinc  and  iron.  This 
black  powder,  by  digestion  in  very  dilute 
nitric  acid,  will  be  freed  from  the  copper 
and  lead  which  it  usually  contains,  and 
the  residue  is  to  be  digested  in  dilute 
nitro  muriatic  acid,  till  every  thing  solu- 
ble is  taken  up.  To  this  solution  a  little 
common  salt  is  to  be  added,  and  the  whole 
evaporated  to  dryness ;  after  which,  by 
repeatedly  washing  with  warm  alcohol, 
the  soda  muriats  of  platina  and  palladium 
will  be  dissolved,  leaving  behind  a  pure 
soda  muriat  of  rhodium. 

An  alloy  of  six  parts  of  gold,  and  one 
of  rhodium,  differs  but  little  in  colour 
from  fine  gold,  but  is  much  more  diffi- 
cultly fusible.  The  specific  gravity  of 
rhodium  appears  to  be  somewhat  more 
than  11. 

In  the  preceding  account  of  rhodium, 
we  have  mentioned  the  method  of  sepa- 
rating the  soda-muriat  of  this  metal  from 
the  soda-muriats  of  platina  and  palladium, 
by  means  of  warm  alcohol.  This  being 
done,  the  alcoholic  solution  is  to  be  mix- 
ed with  a  solution  of  muriated  ammonia, 
by  which  the  greater  part  of  the  platina 


will  be  precipitated  :  the  supernatant  li- 
quor being  then  poured  oil'  and  diluted, 
there  is  to  be  added  prussiat  of  potash,  as 
long  as  any  precipitate  is  produced.  There 
is  thus  obtained  a  deep  orange  coloured 
sediment,  which  changes  by  degrees  to  a 
dirty  bottle  green.  1  his,  when  dried,  is 
to  be  heated  with  a  little  sulphur,  and  fus- 
ed into  a  button,  alter  which  it  is  to  be 
strongly  heated  with  glass  of  borax,  till 
on  cooling  it  acquires  a  bright  metallic 
surface;  being  now  separated  from  the 
borax  and  exposed  to  the  flame  of  the 
blowpipe,  the  sulphur  is  volatilized,  and 
there  remains  behind  a  spongy  malleable 
metallic  mass,  which  is  pure  Palladium. 

This  metal  in  its  colour  greatly  resem- 
bles platina;  when  rolled  into  a  thin  lami- 
na, it  is  very  flexible,  but  not  very  elastic. 
Its  specific  gravity  varies  from  10.9  to 
11.9. 

PLATING.— The  covering  of  the  sur- 
face of  topper  with  stiver  or  plating,  is 
performed  in  the  following  manner:  Up- 
on small  ingots  of  copper,  plates  of  silver 
are  bound  with  iron  wire,  generally  allow- 
ing one  ounce  of  sliver  to  twelve  ounces 
of  copper.  The  surface  of  the  plate  of 
silver  is  not  quite  so  large  as  that  of  the 
copper  ingot.  Upon  the  edges  of  the 
copper  which  are  not  covered  by  the  sil- 
ver, a  little  borax  is  put ;  and  by  expos- 
ing the  whole  to  a  strong  heat,  the  borax 
melts,  and  in  melting  contributes  to  fuse 
that  part  of  the  silver  to  which  it  is  conti- 
guous, and  to  attach  it  in  that  state  to  the 
copper.  The  ingot,  with  its  silver  plate, 
is  then  rolled  under  steel  rollers,  moved 
by  machinery,  till  it  is  of  a  certain  thick- 
ness ;  it  is  afterwards  cut  to  a  greater  or 
less  extremity,  according  to  the  use  for 
which  it  is  intended. 

An  ounce  of  silver  is  often  rolled  ou' 
into  a  surface  of  about  three  square  feet, 
and  its  thickness  is  about  the  three  thou- 
sandth part  of  an  inch  ;  and  hence  we 
need  not  wonder  at  the  silver  being  soon 
worn  off  from  the  sharp  edges  of  plated 
copper,  when  it  is  rolled  to  so  great  an  ex- 
tent. 

What  is  commonly  called  French  plate, 
is  not  to  be  confounded  with  plated  cop- 
per. French  plate  is  made  by  heating 
copper,  or  more  commonly  brass,  to  a  cer- 
tain degree ;  silver-leaf  is  then  applied 
upon  the  heated  metal,  to  which  it  ad- 
heres by  being  heated  with  a  proper  bur- 
nisher.   See  Silvering. 

PLUMB  AGE.    See  Coal. 

PLUMBING.  See  Manufacture  of 
Lead. 

PLUME.    See  Manufacture  of 
Military  Feathers,  &,c. 
PNEUMATIC  COOK,  is  a  simple,  in 


POI 


roi 


genious,  and  useful  contrivance  for  tap- 
ping air-tight  casks,  which  obviates  the 
necessity  of  a  vent  peg.  The  inventor, 
Mr.  Robert  Hare,  jun.  in  giving  a  descrip- 
tion of  this  invention,  observes,  "  it  is 
Well  known  that  an  air-tight  cask  is  usual- 
ly tapped  by  means  of  two  apertures,  one 
in  the  upper  part  for  the  admission  of 
air,  the  other  below  for  the  emission  of 
the  fluid;  or,  in  other  words,  by  means  of 
a  vent  peg  and  cock.  This  method  would 
not  be  very  objectionable,  were  the  vent 
peg  always  firmly  replaced  as  soon  as  the 
admission  of  air  "becomes  no  longer  neces- 
sary; but  this  is  seldom  attended  to,  and 
the  consequence  is  the  frequent  sourness 
or  vapidity  of  vinous  liquors.  The  quan- 
tity of  liquor  thus  annually  spoiled  by  this 
omission  of  vent  pegs,  must  be  immense ; 
and  must  be  particularly  great  in  those 
families  where  tapsters  are  too  numerous 
to  be  responsible  for  neglect. 

To  obviate  these  evils,  Mr.  Hare  has 
contrived  a  cock  with  two  perforations, 
which  are  opened  or  shut  by  turning  the 
same  key,  the  air  entering  at  the  upper 
perforation  the  fluid  passing  out  at  the 
lower,  with  a  velocity  proportioned  to  the 
depth  of  the  emitting  orifice  below  that 
which  admits  the  air  into  the  cask.  The 
fixed  air,  however,  which  is  generated  in 
casks  containing  vinous  liquors  will  some- 
times more  than  counteract  the  pressure 
of  the  atmosphere,  and  thus  dispose  the 
liquor  to  issue  through  every  aperture 
In  this  case,  while  the  cock  is  open,  it 
will  be  necessary  to  close  the  upper  ori- 
fice with  the  thumb,  while  the  fingers  are 
holding  the  key. 

The  cock  must  be  of  a  bended  firm,  so 
that  the  key  may  be  situated  be!  ow  the 
orifice  which  receives  the  liquor,  and  the 
nozle  should  taper  downwards  in  order 
to  give  a  sufficient  velocity  to  the  fluid 
from  the  cask. 

POISONS.— The  principal  part  of  the 
following  observations  we  have  taken  from 
Henry's  Chemistry. 

Jlfethod  of  detecting  Poisons. 
When  sudden  death  is  suspected  to 
have  been  occasioned  by  the  administra- 
tion of  poison,  either  wilfully  or  by  acci- 
dent, the  testimony  of  the  physician  is  oc- 
casionally required  to  confirm  or  invali- 
date this  suspicion.  He  may  also  be 
sometimes  called  upon  to  ascertain  the 
cause  of  the  noxious  effects  arising  from 
the  presence  of  poisonous  substances  in 
articles  of  diet ;  and  it  may  therefore 
serve  an  important  purpose,  to  point  out 
concisely  the  simplest  and  most  practica- 
ble modes  of  obtaining,  by  experiment, 
the  necessary  information. 


The  only  poisons,  however,  that  can  be 
clearly  and  decisively  detected  by  chemi- 
cal means,  are  those  of  the  mineral  king- 
dom. Arsenic,  and  corrosive  sublimate, 
[I  use  the  term  arsenic,  instead  of  the 
more  proper  one,  arsenous  acid ;  and  cor- 
rosive sublimate,  for  muriate  of  mercury ; 
because  the  former  terms  are  more  gene- 
rally understood,]  are  most  likely  to  be 
be  exhibited  with  the  view  of  producing 
death ;  and  lead  and  copper  may  be  in- 
troduced undesignedly,  in  several  ways, 
into  our  food  and  drink.  The  continued 
operation  of  the  two  last  may  often,  un- 
suspected, produce  effects  less  sudden 
and  violent,  but  not  less  baneful  to  health 
and  life,  than  the  more  active  poisons  ; 
and  their  operation  generally  involves,  in 
the  pernicious  consequences,  a  greater 
number  of  sufferers. 

Method  of'  discovering  Arsenic. 

When  the  cause  of  sudden  death  is  be- 
lieved, from  the  symptoms  preceding  it, 
to  be  the  administration  of  arsenic,  the 
contents  of  the  stomach  must  be  atten- 
tively examined.  To  effect  this,  let  a  li- 
gature be  made  at  each  orifice,  the  sto- 
mach removed  entirely  from  the  body,  and 
its  whole  contents  washed  out  into  an 
earthen  or  glass  vessel.  The  arsenic,  onv 
account  of  its  greater  specific  gravity,  will 
settle  to  the  bottom,  and  may  be  obtained 
separate  by  washing  off  the  other  sub- 
stances, by  repeated  affusions  of  cold  wa- 
ter. These  washings  should  not  be  thrown 
away  till  the  presence  of  arsenic  has  been 
clearly  ascertained.  It  may  be  expected 
at  the  bottom  of  the  vessel  in  the  form  of 
a  white  powder,  which  must  be  carefully 
collected,  dried  on  a  filter,  and  submitted 
to  experiment. 

(A.)  Boil  a  small  portion  of  the  powder 
with  a  few  ounces  of  distilled  water,  in  a 
clean  Florence  flask,  and  filter  the  solu- 
tion. 

(13.)  To  this  solution  add  a  portion  of 
water,  saturated  with  sulphuretted  hydro- 
gen gas.  If  arsenic  be  present,  a  golden- 
yellow  sediment  will  fall  down,  which  will 
appear  sooner,  if  a  few  drops  of  acetic 
acid  be  added. 

(C.)  A  similar  effect  is  produced  by  the 
addition  of  sulphuret  of  ammonia. 

(D.)  To  a  little  of  the  solution  (A.), 
add  a  single  drop  of  a  weak  solution  of 
carbonate  of  potash,  and  afterward  a  few 
drops  of  a  solution  of  sulphate  of  copper. 
The  presence  of  arsenic  will  be  manifest- 
ed by  a  yellowish-green  precipitate;  or 
boil  a  portion  of  the  suspected  powdev 
with  a  dilute  solution  of  pure  potash,  and 
with  this  precipitate -the  sulphate  of  cop 
per,  when  a  similar  appearance  will  en 


POI 

sue  still  more  remarkably,  if  arsenic  be 
present.  The  colour  of  this  precipitate 
is  perfectly  characteristic.  It  is  thut  of 
the  pigment  called  Scheele's  green.  To 
identify  the  arsenic  w  ith  still  greater  cer- 
tainty, it  may  be  proper,  at  the  time  of 
making  the  experiments  on  a  suspected 
substance,  to  perform  similar  ones,  as  a 
standard  of  comparison,  on  what  is  ac- 
tually known  to  be  arsenic.  Let  the  co- 
lour, therefore,  produced  by  adding  an 
alkaline  solution  of  the  substance  under 
examination,  to  a  solution  of  sulphate  of 
copper,  be  compared  with  that  obtained 
by  a  similar  admixture  of  a  solution  of 
copper  with  one  of  real  arsenic  in  alkali. 

(E.)  The  sediments,  produced  by  any 
of  the  foregoing  experiments,  may  be  col- 
lected, dried,  and  laid  on  red-hot  char- 
coal. A  smell  of  sulphur  will  first  arise, 
and  will  be  followed  by  that  of  garlic. 

(F.)  But  the  most  decisive  mode  of  de- 
termining the  presence  of  arsenic,  is  by 
reducing  it  to  a  metallic  state,  in  which 
its  characters  are  clear  and  unequivocal. 
For  this  purpose,  let  a  portion  of  the 
white  sediment,  collected  from  the  con- 
tents of  the  stomach,  be  mixed  with  three 
times  its  weight  of  black  filux;  or,  if  this 
cannot  be  procured,  with  two  parts  of  ve- 
ry dry  carbonate  of  potash  (the  salt  of 
tartar  of  the  shops,)  and  one  of  powder- 
ed charcoal.  Procure  a  tube  eight  or 
nine  inches  long,  and  one  sixth  of  an  inch 
in  diameter,  of  thin  glass,  sealed  herme- 
tically at  one  end.  Coat  the  closed  end 
With  clay,  for  about  an  inch,  and  let  the 
coating  dry.  Then  put  into  the  tube  the 
mixture  of  the  powder  and  its  flux,  and 
if  any  should  adhere  to  the  inner  surface, 
let  it  be  wiped  off  by  a  feather,  so  that 
the  inner  surface  of  the  upper  part  of  the 
tube  may  be  quite  clean  and  dry.  Stop 
die  end  of  the  tube  loosely,  with  a  little 
paper,  and  heat  the  coated  end  only,  on  a 
chafing-dish  of  red-hot  coals,  taking  care 
to  avoid  breathing  the  fumes.  The  arse- 
nic, if  present,  will  rise  to  the  upper  part 
of  the  tube,  on  the  inner  surface  of  which 
it  will  form  a  thin  brilliant  coating.  Break 
the  tube,  and  scratch  off  the  reduced  me- 
tal. Lay  a  little  on  a  heated  iron,  when, 
if  it  be  arsenic,  a  dense  smoke  will  arise, 
and  a  strong  smell  of  garlic  will  be  per- 
ceived. The  arsenic  may  be  farther  iden- 
tified, by  putting  a  small  quantity  between 
two  polished  plates  of  copper,  surround- 
ing it  by  powdered  charcoal,  to  prevent 
its  escape,  binding  these  tightly  together 
by  iron  wire,  and  exposing  them  to  a  low 
red  heat.  If  the  included  substance  be 
arsenic,^  white  stain  w  ill  be  left  on  the 
copper. 

(G.)  It  Aiay  be  proper  to  observe,  that 


I'OI 

neither  the  stain  on  copper,  nor  the  odour 
of  garlic,  is  produced  by  the  white  oxide 
of  arsenic,  when  heated  without  the  addi- 
tion of  some  inflammable  ingredient.  The 
absence  of  arsenic  must  not  therefore  be 
inferred,  if  no  smell  is  occasioned  by  lay- 
ing the  white  powder  on  a  heated  iron. 

The  late  celebrated  Dr.  Black  ascer- 
tained, that  all  the  necessary  experiments, 
for  the  detection  of  arsenic,  may  be  made 
on  a  single  grain  of  the  white  oxide ;  this 
small  quantity  having  produced,  when 
heated  in  a  tube  with  its  proper  flux,  as 
much  of  the  metal  as  clearly  established 
its  presence. 

If  the  quantity  of  arsenic  in  the  sto- 
mach should  be  so  small,  which  is  not  ve- 
ry probable,  as  to  occasion  death,  and  yet 
to  remain  suspended  in  the  washings,  the 
whole  contents,  and  the  water  employed 
to  wash  them,  must  be  filtered,  and  the 
clear  liquor  assayed  for  arsenic  by  the 
tests  (B.)  (C.)  (D.)  and  (E.) 

Discovery  of  Corrosive  Sublimate. 
Corrosive  sublimate  (the  muriate  of 
mercury)  next  to  arsenic,  is  the  most  vi- 
rulent of  the  metallic  poisons.  It  may  be 
collected  by  treating  the  contents  of  the 
stomach  in  the  manner  already  describ- 
ed ;  but  as  it  is  more  soluble  than  arse- 
nic, viz.  in  about  19  times  its  weight  of 
water,  no  more  water  must  be  employed 
than  is  barely  sufficient,  and  the  washings 
must  be  carefully  preserved  tor  examina- 
tion. 

If  a  powder  should  be  collected,  by 
this  operation,  which  proves,  on  examina- 
tion, not  to  be  arsenic,  it  may  be  known  to 
be  corrosive  sublimate  by  the  following- 
characters. 

(A.)  Expose  a  small  quantity  of  it, 
without  any  admixture,  to  heat,  in  a  coat- 
ed glass  tube,  as  directed  in  the  treat- 
ment of  arsenic.  Corrosive  sublimate 
will  be  ascertained  by  its  rising  to  the  top 
of  the  tube,  lining  the  inner  surface  in 
the  form  of  a  shining  white  crust. 

(B.)  Dissolve  another  portion  in  distilled 
water ;  and  it  may  be  proper  to  observe 
how  much  of  the  salt  the  water  is  capa- 
ble of  taking  up. 

(C.)  To  the  watery  solution  add  a  little 
lime-water.  A  precipitate  of  an  orange- 
yellow  colour  will  instantly  appear. 

(D.)  To  another  portion  of  the  solution 
add  a  single  drop  of  a  dilute  solution  of 
carbonate  of  potash  (salt  of  tartar).  A 
white  precipitate  will  appear ;  but,  on  a 
still  farther  addition  of  alkali,  an  orange- 
coloured  sediment  will  be  formed. 

(E  )  The  carbonate  of  soda  has  similar 
effects. 

(F.)  Sulphuretted  water  throws  down 


POI 


POl 


A  dark-coloured  sediment,  which,  when 
dried  and  strongly  heated,  is  wholly  vo- 
latilized, without  any  odour  of  garlic. 

The  only  mineral  poison  of  great  viru- 
lence that  has  not  been  mentioned,  and 
which,  from  its  being  little  known  to  act 
as  such,  it  is  very  improbable  w  e  should 
meet  with,  is  the  carbonate  of  barytes. 
This,  in  the  country  where  it  is  found,  is 
employed  as  a  poison  for  rats,  and  there 
can  be  no  doubt  would  be  equally  destruc- 
tive to  human  life.  It  may  be  discovered 
by  dissolving  it  in  muriatic  acid,  and  by 
the  insolubility  of  the  precipitate  which 
this  solution  yields  on  adding  sulphuric 
acid,  or  sulphate  of  soda.  Ban  tic  salts, 
if  these  have  been  the  means  of  poison, 
will  be  contained  in  the  water  employed 
to  wash  the  contents  of  the  stomach,  and 
will  be  detected,  on  adding  sulphuric 
acid,  by  a  copious  precipitate. 

Method  of  detecting  Copper  or  Lead. 

Copper  and  lead  sometimes  gain  admis- 
sion into  articles  of  food,  in  consequence 
of  the  employment  of  kitchen  utensils  of 
these  materials. 

I.  If  copper  be  suspected  in  any  liquor, 
its  presence  will  be  ascertained  by  adding 
a  solution  of  pure  ammonia,  which  wiii 
strike  a  beautiful  blue  colour.  If  the  so- 
lution be  very  dilute,  it  may  be  concentrat- 
ed by  evaporation  ;  and  if  the  liquor  con. 
tain  a  considerable  excess  of  acid,  like 
that  used  to  preserve  pickles,  as  much  of 
the  alkali  must  be  added  as  is  more  than 
sufficient  to  saturate  the  acid. 

IL  Lead  is  occasionally  found,  in  suffi- 
cient quantity  to  be  injurious  to  health,  in 
water  that  has  been  kept  in  leaden  ves- 
sels, and  sometimes  even  in  pump-water, 
in  consequence  of  this  metal  being  used 
in  the  construction  of  the  pump.  Acetate 
of  lead  has  also  been  known  to  be  frau- 
dulently added  to  bad  wines,  with  the 
view  of  concealing  their  defects. 

Lead  may  be  discovered  by  adding,  to 
a  portion  of  the  suspected  water,  about 
half  its  bulk  of  water  impregnated  with 
sulphuretted  hydrogen  gas.  If  lead  be 
present,  it  will  be  manifested  by  a  dark- 
brown,  or  blackish  tinge-  This  test  is  so 
delicate,  that  water,  condensed  by  the 
leaden  worm  of  a  still-tub,  is  sensibly  af- 
fected by  it.  It  is  also  detected  by  a  simi- 
lar effect  ensuing  on  the  addition  of  sul- 
phuret  of  ammonia,  or  potash. 

The  competency  of  this  method,  howe- 
ver, to  the  discovery  of  very  minute  quan- 
tities of  lead,  has  been  lately  set  aside  by 
the  experiments  of  Dr.  Lambe,  the  author 
of  a  skilful  analysis  of  the  springs  of  I.e- 
mington  Priors/near  Warwick.  By  new 
methods  of  examination,  he  has  detected 


the  presence  of  lead  in  several  spring-wa- 
ters, that  manifest  no  change  on  the  addi- 
tion ot  the  sulphuretted  test;  and  has 
found  that  metal  in  the  precipitate,  sepa- 
rated from  such  waters  by  the  carbonate 
of  potash  or  of  soda.  In  operating  on 
these  waters,  Dr.  Lambe  noticed  the  fol- 
lowing appearances. 

(a)  The  test  forms  sometimes  a  dark 
cloud,  with  the  precipitate  affected  by  al- 
kalies, which  has  been  redissolved  in  ni- 
tric acid. 

{b)  Though  it  forms,  in  other  cases,  no 
cloud,  the  precipitate  itself  becomes  dark- 
ened by  the  sulphuretted  test. 

(c)  The  test  forms  a  white  cloud,  treat- 
ed with  the  precipitate  as  in  (a).  These 
two  appearances  may  be  united. 

(d)  The  test  neither  forms  a  cloud,  nor 
darkens  the  precipitate. 

(e)  In  the  cases  (£),  (c),  (d),  heat  the 
precipitate,  in  contact  with  an  alkaline 
carbonate,  to  redness;  dissolve  out  the. 
carbonate  by  water;  and  treat  the  prtci. 
pitate  as  in  (a).  The  sulphuretted  test 
then  forms  a  dark  cloud  with  the  solution 
of  the  precipitate.  In  these  experiments, 
it  is  essential  that  the  acid,  used  to  redis- 
solve  the  precipitate,  shall  not  be  in  ex- 
cess; and  if  it  should  so  happen,  that 
excess  must  be  saturated  before  the  test 
is  applied.  It  is  better  to  use  so  little 
acid,  that  some  of  the  precipitate  may  re- 
main undissolved. 

(f)  Instead  of  the  process  (e)  the  pre- 
cipitate may  be  exposed  without  addition, 
to  a  red  heat,  and  then  treated  as  in  (a). 
In  this  case,  the  test  will  detect  the  metal- 
lic matter;  but  with  less  certainty  than 
the  foregoing  one. 

The  nitric  acid,  used  in  these  experi- 
ments, should  be  perfectly  pure ;  and  the 
test  should  be  recently  prepared,  by  satu- 
rating water  with  sulphuretted  hydrogen 
gas. 

Another  mode  of  analysis,  employed 
by  Dr.  Lamb,  consists  in  precipitating  the 
lead  by  muriate  of  soda;  but  as  muriate 
of  lead"  is  partly  soluble  in  water,  this  test 
cannot  be  applied  to  small  portions  of  sus- 
pected water.  The  precipitate  must  be, 
therefore,  collected  from  two  or  three  gal- 
lons, and  heated  to  redness  with  twice  its 
weight  of  carbonate  of  soda.  Dissolve 
out  the  soda;  add  nitric  acid,  saturating 
any  superfluity ;  and  then  apply  the  sul- 
phuretted test. 

The  third  process,  which  is  the  most 
satisfactory  of  all,  and  is  very  easy,  ex- 
cept for  the  trouble  of  collecting  a  large 
quantity  of  precipitate,  is  the  actual  re 
duction  of  the  metal,  and  its  exhibition  in 
a  separate  form.  The  precipitate  may  be 
mixed  with  its  own  weight  of  alkaline 


POL 


POR 


carbonate,  and  exposed  either  with  or 
without  the  addition  of  a  small  propor- 
tion of  charcoal,  to  a  heat  sufficient  to 
melt  the  alkali  On  breaking-  the  cruci- 
ble, a  small  globule  of  lead  will  be  found 
reduced  at  the  bottom.  The  precipitate 
from  about  fifty  gallons  of  water  yielded 
Dr.  L.  about  two  grains  of  lead. 

For  discovering  the  presence  of  lead  in 
wines,  a  test,  invented  by  Dr.  Hahnemann, 
and  known  by  the  title  of  Hahnemann's 
wine-test,  may  be  employed.  This  test 
is  prepared  by  putting  together,  into  a 
small  phial,  sixteen  grains  of  sulphuret  of 
lime,  prepared  in  the  dry  way,  and  20 
grains  of  acidulous  tartrite  of  potash 
(cream  of  tartar).  The  phial  is  to  be  fill- 
ed with  water,  well  corked,  and  occasion- 
ally shaken  for  the  space  of  ten  minutes. 
When  the  powder  has  subsided,  decant 
the  clear  liquor,  and  preserve  it,  in  a  well- 
stopped  bottle,  for  use.  The  liquor,  when 
fresh  prepared,  discovers  lead  by  a  dark- 
coloured  precipitate.  A  further  proof  of 
the  presence  of  lead  in  wines,  is  the  oc- 
currence of  a  precipitate  on  adding  a  so- 
lution of  the  sulphate  of  soda. 

The  quantity  of  lead,  which  has  been 
detected  in  sophisticated  wine,  may  be 
estimated  at  forty  grains  of  the  metal  in 
every  fifty  gallons. 

When  a  considerable  quantity  of  ace- 
tate of  lead  has  been  taken  into  the  sto- 
mach, (as  sometimes,  owing  to  its  sweet 
taste,  happens  to  children)  after  the  exhi- 
bition of  an  active  emetic,  the  hydro-sul- 
phurate of  potash  or  of  ammonia  may  be 
given  ;  or  a  solution  of  the  common  sul- 
phuret. 

In  cases  of  the  accidental  swallowing  of 
sulphuric  acid,  which  also  sometimes 
happens  to  children,  M.  Fourcroy  recom- 
mends the  speedy  administration  of  a  so- 
lution of  soap,  or  a  mixture  of  carbonate 
of  magnesia  or  carbonate  of  lime  (com- 
mon chalk)  with  water. 

POLARITY  of  the  Magxet.  See 
Magnetism. 

POLISHING. — We  have  heretofore  no- 
ticed the  use  of  different  substances  for 
polishing  bodies.  It  is  hardly  necessary, 
therefore, to  say  much  in  this  piace.  Be- 
sides the  use  of  different  mineral  and  ve- 
getable bodies,  we  shall  only  observe,  that 
one  of  the  most  proper  articles,  in  this  re- 
spect, is  the  Asphadelus  iuteus,  L.  or  the 
Common  Yellow  Asphodel  ...  The  stalks  of 
this  plant  are  somewhat  thicker  than  a 
goose-quill ;  and  when  dipped  in  Colco- 
thar,  or  Crocus  Afartis,  (which  may  be 
had  of  the  druggists,)  reduced  to  a  paste 
with  sweet-oil,  and  properly  applied  to 
iron  and  brass  utensils,  will  not  only  ren- 


der them  exceedingly  bright,  but  also 

prove  a  better  preservative  from  the  rust, 
than  sand-paper,  or  other  rough  mate- 
rials. 

POPPY.  SeeOnuM. 
POPPY-SEED  OIL.    See  On.. 
PONDEROUS  EARTH.    See  Bary* 
tes,  article  Earths 

PORCELAIN.  See  Pottery. 
PJRCELA1N,Reaumur*s.  See  Glass. 
PORK,  is  the  flesh  of  hogs  killed  for 
culinary  purposes.  For  sundry  observa- 
tions on  the  means  of  curing  pork,  as  well 
us  other  animal  substances,  we  refer  to 
the  articles  Beef,  Bacon,  Pickle,  Ice 
We  shall  add,  however,  the  following 
mode  of  pickling  pork,  which  is  mostly 
adopted  in  this  country. 

First,  cut  the  flesh  into  long  pieces, 
about  an  inch  and  a  half  thick;  and,  after 
sprinkling  it  with  salt,  and  suffering  it  to 
remain  in  that  state  lor  24  hours,  these 
slices  are  next  dried  in  stoves  till  they  ac- 
quire  a  bony  hardness,  and  a  deep  brown 
colour.  Pork,  treated  in  this  manner,  if 
packed  in  casks,  may  be  preserved  for  up- 
wards of  a  whole  year ;  and,  when  soak- 
ed in  luke-warm  water,  becomes  plump, 
and  has  a  rosy  appearance.  It  likewise 
possesses  a  grateful  flavour  under  the  va- 
rious forms  of  cookery,  and  is  relished  by 
the  most  delicate  palate. 

Beside  the  usual  manner  of  curing  pork 
with  bay-salt,  some  housewives  add  juni- 
per-berries, pepper,  nitre,  and  other  anti- 
septic substances  Saltpetre,  when  used 
in  small  proportions,  is  peculiarly  calcu- 
lated to  resist  putrefaction.  See  Pic- 
kle 

PORTABLE  VINEGAR— Several  me- 
thods have  been  proposed  to  render  vine- 
gar portable  ;  but  the  custom  is  not  preva- 
lent, and  we  think,  when  used,  but  of  little 
advantage.  The  concentration  of  vinegar 
by  congelation,  and  by  distillation,  in  order 
to  free  it  of  water,  has  been  preferred  : 
the  decomposition  of  certain  acetites  by 
distillation,  in  order  to  obtain  acetic  acid, 
or  radical  vinegar,  is  the  best  mode  of  con- 
centrating the  acid,  or  of  preserving  it  in 
a  state  necessary  for  considerable  dilu- 
tion. One  ounce  of  which  will  afford,  by 
dilution  with  water,  better  than  a  pint  of 
strong  vinegar.  The  following  receipt 
for  making  portable  vinegar  is  given  by 
Imison. 

Take  green  grapes,  and  stamp  thera, 
and  put  some  vinegar  to  them,  making  it 
into  a  sort  of  paste  or  dough,  whereof 
you  form  little  loaves,  and  lay  them  in  the 
sun  to  dry.  When  they  are  thoroughly 
dry,  put  them  up  for  use.  You  steep 
these  little  loaves  in  as  much  wine  as  you 
think  sufficient  for  present  use,  and  you 


POT 


POT 


have  a  very  good  strong  vinegar.  See 
Vinegar. 

PORTER.— Although  we  have  given 
some  general  observations  on  beer  and 
porter,  in  the  article  on  brewing,  )  et  we 
deem  it  of  importance  to  introduce  in  this 
place  the  following  recipe,  which  we  have 
taken  from  Child's  late  treatise,  entitled, 
Every  man  his  own  Brewer,  viz. 

One  peck  of  malt, 

A  quarter  of  a  pound  of  liquorice-root, 
Spanish  juice, 
Essential  bina, 
Colour, 

Half  a  pound  of  treacle, 

A  quarter  of  a  pound  of  hops, 

Capsicum  and  ginger. 
These  articles  are  to  be  managed  as  di- 
rected in  the  article  Brewing,  and  will 
produce  six  gallons  of  good  porter. 

For  the  information  of  those  who  may 
be  totally  unacquainted  with  the  process 
of  brewing  porter,  we  shall  add  a  short 
explanation  of  the  manner  in  which  the 
essentia  bina  and  the  colour  are  prepared. 
In  order  to  procure  the  first  of  these  in- 
gredients, a  quarter  of  a  pound  of  moist 
sugar,  should  be  boiled  in  an  iron  vessel, 
till  it  attain  to  the  consistence,  of  a  thick 
black  syrup,  which  is  remarkably  bitter. 
The  colour  is  produced  by  boiling  a  simi- 
lar quantity  of  moist  sugar,  till  it  acquire 
a  taste  between  sweet  and  bitter  :  it  im- 
parts the  fine  mellow  tint,  that  is  so  much 
admired  in  good  porter. 

POTASH.  Pearl  ash,  Salt  of 
Tartar.  In  this  article  we  shall  first 
treat  of  the  method  of  procuring  the  ve- 
getable fixed  alkali,and  the  different  forms 
under  which  it  appears  in  commerce,  and 
domestic  use.  By  the  name,  potash  is 
now  commonly  distinguished,  that  alkali 
which  was  formerly  called  fixed,  to  dis- 
tinguish it  from  ammonia,  and  vegetable, 
as  it  was  supposed  to  be  peculiar  to  that 
kingdom :  though  it  has  been  found  of  late 
in  various  stones,  and  in  small  quantities 
even  in  animal  substances ;  at  a  red- 
heat  it  is  volatilized.  From  the  article 
known  in  commerce,  by  the  name  of  pot- 
ashes,  which  consist  chiefly  of  this  alkali, 
though  in  a  very  impure  state,  the  French 
neologists  termed  the  alkali  potasse, 
whence  our  potash  is  derived ;  though 
this  has  the  inconvenience  of  rendering 
the  pure  alkali,  to  be  confounded  with 
the  heterogenous  compound,  from  which 
it  is  extracted.  The  names  of  lixivia,  giv- 
en it  by  Dr.  Black,  tartarin,  by  Kirwan, 
vegalkali,  by  Dr.  Pearson,  and  kali,  by 
the  London  college,  are  not  open  to  this 
objection;  but  neither  of  them  has  been 
adopted  by  other  chemists.  Some  have 
retained  the  French  word  without  altera- 


tion, others  have  altered  its  termination 
merely  ;  and  perhaps  potassa  is  the  pre- 
ferable term,  though  we  have  followed 
the  current  of  the  more  general  usage. 

The  vegetable  fixed  alkali,  was  so  nam- 
ed by  the  chemists,  of  the  last  and  former 
ages,  because  it  was  procured  in  large 
quantities  from  vegetable  substances,  and 
was  in  no  case  supposed  to  be  of  mineral 
origin.  From  certain  late  analysis,  how- 
ever, by  Klaproth  and  other  able  chemists, 
it  has  been  discovered  to  enter,  as  an  es- 
sential ingredient,  into  the  composition  of 
leucite,  lepidolite,  and  a  few  other  mine- 
rals, which  are  by  none  suspected,  of  de- 
riving their  origin  from  organized  bodies. 
But  though  the  existence  of  potash  in  a 
mineral  state  has  been  thus  demonstrated, 
yet  it  is  so  small  in  quantity,  and  so  diffi- 
cultly procurable,  that  all  the  vast  sup- 
plies of  this  substance,  which  civilized 
life  requires,  have  as  yet  been  entirely  ob- 
tained, from  the  combustion  of  vegeta- 
bles. 

If  the  woody  or  annual  stems  of  vege- 
tables, that  have  grown  in  soils  unimpreg- 
nated  with  common  salt,  after  being  suffi- 
ciently dried,  are  set  fire  to,  the  watery, 
the  resinous,  the  oily,  the  acid  and  carbo- 
naceous portions,  ale  volat'-lized  and  dis- 
sipated, in  a  state  of  more  or  less  com- 
plete decomposition,  and  there  remains 
behind,  a  reddish  or  whitish  powder,  call- 
ed ash  or  ashes  :  consisting  chiefly  of  the 
earthy,  and  metallic  ingredients  of  the  ve- 
getables, together  with  a  variable  propor- 
tion of  sub-carbonat  of  potash.  By  lixi- 
viation  with  hot  or  cold  water,  the  alka- 
line part  is  dissolved  out,  and  this  solu- 
tion when  boiled  down  to  dryness,  leaves 
behind  a  dark  brown  saline  mass,  con- 
sisting of  the  carbonated  potash,  coloured 
by  a  small  portion  of  vegetable  inflamma- 
ble matter  ;  and  in  this  state  it  is  known 
in  the  English  market,  by  the  name  of 
potash.  Calcination  at  a  moderate  red 
heat,  completely  burns  off  the  colouring 
particles,  and  the  salt  becomes  of  a  spun- 
gy texture,  and  beautiful  bluish  white 
tinge,  and  is  then  called  pearlash.  Such 
is  in  general,  the  process  by  which  the 
vegetable  fixed  alkali,  is  separated  from 
the  substances  with  which  it  is  combined 
by  nature,  and  prepared  for  use.  We  shall 
now  proceed  to  describe,  more  at  large 
the  different  methods  of  extracting  this 
salt,  together  with  the  precautions  that 
are  necessary  to  secure  the  greatest  suc- 
cess. 

The  simplest  and  rudest  preparation  of 
potash,  is  called  ash-balls  in  England,  and 
weed-ash  in  Ireland.  It  cannot  be  said, 
properly  speaking,  to  be  an  article  of  com- 
merce, although  a  considerable  quantity 


POT 


POT 


is  annually  made  by  the  peasantry  of  both 
countries,  and  disposed  of  among  the 
neighbouring"  farmers  and  bleachers.  The 
vegetable  from  which  this  impure  alkali, 
is  produced  is  the  common  fern  or  brakes, 
(Uteris  aquilina  Lin)  Many  rough  and 
heathy  districts,  are  entirely  covered  with 
this  plant,  which  when  it  has  attained  its 
full  growth,  (which  happens  about  the 
middle  of  July)  is  cut  down,  and  after 
being  half-dried  in  the  open  air,  is  gather- 
ed into  small  heaps  and  kindled.  The 
combustion  proceeds  slowly,being  accom- 
panied by  a  smothering  smoke,  and  little 
or  no  flame,  till  the  whole  is  reduced  to 
a  reddish  gray  ash  i  this  being  carefully 
collected,  is  sprinkled  with  a  little  water, 
and  then  moulded  by  hand  into  balls,  from 
three  to  four  inches  in  diameter,  which 
when  they  have  acquired  a  certain  hard- 
ness and  solidity,  by  drying  in  the  sun, 
are  ready  for  sale.  In  Ireland,  thistles, 
docks  and  weeds  of  all  kinds,  are  mixed 
with  the  fern,  and  the  ashes  are  disposed 
of,  in  their  loose  pulverulent  state,  with- 
out any  further  preparation.  According 
to  Dr.  Home,  fern-ashes  contain  about  one- 
ninth  of  their  weight  of  salt,  consisting 
principally  of  sub-carbonat,  and  sulphat 
of  potash.  One  thousand  parts  of  the 
plant  cut  in  August,and  thoroughly  dried, 
afford  36.46  of  ashes,  from  which  are  ob- 
tained by  lixiviation  4.25  of  salt.  The  com- 
mon Irish  weed  ashes,  have  been  analized 
by  Mr.  Kirwan  ;  and  when  deprived  of 
their  water  by  a  red  heat,  appear  to  con- 
tain one  part  of  salt,  for  three  and  an  half 
parts  of  ash  of  this  the  free  alkaline  por- 
tion however,  as  deduced  from  the  quan- 
tity of  alum,  decomposed  by  the  lixivium, 
amounted  only  to  one-twenty-second  of 
the  whole. 

The  potash  of  commerce,  or  black  pot- 
ash, as  it  is  also  called,  is  universally  pro- 
cured from  the  combustion  of  wood  ;  and 
therefore  its  preparation  can  only  be  un- 
dertaken with  success,  in  those  uncleared 
countries,  in  which  are  vast  natural  fo- 
rests, and  where  from  the  badness  of 
roads,  and  imperfection  of  water  commu- 
nication, the  value  of  timber  is  no  more 
than  that  of  the  labour  employed  in  felling 
it.  The  only  districts  in  Europe,  in  which 
any  considerable  quantity  of  potash  is 
made,  are  the  mountainous  forests  of  Ger- 
many, and  the  extensive  woodland  tracts 
of  Poland  and  Russia.  The  British  mar- 
ket is  principally  supplied  from  the  Unit- 
ed States  of  North  America ;  a  country 
in  which  from  its  rapid  increase  in  popu- 
lation, there  is  a  constant  demand  for 
cleared  land  for  the  purpose  of  cultiva- 
tion, and  therefore  timber  is  looked  upon 

vol..  ii. 


ralher  as  an  incumbrance,  than  as  con- 
tributing either  to  the  beauty,  or  value  of 
the  ground  on  which  it  stands. 

The  most  wasteful  method  of  manufac- 
turing potash, is  that  practised  by  the  Ame- 
ricans, partly  on  account  of  the  ignorance 
of  the  people,  by  whom  it  is  prepared,  but 
principally  because  this  employment  is  car- 
ried on  rather  as  subsidiary  to  clearing  the 
ground  for  agriculture  than  on  its  own  ac- 
count. The  wood  as  soon  as  it  is  sufficiently 
dry  to  burn,is  collected  into  large  piles,and 
reduced  to  ashes:  these  ashes  are  then  put 
into  a  wooden  cistern,  with  a  plug  at  the 
bottom  of  one  of  the  sides,  and  a  quanti- 
ty of  water,  sufficient  to  make  a  strong 
lixivium  is  added  :  after  standing  for  an 
hour  or  two,  the  plug  is  withdrawn,  and 
the  water  holding  the  potash  in  solution 
runs  clear  out,  leaving  the  earthy  part  still 
impregnated  with  alkali  in  the  cistern. 
This  solution  is  then  evaporated  to  dry- 
ness in  iron  pans,  and  hastily  fused  into 
compact  reddish  brown,  masses  of  semi- 
caustic  potash,  in  which  state  it  is  fit  for 
the  market. 

In  Germany,  where  potash  is  prepared 
(on  its  own  account,)  and  where  a  greater 
degree  of  intelligence  and  economy  is 
practised,  the  general  method  of  proceed- 
ing is  the  same  as  that  just  mentioned, 
but  with  such  variations  as,  though  seem- 
ingly of  little  consequence,  materially  aug- 
ment the  produce  of  alkali.  Care  is  taken 
to  select  such  kinds  of  wood  as  are  the 
richest  in  potash;  the  combustion  is  slow- 
er, and  of  course  the  temperature  lower, 
in  consequence  of  which  but  little  is  lost 
by  volatilization ;  the  lixiviations  of  the 
ashes,  are  also  judiciously  repeated  till 
the  whole  of  the  alkali  is  extracted. 

The  common  Russian  potash  is  the  im- 
purest  of  ali,  containing  nearly  one  half 
its  weight  of  earth,  and  is  thus  prepared. 
A  large  pit  is  dug,  into  which  are  thrown 
burning  brands,  and  the  smaller  extre- 
mities of  the  branches,  and  when  the  whole 
is  well  kindled,  the  pit  is  filled  up  with 
logs  and  other  large  pieces,  which  at 
length,  though  very  slowly,  are  reduced 
to  ashes.  The  coarser  part  of  the  ashes, 
is  then  separated  by  sifting  from  the  finer; 
all  the  alkali  that  it  contains,  is  procured 
by  lixiviation  ;  and  this  liquor  is  mixed 
with  the  remainder  of  the  ashes,  and 
worked  together  into  a  kind  of  paste.  A 
pile  is  then  built  of  alternate  strata,  of 
wood  and  this  paste,  and  being  set  fire  to, 
the  whole  is  again  reduced  to  ashes.  This 
process  is  repeated  several  times,  till  the 
ashes  begin  to  clot  and  become  hard :  the 
most  compact  pieces  being  then  selected, 
are  packed  up  for  sale  without  any  fur^ 


POT 


POT 


thcr  preparation ;  the  rest  are  lixiviated 
and  boiled  down  to  dryness,  in  the  usual 
manner. 

In  some  parts  of  Germany,  potash  is 
made  from  the  empyreumatic  acid,  pro- 
duced from  wood, while  burning1  into  char- 
coal. By  means  of  wide  tubes  of  plate  iron 
or  copper,  the  acid  and  oil  which  would 
otherwise  be  dissipated  in  the  air,  are 
collected  ;  the  watery  acid  part  being-  then 
separated  from  the  other,  is  evaporated 
to  dryness,  and  the  residuum  by  calci- 
nation, affords  an  ash  extremely  rich  in 
alkali. 

Potash  is  converted  into  a  much  purer 
alkaline  salt,  called  pearl-ash,  by  calcina- 
tion :  for  this  purpose,  the  potash  broken 
into  moderately  small  pieces,  is  spread  on 
the  floor  of  a  reverberatory  furnace,  and 
being  then  kept  red-hot,  but  not  melted, 
for  an  hour  or  two,  stirring  it  occasionally 
with  an  iron  rake,  all  the  carbonaceous 
and  colouring  particles  are  burnt  out,  and 
there  remains  behind,  a  dry  porous  and 
considerably  caustic  salt,  extremely  deli- 
quescent, and  from  its  bluish  white  colour 
called  pearl-ash. 

Dr.  Percival  has  proposed  the  following 
method,  for  procuring  pot-ash  from  the 
putrid  water  which  runs  from  dung-hills ; 
as  being  entitled  to  particular  attention. 
His  process  is  very  simple  :  it  consists  in 
evaporating  the  fluid  part,  and  in  calcin- 
ing the  impure  salt,  till  the  foul  or  extra- 
neous ingredients,  are  almost  entirely  dis- 
sipated by  the  fire.  From  24  wine-pipes 
of  such  liquor,  Dr.  Percival  obtained  nine 
cwt.aud  40  lbs.  of  saleable  pot-ash,  which 
was  valued  at  21.  2s.  per  cwt ;  the  expense 
of  the  whole  process,  amounted  to  41.  9s.' 
The  salt  thus  procured,  has  a  greyish- 
white  appearance ;  and  is,  when  broken, 
of  a  hard  spongy  texture  :  it  is  slightly 
affected  by  moist  air ;  but,  if  it  be  kept  in 
a  dry  apartment  near  the  fire,  a  powder 
is  formed  on  its  surface.  Lastly,  this  spe- 
cies of  pot-ash  contains,  according  to  Dr. 
Percival's  chemical  analysis,  such  a  pro- 


portion of  pure  alkali,  as  amounts  to  one- 
third  part  of  its  weight;  while  that  im- 
ported from  Russia,  yields  only  one- 
eighth. 

In  the  year  1796,  a  patent  was  granted 
to  Mr.  Iloakesly,  for  his  method  of  mak- 
ing pot-ash  ;  for  the  supply  of  all  manu- 
factures, in  which  the  foreign  salt  or  any 
alkaline  matter  is  useful.  The  ingredi- 
ents employed,  consist  of  English, Welch, 
Irish,  or  Scotch  kelp  ;  foreign  barilla  ; 
and  the  salts  obtained  from  soap-boilers' 
waste,  whether  by  evaporation',  or  by  cal- 
cination. The  materials  are  pulverized, 
and  thrown  into  a  furnace  of  a  peculiar 
construction,  where  they  are,  by  intense 
heat,  melted  into  a  liquid,  which  is  dis- 
charged through  a  channel  into  pots. — 
When  cold,  the  mass  assumes  the  appear- 
ance of  foreign  [pot-ash. 

Several  patents  have  been  obtained  in 
this  country,  for  manufacturing  potash, 
and  for  separating  sal  polychist,  which  is 
formed  in  the  boiling-  of  potash  ley,  owing 
to  the  presence  of  sulphat  of  potash  in  the 
liquor. 

It  has  been  thought  of  consequence  in 
an  economical  point  of  view,  to  discover, 
the  proportion  of  potash  afforded  by  dif- 
ferent vegetables,  and  many  analyses  have 
been  made  for  this  purpose.'  They  are 
however  for  the  most  part  uu satisfactory, 
as  they  indicate  only  the  quantity  <;i  solu- 
ble saline  ingredients, without  distinguish- 
ing the  carbonated  potash,  from  the  sul- 
phat and  muriat  of  potash,  wnh  which  it 
is  always  mixed.  The  most  remarkable 
and  interesting  results,  will  be  found  in 
the  following  table,  part  of  which  were 
ascertained  by  a  Committee  of  the  Aca- 
demy of  Sciences  at  Paris,  and  the  rest  by 
the  chemists  whose  names  are  subjoined. 
One  hundred  parts  of  each  different  spe- 
cies, being  previously  thoroughly  dried, 
were  burned  by  an  open  fire  to  ashes,, 
which,  after  being  weighed,  were  accu- 
rately lixiviated,  till  all  their  saline  con- 
tents were  extracted. 


100  parts 


Fumitory  ... 

Wormwood 

Common  Nettle 

Sow  Thistle  (Sonchus  arvens.) 
Fern  .... 
Ditto  .... 
Stalks  of  Maise  , 
Ditto  Sunflower 
Buckwheat 
Vine  Branches 
Heath 


Ashes       Salt     Salt  from 
100  parts  of 
Jlshes 


21.9 

7.9 

36. 

Wiegleb- 

9.74 

7.3 

74.8 

Ditto 

10.67 

2.5 

23.4 

Pertuis 

10.5 

1.96 

18.6 

Ditto 

5. 

0.62 

12.5 

Ditto 

3.64 

042 

11.6 

Home 

8.86 

175 

19.7 

5.72 

2. 

34.9 

33.3 

3.4 

0.55  ' 

16.2 

11.5  Wildenheim 


POT 


POT 


100  parts 


Ashes 


Salt 


Salt  from 
100  parts  of 


Ashes 

foxglove  (digitalis  purpurea) 

33. 

Celandine  (Chelidonimn  maj.) 

• 

25. 

Nightshade  (atropa  bellad.) 

27. 

Boxwood 

2.6 

0.22 

7.8 

Sallow  .... 

2.8 

0.28 

10.2 

Elm  .... 

2.3 

0.39 

16.6 

Oak  

1.3 

0.15 

11.1 

Heche 

0.58 

0.12 

21.9 

Aspen  . 

1.22 

0.07 

6.1 

Fir        .  ... 

0.34 

0.04 

13  2 

Leipsic  econ.  Soc- 
Ditto 
Ditto 


Upon  a  cursory  inspection  of  this  table, 
it  appears  that  the  succulent  herbaceous 
plants,  afford  a  prodigiously  greater  pro- 
portion both  of  ashes  and  salt,  than  the 
.shrubby  and  ligneous  ones  :  it  is  however 
to  be  observed,  that  they  were  all  reduc- 
ed to  a  state  of  perfect  dryness,  before 
being  weighed,  a  circumstance  which  will 
in  a  considerable  degree,  account  for  the 
apparently  greater  quantity  of  salt,  con- 
tained in  the  succulent  vegetables  ;  for 
while  the  different  kinds  of  wood,  will  not 
lose  more  than  one-third,  or  even  one-fifth 
of  their  weight  in  drying,  fumitory  will 
probably  lose  nine-tenths,  or  even  more. 
It  is  not  likely  therefore,  that  it  can  ever 
be  worth  while,  as  some  speculators  have 
proposed,  to  be  at  the  expense  of  culti- 
vating fumitory  and  wormwood,  for  the 
sake  of  the  potash,  contained  in  their 
ashes. 

It  has  been  a  subject  of  enquiry,  among 
chemists, 'whether  the  pot-ash  that  is  ob- 
tained by  the  combustion  of  vegetables,  is 
formed  by  this  processor  only  disengaged 
by  the  decomposition  of  those  acids',  with 
which  it  was  before  united.  The  former 
of  these  opinions  was  adopted  by  Mac- 
quer,  and  many  of  the  eminent  chemists 
that  were  contemporary  with  him,  but  of 
late,  the  latter  opinion,  has  been  rather 
gaining  ground.  The  principal  argu- 
ments by  which  Macquer  supports  his 
theory  are  tlie  following.  1st.  When  ve- 
getables, capable  of  furnishing  much  al- 
kali by  combustion,  are  decomposed  in 
any  other  way,  no  other  saline  products 
are  obtained,but  liquid  and  concrete  acids. 
21.  When  vegetables  are  deprived  of  part 
of  their  acid  by  distillation,  the  produce 
of  alkali  is  proportionately  diminished. 
3d.  The  concrete  acids,  as  tartar,  are 
changed  into  alkali,  merely  by  combus- 
tion. 4th.  Plants  that  yield  little  or  no 
acid  in  distillation,  are  found  after  com- 
bustion, to  afford  little  alkali.  5th.  Plants, 
which  when  burnt  without  any  previous 
alteration,  yield  much  alkali,  if  burnt  after 


undergoing  complete  putrefaction,  afford 
no  alkali. 

In  opposition,  however,  to  these  argu- 
ments it  may  be  observed,  1st.  That  the 
native  concrete,  oxalic,  and  tartareous 
acids  have  been  proved  by  modern  che- 
mists to  be  acidulx,  or  in  other  words  to 
contain  potash,  though  not  to  full  satura- 
tion of  the  acid ;  and  therefore,  when  these 
are  burnt,  no  conversion  of  acid  into  alkali 
takes  place,  but  the  acid  being  volatilized 
and  decomposed,  the  alkali,  which  was 
before  masked  by  an  excess  of  acid,  now 
exhibits  itself  with  its  usual  characters. 
2d.  Nitre,  completely  formed,  has  been 
discovered  in  borage  and  some  other  ve- 
getables, therefore  the  existence  of  pot- 
ash,  the  alkaline  base  of  this  salt,  is  also 
necessarily  demonstrated.  3d.  Vauque- 
lin  has  shown  that  the  sap  of  trees  con- 
tains acetite  of  potash.  4th.  The  reason 
why  vegetables,  after  putrefaction,  yield 
no  alkali  is,  that  their  texture  being  broken 
up  by  this  process,  the  water  which  drains 
through  the  mass  dissolves  and  carries  off 
all  the  alkali  which  they  at  first  contain- 
ed. This  is  manifest  from  the  experi- 
ments of  Mr.  Birch,  who,  by  evaporating 
and  calcining  24  wine-pipes,  or  3024  gal- 
lons, of  dunghill  water,  procured  10481bs. 
of  good  marketable  potash.  We  may, 
therefore,  conclude  that  the  potash  ob- 
tained by  lixiviation  of  vegetable  ashes 
pre-existed  in  the  plants  themselves;  whe- 
ther this  alkali  is  formed  during  the  pro- 
cess of  vegetation,  or  is  only  imbibed 
from  the  earth  by  the  roots,  is  not  as  yet 
determined. 

The  varieties  of  pot  and  pearlash  which 
are  found  in  the  market  would,  no  doubt, 
on  analysis  afford  very  different  results, 
especially  with  regard  to  the  proportions 
of  earthy  matter,  of  water,  and  of  carbonic 
acid ;  it  is  not,  therefore,  perhaps,  much 
to  be  regretted,  that  we  possess  no  very- 
accurate  analysis  of  any  of  them. 

The  only  one  on  which  any  reliance 
can  be  placed,  is  of  Dantzic  pearlash  by 


POT 


POT 


Mr.  Kirwan,  in  which  are  contained 
about 

60.3  potash 

22.4  carbonic  acid 
7.2  water 

8  7  sulphated  potash 
0  7  muriated  ditto 
0.7  earth 

100.0 


But  if  the  analysis  of  any  particular 
sample  is  of  little  consequence,  generally 
speaking-,  yet  it  is  of  considerable  impor- 
tance both  to  the  manufacturer  and  che- 
mist, to  be  in  possession  of  a  compendious 
and  accurate  mode  of  ascertaining-  the 
contents  of  the  various  kinds  of  pot  and 
pearlash,  in  order  to  make  advantageous 
purchases  of  articles,  in  the  intrinsic 
worth  of  which  there  is  so  much  differ- 
ence. 

Mr.  Kirwan's  method  of  calculating  the 
proportion  of  real  alkali,  in  a  given  lixi- 
vium, from  the  quantity  of  precipitate 
which  it  throws  down  from  a  solution 
of  alum,  is  by  no  means  to  be  depended 
oil ;  far,  in  the  first  place,  the  siiex  and 
alumine  which  the  lixivium  holds  in  solu- 
tion, are  precipitated  together  with  the 
earth  of  alum ;  and,  in  the  second  place, 
So  much  depends  on  the  degree  of  wash- 
ing and  calcination  which  the  precipitate 
is  made  to  undergo,  that  from  equal  quan- 
tities of  alum  it  is  scarcely  possible  to  ob- 
tain equal  weights  of  earth.  Upon  the 
whole,  therefore,  perhaps  the  best  mode 
of  proceeding  is  as  follows. 

1st.  Prepare  a  diluted  sulphuric  acid 
by  mixing  the  concentrated  acid,  called 
oil  of  vitriol,  with  three  times  its  bulk  of 
distilled  water.  Then  test  it  by  taking 
100  grains  of  the  diluted  acid,  and  add- 
ing muriat  of  barytes  as  long  as  any  pre- 
cipitate falls  down.  The  sulphat  of  ba- 
rytes thus  prepared,  when  washed  with 
cold  water,  and  dried  at  a  low  red  heat, 
contains  33.3  per  cent,  of  sulphuric  acid ; 
hence  the  real  acid  in  any  quantity  of  the 
diluted  acid  is  readily  ascertained. 

2d.  Pulverize  50Q  grains  of  the  alkali 
under  examination,  and  digest  it  in  warm 
water,  adding  fresh  portions  of  this  fluid 
as  long  as  any  thing  is  dissolved.  Then 
put  all  the  solutions  together,  and  drop 
in  the  tested  sulphuric  acid  from  a  vial 
containing  a  known  weight  of  the  same, 
till  the  slightest  possible  excess  of  acid  is 
indicated  by  a  paper  tinged  with  litmus. 
After  this,  heat  the  mixture  to  expel  all 
the  carbonic  acid,  and  if  the  liquor  changes 
turmeric  paper,  add  a  few  drops  more  of 
sulphuric  acid  till  it  ceases  to  show  an 
excess  of  alkali.   Now  weigh  the  vial  of 


sulphuric  acid,  and  thus  ascertain  how 
much  has  been  expended  in  saturating  the 
alkali,  and  for  every  100  parts  of  real  acid 
(as  previously  determined  by  muriat  of 
barytes)  thus  employed,  set  down  121.2 
of  pure  potash.  The  alkali  being  the  part 
which  gives  value  to  the  whole,  this  is  all 
the  examination  which,  in  ordinary  cases, 
is  required ;  but,  it  the  analysis  is  to  be 
carried  further, 

3d.  Take  500  grains  more  of  the  alkali, 
dissolve  it  in  boiling  water,  and  pour  the 
solution  into  a  flask;  then  place  the  flask 
and  a  vial  containing  from  two  to  three 
ounces  of  pure  nitric  acid,  into  one  scale 
of  an  accurate  balance  and  equipose  them. 
Afterwards  add  the  acid,  by  degrees,  to 
the  alkali,  as  long  as  any  effervescence 
takes  place,  and  the  loss  of  weight  indi- 
cates the  amount  of  carbonic  acid.  The 
solution  will  now,  probably,  crystallize ; 
a  sufficient  quantity  of  water  is,  therefore, 
to  be  added,  in  order  to  dissolve  the  crys- 
tals, and  nitrat  of  barytes  is  to  be  dropped 
in  so  long  as  any  precipitate  takes  place. 
100  parts  of  the  diied  sulphat  of  barytes 
thus  procured,  indicate  73.6  of  sulphated 
potash.  This  being  remove  1,  add  to  the 
clear  liquor  nitrat  of  silver  till  it  ceases  to 
be  decomposed.  100  parts  of  muriated 
silver  show  41.34  of  muriated  potash. 
Thus  the  saline  contents  are  all  of  them 
ascertained,  viz.  potash,  carbonic  acid, 
sulphat  and  muriat  of  potash.  The  earthy 
part  is  shown  in  the  insoluble  residue,  No. 
2,  and  in  the  precipitate  which  falls  down 
on  boiling  the  alkaline  liquor  after  its  sa- 
turation with  sulphuric  acid.  If  any  sul- 
phur is  contained  in  the  alkali,  as  is  the 
case  with  the  black  potash,  this  will  fall 
down,  together  with  the  earth,  upon  satu- 
ration with  sulphuric  acid,  and  is  sepa- 
rated from  the  earth  by  a  red  heat. 

Having  now  treated  of  the  impure  sub- 
carbonats  of  potash,  we  shall  conclude 
this  article  with  an  account  of  the  purer 
subcarbonats,  and  the  perfect  cai  bonatof 
potash. 

The  most  important  of  the  purer  sub- 
carbonats is  salt  of  tartar,  which  is  pre- 
pared in  the  wine  countries  in  considera- 
ble quantity,  and  is  the  kind  generally 
used  in  medicine.  The  lees  of  wine,  and 
the  tartar  that  is  deposited  on  the  sides 
of  the  casks,  are  put  into  small  bags  about 
a  foot  long,  and  subjected  to  a  strong 
pressure,  in  order  to  squeeze  out  all  the 
wine,  which  is  disposed  of  to  the  brandy 
distillers  ;  the  contents  of  the  bags  being 
carefully  taken  out,  without  breaking, 
form  masses  like  loaves,  which  are  dried 
in  the  sun,  and  then  piled  up  in  a  furnace 
with  alternate  strata  of  charcoal.  The 
fire  being  kindled,  and  the  draft  properly 


POT 


POT 


regulated,  the  acid  and  inflammable  mat- 
ter of*  the  tartar  is  burned  off  without 
fusing  the  alkaline  part ;  when  the  pro- 
cess therefore  is  finished,  the  loaves  re- 
main of  nearly  the  same  size  as  before, 
but  very  porous,  and  perfectly  white. 
Being1  then  broken  into  pieces,  they  are 
dissolved  in  hot  water,  and  the  clear  lixi- 
vium being-  evaporated  to  dryness,  and 
slightly  calcined,  is  fit  for  sale.  Two  and 
a  half  parts  of  tartar  yield  one  of  salt  of 
tartar. 

A  more  expeditious,  but  less  economi- 
cal, way  of  procuring-  salt  of  tartar,  is  to 
mix  equal  parts  of  crude  tartar  and  nitre, 
and  project  the  mixture  into  a  red  hot 
crucible.  A  rapid  deflagration  takes 
place,  the  nitric  acid,  and  the  combusti- 
ble parts  of  the  tartar  mutually  decom- 
pose each  other,  and  there  remains  behind 
the  alkaline  base  of  each,  united  with 
some  carbonic  acid.  This  pre  paration  is 
called  white  fiuxf  nitre  fixed  by  tartar,  ex- 
temporaneous potash. 

The  perfectly  saturated  carbonat  of  pot- 
ash has  not  been  known  to  chemists  long-cr 
than  the  time  of  Berg-man.  It  may  be  pre- 
pared in  two  ways :  the  first,  which  was 
discovered  by  Berthollet,  is  as  follows. 
Take  equal  parts  of  salt  of  tartar,  and 
carbonat  of  ammonia,  dissolve  the  whole 
in  warm  water,  then  pour  the  solution 
into  a  retort,  and  proceed  to  slow  distilla 
tion ;  the  potash  having  a  stronger  affinity 
for  carbonic  acid  than  ammonia  has,  de 
prives  this  latter  of  its  acid,  and  in  conse- 
quence, ammoniacal  vapour  is  given  out 
in  great  quantity :  when  this  ceases,  the 
rontents  of  the  retort  are  to  be  poured 
into  a  convenient  vessel,  where,  by  refri- 
geration, a  copious  deposition  of  crystal- 
lized carbonat  of  potash  will  take  place. 

The  other  method,  and  that  which  is 
generally  practised,  is  to  put  a  solution  of 
salt  of  tartar  into  an  apparatus  for  impreg- 
nating- water  with  carbonic  acid,  and  then 
to  throw  in  this  acid  till  the  alkali  is  quite 
saturated,  and  refuses  to  take  up  any 
more ;  on  opening-  the  barrel,  it  will  be 
found  lined  with  large  crystals  of  carbo- 
nated potash. 

As  alkaline  salts  are  of  great  importance 
in  the  several  arts,  the  proportion  of  ashes 
afforded  by  different  vegetables,  and  that 
of  alkali  by  each  vegetable,  has  of  late 
been  accurately  attended  to.  Kirwan  has 
therefore  presented  the  best  authenticated 
results  of  the  experiments  made  with  this 
view. 

One  thousand  lbs.  l6sj°f  lbs)f 
ashes,  salt. 


lbs.  of  lbs.  of 

ashes. 

salt. 

34. 

5.5 

29. 

2.26 

28. 

2.85 

23.5 

3.9 

135 

1.5 

12.2 

0-74 

5.8 

1.27 

3.4 

0.45 

36.46 

4  25  Home 

97.44 

73.  Wiegleii 

219. 

79.  Idem. 

One  thousand  lbs. 

Vine-branches  - 
Box 
Sallow 
Elm 
Oak 
Aspen 
Beech 
Fir  - 

Fern,  in  August 
Wormwood 
Fumitory  - 

Table  of  the  saline  product  of  one  thousand 
lbs.  of  ashes  of  the  folloxvhig  vegetables. 

Saline  products. 
Stalks  of  Turkey^  igg  lbg 

wheat,  or  mais^ 
Stalks   of  Sun-  )  ^ 

flower  3  - 

Vine  branches  162.6 
Elm  -  -  166 
Box  -  -  78 
Sallow  -  -  102 
Oak  -  -  HI 
Aspen  61 
Beech  -  -  219 
Fir  -       -  132 

Fern,  cut  in  Au-7  jjg  ^  or  125  according 

gust  5        C  t0  Wildenheim. 

Wormwood  -  748 
Fumitory  -  360 

Heath       -       -    115  Wildenheim. 


Stalks  of  Turkey")  g86 

wheat,  or  mais3 
San-flowers       -  57.2 


17.5 

20. 


On  these  tables  Kirwan  makes  the  fol- 
lowing remarks : 

1.  That,  in  general,  weeds  yield  more 
ashes,  and  their  ashes  much  more  salt, 
than  woods ;  and  that  consequently,  as  to 
salts  of  the  vegetable  alkali  kind,  as  pot- 
ash, pearlash,  cashup,  Sec,  neither  Ame- 
rica, Trieste,  nor  the  northern  countries, 
have  any  advantage  over  Ireland. 

2.  That  of  all  weeds,  fumitory  produces 
most  salt,  and  next  to  it  wormwood.  But 
if  we  attend  only  to  the  quantity  of  salt  in 
a  given  weight  of  ashes,  the  ashes  of 
wormwood  contain  most.  Trifolium  fibri- 
num  also  produces  more  ashes  and  salt 
than  fern. 

Most  of  the  experiments  on  woods 
were  made  in  France  by  order  of  govern- 
ment, under  the  inspection  of  the  over- 
seers of  the  saltpetre  works;  yet  these  are 
to  be  read  with  caution  by  those  who  at- 
tend to  the  quantity  of  alkali  with  respect 
to  bleachers.  For  as  sulphat  of  potash,  a 
salt  useless  to  bleachers,  is  as  serviceable 
to  the  makers  of  saltpetre  as  alkaline 
salts,  they  have  constantly  confounded 
one  with  the  other ;  but  the  experiments 
made  on  weeds  were  instituted  by  persons 


POT 


POT 


who  carefully  discriminated  these  salts. 
[Much  of  the  nitre  obtained  by  elixation 
of  the  nitre-beds  has  a  calcareous  basis. 
Sulphat  of  potash  will  change  this  into 
nitre  by  double  affinity,  for  the  alkali 
unites  with  the  nitric  aci'd,  which  gives  its 
calcareous  base  to  the  suiphuvic]  One 
hundred  grains  of  the  salt  of  wormwood 
contain  but  six  of  the  sulphat  of  potash, 
and  one  hundred  grains  of  the  salt  of  fu- 
mitory contain  fifteen.  All  alkaline  salts, 
unless  mixed  with  lime,  contain  also  one- 
fifth  at  least  of  carbonic  acid,  which  pro- 
duces no  other  eflect  in  bleaching  than 
that  of  restraining  their  activity. 

The  process  for  obtaining  pot  and  pearl 
ash  is  given  by  Kit  wan,  as  follows  : 

1.  The  weeds  should  be  cut  just  before 
they  seed,  then  spread,  well  dried,  and 
gathered  clean. 

2.  They  should  be  burned  wit  hin  doors 
on  a  grate,  and  the  ashes  laid  in  a  chest 
as  fast  as  they  are  produced.  If  any  char- 
coal be  visible,  it  should  be  picked  out, 
and  thrown  back  into  the  fire.  If  the 
weeds  be  moist,  much  coal  will  be  found. 
A  close  smothered  fire,  which  has  been 
recommended  by  some,  is  very  prejudi- 
cial. 

3.  They  should  be  lixiviated  with  twelve 
times  their  weight  of  boiling  wider.  A 
drop  of  the  solution  of  corrosive  sublimate 
will  immediately  discover  when  the  water 
ceases  to  take  up  any  more  alkali.  The 
earthy  matter  that  remains  is  said  to  be  a 
good  manure  for  clayey  soils. 

4.  The  ley  thus  formed  should  be  eva- 
porated to  dryness  in  iron  pans.  Two  or 
three  at  least  of  these  should  be  used,  and 
the  ley,  as  fast  as  it  is  concreted,  passed 
from  the  one  to  the  other.  Thus,  much 
time  is  saved,  as  weak  leys  evaporate 
more  quickly  than  the  stronger.  The  salt 
thus  procured  is  of  a  dark  colour,  and 
contains  much  extractive  mutter,  and 
being  formed  in  iron  pots  is  called  pot- 
ash. 

5.  This  salt  should  then  be  carried  to  a 
reverberatory  furnace,  in  which  the  ex- 
tractive matter  is  burnt  off*,  and  much  of 
the  water  dissipated :  hence  it  generally 
loses  from  ten  to  fifteen  per  cent,  of  its 
weight.  Particular  care  should  be  taken 
to  prevent  its  melting,  as  the  extractive 
matter  would  not  then  be  perfectly  con- 
sumed, and  the  alkali  would  form  such  a 
union  with  the  earthy  parts  as  could  not 
easily  be  dissolved.  Kirwan  adds  this 
caution,  because  Dr.  Lewis  and  Mr.  Dos- 
sie  have  inadvertently  directed  the  con- 
trary. This  salt,  thus  refined,  is  called 
pearlash,  and  must  be  the  same  as  the 
Dantzic  pearlash. 

The  French  call  the  refined  ash  potasse, 


and  the  unrefined  salin.  Kirwan  remarks, 
that  the  alkali  manufactured  in  the  above- 
mentioned  manner  may  not  be  sufficiently 
pure  for  the  earlier  operations  of  bleach- 
ing; but  by  the  addition  of  half  a  pound 
of  quicklime  to  every  hundred  of  the  salt, 
or  ten  pounds  for  every  ton,  it  will  be  ren- 
dered sufficiently  sharp.  There  is  no 
danger,  that  any  of  the  lime  will  remain 
in  the  ley;  but  "if  any  should,  it  will  im- 
mediately be  discovered  and  deposited  by 
the  addition  of  a  little  of  the  unmixed 
ley. 

For  the  most  economical  construction 
of  a  laboratory  and  furnaces  for  the  above 
operations,  Kirwan  refers  to  the  descrip- 
tion given  in  a  French  tract  called  L\lrt 
dc  fabriqutr  le  Suitn  et  la  Potasse,  which 
I  have  not  seen.  And  he  adds,  that  it 
would  be  no  inconsiderable  advantage  to 
perform  the  evaporation  by  a  fire  made  of 
vegetables,  the  ashes  of  which  might  af- 
terwards be  employed.  Pearlash,  as  he 
also  remarks,  is  frequently  tinged  green 
or  blue  from  manganese,  which  Scheele 
has  shown  to  exist  in  the  ashes  of  most 
vegetables.  When  the  alkali  is  calcined 
without  melting,  it  proves  perfectly  white, 
like  the  Dantiic  pearlash. 

To  obtain  this  alkali  pure,  two  parts  of 
quicklime  in  powder  are  added  to  one  ot 
pearlash;  as  much  water  as  wiil  slake  the 
lime  is  then  poured  on  ;  and  afterward 
more  water  is  added,  so  as  to  reduce  the 
whole  to  a  thin  consistence.  After  this 
has  stood  two  or  three  days,  stirring  it 
occasionally,  the  liquor  is  filtered  through 
a  large  glass  funnel,  the  ttibe  of  which  is 
obstructed  by  a  piece  of  linen ;  and  the 
residuum  is  "elutriated  on  the  filter  with 
more  water,  till  eight  or  ten  times  the 
weight  of  the  pearlash  have  passed 
through:.  In  this  process,  however,  the 
whole  of  the  carbonic  acid  is  not  extract- 
ed by  the  lime,  other  saline  matters  will 
be  held  in  solution,  and  a  portion  of  silex 
may  be  dissolved  by  means  of  the  alkali. 
Barytes,  however,  will  abstract  the  great- 
er part  of  the  carbonic  acid,  and  likewise 
the  sulphuric,  as  its  attraction  for  these  is 
more  powerful  than  that  of  lime. 

If  it  be  required  in  a  state  of  extreme 
purity,  Bertholiet  recommends,  to  evapo- 
rate this  solution  till  it  becomes  of  a  thick- 
ish  consistence,  add  about  an  equal  weight 
of  alcohol,  and  let  the  mixture  stand  some 
time  in  a  close  vesel.  Some  solid  matter, 
partly  crystallized,  will  collect  at  the  bot- 
tom ;  above  this  will  be  a  small  quantity 
of  a  dark  coloured  fluid;  and  on  the  top 
another,  lighter.  The  latter,  separated  by 
decantation,  is  to  be  evaporated  quickly 
m  a  silver  basin  in  a  sand  heat.  Glass,  or 
almost  any  other  metal,  would  be  cor- 


rox 


pot 


roded  by  the  potash.  Before  the  evapo- 
ration has  been  carried  far,  the  solution 
is  to  be  removed  from  the  fire,  and  suffer- 
ed to  stand  at  rest ;  when  it  will  again  se- 
parate into  two  fluids.  The  lighter,  being 
poured  oft",  is  again  to  be  evaporated  with 
4  quick  heat;  and  on  standing  a  day  or 
two  in  a  close  vessel  it  will  deposit  trans- 
parent crystals  of  pure  potash.  If  the  li- 
quor be  evaporated  to  a  pellicle,  the  pot- 
ash'will  concrete,  without  regular  crystal- 
lization.  In  both  cases  a  high  coloured 
liquor  is  separated,  which  is  to  be  poured 
oft";  and  die  potash  must  be  kept  careful- 
ly secluded  from  air. 

Mr.  lletiry  observes,  that  a  perfectly 
pure  solution  of  potash  will  remain  trans- 
parent on  the  addition  of  barytic  water, 
show  no  effervescence  with  dilute  sulphu- 
ric acid,  and  not  give  any  precipitate  on 
blowing  air  from  the  lungs  through  it  by 
means  of  a  tube. 

Mr.  Kirwan  examined  the  Dantzic  pearl 
ash.  It  is  exceedingly  white,  and  if  not 
exposed  to  the  air  very  hard.  Its  taste  is 
alkaline.  The  contents  of  various  speci- 
mens were  different,  but  at  a  medium  he 
found  the  pound  troy  to  consist  of 

Carbonic  acid     -       1290  grains 
Moisture       -       -  414 
Sulphat  of  potash     -    50  ) 
Muriat  of  potash    -  36 
Earth       -  -  38 

Potash  -  3477 

5760 

As  1he  examination  of  the  alkalies  of 
commerce  must  be  of  great  utility  to  the 
manufacturer,  but  is  very  tedious  in  the 
way  of  solution  and  evaporation,  Mr.  Kir- 
wan proposes  a  test  by  the  precipitation 
of  the  earth  from  alum,  by  a  solution  of 
these  sails. 

To  discover  whether  any  quantity  of 
fixed  alkali  worth  attention  exist  in  any 
saline  compound,  dissolve  one  ounce  of  it 
in  boiling  water,  and  into  this  solution  let 
fall  a  drop  of  the  solution  of  corrosive 
sublimate.  This  will  be  converted  into  a 
brick  colour  if  an  alkali  be  present,  or  into 
a  brick  colour  mixed  with  yellow  if  the 
substance  contained  lime. 

But  the  substance  used  by  bleachers 
being*  always  impregnated  by  an  alkali, 
the  above  trial  is  in  general  superfluous, 
except  for  the  purpose  of  detecting  lime. 
The  quantity  of  alkali  is  therefore  what 
they  should  chiefly  be  solicitous  to  deter- 
mine :  and  for  this  purpose, 

1.  Procure  a  quantity  of  alum,  suppose 
one  pound,  reduce  it  to  powder,  wash  it 
n  cold  water,  and  then  put  it  into  a  tea- 


pot, pouring  on  it  three  or  four  times  its 
weight  of  boiling  water. 

2.  Weigh  an  ounce  of  the  ash  or  alka- 
line substance  to  be  tried,  powder  it,  and 
put  it  into  a  Florence  flask  with  one  pound 
of  pure  water  (common  water  boiled  for 
a  quarter  of  an  hour,  and  afterwards  fil- 
tered through  paper,  will  answer)  if  the 
saline  substance  to  be  examined  be  of  the 
nature  of  barilla  or  potashes,  or  half  a 
pound  of  water  if  it  contain  but  little 
earthy  matter  or  pearlash.  Let  them  boil 
for  a  quarter  of  an  hour;  when  cool,  let 
the  solution  be  filtered  into  another  Flo- 
rence flask. 

3.  This  being  done,  gradually  pour  this 
solution  of  alum  hot  into  the  alkaline  so- 
lution also  heated.  A  precipitation  will 
immediately  appear.  Shake  them  well 
together,  and  let  the  effervescence,  if  any, 
cease  before  more  of  the  aluminous  solu- 
tion be  added.  Continue  the  addition  of 
the  alum  until  the  mixed  liquor,  when 
clear,  turns  syrup  of  violets,  or  paper 
tinged  blue  by  radishes,  or  by  litmus,  red. 
Then  pour  the  liquor  and  precipitate  on  a 
paper  filter  placed  in  a  brass  funnel,  and 
the  precipitated  earth  will  remain  on  the 
filter.  Pour  on  this  a  pound  or  more  of 
hot  water  gradually,  until  it  becomes 
tasteless.  Take  up  the  filter,  and  let  the 
earth  dry  in  it  until  they  separate  easilv. 
Then  put  the  earth  into  a  cup  of  Stafford- 
shire ware,  place  it  on  hot  sand,  and  dry 
the  earth  until  it  no  longer  adheres  either 
to  glass  or  iron ;  then  reduce  it  to  pow- 
der in  the  cup  with  the  glass  pestle,  and 
keep  it  a  quarter  of  an  hour  in  a  heat  from 
470°  to  500°. 

4.  The  earth  being  thus  dried,  throw  it 
into  a  Florence  cask,  and  weigh  it ;  then 
put  about  an  ounce  of  muriatic  acid  into 
another  flask,  and  place  this  in  the  same 
scale  as  the  earth,  and  counterbalance 
both  in  the  opposite  scale :  this  being  done, 
pour  the  acid  gradually  into  the  flask  that 
contains  the  earth ;  and  when  all  effer- 
vescence is  over  (if  there  be  any)  blow 
into  the  flask,  and  observe  what  weight 
must  be  added  to  the  scale  containing  the 
flasks  to  restore  the  equilibrium;  sub- 
tract this  weight  from  that  of  the  earth, 
the  remainder  is  a  weight  exactly  propor- 
tioned to  the  weight  of  mere  alkali  of  that 
particular  species  which  is  contained  in 
one  ounce  of  the  substance  examined ;  all 
besides  is  superfluous  matter. 

Kirwan  remarks,  that  alkalies  of  the 
same  species  may  thus  be  directly  com- 
pared, because  alkalies  of  different  spe- 
cies cannot  but  require  the  intervention 
of  another  proportion  ;  and  the  reason  he 
gives  is,  because  equal  quantities  of  alka- 


POT 


POT 


iies  of  different  species  precipitate  une- 
qual quantities  of  earth  of  alum.  Thus 
100  parts  by  weight  of  mere  potash  pre- 
cipitate 78  of  earth  of  alum ;  but  100 
parts  of  soda  precipitate  170.8  parts  of  j 


kaline  substances  or  ashes,  may  be  found 
by  this  test.  Attention  must  be  paid  to 
the  nature  of  the  alkali,  and  the  quantity 
of  earth,  a  determinate  portion  will  throw 
down  :  which  must  be  ascertained  as  to 


that  earth.    Therefore  the  precipitation  |  the  first  by  experiment,  and  as  to  the  lat- 


of  78  parts  of  earth  of  alum  by  potash 
denotes  as  much  of  this  as  the  precipita- 
tion of  170.8  of  that  earth  by  the  soda  de- 
notes of  the  soda.  Hence  the  quantities 
of  alkali  in  all  the  different  species  of  pot- 
ashes, pearl-ashes,  weed  or  wood-ashes, 
may  be  immediately  compared  by  the 
above  test,  as  they  all  contain  the  potash ; 
and  the  different  kinds  of  kelp  or  kelps 
manufactured  in  different  places,  and  the 
different  sorts  of  barilla,  may  be  thus  com- 
pared, because  they  ali  contain  the  soda; 
but  kelps  and  pot-ashes,  as  they  contain 
different  sorts  of  alkali,  can  only  be  com- 
pared together  by  means  of  the  propor- 
tion above  indicated. 

The  application  of  this  test  is  founded 
on  the  following1  principles  : 

1.  That  a  hot  solution  of  a  free  alkali, 
or  of  an  alkali  combined  only  with  carbo- 
nic acid  or  sulphur,  can  hold  no  terrene 
or  metallico-neutral  salt  in  solution ; 
though  it  may  alkalino-neutral  salt  or 
quick-lime,  if  the  alkali  be  free  from  car- 
bonic acid. 

2.  That  earth  of  alum  cannot  be  preci- 
pitated either  totally  or  partially  by  the  hot 
solutions  of  any  alkalino-neutral  salt,  and 
therefore  that  its  precipitation  is  always 
due  to  the  presence  of  a  free  alkali,  or  at 
least  of  an  alkali  combined  only  with  car- 
bonic acid  or  sulphur,  to  the  quantity  of 
which  it  is  always  proportional.  It  is  true, 
quick-hme  will  also  decompose  alum  ; 
but  the  presence  of  quick-lime  is  easily 
discovered,  by  the  addition  of  a  few  drops 
of  any  mild  alkaline  solution,  and  by  the 
same  means  as  easily  separated. 

3.  That  if  the  earth  of  alum,  take  up 
carbonic  acid  (which  would  increase  its 
weight,)  this  air  will  be  separated  by  the 
heat  employed  in  drying  it,  or  at  least  by 
the  muriatic  acid  poured  upon  it. 

Kirwan  says,  he  can  see  but  one  inac- 
curacy attending  this  test,  and  that  of  lit- 
tle moment ;  it  is  this,  if  the  alkali  contain 
sulphur  this  will  also  be  precipitated  with 
the  earth  of  alum,  and  increase  its  weight. 
The  limits  of  this  inaccuracy,  at  least  in 
common  cases,  scarcely  reach  two  or  three 
grains. 

Sulphur  is  easily  detected  in  an  alka- 
line solution,  by  saturating  it  with  an  acid; 
sulphuretted  hydrogen  is  generally  de- 
veloped, and  the  liquor  becomes  trou- 
bled. 

Not  only  the  proportion,  but^  also  the 
absolute  weight  of  alkali  in  different  al- 


ter by  fundamental  trials.  The  reader 
may  consult  an  essay  by  Dr.  Higgins,  on 
the  same  subject. 

Mr.  Davy  has  made  an  extraordinary 
discovery,  by  subjecting  potash  and  soda, 
to  the  action  of  a  powerful  galvanic  pile. 
Moistened  potash,  exposed  on  a  plate  of 
platina,  to  the  action  of  the  galvanic  cir- 
cle, was  decomposed  into  oxygen  and  a 
base,  that  in  some  of  its  properties  resem- 
bles the  metals.  This  detrudes  oxygen 
from  its  rank,  as  the  generator  of  acidity, 
since  it  appears  to  be  a  constituent  part 
of  both,  the  fixed  alkalies,  and  the  vola- 
tile alkalies  likewise,  and  consequently  to 
be  no  less  essential  to  alkalies,  than  to 
acids  ;  if  not  more  essential  to  them,  since 
we  know  of  some  substances  possessing 
acid  properties,  the  existence  of  oxygen  in 
which  is  at  least  very  doubtful,  if  not  dis- 
proved. This  experiment  has  been  con- 
firmed by  other  chemists. 

The  base  of  potash  thus  obtained  is 
highly  inflammable,  and  forms  an  amal-  * 
gam  with  mercury  :  but  it  is  so  far  from 
having  the  specific  gravity  of  metals,  that 
it  is  lighter  than  most  fluids,  its  gravity 
being  to  that  of  distilled  water,  only  as  six 
to  ten. 

At  the  freezing  point  it  is  hard,  brittle, 
and  when  broken  exhibits  facets,as  if  crys- 
tallized, when  examined  by  the  micros- 
cope. At  40°  it  is  scarcely  distinguish- 
able from  a  small  globule  of  quicksilver  ; 
at  60°  it  is  quite  fluid ;  and  at  a  heat  lit- 
tle below  redness,  it  is  volatile. 

It  is  extremely  greedy  of  oxygen,  ab- 
sorbing it  rapidly  from  the  atmosphere, 
and  resuming  the  alkaline  state.  If  amal- 
gamated with  twice  its  bulk  of  quicksilver, 
and  applied  to  iron,  silver,  gold  or  platina, 
these  metals  are  immediately  dissolved, 
and  converted  into  oxydes,  while  the  al- 
kali is  regenerated.  Glass  is  decomposed 
by  it,  the  basis  of  potash  combining  with 
its  alkali,  and  forming  a  red  oxyde,  in 
which  the  base  is  less  oxygenated  than  in 
potash.'  This  red  oxyde,  was  likewise 
procured  by  other  means. 

From  a  considerable  number  of  experi- 
ments, potash  appeared  to  consist  of  85 
parts  base,  and  15  of  oxygen. 

A  globule  of  the  base,  placed  on  a  piece 
of  ice,  burnt  with  a  bright  flame,  and  in- 
tense heat,  and  potash  was  found  in  the 
water,  from  the  melted  ice.  In  this  case 
as  well  as  when  a  globule  was  thrown 
into  'water,  a  considerable  quantity  of 


POT 


POT 


hydrogen  was  rapidly  evolved.  When  a 
globule  was  placed  on  a  piece  of  moist 
turmeric  paper,  it  appeared  instantly  to 
acquire  intense  heat,  but  moved  so  rapid- 
ly in  quest  of  the  moisture,  that  the  pa- 
per was  no  where  burned;  but  a  deep 
red  stain,  that  marked  its  course,  proved 
the  regeneration  of  the  alkali. 

From  the  avidity  of  the  metalloid  (as 
it  has  been  called)  for  oxigen,  it  is  not  ea- 
sy to  keep  it :  but  in  distilled  naphtha  a 
film  forms  round  it,  which  excludes  oxi- 
gen so  that  it  may  be  preserved  four  or 
live  days. 

Mr.  Charles  Sylvester,  and  some  other 
gentlemen,  have  repeated  Mr.  Davy's  ex- 
periments with  similar  results.  Mr.  Syl- 
vester, however,  always  found  a  small 
portion  of  black  matter  formed  at  the 
wire  coming  from  the  copper  end  of  the 
battery,  which  was  not  a  suboxide  of  the 
base,  for  it  remained  permanent  in  water 
several  weeks ;  and  it  did  not  appear  to 
be  charcoal.  In  one  of  this  gentleman's 
experiments,  the  metalloid  exploded,  and 
burst  the  glass  tube  in  which  it  was  en- 
closed ;  and  in  one  by  a  gentleman  at 
Tun  bridge,  it  deflagrated  suddenly,  and 
was  thrown  about  so  as  to  injure  his  eyes : 
it  should  not  be  attempted,  therefore, 
without  caution. 

Potash  forms  a  considerable  branch  of 
manufacture  in  the  United  States  ;  the 
quantity  annually  made  is  sufficient  for 
home  supply,  and  for  foreign  markets. 

POTASSIUM  —The  base  of  potash, 
a  peculiar  metal.    See  Potash. 

POTATOE  STARCH.    See  Starch. 

POTATOE,  various  uses  of'.—  Besides 
starch,  potatoes  will  afford  saccharine 
matter,  and  properly  prepared  will  yield 
spirit  by  distillation,  which  will  be  notic- 
ed hereafter. 

A  fine  size  may  be  prepared  from  pota- 
toes, which  will  answer  all  the  purposes 
of  that  in  common  use,  particularly  for 
whitening  cielings  and  walls.  With  this 
intention,  any  quantity  of  newly-made  po- 
t  atoe-starch  should  be  boiled  into  a  paste  ; 
a  sufficient  portion  of  which  ought  to  be 
mixed  with  the  whiteing,  after  the  latter 
has  been  diluted  with  water.  The  coat 
thus  prepared  is  much  clearer ;  retains  its 
whiteness  longer;  and  is  less  liable  to 
crack  or  scale,  than  such  as  is  mixed  with 
animal  glue....There  is  another  economi- 
cal way  of  employing  the  water  express- 
ed from  potatoes  in  the  processes  of  mak- 
ing starch  or  size.  This  liquor  is  useful 
for  washing  linen,  whether  plain  or  co- 
loured, silk  handkerchiefs,  stockings,  &c. 
without  the  aid  of  any  ley  or  soap  :  it  is 
said  to  improve  rather  than  to  diminish 
VOL.  If. 


the  tint,  while  it  restores  their  original 
brightness,  and  imparts  a  degree  of  stiff- 
ness to  silk  stuffs,  which  cannot  be  ob- 
tained by  the  common  method  of  clean- 
ing them.  It  deserves,  however,  to  be 
remarked,  that  no  discoloured  or  other- 
wise damaged  roots  must  be  used  for  this 
purpose. ...iiakers  convert  the  pulp  of  po- 
tatoes into  yeast,  by  adding  a  small  pro- 
portion (about  the  8th  or  10th  part)  of  the 
latter,  together  with  two  drachms  of  cal- 
cined and  pulverized  crabs'-claws  or  oy- 
ster-shells, and  a  similar  quantity  of  burnt 
hartshorn,  to  every  pailful  of  the  prepa- 
ration. This  compound  is  asserted  to  in- 
crease the  bulk  of  the  paste,  and  conse- 
quently of  the  bread;  but  double  the 
measure  of  it  is  required  to  serve  as  a 
complete  substitute  for  barm. 

Farther,  the  stalks  of  these  roots,  when 
cut  in  small  pieces,  afford  a  grateful  food 
to  cattle :  the  haulm  has  also  been  con- 
verted into  paper;  but  it  is  more  gene- 
rally, and,  we  conceive,  more  profitably, 
employed  for  stable-litter ;  or,  when  straw 
is  scarce,  instead  of  thatch  for  cottages.... 
Lastly,  even  the  potatoes  may  be  usefully 
employed  in  domestic  economy.  In  the 
New  Swedish  Journal  of  Agriculture  for 
1796,  it  is  directed,  that  such  potatoes 
should  be  collected  while  in  a  green  and 
hard  state  ;  then  well  rinsed  in  cold  wa- 
ter, and  put  for  48  hours  into  a  strong  fil- 
trated brine.  Next,  they  are  to  be  placed 
for  six  or  eight  hours  in  a  colander  or 
drain,  when  they  ought  to  be  boiled  in 
good  vinegar,  with  the  addition  of  some 
spice,  till  they  acquire  a  certain  degree  of 
transparency,  without  becoming  soft. 
Thus  prepared,  they  will  afford  a  more 
palatable  and  less  hurtful  pickle  than  ei- 
ther olives  or  cucumbers. 

The  potatoe  is  one  of  the  most  valua- 
ble roots  for  culinary  uses  :  when  boiled, 
it  forms  a  principal  article  of  food,  and 
serves  partly  as  a  substitute  for  bread. 
Mixed  with  wheaten  flour,  fermented 
with  yeast,  and  properly  baked,  it  makes 
a  wholesome  and  nutritious  loaf:  the  most 
economical  method  of  preparing  these 
roots,  we  have  already  stated. 

M.  Baume,  of  France,  has  invented  a 
very  convenient  machine  for  the  purpose 
of  grinding  potatoes  to  make  starch,  or  to 
obtain  flour  from  them  ;  a  plate  of  which, 
may  be  seen  in  the  Repertory  of  Jlrts,  or 
in  the  volume  on  potatoes,  published  by 
the  British  Board  of  Agriculture.  To 
those  who  wish  to  pursue  the  grinding  po- 
tatoes as  a  business,  the  machine  will  be 
found  highly  advantageous.  For  domes- 
tic purposes,  a  large  grater  will  be  suffi- 
cient. 

o  o 


POT 


POT 


Me.  Biddis  obtained  a  patent  from  the 
United  States  for  the  manufacture  of  po- 
tatoe  starch. 

POTTER'S  LEAD  ORE.    See  Lead. 

POTTERY.— The  art  of  making  potte- 
ry is  intimately  connected  with  chemistry, 
not  only  from  the  greatuse  made  of  earth- 
en vessels  by  chemists,  but  also  because 
all  the  processes  of  this  art,  and  the 
means  of  perfecting  it,  are  dependent  on 
chemistry.  We  must  however  acknow- 
ledge, that,  although  chemists  have  the 
greatest  interest  to  procure  good  cruci- 
bles and  other  earthen  vessels,  this  art 
lias  been  left  almost  entirely  to  the  potter. 
Mr.  Pott  is  the  first  who  attended  to  this 
object.  Beside  many  experiments  stated 
in  his  Lithogeognosia,  from  which  much 
instruction  may  be  received  relating  to 
the  perfection  of  chemical  vessels,  he  has 
written  a  treatise  expressly  on  this  sub- 
ject, in  which  he  gives  many  compositions 
for  crucibles,  the  chief  of  which  shall  be 
mentioned  in  this  article. 

All  kinds  of  pottery  are  in  general  made 
of  clays  or  argillaceous  earths,  because 
these  earths  are  capable  of  being  knead- 
ed, and  easily  receiving  any  form,  and  of 
acquiring  much  solidity  and  hardness  by 
exposure  to  fire.  But  clays  differ  much 
in  the  effects  produced  upon  them  by  fire. 
Some  clays  which  are  of  the  purest  kind 
resist  the  most  violent  fire  without  re- 
ceiving any  other  change  than  a  consider- 
able hardness;  but  still  they  are  not  ren- 
dered so  hard  and  compact  as  other 
clays.  A  second  kind  of  clays  by  expo- 
sure to  violent  heat  acquires  a  hardness 
equal  to  that  of  flints,  and  a  texture  com- 
pact and  glossy,  like  that  of  good  porce- 
lain ;  but  they  are  nevertheless  infusible 
by  the  most  violent  heat.  These  quali- 
ties are  occasioned  by  some  fusible  mate- 
vials  being  mixed  with  them,  as  sand, 
chalk,  gypsum,  or  ferruginous  earth, 
which  are  in  too  small  a  quantity  to  effect 
a  complete,  but  only  a  beginning  or  par- 
tial fusion.  Lastly,  a  tliird  kind  of  clays 
is  first  hardened  by  fire,  and  afterward 
completely  fused.  This  last  kind  of  clays 
evidently  contains  the  largest  quantity  of 
the  fusible  matters  above  mentioned. 

From  the  properties  of  these  three  prin- 
cipal clays  it  may  be  concluded,  that  from 
clays  alone  three  principal  kinds  of  potte- 
ry may  be  produced.  With  the  first  kind 
of  clay,  pots  or  crucibles  may  be  formed 
capable  of  sustaining  the  most  violent  fire 
without  fusion,  of  containing  melted  me- 
tals, and  even  hard  glasses  not  too  fluid  ; 
but  which,  from  want  of  sufficient  com- 
pactness, are  incapable  of  containing  dur- 
ing a  long  time  in  fusion  very  fusible  sub- 
stances, such  as  nitre,  glass  of  lead, 


glasses  containing  much  arsenic",  &.c.  by 
which  substances  their  pores  are  pervad- 
ed. These  clays  are  employed  advanta- 
geously for  the  formation  of  large  pots  or 
crucibles  used  in  glass-houses,  and  for  con- 
taining hard  glass,  as  bottle-glass,  &c. 

With  clays  of  the  second  kind  may  be. 
made  crucibles  and  other  potteries,  com- 
monly called  stone  ware.  Potteries  made 
with  these  earths,  when  sufficiently  bak- 
ed, are  very  sonorous,  so  hard  as  to  strike 
fire  with  steel,  capable  of  containing  all 
liquids,  of  which  the  former  kind,  from 
their  porosity,  are  incapable,  and  even  re- 
sist the  action  of  nitre,  glass  of  lead,  and 
other  fluxes,  when  the  earth  of  which 
they  are  formed  is  of  good  quality  :  but 
their  hardness  and  density,  which  pre- 
vent their  sudden  expansion  and  contrac- 
tion, by  the  hasty  application  of  heat  and 
cold,  make  them  liable  to  break  in  all  ope- 
rations where  they  are  suddenly  exposed 
to  heat  or  to  cold,  as  for  instance,  in  a  fur- 
nace through  which  a  strong  current  of 
air  passes.  If  this  kind  of  pottery  had 
not  this  inconvenience,  it  would  be  the 
best  and  most  perfect  for  the  purposes  of 
ordinary  life  and  chemistry.  Notwith- 
standing this  inconvenience,  it  is  the  only 
pottery  that  is  applicable  on  many  occa- 
sions; but  then  all  possible  care  must  be 
taken  to  prevent  its  breaking,  by  a  very 
gradual  application  of  heat  and  cold,  and 
by  protecting  it  from  currents  of  cold 
air. 

With  the  fusible  clays  may  be  made 
many  kinds  of  vessels,  which  are  cheap, 
as  they  require  little  fire  to  bake  them  ; 
for  all  this  kind  of  pottery  is  but  slightly- 
baked;  whence  its  texture  is  coarse  and 
porous.  Some  utensils  are  made  of  this 
pottery  without  glazing ;  but  in  general 
they  are  covered  with  a  glazing,  without 
which,  water  or  other  liquids  would  pass 
through  their  pores.  Some  of  this  potte- 
ry, which  is  finished  with  more  care,  is  co- 
vered with  a  white  enamel,  which  makes 
it  very  neat  and  like  porcelain.  This  is 
called  Delft  Ware.  This  is  a  kind  of 
pottery  made  at  Delft,  in  Holland,  which 
formerly  supplied  all  Europe,  until  it  was 
supplanted  by  a  yellow  pottery  made  in 
France,  which  has  since  given  place  to  the 
queen's  ware,  and  various  kinds  of  china 
fabricated,  in  Great  Britain. 

Pottery  may  be  distinguished  into  two 
kinds  ;  namely,  that  which  has  a  transpa- 
rent varnish  or  glaze,  and  that  which  has 
an  opake  glaze.  The  queen's  ware,  the 
stone  ware,  and  various  kinds  of  china, 
are  of  the  former  sort.  The  Delft  ware 
and  other  kinds  of  china  ware  are  of  the 
latter  kind.  In  every  kind  of  pottery  it  is 
an  object  of  great  importance,  that  the 


POT 


POT 


expansions  and  contractions  of  the  glaze 
and  the  body  should  be  nearly  the  same 
at  like  temperatures :  but  this  desirable 
property  is  seldom  found  in  vessels  cover- 
ed with  an  opake  glaze  or  enamel. 

As  the  Delft  pottery  has  fallen  into  dis- 
use, it  seems  of  less  consequence  to  in- 
quire into  its  composition,  more  especial- 
ly as  this  disuse  has  been  occasioned  by 
the  production  of  better  potteries.  Other 
coarser  potteries  of  this  kind  are  glazed 
with  glass  of  lead  mixed  with  metallic 
oxides,  or  fusible  coloured  earths ;  from 
whic  h  they  receive  various  colours.  This 
is  the  ordinary  pottery. 

A  fine  kind  of  pottery  is  made  of  white 
clays,  or  of  such  as  whiten  in  the  fire,  the 
surface  of  which  is  vitrified  by  throwing 
into  the  furnace,  when  the  ware  is  suffi- 
ciently baked,  some  common  salt  and  salt- 
petre. This  pottery  is  called  English 
ware  on  the  continent,  because  the  first 
and  best  was  made  in  England.  It  is 
white,  fine,  well  baked,  and  has  some 
small  degree  of  transparency  when  thin ; 
so  that  it  is  intermediate  betwixt  porce- 
lain and  common  stone-ware,  and  may 
therefore  be  called  a  semiporcelain. 

Keir  affirms,  that  he  has  never  seen  any 
English  stone-ware,  that  had  the  semi- 
transparency  and  whiteness,  mentioned 
by  Macquer.  As  the  English  stone-ware 
is  composed  of  tobacco-pipe  clay,  and 
ground  flints,  both  which  substances  are 
perfectly  infusible,  singly  or  jointly,  it  can- 
not possess  any  degree  of  transparency. 
The  use  of  the  flints,  is  to  give  strength 
to  the  ware,  so  as  it  shall  preserve  its 
form,  during  the  baking :  whereas  ves- 
sels made  of  clay  alone,  though  infusible 
by  fire,  and  capable  of  acquiring,  by  hav- 
ing been  exposed  to  an  intense  heat,  the 
hardness  of  the  best  porcelain  :  yet  while 
they  are  hot  and  soft,  they  sink  by  their 
own  weight,  so  as  to  lose  the  form  given 
them.  The  process  of  manufacturing 
this  stone-ware,  according  to  Dr.  Wat- 
son, is  as  follows  : 

Tobacco-pipe  clay  from  Dorcetshire, 
England,  is  beaten  much  in  water  :  by  this 
process,  the  finer  parts  of  the  clay  remain 
suspended  in  the  water,  while  the  coarser 
sand  andotherimpurities,fallto  the  bottom 
The  thick  liquid,  consisting  of  water  and 
the  finer  parts  of  the  clay,  is  farther  puri- 
fied, by  passing  it  through  hair  and  lawn 
sieves,  of  different  degrees  of  fineness. 
After  this,  the  liquid  is  mixed  (in  various 
proportions  for  various  wares)  with  ano- 
ther liquor,  of  as  nearly,  as  may  be  the 
same  density,  and  consisting  of  flints  cal- 
cined, ground  and  suspended  in  water. 
The  mixture  is  then  dried  in  a  kiln  ;  and 
bein£  afterwards  beaten  to  a  proper  tem- 


per, it  becomes  fit  for  being  formed  at 
the  wheel  into  dishes,  plutes,  bowls,  &c. 
When  the  ware  is  to  be  put  into  the  fur- 
nace to  be  baked,  the  several  pieces  of  it 
are  placed  in  the  cases  made  of  clay,  call- 
ed seggars,  which  are  piled  one  upon  ano- 
ther, in  the  dome  of  the  furnace  :  a  fire 
is  then  lighted ;  and  when  the  ware  is 
brought  to  a  temper,  which  happens  in 
about  48  hours,  it  is  glazed  by  common 
salt.  The  salt  is  thrown  into  the  furnace, 
through  holes  in  the  upper  part  of  it,  by 
the  heat  of  which  it  is  instantly  converted 
into  a  thick  vapour ;  which  circulating 
through  the  furnace,  enters  the  seggar 
through  holes  made  in  its  side  (tke  top 
being  covered,  to  prevent  the  salt  from 
falling  on  the  ware,)  and  attaching  itself 
to  the  surface  of  the  ware,  it  forms  that 
vitreous  coat  upon  the  surface,  which  is 
called  its  glaze. 

This  curious  method  of  glazing  earthen 
ware,  by  the  vapour  of  common  salt  was 
introduced  into  England  by  two  Dutch- 
men, near  a  century  ago.  It  appears  to  be 
produced  by  a  combination  of  the  alkali, 
with  the  siliceous  earth  or  sand  of  the 
clay. . 

The  yellow  or  queen's  ware,  is  made  of 
the  same  materials  as  the  flint-ware ;  but 
the  proportion  in  which  the  materials  are 
mixed  is  not  the  same,  nor  is  the  ware 
glazed  in  the  same  way.  The  flint-ware 
is  generally  made  of  four  measures  of  li- 
quid flint,  and  of  eighteen  of  liquid  clay ; 
the  yellow  ware  has  a  greater  proportion 
of  clay  in  it ;  in  some  manufactories  they 
mix  twenty,  and  in  others,  twenty-four 
measures  of  clay  with  four  of  flint.  These 
proportions,  if  estimated  by  the  weight  of 
the  materials,  would  probably  give  for  the 
flint-ware  about  three  cwt.  of  clay  to  one 
cwt.  of  flint,  and  for  the  yellow  ware  some- 
what more  clay.  The  proportion,  how- 
ever, for  both  sorts  of  ware  depends  very- 
much  upon  the  nature  of  the  clay,  which 
is  very  variable  even  in  the  same  pit. 
Hence  a  previous  trial  must  be  made  of 
the  quality  of  the  clay,  by  burning  a  kiln 
of  the  ware.  If  there  be  too  much  flint 
mixed  with  the  clay,  the  ware,  when  ex- 
posed to  the  air  after  burning,  is  apt  to 
crack  ;  and  if  there  be  too  little,  the  ware 
will  not  receive  the  proper  glaze,  from 
the  circulation  of  the  salt  vapour. 

This  glaze,  even  when  it  is  most  per« 
feet,  is  in  appearance  less  beautiful,  than 
the  glaze  on  the  yellow  ware. 

The  yellow  glaze  is  made,  by  mixing 
together  in  water,  till  it  becomes  as  thick 
as  cream,  1121b.  of  white  lead,  241b.  of 
ground  flint,and  6  lb.  of  ground  flint  glass, 
and  mix  only  801b.  of  white  lead  with 
20  lb.  of  ground  flint ;  and  others,  doubt* 


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less  observe  different  rules,  of  which  it  is 
very  difficult  to  obtain  an  account. 

The  ware  before  it  is  glazed,  is  baked, 
in  the  lire  :  by  this  means  it  acquires  the 
property  of  strongly  imbibing  moisture  ; 
it  is  therefore  dipped  in  the  liquid  glaze, 
and  suddenly  taken  out ;  the  glaze  is  im- 
bibed into  its  pores,  and  the  ware  pre- 
sently becomes  dry.  It  is  then  exposed  a 
second  time  to  the  fire,  by  which  means 
the  glaze  that  it  has  imbibed  is  melted, 
and  a  thin  glassy  coat  is  formed  upon  its 
surface  :  the  colour  of  this  coat,  is  more 
or  less  yellow,  according  as  a  greater  or 
less  proportion  of  lead  has  been  used. 
The  lead  is  principally  instrumental  in 
producing  the  glaze,  as  well  as  in  giving 
it  the  yellow  colour  ;  for  lead,  of  all  the 
substances  hitherto  known,  has  the  great- 
est power  of  promoting  the  vitrification 
of  the  substances,  with  which  it  is  mixed. 
The  flint  serves  to  give  a  consistence  to 
the  lead,  during  the  time  of  its  vitrifica- 
tion, and  to  hinder  it  f  rom  becoming  too 
fluid,  and  running  down  the  sides  of  the 
ware,  and  thereby  leaving  them  tinglaz- 
ed. 

The  yellowish  colour  which  lead  gives 
when  vitrified  with  flints,  may  be  wholly 
changed  by  very  small  additions,  of  other 
mineral  substances.  Thus,  to  give  one 
instance  ;  the  beautiful  black  glaze,  which 
is  fixed  on  one  sort  of  the  ware,  made  at 
Nottingham,  is  composed  of  twenty-one 
parts,  by  weight  of  white  lead,  of  five  of 
powdered  flints,  and  of  three  of  manga- 
nese. The  queen's  ware  at  present  made, 
is  much  whiter  than  formerly. 

The  coarse  stone-ware  made  at  Bristol, 
consists  of  tobacco  pipe  clay  and  sand, 
and  is  glazed  by  the  vapour  of  salt,  like 
Staffordshire  flint-ware  ;  but  it  is  far  in- 
ferior to  it  in  beauty. 

Chaptal  tried  various  methods  to  glaze 
pottery  without  lead,  and  two  among  them 
succeeded,  well  enough  in  his  opinion,  to 
justify  his  publishing  them.  The  first, 
consists  in  mixing  the  earth  of  Murviel, 
which  appears  to  be  a  fusible  or  com- 
pound clay,  in  water,  and  dipping  the  pot- 
tery therein :  this  done  it  is  suffered  to 
dry  ;  after  which  it  is  plunged  into  a  se- 
coud  water,  in  which  levigated  green  glass 
is  mixed.  This  covering  of  vitreous  pow- 
der fuses  with  the  clay  of  Murveil,  and 
the  result  is  very  smooth,  very  white,  and 
very  cheap  glazing. 

The  second  method  consists  in  immers- 
ing the  dried  pottery,  into  a  strong  solu- 
tion of  scasalt,  and  afterwards  baking  it. 
The  trial  which  Chaptal  made  in  his  fur- 
naces gave  him  reason  to  expect,  that  this 
method  might  be  used  in  large  works. 

He  likewise  obtained  a  very  black  glaz- 


ing, by  exposing  pottery,  strongly  heated 
to  the  fumes  of  sea-coal.  He  coated  se* 
veral  vessels  in  this  manner,  by  throwing 
a  large  quantity  of  coal  in  powder  into  a 
furnace,  wherein  the  pottery  was  ignited 
to  whiteness.  The  effect,  he  informs  us, 
is  still  more  complete,  when  the  chimneys 
or  tubes,  of  aspiration  of  the  furnace  are 
at  that  moment  closed,  and  kept  so  for 
some  minutes. 

The  residuum  left  after  distilling  oxy- 
genized muriatic  acid,  ground  with  sand, 
would  make  a  good  dark-bronze-coloured 
glaze,  free  from  the  noxious  qualities  im- 
putable to  lead. 

Mr.  Jousselin,  a  French  potter,  says, 
that  he  employs  a  glaze,  composed  en- 
tirely of  earthy  materials,  which  does  not 
cost  more  than  one-fifteenth  of  the  price, 
of  what  is  commonly  used.  And  the  pu- 
mice-stone affords  a  glaze,  that  contains 
nothing  in  the  least  noxious,  and  on 
which  no  menstruum  known,  has  the  least 
effect. 

A  writer  in  Sonnini's  Bibliotheque  Phy- 
sico  economique  observes,  that  it  is  of 
some  importance  in  domestic  economy,  to 
be  able  tojudge  of  the  goodness  of  an  ar- 
ticle in  such  extensive  use  as  earthen 
ware,  with  regard  to  the  goodness  and 
innoxiousness  of  its  coating. 

The  glaze  of  earthen  w  are,  may  have 
several  defects  :  it  may  be  scratched  more 
or  less  readily  by  a  hard  body  ;  weak 
acids,  sv.ch  as  vinegar,  lemon-juice,  ver- 
juice, &c,  may  attack  and  dissolve  the 
lead  it  contains  ;  or  oily  substances  stand- 
ing  long  on  it,  may  produce  the  same  ef- 
fect, stain  it  and  render  it  dull. 

To  determine  its  power  of  resisting 
friction,  it  may  be  rubbed  with  sand ;  and 
if  this  scratch  it  more  readily  than  it  does 
a  glaze,  known  to  be  good,  we  may  be  as- 
sured it  is  soft. 

If  vinegar  be  boiled  for  some  hours,  in 
a  vessel  coated  with  a  soft  glaze,  it  will 
attack  the  glaze,  and  dissolve  a  portion  01 
its  lead,  which  will  be  precipitated  from 
die  vinegar,  on  the  addition  of  a  few  drops 
of  sulphuric  acid,  commonly  called  oil  of 
vitriol. 

But  a  method  more  within  every  one's 
reach,  and  therefore  deserving  to  be 
known,  is  to  let  fall  a  drop  of  strong  ink,on 
a  piece  of  earthen  ware,  dry  it  before  the 
fire,  and  then  wash  it.  If  the  glaze  be 
too  soft,  the  ink  will  leave  on  it  a  slight 
spot. 

Some  potteries  can  sustain  a  sudden 
application  of  heat  and  cold,  sufficiently 
well  for  the  uses  of  the  kitchen,  and  are 
always  the  coarsest,  least  baked,  and  the 
glazing  of  which  is  the  softest.  They 
also  do  not  last  long,  when  much  used  ; 


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POT 


for  it  is  absurd  to  suppose,  as  some  per- 
sons do,  that  pottery  may  be  made  capa- 
ble of  sustaining1  fire  like  a  metal  vessel. 
We  are  certain,  that  the  best  of  this  kind, 
which  are  employed  for  this  purpose, 
break  as  soon  as  they  are  put  upon  the 
fire.  They  do  not  indeed  break  so  as  to 
separate  in  pieces,  or  even  to  let  liquors 
pass  through  them  :  but  many  Mosul 
cracks  which  may  be  perceived  in  their 
glazing,  and  by  their  ceasing  to  ring  when 
struck,  after  they  have  been  once  heated. 
Each  time  that  these  vessels  are  set  on 
the  fire,  many  small  and  imperceptible 
cracks  are  formed  in  them,  which  by  fre- 
quent use,  become  so  numerous,  that  the 
vessel  may  be  broken  by  the  least  force. 
Thus  all  the  difference  betwixt  the  pot-, 
teries,  which  are  intended  to  be  used  on 
the  fire,  and  the  good  stone-ware  which 
is  not  intended  for  that  purpose,  is,  that 
the  latter  kind  may  be  broken  at  once, 
when  heated  and  cooled  carelessly,  where- 
as the  former  is  broken  by  degrees.  Ne- 
vertheless the  fire-ware  is  useful,  as  it  can 
serve  for  a  short  time. 

Tobacco-pipes  require  a  very  fine,  te- 
nacious, and  refractory  clay,  which  is  ei- 
ther naturally  of  a  perfectly  white  colour, 
or,  if  it  had  somewhat  of  a  gray  cast,  will 
necessartly  burn  white.  A  clay  of  this 
kind,  must  absolutely  contain  no  calcare- 
ous or  ferruginous  earth,  and  must  like- 
wise be  carefully  deprived  of  any  sand,  it 
may  contain  by  washing.  It  ought  to  pos- 
sess, besides,  the  capital  property  shrink- 
ing but  little  in  the  fire.  If  it  should  not 
prove  sufficiently  ductile,  it  may  be  melio- 
rated, by  the  admixture  of  another  sort, 
hast  of  all,  it  is  beaten,  kneaded,  ground, 
washed,  and  sifted,  till  it  acquires  the 
requisite  degree  of  fineness  and  ducti- 
lity. 

When  after  this  preparation,  the  clay 
has  obtained  a  due  degree  of  ductility,  it 
is  rolled  out  in  small  portions,  to  the  usual 
length  of  a  pipe,  perforated  with  a  wire, 
and  put  together  with  the  wire,into  a  brass 
mould,  rubbed  over  with  oil,  to  give  it  its 
external  form  ;  after  which  it  is  fixed  in  a 
vice,  and  the  hollow  part  of  the  head 
formed  with  a  stopper.  The  pipes  thus 
brought  into  form,  are  cleared  of  the  re- 
dundant clay  that  adheres  to  the  seams, 
they  are  then  marked  with  an  iron  stamp 
upon  the  heel,  and  their  surfaces  smooth- 
ed and  polished.  When  they  are  well 
dried,  they  are  put  into  boxes,  and  baked 
in  a  furnace. 

In  the  Dutch  manufactories,  these  box- 
es consist  of  conical  pots  made  of  clay, 
with  conical  lids,  with  a  tube  passing 
through  the  middle  of  them,  by  which  the 
pipes  are  supported ;  or  else  they  are 


long  clay  boxes,  in  which  the  pipes  ar<». 
laid  horizontally,  and  stratified  with  frag- 
ments of  pipes  pounded  small. 

Lastly,  the  pipes  when  baked,  should 
be  covered  with  a  glazing  or  varnish,  and 
afterwards  rubbed  with  a  cloth.  This' 
glazing  consists  of  a  quarter  of  a  pound 
of  soap,  two  ounces  of  white  wax,  and  one 
ounce  of  gum  arabic  or  tragacanth,  which 
are  all  boiled  together,  in  five  pints  of  wa- 
ter for  the  space  of  a  tew  minutes. 

Under  the  article  Glass,  we  have  treat- 
ed on  the  fusibility  of  earthy  mixtures,  to 
which  therefore  we  shall  refer  our  read- 
ers. Porcelain  may  be  defined  to  be  a 
species  of  pottery  ware  composed  of  an 
earthy  mixture  which  resists  complete 
fusion  in  a  very  considerable  heat,  but  has 
been  brought  by  a  less  heat  than  its  melt- 
ing point  to  a  state  of  incipient  fusion,  and 
thereby  acquired  extreme  hardness,  sono- 
rousness, semitransparency,  and  a  semi- 
conchoidal  splintery  fracture,  approach- 
ing- to  the  vitreous  which  is  completely 
conchoidal.  This  last  is  quite  a  distinc- 
tive character  between  porcelain  and  pot- 
tery, for  the  fracture  of  the  latter  is  sim- 
ply  granular.  It  appears  probable,  there- 
fore, that  no  chemical  action  takes  place 
in  any  pottery  mixture  till  it  arrives  at  the 
state  of  porcelain.  The  most  perfect  and 
beautiful  porcelains  of  Japan  and  China 
are  composed  (as  appears  from  the  best 
testimony)  of  one  earth  in  which  silex 
predominates,  and  which  melts  in  a 
strong  fire,  and  of  another  which  is  infu- 
sible per  se,  and  by  an  union  of  these 
alone  (as  it  appears)  a  porcelain  is  por- 
duced  which  scarcely  vitrifies  at  the  ut- 
most furnace  heat  which  art  can  produce. 
This  substance  has  the  united  excellen- 
cies of  being  very  hard,  of  a  beautiful  se- 
mi-transparence, very  white  where  not  ar- 
tificially coloured,  very  tough  and  cohe- 
sive, so  that  it  has  strength  enough  for 
the  purposes  for  which  it  is  designed 
when  made  very  thin,  and  it  bears  sud- 
den heating  and  cooling  without  crack- 
ing. 

Of  the  beautiful  European  porcelains 
which  have  been  made  in  imitation  of  the 
oriental,  it  should  seem  that  none  of  them 
precisely  unites  all  its  distinguishing  qua- 
lities. Earthy  mixtures  have  been  made 
equally  strong,  tough,  and  infusible,  and 
as  truly  porcellanous  when  burnt,  but 
these  have  not  exactly  equalled  the  best 
Japanese,  in  delicate  whiteness  and  lustre. 
But  as  the  latter  are  the  most  essential 
qualities,  that  of  infusibility  has  been  in 
general  sacrificed,  (which  indeed  is  of  no 
consequence  for  any  of  the  common  uses 
of  porcelain)  and  therefore  those  that 
come  up  to  the  oriental  in  beauty  and  do- 


POT 

licacy,  of  which  there  are  several  manu- 
factures in  different  parts  of  Europe,  for 
the  most  part  soften  and  melt  down  in 
the  most  intense  heat  of  a  wind-furnace, 
at  which  the  true  Nankin  and  Japanese 
undergo  no  change. 

Porcelain,  if  not  properly  annealed,  is 
extremely  brittle,  and  liable  to  crack  :  to 
prevent  such  accidents,  it  ought  to  be 
well  boiled  in  pure  water,  before  it  is 
used ;  and,  when  cold,  no  hot  fluid  should 
be  put  into  it,  unless  there  be  some  sugar, 
or  a  tea-spoon  in  the  vessel.  Another  me- 
thod of  obviating  casualties,  is  that  of 
holding  china-vessels  over  steam,  immedi- 
ately before  tea  or  coffee  is  poured  into 
them.  Accidents,  however,  often  deface 
the  beauty,  or  otherwise  diminish  the 
value  of  a  set  of  china  :  hence,  it  be- 
comes a  desirable  object  to  join  or  ce- 
ment the  fragments,  so  as  to  be  imper- 
ceptible to  the  naked  eye.  Under  the  ar- 
ticle Cement,  we  have  stated  the  most 
propef  expedients  for  this  purpose. 

The  manufacture  of  the  ordinary  pot- 
tery is  on  the  whole  very  simple,  where 
:he  due  selection  of  materials  is  made, 
but  it  is  the  more  delicate  ornamental 
part,  the  modelling,  enamelling,  painting', 
gilding,  &c.  which  displays  so  much  ex- 
quisite beauty,  and  which  requires  a  com- 
bination of  perseverance,  skill,  and  prac- 
tical nicety  of  management,  that  is  hard- 
ly equalled  in  any  other  chemical  manu- 
facture. 

The  intimate  mixture  of  the  ingredi- 
ents used  in  pottery,  is  of  great  impor- 
tance to  the  beauty,  compactness,  and 
soundness  of  the  ware.  Formerly  the 
wet  clay  and  ground  flint  (or  whatever 
was  the  other  material)  were  beaten  toge- 
ther with  great  and  long-continued  ma- 
nual labour,  no  more  water  being  added 
than  was  necessary  to  render  the  clay 
thoroughly  plastic.  This  laborious  (and 
therefore  expensive)  method  has  now 
been  laid  aside  in  the  larger  potteries, 
and  the  ingenious  way  has  been  substi- 
tuted of  bringing  each  material  first  to 
«B  impalpable  powder,  and  diffusing 
them  separately  in  as  much  water  as  will 
bring  them  to  the  consistence  of  thick 
cream,  mixing  them  in  due  proportion  by 
measure,  and  when  thoroughly  stirred  to- 
gether, evaporating  the  superfluous  wa- 
ter till  the  mass  is  brought  to  a  due  con- 
sistence for  working. 

The  following  is  the  common  process 
used  in  Staffordshire  for  making  the  ordi- 
nary ware.  The  materials  are  a  fine  clay 
brought  chiefly  from  Devonshire,  and  a 
iiiiceous  stone  called  Chert,  or  else  com- 
mon flint  reduced  to  powder  by  heating 

1  hot,  quenching  in  water,  and  then 


POT 

grinding  by  wind-mills  to  a  subtle  pow- 
der. Kach  material  is  passed  through 
fine  brass  sieves,  then  diffused  in  water, 
mixed  by  measure,  and  brought  to  a  plas- 
tic state  in  the  way  just  mentioned.  A 
lump  of  this  is  then  thrown  on  the  pot- 
ter's wheel,  and  by  the  workman's  hands 
assisted  by  a  small  blunt  iron  knife -blade 
it  is  fashioned  into  the  shape  required, 
when  circular,  such  as  cups,  saucers, 
plates,  Bee.  but  when  made  oval,  or  to  any 
pattern  form,  it  is  moulded  on  a  plaisteV 
model.  Handles  and  spouts  are  then 
st  uck  on,  if  required,  and  the  piece,  after 
being  again  smoothed  and  the  shape  movr 
accurately  touched  up,  is  set  to  dry  for 
some  days  in  a  warm  room,  where  it  be- 
comes so  hard  as  to  bear  handling  with- 
out altering  its  shape.  When  dry  enough, 
it  is  enclosed  along  with  many  others  in 
baked  clay  cases  of  the  shape  of  band- 
boxes, called  seggars,  which  are  made  of 
the  coarse  clays  of  the  country.  These 
are  next  ranged  in  the  kiln  or  furnace  so 
as  to  fill  it,  except  a  space  in  the  middle 
for  the  fuel.  Here  the  ware  is  baked  till 
it  has  remained  fully  red-hot  for  a  consi- 
derable time,  which  in  the  larger  kilns 
consumes  10  or  15  tons  of  coal,  after 
which  the  fire  is  allowed  to  go  out,  and 
when  all  is  cooled,  the  seggars  are  taken 
out  and  their  contents  unpacked.  The 
entire  contents  of  one  kiln  will  some- 
times exceed  30,000  different  pieces  of 
pottery.  The  ware  is  then  in  the  state  of 
biscuit it  is  perfect  pottery,  very  hard, 
beautifully  white  with  a  slight  shade  of 
yellow,  and  of  a  smooth  surface,  quite 
void  of  gloss,  much  resembling  a  clean 
egg-shell. 

The  next  process  is  the  glazing,  which 
is  performed  on  all  pottery  intended  for 
domestic  use.  For  this  purpose  the  bis- 
cuit ware  is  dipped  in  a  tub  containing  a 
mixture  of  about  60  parts  of  litharge,  10 
of  clay,  and  20  of  ground  flint,  diffused 
in  water  to  a  creamy  consistence,  and 
when  taken  out  enough  adheres  to  the 
piece  to  give  an  uniform  glazing  when 
again  heated.  The  pieces  are  then  again 
packed  up  in  the  seggars,  with  small  bits 
of  pottery  interposed  between  each,  and 
fixed  in  a  kiln  as  before.  The  glazing 
mixture  fuses  at  a  very  moderate  heat, 
and  gives  an  uniform  glossy  coating, 
which  finishes  the  process  when  it  is  in- 
tended for  the  common  white  ware.  But 
the  painting  and  gilding,  each,  require  se- 
parate processes. 

Something  may  be  added  in  this  place 
on  the  pottery  employed  in  chemical  ope- 
rations. Formerly,  when  chemists  made 
their  own  crucibles,  muffles,  &c.  this  was 
a  very  important  brach  of  practical  know- 


POT 


POT 


ledge  to  every  chemist,  but  at  present 
this  is  almost  wholly  confined  to  the  ma- 
nufacturer, and  we  are  only  able  to  point 
out  some  of  the  leading-  circumstances 
which  determine  the  goodness  of  pottery 
ware  for  one  or  other  purpose. 

Some  very  eminent  chemists,  among 
whom  we  may  enumerate  Glauber,  Agri- 
cola,  and  Pott,  have  paid  particular  atten- 
tion to  this  subject,  and  that  enlightened 
manufacturer,  the  lale  Mr.  Wedgewood, 
has  introduced  a  species  of  ware  which 
answers  some  important  purposes  better 
than  any  hitherto  invented. 

Three  important  requisites  arc  de- 
manded to  constitute  a  perfect  pottery  for 
all  chemical  purposes,  namely,  infusibili- 
ty  at  any  heat ;  compactness  of  texture 
so  as  to  retain  saline  and  other  fluxes  in 
fusion  without  being  materially  acted  on 
by  them,  or  allowing  them  to  transpire  ; 
and  endurance  of  sudden  changes  of  tem- 
perature, particularly  sudden  healing', 
without  cracking  or  giving  way  in  any  de- 
gree. 

These  three  requisites,  however,  have 
been  found  impracticable  to  be  united  in 
the  same  ware,  which  has  led  to  the  ne- 
cessity of  selecting  the  species  of  ware 
according  to  the  intended  use. 

It  is  of  considerable  importance  in  all 
fire -vessels,  that  they  should  be  able  to 
bear  heating  and  cooling  with  tolerable 
quickness,  but  it  unfortunately  happens 
that  some  of  the  most  perfect  ware  in  eve- 
ry oUier  respect,  is  very  deficient  in  this, 
and'vill  even  hardly  bear  the  draught 
and  flame  of  a  wind  furnace,  however 
slowly  heated,  without  danger  of  crack- 
ing. This  is  particularly  the  case  with 
the  valuable  porcelain  fire-ware  invented 
by  Mr.  Wedgewood.  This  property  of 
cracking  on  sudden  changes  of  tempera- 
ture, appears  particularly  to  depend  on 
the  two  circumstances  of  hardness  and 
closeness  of  texture,  and  the  latter  is  the 
greatest  (ceteris  paribus)  in  proportion  to 
the  fineness  of  division  of  the  materials 
before  burning.  Thus  in  the  ware  just 
mentioned,  both  the  clay  and  flint  are 
brought  to  a  most  impalpable  powder  be- 
fore mixture,  and  the  texture  is  uncom- 
monly hard  and  close  ;  and  on  the  other 
hand,  it  has  been  found  necessary  in  mak- 
ing the  best  Hessian  and  other  crucibles, 
to  separate  and  reject  the  finer  part  of  the 
siliceous  ingredient,  for  the  express  pur- 
pose of  enabling  it  to  bear  the  strong 
draught  of  the  wind  furnace.  The  Wedge- 
wood ware  stands  sudden  healing  and 
cooling  better  when  it  is  covered  with  a 
thin  coating  of  Windsor  loam,  or  of  a 
a  fire-lute  composed  of  cby  and  co*arse 
sand,  and  tow  or  horse-dung. 


Of  the  earthen  vessels  intended  to  hold 
acid  or  corrosive  liquors  in  distillation,  no 
ware  is  so  perfect  as  the  white  Wedge- 
wood porcelain  ware  already  mentioned, 
its  texture  being  so  close  as  not  to  re- 
quire any  lead-glazing.  The  only  defect 
of  this  is  the  danger  of  cracking  on  any 
sudden  change  of  temperature. 

All  the  operations  where  great  heat  is 
employed,  require  vessels  of  baked  earth  ; 
because  these  alone  can  sustain  at  once 
the  action  of  violent  fire  and  of  chemical 
solvents.  Vessels  made  of  good  baked 
clay  eminently  possess  these  two  quali- 
ties, and  are  the  best  which  can  be  em- 
ployed in  chemistry  ;  but  as  they  have  the 
ineonvenience  of  breaking  by  sudden  ap- 
pheation  of  heat  and  cold,  and  as  many 
operations  do  not  require  vessels  so  dense, 
mixtures  of  earth  have  been  used,  of 
which  crucibles  are  made,  capable  of 
being  rendered  suddenly  red  hot, and  sud- 
denly cooled  without  breaking,  and  suffi- 
ciently dense  to  contain  metals  and  other 
matters  in  fusion  during  a  long  time.  The 
best  crucibles  of  this  kind  are  brought 
from  Hesse  in  Germany.  These  crucibles 
are  made  with  a  good  refractory  clay, 
mixed,  according  to  Pott,  with  two  parts 
of  sand  of  a  middling  fineness,  from  which 
the  finest  part  has  been  sifted.  The  mix- 
ture of  sand  with  clay  produces  two  good 
effects  ;  the  first,  to  make  the  clay  leaner, 
as  it  is  called,  and  thus  to  prevent  the 
clay  from  cracking  by  the  contraction  it 
sustains  during  its  drying ;  and  secondly, 
to  prevent  its  acquiring  too  great  close- 
ness and  compactness  of  texture  by  being 
baked..  Thus  we  obtain  crucibles  mode- 
rately dense,  capable  of  containing  me- 
tals and  other  things  in  fusion,  and  infi- 
nitely less  subject  to  break  by  heat  and 
cold  than  those  made  of  pure  clay. 

The  particles  of  the  sand  mixed  with 
clay  in  this  composition  for  crucibles, 
ought  to  be  rather  of  a  moderate  size, 
than  very  fine  ;  because,  as  Pott  remarks, 
the  former  render  the  crucibles  much  less 
apt  to  crack  than  the  latter.  In  the  se- 
cond place,  that  chemist  forbids  the  use 
of  sand,  flints,  or  other  earths  of  that  kind, 
in  the  composition  of  crucibles  intended 
to  contain  glasses,  or  other  vitrifying  mat- 
ters, a  long  time  in  fusion  ;  because  these 
vitreous  matters  act  upon  sand,  flints,  and 
all  those  called  vitrifiable  earths,  by  which 
means  these  crucibles  are  soon  penetrated 
and  melted. 

This  inconvenience  is  prevented,  and 
all  the  advantages  obtained  from  a  mix 
ture  of  sand  are  procured,  by  substituting 
to  the  sand  a  good  baked  clay  in  gross 
powder.  In  this  manner  are  made  the 
pots  which  contain  the  vitrifiable  mate- 


POT 

/ 

rials  in  glas-house  furnaces,  some  of  which 
resist  the  continued  fires  employed  there 
during  three  weeks  or  a  month.  The  pots 
indeed  used  in  glass-houses  frequently 
sustain  a  constant  tire  during-  several 
months,  and  sometimes  even  a  vera-.  They 
become  gradually  more  and  more  thin, 
the  glass  or  flux  contained  probably  dis- 
solving them  thus  slowly. 

The  quantity  of  burnt  clay  in  the  com- 
position for  crucibles  varies  in  proportion 
to  the  nature  of  the  crude  clay  from  1,  2, 
2},  or  even  three  parts  of  the  former,  to 
one  of  the  latter.  In  general,  the  stronger, 
more  tenacious,  and  compact  the  crude 
clay  is,  the  larger  quantity  of  burnt  clay 
ought  to  be  mixed  with  it. 

The  crucibles  made  in  France  are  com- 
posed on  the  same  principles.  They  are 
made  of  clay,  mixed  with  broken  butter- 
pots,  which  are  a  stone-ware  made  in  Nor- 
mandy and  Picardy.  These  crucibles  re- 
sist admirably  well"  sudden  heat  and  cold, 
and  they  would  be  excellent  if  the  crude 
clay  which  enters  into  their  composition 
was  capable  of  resisting  a  violent  lire  ;  but 
this  clay  being  mixed  with  martial  and  py- 
ritous  matters  swells  in  the  fire,  and  be- 
gins to  melt.  Besides,  these  crucibles 
owe  their  good  quality  of  not  breaking  by 
sudden  application  of  heat  and  cold  to 
their  little  density,  which  is  attended  with 
this  inconvenience,  that  they  are  penetra- 
ble by  very  fluid  matters. 

We  may  from  what  has  been  said  per- 
ceive the  difficulty,  perhaps  the  impossi- 
bility, of  making  perfect  crucibles.  Pott 
lias  made  so  many  experiments  on  this 
subject,  that  he  seems  to  have  exhausted 
it.  The  basis  of  all  his  compositions  was 
clay  ;  but  this  he  mixed  in  different  pro- 
portions with  metallic  oxides,  burnt  bones, 
calcareous  stones,  talcs,  amianthus,  asbes- 
tUSj  pumice-stones,  tripoU,  ami  many 
others,  from  none  of  which  did  he  obtain 
a  perfect  composition,  as  may  be  seen 
from  his  Dissertation :  hence  it  may  be 
concluded,  that  we  must  have  in  our  labo- 
ratories crucibles  of  different  kinds  suita- 
ble to  the  several  operations: 

Crucibles  may  possibly  be  made  better 
than  any  hitherto  known,  and  of  more  ex- 
tensive use.  The  essential  point  is  to  obtain 
a  very  refractory  clay  free  from  pyritous 
matter  and  ferruginous  earth,  from  which 
the  sand  must  be  washed.  This  must  be 
mixed  with  two  or  three  parts  of  the  same 
clay  baked  and  pounded  grossly ;  and  of 
this  mixture  or  paste,  crucibles  must  be 
formed  in  moulds,  and  baked  in  a  very 
strong  fire.  As  retorts  and  cucurbits  are 
designed  for  the  distillation-of  liquors  ge- 
nerally very  corrosive  and  penetrating, 


POT 

they  ought  to  be  made  of  stone-ware.  To 
this  the  following  observations  may  be 
added : 

1.  Crucibles  made  of  fat  clays  are  more 
apt  to  crack,  when  suddenly  exposed  to 
heat,  than  those  made  of  lean  or  meagre 
clays.  Meagre  clays  are  those  in  which  a 
considerable  quantity  of  sand  is  mixed 
with  the  pure  argillaceous  earth,  and  fat 
clays  are  those  w  hich  contain  but  a  small 
proportion  of  sand. 

2.  Some  crucibles  become  porous  by 
long  exposure  to  lire,  and  imbibe  part  of- 
the  contained  metals.  This  inconvenience 
is  prevented  by  glazing  the  internal  and 
external  surfaces,  which  may  be  done  by 
moistening  these  with  oil  of  tartar,  or  by 
strewing  upon  them,  when  wetted  with 
water,  powdered  glass  of  borax.  These 
glazings  are  not  capable  of  containing 
glass  of  lead. 

3.  Crucibles  made  of  burnt  clay  grossly 
powdered,  together  with  unburnt  clay, 
were  much  less  liable  to  crack  by  heat 
than  crucibles  macle  of  the  same  mate- 
rials, but  in  which  the  burnt  clay  w  as 
finely  powdered,  or  than  crucibles  made 
entirely  of  unburnt  clay. 

4.  If  the  quantity  of  unburnt  clay  be  too 
great,  the  crucibles  will  be  apt  to  crack 

-in  the  fire.  Crucibles  made  of  ten  ounces 
of  unburnt  cluy,  ten  ounces  of  grossly 
powdered  burnt  clay,  and  three  drachms 
of  calcined  sulphat  of  iron,  are  capable  of 
retaining  melted  metals,  but  are  pervaded 
by  glass  of  lead.  The  following  compo- 
sition is  as  good  or  better  than  the*pre- 
ceding: — Seven  ounces  of  unburnt  play* 
fourteen  ounces  of  grossly  powdered  burnt 
clay,  aud  one  drachm  of  calcined  su'iphat 
of  iron.  These  crucibles  may  be  render- 
ed more  capable  of  containing  glass  of 
lead,  by  lining  their  internal  surfaces,  be- 
fore they  are  baked,  with  burnt  clay  di- 
luted with  water.  They  may  be  farther 
strengthened  by  making  them  thicker  than 
is  usually  done,  or  by  covering  their  ex- 
ternal surfaces  with  some  unburnt  clay, 
which  is  called  arming  them. 

5.  The  composition,  of  which  crucibles 
the  most  capable  of  containing  glass  of 
lead  were  made,  was  eighteen  parts  of 
gTossly  powdered  burnt  clay,  as  much 
unburnt  clay,  and  one  part  of  fusible  spar. 
These  crucibles  must  not,  however,  be 
exposed  too  suddenly  to  a  violent  heat. 

6.  Crucibles  capable  of  containing  very 
well  glass  of  lead,  were  made  of  twenty- 
four  parts  of  unburnt  clay,  four  parts  of 
burnt  clay,  and  one  part  of  chalk.  These 
require  to  be  armed. 

7.  Plume-alum  powdered,  and  mixed 
with*  whites  of  eggs  and  water,  being  ap- 


PRE 


PKI 


plied  to  the  internal  surface  of  a  Hessian 
crucible,  rendered  it  capable  of  containing1 
glass  of  lead  during  a  long  time. 

8  One  part  of  ciay,  and  two  parts  of 
Spanish  chalk, made  good  crucibles.  The 
substance  called  Spanish  chalk  is  not  a 
calcareous  earth,  but  appears  to  be  a  ste- 
atites. 

9.  Two  parts  of  Spanish  chalk,  and  one 
part  of  powdered  tobacco  pipes,  made  a 
good  composition  for  lining  common  cru- 
cibles. 

10.  Eight  parts  of  Spanish  chalk,  as 
much  burnt  clay,  and  one  part  of  litharge, 
made  solid  crucibles. 

11.  Crucibles  made  of  black  lead  are 
fitter  than  Hessian  crucibles  for  the  melt- 
ing of  metals;  but  they  are  so  porous, 
that  fused  salts  pass  entirely  through 
them.  They  are  more  tenacious  than 
Hessian  crucibles,  are  not  so  apt  to  burst 
in  pieces,  and  are  more  durable. 

12.  Crucibles  placed  with  their  bottoms 
upwards  are  less  apt  to  be  cracked  du- 
ring the  baking  than  when  placed  differ- 
ently. 

13  The  paste  of  which  crucibles  are 
made  ought  not  to  be  too  moist,  else  when 
dried  and  baked  they  will  not  be  suffi- 
ciently compact:  hence  they  ought  not 
to  be  so  moist  as  to  be  capable  of  being 
worked  on  a  potter's  lathe,  but  they  must 
be  formed  in  brass  or  wooden  moulds. 
See  Pott's  Dissertation  on  Chemical  Ves- 
sels. 

SchefFer  says,  that  the  best  crucibles 
cannot  easily  contain  metals  dissolved  by 
sulphur,  in  the  operation  of  parting  by 
means  of  sulphur.  See  Parting.  He 
says,  that  they  may  be  made  much  more 
durable  and  solid,  by  steeping  them  a  few 
days  in  linseed  oil,  and  strewing  powder- 
ed borax  upon  them  before  they  are  dried. 
JSkm.  Sutd.  xiv,  1752. 

POTSTONE  — A  mineral  of  a  greenish 
grey  colour,  generally  found  in  beds  with 
serpentine,  remarkably  soft.  It  may  be 
turned  into  vessels  of  various  shapes. 

POWDER,  Gun.    See  Gunpowder. 

POWER,  in  Mechanics.  See  Mecha- 
nics. 

PRESERVATION,  is  the  art  of  pre- 
serving animal  and  vegetable  substances 
from  putrefaction  or  decay.  On  several 
occasions,  we  mentioned  the  use  of  differ- 
ent simple  and  compound  bodies  which 
are,  or  may  be,  used  for  this  purpose. 
See  the  articles  Bacon,  Beef,  Cheese, 
Pickle,  Purification,  &c 

Pi:ESS,  Simmon's  Patent.  See  Me- 
chanics. 

PRESS,  Screw.    See  Mechanics. 

PRESS,  Watee.    See  Hydraulics. 

PRESS,  Pumice.  See  Pumice-press. 
VOL.  II. 


PRINCES  METAL.    See  CorpiR. 
PRINTERS,  or  PRINTING  INK.  See 
Ink. 

PRINTING,  is  the  art  of  taking  im- 
pressions from  types,  &c  This,  like  other 
arts  has  been  much  improved ;  the  con- 
struction of  presses,  the  formation  of 
types,  ink,  &c.  has  rendered  the  art  at 
present  more  perfect  than  in  the  earlier 
periods  of  the  discovery.  For  the  his- 
tory and  progress  of  printing,  we  refer 
the  reader  to  Thomas's  History  of  Print- 
ing, an  American  publication. 

It  may  not  be  thought  amiss  to  men- 
tion, however,  that  the  art,  according  to 
Wiilich,  is  divided  into  three  distinct 
branches;  namely,  1.  From  copper-plates, 
lor  pictures,  which  is  denominated  rolling' 
press  printing.  2.  From  blocks,  on  which 
birds,  flowers,  and  other  representations 
are  cut,  for  printing  linen,  cotton,  or  si- 
milar articles,  and  which  is  known  under 
the  name  of  calico-printing.  3.  From 
moveable  letters,  for  multiplying  books, 
and  which  has  received  the  appellation  of 
letter-press  printing. 

The  branch  last  mentioned,  is  undoubt- 
edly the  most  curious  and  valuable;  as  to 
its  general  dissemination,  may  be  chiefly 
attributed  the  progress  of  learning ;  the 
numberless  discoveries  and  improvements 
in  the  arts  and  science,  together  with  a 
variety  of  other  valuable  contrivances  in 
domestic  life,  that  must  otherwise  have 
been  confined  to  the  knowledge  of  a  few 
individuals,  if  not  totally  lost  to.  mankind. 
Hence,  several  cities  have  contended  for 
the  honour  of  its  first  introduction ;  but 
the  claim  is  confined  principally  to  Haar- 
lem, in  Holland  (where  it  was  invented  by 
Laurence  Coster),  and  to  Mentz,  in  Ger- 
many (where  Faust  and  Guttenberg  were 
the  first  printers)  :  to  each  of  these  it 
may  in  some  measure  be  ascribed;  the 
printing  with  separate  wooden  types  being 
first  practised  at  Haarlem  in  1430  ;  as  that 
with  metal  types  (which  were  first  cut, 
and  afterwards  cast)  was  discovered  at 
Mentz,  in  the  \  ear  1444,  or  1445. 

From  Holland,  the  art  of  printing  was 
introduced  into  England,  about  the  mid- 
dle of  the  15th  century :  it  was  first  car- 
ried on  at  Oxford ;  whence  it  has  been 
diffused  to  every  quarter  of  the  island, 
and  is  now  brought  near  to  the  acme  of 
perfection. 

In  the  year  1/95,  the  Society  for  the  En- 
couragement of  Arts,  &c.  conferred  a 
bounty  of  40  guineas  on  Mr.  Ridley,  for 
his  invention  of  a  printing  press,  on  a  new 
construction  ;  but,  as  a  description  of  its 
mechanism  would  be  intelligible  only  to 
printers,  the  reader  is  referred  to  the  13th 
volume  of  the  Society's  *  Transactions/' 
r  p 


PRI 


PRI 


where  it  is  accurately  described,  and  il- 
lustrated with  an  engraving. 

Mr.  Fessenden,  in  his  Register  of  Arts, 
observes,  that  "  in  the  art  of  printing,  an 
important  improvement  invented  by  Mr. 
Hugh  Maxwell,  has  been  made  and  in 
practical  use  in  three  printing  offices  of 
Philadelphia.  The  improvement  consists 
of  a  roller  used  for  inking  the  type.  The 
advantages  of  which  are  greater  regula- 
rity in  the  distribution  of  the  ink,  a  per- 
fect equality  of  colour,  with  a  trifling  at- 
tention, a  considerable  saving  in  the  ex- 
pense of  printing,  and  a  cleanliness,  as 
respects  picks,  monks,  and  friars,  not  to 
be  attained  by  the  utmost  care  with  the 
common  balls.  Another  advantage  which 
will  be  felt  by  every  printer  who  adopts 
this  plan,  the  accident  of  drawing  letters 
so  destructive  to  printing  type,  so  inju- 
rious to  part  of  the  machinery  of  the 
press,  and  frequently  productive  of  gross 
errors,  is  totally  avoided. 

The  machine  is  light  and  pleasant  work 
for  a  boy  of  ten  or  twelve  years  of  age, 
and  proves  on  actual  trial  a  saving  on 
each  press  to  which  it  is  constant])  used 
of  about  six  dollars  per  week,  and  the 
quantity  of  work  performed  on  one  press 
is  more  than  what  can  be  done  in  the 
usual  way.  One  of  those  machines  has 
been  in  constant  operation  for  7  months, 
and  during  that  period  has  not  required 
one  hour's  attention.  There  is  no  prepa- 
ration necessary,  but  cleaning,  which  is 
performed  in  a  few  minutes.  The  trouble 
of  preparing  new  balls,  and  knocking  up 
balls,  which  on  the  old  plan  consumes  so 
much  time,  is  in  this  machine  totally 
saved.  It  is  computed,  that  in  saving  of 
time,  one  fifth  more  can  be  done  per  day 
than  on  the  old  plan,  with  all  the  superio- 
rities enumerated." 

However  great  the  improvement  may 
appear,  the  roller  can  never  render  the 
printing  or  impression  uniform  5  with  this 
and  other  objections,  the  supposed  im- 
provement is  abandoned,  and,  we  believe, 
the  plan  is  only  used  in  one  or  two  offices. 

PRINTING,  of  Calico.  Calico  printing 
is  the  ait  of  communicating  different  co- 
lours to  particular  spots  or  figures,  on  the 
surface  of  cotton  or  linen  cloth,  while  the 
rest  of  the  stuff'  retains  its  original  white- 
ness. 

This  ingenious  art  seems  to  have  origi- 
nated in  India,  where  we  know  it  has 
been  practised  for  more  than  2000  years. 
It  has  but  lately  been  cultivated  in  Eu- 
rope ;  but  the  enlightened  industry  of 
our  manufacturers,  has  already  improved 
prodigiously,  upon  the  tedious  processes 
of  their  Indian  masters.  No  art  has  arisen 
to  perfection  with  greater  celerity  :  a  hun- 


dred years  ago,  it  was  scarcely  known  in 
Europe  ;  at  present,  the  elegance  of  the 
patterns,  the  beauty  and  permanency  of 
the  colours,  and  the  expedition  with  which 
the  different  operations  are  carried  on, 
are  really  admirable/ 

Calico  printing  consists,  in  impregnat- 
ing those  parts  of  the  cloth,  which  are  to 
receive  a  colour,  with  a  mordant,  and  then 
dyeing  it  as  usual,  with  some  dye  siufT 
or  other.  The  dye  stuff'  attaches  itself 
firmly,  only  to  that  part  of  the  cloth  which 
has  received  the  mordant.  The  whole 
surface  of  the  cotton,  is  indeed  more  or 
less  tinged,  but  by  washing  it,  and  bleach- 
ing it  tor  some  days  on  the  grass,  with 
the  wrong  side  uppermost,  all  the  un- 
mordanted  parts  resume  their  original 
colour,  wliile  tnose  which  have  received 
the  mordant,  retain  it.  Let  us  suppose 
that  a  piece  of  white  cotton  cloth,  is  to 
receive  red  stripes:  all  the  parts  where 
the  stripes  are  to  appear,  are  pencilled 
over  with  a  solution  of  acetite  of  alumine ; 
after  this,  the  cloth  is  dyed,  in  the  usual 
manner  with  madder.  When  taken  out 
of  the  dyeing  vessel,  it  is  all  of  a  red  co- 
lour, but  by  washing  and  bleaching,  the 
madder  leaves  every  part  of  the  cloth 
white,  except  the  stripes  impregnated 
with  the  acetite  of  alumine,  which  remain 
red.  In  the  same  manner  may  yellow 
stripes,  or  any  other  wished-for  figure,  be 
given  to  cloth,  by  substituting  quercitron 
bark,  weld,  &c  for  madder. 

When  different  colours  are  to  be  given, 
to  different  parts  of  the  cloth  at  the  same 
time,  it  is  done  by  impregnating  it  with 
various  mordants.  Thus,  if  stripes  be 
drawn  upon  a  cotton  cloth,  with  acetite  ot 
alumine,  and  other  stripes  with  acetite  of 
iron,  and  the  cloth  be  afterwards  dyed  in 
the  usual  way  with  madder,  and  then 
washed  and  bleached,  it  will  be  striped 
red  and  brown  The  same  mordants  with 
quercitron  bark,  give  yellow  and  olive,  or 
drab. 

The  mordants  employed  in  calico  print- 
ing, are  acetite  of  alumine,  and  acetite 
of  iron,  prepared  in  the  manner  described, 
in  the  article  on  dyeing.  These  mordants 
are  applied  to  the  cloth,  either  with  a  pen- 
cil, or  by  means  of  blocks,  on  which  the 
pattern,  according  to  which  the  cotton  is 
to  be  printed,  is  cut.  As  they  are  applied 
only  to  particular  parts  of  the  cloth,  care 
must  be  taken  that  none  of  them  spread, 
to  the  part  of  the  cloth  which  is  to  be  left 
white,  and  that  they  do  not  interfere  with 
one  another,  when  more  than  one  are  ap- 
plied. If  these  precautions  be  not  attend- 
ed to,  all  the  elegance  and  beauty  of  the 
print  must  be  destroyed.  It  is  neces- 
sary, therefore,  that  the  mordants  should 


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be  of  such  a  degree  of  consistence,  that 
they  will  not  spread  beyond  those  parts 
of  the  cloth,  on  which  they  are  appli- 
ed. This  is  done  by  thickening  them 
with  flour  or  starch,  when  they  are 
to  be  applied  by  the  block ;  and  with 
rum-arabic,  when  they  are  to  be  put  on 
by  a  pencil.  The  thickening  should  ne- 
ver be  greater,  than  is  sufficient  to  pre- 
vent the  spreading  of  the  mordants  ;  w  hen 
carried  too  far,  the  cotton  is  apt  not  to  be 
sufficiently  saturated,  with  he  mordants; 
of  course  the  dye,  takes  but  imper- 
fectly. 

In  order  that  the  parts  of  the  cloth  im- 
pregnated with  mordants,  may  be  distin- 
guished by  their  colour,  it  is  usual  to  tinge 
the  mordants,  with  some  colouring  mat- 
ter or  other.  The  printers  commonly  use 
the  decoction  of  Brazil-wood  for  this  pur- 
pose; but  Dr.  Bancroft  has  objected  to 
this  method,  because  he  thinks  that  the 
Brazil-wood,  colouring  matter,  impedes 
the  subsequent  process  of  dyeing.  It  is 
certain,  that  the  colouring  matter  of  the 
Brazil-wood,  is  displaced  during  that  ope- 
ration, by  the  superior  affinity  of  the  dye 
stuff,  for  the  mordants.  Were  it  not  for 
this  superior  affinity,  the  colour  would 
not  take  at  all.  Dr  Bancroft  advises,  to 
colour  the  mordant  with  some  of  the  dye 
stuff,  afterwards  to  be  applied;  and  he 
cautions  the  using  of  more  for  that  pur- 
pose, than  is  sufficient  to  make  the  mor- 
dant distinguishable,  when  applied  to  the 
cloth.  The  reason  of  this  precaution  is 
obvious.  If  too  much  dye  be  mixed  with 
the  mordant,  a  great  proportion  of  the 
mordant,  will  be  combined  with  colour- 
ing matter,  which  must  weaken  its  affinity 
for  the  cloth,  and  of  course  prevent  it  from 
combining  with  it,  in  sufficient  quantity, 
to  ensure  a  permanent  dye. 

Sometimes  these  two  mordants,  are 
mixed  together  in  different  proportions ; 
and  sometimes  one  or  both  is  mixed  with 
an  infusion  of  sumach,  or  of  nut-galls. 
By  these  contrivances,  a  great  variety  of 
colours  are  produced,  by  the  same  "dye 
stuff. 

After  the  mordants  have  been  applied, 
the  cloth  must  be  completely  dried.  It 
is  proper  for  this  purpose,  to  employ  ar- 
tificial heat,  which  will  contribute  some- 
thing towards  the  separation  of  the  ace- 
tous acid  from  its  base,  and  towards  its 
evaporation,  by  which  the  mordant  will 
combine  in  a  greater  proportion,  and  more 
intimately  with  the  cloth 

When  the  cloth  is  sufficiently  dried,  it 
is  to  be  washed  with  warm  water  and  cow- 
dung,till  all  the  flour, or  gum,employed  to 
thicken  the  mordants,  and  all  those  parts 
r«f  the  mordants,  which  are  uucombined 


with  the  cloth,  be  removed.  The  cow- 
dung  serves  to  entangle  these  loose  parts 
of  the  mordants,  and  to  prevent  them 
from  combining,  with  those  parts  of  the 
cloth  which  are  to  remain  white.  After 
this,  the  cloth  is  thoroughly  rinsed  in  clean 
water. 

Almost  the  only  dye  stuffs  employed 
by  calico  printers,  are  indigo,  madder, 
and  querciti  on  bark,  or  weld.  This  last 
substance,  however,  is  but  little  used  by 
the  printers  of  this  country,  except  for  de- 
licate greenish  yellows.  The  quercitron 
bark  has  almost  superseded  it,  because  it 
gives  colour  equally  good,  and  is  much 
cheaper  and  more  convenient,  not  requir- 
ing so  great  a  heat  to  fix  it.  Indigo  not 
requiring  any  mordant,  is  commonly  ap- 
plied at  once,  either  with  a  block  or  a 
pencil.  It  is  prepared  by  boiling  together 
indigo,  potash  made  caustic  by  quick- 
lime, and  orpiment ;  the  solution  is  after- 
wards thickened  with  gum.  It  must  be 
carefully  secluded  from  the  air,  otherwise 
the  indigo  would  soon  be  regenerated, 
which  would  render  the  solution  useless. 
Dr.  Bancroft  has  proposed  to  substitute 
coarse  brown  sugar  for  orpiments  :  it  is 
equally  efficacious  in  decomposing  the 
indigo,  and  rendering  it  soluble.  ;  while 
it  likewise  serves  all  the  purposes  of 
gum. 

When  the  cloth,  after  being  impregnat- 
ed with  the  mordant,  is  sufficiently  cleans- 
ed, it  is  dyed  in  the  usual  manner  The 
whole  of  it  is  more  or  less  tinged  with  the 
dye  stuff.  It  is  well  washed,  and  then 
spread  out  for  some  days  on  the  grass, 
and  bleached  with  the  wrong  side  upper- 
most. This  carries  the  colour  off  com- 
pletely, from  all  the  parts  of  the  cotton 
which  have  not  imbibed  the  mordant,  and 
1  aves  them  of  their  original  whiteness, 
while  the  mordanted  spots  retain  the  dye 
as  strongly  as  ever. 

Let  us  now  give  an  example  or  two,  of 
the  manner  in  which  the  printers  give 
particular  colours  to  calicoes.  Some  ca- 
licoes are  only  printed  of  om  colour,  others 
have  two,  others  three  or  more,  even  to 
the  number  of  eight,  ten,  or  twelve.  The 
smaller  the  number  of  colours,  the  fewer 
in  general,  are  the  processes. 

1.  One  of  the  most  common  colours  on 
cotton  prints,  is  a  kind  of  nankeen  yellow, 
of  various  shades,  down  to  a  deep  yellow- 
ish brown,  or  drab  It  is  usually  in  stripes 
or  spots.  To  produce  it,  the  printers  be- 
smear a  block,  cut  out  into  the  figure  of 
the  print,  with  acetite  of  iron,  thickened 
with  gum  or  flour :  apply  it  to  the  cotton, 
which,  after  being  dried  and  cleaned  in 
the  usual  manner,  is  plunged  into  a  pot- 
ash ley.   The  quantity  of  acetite  of  iron 


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is  always  proportioned  to  the  depth  of  the 
shade. 

2.  For  yellow,  the  block  is  besmeared 
with  acetite  of  alumine.  The  cloth,  after 
receiving  the  mordant,  is  dyed  with  quer- 
citron bark,  and  then  bleached. 

3.  Red  is  communicated  by  the  same 
process  ;  only  madder  is  substituted  for 
the  bark. 

4.  The  fine  light  blues  which  appear  so 
often  on  printed  cottons,  are  produced  by 
applying-  to  the  cloth,  a  block  besmeared 
with  a  composition,  consisting  partly  oi 
wax,  which  covers  all  those  parts  of  the 
cloth  which  are  to  remain  white.  The 
cloth  is  then  dyed  in  a  cold  indigo  vat ; 
and  after  it  is  dry,  the  wax  composition, 
is  removed  by  hot  water. 

5.  Lilac  flea  brown,  and  blackish  brown, 
are  given  by  means  of  acetite  of  iron ;  the 
quantity  of  which  is  always  proportioned 
to  the  depth  of  the  shade.  For  very  deep 
Colours,  a  little  sumach  is  added.  The 
cotton  is  afterward  dyed  in  the  usual  man- 
ner with  madder,  and  then  bleached. 

6.  Uove  colour  and  drab,  by  acetite  of 
iron,  ana  quercitron  bark. 

When  different  colours  are  to  appear 
in  the  same  print,  a  greater  number  of 
operations  are  necessary.  Two  or  more 
blocks  are  employed,  upon  each  of  which, 
that  part  only  of  the  print  is  cut,  which  is 
to  be  of  somo  particular  colour.  These 
are  besmeared  with  different  mordants, 
and  applied  to  the  cloth,  which  is  after- 
wards dyed  as  usual.  Let  us  suppose  for 
instance,  that  these  blocks  are  applied  to 
cotton,  one  with  acetite  of  alumine,  ano- 
ther with  acetite  of  iron,  a  third  with  a 
mixture  of  those  two  mordants,  and  that 
the  cotton  is  then  dyed  with  quercitron 
bark,  and  bleached.  The  parts  impreg- 
nated with  the  mordants,  would  have  the 
following  colours. 

Acetite  of  alumine,  Yellow. 

  iron,         Olive,  drab,  dove. 

The  mixture,  Olive  green,  olive. 

If  part  of  the  yellow  be  covered  over 
with  the  indigo  liquor,  applied  with  a 
pencil,  it  will  be  converted  into  green.  By 
the  same  liquid,blue  maybe  given  to  such 
parts  of  the  print  as  require  it. 

If  the  cotton  be  dyed  with  madder,  in- 
stead of  quercitron  bark,  the  print  will 
exhibit  the  following  colours. 


for  part  of  the  pattern  are  to  be  applied  ? 

the  cotton  is  then  to  be  dyed  in  the  mad- 
der bath,  and  bleached  ;  then  the  rest  of 
the  mordants,  to  fill  up  the  pattern,  are 
added,  and  the  cloth  is  again  dyed  with 
quercitron  bark,  and  bleached.  The  se- 
cond dyeing  does  not  much  affect  the 
madder  colours :  because  the  mordants, 
liich  render  them  permanent,  are  alrea- 
dy saturated.  The  yellow  tinge  is  easily 
removed,  by  the  subsequent  bleaching. 
Sometimes  a  new  mordant  is  also  applied, 
to  some  of  the  madder  colours,  in  conse- 
quence of  which,  they  receive  a  new  per- 
manent colour  from  the  bark.  After  the 
last  bleaching,  new  colours  may  be  added 
by  means  of  the  indigo  liquor.  The  fol- 
lowing table  will  give  an  idea  of  the  co- 
lours, which  may  be  given  to  cotton  by 
these  complicated  processes. 


L  Madder  Bye. 


Acetite  of  alumine, 

  iron, 

 diluted, 

Both,  mixed, 


Colours. 
Red. 

Brown,  black. 

Lilac. 

Purple. 


Acetite  of  alumine, 
—   iron, 


Red. 

Brown,  black. 
Purple. 


The  mixture, 

When  a  greater  number  of  colours  are 
to  appear ;  for  instance,  when  those  com- 
municated by  bark,  and  those  by  madder, 
are  wanted  at  the  same  time,  mordants 


n.  Bark  Bye. 

Acetite  of  alumine,  Yellow. 

 iron,  Dove,  drab. 

Lilac  and  acetite  of  alu- 
mine, Olive. 

Red  and  acetite  of  alu- 
mine, Orange. 

III.  Indigo  Bye. 

Indigo,  Blue. 

Indigo  and  yellow,  Green. 

Thus  no  less  than  12  colours  may  be 
made  to  appear  together  in  the  same  print, 
by  these  different  processes. 

.  These  instances  will  serve,  to  give  the 
reader  an  idea  of  the  nature  of  calico  print- 
ing, and  at  the  same  time  afford  an  ex- 
cellent illustration,  of  the  importance  of 
mordants  in  dyeing. 

If  it  were  possible  to  procure  colours 
j  sufficiently  permanent,  by  applying  them 
i  at  once  to  the  cloth,  by  the  block  or  the 
pencil,  as  is  the  case  with  the  mordants, 
the  art  of  calico  printing,  would  be  brought 
to  the  greatest  possible  simplicity  ;  but 
at  present,  this  can  only  be  done  in  one 
case,  that  of  indigo ;  every  other  colour 
requires  dyeing.  Compositions,  indeed, 
may  be  made,  by  previously  combining 
the  dye  stuff,  and  the  mordants.  Thus 
yellow  may  be  applied  at  once,  by  employ- 
ing a  mixture  of  the  infusion  of  quercitron 
bark,  and  acetite  of  alumine  ;  red,  by 
mixing  the  same  mordant,  with  the  de- 
coction  of  alumine,  and  so  on.   The  co- 


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lours  applied  in  this  way,  are  unfortunate- 
ly, far  inferior  in  permanency,  to  those 
produced  when  the  mordant  is  previous- 
ly combined  with  the  cloth,  and  the  dye 
stuff  afterwards  applied  separately.  In 
this  way  are  applied,  almost  all  the  fugi- 
tive colours  of  calicoes,  which  washing",  or 
even  exposure  to  the  air  destroys. 

As  the  application  of  colours  in  this 
way,  cannot  always  be  avoided  by  calico 
printers,  every  method  of  rendering  them 
more  permanent,  is  an  object  of  impor- 
tance. 

On  the  subject  of  calico  printing,  the 
reader  may  find  some  useful  observations 
in  the  American  edition  of  Willich's  Do- 
mestic Encyclopedia,  drawn  up  principal- 
ly by  the  now  professor  Cooper.  The  re- 
marks already  given  in  the  preceding  ac 
count,  may  prove  useful  by  the  following 
additional  observations  extracted  from 
Aikin's  Chemical  Dictionary. 

To  apply  a  coloured  pattern  on  a  white 
or  coloured  ground,  only  two  general  me- 
thods appear  practicable,  the  one,  to 
weave  the  pattern  into  the  cloth  with 
threads  dyed  of  the  requisite  colours,  the 
other  to  devise  some  method  of  topical 
dyeing,  which  shall,  like  a  picture,  con- 
fine the  desired  colours  to  those  parts  on- 
ly that  are  figured  by  the  intended  pat- 
terns. The  former  is  the  delicate  busi- 
ness of  the  embroiderer  or  the  tapestry 
weaver  ;  the  latter  is  the  ingenious  art  of 
the  calico-printer. 

It  is  particularly,  though  not  entirely, 
with  the  adjective  colours,  or  those  that 
require  a  mordant,  that  calico-printing  is 
concerned,  as  this  very  circumstance  af- 
fords a  ready  method  of  giving  a  perma- 
nent colour  only  to  the  pattern  part;  for 
if  this  latter  only  is  impregnated  with  the 
mordant,  and  the  whole  cloth  is  then  uni- 
formly dyed,  the  natural  effect  of  expo- 
sure to  sun  and  air,  will  be  to  discharge 
all  the  colour  from  every  part  of  the  cloth 
except  where  it  had  previously  received 
the  mordant,  and  thus  a  coloured  pattern 
will  be  produced  on  a  white  ground. 

This  partial  application  of  mordants, 
therefore,  followed  by  general  dyeing, 
constitutes  the  greater  part  of  calico- 
printing,  besides  which,  however,  a  fur- 
ther variety  of  application  often  occurs, 
as  sometimes  colours  themselves  are 
painted  or  pencilled  in  to  assist  the  gene- 
ral effect,  which  therefore  require  no  sub- 
sequent operation ;  and  occasionally  other 
contrivances  are  used  to  fix,  or  alter,  or 
discharge  colours,  according  as  the  pro- 
posed pattern  may  require  it. 

Two  mordants  are  more  particularly 
used  by  calico-printers,  though  equally 
serviceable  in  general  dyeing,  the  one  is 


acetite  of  alumine  with  a  portion  of  alum, 
the  other  is  a  solution  of  iron  in  some  ve- 
getable acid. 

The  acetite  of  alumine  is  always  made 
by  double  decomposition  of  alum  and  su- 
gar of  lead,  but  the  proportions  of  each 
vary  much,  according  to  circumstances, 
and  probably  to  the  fancy  of  the  colour- 
mixer.    In  general,  three  pounds  of  alum 
(or  in  that  proportion)  are  thrown  into  a 
barrel,  and  when  dissolved,  a  pound  to  a 
pound  and  a  half  of  sugar  of  lead  are 
added,  and  the  whole  often  stirred  for 
two  days.    On  settling,  a  clear  liquor  is 
found  at  top  which  consists  of  acetite  of 
alumine,  but  still  containing  much  unde- 
composed  alum,  and  a  dense  white  sedi- 
ment remains  at  bottom,  which  is  sulphat 
of  lead.  The  clear  liquor  is  the  part  used 
for  the  mordant,  but  previously  two 
ounces  of  pearlash  and  as  much  chalk  are 
added,  more  entirely  to  neutralize  any  ex- 
cess of  acid,  and  partly  to  decompose  the 
solution  ;  for  though  "the  mordant  must 
be  in  a  saline  state  entirely  to  fix  itself  to 
the  fibres  of  the  cotton,  it  should  seem 
that  the  true  intermede  between  the  cot- 
ton and  the  dye  is  the  alumine,  and  not 
the  acids  that  hold  it  in  solution,  and 
hence  the  weaker  the  adhesion  of  these 
is  to  the  alumine,  and  the  stronger  will 
be  the  triple  union  between  the  colour, 
the  earth,  and  the  cotton  fibre. 

The  other  mordant  constantly  in  use 
with  the  printers  is  a  solution  of  iron  in 
vinegar,  soured  beer,  pyroligneous  acid, 
or  other  vegetable  acids,  and  which  there- 
fore is  chiefly  an  acetite  of  iron  mixed 
with  a  portion  of  tartrite,  perhaps  gallat, 
and  other  salts  of  this  metal. 

To  make  th  se  mordants  fit  for  print- 
ing, and  give  them  such  a  consistence  as 
will  enable  them  to  dry  in  a  figured  pat- 
tern without  running  into  the  adjoining 
parts,  they  are  thickened  with  paste  to 
the  consistence  of  jelly;  and  when  to  be 
used,  this  jelly  is  squeezed  through  a 
very  fine  sieve  by  a  particular  and  simple 
contrivance,  on  the  surface  of  which  it 
lies  as  a  thin  coating  convenient  to  be 
transferred  to  the  printing  blocks. 

The  mordant,  when  naturally  colour- 
less, is  a  little  tinged  with  Brazil  wood 
(which  being  a  very  fugitive  dye  does  not 
impair  the  general  effect)  that  the  work- 
man may  see  the  impression  on  the  cloth 
and  fix  the  pattern  with  accuracy. 

The  instrument  by  which  the  impres- 
sion  is  given  (or  what  answers  to  the  types 
in  the  printing  of  books)  is  a  piece  of 
hard  wood,  generally  holly,  about  a  foot 
long,  on  which  the  pattern  is  carved,  near- 
ly as  in  wood  engraving,  and  is  strength- 
ened at  the  back  with  a  thicker  piece  of 


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PRI 


oak  glued  on.  The  parts  of  the  pattern  f  minous  mordant  alone,  a  second  with  the 
that  are  to  receive  a  large  body  of  colour,  mixture  of  the  former  mordant  with  iron 
and  consequently  require  a  correspond-  i  liquor,  a  third  with  iron  liquor  alone,  and 
frig  quantity  of  mordant,  are  given  by  ;  a  fourth  with  iron  liquor  and  galls,  and 
pieces  of  old  hat  inlaid  into  the  block,  j  the  piece  be  afterwards  dyed  with  quer- 
which  are  found  to  take  up  the  mordant :  citron  or  weld,  and  the  ground  bleached 
in  a  more  uniform  way  than  any  other  ma-  in  the  usual  manner,  the  first  pattern  will 
terial  Of  late  years  also  some  of  the  j  be  of  a  pure  yellow,  the  second  will  be 
finer  patterns  are  given  by  sheet-copper  i  olive,  the  third  of  a  dark  drab  colour, 
fixed  on  a  block   like  fillagree  work,  j  and  the  fourth  nearly  black,  whilst  the 

ground  will  be  white. 

Cloth  that  has  been  thus  printed  with 
one  course  of  colours,  is  often  subjected 
to  a  similar  process  tor  a  different  course 
with  another  dye,  where  the  intended  pat- 
tern requires  a  great  variety  of  colours. 

Thus  when  all  the  reds,  purples, 
browns,  &c.  have  been  given  by  a  course 
of  madder,  the  cloth  with  part  of  the  pat- 
terns thus  finished,  may  be  made  to  under- 
go a  course  of  mordants  to  be  afterwards 
dyed  with  quercitron  for  other  parts  of 
the  pattern.  In  this  case,  however,  much 
judgment  is  required  to  employ  only  those 
successions  winch  will  not  materially  in- 
jure each  other.  It  might  be  at  first  sup- 
posed, that  when  a  pattern  dyed  red  (for 
example)  with  madder  and  an  alum  mor- 
dant came  to  be  immersed  in  a  decoction 
of  weld  without  any  fresh  mordant,  that 
the  former  would  not  be  at  all  affected  by 
the  latter,  or  at  least  that  the  effect  would 
soon  be  dest'.  oyed  by  bleaching ;  but  this 
is  not  found  to  be  altogether  the  case,  for 
adjective  colours  appear  to  have  also  their 


on  a 

which  gives  a  finer  and  sharper  line  to 
the  figured  pattern.  Fine  work  is  some- 
times given  still  more  expeditiously  by 
engraved  copper-plate  and  the  rolling- 
press  as  in  common  picture  engraving. 

The  general  process  of  the  simple  kind 
of  calico-printing,  therefore,  is  the  follow- 
ing :  the  cotton  cloth,  previously  bleach- 
ed with  alkali  and  much  washing,  and  ca- 
lendered to  smooth  the  surface,  is  stretch- 
ed on  a  long  table  covered  with  w  oollen 
cloth,  when  the  printer  first  lays  the  block 
on  tiie  sieve  that  contains  the  mordant, 
then  applies  it  steadily  on  the  cloth,  and 
strikes  it  a  smart  blow  on  the  back  with 
a  wooden  mallet  to  give  a  strong  impres- 
sion. This  he  repeats  successively,  each 
time  carefully  laying  the  block  in  the  pro- 
per direction  so  as  not  to  overlap  the  last 
impression,  till  the  whole  is  finished. 

In  this  way  the  patterns  are  impressed 
with  one  or  more  kinds  of  mordant  as 
may  be  required,  after  which  the  cloth  is 
strongly  dried  in  a  stoved  room,  which 
both  fixes  the  mordant  more  firmly  to  the 


cotton,  and  volatilizes  much  of  the  ace- !  relative  affinities  for  mordants,  therefore 


tous  acid  in  fumes  very  sensible  to  the 
smell.  When  dry,  the  cloth  is  taken  to  a 
cistern  containing  very  warm  water,  in 
which  cow-dung  is  diffused,  and  there  it 
is  worked  about  to  dissolve  out  the  paste 
and  other  superfluous  part  of  the  mor- 
dant, sufficient  being  yet  left  firmly  united  j 


as  a  fast  madder  red  is  a  compound  of 
alum  and  alumine,  if  madder  has  a  less 
affinity  for  alumine  than  w  eld,  the  colour 
will  be  in  part  decomposed,  and  some  of 
the  weld  will  displace  a  portion  of  the 
madder,  Hence  the  colour  will  be  chang- 
ed into  a  triple  compound  of  madder, 


to  the  fibres  of  the  cloth  to  fix  the  dye  in  \  weld,  and  alumine,  and  the  dye  propor- 
the  subsequent  process.  The  cloth  is  j  tionally  altered  It  appears,  therefore, 
then  rinced  and  thoroughly  cleaned,  after  I  that  in  printing  successive  courses  of  co- 
which  it  is  dyed  in  the  usual  way.  The  j  lours,  attention  should  be  paid  to  print 
cloth  comes  out  of  the  dyeing  cistern  en-  j  first  those  whose  affinities  for  the  mor- 
tireiy  cohered  (yellow,  for  example,  when  i  dants  are  the  strongest,  and  finish  with 
the  dye  has  been  weld)  ;  it  is  then  again  \  the  weakest,  unless  indeed  (which  is  some- 
washed  with  water,  boiled  with  bran  and  times  the  case)  the  change  produced  by 
water,  alternating  with  exposure  to  air  on  j  the  intermixture  of  colours  be  a  part  of 
the  bleach-field,  and  other  bleaching  pro-  j  the  desired  effect.  But  much  remains  to 
cesses,  till  at  last  all  the  colour  of  the  !  be  done  towards  a  rational  explanation  of 
ground  has  disappeared,  and  that  only  re-  j  the  complicated  affinities  and  mutual  ac- 


mains  which  has  been  fixed  to  the  pattern 
by  the  mordant. 

The  above  is  the  simplest  process,  that 
is,  in  which  all  the  mordants  are  laid  on 
first,  and  the  colour  is  given  by  a  single 
dyeing  afterwards,  and  by  merely  varying 
the  mordants  a  considerable  variety  of 
shades  may  be  given.  Thus,  for  exam- 
ple, if  one  pattern  be  printed  with  the  alu- 


tion  of  mordants  and  colouring  matter, 
and  of  the  apparently  slight  variations  by 
which,  however,  the  skilful  printer  is  ena- 
bled to  produce  effects  which  at  present 
a  person  could  hardly  hope  to  imitate 
without  a  large  share  of  practical  expe- 
rience. 

Another  part  of  calico-printing  is  the 
impression  of  colours s  for  hitherto  that  of 


PRI 

mordants  only  has  been  mentioned.  In 
this  case  also,  as  in  general  dyeing,  the 
substantive  colours  do  not,  and  the  adjec- 
tive colours  do,  require  to  be  previously 
mixed  with  their  proper  mordant.  Pat- 
tern colours  are  applied  either  by  the 
block  (as  the  mordants  are)  or  by  pencil- 
ling or  painting.  In  the  latter  case  the  co- 
lour is  thickened,  not  with  paste,  but  with 
gum  arabic  or  Se  negal,  and  it  is  applied 
with  a  camel's  hair  brush.  The  pencilled 
colours  require  no  further  dyeing  opera- 
tion, and  are  only  finished  by  washing  and 
drying,  so  that  it  is  usually  the  last  parts 
of  the  pattern,  that  are  given  in  this  way. 

Indigo  is  the  only  substantive  colour 
used  for  pencilling,  but  here  a  very  great 
difficulty  presents  itself;  for  indigo  (as 
already  mentioned  in  describing  the  blue 
dye)  is  only  a  fast  colour  when  in  its  dis- 
oxygenated  state,  in  which  it  is  yellow  or 
green  ;  but  when  much  exposed  to  air,  as 
can  hardly  be  avoided  in  the  slow  and  mi- 
nute process  of  pencilling,  part  of  it  re- 
turns to  the  blue  or  oxygenated  state  be- 
fore it  has  properly  fixed  itself  on  the 
stuff,  and  this  portion  is  carried  away  in 
the  subsequent  washing.  It  is  therefore 
very  seldom  that  the  pattern  of  a  whole 
piece  can  be  indigo-pencilled  with  the 
same  uniformity  with  which  some  of  the 
other  colours  are  given  The  solution 
used  for  this  purpose  is  usually  made  of 
a  large  proportion  of  indigo  dissolved  in 
potash,  rendered  caustic  by  lime,  to  which 
is  added  orpiment  for  the  deoxygenation 
of  the  indigo.  This  latter  effect  is  also 
often  produced  wholly  or  in  part,  by  the 
cheaper  kind  of  raisins.  The  solution  is 
then  thickened  by  gum,  and  should  be 
kept  in  a  close  stopped  vessel,  and  no 
more  exposed  to  air  than  is  necessary  for 
immediate  use. 

This  indigo-blue  is  also  often  pencilled 
upon  figures  previously  dyed  yellow  in  or- 
der to  produce  a  permanent  green,  but 
with  some  little  injury  to  the  yellow 
ground  by  the  caustic  alkali  contained  in 
the  indigo  solution. 

Adjective  colours  are  sometimes  mixed 
with  their  proper  mordant,  and  used  in 
this  state  for  pencilling  without  any  other 
preparation.  Such  a  mixture  has"  there- 
fore the  effect  of  a  substantive  colour. 
Thus  if  a  very  strong  decoction  of  weld 
or  quercitron  is  added  to  a  mixture  of 
alum  and  sugar  of  lead,  and  the  whole 
duly  thickened,  a  yellow  of  a  certain  de- 
gree of  durability  is  formed  at  once,  and 
may  be  printed  or  pencilled  on  a  white 
ground  to  produce  a  yellow,  on  an  indigo 
ground  to  give  a  green,  on  a  red  madder 
ground  to  give  an  orange,  and  the  like. 

It  is  found,  however,  that  adjective  co- 


PUI 

lours,  when  first  fixed  with  their  mor- 
dants, and  then  applied  to  cotton,  have 
very  little  durability  compared  to  that  of 
the  method  of  first  applying  the  mordant 
thoroughly,  and  then  the  colour.  This  dif- 
ference holds  good  in  the  general  as  well 
as  topical  dyeing  of  cotton  and  linen  with 
ail  adjective  colours,  as  has  already  been 
fully  described,  though  with  regard  to 
wool  it  appears  to  be  often  a  matter  of  in- 
difference as  to  the  fixity  of  the  colour, 
whether  the  mordant  and  the  dye  are  ap- 
plied separately  or  united.  Thus  woollen 
cloth  may  be  dyed  with  cochineal  and  tin, 
apparently  equally  well  in  one  as  in  two 
operations.  But  as  this  does  not  hold 
with  cotton,  it  still  remains  a  great  object 
in  calico-printing  to  discover  some  method 
of  pencilling  adjective  colours  so  as  to  be 
sufficiently  durable.  It  is  also  an  addi- 
tional difficulty  to  this  object,  that  the 
pencilled  colours  always  require  a  very 
full  body  of  colour,  being  generally  ap- 
plied rather  as  finishing  touches  to  the 
pattern  than  constituting  any  very  large 
portion  of  it 

In  many  cases  parts  of  the  pattern  it- 
self are  required  to  be  white.  Sometimes 
this  may  be  done  simply  in  the  way  that 
the  ground  is  left  white,  that  is,  by  leav- 
ing these  parts  untouched  by  any  mor- 
dant, so  that  when  the  whole  is  dyed  with 
an  adjective  colour,  subsequent  washing 
and  bleaching  will  destroy  the  dye  on 
these  untouched  parts.  This  plan,  how- 
ever, is  obviously  inadmissible  when  the 
general  dye  is  given  by  a  substantive  co- 
lour as  indigo.  In  such  cases  some  kind 
of  covering  must  be  applied  to  the  white 
pattern  parts  to  protect  them  from  the 
dye,  and  hinder  it  from  penetrating.  In 
the  East  Indies  wax  is  often  used  topical- 
ly on  the  white  parts  for  this  purpose.  In 
this  country  a  mixture  of  pipe  clay  and 
paste  is  sometimes  used.  In  these  cases 
the  cold  indigo  vat  is  of  particular  ser- 
vice, as  the  covering  for  the  white  is  much 
less  liable  to  be  dissolved  out,  than  in  the 
usual  way  of  dyeing  in  a  heated  bath. 

But  in  the  common  method  of  produc- 
ing white  with  adjective  colours,  the 
smaller  parts  of  the  pattern  are  seldom  so 
well  defined  and  thoroughly  bleached  as 
to  render  the  work  perfect.  With  every 
care  some  part  of  the  adjoining  printed 
mordant  will  often  spread  a  little  beyond 
its  proper  limits,  and  occasion  a  perma- 
nent soil  on  the  white,  besides  that  the 
removing  some  stains  by  bleaching,  parti- 
cularly those  from  the  weld  bath,  is  te- 
dious and  difficult  To  remedy  this, 
therefore,  and  to  give  a  perfectly  clear 
and  well  defined  pattern  white  to  the 
parts  without  mordant,  which  so  much 


PRU 


PUM 


improves  the  general  effect,  the  bleaching 
power  of  acids  has  lately  been  much  re- 
sorted to.  Most  of  the  acids  possess  this 
power,  but  the  stronger  mineral  acids  are 
so  liable  to  affect  the  texture  of  the  cot- 
ton when  sufficiently  strong,  that  they 
cannot  be  employed.  Recourse,  there- 
fore,  has  been  had  to  the  stronger  vegeta- 
ble acids,  and  of  these  the  Citric,  either 
in  its  crystallised  state,  or  merely  as  lemon 
juice  concentrated  by  boiling,  holds  the 
first  place,  and  this  article  has  of  late 
years  been  consumed  by  the  printers  of 
England  to  a  vast  amount.  It  is  usually 
applied  by  the  block  like  the  common 
mordants.  The  particulars  of  the  prepa- 
ration of  the  Citric  acid  are  described  un- 
der that  article. 

PRINTS,  Cleansing  of. — Various  me- 
thods have  been  recommended  for  clean- 
sing prints.  Some  observations  to  this 
purpose  have  been  given  in  the  article 
Picture.  We  will  only  add,  in  this 
place,  that  the  best  met.ns  consists  in  im- 
mersing them  for  a  short  time  in  weak 
oxygenized  muriatic  acid.  The  prepara- 
tion of  this  acid  may  be  seen  in  the  article; 
also  in  the  article  Bleaching, and  in  the 
Appendix  to  vol.  i. 

PROGNOSTICS  of  the  Weather.  See 
Meteorology. 

PROP.    See  Mechanical  Powers. 

PRUSSIC  ACID  — This  acid  is  impor- 
tant in  the  arts  only  as  respects  its  com- 
bination with  iron,  in  the  formation  of 
Prussian  blue.  It  is  found  chiefly  during 
the  decomposition  of  animal  substances  at 
high  temperatures.  The  following  is  the 
process  generally  used,  which  is  effected 
by  the.  decomposition  of  prussiat  of  iron. 
For  the  preparation  of  prussiat  of  iron, 
see  Prussian  blue,  art.  Colour-makixg. 

Mix  two  ounces  of  red  precipitate  of 
mercury  with  four  ounces  finely  powder- 
ed Prussian  blue,  and  boil  the  mixture 
with  twelve  ounces  of  water  in  a  glass 
vessel,  shaken  frequently.  Filter  the  so- 
lution, which  is  a  prussiate  of  mercury, 
while  hot;  and,  when  cool,  add  to  it  two 
ounces  of  iron  filings,  and  six  or  seven 
drachms  of  sulphuric  acid;  shake  these 
together,  decant  the  clear  liquor  into  a 
retort,  and  distil  off  one-fourth  of  the  li- 
quor. The  distilled  liquor  is  the  prussic 
acid,  which  has  a  peculiar  smell,  a  sweet 
taste,  and  does  not,  like  other  acids,  red- 
den vegetable  blue  colours,  but  combining 
with  alkalies  and  earths.  In  addition  to 
its  combination  with  iron  as  a  pigment, 
we  may  mention  also  that  its  combination 
with  copper  furnishes  a  brown  pigment, 
which  has  lately  been  introduced  into  use. 

PRUSSIAN  BLUE. — See  Colour- 
making. 


PRUSSIAN  BROWN. — This  prepara- 
tion we  have  so  named  from  the  combina. 
tion  of  prussic  acid  with  a  metallic  base, 
which  is  copper.  It  is  made  by  adding  a 
solution  of  prussian  alkali  (made  by  cal- 
cining blood,  or  bones,  with  potash,)  to 
another  solution  of  sulphate  of  copper  or 
blue  vitriol.  The  effect  is  a  mutual  de- 
composition, and  the  precipitation  of  oxyd 
of  copper  in  union  with  prussic  acid.  We 
have  already  spoken  of  its  use  as  a  pig- 
ment ;  by  some  it  is  considered  superior 
to  the  finer  ochres,  or  browns. 

PRUSSIAN  ALKALI,  or  Prussiat  of 
Potash. — This  preparation  is  used  in  the 
manufacture  of  prussian  blue ;  but,  for  the 
nicer  purposes  of  chemistry,  the  mode  of 
preparing,  differs  from  that  already  no- 
ticed.   See  Tests. 

PULLEY.    See  Mechanics. 

PUMICE  PRESS— A  new  pumice- 
press  was  invented  by  Mr.  Timothy  Mat- 
lack,  formerly  of  Lancaster,  but  now  of 
this  city.  The  common  press,  called  also 
the  cyder-press,  is  well  known  ;  but  we 
shall  add  a  few  observations  on  the  im- 
provement of  Mr.  Matlack.  The  press 
was  intended  originally  for  making  wines 
from  currants,  black  berries,  grapes,  and 
other  small  fruits,  which  he  afterwards 
extended  for  the  making  of  perry,  and 
cyder.  Mr.  M.  adds,  that  it  is  capable  of 
almost  incredible  force,  within  a  small 
space,  by  very  simple  means,  and  at  a  very 
small  expense;  and  also,  thai  it  can  be 
used  with  the  greatest  facility,  and  when 
done  with  for  the  season,  can  be  laid  se- 
curely by,  without  occupying  much  house 
room.  The  press  consists  of  a  double  le- 
ver, which  is  to  press  40  for  1.  The  crib, 
in  which  the  fruit  is  put,  may  contain  40 
bushels,  which  may  be  wrought  at  least 
three  times,  while  one  of  80  bushels  can 
be  wrought  once  in  the  common  mode. 
The  crib  is  21  inches  by  20,  and  20  inches 
high.  The  first  lever,  which  immediate- 
ly acts  upon  the  pumice  placed  in  the 
crib,  is  six  feet  eight  inches,  equal  to  five 
times  the  length  below  the  fulcrum.  The 
second  lever  is  six  feet  eight  inches,  and 
is  connected  to  the  first  by  a  chain  We 
shall  state,  in  the  words  of  the  inventor, 
some  particulars  relative  to  the  power. 

"The  pressure  of  the  weight  (100  lbs.) 
on  the  pumice,  is  as  five  times  five  to  one; 
that  is,  its  pressure  downwards  is  equal 
to  2,500  pounds.  But,  the  uprights  being 
fastened  to  the  side  planks,  the  toe  of  each 
lever  bears  the  crib  upwards  with  the 
same  power  as  the  heel  (or  fulcrum) 
presses  downwards ;  so  that  the  actual 
pressure  on  the  pumice  is  equal  to  5,000 
pounds.  The  pi  ess  is  prov  ided  with  two 
of  these  compound  levers,  acting  side  by 


V 


PUZ 


side,  and  consequently  press  equal  to 
5,000  pounds  ;  although  the  uprights  are 
five  inches  apart,  and  by  lengthening  the 
pin  which  supports  the  leveis  only  five 
inches,  two  more  of  those  levers  may  be 
added  on  the  outsides  of  the  uprights, 
which  will  press  equal  to  another  10,000 
pound,  and  so  infinitely."  For  further 
remarks,  and  a  view  of  the  machine,  see 
the  Transactions  of  the  Agricultural  So- 
ciety of  Philadelphia,  vol.  i,  page  109. 

PUMICE  STONE. — The  pumice  stone, 
though  universally  admitted  to  be  the 
product  of  volcanic  lire,  is  one  of  those 
bodies  which  have  divided  the  opinion  of 
naturalists.  The  \bbc  Lazaro  Spallanza- 
7ii,  who  most  minutely  examined  this  arti- 
cle, says,  that  the  pumice  fields  where 
the  common  pumice  is  found,  consist  of 
an  aggregation  of  numerous  beds  or  strata 
of  pumices,  each  bed  not  forming  a  dis- 
tinct whole,  but  being  a  collection  of  balls 
of  pumice,  without  adhesion  ;  from  which 
he  deduces  that  they  were  thrown  out  by 
the  volcano,  in  a  state  of  fusion  ;  and  took 
a  globose  form  in  the  air.  They  are  of 
different  sizes,  from  that  of  a  nut  to  a  foot 
and  more  in  diameter.  Though  the  ground 
colour  of  them  all  is  white,  in  some  it  in- 
clines to  yellow,  and  in  others  to  a  gray. 
They  swim  in  water,  and  do  not  give  fire 
with  steel.  Their  fracture  is  dry,  and 
rough  to  the  touch,  their  angles  and  thin- 
ner parts  slightly  transparent.  Some  are 
so  compact,  that  the  smallest  pore  is  not 
visible,  nor  do  they  exhibit  the  least  trace 
of  a  filamentous  texture ;  others  on  the 
contrary  are  full  of  pores  and  vacuities, 
and  their  texture  is  formed  by  filaments 
and  streaks,  in  general  parallel  to  each 
other,  of  a  shining  silvery  whiteness. 

This  is  the  common  pumice  stone  known 
amongst  us,  and  the  only  kind  constituting 
an  article  of  commerce  from  the  Mediter- 
ranean to  this  country. 

There  are  several  other  varieties,  par- 
ticularly one  of  a  dark  dirty,  and  another, 
of  a  pale  red  colour ;  both  to  be  found, 
not  loose,  but  in  solid  beds,  and  cut  by 
the  labourers  'm  form  of  parallelopipeds. 
Both  the  latter  sorts  are  used  in  Italy  for 
building  arched  vaults,  cornices,  &c.  but 
do  not  constitute  an  article  of  foreign 
commerce. 

According  to  Klaproth,  pumice  is  com- 
posed of  77.5  of  silex,  17.5  alumine,  and 
1.75  oxyd  of  iron. 

The  greatest  quantity  of  pumice  to  be 
met  with  any  where  is  at  the  Campo  Bian- 
co, in  the  island  of  Lipari,  a  mountain  about 
a  quarter  of  a  mile  in  breadth.  The  rock 
also,  upon  which  the  castle  of  Lipari  is 
built,  is  an  immense  heap  of  lava,  glass, 
VOL,  II. 


and  pumice  stones ;  which  latter,  in  fact, 
are  nothing  else  but  an  imperfect  glass, 
or  a  volcanous  ejection,  which,  if  exposed 
to  a  greater  degiee  of  heat,  would  have 
been  changed  into  a  vitreous  mass.  Small 
quantities  of  pumice  are  found  also  in  the 
Arso,  in  the  island  of  Jschia.  But  a  place 
in  Europe,  which  in  the  abundance  of  its 
'  pumices  can  equal,  or  perhaps  surpass  Li- 
|  pari,  is  the  island  of  Santorine  in  the  Ar- 
;  chipelago,  almost  covered  with  pumice 
stone.    Many  eruptions  of  pumices  are  in 
;  the  Phlegrean  held ;  one  of  which  over- 
|  whelmed  the  unfortunate  town  of  Pom- 
I  Pen- 

Pumice  stone  is  used  in  several  mecha- 
'  nical  arts;  as,  for  rubbing  and  smoothing 
the  surface  of  metals,  wood,  pasteboard, 
j  and  stone  ;  for  which  it  is  well  qualified 
i  by  reason  of  its  harsh  and  brittle  texture. 

PUMP  See  Hydraulics,  and  Eh- 
i  gine  for  raising  Water. 

PUMP,  Forcing  See  Hydraulics. 
J     PURPLE,  in  Dyeing.    See  Dyeing. 

PUTTY,  for  Glaziers,  is  a  mixture  of 
'.  whiting  and  linseed  oil,  combined  toge- 
j  ther  in  proper  proportions. 

PUTTY,  Polishing.— -This  preparation 
is  made  by  calcining  an  alloy  of  equal 
I  parts  of  tin  and  lead,  but  it  is  said  to  be 
j  made,  when  genuine,  by  the  calcination 
I  of  tin  only.    A  white  powder  is  thus  pro- 
duced that  is  the  base  of  most  of  the 
opake  enamels,  and  is  also  used  in  the 
polishing  of  metals,  stones,  and  glass. 

PUZZOLANA— This  is  a  volcanic  pro- 
duction of  a  gray,  brown,  yellowish,  or 
blackish  colour,  loose,  granular,  or  dusty 
and  rough,  porous  and  spongy,  resembling 
a  clay  hardened  in  fire,  and  then  reduced 
to  a  gross  powder.  It  contains,  mixed 
with  it,  various  heterogeneous  substances. 
Its  specific  gravity  is  from  2.5  to  2  8  and 
it  is  in  some  degree  magnetic  :  it  scarcely 
effervesces  with  acids,  though  partially 
soluble  in  them  :  it  melts  easily  per  se : 
but  its  most  distinguishing  property  is, 
that  it  hardens  very  suddenly  when  mix- 
ed with  one-third  of  its  weight  of  lime  and 
water,  and  forms  a  cement  which  is  more 
durable  in  water  than  any  other.  Accord- 
ing to  Bergman's  analysis,  one  hundred 
parts  of  it  contain  from  55  to  60  of  sili- 
ceous earth,  19  or  20  of  argillaceous,  5  oi- 
6  of  calcareous,  and  from  15  to  20  of  iron. 
It  is  evidently  a  martial  argillaceous  marl 
that  has  suffered  a  moderate  heat.  Its 
hardening  power  arises  from  the  dry  state 
of  the  half-baked  argillaceous  particles, 
which  makes  ihem  imbibe  water  very  ra- 
pidly, and  thus  accelerates  the  desicca- 
tion of  the  calcareous  part;  and  also  from 
the  quantity  and  state  of  the  irom  con- 


vvz 


PUZ 


tained  in  it.  It  is  found  not  only  in  Italy, 
but  also  in  France,  in  the  provinces  of 
Auvergne  and  Limoges,  and  elsewhere. 

Not  only  the  volcanic  puzzolana,  but 
the  poor  siliceous  iron-stones  are  capable 
of  forming  a  very  hard  cement,  that  will 
set  in  water.  They  should  be  calcined  so 
as  to  be  of  a  deep  brown  for  this  use ;  if 
more  slightly  torrefied,  they  make  a  very 
hard  cement  in  the  open  air- 
Many  experiments  have  proved  to  M.* 
Dodun  that  the  puzzolana,  which  soonest 
forms  a  body  in  the  water,  is  not  fit  to  be 
employed  in  the  open  air,  where  it  cracks 
and  chaps  in  all  directions  And  that 
which  is  proper  for  the  air,  and  which  ac- 
quires and  preserves  its  tenacity  in  it,  sets 
but  imperfectly  in  water.  This' difficulty, 
of  which  the  Institute  perceived  the  cause, 
has  obliged  him  to  keep  two  sorts  of  the 
factitious  puzzolana;  on  the  reciprocal 
use  of  which  a  memoir  of  instruction  ac- 
companies the  sale.  The  two  sorts  may 
be  distinguished  by  their  colour. 

The  factitious  puzzolana  proper  for 
works  under  water,  is  of  a  reddisli  brown. 
That  which  is  fit  for  work  exposed  to  the 
air,  is  a  dark  violet,  The  latter  is  used 
for  terraces,  the  embankments  of  basons, 
for  the  composition  of  inclosures,  or  for 
light  roofs.  Bridges  of  a  single  arch  may 
be  formed  with  it ;  and  it  adheres  so 
strongly  to  glazed  tiles,  that  it  is  some- 
times necessary  to  break  the  tiles  to  de- 
tach it. 

The  puzzolana  proper  for  constructions 
beneath  the  water,  forms  the  most  solid 
body  in  it.  Three  months  after  immersion 
it  is  an  actual  stone,  capable  of  receiving 
a  polish  The  lime  in  it  is  always  rege- 
nerated into  carbonate  of  lime  in  ten 
weeks. 

When  it  may  be  thought  by  any  one 
that  he  has  been  deceived  as  to  the  cer- 
tainty of  these  effects,  it  will  always  be 
found,  that  he  either  has  not  observed  the 
quantities  directed  of  the  puzzolana  and 
the  lime,  or  that  he  has  used  the  reverse 
of  that  kind  of  the  cement  proper  for  the 
work. 

M.  Dodun  commonly  used  lime  in  the 
state  of  impalpable  powder,  slacked  in 
Lafaye's  manner,  for  works  exposed  to 
the  air  ;  and  employed  lime  in  the  state  of 
putty,  for  works  which  were  to  be  cover- 
ed with  water.  Sometimes  he  used  lime 
in  powder  for  the  same  work.  This  dif- 
ference depends  on  the  degree  of  good- 
ness of  the  lime,  on  its  greater  or  lesser 
richness,  or  its  proportional  poverty.  Cus- 
tom gives  the  advantage  of  knowing  the 
different  kinds  on  mere  inspection. 

The  use  of  lime  in  powder  appeared  to 
&m  to  merit  a  preference  in  the  prepara- 


tion of  mortars  or  cements.  He  prepared 
his  factitious  puzzolana  in  a  certain  quan- 
tity as  soon  as  he  knew  the  proper  pro- 
portion of  the  lime;  and  he  had  thus  the 
advantage  of  being  able  to  work  it  in 
troughs,  in  the  same  manner  as  sulphate 
of  lime.  The  whole  was  well  mixed  to- 
gether and  put  into  sacks ;  by  which 
means  the  masons  had  nothing  to  do  with 
the  mixture  of  the  articles,  (which  is  too 
often  left  to  unprincipled  workmen,)  and 
being  thus  master  of  the  respective  pro- 
portions of  the  puzzolana  and  the  lime, 
he  could  always  be  assured  of  the  solidity 
of  his  cements. 

M.  Dodun's  discovery  may  be  of  some 
use  to  this  country,  as  there  are  in  many 
parts  of  it  large  masses  of  iron  stone,  and 
some  is  found  in  the  vicinity  of  most  coal 
mines. 

It  has  been  long  known  that  iron  ochres 
have  the  same  property  of  forming  puz- 
zolana with  lime,  when  properly  roasted, 
and  this  circumstance  is  mentioned  at 
large  in  Chaptal's  Chemistry.  A  patent 
has  also  been  obtained  in  this  country  for 
the  application  of  iron  pyrites  to  the  same 
purpose,  the  right  to  which  was  purchased 
long  ago  by  Mr  Samuel  Wyatt.  But  the 
novelty  of  M  Dodun's  discovery  is,  that 
poor  iron  stone  is  equally  fit  for  this  use, 
as  the  other  substances  mentioned,  which 
is  of  the  more  importance  as  it  is  very 
plentiful,  and  may  often  be  procured  in 
situations  where  the  others  cannot. 

It  may  not  be  amiss  to  mention  here, 
that  basalt,  treated  in  the  same  manner, 
has  the  same  property  as  the  puzzolana: 
the  whinstone,  of  which  the  ovoidal  pav- 
ing stones  consist  mostly,  is  of  this  kind ; 
and  it  is  found  in  great  abundance  in  these 
countries,  in  different  forms. 

A  substitute  for  puzzolana  may  be  pro- 
cured in  three  ways.  1st,  By  employing 
the  remains  of  extinguished  volcanoes 
which  almost  all  countries  produce.  2dly, 
By  substituting  some  other  volcanic  pro- 
ducts for  puzzolana.  3dly,  By  giving  to 
certain  mineral  substances,  by  calcination, 
all  the  properties  of  these  volcanic  pro- 
ductions. 

We  may  find  a  substitute  for  puzzolana 
in  other  volcanic  products,  such  as  basalt, 
pumice  stones  carefully  pounded,  &c. 

In  1787  M.  Guyton  de  Morveau  sent  to 
M.  de  Cessart  at  Cherbourg,  some  cal- 
cined basalts  from  the  extinguished  vol- 
cano of  Di  evin,  in  the  department  of  the 
Var  and  Loire.  The  latter  proved  by  con- 
clusive experiments,  that  they  might  be 
employed  with  great  advantage  in  build- 
ing under  water. 

The  Dutch  terrass  is  a  kind  of  pumice 
stone  brought  from  Bonn  and  Andernach. 


PUZ 


PUZ 


At  Dordrecht,  at  the  mouths  of  the  Rhine 
and  Meuse,  the  operation  of  pounding  is 
effected. 

But  these  resources  are  local;  and  as 
the  manufacture  of  puzzolana  may  be- 
come general,  we  proceed  to  describe  the 
best  means  of  attaining  it. 

It  would  be  difficult  to  assign  the  pe- 
riod at  which  pounded  bricks  and  the 
earthy  residue  from  the  distillation  of 
aquafortis  were  substituted  for  volcanic 
puzzolana.  Their  use,  however,  has  be- 
come general,  particularly  where  there 
are  no  sea-ports  in  the  vicinity  at  which 
real  puzzolana  can  be  furnished:  even 
in  the  south  of  France  they  prefer  the 
earthy  residue  of  the  distillation  of  aqua- 
fortis to  the  best  puzzolanas  for  coating 
the  inside  of  the  wine  tubs,  which  are  al- 
most all  of  mason  work,  and  for  the  ce- 
ments used  by  individuals  in  hydraulic 
works.  The  earth  employed  in  the  south 
of  France  for  the  decomposition  of  salt- 
petre, by  extracting  the  aquafortis  from 
it,  is  an  ochrey  earth  very  much  charged 
with  iron,  and  more  or  less  reddened  by 
the  oxide  of  this  metal.  When  it  is  want- 
ed for  cement,  it  is  only  necessary  to  beat 
it  up  with  iime,  and  a  proper  quantity  of 
water.  M.  Lepere  relates  some  experi- 
ments made  at  Paris  by  the  engineers  of 
roads  and  bridges,  from  which  it  appears 
that  an  immersion  of  eight  days  was  suffi- 
cient for  aquafortis  cements  to  acquire  a 
hardness  fit  to  resist  a  billet  of  wood 
When  forced  against  it  with  the  whole 
strength  of  a  man;  whereas  the  JtaJian 
puzzolana  required  six  weeks  before  it 
attained  the  same  degree  of  hardness. 

In  general,  the  quality  ot  the  earth  is 
better,  in  proportion  as  it  is  charged  with 
iron. 

This  last  observation  is  equally  appli- 
cable to  pounded  bricks:  in  general, 
they  do  not  make  a  good  cement,  unless 
they  are  well  burnt,  and  made  of  very  fer- 
ruginous earth. 

The  means  suggested  for  making  this 
artificial  puzzolana  are  simple,  and  may- 
be put  in  practice  almost  every  where. 
Balls  should  be  made  of  the  ochrey  earth, 
and  burned  in  a  lime  or  potter's  kiln.  In 
order  to  form  these  balls,  the  earth  must 
be  moistened  with  a  sufficient  quantity  of 
water;  and  when  the  balls  are  made,  they 
should  be  burned  until  they  pass  from  a 
red  to  a  black  colour,  and  the  angles  of 
the  scales  formed  when  they  are  broken 
exhibit  sharp  and  shining  edges* 

M.  Lepere  relates  that  M  Vitalis,  pro- 
fessor of  chemistry,  and  secretary  to  the 
Rouen  Academy,  and  M.  Lamassen,  chief 
engineer  of  the  department  of  the  Lower 


Seine,  have  made  most  excellent  puzzo- 
lana by  the  calcination  of  some  ochrey 
earths  in  the  environs  of  Rouen  :  this  was 
effected  by  burning  the  earth  in  a  com- 
mon furnace  with  alternate  strata  of  com- 
mon charcoal.  This  puzzolana  was  sub- 
jected to  some  trials  on  a  large  scale,  and 
it  was  composed  in  the  following  manner ; 

One  part  and  a  half  of  yellow  calcined 
ochrey  earth. 

One  part  and  three-fourths  of  well 
wsshed  siliceous  sand. 

One  part  and  an  eighth  of  sour  lime. 

Two  parts  of  chip  from  calcareous 
stone  and  sile'x. 

From  these  and  several  other  experi- 
ments (the  proportions  of  which  were  va- 
ried) it  results,  that  the  artificial  puzzo- 
lana constantly  exhibited  the  same  effects 
as  the  best  puzzolana  of  Italy.  M.  Le- 
pere was  an  eye-witness  of  all  these  com- 
parative experiments. 

There  can  be  no  doubt,  therefore,  that 
wherever  there  are  ochrey  earths,  artifi- 
cial puzzolana  may  be  made  with  great 
facility. 

What  is  called  Dutch  terrass  is,  in 
many  respects  similar  to  the  artificial  puz- 
zolana in  question. 

The  ashes,  or  rather  scoriae,  left  when 
coals  are  burnt,  may  also  be  applied  to 
the  same  purpose.  M.  Guyton  caused  a 
trial  to  be  made  at  Cherbourg,  and  it  suc- 
ceeded well. 

M.  Gratian  Lepere,  having  been  intrust- 
ed in  1804  with  constructing-  the  founda- 
tion of  the  new  arsenal  at  Cherbourg,  be- 
gan to  turn  his  attention  to  the  best  me- 
thod of  supplying  the  puzzolana  of  Italy. 
He  knew  that  the  Swedes  had  already 
used  a  very  hard  biack  slate  with  this 
view,  after  being  twice  strongly  calcined 
in  a  lime  kiln. 

M.  Lepere  thought  he  perceived  a  great 
analogy  between  the  Swedish  stone  and 
the  rocks  of  Cherbourg,  particularly  those 
of  port  Bonaparte,  which,  when  dug  into, 
exhibited  a  black  schistus,  hard,  ferrugi- 
nous, and  failing  off  in  scales  of  various 
thickness  :  subsequent  experiments,  how- 
ever, proved  that  the  slaty  schistus  of 
Roule,  in  the  environs  of  Cherbourg,  is 
preferable,  and  that  good  mortar  may  be 
made  with  the  ferruginous  schist  of  Haine- 
ville,  which  is  inferior,  however,  to  the 
two  former. 

After  having  multiplied  and  varied  his 
experiments  in  such  a  manner  as  to  pre- 
sent positive  results,  M.  Lepere,  in  con* 
junction  with  the  committee  of  engineers 
appointed  to  examine  his  experiments, 
draws  the  following  conclusions: 

1st.  That  certain  kinds  of  schist,  when 


PYJR 


PYB 


strongly  calcined  and  pulverized,  form 
an  excellent  mortar  when  mixed  with  sour 
lime 

2dly.  That  in  order  to  give  precisely 
the  same  properties  to  schist  which  are 
possessed  by  puzzolana  and  terrass,  the 
former  must  be  calcined  in  a  reverbe- 
rating, instead  of  a  lime,  furnace.  See 
Cement. 

The  following  cement  for  water  cis- 
terns, aqueducts,  &c  may,  with  propriety, 
be  here  noticed.  Mix  four  parts  of  gray 
clay,  six  of  the  black  oxide  of  manganese, 
and  ninety  of  good  lime-stone  reduced  to 
fine  powder;  then  calcine  the  whole  to  ex- 
pel the  carbonic  acid.  When  this  mixture 
has  been  well  calcined  and  cooled,  it  is  to 
be  worked  into  the  consistence  of  a  soft 
paste,  with  sixty  parts  of  washed  sand. 
If  :i  lump  of  this  cement  be  thrown  into 
water,  it  will  harden  immediately.  Such 
mortar,  however,  may  be  procured  at  a 
still  less  expense,  by  mixing  with  com- 
mon quicklime  a  certain  quantity  of  what 
are  called  the  white  iron  ores,  especially 
such  as  are  poor  in  iron.  These  ores  are 
chiefly  composed  of  manganese  and  car- 
bonate of  lime  or  chalk.  Common  lime 
and  sand  only,  whatever  may  be  the  pro- 
portion of  the  mixture,  will  constantly  be- 
come soft  under  water. 

PYRITES.  Certain  metallic  combina- 
tions, which  contain  a  very  large  propor- 
tion of  sulphur,  are  known  by  this  name. 
They  are  not  indeed  entitled  to  any  parti- 
cular class  not  distinct  from  ores;  yet  their 
abundance  and  other  properties  are  sufii- 
cient  to  justify  their  insertion  in  a  sepa- 
rate article. 

Although  sometimes  pyrites  contains 
more  metal  than  some  ores,  yet  generally 
it  contains  less  metal,  and  a  larger  quan- 
tity of  mineralizing  substances,  sulphur 
and  arsenic,  and  particularly  of  unmetal- 
lic  earth.  The  connexion  of  these  mat- 
ters, is  also  much  stronger  in  pyrites  than 
in  ores,  and  they  are  accordingly  much 
harder  ;  so  that  almost  every  pyrites  can 
strike  sparks  from  steel.  From  this  pro- 
perty of  striking  sparks  from  steel,  they 
have  been  called  pyrites,  which  is  a  Greek 
word  signifying  fire -stone.  Pyrites  was 
formerly  used  for  fire-arms,  as  we  now 
use  flints  ;  hence  it  was  called  carbine 
stone.  It  is  still  named  by  some  marca- 
site.  Perhaps  no  other  kind  of  natural 
body,  has  received  so  many  names.  Per- 
sons curious  to  know  the  other  names 
less  used,  than  those  we  have  mentioned, 
may  find  them  in  Henckel's  Pyritologia 
We  think,  with  that  celebrated  chemist, 
that  the  subject  has  been  perplexed,  by 
this  multiplicity  of  names;  for  before  his 
great  and  excellent  work,  the  notions 


concerning  pyrites,  were  very  confused 
and  inaccurate. 

Pyrites  differs  also  from  ores,  by  its 
forms  and  positions  in  the  earth.  Although 
pyntous  minerals  generally  precede,  ac- 
company, and  follow  veins  of  ores  ;  they 
do  not,  properly  speaking,  themselves 
form  the  oblong  and  continued  masses, 
called  veins,  as  ores  do,  but  they  form 
masses  sometimes  greater,  and  sometimes 
smaller,  but  are  always  distinct  from  each 
other.  Large  quantities  of  them  are  of- 
ten found  unaccompanied  by  ores.  They 
are  formed  in  clays,  chalks,  marls,  mar- 
bles, plasters,  alabasters,  slates,  spars, 
quartz,  granites,  crystals ;  in  a  word,  in. 
all  earths  and  stones.  Many  of  them  are 
also  found  in  pitch-coals,  and  in  other  bi- 
tuminous matters. 

Pyrites  is  also  distinguishable  from 
ores,  by  its  lustre  and  figure,  which  is  al- 
most always  regular  and  uniform,  exter- 
nally or  internally,  or  both.  Some  ores, 
indeed,  like  those  of  lead,  many  ores  of 
silver,  and  some  others,  have  regular 
forms,  and  are  in  some  manner  crystal- 
lized: but  this  regularity  of  form  is  not 
so  universal,  and  so  conspicuous  in  ores 
as  in  pyrites.  The  lustre  of  pyrites  seems 
to  be  caused  by  its  hardness,  and  the  re- 
gularity of  its  form,  by  the  quantity  of 
mineralizing  substances,  which  it  con- 
tains. 

By  all  these  marks  we  may  easily,  and 
without  analyses,  distinguish  pyrites  from 
true  ores.  When  we  see  a  mineral  that 
is  heavy,  possessed  of  metallic  lustre,  and 
of  any  regular  form,  the  mass  of  which 
appears  evidently  to  be  entire,  that  is,  not 
to  have  been  a  fragment  of  another  mass, 
and  which  is  so  hard,  as  to  be  capable  of 
striking  sparks  from  steel,  we  may  be  as- 
sured, that  such  a  mineral  is  a  pyrites, 
and  not  an  ore. 

The  class  of  pyrites  is  very  numerous, 
and  extensive.  They  differ  one  from  ano- 
ther, in  the  nature  and  proportions  of  their 
component  parts,  in  their  forms  and  in 
their  colours.  The  forms  of  these  mine- 
rals are  exceedingly  various.  No  solid, 
regular  or  irregular,  can  easily  be  con- 
ceived, that  is  not  perfectly  imitated,  by- 
some  kind  of  pyrites.  They  are  spheri- 
cal, oval,  cylindrical,  pyramidal,  prisma- 
tic, cubic ;  they  are  solids  with  5,  6,  7, 
8,  9, 10,  and  more  sides.  The  surface  of 
some  is  angular,  and  consists  of  many  ba- 
ses of  small  pyramids,  while  their  sub- 
stance is  composed  of  these  pyramids,  the 
points  of  which  all  unite,  in  the  centre  of 
the  mass. 

Pyritous  minerals  differ  also  in  their 
component  substances.  Some  of  them 
are  called  sulphureous,  martial3  cupre- 


PYR 


PYR 


ous,  arsenical,  as  one  or  other  of  these 
substances  predominates.  We  must  ob- 
serve with  Henckel,  whose  authority  is 
very  great  on  this  subject,  that  in  general 
all  pyrites  are  martial,  as  ferruginous 
earth  is  the  essential,  and  fundamental 
part  of  every  pyrites.  This  earth  is  unit- 
eel  with  an  unmetallio  earth,  with  sulphur 
or  arsenic,  or  with  both  these  matters ; 
in  which  case  the  sulphur  predominates 
over  the  arsenic,  as  Henckel  observes.  He 
considers  these,  as  the  only  essential  prin- 
ciples of  pyrites,  and  believes,  that  all  the 
other  matters,  metallic  or  unmetallic, 
which  are  found  in  it,  are  only  acciden- 
tal ;  among  which  he  even  includes  cop- 
per, although  so  much  of  it  exists  in  some 
kinds  of  pyrites,  that  these  are  treated  as 
ores  of  copper,  and  sometimes  contain 
even  50  lbs.  of  copper  each  quintal.  Many 
other  metals,  even  gold  and  silver,  are 
sometimes  combined  in  pyrites ;  but  these 
are  less  frequent,  and  the  precious  me- 
tals, always  in  very  small  quantities ;  they 
are  therefove  justly  to  be  considered  as 
accidental  to  pyrites.  The  different  sub- 
stances composing  pyrites,  sensibly  affect 
its  colours.  Henckel  distinguishes  them 
in  general,  into  three  colours,  white,  yel- 
lowish, or  a  pale  yellow,  and  yellow.  He 
informs  us,  that  these  three  colours  are 
often  so  blended  one  with  another,  that 
they  cannot  be  easily  distinguished,  unless 
compared  together. 

The  white  pyrites  contain  more  arse- 
nic, and  are  similar  to  cobalt  and  other 
minerals,  abounding  in  arsenic.  The  Ger- 
mans call  them  mispickle,  or  mispilt. 
Iron  and  arsenic  form  the  greatest  part  of 
this  pyrites.  As  arsenic  has  the  property 
of  whitening  copper,  some  pyritous  mine- 
rals almost  white,  like  that  of  Chemnitz 
in  Misnia,  are  found  to  contain  40  lbs.  of 
copper  per  quintal,  and  are  so  much  whit- 
ened by  the  arsenic,  that  they  are  very 
like  white  pyrites.  But  Henckel  observes, 
that  these  pyritous  matters  are  very  rare, 
and  are  never  so  white,  as  the  true  white 
pyrites,  which  is  only  ferruginous  and 
arsenical. 

Yellowish  pyrites  is  chiefly  composed 
of  sulphur  and  iron.  Very  little  copper 
and  arsenic  are  mixed  with  any  pyrites 
of  this  colour,  and  most  of  them  contain 
none  of  these  two  metallic  substances. 
This  is  the  most  common  kind  of  pyrites: 
it  is  to  be  found  almost  every  where.  Its 
forms  are  chiefly  round,  spherical,  oval, 
flattened,  cylindrical ;  and  it  is  composed 
internally,  of  needles  or  radii,  which 
unite  in  the  centre,  or  in  the  axis  of  the 
solid. 

Yellow  pyrites,  receives  its  colour  from 
the  copper  and  sulphur,  which  enter  into 


its  composition.  Its  colour,  however,  is 
inclined  to  a  green,  but  is  sufficiently  yel- 
low, to  distinguish  it  from  the  other  two 
kinds  of  pyrites,  particularly  when  they 
are  compared  together.  To  make  this 
comparison  well,  the  pyrites  must  be 
broken,  and  the  internal  surfaces  must  be 
placed  near  each  other.  The  reason  of 
this  precaution  is,  that  the  colour  of 
minerals  is  altered,  by  exposure  to  the 
air. 

Persons  accustomed  to  these  minerals, 
can  easily  distinguish  them.  The  chief 
difficulty  is,  to  distinguish  white  pyrites 
from  cobalt  and  other  minerals,  which 
also  contain  some  copper,  and  much  ar- 
senic. 

Hence  then  we  see,  that  arsenic  is  the 
cause  of  whiteness  in  pyrites,  and  is  con- 
tained in  every  pyrites  of  that  colour  ; 
that  copper  is  the  principal  cause  of  the 
yellow  colour  of  pyrites,  and  that  every 
pyrites  which  is  evidently  yellow,  con- 
tains copper  ;  that  sulphur  and  iron,  pro- 
duce a  pale  yellow  colour,  which  is  also 
produced  by  copper  and  arsenic  ;  hence 
some  difficulty  may  arise,  in  distinguish- 
ing pyrites  from  its  colours.  We  may 
also  observe,  that  sulphur  and  arsenic, 
without  any  other  substance,  form  a  yel- 
low compound,  as  we  see  from  the  exam- 
ple of  orpiment.  or  yellow  arsenic.  Thus, 
although  the  colours  of  the  pyrites,  ena- 
ble us  to  distinguish  its  different  kinds, 
and  to  know  their  nature  at  first  sight, 
particularly  when  we  have  been  accus- 
tomed to  observe  them  ;  yet  we  cannot 
be  entirely  certain,  concerning  the  true 
nature  of  these  minerals,  and  even  of  all 
minerals  in  genera!,  that  is,  to  know  pre- 
cisely the  kinds  and  proportions  of  their 
component  substances,  but  by  chemical 
analyses  and  decomposition. 

Beside  the  above-mentioned  matters, 
which  compose  pyrites,  it  also  contains  a 
considerable  quantity  of  unmetallic  earth, 
that  is,  an  earth  which  cannot  by  any  pro- 
cess be  reduced  to  metal.  Henckel,  Cra- 
mer, and  all  those  who  have  examined 
this  matter,  mention  this  earth,  and  prove 
its  existence. 

We  ought  to  observe,  that  this  earth 
is  combined,  with  the  other  principles  of 
the  pyrites,  and  not  merely  interposed  be- 
tween its  parts.  It  must,  therefore,  be 
distinguished  from  earthy  and  stony  mat- 
ters, mixed  accidentally  with  pyrites,  and 
which  do  uot  make  a  part  of  the  pyrites, 
since  they  may  be  separated  by  mechani- 
cal means,  and  without  decomposing  that 
mineral :  but  the  earth  of  which  we  now 
treat,  is  intimately  united,  with  the  other 
constituent  parts  of  the  pyrites,  is  even  a 
constituent  part  of  the  pyrites,  and  essen- 


PYR 


PYR 


ual  to  the  existence  of  this  mineral,  and 
cannot  be  separated,  but  by  a  total  de- 
composition of  it. 

According-  to  Hcnckcl,  this  unmetallic 
earth  abounds  much  in  the  white  pyrites, 
since  he  found  from  the  analyses,  which 
he  made,  that  the  iron,  which  is  the  only 
metal  existing-  in  these  pyrites,  is  only 
about  one -twenty-sixth  part  of  the  fixed 
substance,  that  remains  after  the  arsenic 
has  been  expelled,  by  torrefaction  or  sub- 
limation. 

A  much  larger  quantity  of  iron  is  in 
the  paie  yellow  pyrites,  according-  to 
Henckel.  The  proportion  of  iron,  is  ge- 
nerally about  twelve  pounds,  to  a  quintal 
of  pyrites,  and  sometimes  fifty  or  sixty 
pounds :  this  is  therefore  called  martial 
pyrites.  It  contains  about  one-fourth  of 
its  weight  of  sulphur,  and  the  rest  is  un- 
metailic  earth. 

The  quantity  of  unmetallic  earth,  con- 
tained in  the  yellow  or  cupreous  pyrites, 
which  are  also  martial,  since,  as  we  have 
observed,  iron  is  an  essential  part  of  eve- 
ry pyrites,  has  not  yet  been  determined. 
They  probably  contain  some  of  that 
earth,  though  perhaps  less  of  it,  than  the 
others. 

The  nature  of  this  unmetallic  earth  of 
pyrites  has  not  been  well  examined. 
Henckel  thinks,  that  it  is  an  earth  dis- 
posed already  by  nature,  to  metallization, 
but  not  sufficiently  elaborated,  to  be  con- 
sidered as  a  metallic  earth.  See  the  ar- 
ticles Metals  and  Metallization. 
This  opinion  is  not  improbable ;  but  as 
alum  may  be  obtained  from  many  pyrites, 
may  we  not  suspect,  that  this  unmetallic 
earth,  is  of  the  nature  of  alumine  ?  See 
Alum  and  Earths,  Alumine.  Per- 
haps also  this  earth  is  different,  in  differ- 
ent kinds  of  pyrites.  The  subject  deserves 
to  be  well  examined. 

Although  pyrites  is  not  so  valuable  as 
true  ores,  because  in  general  it  contains 
less  metal,  and  but  exceedingly  little,  of 
the  precious  metals ;  and  because  its  me- 
tallic contents,  are  so  difficult  to  be  ex- 
tracted, that,  excepting  cupreous  pyrites, 
which  is  called  pyritous  copper  ore,  it  is 
not  worked  for  the  sake  of  the  contained 
metal;  yet  it  is  applied  to  other  purposes, 
and  furnishes  us  with  many  useful  sub- 
stances ;  for,  from  it,  we  obtain  all  our 
green  and  blue  vitriols,  much  sulphur, 
arsenic,  alum,  and  orpimcnt.  See  the 
principal  processes,  by  which  these  sub- 
stances are  extracted  from  pyrites,  under 
Ores,  and  the  respective  articles. 

As  every  pyrites  contains  iron,  and  most 
of  them  contain  also  sulphur  ;  as  the  py- 
rites most  frequently  found,  contains  on- 
ly these  two  substances,  with  the  unme- 


tallic earth  ;  and  as  iron  and  sulphur  have 
a  singular  action  upon  each  other,>when 
they  are  well  mixed  together,  and  moist- 
ened  ;  hence  many  kinds  of  pyrites,  par- 
ticularly those  which  contain  only  the 
principles  now  mentioned,  sustain  a  sin- 
gular alteration,  and  even  a  total  decom- 
position, when  exposed  during  a  certain 
time,  to  the  combined  action  of  air  and 
water.  The  moisture  gradually  pene- 
trates them,  divides,  and  attenuates  their 
parts;  and  the  sulphur  is  acidified,  attacks 
the  martial  earth,  and  also  the  unmetal- 
lic earth,  and  forms,  with  the  fixed  prin- 
ciples of  the  pyrites,  different  salts  ;  so 
that  a  pyrites,  which  was  once  a  shining, 
compact,  very  hard  mineral,  becomes  in  a 
certain  time,  a  grayish,  saline,  powdery 
mass,  the  taste  of  which  is  saline,  austere, 
and  styptic. 

Lastly,  if  this  mass  be  lixiviated  with 
water,  crystals  of  suiphat  of  iron,  and 
sometimes  of  alum,  according  to  the  na- 
ture of  the  pyrites  employed,  may  be 
obtained  by  evaporation,  and  crystalliza- 
tion 

This  alteration  and  spontaneous  decom- 
position of  pyrites  is  called  efflorescence 
and  vitriolization ;  because  the  pyrites  be- 
come covered  with  a  saline  powder,  and 
because  vitriol  is  always  formed.  This  vi- 
triolization is  more  or  less  quickly  accom- 
plished in  pyrites  according  to  its  nature. 
It  is  a  kind  of  fermentation  excited  by 
moisture  amongst  the  constituent  parts  of 
these  minerals ;  and  it  is  so  violent  in 
those  which  are  most  disposed  to  it,  that 
is,  in  the  pale -yellow  pyrites,  which  con- 
tain chiefly  sulphur  and  iron,  that  when 
the  quantity  of  these  is  considerable,  not 
only  a  sulphureous  vapour  and  heat  may 
be  perceived,  but  also  the  whole  kindles 
and  burns  intensely.  The  same  pheno- 
mena are  observable,  and  the  same  results 
are  formed,  by  mixing  well  together  and 
moistening  a  large  quantity  of  filings  of 
iron  and  powdered  sulphur;  which  expe- 
riment Lemery  has  made,  to  explain  the 
causes  of  subterranean  fires  and  volca- 
noes. 

We  cannot  doubt,  that,  as  the  earth 
contains  very  large  masses  of  pyrites  of 
this  kind,  they  must  undergo  the  same 
changes  when  air  and  moisture  penetrate 
the  cavities  containing  them  ;  and  the  best 
natural  philosophers  agree,  that  very  pro- 
bably, this  surprising  decomposition  of 
pyrites  is  the  cause  of  subterranean  fires, 
of  volcanoes,  and  of  mineral  waters,  sul- 
phuric, aluminous,  sulphureous,  hot  and 
cold. 

No  other  pyrites  is  subject  to  this  spon- 
taneous decomposition,  when  exposed  to 
humid  air,  but  that  which  is  both  martial 


QUA 


QUE 


and  sulphureous,  that  is,  the  pale-yellow 
pyrites.  The  arsenical  pyrites,  or  that 
which  contains  little  or  no  sulphur,  is  not 
changed  hy  exposure  to  air.  This  latter 
kind  is  harder,  heavier,  and  more  com- 
pact than  the  former.  The  pyrites  which 
is  angular  and  regularly  shaped,  is  chief- 
ly of  this  kind.  Wallerius,  in  his  Minera- 
logy, proposes  to  distinguish  this  kind  of 
pyrites  by  the  name  of  marcasite.  Wren 
cut,  it  may  be  polished  so  well  as  to  give 
a  lustre  almost  equal  to  that  of  diamonds  : 
but  without  refracting  or  decomposing 
the  light;  for  it  is  perfectly  opake.  it 
was  employed  some  yeai\s  ago  in  the  ma- 
nufacture of  toys,  as  of  buckles,  neck- 
laces, &c,  and  is  called  in  commerce 
marcasite.  See  Waters,  Mineral,  and 
Ores. 

PYROLIGNEOUS  ACID— In  the  de- 
structive distillation  of  any  kind  of  wood, 
an  acid  is  obtained,  which  was  formerly 
called  acid  spirit  of  wood,  and  since  pyro- 
ligneous  acid  In  distilling  cork,  how- 
ever, it  appeared  to  Fourcroy  and  Vau- 
quelin,  that  the  acid  obtained  resembled 
the  acetous  ;  and  on  pursuing  the  investi- 
gation they  ascertained,  both  analytically 
and  synthetically,  that  the  pyroligneous 
acid  is  nothing  moi  e  than  the  acetous  con- 
taminated with  an  empyreumatic  oil  pro- 
duced from  the  wood. 

This  acid  is  obtained  in  large  quanti- 
ties by  the  distillation  of  wood  in  cast  iron 
cylinders,  which  is  done  for  the  purpose 
of  charring  the  wood  for  the  mancfacture 


of  gunpowder.  It  is  conveyed  by  means 
of  pipes  into  a  suitable  receiver,  and  is 
used  largely  in  some  mann factories  in 
preparing  the  iron  liquor.  Dr.  Bollman 
recommends  it  as  a  substitute  lor  vine- 
gar. 

PYROTECHNICS.— The  art  of  making 
fire-works.  In  this  art  the  chief  objects 
are  to  produce  a  st  earn  of  fire,  or  an  ex- 
plosion. Gunpowder  included  in  a  strong 
paper  implement  affords  the  latter  effect ; 
the  fiery  stream  is  produced  by  mixing 
the  ingredients  of  gunpowder  together  in 
different  proportions,  and  pulverizing 
them  without  wetting.  These  burn  more 
slowly  than  grained  gunpowder.  A  sky- 
rocket is  formed  by  ramming  this  compo- 
j  sition  into  a  paper  tube,  to  which  an  arrow 
or  tail  is  connected.  The  explosive  stream 
gives  the  rocket  a  progressive  motion  by 
its  reaction.  Rockets  are  sometimes  used 
in  war;  but  as  they  are  most  commonly 
exhibited  for  mere  amusement,  it  is  usual 
to  include  gunpowder  in  the  head  of  the 
rocket  with  bails  of  a  still  more  slowly 
burning  compound,  with  additions  to  vary 
the  colour  they  exhibit  at  the  instant  of 
the  explosion,  and  for  a  few  seconds  after- 
ward. 

Lights  are  also  made  for  signals  and 
station-marks.  But  as  all  these  objects 
are  in  some  measure  remote  from  the  ex- 
planation of  scientific  chemistry,  the  rea- 
der is  referred  to  treatises  written  ex- 
pressly on  this  art.    See  Rocket. 


QtJARTATION,  a  method  of  separa- 
ting gold  from  silver.  See  Assaying, 
and  Gold. 

QUARTZ,  a  siliceous  stone,  compre- 
hending several  sub-species,  as  crystal- 
lized quartz,  or  rock  crystal,  fibrous',  gra- 
nular, and  compact  quartz. 

Several  of  the  varieties  of  crystallized 
quartz  are  used  as  seal  stones  and  orna- 
ments of  various  kinds,  on  account  of 
their  hardness,  the  exquisite  polish  that 
they  are  capable  of  receiving,  and  the 
pleasing  tone  of  their  colours.  The  most 
perfectly  transparent  and  colourless  is 
called  by  the  lapidaries  rock  crystal;  and  be- 
sides being  applied  to  various  purposes  of 
ornament,  it  is  cut  into  spectacle  glasses, 
which,  from  their  hardness,  are  not  so 
liable  to  be*  scratched  as  those  which  are 
made  of  flint  glass.  The  reddish  purple, 
or  violet  coloured  variety,  is  culled  ame- 


thyst, and  is  occasionally  ranked  among 
the  gems  s  it  must  not,  however,  be  con- 
founded with  the  oriental  amethyst,  which 
is  a  true  gem,  being  a  variety  of  corun- 
dum. The  pearl  gray,  or  pale  blue  va- 
riety, is  called  false,  or  water  sapphire. 
The  yellow  and  smoke  coloured  varieties 
are  called  false  topaz.  The  green  varie- 
ties are  not  unfrequently  mistaken  for 
chrysolite. 

The  granular  quartz  is  used  largely  in 
the  manufacture  of  china  ware ;  it  it  first 
calcined,  which  renders  it  opake  and  brit- 
tle, and  afterwards  pulverized.  When 
flint  stone,  which  is  more  generally  used, 
cannot  be  procured,  the  granular  quartz 
is  next  preferred.  Our  country  abounds 
with  all  the  varieties  of  siliceous  stones, 
suitable  either  for  flint  making,  glass 
making,  or  pottery. 

QUERCITRON,  or  Black-oak  6ari.— 


QUI 


QUI 


This  bark  is  used  largely  in  tanning,  dye- 
ing, &c,  and  has  become  a  considerable 
article  of  exportation. 

According  to  Dr  Bancroft,  the  querci- 
tron bark  may  be  advantageously  substi- 
tuted for  weld  in  the  printing  of  linens  ; 
but  it  must  be  only  simply  infused  in  warm 
water,  and  onlv  one  part  employed,  in- 
stead of  ten  of  weld. 

To  dye  wool  yellow,  Dr.  Bancroft  ad- 
vises, that  a  solution  of  tin  and  alum 
should  be  put  into  the  bath  with  the 
quercitron.  Silk  ought  to  be  treated  in 
the  same  manner  as  with  weld :  if  a  veay 
bright  yellow  be  required,  it  must  be  pre- 
pared with  a  solution  of  tin. 

It  appears  from  some  information,  for 
which  Berthollet  was  indebted  to  Mr. 
Brown,  that  many  manufacturers  of  print- 
ed linens  in  England,  at  present  prefer 
this  bark  to  weld,  because  it  is  considera- 
bly cheaper,  and  the  ground  whitens  more 
easily.  Some  find  it  advantageous  to  mix 
a  certain  proportion  of  decoction  of  weld 
with  the  quercitron  bath,  which  should 
be  exposed  to  only  a  gentle  heat.  Mr. 
D'Ambourney  asserts,  that,  to  obtain  the 
advantages  set  forth  by  Dr.  Bancroft,  the 
wool  must  be  first  prepared  with  solution 
of  tin,  and  then  his  process  followed.  See 
Dyeing. 

QUICKLIME.  See  Earths, art.  Lime. 

QUICKSILVER.    Sec  Mercury. 

QUILLS.— Quills  are  the  large  feathers 
taken  out  of  the  end  of  the  wings  of  geese, 
ostriches,  crows,  &c.  They  are  denomi- 
nated from  the  order  in  which  they  are 
fixed  in  the  wing ;  the  second  and  third 
quills  being  the  best  for  writing,  as  they 
have  the  largest  and  roundest  barrels. 
Crow  quills  are  chiefly  used  foi  drawing 

Large  quantities  of  quills  have  been 
yearly  imported  from  Germany  and  Hol- 
land. 

The  goodness  of  quills  is  judged  by  the 
size  of  the  barrels,  but  particularly  by  the 
weight ;  hence  the  denomination  of  quills 
of  fourteen,  fifteen,  &c.  loths:  viz.  the 
thousand  consisting  of  twelve  hundred 
quills,  weighing  fourteen,  fifteen,  &c. 


lolhs.    The  loth  is  a  German  weight, 

weighing  something  more  than  an  ounce. 
Particular  attention  should  be  paid  on 
purchasing  quills,  that  they  may  not  be 
left  handed,  that  is,  not  out  of  the  left 

wing. 

To  render  quills  firm  as  well  as  elastic, 
various  modes  have  been  contrived.  The 
process  is  called  clarification.  The  most 
simple  means  is  to  thrust  the  barrel  into 
hot  sand  for  a  few  minutes  ;  afterwards  it 
is  pressed  almost  flat,  by  means  of  a  pen- 
knife, and  then  rendered  round  between 
the  fingers,  by  the  assistance  of  a  piece 
of  leather,  or  woollen  cloth;  with  which 
their  exernal  roughness  may  be  easily  re- 
moved by  friction.  If,  however,  a  consi- 
derable number  of  quills  is  to  be  harden- 
ed, it  will  be  advisable  to  set  a  vessel, 
containing  a  little  water  and  alum,  over 
the  fire ;  as  soon  as  the  liquor  begins  to 
boil,  the  barrels  only  must  be  immersed 
for  a  minute,  after  which  they  may  be 
suspended  to  dry.  Good  pens  constitute 
an  article  of  indispensible  necessity  in  all 
departments  of  trade,  commerce  and  lite- 
rature, See.  Hence,  it  becomes  an  useful, 
if  not  important  object,  to  be  able  to  cut 
them  according  to  the  most  approved 
rules.  The  reader,  who  is  desirous  of  in- 
formation on  this  head,  may  examine  Mr, 
Wilkes's  small  tract,  entitled,  7  he  Art  of 
Making  Pens  scientifically,  &c,  in  which 
piain  directions  are  given  to  that  effect, 
together  with  appropriate  instructions  for 
the  management  of  the  quill,  pen-knife, 
hone,  strop,  and  other  other  articles,  con- 
nected with  the  art  of  pen-making. 

QUINTESSENCE  —As  the  essence  of 
any  medicinal  substance,  or  that  in  which 
its  chief  virtue  resided,  was  supposed  by 
the  old  chemists  to  be  obtainable  in  a  con- 
densed form  by  distillation  ;  so  they  ima- 
gined, that  it  was  still  farther  condensed 
and  purified  by  subsequent  distillations. 
Hence  they  used  the  term  quintessence, 
or  result  of  the  fifth  distillation,  to  denote 
any  thing  thus  brought  to  its  highest  de- 
gree of  purity  as  they  conceived.  It  is 
now  obsolete. 


RAI  RAI 

R, 


RACK.  See  Arrack,  Distilla- 
tion, &c. 

RADICAL. — That  which  is  considered 
as  constituting  the  distinguishing  part  of 
an  acid  by  its  union  with  the  acidifying 
principle  or  oxigen,  which  is  common  to 
all  acids.  Thus  sulphur  is  the  radical  of 
the  sulphuric  and  sulphurous  acids.  It  is 
sometimes  called  the  base  of  the  acid,  but 
base  is  a  term  of  more  extensive  applica- 
tion. 

RADICAL  VINEGAR.  See  Acetic 
Acid. 

RAG-STONE. — The  colour  of  this 
stone  is  gray  ;  its  texture  obscurely  lamel- 
lar, but  the  laminae  consist  of  a  congeries 
of  grains  of  a  quartz  appearance,  coarse 
and  rough.  Its  specific  gravity  is  2.779. 
It  effervesces  with  acids,  and  gives  fire 
with  steel.  It  is  used  as  a  whetstone,  fre- 
quently without  the  application  either  of 
water  or  oil. 

Whence  it  comes  to  us  we  know  not, 
but  its  appearance  resembles  the  pumice 
in  every  respect  except  its  density.  Its 
component  parts  in  Kirwan's  tables,  are 
70  silex,  5  alumine,  25  carbonat  of  lime, 
and  5  iron,  as  he  thinks.  This  differs 
from  the  Rowley  Rag,  which  see. 

RAGS,  Bleaching  of.  See  Paper- 
making. 

RAILWAY. — On  the  14th  of  August, 
1799,  a  party  deputed  from  the  commit- 
tee for  conducting  the  concerns  of  the 
Grand  Junction  Canal,  with  other  gentle- 
men, attended  at  Mr.  Joseph  Wilkes  col- 
liery, at  Measham,  in  Derbyshire,  (Eng- 
land) for  the  purpose  of  obtaining  occular 
and  satisfactory  proof  of  the  utility  of  the 
iron  railways,  previous  to  that  company 
adopting  them  (which  they  have  now 
done)  in  lieu  of  some  portion  of  their  line 
of  canal.  The  result  of  the  experiments 
was  nearly  thus  :  one  horse,  of  the  value 
of  20/.  on  a  declivity  of  an  iron  road  five- 
sixteenths  of  an  inch  at  a  yard,  drew 
twenty-one  carriages  or  waggons,  laden 
with  coals  and  timber,  amounting,  in  the 
whole,  to  thirty-five  tons,  overcoming  the 
vis  inertia,  repeatedly,  with  great  ease. 
The  same  horse,  up  this  acclivity,  drew 
five  tons  with  ease  ;  he  also  drew  up  the 
road,  where  the  acclivity  was  1  3-4  of  an 
inch  at  a  yard,  three  tons.  But  on  this 
declivity  it  is  necessary  to  slipper  or  lock 
the  wheels,  the  horse  not  being  able  to  re- 
sist the  increased  momentum  of  more  than 
three  or  four  tons. 
VOL.  II. 


The  same  gentlemen  proceeded  the 
next  day  to  another  colliery  in  Notting- 
hamshire, where  one  horse,  value  30/., 
drew,  on  a  road  of  the  same  construction, 
where  the  declivity  was  one-third  of  an 
inch  at  a  yard,  twenty-one  waggons,  of 
five  hundred  weight  each,  which,  with 
their  loading  of  coals,  amounted  to  forty- 
three  tons,  eight  hundred  weight;  the 
same  horse  drew  seven  tons  up  the  road. 
It  must  be  observed,  that  in  both  the  fore- 
going statements,  the  hundred  weight  is 
120  lb.  On  this  road  the  rails  are  three 
feet  long  each,  33  lb.  weight,  and  calcu- 
lated to  carry  two  tons  on  each  waggon, 
laid  four  feet  two  inches  wide,  on  stone 
or  wood  sleepers,  placed  on  a  bed  of  sleek 
so  as  to  fix  it  solid  and  firm.  The  ex- 
pense of  completing  one  mile  of  such  a 
road,  where  materials  of  all  descriptions 
lie  convenient,  and  where  the  land  lies  to- 
lerably favourable  for  the  descent,  will  be 
about  900/.  or  1000/.  sterling  per  mile,  sin- 
gle road,  fenced,  &c.  exclusive  of  bridges, 
culverts,  or  any  extra  expense  in  deep  cut- 
ting, or  high  embankments.  Rails  are 
made  from  twenty  to  forty  pound  per  yard, 
agreeable  to  the  weight  they  have  to  bear- 
By  the  introduction  of  iron  railways, 
constructed  on  the  best  plan,  canals  may 
extend  their  useful  influence  in  enriching 
and  improving  the  country  to  the  distance 
of  ten  or  twenty  miles  on  either  side  of 
them,  into  high  mountainous  countries, 
where  canals  are  almost  impracticable  : 
instance  the  railway  of  the  Peak  Forest, 
in  Derbyshire,  which  joins  the  Ashton  ca- 
nal, the  road  from  Denbigh  to  near  the 
town  of  Derby,  and  a  great  many  others. 
In  numberless  cases,  near  large  towns, 
they  would,  no  doubt,  be  of  the  greatest 
utility ;  as  for  Paddington  and  the  Thames, 
to  diff  erent  parts  of  the  metropolis,  to  con- 
vey merchandize  to  and  from,  as  well  as 
speedily  and  easily  take  off  nuisances 
from  the  town,  cause  less  wear  to  the 
streets,  and  prevent  many  disagreeable 
consequences  arising  from  the  great  num- 
ber of  heavy  burthened  carriages  crowd- 
ing together. 

In  a  great  many  instances  it  will  occur, 
where  a  railway,  either  connected  with  a 
canal  or  not,  will  be  the  mode  of  a  cheap- 
er conveyance  than  water  would  be.  It 
clearly  appears,  in  the  case  of  the  Ashby 
canal,  that  their  railway,  which  is  now 
executing,  and  a  double  one,  will  cost 
two-thirds  less  than  a  canal  would  have 

r  r 


EAI 


RAI 


done  in  the  district  of  their  railway,  where 
the  ground  for  a  canal  is  unfavourable, 
and  furnish  the  article  of  lime,  which  ii  is 
principally  intended  to  convey,  at  two- 
iifths  less  than  a  canal  would  have  done, 
though  it  is  an  ascent  for  some  miles  on 
the  road ;  so  it  is  with  the  Peak  Forest, 
Derby,  &c.  In  short,  wherever  the  quan- 
tity of  goo«lss  10  be  conveyed  on  a  railway, 
having  a  descent  of  not  more  than  half  an 
inch  in  a  yard,  amounts  to  two-thirds  of 
the  weight,  as  downgate  loading,  it  is  a 
doubt  if  it  will  not,  in  that  case,  be  a 
cheaper  conveyance  than  a  canal :  if  dis- 
patch is  necessary,  a  railway  is  more  cer- 
tain than  a  canal,  being  far  more  easily  re- 
paired ;  neither  does  frost  or  dry  seasons 
affect  the  trade  thereon. 

Iron  railways  have  been  used  for  some 
years  in  Shropshire,  and  other  places  ;  but 
for  want  of  proper  system  in  the  forming 
and  laying  of  such  roads,  they  have  been 
found  of  little  or  no  more  service  than 
wood  railways,  which  from  the  late  im- 
provements in  iron  roads,  are  now  in  dis- 
repute. 

The  leading  principles  of  iron  roads 
are,  that  the  ground  should  be  formed 
true,  making  a  perfect  inclined  plane, 
made  dry  by  cutting-  back-drains,  sough- 
ing, &c.  Sleepers  of  stone,  rather  than 
wood,  on  which  the  rails  rest,  and  which 
should  be  firmly  fixed  on  a  bed  of  stone, 
beat  small,  the  horse-path  filled  with  good 
small  hard  materials,  rails  three  feet  long 
each,  weighing  thirty-three  pound,  to  car- 
ry two  tons,  and  laid  not  less  than  four 
feet  wide. 

Iron  roads,  constructed  on  this  plan, 
which  is  yet  far  short  of  the  perfection 
they  will  arrive  at,  for  the  carriage  of 
heavy  goods  to  and  from  large  commer- 
cial towns,  in  conjunction  with  canals,  will 
evidently  be  of  great  national  advantage ; 
and  if  the  turnpike  roads  were  made  on 
the  concave  system,  the  first  principle  of 
which  is  to  have  a  perfect  inclined  plane, 
a  considerable  revenue  might  be  derived 
by  government  therefrom,  without  a  tax 
upon  the  public.  Repairs  would  be  very 
trifling,  owing  to  water  becoming  the  prin- 
cipal repairing  agent ;  the  traveller  expe- 
dited from  the  smoothness  of  the  road, 
and  more  secure  from  accident ;  the  com- 
merce of  the  country  speedily  conveyed 
from  one  point  to  another,  and  the  farmer 
would  be  benefitted  by  the  advantage  of 
a  rich  wash,  which  might  be  easily  con- 
ducted from  the  roads,  over  his  fields, 
perhaps  in  many  cases  equivalent  to  the 
maintenance  of  the  road. 

The  following  account  of  the  Penrhyn 
railway  may  be  acceptable  to  many  of  our 


readers.  The  rail  hitherto  made  use  of 
in  most  railways  is  a  flat  one,  three  fee*, 
in  length,  with  a  nb  on  one  edge,  to  give 
it  strength,  and  to  prevent  the  wheels 
(which  have  a  flat  rim)  from  running  off. 
Observing  that  these  rails  were  frequent- 
ly obstructed  by  stones  and  dirt  lodged 
upon  them  ;  that  they  were  obliged  to  be 
fastened  to  single  stones  or  blocks  on  ac- 
count of  their  not  rising  sufficient!}  high 
above  the  sills,  to  admit  of  gravelling  the 
horse-path;  that  the  sharp  rib  standing 
up  was  dangerous  for  the  horses  ;  that  the 
strength  of  the  rail  was  applied  the  wrong 
way;  and  that  less  surface  wouid  create 
less  friction;  led  Mr.  Wyatt  to  consider, 
if  some  better  form  of  rail  could  not  be 
applied  j  the  oval  presented  itself  as  the 
best  adapted  to  correct  all  the  faults  of 
the  fiat  rail,  and  he  had  the  satisfaction  to 
say  that  it  has  completely  answered  the 
purpose  in  a  railway  lately  executed  for 
Lord  Penrhyn,  from  his  lordship's  slate- 
quarries,  in  Carnarvonshire,  to  Port  Pen- 
rhyn. The  wheel  made  use  of  on  this 
rail  has  a  concave  rim,  so  contrived  in  its 
form,  and  the  wheels  so  fixed  upon  their 
axis,  as  to  move  with  the  greatest  facility 
in  the  sharpest,  curves  that  can  be  re- 
quired. It  is  plain,  by  inspecting  this 
rail,  that  no  dirt  can  lodge  upon  it ;  that 
it  must  be  stronger  than  any  other  form 
of  the  same  Weight,  to  resist  both  the  per- 
pendicular and  lateral  pressure;  that  it 
must  occasion  very  little  friction  ;  that  it 
presents  no  danger  to  the  horse ;  and  that 
it  may  be  placed  upon  the  siils,  so  as  to 
admit  of  a  sufficient  quantity  of  gravel  to 
cover  them.  These  advantages  have  so 
forcibly  struck  all  those  who  have  seen 
and  examined  this  road,  that  he  has  been 
induced  to  lay  it  before  the  public  through 
the  medium  of  the  Repertory  of  Arts  and 
Manufactures. 

The  Penrhyn  railway  is  six  miles  and  a 
quarter  in  length,  divided  into  five  stages. 
It  has  three-eighths  of  an  inch  fall  in  a 
vard,  with  three  inclines ;  was  begun  in 
October  1800,  and  finished  in  July  1801. 

On  this  railway  two  horses  will  draw 
twenty-four  waggons  one  stage  six  times 
a  day,  and  carry  twenty-four  tons  each 
journey,  which  is  144  tons  per  day.  This 
quantity  used  to  employ  144  carts  and 
400  horses:  so  that  ten  horses  will,  by 
means  of  this  railway,  do  the  work  of 
four  hundred. 

Mr.  I'essenden  remarks  that,  the  pre- 
ceding he  hopes  will  meet  with  particular 
investigation  from  gentlemen  who  propose 
to  embark  property  in  cutting  canals,  and 
making  locks  to  falls  in  our  navigable  ri- 
vers.   If  the  advantages  attending  these 


RAI 


RAI 


railways  are  equ.il  to  what  is  here  repre- 
sented, they  ought,  in  most  cases,  to  su- 
percede canal  and  lock  navigation. 

Two  horses  would,  on  a  conical  iron 
road,  convey  a  mail  coach  more  than 
eight  miles  per  hour  as  easy  as  the  pre- 
sent mails  are  conveyed  six  miles  per  hour 
by  four  horses.  The  conveyance  would 
be  so  easy,  that  gentlemen  might  read 
•nearly  as  well  as  on  board  a  ship.  The 
even  and  compact  manner  in  which  this 
road  would  be  laid,  would  render  it  the 
Safest  of  all  others,  with  the  additional  ad- 
vantage of  using  wheels  of  any  diameter. 
As  this  road  might  be  kept  constantly 
moist,  it  would  have  a  singular  advantage 
over  oilier  iron  roads,  in  keeping  the  me- 
tal perfectly  cool,  and  consequently  less 
friction  and  wear.  It  has  ever  been  an  ob- 
ject in  the  projection  of  canals,  to  bring 
them  as  near  towns  as  possible,  when, 
after  all,  a  cartage,  or  removal,  must  take 
place.  In  bringing  a  canal  near  a  large 
town  the  difficulties  and  inconveniences 
are  very  great ;  valuable  property  is 
wasted,  communication  (which  is  very  es- 
sential) is  cut  off,  the  situation  for  the  bu- 
siness is  limited,  no  further  extension  can 
take  place  ;  even  this  may  be  in  a  situa- 
tion where  there  is  an  embankment,  of 
course  inconvenient  to  load  in  and  out ;  or 
if  deep  cuttings,  the  wharves  are  then 
expensive  in  excavating.  This  railway 
would  waste  valuable  land  near  a  large 
town  in  a  trifling  comparative  degree  to  a 
canal,  communication  would  be  free,  on 
and  over  every  part  of  the  same ;  nor 
would  there  be  any  particular  limited  si- 
tuation for  wharves  or  warehouses  :  hence 
large  towns  would  derive  benefit  in  every  ! 
part  near  which  the  road  would  be  ex-  j 
tended,  carriages  would  not  be  liable  to  I 
break  down,  nor  would  the  wear  of  tires,  J 
or  any  part,  be  put  out  of  order  by  vio- 
lent shocks.  The  easy  repairs  of  car- 
riages on  such  a  road  will  certainly  bear 
no  comparison  to  those  on  common  roads. 
The  iron  railways  in  use,  wherever  they 
are  upon,  and  cross  a  turnpike  road,  are 
inconvenient;  these,  on  the  contrary, form 
not  the  least  impediment, 

About  the  year  1768,  a  remedy  was 
contrived  for  the  principal  objection  to 
cast  iron  railways :  namely,  the  making 
use  of  several  small  «  aggons  linked  to- 
gether, instead  of  one  large  one;  thus  dif- 
fusing ihe  weight  over  a  greater  surface 
of  the  road,  and  consequently  throwing 
less  stress  on  any  one  part  of  it.  Soon 
after  the  year  1797",  they  began  to  be  con- 
structed as  branches  to  canals  :  since  that 
period  they  have  rapidly  increased,  and 
their  great  utility  is  now  unquestionably 
established. 


As  on  canals,  locks  are  required  in  or- 
der to  raise  the  vessels  from  a  lower  to  a 
higher  level,  and  vice  versa  ,•  so,  on  rail- 
ways, what  are  called  inclined  planes  are 
often  necessary  to  attain  the  difference  of 
level. 

These  inclined  planes  are  generally, 
compared  with  the  rest  of  the  rail-way, 
very  steep.  A  perpetual  chain  raises  and 
lowers  the  waggons.  It  is  so  contrived, 
that  the  waggons  disengage  themselves 
the  moment  they  arrive  at  the  upper  or 
lower  extremity  of  the  inclined  plane.  In 
some  cases,  the  laden  waggons  descend- 
ing serve  as  a  power  to  bring  up  the  emp- 
ty ones ;  but  where  there  is  an  ascending 
as  well  as  a  descending  traffic  on  the  rail- 
way, steam  engines,  water  wheels,  or  other 
machines  to  answer  the  same  purpose  are 
used.  At  Chapel  le  Frith,  there  is  an  in- 
clined plane  about  550  yards  long,  so  that 
the  chain  extended  is,  of  course,  more 
than  double  that  length. 

Most  railways  of  considerable  extent 
require  the  use  of  this  species  of  machi- 
nery for  attaining  the  difference  of  level 
requisite,  more  particularly  in  cases  where 
minerals  form  any  considerable  part  of 
the  traffic.  On  the  proposed  railway  be- 
tween Glasgow  and  Berwick,  several  in- 
clined planes  will  be  required;  the  sum- 
mit of  that  railway  being  753  feet  above 
the  level  of  the  end  qf  Berwick  quay. 

The  waggons  are  constructed  on  va- 
rious plans,  and  are  probably,  in  most 
cases,  far  from  the  degree  of  improve- 
ment of  which  they  are  susceptible.  But, 
with  all  their  disadvantages,  the  following 
facts  will  evince  the  great  saving  of  ani- 
mal force  to  which  railways  gave  rise. 

1.  With  1  1-4  inch  per  yard  declivity, 
one  horse  takes  downward  three  wag- 
gons, each  containing  two  tons. 

2.  In  another  place,  with  a  rise  of  one 
inch  and  six-tenths  per  yard,  one  horse 
takes  two  tons  upwards. 

3.  With  eight  feet  rise  in  66  yards, 
nearly  1  1-4  inch  per  yard,  one  horse 
lakes  two  tons  upwards. 

4.  On  the  Penryhn  railway,  (same  slope 
as  the  above,)  two  horses  draw  down- 
wards four  waggons,  each  containing  one 
ton  of  slate. 

5.  With  a  slope  of  55  feel  per  mile,  one 
horse  takes  from  12  to  15  tons  down- 
wards, and  four  tons  upwards,  and  all 
the  empty  waggons. 

6  At  Ayr,  one  horse  draws  on  a  level 
five  waggons,  each  containing  a  ton  of 
coal. 

7.  On  the  Surry  railway,  one  horse,  on 
a  declivity,  of  one  inch  in  ten  feet,  is  said 
to  draw  thirty  quarters  of  wheat. 

RAIN.    See  Meteorology. 


RAN 

RAISING  OF  WATER.  See  Hydrau- 
lics and  Engine. 

RAISINS,  are  grapes  prepared,  by  suf- 
fering them  to  remain  on  the  vine  till  they 
are  perfectly  ripe,  and  then  drying  them 
in  the  sun,  or  by  the  heat  of  an  oven.  The 
difference  between  raisins  dried  in  the 
sun  and  those  dried  in  ovens,  is  very  ob- 
vious :  the  former  are  sweet  and  pleasant, 
but  the  latter  have  a  latent  acidity  with 
the  sweetness,  that  renders  them  much 
less  agreeable. 

The  common  way  of  drying  grapes  for 
raisins  is  to  tie  two  or  three  bunches  of 
them  together  while  on  the  vine,  and  dip 
them  into  a  hot  lixivium  of  woodashes, 
with  a  little  of  the  oil  of  olives  in  it.  This 
disposes  them  to  shrink  and  wrinkle ;  and 
after  this  they  are  left  on  the  vine  three  or 
four  days,  separated  on  sticks,  in  an  hori- 
zontal situation,  and  then  dried  in  the  sun 
at  leisure,  after  being  cut  from  the 
tree. 

The  best  fruits  of  this  description,  are 
sun  and  jar  raisins ;  which  are  imported 
from  the  southern  countries  of  Europe, 
and  also  from  the  Asiatic  provinces  of 
Turkey.  They  yield  an  agreeable  wiye. 
For  which  purpose,  let  one  cwt  of  rai- 
sins be  deprived  of  their  stalks,  chop- 
ped, and  put  into  a  wide,  but  not  too 
deep,  vessel  :  Two-thirds,  or  fourteen 
gallons  of  water,  are  now  to  be  added, 
and  the  whole  suffered  to  stand  for  fifteen 
days,  being  carefully  stirred  once  every 
day.  At  the  end  of  that  period,  the  rai- 
sins  must  be  strained,  pressed,  and  the  li- 
quor obtained  from  them,  poured  into  an^ 
other  vessel.  The  remaining  third  part, 
or  seven  gallons  of  water,  should  next  be 
added  to  the  fruit,  thus  pressed,  and  like- 
wise stand  for  the  space  of  one  week. 
The  liquor  is  then  again  to  be  strained, 
and  the  two  runnings  are  to  be  poured  in- 
to a  barrel,  capable  of  containing  twenty- 
one  gallons,  together  with  a  quart  of 
brandy.  In  order  to  colour  the  wine,  three 
quarters  of  a  pound  of  refined  sugar  must 
be  set  on  fire,  and  burnt  into  a  little  of 
the  liquor,  which  ought  to  be  added  to 
the  whole  ;  and,  as  soon  as  the  fermenta- 
tion ceases,  the  barrel  may  be  closed,  and 
suffered  to  stand  till  its  contents  are  rea- 
dy for  bottling.... Raisin-wine  is  an  agreea- 
ble, cooling  liquor ;  but,  if  it  be  too  often 
used,  or  in  too  large  quantities,  it  is  apt 
to  occasion  flatulency. 

RANCIDITY.— The  change  which  oils 
undergo  by  exposure  to  the  air. 

Fixed  oil,  exposed  for  a  certain  time  to 
the  open  air,  absorbs  oxigen,  and  ac- 
quires a  peculiar  odour,  an  acrid  and 
burnt  taste,  at  the  same  time  that  it  be- 


RAN 

comes  thick  and  coloured.  If  oil  be  kept 
in  contact  with  oxigen  in  a  bottle,  it  be- 
comes more  speedily  rancid,  and  the  air 
is  absorbed.  Scheele  observed  the  ab- 
sorption of  a  portion  of  the  air,  before 
the  theory  was  well  ascertained.  Oil  is 
not  subject  to  alteration  in  closed  vessels. 

It  appears,  according  to  the  observa- 
tion of  Chaptal,  that  oxigen,  combined 
with  the  mucilage,  constitutes  rancidity ; 
and  that,  when  combined  with  the  oil  it- 
self, it  forms  drying  oil. 

The  rancidity  of  oils  is  therefore  an  ef- 
fect analagous  to  the  oxidation  of  metals. 
It  essentially  depends  on  the  combination 
of  oxigen  with  the  extractive  principle, 
which  is  naturally  united  with  the  oily 
principle.  This  inference  is  proved  by  at- 
tending to  the  processes  used  to  counter- 
act or  prevent  the  rancidity  of  oils. 

When  olives  are  prepared  for  the  ta- 
ble, every  endervour  is  used  to  depi-ive 
them  of  this  principle,  which  determines 
their  fermentation  ;  and  for  this  purpose 
various  methods  are  used.  In  some  places 
they  are  macerated  in  boiling  water 
charged  with  salts  and  aromatics  ;  and  af- 
ter twenty-four  hours  digestion  they  are 
steeped  in  clear  water,  which  is  renewed 
till  their  taste  is  perfectly  mild.  Some- 
times nothing  more  is  done  than  to  mace- 
rate the  olives  in  cold  water ;  but  they 
are  frequently  macerated  in  a  lixivium  of 
quick-lime  and  wood-ashes,  after  which 
they  are  washed  in  clear  water. 

But  in  whatever  manner  the  prepara- 
tion is  made,  they  are  preserved  m  a  pic- 
kle impregnated  with  some  aromatic 
plant,  such  as  coriander  and  fennel.  Some 
persons  preserve  them  whole  ;  others  split 
them,  for  the  more  complete  extraction 
of  their  mucilage,  and  in  order  that  they 
may  be  more  perfectly  impregnated  with 
the  aromatics. 

All  these  processes  evidently  tend  to 
extract  the  mucilaginous  principle,  which 
is  soluble  in  water,  and  by  this  means  to 
preserve  the  fruit  from  fermentation. 
When  the  operation  is  not  well  perform- 
ed, the  olives  ferment  and  change.  Chap- 
tal affirms,  that,  if  the  olives  be  treated 
with  boiling  water  to  extract  the  muci- 
lage before  they  are  submitted  to  the 
press,  a  fine  oil  will  be  obtained,  without 
danger  of  rancidity. 

When  the  oil  is  made,  if  it  be  strongly 
agitated  in  water,  the  mucilaginous  prin- 
ciple is  disengaged;  and  the  oil  may  be 
afterward  preserved  for  a  longtime  with- 
out change.  The  author  above  mention- 
ed preserved  oil  of  the  marc  of  olives, 
prepared  in  this  manner,  for  several  years 
in  open  bottles  without  any  alteration. 


■ 


RAT 


11EC 


The  torrefaction,  to  which  several  mu- 
cilaginous seeds  are  subje  cted  before  the 
extraction  of  the  oil,  renders  them  less 
susceptible  of  change,  because  the  muci- 
lage has  been  destroyed. 

.Mi*.  Sieffert  has  proposed  to  ferment 
oils  with  apples  or  pears,  in  order  to  de- 
prive rancid  oils  of  their  acrimony.  By 
this  means  they  are  cleared  of  the  princi- 
ple, which  had  combined  with  them,  but 
now  becomes  attached  to  other  bodies. 

Mucilage  may  therefore  be  considered 
as  the  principle  of  the  rancid  ferment. 

RAPE-SEED  OIL.— The  following  re- 
marks may  be  noticed  in  this  place. 

Mr.  Thevenard  lias  published  the  fol- 
lowing method  of  purifying  this  oil.  He 
directs  1£  or  2  parts  of  concentrated  sul- 
phuric acid  to  be  added  to  100  parts  of 
oil,  and  the  whole  to  be  perfectly  incor- 
porated by  agitation  :  the  fluid  immediate- 
ly becomes  turbid,  assuming  a  dark-green 
cast ;  and,  in  the  course  of  three  quar- 
ters of  an  hour,  the  colouring  particles 
begin  to  collect  in  lumps.  The  agitation 
must  now  cease :  and  double  the  weight 
of  oil  of  vitriol,  diluted  with  pure  water, 
should  be  added  :  in  order  to  mingle  these 
different  ingredients,  the  stirring  ought  to 
be  renewed  for  the  space  of  half  an  hour ; 
after  which  the  whole  may  be  left  to  set- 
tle for  seven  or  eight  days.  At  the  end 
of  that  time,  the  oil  will  be  found  on  the 
surface ;  on  being  gently  drawn  off',  and 
filtered  through  cotton  or  wool,  it  will  be 
almost  entirely  divested  of  colour,  smell, 
arid  taste  ;  so  that  it  will  burn  clear,  with- 
out any  interruption.    See  Oil. 

RASPBERRY,  the  Common,  Bram- 
ble, Framboise  Hind-Berry,  or  Ras- 
pis  ;  Rubus  Jdeaus,  L.--A11  indigenous  plant 
growing  in  damp  woods  and  hedges  ;  in 
thickets,  and  gravelly  places  near  rivulets : 
it  flowers  in  the  months  of  May  and  June. 
The  fruit  of  this  shrub,  in  a  natural  state, 
is  fragrant,  sub-acid,  cooling,  and  very- 
grateful  :  when  used  as  an  ingredient  of 
sweet -meats,  or  fermented  with  sugar, 
and  converted  into  wine,  or  vinegar,  its 
flavour  is  greatly  improved.  The  white 
berries  are  sweeter  than  the  red,  but  they 
are  generally  more  contaminated  by  in- 
sects. When  eaten  in  any  quantity,  and 
occasionally  held  in  the  mouth,  this  fruit 
is  said  to  dissolve  tartarous  concretions 
formed  on  the  teeth ;  though,  for  such 
purpose,  it  is  supposed  to  be  inferior  to 
strawberries.  The  young  and  fresh  leaves 
of  the  common  raspberry  are  eagerly  eat- 
en by  kids.    See  Wine. 

RATIFIA,  is  a  fine  spirituous  liquor, 
prepared  from  the  kernels,  &c.  of  several 
kindjs  of  fruit,  particularly  cherries  and 


apricots,  with  an  addition  of  spice  and 
brandy. 

Ratifia  of  cherries  is  prepared  by  burn- 
ing the  cherries,  and  putting  them  into  a 
vessel,  wherein  brandy  has  been  long 
kept :  then  adding  to  them  the  kerm  is  of 
cherries,  with  strawberries,  sugar,  cinna- 
mon, white  pepper,  nutmegs,  cloves,  and 
to  twenty  pounds  of  cherries,  ten  quarts 
of  brandy.  The  vessel  is  left  open  ten  or 
twelve  days,  and  then  stopped  close  for 
two  months  before  it  be  tapped. 

Ratifia  is  chiefly  distilled  by  the  French. 
See  Distilled  Spirits. 

RAWLINSON'6  COLOUR-MILL.  See 
Mechanics. 

RAZORS.    Sec  Cutlery. 

REAGENTS,  in  Chemistry.  See  Tests. 

R E ALGAR.    See  Arsenic. 

RECEIVER. — Receivers  are  chemical 
vessels,  which  are  adapted  to  the  necks 
or  beaks  of  retorts,  alembics,  and  other 
distillatory  vessels,  to  collect,  receive,  and 
contain  the  products  of  distillations. 

Receivers  ought  to  be  made  of  glass, 
not  only  because  this  matter  resists  the 
action  of  the  strongest  and  most  corrosive 
substances,  but  also  because,  being  trans- 
parent, it  allows  the  operator  to  see 
through  it,  and  to  judge,  by  the  frequen- 
cy of  the  drops,  whether  the  distillation 
proceed  too  fast  or  too  slow,  and  also 
whether  the  quantity  and  nature  of  the 
substances  which  come  over  be  such  as 
are  required. 

Almost  all  receivers  are  a  kind  of  bot- 
tles of  different  sizes,  of  a  spherical  form, 
the  necks  of  which  are  cut  short,  and 
each  of  which  is  pierced  with  a  small 
hole  in  its  lateral  or  upper  part,  to  give 
vent  to  the  air  or  vapours  which  are  too 
expansive.  Receivers  of  this  form  are 
called  balloons. 

Some  receivers  are  matrasses  with  long 
necks.  These  are  generally  adapted  to 
the  beaks  of  glass  alembics.  This  long 
neck  serves  to  keep  the  belly  of  the  re- 
ceiver, where  the  liquor  is  collected,  at  a 
proper  distance  from  the  fire. 

Receivers  have  different  forms  for  par- 
ticular operations.  Such  are  those  which 
have  two  or  three  beaks,  either  to  be 
adapted  to  other  receivers,  or  to  admit  at 
the  same  time  the  necks  of  several  distil- 
latory vessels,  when  the  intention  of  the 
operator  is,  that  the  vapours  of  different 
substances  should  meet  in  the  same  re- 
ceiver. Such  also  are  receivers  for  essen- 
tial oils,  which  are  very  convenient  for 
the  distillation  of  these  oils  To  obtain 
the  essential  oil  of  aromatic  plants,  these 
plants  must  be  distilled  with  water.  The 
plant  and  the  water  are  to  be  put  toge- 


REC 


EEC 


ther  into  a  cucurbit,  and  the  water,  which 
is  to  receive  a  boiling-  heat,  rises  in  distil- 
lation, carrying  with  it  the  essential  oil, 
which  also  has  the  properly  of  rising-  with 
this  degree  of  heat,    bee  Gi  ls. 

As  a  large  quantity  of  water  must  be 
employed,  that  the  plant  may  always  be 
kept  immersed  in  the  alembic,  and  conse- 
quently as  a  good  deal  of  it  rises  in  pro- 
portion to  the  oil,  any  receiver  of  ordina- 
ry siz.e  would  be  soon  filled  w  ith  water 
with  a  little  oil  floating  upon  its  surface, 
and  would  require  to  be  frequently  chang- 
ed ;  which  would  be  very  troublesome, 
and  would  occasion  a  loss  of  part  of  the 
oil. 

These  inconveniences  are  avoided  by 
using  receivers  contrived  purposely  for 
such  distillations.  They  are  so  made, 
that  they  are  never  full,  but  that  the  wa- 
ter runs  out,  and  leaves  the  oil  behind. 
They  are  akind  of  glass  cucurbits,  which 
contract  as  they  rise  higher;  so  that  their 
neck,  or  upper  opening,  is  but  nearly  of  a 
convenient  size  to  receive  the  beak  of  the 
worm.  These  receivers  have  another 
opening  about  the  middle  of  the  swelling 
or  belly ;  and  to  this  opening  is  joined  a 
glass  tube,  which  bends  and  rises  verti- 
cally along  the  outer  part  of  the  receiver, 
so  as  to  be  within  two  inches  and  a  half 
as  high  as  the  upper  opening.  At  this 
height  the  tube  bends  again  towards  the 
side  opposite  to  the  body  of  the  receiver, 
to  pour  into  another  vessel  the  liquor 
which  rises  there.  It  forms  the  figure 
of  8. 

When  this  receiver  is  to  be  used,  it  is 
to  be  placed  vertically  under  the  beak  of 
the  worm.  During  the  distillation,  the  li- 
quor rises  to  an  equal  height  in  the  body 
of  the  receiver  and  in  the  crocked  tube : 
when  therefore  the  height  of  the  liquor 
in  the  receiver  becomes  greater  than  the 
height  of  the  tube,  it  must  begin  to  flow 
from  the  mouth  of  this  tube  into  another 
vessel  placed  on  purpose  to  receive  it  : 
but  as  essential  oils  are  either  lighter  or 
heavier  than  water,  and  as  they  are  there- 
fore always  collected  either  above  or  un- 
der the  water,  and  as  the  liquor  which 
discharges  itself  through  the  tube  is  ta- 
ken from  the  middle  part  of  the  receiver, 
therefore  nothing  but  water  can  be  eva- 
cuated at  the  mouth  of  the  pipe,  while 
the  oil  always  remains  in  the  receiver 
Thus,  with  such  a  receiver,  w  e  may  distil 
without  the  trouble  of  changing  the  vcs-  i 
sels ;  which  is  certainly  very  advantage- 
ous. 

RECTIFICATION".    By  rectification  is  < 
meant  the  exact  purfication  of  certain  sub- 
stances, by  means  of  distillation  or  subli- 
mation. 


This  operation  is  necessary  to  disen- 
.  gage  many  chemical  products  or  agents, 
from  a  mixture  of  extraneous  matters, 
which  destroy  their  purity.  Thus,  for 
instance,  sulphuric  acid,  when  first  ob- 
tained from  sulphat  of  iron,  or  from  sul- 
pliur,  is  always  mixed  with  a  considera- 
ble quantity,  either  ot  sulphurous  acid,  or 
of  superabundant  water,  which  weakens 
it.  It  is  separated  from  both  these  mat- 
ters by  a  second  distillation,  in  which 
they,  being  more  volatile  than  the  acid, 
are  carried  off;  v\  Inch  second  distillation 
is  eaiied  concentration  or  rectification  of 
sulphuric  acid. 

Also,  when  animal  and  vegetable  mat- 
ters are  decomposed  by  distillation,  all 
the  portion  of  oil  that  is  not  volatile,  con- 
tained in  these  substances,  does  not  rise 
but  With  a  degree  of  fire,  so  strong  as  to 
burn  a  part  ot  them,  and  to  raise  along 
with  them,  a  considerable  portion  of  sa- 
line substances,  which  being  mixed  with 
the  oily  part,  considerably  alter  its  purity. 
To  purity  these  oils,  which  from  their 
burnt  smell,  are  called  empvreumatic, 
new  distillations  must  be  apphed,in  which 
by  means  of  a  less  heat,  the  most  volatile 
and  purest  part  of  these  oils,  is  separated 
from  the  most  einpyreumatic  and  saline 
parts,  Which  remain  at  the  bottom  of  the 
retort:  tins  is  called  the  rectification  of 
empyreunuitic  oils.    See  Oil. 

The  alcohol  obtained  by  a  first  distilla- 
tion ot  liquors,  which  have  undergone 
the  spirituous  fermentation,  is  overcharg- 
ed with  a  large  quantity  of  water  and 
light  oil,  which  rise  along  with  them  in 
this  first  distillation.  The  product  of  this 
distillation  has  been  called  aqua  vitae.  It 
is  an  ardent  spirit,  very  far  trom  the  de- 
gree of  dephlegmation  and  purity  which 
alcohol  ought  to  have,  to  render  it  fit  for 
chemical  operations,  and  for  several  com- 
pounds commonly  used,  such  as  perfum- 
ed waters  and  liqueurs  for  the  table  

This  spirit  is  to  be  purified  by  new  dis- 
tillations, slowly  conducted  with  a  gentle 
fire,  and  water-bath;  by  means  oi  which 
the  most  volatile  part,  that  always  rises 
first  with  the  least  heat,  and  which  is  the 
true  a.cohol,  is  separated  from  the  less 
volatile  part,  that  remains  in  the  alembic, 
and  winch  contains  the  phlegm  and  oil 
of  w  ine,  by  which  the  alcohol  was  render- 
ed impure.  The  first  liquor  of  these 
second  distillations  or  rectifications,  is 
called  rectified  spirit  of  wine.  See  Al- 
cohol 

The  volatile  salts  obtained  in  the  de- 
composition of  certain  ohy  substances,  as 
volatile  alkalies,  from  deco  -posed  ani- 
mal matters,  are  always  very  ni!puu;,and 
spoiled  by  much  empyreumatic  oil,  which 


KEE 


KEF 


rises  along  with  them.  They  are  purified 
and  disengaged,  by  subjecting  them  to 
new  distillations  or  sublimations,  with  a 
well  conducted  heat.  The  same  obser- 
vation is  applicable  to  muriat  of  antimony, 
artificial  cinnabar,  phosphorus,  and  to 
many  other  chemical  products,  which  are 
always  impure,  when  obtained  by  a  first 
operation,  and  must  therefore  be  puriiied 
by  a  second  distillation  or  sublimation. 
All  these  second  operations,  intended 
merely  to  purity  matters,  aie  called  rec- 
tifications. They  are  not  generally  at- 
tended with  much  difficulty*  We  shall 
not  therefore,  enter  into  the.  details  of 
them  ;  but  we  shall  only  observe,  that  all 
rectifications,  are  founded  upon  the  same 
principle.  They  all  consist  in  separating 
biibstances  more  volatile,  from  substances 
less  volatile  ;  and  the  general  method  of 
effecting  this,  is  to  apply  only  the  degree 
of  heat,  which  is  necessary  to  cause  tins 
separation.  See  Distillation  and  Sub- 
limation'. 

Ri£.D  CHALK,  or  Reddle,  an  ore  of 
iron  in  the  state  of  red  oxyd,  commonly 
used  as  a  pigment. 

R E D  LEAD.    See  Lead. 

RED  COLOURS.  See  Dyeing  and 
Colour-Maki  sg. 

RED  INK,  is  usually  prepared,  by  in- 
fusing four  ounces  of  the  raspings  of  Bra- 
zil-wood, and  two  drachms  of  pulverized 
alum,  in  equal  quantities,  namely,  a  pint 
of  rain-water  and  vinegar,  for  two  or  three 
days  ;  at  the  expiration  of  which  time, 
the  infusion  is  boiled  over  a  moderate  fire, 
till  the  third  part  of  the  fluid  be  evapo- 
rated. It  is  then  suffered  to  stand,  for 
three  or  four  days,  when  it  is  filtered 
through  blotting  paper,  and  preserved  for 
use,  in  close  vessels.  There  is  no  occa- 
sion for  adding  gum  arabic,  which  only 
tends  to  suspend  impurities,  while  it 
changes  the  ink  to  a  pale  purple  shade. 
Another  mode  of  making  red  ink,  consists 
in  triturating  tlie  whites  of  four  eggs,  and 
a  tea-spoonful  of  pounded  lump  sugar, 
with  a  similar  quantity  of  spirit  of  jvine^ 
till  they  acquire  an  uniform  consistence. 
Vermillion  is  then  to  be  incorporated,  in 
such  a  proportion  as  will  produce  a  red 
colour  of  sufficient  strength.  The  liquor 
must  be  kept  in  a  well  closed  vessel,  and 
agitated  every  time  before  it  is  used.  See 
life. 

RED  SAUXDERS,  a  dyeing  or  colour- 
ing drug.    See  Dyeing. 

REED,  or  Arundo,  L.  a  genus  of 
plants,  comprising  ten  species  :  of  which 
the  following  are  the  principal,  namely: 

The  arcnaria,  ( Calamagrostis  uraturia 
of  Dr.  Withering)  or  Sea-Reed. 

The  p/iragmitcs}or  common-reed,grows 


in  rivers,  lakes,  ditches,  and  fenny  or 
marshy  situations,  to  the  height  of  seven 
or  eignt  feet :  it  is  perennial,  and  flower* 
in  the  month  of  July.  This  species  is 
employed  lor  covering  cottages  and  barns; 
for  which  purpose  it  is  superior  to  every 
oilier  indigenous  vegetable,  being  incom- 
parably more  neat  and  durable.  By  pre- 
viously soaking  the  reeds,  in  strong* alum 
water,  such  a  roof  may  be  rendered  fire- 
proof. They  are  also  manufactured  into 
screens,  for  sheltering  young  plants, 
from  the  cold  winds ;  and  may  be  usefully 
employed  for  cane-bottomcd  chairs.  Far- 
ther, the  common  reed  makes  excellent 
weaver's  combs,  and  is  generally  nailed 
across  the  frame  of  wood  work,  to  serve 
as  the  foundation  of  plaistered  walls,  pil- 
lars, &,c.  From  the  dried  roots  of  this 
plant,  a  very  nutritive  flour  is  easily  ob- 
tained, which  may  be  converted  into  whole- 
some  and  palateable  bread.  Its  panicles 
are  used,  in  Sweden,  to  impart  a  Teen 
colour  to  wool. 

The  tpigtois,  (■  calamagrostis  epigeios 
of  Withering)  or  wood  reed,  is  perennial, 
grows  m  shady  ditches,  and  moist  situa- 
tions, where  it  flowers  in  July.  It  is  ma- 
nufactured into  hassocks,  or  thick  mats 
for  churches.  "  ' 

The  calamagrostis  ( lanceolata  of  Dr 
Withering)  small  or  hedge-reed,  is  like- 
wise perennial ;  grows  in  moist  shady 
hedges  and  meadows ;  where  it  flowers 
in  the  month  of  July.  This  species  is  re- 
markable for  its  beauty,  and  is  an  orna- 
ment to  ditch-banks  and  hedges  Pro- 
fessor Pallas,  observes,  that  the  panicles 
of  the  small  reed,  before  the  flower  ex- 
pands, impart  a  beautiful  bright-green 
colour  to  wool,  when  boiled,  with  the  ad- 
dition of  alum. 

REFINING,  is  a  term  used  in  chemis* 
try  and  several  arts,  to  signify  the  purifi- 
cation of  some  substance,  particularly 
ot  metals,  as  golds,  silver,  copper,  iron, 

We  shal  l  here  treat  only  of  the  refining 
of  goid  and  silver ;  and  for  the  refining  of 
other  substances,  we  refer  to  their  seve- 
ral articles. 

Gold  and  silver  may  be  refined,  by  se- 
veral methods,  which  are  all  founded  on 
the  essential  properties  of  these  metals, 
and  acquire  different  names  according  to 
their  kinds.  Tims  for  instance,  gold,  hav- 
ing the  property  which  no  other  metal, 
not  even  silver,  has  of  resisting  the  ac- 
tion of  sulphur,  of  antimony,  of  nitric  acid, 
of  muriatic  acid,  may  be  purified  by  these 
agents,  from  all  other  metallic  substances, 
and  consequently  may  be  refined.  These 
operations  are  distinguished  by  proper 
names,  as  purification  of  gold  by  antimo- 


REF 


REF 


nv,  parting,  concentrated  parting,dry  part-  J 
ing.    In  a  similar  manner,  as  silver  has 
the  property,  which  the  imperfect  metals 
have  not,  of  resisting  the  action  of  nitre, 
it  may  be  refined  by  this  salv ;  but  the 
term  refining-  is  chiefly  applied  to  the  pu- ; 
rification  of  gold  and  silver,  by  lead  in  the  \ 
cupel 

The  refining  of  gold  and  silver,  by  lead 
in  the  cupel,  is  performed  by  the  destruc- , 
tion,  vitrification  and  scorification,  of  all  | 
the  extraneous  and  destructible  metal- 
lic substances,  with  which  they  are  alloy- 
ed. 

As  none  but  the  perfect  metals  can  re- 
sist the  combined  action  of  air  and  fire, 
without  being  oxided,  and  thus  changed 
into  earthy  or  vitreous  matters,  incapable 
of  remaining  any  longer  united,  with  sub- 
stances in  a  metallic  state  ;  there  is  a  pos- 
sibility of  purifying  gold  and  silver,  from 
all  alloy  of  imperfect  metals,  merely  by 
the  action  of  tire  and  air  j  only  by  keep- 
ing them  fused,  till  all  the  alloy  is  destroy- 
ed :  but  this  purification  would  be  very 
expensive,  from  the  great  consumption  of 
fuel,  and  wouid  be  exceedingly  tedious. 
Macquer  says,  he  has  seen  silver  alloyed 
with  copper,  exposed  longer  than  sixty- 
hours  to  a  glass-house  fire,  without  being 
perfectly  refilled  :  the  reason  of  which,  is 
that  when  a  small  quantity  only,  remains 
united  with  gold  or  silver,  it  is  covered 
and  protected,  from  the  action  of  the  air, 
which  is  necessary  for  the  combustion  of 
the  imperfect  metals,  as  of  all  combusti- 
ble matters. 

This  refining  of  gold  and  silver,  merely 
by  the  action  of  lire,  which  was  the  only 
Tilethod  anciently  known,  was  very  long, 
difficult,  expensive,  and  imperfect:  but  a 
much  shorter  and  more  advantageous  me- 
thod, has  been  discovered.  This  method 
consists  in  adding  to  the  alloyed  gold  and 
silver,  a  certain  quantity  of  lead,  and  in 
exposing  afterwards  this  mixture  to  the 
action  of  the  fire.  Lead  is  one  of  the  me- 
tals, which  are  most  quickly  and  easily 
oxided  :  but  at  the  same  time,  this  metal 
has  the  remarkable  property,  of  being 
very  easily  melted,  into  a  vitrified,  and 
powerfully  vitrifying  matter,  called  li- 
tharge. 

The  lead,  which  is  to  be  added  to  the 
gold  and  silver  to  be  refined,  or  which 
happens  naturally  to  be  mixed  with  these 
metals,  produces  in  their  refining,  the  fol- 
lowing advantages : 

1.  By  increasing  the  proportion  of  im- 
perfect metals,  it  prevents  them  from 
being  so  well  covered  and  protected,  by 
the  perfected  metals. 

2.  By  uniting  with  these  imperfect  me- 


tals, it  communicates  to  them  a  property 
it  has,  of  being  very  easily  oxyded. 

3.  Lastly,  by  its  vitrifying  and  fusing 
property,  which  it  exercises  with  all  its 
force,  upon  the  oxyded  and  naturally  re- 
fractory parts  of  the  other  metals,  it  faci- 
litates and  accelerates  the  fusion,  the  sco- 
rification,  and  the  separation  of  these  me- 
tals. These  are  the  advantages  pro- 
cured by  lead,  in  the  refining  of  gold  and 
silver. 

The  lead,  which  in  this  operation  is  sco- 
rified, and  scorifies  along  with  it  the  im- 
perfect metals,  separates  from  the  metal- 
lic mass,  with  which  it  is  then  incapable 
of  remaining  united.  It  floats  upon  the 
surface  of  the  melted  mass,becauseit  loses 
also  part  of  its  specific  gravity  :  and  lastly 
it  vitrifies. 

These  vitrified  and  melted  matters,  ac- 
cumulating more  and  more,  upon  the  sur- 
face of  the  metal,  while  the  operation  ad- 
vances, would  consequently  protect  this 
surface  from  the  contact  of  air,  which  is 
absolutely  necessary  for  the  scorification 
of  the  rest,  and  wouid  thus  stop  the  pro- 
gress of  the  operation,  which  could  never 
be  finished,  if  a  method  had  not  been  con- 
trived for  their  removal.  This  removal 
of  the  vitrified  matter,  is  procured  either 
by  tne  nature  of  the  vessel,  in  which  the 
melted  matter  is  contained,  and  which 
being  porous  absorbs  and  imbibes  the  sco- 
rified matter,  as  fast  as  it  is  formed ;  or 
by  a  channel,  cut  in  the  edge  of  the  ves- 
sel, through  which  the  matter  flows  out. 

The  vessel  in  which  the  refining  is 
performed  is  flat  and  shallow,  that  the 
matter  which  it  contains,  may  present  to 
the  air  the  greatest  surface  possible. — 
This  form  resembles  that  of  a  cup,  and 
hence  it  has  been  called  cupel.  The  fur- 
nace ought  to  be  vaulted,  that  the  heat 
may  be  applied  upon  the  surface  of  the 
metal,  during  the  whole  time  of  the  ope- 
ration. Upon  this  surface  a  crust  or  dark- 
coloured  pellicle,  is  continually  forming-. 
In  the  instant,  when  all  the  imperfect  me- 
tal is  destroyed,  and  consequently  the 
scorification  ceases,  the  surface  of  the  per- 
fect metais  is  seen,  and  appears  clean  and 
brilliant.  This  forms  a  kind  of  figura- 
tion or  coruscation.  By  this  mark  the 
metal  is  known  to  be  refined.  If  the  ope- 
ration be  so  conducted,  that  the  metal 
sustains  Only  the  precise  degree  of  heat 
necessary  to  keep  it  fused,  before  it  be 
perfectly  refined,  we  may  observe,  that 
it  fixes  or  becomes  solid,  all  at  once  in  the 
very  instant  of  the  coruscation  ;  because 
a  greater  heat,  is  required  to  keep  silver 
or  gold  in  fusion,  when  they  are  pure,  than 
when  alloA  ed  with  lead. 


REF 


REF 


Tlie  operation  of  refining,  may  be  per- 
formed in  small  or  large  quantities,  upon 
the  same  principles,  but  only  with  some 
differences  in  the  management. 

Large  quantities  of  silver  is  thus  puri- 
fied, utter  the  operations  by  which  that 
metal  is  obtained  from  its  ores.  This  sil- 
ver, being  always  much  alloyed,  is  to  be 
mixed  with  a  sufficient  quantity  of  lead, 
to  complete  its  purification,  unless  lead 
has  been  added,  in  its  first  fusion  from 
the  ore,  or  unless  it  has  been  extracted, 
from  an  ore  which  also  contains  lead  ;  in 
which  latter  case  it  is  alloyed  naturally, 
with  a  sufficient  quantity,  or  more  than 
sufficient,  for  the  refining  of  it.  See  Oues 
of  Silver.  One  of  the  ores  of  this 
kind,  which  is  treated  in  the  best  manner, 
is  the  ore  of  liamelsberg  in  Saxony.  'The 
several  operations,  which  arc  practised  in 
this  country  abounding  in  mines,  and  ex- 
cellent metallurgists,  have  been  exactly 
described  by  Schlutter.  We  shall  here 
give  a  sufficient  extract,  of  the  method 
of  purifying  large  quantities  of  silver, 
from  Hellot's  translation  of  Schlutter's 
work. 

The  workmen  give  the  name  of  the  work 
to  the  lead  containing  silver,  obtained  by 
smelting  the  ore  of  Ramelsberg.  The  first 
operation,  called  fining,  upon  this  mass 
of  lead  and  silver,  is  performed  in  a  fur- 
nace called  a  reverberatory  furnace,  from 
the  vaulted  form,  which  makes  the  heat 
reverberate,  upon  the  surface  of  the  me- 
tal. This  furnace  is  so  constructed,  that 
the  flame  of  the  wood,  which  is  put  into 
the  fire-place,  through  a  hole  called  the 
fire-hole,  is  directed,  so  as  to  circulate 
over  the  work  within  the  furnace.  The 
flame  is  thus  directed  by  a  current  of  air, 
which  is  introduced  through  the  ash-hole, 
and  passes  out  at  an  opening  made  at  the 
side  of  the  place,  where  the  work  is.  The 
wood  is  considerably  saved  by  this  direc- 
tion of  the  flame.  In  the  furnace  a  large 
cupel  or  test,  is  to  be  disposed.  This 
test  is  to  be  made  with  ashes  of  beech- 
wood  well  lixiviated,  that  the  salt  may  be 
washed  from  them. 

In  some  foundries,  different  matters  are 
added  to  the  ashes,  as  sand,  lime,  clay, 
calcined  spar,  or  gypsum.  We  may  ob- 
serve, concerning  these  additions,  that 
they  would  be  very  injurious,  and  would 
make  the  test  melt,  if  a  strong  heat  were 
applied ;  but  the  heat  requisite  for  fining', 
is  only  moderate. 

When1  the  test  is  well  prepared  and 
dried,  all  the  work  is  to  be  put  into  it  at 
once,  which  is  generally  sixty -four  quin- 
tals :  the  fire  is  then  to  be  made  in  the 
fire-place,  with  faggots  ;  but  the  fusion  is 
VOL.  II. 


not  to  be  too  much  hastened,  first,  that 

the  test  may  have  time  to  dry  thoroughly, 
which  is  very  essential;  for  it  any  moisture 
remained  when  the  metal  is  melted,  an 
explosion  might  happen  :  secondly,  be- 
cause the  work  of  the  ore  at  Ramelsberg, 
and  of  most  others,  is  rendered  impure, 
by  the  mixture  of  many  metallic  matters, 
which  ought  to  be  separated,  otherwise 
they  would  spoil  the  litharge,  and  give  a 
bad  quality  to  the  lead  afterward  obtain- 
ed, from  that  litharge.  These  extrane- 
ous matters,  found  in  the  work  of  liamels- 
berg, are,  copper,  iron,  and  malt.  As 
these  substances  are  hard  and  refractory, 
they  do  not  melt  so  soon  as  the  work,  if 
the  heat  be  moderate;  and  besides,  as 
they  are  specifically  lighter,  than  the  mix- 
ture of  lead  and  silver,  they  float  upon 
the  surface  of  these  two  metals  when 
melted,  inform  of  a  pellicle  or  skin,  which 
is  to  be  taken  off.  These  impurities  are 
called  the  scum  or  dross.  The  remain- 
der forms  also  a  scum,  which  appears 
when  the  work  has  received  more  heat, 
but  before  the  litharge  has  began  to  form. 
This  is  a  scoria,  which  is  to  be  careful- 
ly taken  off,  and  is  called  the  second 
dross. 

When  the  operation  is  come  to  this 
point,  it  is  to  be  continued  by  means  of 
bellows,  the  air  of  which  is  directed  not 
on  the  wood,  but  on  the  surface  of  the  me- 
tals, by  means  of  iron  plates,  placed  for 
that  purpose,  before  the  blast  hole,  and 
which  are  called  papillons.  This  air  is 
not  intended  to  increase  the  fire,  but  to 
facilitate  the  combustion  of  the  lead,  and 
to  push  the  litharge  to  a  channel,  in  the 
opposite  side  of  the  test.  This  channel, 
is  called  the  way  of  the  litharge,  because 
through  this  passage  all  the  litharge, 
which  is  not  imbibed  by  the  test,  flows 
out  of  the  furnace  The  litharge  which 
is  found  in  the  middle  of  the  largest  lumps 
is  friable,  and  crumbles  into  powder  like 
sand.  It  is  put  into  casks,  each  of  which 
contains  five  quintals  of  it,  and  is  sold  by 
the  name  of  saleable  litharge.  The  quan- 
tity of  this  is  about  one-half  or  one-third 
of  the  whole  litharge,  that  is  formed.  It 
is  used  for  various  purposes,  and  particu- 
larly for  glazing  earthen  ware.  The  other 
part  which  remains,  is  called  cold  litharge, 
it  is  remelted,  and  reduced  to  lead.  This 
fusion  is  called  cold  fusion,  and  the  lead 
produced  frota  it,  called  cold  lead,  is  good 
and  saleable,  when  the  work  has  been 
well  purified,  from  the  extraneous  mat- 
ters mentioned  above.  The  tests  impreg- 
nated with  litharge,  are  added  to  the  same 
kind  of  ore  when  smelted  ;  because  they 
contain  not  only  much  litharge,  which 
S  S 


REF 


REG 


may  be  reduced  to  lead,  but  also  some 
silver,  in  all  refinings,  whether  in  the  large 
or  small  way,  as  Mr.  Tillet  observes. 

When  about  two-thirds  of  the  work  are 
converted  into  litharge,  no  more  litharge 
is  formed :  the  silver  is  then  covered  with 
a  sort  of  white  skin,  which  the  refiners  call 
lightening  and  they  call  the  metal  light- 
ened silver  or  fined  silver.  The  silver 
thus  fined  is  not  pure  ;  every  marc  of  it, 
contains  about  four  gros  of  lead  :  the  pu- 
rification of  it,  is  completed  in  the  ordi- 
nary method  ;  that  is,  by  a  second  cupel- 
lation  with  a  hotter  fire ;  which  latter  pu- 
rification is  called  refining,  and  the  per- 
sons who  perform  it,  are  called  refiners. 
The  workmen  employed  in  this  first  ope- 
ration, or  fining,  give  improperly  the  name 
lightening,  to  the  white  skin  formed  on 
the  surface  of  the  silver,  when  brought 
only  to  a  certain  degree  of  fineness  ;  for 
we  know  that  in  assays,  the  lightening  or 
coruscation  above  mentioned,  does  not 
appear,  but  when  the  silver  is  perfectly 
fine,  or  at  least  as  fine  as  it  can  be  made 
by  cupellation. 

A  fining  of  sixty-four  quintals  of  work 
of  iiamelsberg,  yields  about  eight  or  ten 
marcs  of  fine  silver,  thirty-five  or  forty 
quintals  of  litharge,  that  is,  from  twelve 
to  eighteen  of  saleable  litharge,  from 
twenty-two  to  twenty-three  of  cold  li- 
tharge, from  twenty  to  twenty-two  quin- 
tals of  tests,  and  six  or  seven  quintals  of 
dross.  This  operation  lasts  from  sixteen 
to  eighteen  hours. 

If  the  silver  (before  these  operations) 
were  alloyed  by  gold,  it  retains  this  gold 
still  after  the  fining  and  refining.  The 
gold,  if  the  quantity  be  considerable 
enough,  may  be  separated  by  parting- 
The  operations  for  the  purification  of  gold 
by  cupellation,  are  perfectly  the  same  as 
those  of  silver.  If  the  gold  to  be  fined 
contains  silver,  this  silver  remains  with  it 
after  the  operation,  because  both  these 
metals  resist  the  action  of  lead.  The  sil- 
ver may  afterward  be  separated  by  part- 
ing. 

REFRIGERATORY. — A  refrigeratory 
is  a  copper  vessel  soldered  round  the  ca- 
pital of  the  alembic.  Its  use  is  to  contain 
cold  water,  which  is  to  be  renewed  when 
it  is  heated,  and  the  hot  water  is  to  be 
let  out  at  a  cock  fitted  to  the  refrigerato- 
ry for  this  purpose.  The  intention  of  this 
renewal  of  the  water  of  the  refrigeratory, 
is  to  keep  perpetually  cool  the  capital  of 
the  alembic,  that  the  vapours  of  the  liquor 
which  rise  in  distillation  may  be  condensed 
more  easily  and  more  quickly. 

These  refrigeratories  were  much  used 
formerly,  and  all  alembics  were  furnished 
with  them;  but  modern  distillers  find 


that  this  vessel  is  not  attended  with  the 
advantages  it  was  formerly  believed  to 
possess ;  for  the  distillation  cannot  suc- 
ceed unless  the  capital  of  the  alembic  be 
as  hot,  or  almost  as  hot,  as  the  cucurbit. 
Mr.  Baume  observed,  that,  when  the  ca- 
pital was  cooled  by  very  cold  water,  the 
distillation  was  soon  stopped,  and  did  not 
again  begin  till  the  capital  was  considera- 
bly heated. 

The  refrigeratory  has  for  these  reasons 
been  much  neglected,  and  a  worm  sub- 
stituted in  place  of  it,  which  is  indeed  a 
kind  of  refrigeratory,  but  different  from 
the  other  in  this  respect,  that  it  is  adapt- 
ed to  the  nose  of  the  alembic,  instead  of 
surrounding  the  capital. 

This  remedy,  appears,  however,  to  be 
in  some  measure  inadequate,  because  the 
head  produces  a  considerable  return  of 
spirit,  even  without  a  refrigeratory.  It 
seems,  nevertheless,  that  the  inconve- 
nience of  this  last  addition  arises  merely 
from  the  large  aperture  of  the  neck.  See 
Alcohol. 

REGISTER. — Registers  are  openings 
in  different  parts  of  furnaces,  which  are 
to  be  shut  occasionally  with  stoppers  of 
burnt  clay.  By  means  of  registers  we 
may  govern  the  fire  as  we  please  ;  for,  by 
opening  or  shutting  them  properly,  we 
may  not  only  increase  or  diminish  the  ac- 
tivity of  the  fire,  but  also  we  may  apply 
its  action  more  to  one  part  of  the  furnace 
;  than  another,  by  giving  direction  to  the 
1  current  of  air,  which  passes  through  it. 

Notwithstanding  the  utility  of  registers, 
they  are  too  much  neglected.  Many  che- 
mists have  disused  registers,  probably  be- 
,  cause  they  did  not  find  the  advantages 
(from  them  which  they  expected.  The 
|  reason  of  this  is,  that  registers  have  hi- 
jtherto  been  ill  made.     Their  principal 
fault  is,  that  they  are  generally  too  small. 
A  register  cannot  have  its  proper  effect, 
unless  it  have  an  opening  of  two,  three, 
or  four  inches  for  a  furnace,  the  internal 
diameter  of  which  is  a  foot ;  but  we  fre- 
quently see  furnaces  of  eighteen  or  twenty 
inches  in  diameter,  with  registers,  the 
openings  of  which  are  scarcely  eight  or 
ten  lines.  Besides,  some  who  use  furnaces 
are  far  from  understanding  their  construc- 
tion. 

REGULUS. — The  name  regulus  was 
given  by  chemists  to  metallic  matters 
when  separated  from  other  substances  by 
fusion.  This  name  was  introduced  by  al- 
chemists, who,  expecting  always  to  find 
gold  in  the  metal  collected  at  the  bottom 
of  their  crucibles  after  fusion,  called  this 
metal,  thus  collected,  regulus,  as  contain- 
ing gold,  the  king  of  metals.  It  was  af- 
terward applied  to  the  metal  extracted 


mio 


RIIO 


from  the  ores  of  the  semimetals,  which 
formerly  bore  the  name  that  is  now  given 
to  the  semimetals  themselves.  Thus  we 
had  regulus  of  antimony,  regulus  of  ar- 
senic, and  regulus  of  cobalt. 

RENNET,  or  Hunnet,  is  the  stomach  of 
calves,  or  more  properly  is  the  coagula- 
ted milky  substance  which  is  found  in  the 
stomach  of  calves,  which  have  received 
no  other  nourishment  than  the  maternal 
milk.  On  the  use  of  rennet,  see  Cheese, 
and  Milk. 

RESOLUTION  OF  FORCES.  See  Me- 
chanics. 

RETORTS,  are  vessels  used  in  distilla- 
tion. They  are  formed  of  glass,  metal,  or 
earthen  ware.    See  Distillation. 

RETINASPHALTUM.  See  Bitu- 
men. 

RHODIUM. — A  new  metal  discovered 
among  the  grains  of  crude  platina  by  Dr. 
Wollaston.  The  mode  of  obtaining  it  in 
the  state  of  a  triple  salt,  combined  with 
muriatic  acid  and  soda,  has  been  given 
under  the  article  Palladium.  This  may 
be  dissolved  in  water,  and  the  oxide  pre- 
cipitated from  it  in  a  black  powder  by 
zinc. 

This  oxide  exposed  to  heat  continues 
black  ;  but  witli  borax  it  acquires  a  white 
metallic  lustre,  though  it  remains  infusi- 
ble. Sulphur,  or  arsenic,  however,  ren- 
ders it  fusible,  and  may  afterwards  be  ex- 
pelled by  continuing  the  heat.  The  but- 
ton, however,  is  not  malleable.  Its  speci- 
fic gravity  appears  to  exceed  11. 

Rhodium  unites  easily  with  every  me- 
tal that  has  been  tried,  except  mercury. 
With  gold  or  silver  it  forms  a  very  mallea- 
ble alloy,  not  oxidated  by  a  high  degree  of 
heat,  but  becoming  encrusted  with  a  black 
oxide  when  slowly  cooled.  One  sixth  of 
it  does  not  perceptibly  alter  the  colour  of 
gold,  but  it  renders  it  much  less  fusible. 
Neither  nitric  nor  nitro-muriatic  acid  acts 
on  it  in  either  of  these  alloys  :  but  if  it  be 
fused  with  three  parts  of  bismuth,  lead,  or 
copper,  the  alloy  is  entirely  soluble  in  a 
mixture  of  nitric  acid  with  two  parts  of 
muriatic. 

The  oxide  was  soluble  in  every  acid  Dr. 
Wollaston  tried.  The  solution  of  muria- 
tic acid  did  not  crystallize  by  evaporation 
Its  residuum  formed  a  rose-coloured  so- 
lution with  alcohol.  Murjat  of  ammonia 
and  of  soda,  and  nitrat  of  potash,  occa- 
sioned no  precipitate  in  the  muriatic  solu- 
tion, but  formed  with  the  oxide  triple  salts 
which  were  insoluble  in  alcohol.  Its  so- 
lution in  nitric  acid  likewise  did  not  crys- 
tallize but  silver,  copper,  and  other  me- 
tals precipitated  it. 

The  solution  of  the  triple  salt  with  mu- 
riat  of  soda,  was  not  precipitated  by  mu- 


riat,  carbonat,  or  hidrosulphuret  of  am- 
monia, by  carbonat  or  prussiat  of  potash, 
or  by  carbonat  of  soda.  The  caustic  al- 
kalies, however,  throw  down  a  yellow  ox- 
ide, soluble  in  excess  of  alkali ;  and  a  so- 
lution of  platina  occasions  in  it  a  yellow 
precipitate. 

The  title  of  this  product  to  be  consider- 
ed as  a  distinct  metal  has  been  question- 
ed ;  but  the  experiments  of  Dr.  Wollaston 
have  since  been  confirmed  by  Descotils. 

RHODIUM  LIGNUM,  Roie  iuood..-.A 
wood  or  root  brought  from  the  Canary 
islands,  and  confounded  with  aspalathus, 
a  simple,  of  considerable  esteem  among 
the  ancients,  but  which  has  not  come  to 
the  knowledge  of  latter  times. 

The  writers  on  botany  and  the  materia 
medica  are  much  divided  about  the  lig- 
num rhodium,  and  not  only  with  regard 
to  the  plant  which  affords  it,  but  likewise 
in  their  accounts  of  the  drug  itself.  This 
confusion  seems  to  have  arisen  from  aft 
opinion,  that  the  rhodium  and  aspalathus 
are  the  same ;  whence  different  woods 
brought  into  Europe  for  the  unknown  as- 
palathus, were  sold  again  by  the  name  of 
rhodium. 

As  to  aspalathus,  the  ancients  them- 
selves disagree ;  Dioscorides  requiring  by 
this  appellation  the  wood  of  a  certain 
shrub  freed  from  the  bark,  and  Galen  the 
bark  of  a  root.  At  present  we  have  no- 
thing under  this  name  in  the  shops.  What 
was  heretofore  sold  among  us  as  aspala- 
thus, were  pieces  of  a  pale-coloured  wood 
brought  from  the  East  Indies,  and  more 
commonly  called  calambour. 

The  lignum  rhodium  of  the  shops  is" 
usually  in  long  crooked  pieces,  full  of 
knots,  which,  when  cut,  appear  of  a  yel- 
low colour  like  box,  with  a  reddish  cast : 
the  largest,  smoothest,  most  compact,  and 
deepest  coloured  pieces  should  be  chosen; 
and  the  small,  thin,  or  pale  ones  rejected. 
The  taste  of  this  wood  is  slightly  bitter- 
ish, and  somewhat  pungent;  its  smell 
very  fragrant,  resembling  that  of  roses  : 
when  long  kept,  it  seems  to  lose  its  smell ; 
but  on  cutting,  or  rubbing  one  piece 
against  the  other,  it  smells  as  well  as  at 
first.  Distilled  with  water,  it  yields  an 
odoriferous  essential  oil,  in  very  small 
quantity.  Rhodium  is  at  present  in  es- 
teem only  upon  account  of  its  oil,  which, 
is  employed  as  a  high  and  agreeable  per- 
fume in  scenting  pomatums  and  the  like. 
It  is  likewise  said  to  be  much  employed 
by  rat  catchers,  either  to  entice  the  rat* 
to  the  traps,  or  to  cover  the  smell  left  by 
handling  them.  But,  if  we  may  reason 
from  analogy,  this  odoriferous  simple 
might  be  advantageously  applied  to  no- 
bler purposes ;  a  tincture  of  it  m  ale«hol» 


RIG 


RIG 


which  contains  in  small  volume  the  virtue 
of  a  considerable  quantity  of  the  wood, 
bids  fair  to  prove  a  serviceable  cordial, 
not  inferior  perhaps  to  any  thing-  of  this 
kind. 

RICE.  On  the  means  of  making  bread 
from  rice  alone.  From  the  Journal  des 
Sciences ,  des  Lettres,  et  des  Jlrts. 

The  art  of  making-  bread  from  rice, 
though  much  spoken  of,  seems  to  be  very 
little  understood.  In  Chomel's  Dictionary  it 
is  said,  that  bread  may  be  made  of  rice,  but 
there  is  no  account  of  the  means  by  which 
it  is  to  be  done.  The  book  called  La  Jlii- 
son  Jlustiquc  goes  rather  further ;  for,  it 
informs  us,  that  this  kind  of  bread  is  made 
by  mixing  together  the  flour  of  rye,  and 
that  of  rice.  The  first  of  these  books, 
therefore,  may  be  considered  as  saying 
nothing,  since  it  is  absolutely  impossible 
to  make  bread  of  the  flour  of  rice  (which 
is  harsh  and  dry,  like  sand  or  ashes)  by 
treating  it  in  the  manner  in  which  wheat 
flour  is  treated.  The  manner  of  using 
rice  flour  described  in  the  second  book, 
is  but  an  uncertain  remedy  in  case  or 
want;  for,  if  we  have  no  rye,  we  cannot, 
according  to  that  book,  make  use  of  rice 
flour  for  making  bread,  because  an  equal 
quantity  of  rye  flour  is  said  to  be  neces- 
sary for  that  purpose  ;  and  consequent  ly, 
in  countries  where  no  rye  is  grown,  it 
would  be  impossible  to  make  bread  of* 
rice,  however  great  the  want  of  bread 
might  be. 

The  first  thing  to  be  done  to  the  rice  is 
to  reduce  it  into  flour:  this  may  be  done 
by  grinding  it  in  a  mill,  or,  if  we  have  not 
a  mill,  it  may  be  done  in  the  following 
manner.  Let  a  certain  quantity  of  water 
be  heated  in  a  saucepan  or  cauldron  ; 
when  the  water  is  near  boiling,  let  the  rice 
we  mean  to  reduce  into  flour,  be  thrown 
into  it :  the  vessel  is  then  to  be  taken  off' 
the  fire,  and  the  rice  left  to  soak  till  the 
next  morning.  It  will  then  be  found  at 
the  bottom  of  the  water,  which  is  to  be 
poured  off,  and  the  rice  put  to  drain  upon 
a  table  placed  in  an  inclined  position. 
When  it  is  dry,  it  must  be  beat  to  pow- 
der, and  passed  through  the  finest  sieve 
that  can  be  procured. 

When  we  have  brought  the  rice  into 
flour,  we  must  take  as  much  of  it  as  may 
be  thought  necessary,  and  put  it  into  the 
kneading  trough  in  which  bread  is  gene- 
rally made.  At  the  same  time  we  must 
heat  some  water  in  a  saucepan,  or  other 
vessel,  and,  having  thrown  into  it  some 
handfuls  of  rice,  we  must  let  them  boil  to- 
gether for  some  time :  the  quantity  of  rice 
must  be  such  as  to  render  the  water  very 
thick  and  glutinous.  When  this  glutinous 
matter  is  a  little  cooled,  it  must  be  pour- 


ed upon  the  rice  flour,  and  the  whole 
must  be  well  kneaded  together,  adding 
thereto  a  little  salt,  and  a  proper  quantity 
of  leaven.  We  are  then  to  cover  the 
dough  with  warm  cloths,  and  to  let  it 
stand  that  it  may  rise.  During  the  fer- 
mentation, this  paste  (which,  when  knead- 
ed, must  have  such  a  proportion  of  flour 
as  to  render  it  pretty  firm)  becomes  so 
soft  and  liquid,  that  it  seems  impossible 
it  should  be  formed  into  bread  :  it  is  now 
to  be  treated  as  follows. 

While  the  dough  is  rising,  the  oven 
1  must  be  heated ;  and,  when  it  is  of  a  pro- 
per degree  of  heat,  we  must  take  a  stew- 
pan,  of  tin  or  copper  tinned,  to  which  is 
fixed  a  handle  of  sufficient  length  to  reach 
to  the  end  of  the  oven.  A  little  water 
must  be  put  into  this  stew-pan,  which 
must  then  be  filled  with  the  fermented 
paste,  and  covered  with  cabb  ige,  or  any 
other  large  leaves,  or  with  a  sheet  of  pa- 
per. When  this  is  done,  the  stew-pan  is 
to  be  put  into  the  oven,  and  pushed  for- 
ward to  the  part  where  it  is  intended  the 
bread  shall  be  baked;  it  must  then  be 
quickly  turned  upside  down.  The  heat 
of  the  oven  acts  upon  the  paste  in  such  a 
way  as  to  prevent  its  spreading-,  and  keeps 
it  in  the  form  the  stew-pan  has  given  it. 

In  this  manner  pure  rice  bread  may  be 
made  ;  it  comes  out  of  the  oven  of  a  fine 
yellew  colour,  like  pastry  which  has  yolk 
of  eggs  over  it.  It  is  as  agreeable  to  the 
taste  as  to  the  sight,  and  may  be  made  use 
of,  like  wheat  bread,  to  put,  into  broth, 
&c.  We  must,  however,  observe,  that  it 
loses  its  goodness  very  much  as  it  be- 
comes stale 

It  may  be  here  remarked,  that  the  man- 
ner in  which  Indian  corn  is  used  in  France 
for  making  bread,  can  only  produce  (and 
does  in  fact  produce)  very  bad  dough,  and 
of  course  very  bad  bread.  To  employ  it 
advantageously,  it  should  be  treated  like 
rice,  and  it  may  then  be  used,  not  only 
for  making  bread,  but  also  for  pastry. 

Rice  is,  in  the  opinion  of  Dr.  Cullen, 
preferable  to  all  other  grain,  both  for  its 
abundant  produce,  and  the  large  portion 
of  nutriment  it  affords.  Hence,  different 
methods  have  been  devised,  of  cooking  or 
dressing  it  in  the  most  economical  man- 
ner. Thus,  if  a  quarter  of  a  pound  of  rice 
be  tied  loosely  in  a  cloth  capable  of  hold- 
ing five  times  that  quantity,  and  then 
slowly  boiled,  it  will  produce  above  a 
pound  of  solid  food;  which,  eaten  with 
sugar,  or  boiled  milk,  forms  a  very  pala- 
table dish.  And,  if  an  egg,  together  with 
a  quarter  of  a  pint  of  milk,  a  small  quan- 
tity of  sugar,  and  grated  nutmeg  be  add- 
ed, it  will  afford  a  more  agreeable  pud- 
ding than  those  prepared  either  of  wheat- 


ROA 


ROA 


en  flour  or  bread.  One  of  the  best  prepa- 
rations of  this  grain,  however,  especially 
for  invalids,  is  its  mucilage  or  jelly;  which 
may  be  obtained  by  boiling"  two  ounces  of 
fine  rice  flour  with  a  quarter  of  a  pound 
of  lump  sugar,  in  a  pint  of  water,  till  it 
become  an  uniform  gelatinous  mass  :  on 
being  strained  through  a  cloth,  and  suf- 
fered to  cool,  it  constitutes  a  salubrious 
and  nourishing  food. 

ROASTING  OF  ORE.    See  Ore. 

ROASTING,  an  operation  of  cookery. 
Without  troubling  our  readers  with  unne- 
cessary remarks,  we  shall  here  make  a 
few  extracts  from  Count  Rum  ford's  work 
on  this  subject-  By  a  reference  to  that 
work,  cuts  of  the  roasting  machine  may 
be  seen.  The  Count  observes,  that  "  no 
process  of  cookery  is  more  troublesome, 
or  attended  with  a  greater  waste  of  fuel, 
than  roasting  meat  before  an  open  fire. 
Having  had  occasion  to  fit  up  a  hu  ge 
kitchen,  for  the  military  academy  at  Mu- 
nich, 1  was  led  to  consider  this  subject 
with  some  attention,  and  I  availed  myself 
of  the  opportunity  which  then  offered,  to 
make  a  number  of  experiments,  from 
which  I  was  enabled  to  construct  a  ma- 
chine for  roasting,  which  upon  trial,  was 
found  to  answer  so  well,  that  I  thought  it 
deserving  of  being  made  known  to  the 
public  ;  accordingly,  I  caused  two  roast- 
ers to  he  constructed  in  London,  one  at 
the  house  then  occupied  by  the  Board  of 
Agriculture,  and  the  other  at  the  Found, 
ling  Hospital,  and  a  third  was  ptit  up,  in 
Dublin,  at  the  house  of  the  Dublin  Society. 
All  these  were  found  to  answer,  and  they 
were  often  imitated.  Meat  roasted  by  this 
new  process,  is  more  delicate,  more  juicy, 
and  higher  flavoured,  than  when  roasted 
on  a  spit  before  an  open  fire.  Many 
roasters  have  been  put  up  in  the  houses 
of  persons  of  the  highest  rank;  others  in 
the  kitchens  of  artificers,  of  public  schools, 
taverns,  and  other  houses  of  public  resort, 
and  the  use  of  them  has  been  found  to  be 
economical,  and  advantageous  in  all  re- 
spects. The  body  of  the  roaster  is  a  hol- 
low cylinder  of  sheet  iron,  which,  for  a 
roaster  of  a  moderate  size,  may  be  made 
about  18  inches  in  diameter,  and  24  inches 
long;  closed  at  one  end,  and  set  in  an 
horizontal  position  in  a  mass  of  brick 
work,  in  such  a  manner  that  the  flame  of 
a  small  fire,  made  in  a  closed  fire  place 
directly  under  it,  may  play  all  round  it, 
and  heat  it  equally  and  expeditiously.  The 
open  end  of  this  cylinder,  which  should  be 
even  with  the  front  of  the  brick  work  in 
which  it  is  set,  is  closed  either  with  a  dou- 
ble door  of  sheet-iron,  or  with  a  door  of 
sheet-iron,  covered  on  the  outside  with  a 
panne!  of  wood;  and  in  the  cylinder,  there 


is  an  horizontal  shelf,  made  of  a  flat  plate 

of  sheet  iron,  supported  on  ledges  rivetted 
to  the  inside  of  the  cylinder,  on  each  side 
of  it.  This  shelf  is  situated  about  three 
inches  below  the  centre,  or  level  of  the 
axis  of  the  roaster,  and  serves  as  a  sup- 
port for  a  dripping  pan,  in  which,  or  ra- 
ther over  which,  the  meat  to  be  roasted, 
is  placed. 

This  dripping-pan,  is  made  of  sheet- 
iron,  and  is  about  two  inches  deep,  16 
inches  wide  above,  15  1-4  inches  in  width 
below,  and  22  inches  long,  and  is  placed 
on  four  short  feet,  or  what  is  better,  on 
two  long  sliders,  bent  upwards  at  their 
extremities,  and  fastened  to  the  ends  of  the 
dripping-pan,  forming,  together  with  the 
dripping-pan,  a  kind  of  sledge  ;  the  bottom 
of  the  pan  being  raised  by  these  means, 
about  an  inch  above  the  horizontal  shelf 
on  which  it  is  supported.  In  order  that 
the  pan,  on  being  pushed  into,  or  drawn 
out  of  the  roaster,  may  be  made  to  pre- 
serve its  direction,  two  straight  grooves 
are  made  in  the  shelf  on  which  it  is  sup- 
ported, which,  receiving  the  sliders  of  the 
dripping-pan,  prevent  it  from  slipping 
about  from  side  to  side. 

In  the  dripping-pan  a  gridiron  is  placed, 
the  two  bars  of  which  are  on  a  level  with 
the  sides  or  brim  of  the  dripping-pan,  and 
on  this  gridiron  the  meat  to  be  roasted  is 
laid;  care  being  taken,  that  there  be  al- 
ways a  sufficient  quantity  of  water  in  the 
dripping-pan  to  cover  the  whole  of  its  bot- 
tom to  the  height  of  at  least  half  or  three 
quarters  of  an  inch,  for  the  parpose  of  re- 
ceiving the  drippings  of  the  meat. 

Mr.  Frost,  of  Norwich,  places  a  second 
shallow  pan,  made  of  tin,  and  standing  on 
four  short  feet,  into  the  first,  and  then 
places  the  gridiron  which  is  to  support 
the  meat,  in  this  second  dripping-pan.  As 
the  water  in  the  first  keeps  the  second 
cool,  there  is  no  necessity  for  putting  wa- 
ter into  this ;  and  the  drippings  of  the 
meat,  may,  without  danger,  fall  into  it. 
When  Yorkshire  puddings,  or  potatoes, 
are  cooked  under  roasting  meat,  this  ar- 
rangement will  be  found  very  convenient. 

The  second  dripping-pan  must  not 
touch  the  first,  except  by  the  ends  of  its 
feet;  the  bottom  of  the  second  must  also 
be  dear  of  the  bottom  of  the  first.  The 
lengths  and  widths  of  the  two  pans  above, 
or  at  their  brims,  may  be  equal,  and  the 
brim  of  the  second  may  stand  half  an  inch 
above  the  level  of  the  brim  of  the  first. 
The  horizontal  level  of  the  upper  surface 
of  the  gridiron,  should  not  be  lower  than 
the  level  of  the  brim  of  the  second  drip- 
ping-pan ;  and  the  meat  should  be  so 
placed  on  the  gridiron,  that  the  drippings 
from  it  cannot  fail  to  fail  into  the  pan,  and 


ROA 


HOA 


never  upon  the  hot  bottom,  or  sides  of  the 
roaster. 

To  carry  off  the  steam  which  arises 
from  the  water  in  the  dripping-pan,  and 
that  which  escapes  from  the  meat  in 
roasting,  there  is  a  steam  tube  belonging 
to  the  roaster,  which  is  situated  at  the  up- 
per part  of  the  roaster,  commonly  a  little 
on  one  side,  and  near  the  front  of  it,  to 
which  tube  there  is  a  damper  so  contriv- 
ed, as  to  be  easily  regulated  without 
opening  the  door  of  the  roaster. 

The  heat  of  the  roaster  is  regulated  at 
pleasure,  by  means  of  the  register  in  the 
ash-pit  door  of  its  fire  place,  and  by  the 
damper  in  the  canal,  by  which  the  smoke 
goes  off  into  the  chimney. 

The  dryness  in  the  roaster  is  regulated 
by  the  damper  of  the  steam  tube,  and  also 
by  means  of  the  blow  pipes. 

These  blow  pipes,  which  lie  immediate- 
ly under  the  roaster,  are  two  tubes  of  cast 
iron,  about  2  1-2  inches  in  diameter,  and 
23  inches  long,  or  about  one  inch  shorter 
than  the  roaster ;  which  tubes,  by  means 
of  elbows  at  their  farther  ends,  are  firmly 
fixed  to  the  bottom  of  the  roasters,  and 
communicate  with  the  inside  of  it.  The 
higher  ends  of  these  tubes  come  through 
the  brick  work,  and  are  seen  in  front  of 
the  roaster,  being  even  with  its  face. 
These  blow  pipes  have  stoppers,  by  which 
they  are  accurately  closed ;  but  when  the 
meat  is  to  be  browned,  these  stoppers  are 
removed,  or  drawn  out  a  little,  and  the 
damper  in  the  steam  tube  of  the  roaster 
being  at  the  same  time  opened,  a  strong 
current  of  hot  air  presses  in  through  the 
tubes  into  the  roaster,  and  through  the 
roaster  into,  and  through  the  steam  tube, 
carrying  and  driving  away  all  the  moist 
air  and  vapour  out  of  the  roaster.  The 
hot  wind  blowing  over  the  meat,  causes 
that  appearance  and  taste,  which  are  pe- 
culiar to  meat  well  roasted. 

Directions  for  Roasters. 
1.  The  fire  place  must  be  made  very 
small.    2.  Provision  must  be  made  for 
cleaning  the  flues  when  obstructed  by 
soot. 

For  a  roaster  18  inches  wide,  and  24 
inches  long,  the  fire  place  should  be  7 
inches  wide,  and  9  inches  long;  and  the 
side  walls  of  the  fire  place  should  be  quite 
vertical  to  the  height  of  6  or  7  inches. 
The  quantity  of  fuel  requisite  is  incredi- 
bly small.  A  fire  place  of  the  above  di- 
mensions will  contain  coals  enough  to 
heat  the  roaster,  and  many  more  than 
will  be  necessary  for  keeping  it  hot  when 
heated. 

The  soot  flues  may  be  4  or  5  inches 
square,  in  the  brick  work,  to  introduce  a 


brush  like  a  bottle  brush  with  alonghan* 
die ;  which  openings  may  be  closed  with 
stoppers  or  fit  pieces  of  brick  or  stone, 
and  the  joinings  made  good  with  a  little 
clay.  The  stoppers  may  have  a  small 
iron  ring  or  handle. 

A  simple  contrivance  is  used  for  the 
purpose  of  removing  the  soot,  which  is 
apt  to  collect  about  the  top  of  a  roaster. 
By  means  of  an  oblong  square  frame  con- 
structed of  sheet  iron,  and  fastened  to  the 
top  of  the  roaster  by  rivets,  a  door  way  is 
opened  into  the  void  space  left  for  the 
flame  and  smoke  between  the  outside  of 
the  roaster  and  the  hollow  arch  or  vault 
in  which  it  is  placed  ;  and  by  introducing 
a  brush  with  a  flexible  handle  through 
this  door  way,  the  soot  adhering  to  the 
outside  of  the  top  of  the  roaster,  and  to 
the  surface  of  the  brick  work  surround- 
ing it,  may  be  detached  and  made  to  fall 
back  into  the  fire  place,  whence  it  may 
be  removed  with  a  shovel. 

There  should  always  be  a  passage,  or 
throat  of  a  certain  Length  between  the 
mouth  or  door  of  a  closed  fire  place,  and 
the  fire  place  properly  called,  or  the  ca- 
vity occupied  by  the  burning  fuel.  Where 
fire  places  are  of  large  dimensions,  it  is 
very  useful  to  keep  tins  throat  constantly 
filled  with  coal,  which  not  burning,  serves 
to  defend  the  door  from  the  heat  of  the 
lire ;  and  being  well  warmed,  inflames 
quickly. 

In  constructing  closed  fire  places,  for 
roasters,  boilers,  ovens,  &c,  it  has  been 
found  to  be  a  good  rule  to  make  the  dis- 
tance between  the  fire  place  door,  and  the 
hither  end  of  the  bars  of  the  grate  equal 
to  the  width  of  the  fire  place,  measured 
just  above  the  bars.  In  fire  places  of  a 
moderate  size,  where  doubie  doors  are 
used,  it  will  suffice,  if  the  distance  from 
the  hinder  side  of  the  inner  door,  to  the 
hither  end  of  the  bars,  be  made  equal  to 
the  width  of  a  brick,  or  4  1-2  inches  ;  but 
if  the  door  be  single,  it  is  necessary  that 
the  length  of  the  passage  from  the  door, 
into  the  place  occupied  by  the  burning 
fuel,  should  be  at  least  6  or  7  inches. 

By  taking  away  a  laige  flat  stone,  or 
a  twelve  inch  tile,  placed  edgeways,  a 
passage  may  be  opened  occasionally,  in 
order  to  clean  out  the  canals,  and  remove 
the  soot.  The  steam  tube  must  open  into 
a  separate  canal,  which  must  be  construct- 
ed for  the  sole  purpose  of  carrying  oft*  the 
steam  into  the  chimney,  or  into  the  open 
air.  The  steam  tube  must  be  laid  on  a 
descent,  to  convey  oft'  the  condensed  va- 
pour. 

Some  care  will  be  necessary  in  forming 
the  vault,  which  is  to  cover  the  roaster 
above.   Its  form  should  be  regular,  in  or- 


ROA 


ROA 


«ier  that  it  may  be  every  where  at  the 
same  distance  from  the  roaster  ;  and  its 
concave  surface,  should  be  as  even  and 
smooth  as  possible,  in  order  that  there 
may  be  the  fewer  cavities,  for  the  lodge- 
ment of  soot.  The  distance  between  the 
outside  of  the  roaster,  and  the  concave 
surface  of  the  vault,  may  be  about  two  in- 
ches ;  and  the  same  distance  may  be  pre- 
served below,  between  the  brick-work  and 
the  sides  of  the  roaster. 

Directions  for  the  Management  of  a  Roas- 
ter, 

1.  Keep  the  roaster  clean. 

2.  Prevent  the  meat  from  touching-  the 
sides,  and  the  gravy  from  spilling-.  When 
grease-spots  appear,  the  inside  of  the 
roaster  must  be  washed,  first  with  soap 
and  water,  then  with  pure  water,  to  take 
away  the  soap,  and  wiped  very  dry. 

3.  The  fire  must  be  moderate ;  about 
one-third  more  time  is  required,  than  to 
roast  in  the  usual  way. 

4.  The  blow-pipes  must  be  closed,  from 
the  time  the  meat  goes  in,  till  within  12 
or  15  minutes  of  its  being  sufficiently 
done,  that  is,  till  it  is  to  be  browned  ; 
which  is  effected  in  the  following  way  : 
the  fire  is  made  to  burn  bright  and  clear, 
for  a  few  minutes,  till  the  blow -pipes  be- 
gin to  redden ;  (which  may  be  seen  by 
withdrawing  their  stoppers  for  a  moment, 
and  looking  into  them)  when  the  damper 
of  the  steam-tube  of  the  roaster  being 
opened,  and  the  stoppers  of  the  blow- 
pipes drawn  out,  a  certain  quantity  of  air 
is  permitted  to  pass  through  the  heated 
blow-pipes,  into,  and  through  the  roaster. 
The  quantity  of  air  necessary  to  be  ad- 
mitted, must  depend  upon  the  trim  of  the 
roaster,  which  will  soon  be  discovered  by 
the  cook. 

The  damper  of  the  steam-tube  must  be 
kept  so  much  opened,  that  the  steam  from 
the  meat  and  water,  may  not  be  seen  com- 
ing out  of  the  roaster,  through  the  crevi- 
ces of  the  door. 

In  brightening  the  fire,  fresh  coals  must 
not  be  put  in,  but  a  small  faggot  of  dry 
wood,  or  a  little  bundle  of  dry  wood,  split 
into  small  pieces.  Indeed,  wood  is  a  pre- 
ferable fuel  to  coals,  for  roasters.  When 
the  door  of  the  roaster  is  to  be  opened, 
the  steam -tubes  and  blow-pipes,  must  be 
first  opened  about  a  quarter  of  a  minute, 
to  drive  away  the  steam. 

To  keep  meat  warm,  when  done,  be- 
fore it  is  sent  to  table  ;  close  the  register 
of  the  ash-pit  door,  open  the  fire-place 
door,  and  damper  in  the  chimney ;  take 
out  the  fire,  or  cover  it  with  cold  ashes, 
and  lastly,  open  the  dampers  in  the  steam- 
and  blow-pipes.   When  the  heat  is  mo- 


derated sufficiently,  the  blow -pipes  and 
the  damper  in  the  steam-tube,  may  be 
nearly  closed ;  and  if  there  be  danger  of 
the  cooling  being  carried  too  far,  the  fire- 
place door  may  be  shut. 

The  door  may  be  made  a  little  dishing, 
to  prevent  its  warping,  and  should  never 
shut  into  grooves,  but  close  tight,  by 
causing  the  flat  surface,  of  the  inside  of 
the  door  to  lay  against,  and  touch  in  all 
parts,  the  front  edge  of  the  door-frame  : 
which  front  edge  must  of  course  be 
made  perfectly  level,  and  as  smooth  as 
possible. 

If  the  front  end  of  the  cylinder  of  sheet- 
iron,  which  forms  the  body  of  the  roaster, 
be  turned  outwards  over  a  very  stout  iron 
wire,  (about  one-third  of  an  inch  in  diame- 
ter, for  instance)  this  will  strengthen  the 
roaster  very  much,  and  render  it  easier  to 
make  the  end  of  the  roaster  level,  to  re- 
ceive this  flat  surface  of  its  door;  it  can 
most  easily  be  made  level,  by  placing  the 
cylinder  in  a  vertical  or  upright  position, 
with  its  open  end  downwards,  on  a  flat 
anvil,  and  hammering  the  wire  above- 
mentioned,  till  its  front  edge,  which  re- 
poses on  the  anvil,  is  quite  level. 

In  order  that  the  roaster  may  close  well, 
its  hinges  should  be  made  to  project  out- 
wards, beyond  the  sides  of  the  roaster  ; 
and  it  should  be  fastened,  not  by  a  com- 
mon latch,  but  by  two  turn-buckles,  si- 
tuated just  opposite  to  the  two  hinges, 
and  consequently  the  distance  the  two 
turn-buckles  should  be  placed  from  each 
other,  should  be  equal  to  half  the  diame- 
ter of  the  roaster. 

The  hooks  for  the  hinges,  and  also  the 
support  for  the  two  turn-buckels,  should 
be  situated  at  the  projecting  em's,  of 
strong  iron  straps,  fastened  at  one  of  their 
ends,  to  the  outside  of  the  roaster,  by 
means  of  ri vetting  nails. 

The  door  may  be  constructed  of  a  sin- 
gle sheet  of  iron,  and  covered  on  the  out- 
side with  a  pannel  of  wood,  not  a  board  ; 
or  it  may  be  constructed  of  two  sheets  of 
iron  placed  parallel  to  each  other,  at  the 
distance  of  about  an  inch,  and  so  fastened 
together,  that  the  air  between  them  may 
be  confined. 

This  pannel  consists  of  a  square  frame 
tenanted,  and  fastened  together  at  each, 
of  its  four  corners  with  a  single  pin  ;  and 
filled  up  in  the  middle  with  a  square  board 
or  pannel,  which  is  confined  in  its  place, 
by  being  made  to  enter  into  deep  grooves 
or  channels,  in  the  insides  of  the  pieces 
Which  form  the  frame.  The  circular  iron 
door  to  which  the  pannel  is  fixed,  being 
covered  and  concealed  from  view  by  the 
wood,  but  its  size  and  position  are  mark- 
ed out  by  a  dotted  circle  ;  and  the  heads 


ROA 


ROA 


<>f  ten  rivets  are  seen,  by  which  the  wood- 
en pannel  is  fastened  to  the  iron  door 
These  rivets  are  made  to  hold  the  wood 
fast  to  the  iron,  by  means  of  small  circu- 
lar plates  of  sheet  iron. 

The  frame  of  the  pannel  consits  of  four 
pieces  of  common  deal,  four  inches  wide, 
and  one  inch  thick,  fastened  with  one  pin 
only  at  each  of  their  joining's  at  the  cor- 
ners, and  these  pins  being-  situated  in  the 
centre  of  those  joinings,  it' upon  the  frame, 
in  the  middle  of  each  of  the  four  pieces 
which  comoose  it,  a  square  be  drawn  in 
such  a  manner,  that  the  corners  of  this 
square,  may  coincide  with  the  centres  of 
the  four  pins,  which  hold  the  frame  toge- 
ther, as  neither  heat  nor  dryness  makes 
any  considerable  alteration  in  the  length 
of  the  fibres  of  wood,  it  is  evident  that  the 
shrinking  of  the  four  pieces,  which  com 
pose  this  frame,  cannot  alter  the  dimen- 
sions of  this  square,  or  in  any  way  change 
its  position.  If,  therefore,  care  be  taken 
in  fastening  the  pannel  to  the  iron  door, 
to  place  the  riveting-nails,  in  the  lines 
which  form  the  four  sides  of  this  square, 
the  shrinking  of  the  wood,  will  occasion 
no  strain  on  the  iron  door,  nor  have  any 
tendency  whatever  to  change  its  form  ; 
and  with  regard  to  the  centre  piece  Ot'the 
pannel,  if  it  be  fastened  to  the  iron  by  two 
rivets,situated  in  the  direction  of  the  fibres 
of  the  wood,  in  a  line  dividing  this  piece 
into  two  eqnal  parts,  its  shrinking  will  be 
attended  with  no  kind  of  inconvenience. 
Care  must  be  taken  to  make  this  pannel 
enter,  so  deeply  into  the  grooves  in  its 
frame,  that  when  it  is  shrunk  as  much  as 
possible,  its  width  shall  not  be  so  much 
reduced,  as  to  cause  it  to  come  quite  out 
of  the  grooves.  This  piece  may  be  made 
about  one-third  of  an  inch  thick ;  and  the 
grooves  which  receive  it,  may  be  made  of 
the  same  width,  and  about  three  quarters 
of  an  inch  thick. 

Cartridge-paper  soaked  in  alum -water, 
is  to  be  interposed  between  the  iron  door 
and  wooden  pannel,  to  prevent  the  wood 
being  set  on  fire,  from  the  heat  of  the  iron: 
and  each  of  the  two  rivets  which  pass 
through  the  centre  piece  of  wood  in  the 
door,  must  also  pass  through  a  small 
block  of  wood,  about  an  inch  thick,  which 
wiil  give  these  rivets  a  proper  bearing, 
without  any  strain  to  the  iron  door.  The 
hinges  are  to  be  riveted  to  the  outside 
surface  of  the  circular  iron  door,  and  let 
into  the  wood.  The  turn-buckles  must 
be  made  to  press  against  the  outside  or 
front,  of  the  wooden  frame. 

Of  the  Blow-pipes. 
They  should  be  of  cast-iron,  with  flan- 
dies,  and  keyed  on  the  inside  of  the  roas- 


|  ter ;  and  their  joinings  with  the  bottom 
j  of  the  roaster,  must  be  made  tight  with 
some  cement  that  will  stand  fire.  A  small 
quantity  of  iron-wire,  put  into  the  tubes, 
will  increase  their  effect. 

Of  the  Steam-tube. 
It  should  be  situated  any  where  in  the 
upper  part  of  the  roaster.  The  simplest 
damper  is  a  circular  plate  of  iron,  a  very 
little  less  in  diameter  than  the  tube,  in 
which  it  moves  on  an  axis,  perpendicular 
to  the  axis  of  the  tube.  This  axis  being- 
prolonged,  comes  forward  through  the 
brick-work. 

Of  the  Dripping -pan. 

It  should  be  hammered  out  of  one  piece 
of  sheet-iron;  and  a  little  shorter  than 
the  roaster ;  room  must  be  left  between 
the  farther  end  of  it,  and  the  farther 
end  of  the  roaster,  for  the  hot  air 
from  the  blow-pipes,  to  pass  up  into 
the  upper  part  of  the  roaster.  It  should 
have  two  falling  handles,  one  at  each  end, 
with  stops  to  hold  them  fast. 

To  defend  the  bottom  of  the  roaster 
from  excessive  heat,  it  occurred  to  me  to 
use  a  shallow  iron  pan  turned  upside 
down,  with  a  row  of  holes  from  side  to 
side,  at  the  farther  end  of  it ;  and  this  in- 
vention was  found  to  answer  very  well. 

Roasting  Ovens. 

The  general  form  of  the  front  of  the 
oven  is  circular ;  but  it  has  two  projec- 
tions on  opposite  sides  of  it,  to  one  of 
which  the  hinges  of  the  door,  and  to  the 
other  the  turn-buckles  for  fastening  it 
when  closed,  are  fastened.  It  has  ano- 
ther projection  above,  which  serves  as  a 
frame  to  the  door-way,  through  which  a 
brush  is  occasionally  introduced  for  the 
purpose  of  cleaning  the  flues.  On  one 
side  of  this  projection  there  is  a  small  hole, 
through  which  the  handle  or  projecting 
axis  of  the  circular  register  of  the  vent- 
tube,  (wich  is  not  seen,)  passes. 

In  the  body  of  the  oven,  at  the  distance 
of  half  its  semi-diameter,  below  its  cen- 
tre or  axis,  there  is  an  horizontal  shelf, 
which  is  fixed  in  its  place,  not  by  resting 
on  ledges,  but  by  its  hither  end  being" 
turned  down,  and  firmly  riveted  to  the 
vertical  plate  of  iron,  which  I  call  the  front 
of  the  oven.  This  shelf,  which  should  be 
double,  to  prevent  the  heat  from  passing 
through  it  from  below,  must  not  reach 
quite  to  the  farther  end  of  the  oven  ;  there 
must  be  an  opening  left,  about  one  inch  in 
width,  between  the  end  of  it  and  the  far- 
ther end  of  the  oven,  through  which  open- 
ing the  air  heated  below  the  shelf,  will 


I10A 


JiOC 


make  its  way  into  the  upper  part  of  the 

oven. 

'[  he  hollow  space  below  the  shelf,  is 
intended  to  serve  in  place  of  the  blow- 
pipes of  a  roaster;  and  this  office  it  will 
perform  tolerably  well,  provided  means 
are  used  for  admitting-  cold  air  into  it, 
occasionally.  This  is  done  by  means  of 
a  register,  situated  at  the  lower  part  of 
the  vertical  front  of  the  roaster,  a  little 
below  the  bottom  of  the  door. 

The  cylinder  constituting  the  bottom  of 
the  oven"  is  two  feet  long,  and  is  supposed 
to  be  of  cast-iron.  It  is  cast  with  a  ranch, 
which  projects  outwards,  about  one  inch 
at  the  opening  of  the  cylinder,  by  means 
of  which  flanch  it  is  attached,  by  rivers,  I 
to  the  front  of  the  oven,  which,  as  I  have 
already  observed,  must  be  made  of  strong- 
sheet  "iron,  near  one-eighth  of  an  inch  in 
thickness. 

The  shelf,  dripping  pan,  and  double 
door  might  easily  be  made  of  cast-iron  ; 
and  in  case  the  shelf  to  save  trouble  of 
riveting,  in  making  it  double,  may  be  co- 
vered by  an  inverted  shallow  pan,  of  cast- 
iron,  and  in  the  bottom  of  this  pan,  there 
may  be  cast  two  shallow  grooves,  both  in 
the  direction  of  the  length  of  the  pan,  and 
about  an  inch  from  the  sides,  in  which 
grooves,  two  parallel  projections,  at  a  pro- 
per distance  from  each  other,  cast  to  the 
bottom  of  the  lower  pan,  may  pass.  These 
projections  passing  freely  in  the  grooves 
which  receive  them,  will  serve  to  keep 
the  dripping  pan  steady,  in  its  proper  di- 
rection, when  it  is  pushed  into,  or  drawn 
out  of  the  oven. 

To  increase  the  effects  of  the  air  cham- 
ber, when  this  oven  is  used  for  roasting 
meat,  a  certain  quantity  of  iron  wire,  in 
loose  coils,  or  of  iron  turnings,  may  be 
put  into  the  air  chamber. 

The  door  of  the  oven,should  be  about  19 
inches  in  diameter  within,  or  in  the  clear. 

in  fastening  the  vertical  plate,  which 
forms  the  front  of  the  oven,  to  the  pro- 
jecting flanch,  at  the  hither  end  of  the 
oven,  care  must  be  taken,  to  beat  down 
the  heads  of  the  riveting  nails  in  front, 
otherwise  they  will  prevent  the  door  of 
the  oven  from  closing,  with  that  nicety 
which  is  requisite. 

In  setting  this  roasting  oven,  the  whole 
of  the  thickness  of  the  vertical  front, 
should  be  made  to  project  forward  be- 
fore the  brick-work.  The  fire-place,doors, 
ash-pit,  register-door,  damper  in  the  chim- 
ney, Sec.  should  be  in  all  respects,  similar 
to  those  used  for  roasters  ;  and  the  flues 
should  likewise  be  constructed  in  the 
same  manner." 

HOCK  OIL.     See  Petroleum,  Bi- 
tumen. 
VOL.  II. 


POCK  SALT.    See  Salt. 

KOGKETS.  In  the  art  of  making  fire- 
works, gunpowder  constitutes  the  chief 
ingredient;  but  the  proportion  of  it,  is 
very  frequently  varied,  according  to  the 
different  uses  for  which  it  is  intended. 
For  making  rockets,  meal-powder  only,  is 
commonly  employed,  and  mixed  with  an 
additional  quantity  of  sulphur  and  nitre, 
according  to  the  different  purposes  for 
which  they  are  designed  ;  on  which  ac- 
count, the  last  ingredient  is  generally 
brought  into  the  form  of  a  powder,  by  so- 
lution and  evaporation,  during  which  lat- 
ter operation,  it  is  continually  stirred. 

The  mechanical  operations  of  the  above- 
mentioned,  are  not  belonging  to  this  work, 
we  shall  only  make  mention  of  the  differ- 
ent compositions,  which  are  to  be  made 
upon  chemical  principles,  as  laid  down  by 
Wiegleb.  For  fuses,  seven  parts  of  meal- 
powder,  five  of  nitre,  and  three  of  sulphur; 
and  for  rockets,  thirty-six  parts  of  nitre, 
eight  of  sulphur,  and  fourteen  of  char- 
coal, are  to  be  taken  in  both  these,  the 
intention  is,  that  the  powder  shall  only  be 
fired  by  degrees.  For  blue-balls  are  to 
be  mixed  together,  thirteen  parts  of  nitre, 
three  of  sulphur,  seventeen-thirty-second 
parts  of  resin,  seven-sixteenths  of  saw- 
dust, and  nine-sixteenths  of  charcoal. — 
Light-balls  require  for  the  dry  sort,  two 
parts  of  nitre,  one-half  part  of  sulphur, 
three-sixteenths  of  resin,  two-thirds  of 
saw-dust,  and  one-half  part  of  meal-pow- 
der ;  for  the  fusible,  eight  parts  of  sulphur, 
two  of  nitre,  and  four  of  meal-powder. 
Fire-balls  are  composed  of  twenty  parts 
of  corned  powder,  ten  of  pitch,  six  of  ni- 
tre, four  of  sulphur,  one  of  tallow,  one  of 
hemp,  and  two  of  linseed-oil.  Water- 
rockets  require  eight  parts  of  meal-pow- 
der, thirty-six  of  nitre,  seven  of  sulphur, 
and  one  of  resin.  As  these  particular 
masses  of  fire,  are  destined  to  resist  the 
air  and  water,  and  nevertheless  to  burn 
for  a  certain  time,  the  oleaginous  and 
combustible  additions  are  requisite,among 
which,  the  intent  of  the  saw-dust  appears 
to  be,  to  prolong  the  conflagration.  Among 
these,  also  may  be  reckoned  the  Greek  ■ 
fire,  which  in  fact  was  not  invented  by  a 
Greek,  but  by  Callinicus  of  Helipolis,  who 
is  said  to  have  used  it,  at  the  siege  of 
Constantinople.  It  cannot  be  decided 
with  certainty,  what  it  properly  was,  or 
of  what  it  was  composed.  According  to 
the  description  of  it  given  in  history,  it 
was  a  liquid  substance,  that  was  easily 
kindled,  and  extinguished  with  difficulty, 
which  burned  upon  water,  and  was  thrown 
enclosed  in  bottles  and  pitchers,  into  the 
enemies'  ships,  by  which  means  they  were 
set  on  fire.  It  is  very  probable,  that  pitchy 
T  t 


ROS 

sulphur,  linseed-oil,  oil  of  turpentine,  or  I 
petroleum,  made  a  considerable  part  of  its 
composition. 

The  variously  coloured  fire-works,  de- 
pend on  various  additions,  by  which  the 
natural  colour  of  gun-powder,  when  on 
fire,  may  be  altered,  and  in  which  metal- 
lic substances  for  the  most  part,  such  as 
antimony,  zinc,  niarcasite,  verdigrise,  &c- 
are  employed.  Thus  also,  clean  filings 
of  iron  produce  what  is  called  brilliant, 
or  white  fire. 

ROMAN  VITRIOL.    See  Copper. 

ROSE  WATER.  See  Distilled 
Waters. 

ROSE  OIL.    See  Oil. 

ROSEMARY  OIL.    See  Oil. 

ROSIX,  or  more  properly  Resin. 

This  term  is  given  to  a  very  important 
class  of  vegetable  substances,  of  which 
there  is  a  great  variety  of  species,  differ- 
ing from  each  other  in  consistence,  co- 
lour, smell,  and,  in  some  degree,  in  chemi- 
cal composition. 

The  origin  of  all  the  resins  is  the  same, 
that  is,  they  exude  spontaneous!}',  or  are 
extracted  by  incisions  made  in  the  bark 
of  the  resinous  trees,  and  most  of  them 
gradually  harden  by  exposure  to  air.  A 
further  portion  of  the  same  resin  may 
also  be  always  extracted  artificially  from 
the  tree  that  yields  it,  by  chemical  me- 
thods. Resin  is  also  very  generally  met 
with  in  certain  parts  of  vegetables,  though 
its  quantity  is  so  small,  or  its  combination 
witfrVJther  constituent  parts  is  so  strong, 
as  not  to  appear  in  its  proper  form  till  ex- 
tracted by  chemical  analysis.  Thus,  the 
bark  of  the  cinchona  contains  no  inconsi- 
derable quantity  of  resin,  though  none  ap- 
pears to  the  eye  on  mere  inspection,  or 
(probably)  could  be  extracted  by  incision 
through  the  living  tree. 

The  chemical  properties  which  are 
usually  understood  to  characterize  a  re- 
sin, are  the  following  :  it  is  first  softened 
and  then  melted  by  heat,  and  when  kin- 
dled, it  burns  readily  with  a  strong  and 
generally  fragrant  smell,  with  copious 
flame  and  smoke,  and  leaves  scarcely  any 
residue  behind.  It  is  insoluble  in  water 
and  most  watery  liquids,  and  is  not  easily 
acted  on  by  acids  or  alkalies,  except  they 
are  concentrated,  and  the  action  assisted 
by  heat  or  long  digestion.  But  it  readily 
and  totally  dissolves  in  alcohol,  forming  a 
clear,  but  coloured  solution,  from  which 
by  far  the  greater  part  of  the  resin  is  pre- 
cipitated in  a  pulverulent  form  unaltered, 
by  the  addition  of  water,  which  imme-l 
diately  renders  the  solution  opake  and 
turbid.    It  is  also  soluble  in  sulphuric 


110S 

ether,  and  in  the  fixed  and  volatile  oils  ; 
particularly  the  latter. 

But  though  all  resins  agree  in  the  qua- 
lities of  inflammability,  insolubility  in  wa- 
ter, and  solubility  in  alcohol,  there  are  se- 
veral other  circumstances  which  have 
usually  been  employed  to  distinguish  the 
classes  of  resins. 

Balsams,  according  to  the  ancient  sense 
of  the  word,  was  certainly  applied  simply 
to  those  resins  that  always  remained  in  a 
fluid  or  semi-fluid  state,  such  as  the  bal- 
sam of  Capivi,  of  Mecca,  of  Canada,  &.c  ; 
and  these  appear  to  be  resins  holding  a 
superabundance  of  essential  oil,  so  that 
when  distilled  per  se,  a  vast  quantity  of 
oil  arises,  and  a  hard  brittle  resin  is  left 
behind,  if  the  heat  employed  is  only  mo- 
derate. Thus  turpentine,  which  is  a,  na- 
tural balsam,  yields  by  distillation  abun- 
dance of  the  essential  oil  of  turpentine, 
and  common  robin  (which  is  a  true  resin) 
is  left  behind. 

The  term  balsam,  however,  has  of  late 
been  injudiciously  applied  in  the  modern 
chemical  nomenclature  to  those  two  or 
three  species  of  resins  that  contain  a  no- 
table quantity  of  benzoic  acid. 

Gum  resins  are  natural  mixtures  of  a 
true  resin  with  another  substance  appa- 
rently of  the  nature  of  gum,  and  soluble 
in  water.  Hence,  if  they  are  triturated 
with  water,  they  remain  suspended  in  it 
in  pretty  intimate  mixture  for  a  conside- 
rable time,  forming  an  opake  emulsive  li- 
quor. By  standing,  however,  the  resin 
subsides,  and  the  liquor  becomes  clear, 
but  it  retains  the  flavour  and  smell  of  the 
gum  resin,  and  leaves,  on  evaporation,  a 
small  quantity  of  brown  extractive  mat- 
ter. Gum  ammoniac  is  an  example  of  this 
kind.  This  distinction,  however,  is  not 
very  precise,  and  is  more  useful  in  phar- 
macy than  in  pure  chemistry. 

There  are  some  substances  evidently 
resinous  in  their  nature  and  origin,  but 
which  have  other  peculiar  properties  that 
have  caused  them  to  be  excluded  from 
the  list  of  resins. 

Camphor  is  of  this  kind,  which  pos- 
sesses some  distinctive  characters  that 
have  already  been  fully  described  under 
that  article. 

Caoutchouc,  copal,  and  perhaps  amber 
also,  appear  to  belong  strictly  to  the  class 
of  resins,  but  each  has  some  points  in 
which  it  differs  materially  from  them. 

W e  shall  refer  our  readers  to  the  arti- 
cles Varsish,  and  Turpentine,  for 
I  some  of  the  most  important  individual 
resins. 

We  may  conclude  this  article  by  a 


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short  enumeration  of  the  most  important 
of  the  true  resins,  the  gum  resins,  and  the 
substances,  not  prepared  by  art,  to  which 
a  resinous  nature  has  been  usually  attri- 
buted. To  attempt  to  enumerate  them 
all  would  be  endless,  as  there  are  few 
plants  from  which  a  species  of  resin  may 
not  be  extracted  by  art,  and  even  the 
number  that  exude  spontaneously,  is 
very  great. 

Though  no  classification  will  correctly 
correspond  with  their  chemical  proper- 
ties, tlie  limits  between  the  resins  and 
gum  lesins,  not  being*  very  precise,  we 
may  usefully  arange  the  greater  part  of 
these  substances  under  the  head  of  Liquid 
Resins  or  Balsams,  Solid  Resins,  and  Gum 
Jit-sins.  The  two  first  classes  are  entirely 
or  almost  entirely  insoluble  in  water,  ex- 
cept they  contain  benzoic  acid,  but  totally 
yield  to  alcohol.  Distillation  with  water 
extracts  from  the  liquid  resins,  a  large 
quantity  of  essential  oil,  and  leaves  a  re- 
sidue much  resembling  the  solid  resins. 
The  gum  resins  are  partly  soluble  in  wa- 
ter and  partly  in  alcohol. 

Liquid  Resins. 

1.  Turpentines.  Under  this  name  we 
may  include  ail  the  liquid  resins  exuding 
from  the  different  species  of  pine,  which 
from  their  importance  in  the  arts,  and  the 
immense  consumption  of  them,  will  be  se- 
parately described  under  the  article  Tur- 
pentine. They  all  yield  abundance  of 
the  limpid  essential  oil  of  turpentine  when 
distilled,  and  by  different  modes  of  prepa- 
ration furnish  several  varieties  of  rosin, 
pitch,  tar,  &c  There  are  at  least  four 
species  of  turpentines  commonly  known 
in  the  shops,  the  Chio,  Venice,  and  Com- 
mon turpentine,  and  the  Canada  balsam. 

2.  Balsam  of  C^pivi,  or  Copaiba,  is  a 
clear  yellowish  resinous  juice,  about  the 
consistence  of  thin  treacle,  which  flows  in 
considerable  quantity  from  incisions  made 
in  the  bark  of  a  large  tree  of  South  Ame- 
rica, the  Copaifera  officinalis. 

This  balsam  has  a  very  agreeable  smell 
and  a  pungent  bitterish  taste.  It  grows 
stifier  by  long  keeping,  but  never  con- 
cretes into  a  solid.  It  dissolves  totally  in 
alcohol.  When  distilled  with  wal  er  it 
yields  nearly  half  its  weight  of  essential 
oil,  and  a  brittle  inodorous  resin  is  left.  It 
appears,  therefore,  to  be  a  natural  combi- 
nation, simply  of  resin  and  essential  oil. 

3-  Balsam  of  Mecca,  Opobalsam,  or 
Balsavi  of  Gilead.  This  is  a  liquid  resin 
which  exudes  from  the  dmyris  opobalsa- 
mum,  a  small  evergreei  tree  that  grows 
in  many  parts  of  the  Levant,  and  also  in 
great  perfection  on  the  shores  of  the  lied 
sea.    It  bears  an  extremely  high  price 


among  the  Turks,  who  employ  it  chiefly 
as  a  cosmetic,  and  it  is  scarclv  ever  found 
genuine  in  any  other  part  of  Europe. 

It  is  moderately  fluid,  of  a  yellowish 
white  colour,  very  fragrant,  and  of  a 
slightly  bitter  and  acrid  taste.  Its  che- 
mical properties  closely  resemble  those 
of  the  last  mentioned  species,  and  it  is 
only  mentioned  in  this  place  on  account 
of  the  extravagant  value  which  the  Turks 
set  upon  it,  which  is  far  beyond  that  of  all 
the  other  aromatics. 

4.  Balsam  of  Peru.  This  is  a  dark 
brown  balsam,  of  the  consistence  of  thin 
honey,  obtained  from  the  Myroxylon  Pe- 
ruiferum  (as  it  is  said)  by  boiling  the 
twigs  and  bark  in  water,  and,  when  cold, 
the  balsam  swims  at  the  top  of  the  liquor 
and  is  skimmed  off.  There  appears  to 
be  two  species  of  this  balsam,  the  white 
and  the  brown,  but  the  latter  is  the  only 
one  commonly  known. 

This  juice  has  a  very  fragrant  smell 
and  pungent  taste.  It  is  entirely  immis- 
cible  with  water  and  with  the  fixed  oils, 
but  dissolves  in  the  essential  oils,  and  in 
alcohol.  When  this  balsam  has  long  re- 
mained at  rest  in  any  vessel,  it  deposits 
crystals,  from  which  the  benzoic  acid  may 
be  obtained  by  sublimation. 

By  distillation  with  water,  this  balsam 
yields  one-sixteenth  of  its  weight  of  an  es- 
sential oil,  of  a  reddish  colour,  and  a  pun- 
gent taste.  This  oil  probably  also  con. 
tains  benzoic  acid.  When  completely 
charred  by  sulphuric  acid,  Mr.  Hatchett 
found  100  grains  to  yield  64  grains  of 
mere  charcoal.  A  compound  tincture  of 
this  balsam  forms  the  common  Friar's 
balsam,  used  as  an  application  in  cuts 
and  slight  wounds. 

5.  Balsam  if  Tolu.  This  juice  flows 
from  incisions  made  in  the  trunk  of  the 
Toluifera  balsamuvi,  a  large  tree  resem- 
bling the  pine,  which  abounds  in  the  pro- 
vince of  Tolu,  in  South  America.  It  is  of 
a  yellowish  brown  colour,  and,  when 
fresh,  of  a  thick  tenacious  consistence, 
but  by  age  it  hardens  so  as  to  be  mode- 
rately brittle  in  cold  weather. 

This  balsam  has  a  most  fragrant  smell, 
more  so  than  most  of  the  resins,  some- 
what resembling  lemons.  When  chewed 
it  clings  to  the  teeth,  and  at  first  gives 
very  little  taste,  but  after  a  time  it  leaves 
an  agreeable  pungency  in  the  mouth. 
When  kindled,  it  burns  with  a  copious 
flame  and  smoke  (like  all  the  other  re- 
sins) but  this  is  accompanied  with  a  very 
pungent  fragrant  vapour  which  excites 
coughing,  and  is  owing  to  the  volatiliza- 
tion of  the  benzoic  acid  that  this  balsam 
contains  in  soma  abundance,  though  in 
much  less  proportion  than  the  gum  ben- 


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zoin.  When  this  balsam  is  boiled  with 
water  it  melts,  and  settles  at  the  bottom 
of  the  vessel,  and  appears  to  remain  there 
unaltered,  but  the  water  without  losing- 
its  transparency  becomes  highly  fragrant 
and  pungent,  and  contains  a  notably  quan- 
tity of  benzoic  acid.  This  acid  may  also 
be  procured  from  it  by  the  same  methods 
by  which  it  is  extracted  from  the  gum 
Benzoin,  as  described  under  that  ar- 
ticle. 

Balsam  of  Tolu  is  totally  soluble  in  al- 
cohol, and  it  is  entirely  separated  from 
this  menstruum  (the  benzoic  acid  ex- 
cepted) by  water.  If  the  solution  is  not 
too  concentrated,  this  precipitated  balsam 
remains  for  a  time  suspended  in  the  li- 
quor, and  gives  it  a  miiky  appearance. 
By  distillation  this  balsam  yields  an  essen- 
tial oil  and  benzoic  acid.  A  hundred  grs. 
of  the  balsam,  charred  by  sulphuric  acid, 
gave  fifty-four  grs.  of  charcoal. 

6.  Liquidarabar,  or  Liquid  Stornx.  This 
is  a  resinous  juice,  which  flows  from  the 
trunk  of  the  Liquidambar  styracif.ua,  a 
tree  resembling  the  maple,  found  in  Vir- 
ginia and  Mexico.  This  balsam  is  of  the 
consistence  of  honey,  reddish  brown, 
nearly  transparent,  of  an  acrid,  unctuous 
taste,  and  a  fragrant  smell.  It  is  seldom 
seen,  and  has  not  been  much  examined. 

Solid  Resins. 

7.  Gum  Anime.  This  resin,  which  is 
very  rarely  met  with,  exudes  from  the 
trunk  of  the  Hymtnea  courbaril,  a  large 
tree  growing  in  Brazil  and  New  Spain.  It 
is  brought  over  either  in  small  roundish 
tears,  or  in  larger  masses,  with  the  sur- 
faces covered  with  a  white  powder.  The 
colour  is  yellowish  white  and  pellucid ;  it 
is  very  brittle,  and  gives  a  shining  frac- 
ture. It  resembles  copal  in  appearance, 
but  is  readily  distinguishable  from  it, 
(among  other  things)  by  being  easily  and 
totally  soluble  in  alcohol,  which  copal  is 
not,  without  much  difficulty  and  particu- 
lar management.  This  resin  has  very 
little  taste.  It  is  insoluble  in  water,  but 
forms  a  grateful  yellow  tincture  with  al- 
cohol, which  has  a  bitterish  pungent 
taste.  Distilled  with  water  it  gives  a  very 
small  quantity  of  essential  oil.  The  na- 
tives of  the  countries  whence  it  is  pro- 
cured chew  it,  but  it  is  never  used  in  Eu- 
rope. 

8.  Benzoin.  This  resin,  which  contains 
more  of  the  benzoic  acid  than  any  other 
substance,  has  already  been  described  un- 
der this  article. 

9,  JJragon's  Blood.  The  origin  of  this 
valuable  resin  is  not  precisely  known,  but 
it  appears  to  be  obtained  from  several 
large  trees  c  rowing  in  many  parts  of  the 


East  Indies  and  the  Indian  Archipelago, 
of  which  the  most  known  are  the  Cala- 
mus rotang,  and  I'tcrocarpus  draco.  This 
resin  is  very  largely  mixed  and  adulte- 
rated, so  that  the  samples  to  be  found  in 
the  different  slums,  often  have  scarcely 
any  other  resemblance  than  in  colour. 
The  best  sort  of  dragon's  blood  is  found 
in  irregular  roundish  pieces  about  the 
size  of  a  walnut,  often  wrapped  in  palm 
leaves,  and  of  a  deep  uniform  dull  red  co- 
lour, without  smell'or  taste.  When  bro- 
ken, its  texture  appears  homogeneous, 
but  evidently  cellular.  If  a  little  of  it  is 
rubbed  much  in  a  mortar,  the  colour 
brightens,  and  somewhat  approaches  that 
of  vermillion. 

Pure  dragon's  blood  is  entirely  insolu- 
ble in  water,  but  totally  soluble  in  alco- 
hol, forming  a  tincture  of  a  fine  blood-red 
colour.  It  burns  with  a  bright  flame,  and 
readily  consumes,  leaving  only  a  small 
portion  of  a  white  ash.  When  charred 
by  sulphuric  acid,  100  grs,  leave  48  grs. 
of  coal. 

Dragon's  blood  is  soluble  in  the  essen- 
tial oib,  and  also  in  the  fixed,  giving  them 
a  fine  red  colour.  This  resin  is  largely 
used  in  Varnishing,  (which  see)  in  lac- 
quering, and  painting,  where  a  full  bodied 
deep  red  is  wanted. 

10.  Gum  Elemi.  This  resin  comes 
over  from  South  America  in  semi-pellucid 
yellowish  masses,  generally  wrapped  up 
in  leaves,  and  visibly  contaminated  with 
bits  of  twigs  and  bark,  friable  in  the  fin- 
gers, softening  by  heat,  of  a  fragrant 
smell,  and  bitterish  taste.  The  tree  that 
yields  it  is  supposed  to  be  the  Amyris  cle- 
mifera. 

Water  dissolves  only  about  one-six- 
teenth of  this  resin,  and  the  remainder  is 
soluble  in  alcohol. 

11.  Gum  Jfedera,  is  a  resin  which  ex- 
udes in  hot  countries  from  the  stalks  and 
leaves  of  the  ivy  (Hedera  helix). 

It  appears  in  hard  compact  masses, 
reddish  brown  externally,  internally  of  a 
bright  yellow,  nearly  opake,  brittle,  and 
with  a  glossy  vitreous  fracture.  The  smell 
is  agreeable  when  rubbed,  the  taste  slight- 
ly astringent.  It  is  not  entirely  soluble 
either  in  water  or  alcohol,  so  that  in  strict- 
ness it  ought  hardly  to  be  called  a  true  re- 
sin. It  is  little  known,  and  has  not  been 
carefully  examined. 

12  Labdanum  or  Ladanum.  This  re- 
sin exudes  spontaneously  from  the  leaves 
and  branches  of  a  fragrant  shrub  (  Cistus 
C'reticus)  which  grows  abundantly  in  the 
dry  mountainous  regions  of  the  Isle  of 
Candia,  Syria,  and  other  parts  of  the  Le- 
vant. Ladanum  is  a  black,  hard,  heavy, 
resinous  mass,  rough  externally,  and  in 


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fragments,  and  its  fracture  shews  distinct  I 
sparkling  particles.  When  chewed  it 
gives  a  gritty  feel  to  the  mouth,  and  a  bit- 
terish taste,  but  does  not  dissolve.  The 
smell  is  fragant.  When  digested  with  wa- 
ter it  imparts  its  grateful  smell,  but  does 
not  sensibly  dissolve  therein.  By  distilla- 
tion it  gives  a  fragrant  essential  oil,  and  a 
tasteless  brittle  resin  remains.  Alcohol 
dissolves  all  the  resin,  and  always  shews 
in  the  undissolved  residue  a  considerable 
quantity  of  sand  and  other  impurities. 

13.  Jlastich.  This  very  valuable  resin 
is  procured  from  the  Pistacia  Lentiscus,  a 
tree  that  grows  to  ten  or  twelve  feet  high, 
and  is  cultivated  in  many  parts  of  the  Le- 
vant, particularly  in  the  island  of  Chio. 

The  best  mastich  is  in  the  form  of  small 
roundish  tears,  hard  and  brittle,  of  a  faint 
yellow  colour,  nearly  transparent,  with  a 
light  but  pleasant  smell,  and  little  or  no 
taste.  When  chewed  it  softens  in  the 
mouth,  and  excites  a  considerable  How  of 
saliva.  It  is  nearly  insoluble  in  water, 
but  gives  it  a  pleasant  flavour  when  boil- 
ed with  it.  Alcohol  and  the  essential  oils 
dissolve  mastich  entirely,  forming  a  clear 
light-yellow  tenacious  solution.,  which  ei- 
ther alone  or  with  other  resins  is  much 
employed  in  varnishing  and  other  arts. 
When  charred  by  sulphuric  acid,  100 
grains  afford  66  of  charcoal. 

14.  Sandarac.  This  resin  exsudes 
from  the  bark  of  several  kinds  of  juni- 
per, and  concretes  in  nearly  pellucid  yel- 
lowish tears  of  a  pleasant  smell,  and 
scarcely  any  taste. .  It  is  completely  solu- 
ble in  alcohol,  and  in  oils  fixed  or  essen- 
tial, and  is  much  used  in  varnishing. 

15.  To. ca7nahc.ee a.  This  resin  is  ob- 
tained from  the  Fagara  octandra,  .a  tree 
found  in  many  parts  of  South  America. 
There  are  two  sorts  of  this  resin  ;  the  best 
is  collected  in  gourd  shells,  and  is  unctu- 
ous and  soft,  of  a  greenish  yellow  colour, 
a  delightful  smell  approaching  to  that  of 
lavender,  and  a  bitterish  aromatic  taste- 
It  is  seldom  used. 

16.  Styrax,  or  Storax,  is  a  very  fragrant 
resin  procured  from  the  Styrax  officinalis, 
a  middling  sized  tree,  a  native  of  Asia. 
There  are  two  sorts  of  this  resin  ;  the 
Styrax  calamita,  composed  of  reddish 
brown  masses  of  a  waxy  consistence,  and 
free  from  visible  impurities.  The  other, 
which  is  by  much  the  commonest  sort,  is 
so  largely  adulterated  with  saw -dust,  that 
it  looks  rather  like  a  mass  of  saw-dust 
somewhat  agglutinated  by  means  of  a  soft 
clammy  resin.  Common  styrax  infused  in 
water  gives  it  a  golden  colour,  a  fragrant 
smell,  and  a  slight  balsamic  taste.  Dis- 
tillation with  water  still  further  impreg- 
nates this  liquid  with  the  same  qualities 


of  smell  arnl  taste,  and  contains  benzoic 
acid,  which  may  be  extracted  in  the  way 
mentioned  under  this  article.  When  sty- 
rax is  distilled  per  se  it  yields  along  with 
an  enip}reumatic  oil  some  crystallized 
flowers  of  benzoin.  Alcohol  dissolves 
all  the  true  styrax  from  the  impure  mass. 
In  flavour,  and,  when  pure,  in  oihei  pro- 
perties, this  resin  strongly  resembles  the 
balsam  of  Tolu. 

Gum  Resits. 

These  substances,  as  already  mention- 
ed under  this  article,  are  not  entirely  so- 
luble in  either  water  or  pure  alcohol, 
singly,  but  completely  so  in  a  mixture  of 
the  two.  Many  of  them  have  very  strong 
sensible  properties,  and  they  are  altoge- 
ther much  more  active  when  used  medi- 
cinally than  the  resins.  When  rubbed 
with  water,  they  form  a  thick  emulsion, 
from  which  most  of  the  resinous  part  se- 
parates by  repose. 

The  gum-resins  are  principally,  though 
not  entirely,  used  in  medicine. 

17.  Asafcctida.  This  gum-resin  is  the 
dried  juice  of  a  large  umbelliferous  plant, 
(Ferula  asafatida,)  which  grows  in  the 
mountains  of  Persia  and  Arabia.  It  is 
collected  by  cutting  the  mature  plant  a 
little  above  the  ground,  which  causes  a 
quantity  of  white  juice  to  exsude  on  the 
cut  surface  of  the  stock,  that  soon  con- 
cretes into  a  brownish  soft  gum.  This  is 
removed,  a  fresh  surface  is  made  on  the 
stalks  by  cutting  it  down  for  an  inch  or 
two,  and  more  of  the  juice  is  collected, 
till  after  a  time  the  whole  is  exhausted, 
and  the  stalk  dies. 

Asafoctida  is  brought  to  us  in  irregular 
masses  mostly  of  a  brownish  colour  ap- 
proaching to  red,  and  involving  smaller 
lumps  that  are  nearly  white.  It  has  a  ve- 
ry strong  fetid  smell  like  garlic,  extreme- 
ly permanent  and  diffusive,  its  taste  is 
nauseous  and  bitterish.  If  rubbed  with 
water  it  entirely  resolves  into  a  milky 
emulsion,  from  which  after  standing  for 
some  time  most  of  the  resinous  part  sub- 
sides, leaving  a  clear  supernatant  liquor 
containing  much  gum  in  solution.  Pure 
alcohol  dissolves  only  the  resinous  part, 
and  .makes  a  clear  yellow  solution.  Di- 
lute alcohol  dissolves  the  entire  resin, 
and  forms  a  brownish,  rather  turbid  tinc- 
ture. Water  distilled  off  asafcetida  rises 
strongly  impregnated  with  its  peculiar 
smell.  A  hundred  grains  charred  by  sul- 
phuric acid  yield  58  grains  of  charcoal. 

18.  Galbanum  is  the  concrete  gummy- 
resinous  juice  of  an  umbelliferous  plant 
of  Ethiopia.  (Bubon  galbanum,)  and  is 
brought  over  in  pale  semi-transparent, 
soft,  tenacious  masses,  intermixed  with 


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clear  white  tears  of  the  same  resin.  This 
juice  has  a  strong  unpleasant  smell,  and 
a  bitterish,  warm  taste.  When  rubbed 
with  water,  it  dissolves  into  a  milkv  emul- 
sion, and  has  all  other  chemical  proper- 
ties of  the  gum  resins. 

19.  Gum  Ammoniacum,  a  gum  resin 
brought  from  the  East  Indies,  composed 
of  small  white  lumps  or  tears,  more  brit- 
tle than  most  of  the  other  gum-resins, 
and  easily  reduced  to  fine  powder  in  cold 
weather.  It  unites  perfectly  with  water 
into  a  milky  emulsion,  and  water  and  al- 
cohol separately  dissolve  only  a  portion 
of  the  gum.  It  is  sometimes  employed 
in  a  small  degree  in  the  composition  of 


is  semi-transparent,  friable,  unctuous  to 
the  touch,  of  a  strong  but  not  ungrateful 
smell,  and  a  slightly  pungent  and  very 
bitter  taste.  It  burns  with  some  difficult 
ty.  It  completely  dissolves  in  boiling  wa- 
ter when  previously  pulverized,  but  on 
cooling,  a  yellow  resinous  sediment  falls 
down.  The  supernatant  liquor  evaporat- 
ed nearly  to  dryness  yields  a  saponaceous 
extract,  which  retains  much  of  the  fla- 
vour of  the  myrrh.  Alcohol  digested  with 
myrrh  forms  a  very  fine  golden  yellow 
colour,  which  is  made  turbid  by  the  addi- 
tion of  water. 

Guaiacum.    This  substance  has  usual- 


t  ry  been  reckoned  among  the  perfect  re- 
cements  and  varnishes.  A  hundred  grains  i  sins,  but  late  experiments  (though  they 
charred  by  sulphuric  acid  give  58  of  char- 1  are  not  complete)  shew  that  it  has  some 
coal.  1  very  peculiar  properties,  so  that  it  cannot 


20.  Opopanax  is  a  strong-smelling  gum- 
my resinous  juice  procured  from  the 
Pastinaca  opopanax,  and  brought  from 
Turkey  and  the  East  Indies  "in  small 
round  drops  or  irregular  lumps  of  a  red 
dish  yellow  colour.  It  mingles  perfectly 
with  water,  and  agrees  in  chemical  pro- 
perties with  the  other  gum  resins. 

21.  Sagapenum,  is  a  fetid  gum  much 
resembling  asafoctida,  but  weaker  in  sen- 
sible properties  ;  it  is  brought  from  Alex- 
andria, in  soft  irregular  masses  sticking  to 
the  fingers  when  handled.  In  chemical 
properties  it  agrees  very  closely  with  asa- 
foctida. 

22.  Olibanum.  A  gum  resin  brought 
from  Turkey  and  the  East  Indies,  in  large 
roundish  lumps,  semi-pellucid,  and  when 
of  the  purest  kind,  of  a  slight  yellow  co- 
lour. When  chewed,  it  has  a  bitterish 
pungent  taste,  and  makes  the  saliva  mil- 
ky. The  smell  is  moderately  strong,  and 
not  disagreeable.  When  laid  on  a  hot 
iron,  it  burns  with  a  strong,  penetrating, 
and  rather  fragrant  smell,  and  is  suppos- 
ed to  have  been  used  by  the  ancients  for 
incense. 

23.  Gamboge.  For  a  description  of  this 
valuable  gum,  see  the  article  Gamboge. 

24.  Euphorbium,  is  a  juice  procured 
from  a  plant  of  this  name,  brought  chiefly 
trorn  Barbary,  in  drops  of  an  irregular 
form  of  a  pale  yellow  and  brittle.  This 
gum-resin  has  but  little  smell,  but  the 
taste  is  one  of  the  most  biting  and  acrid 
of  any  known  substance,  and  the  effect  on 
+.he  organs  remains  lor  a  considerable 
time.  It  consists  of  about  equal  parts  of 
gum  and  resin. 

25.  Myrrh.  This  gum-resin  exsudes 
;Vom  a  tree  which  grows  in  Abyssinia  and 
many  parts  of  Arabia,  but  is  little  known. 
It  comes  over  in  rounded  pieces  of  various 
size,  and  still  more  varying  in  colour,  con- 
sistence, taste,  and  smell.    The  best  sort 


Je  classed  properly  either  with  the  gums 
or  resins. 

This  gum  is  procured  from  the  Guaia- 
cum iuood,  or  JJgnum  vita,  which  is  a  ve- 
ry hard,  ponderous  wood,  obviously 
abounding  with  resin,  and  as  it  were  soak- 
ed in  it,  so  that  it  has  a  peculiar  greasy 
fee),  and  a  very  strong  and  peculiar  smell 
when  rubbed. 

Gum  guaiacum  is  brought  over  in  irre- 
gular masses,  easily  friable,  of  a  dusky 
green  colour.  It  is  in  some  degree  trans- 
parent, and  it  breaks  with  a  vitreous  frac- 
ture. When  pulverized,  it  is  of  a  gray 
colour,  but  becomes  green  on  exposure  to 
air.  It  melts  when  heated,  and  gives  a  ve- 
ry pungent  aromatic  odour.  The  smell  is 
fragrant ;  it  gives  scarcely  any  taste  in 
the  mouth,  but  when  swallowed,  it  ex- 
cites a  strong  burning  sensation  in  the 
throat.  Mr.  Hatchett  has  observed  that 
guaiacum,  though  apparently  a  pure  resin, 
differs  from  all  the  pure  resins  in  giving 
much  oxalic  acid  by  the  nitric,  and  in 
yielding  scarcely  any  artificial  tannin  with 
the  nitric  acid.  Mr.  Brande  lias  since  giv- 
en an  interesting  analysis  of  this  sub- 
stance. 

When  pulverized  guaiacum  is  digested 
in  a  moderate  heat  in  distilled  water,  an 
opake  solution  is  formed,  which  becomes 
clear  on  passing  the  filter.  The  liquor  is 
of  a  greenish  brown  colour,  and  a  sweet- 
ish taste.  The  muriats  of  alumine  and 
tin,  and  nitrat  of  silver,  all  cause  a  brown 
precipitate,  and  when  the  liquor  is  evapo- 
rated an  extract  is  left.  One  hundred 
grains  of  guaiacum  yield  about  9  grains 
of  this  extract,  which  also  contains  some 
salt  of  lime,  as  shewn  by  the  oxalic  acid. 

Alcohol  dissolves  guaiacum  with  ease, 
leaving  about  5  per  cent,  of  extraneous 
matter  undissolved.  This  solution  is  of  a 
deep  brown  colour,  and  is  decomposed  by 
water,  which  separates  the  resin,  and 


SAF 


SAF 


.leaves  the  liquor  of  a  milky  hue.  If  mu- 
riatic acid  is  added  to  the  alcoholic  solu- 
tion, the  resin  at  first  separates,  which  an 
excess  of  the  acid  redis solves.  The  ad- 
dition of  nitrous  ether  to  the  tincture, 
and  subsequent  dilution  with  water, 
causes  the  resin  to  precipitate,  which 
soon  acquires  a  fine  blue  colour,  and  this 
change  of  colour  appears  characteristic 
of  the  resin  of  guaiacum,  and  has  been 
employed  as  a  means  of  detecting  any 
adulteration.  Liquid  oxymuriatic  acid 
added  to  the  tincture,  also  precipitates 
the  resin  immediately  of  the  same  blue 
colour.  Acetic  acid  causes  no  precipi- 
tate, the  resin  being  readily  soluble  in 
this  acid  Nitric  acid,  diluted  with  one 
fourth  of  its  weight  of  water,  turns  the 
tincture  green,  and  gives  a  green  precipi- 
tate after  standing  tor  some  hours,  but 
the  colour  soon  changes  to  blue,  and  af- 
terwards to  brown. 

Alkalies  do  not  cause  any  precipitation 
in  the  tincture. 

ROSIN, yellow.    See  Turpentine. 

ROTTEN-STONE.    See  Tripoli. 

ROUCOU.    See  An  not  to. 

ROUGE,  Ladies'.  See  Carmine,  and 
Colour  Making. 

ROUGE,  polishing. — This  is  a  powder 
employed  by  goldsmiths  to  give  the  last 
polish  to  their  work,  which  they  common- 
ly call  colouring  it.  The  finest  is  of  a 
high  red  colour,  and  very  soft  to  the 
touch.  It  is  said  to  be  a  very  pure  native 
red  oxide  of  iron.  Sometimes  it  is  of  a 
red  inclining  to  purple,  and  has  the  ap- 
pearance of  a  very  fine  crocus  martis : 
but  this  is  of  inferior  quality.  Chaptal 
asserts,  that  if  pieces  of  old  hat,  in  the 
dyeing  of  which  iron  is  used,  be  immersed 
a  few  minutes  in  sulphuric  acid,  the  iron 
will  pass  to  the  state  of  red  oxide,  and 
they  will  become  excellent  polishers. 

RUM — This  liquid  differs  from  simple 


sugar  spirit  in  containing  more  of  the  US 
tural  flavour,  or  essential  oil  of  the  sugar 
cane ;  a  great  deal  of  raw  juice,  and  parts 
of  the  cane  itself,  being  fermented  in  the 
liquor  of  which  it  is  prepared.  The  unc- 
tuous or  oily  flavour  of  rum  is  the  effect 
of  the  natural  flavour  of  the  sugar  cane. 

The  method  of  making  rum  is  this  :— 
When  a  sufficient  stock  of  materials  is  got 
together,  they  add  water  to  them,  and 
ferment  them  in  the  common  manner. 
When  the  wash  is  fully  fermented,  or  to  a 
due  degree  of  acidity,  the  distillation  is 
carried  on  in  the  common  way,  and  the 
spirit  is  made  up  proof;  though  some- 
times it  is  reduced  to  a  much  greater 
strength,  nearly  approaching  that  of  al- 
cohol, and  is  then  called  double  distilled 
rum.  It  would  be  easy  to  rectify  the  spi- 
rit, and  bring  it  to  a  much  greater  purity 
than  we  usually  find  it  to  be ;  for  it  brings 
over  in  the  distillation  a  very  large  quanti- 
ty of  the  oil,  and  this  is  often  so  disagree- 
able, that  the  rum  must  be  suffered  to  lie 
by  a  long  time  to  mellow,  before  it  can  be 
used  ;  whereas,  if  well  rectified,  it  would 
grow  mellow  much  sooner,  and  would 
have  a  much  less  potent  flavour.  If  the 
business  of  rectifying  was  more  nicely 
managed,  it  seems  very  practicable  to 
throw  cut  so  much  of  the  oil  as  to  have 
it  in  the  fine  light  state  of  a  clear  spirit. 
In  this  state  it  would  very  near  resemble 
arrac,  as  is  proved,  by  mixing  a  very  small 
quantity  of  it  with  a  tasteless  spirit. 

Rum  is  usually  very  much  adulterated. 
Some  do  it  with  malt  spirit ;  but  if  done 
with  molasses  spirit,  the  tastes  of  both  are 
so  nearly  allied,  that  it  is  not  easily  disco- 
vered. See  Arrack,  Alcohol,  Bran- 
dy, Distillation  of  Spirits,  &c. 

RUST.— Oxydized  iron  is  commonly  so 
called.    See  Iron. 

RYE.    See  Agriculture. 


s. 


SAFFLOWER.  Carthamus,  or  lias, 
tard  Saffron. 

This  plant,  the  flower  of  which  is  em- 
ployed in  dyeing  and  colouring,  is  culti- 
vated in  Spain,  and  in  many  parts  of 
the  Levant,  from  which  it  is  chiefly  im- 
ported. 

This  dyeing  material,  contains  two  co- 
louring matters,  a  yellow  and  red,  the 
former  of  these  alone,  is  soluble  in  water, 
and  is  comparatively  of  little  value,  the 
latter  is  soluble  in  alkalies,  and  precipi- 


tated thence  by  several  acids  and  forms, 
a  beautiful  rose-red  pigment.  This  is 
partly  used  for  silk  dyeing,  but  the  great 
consumption  of  it  is  in  the  rouge,  so  cele- 
brated as  a  cosmetic,  and  of  which  it 
forms  the  essential  ingredient. 

To  prepare  the  carthamus  for  this  pur- 
pose, it  is  necessary  first  to  extract  the 
yellow  portion,  which  is  done  by  tying  the 
plant  in  a  linen  bag,  and  then  washing  it 
incessantly  with  water,  using  much 
squeezing  and  rincing,  till  the  water  pass- 


SAG 


SAL 


es  off  colourless.  The  residue  in  the  linen 
bag,  now  consists  of  the  fibrous  part  of 
the  plant,  and  of  the  valued  red  fecula, 
which  last  however,  is  in  very  small  quan- 
tity. This  is  extracted  by  digesting'  the 
washed  carthamus,  in  a  solution  of  carbo- 
nat  of  soda,  (without  applying  artificial 
heat,  which  would  impair  the  colour,) 
and  this  gives  an  orange  yellow  alkaline 
solution,  which  on  saturation  with  acids 
turns  red,  and  gradually  deposits  a  beau- 
tiful red  fecula,  which  is  the  pigment  in 
question.  Lemon  juice  is  the  acid  pre- 
ferred. But  as  the  colour  of  this  red  fe- 
cula is  extremely  intense,  it  will  bear  di- 
lutions, which  is  done  chiefly  by  rubbing1 
it  with  finely  powdered  talc,  in  different 
proportions. 

Alcohol  will  also  dissolve  the  red  part 
of  carthamus  ;  and  alter  the  yellow  por- 
tion has  been  extracted  by  water,  a  fine 
red  tincture  is  made  by  digesting  the  re- 
sidue in  alcohol. 

On  account  of  the  high  price  of  cartha- 
mus, it  is  seldom,  if  ever  employed,  ex- 
cept for  giving  a  finishing  gloss  to  dyed 
silks,  and  for  the  preparation  of  rouge. 
Alkalies  of  every  kind,  immediately  alter 
the  colour,  to  an  orange  yellow,  again  re- 
storable  by  acids.    See  Dyeing. 

SAFFE.    See  Zaffe. 

SAGO.  The  Sago-tree,  cycas  circina- 
lis,  grows  spontaneously  in  the  East  in- 
dies, and  particularly  in  the  Moluccas,and 
on  the  coast  of  Malabar. 

This  is  a  valuable  tree  to  the  inhabi- 
tants of  India,  as  it  not  only  furnishes  a 
considerable  part  of  their  constant  bread, 
but  also  supplies  them,  with  a  large  ar- 
ticle of  trade.  It  runs  up  with  a  straight 
trunk,  to  forty  feet  or  more.  The  body 
contains  a  farinaceous  substance,  which 
they  extract  from  it,  and  make  into 
bread. 

The  tree,  which  seems  to  grow  merely 
for  the  use  of  man,*points  out  the  meal 
by  a  fine  white  powder,  which  covers  its 
leaves,  and  is  a  certain  indication,  of  the 
maturity  of  the  Sago.  The  inhabitants 
then  cut  it  down  to  the  root,  saw  the  bo- 
dy into  small  pieces,  and  after  beating 
them  in  a  mortar,  pour  water  upon  the 
mass  ;  this  is  left  for  some  hours  to  settle. 
When  fit,  it  is  strained  through  a  cloth, 
and  the  finer  particles  of  the  mealy  sub- 
stance, running  through  with  the  water, 
the  gross  ones  are  left  behind  and  thrown 
away.  After  the  fecula  is  sufficiently 
subsided,  the  water  is  poured  off,  and  the 
meal  being  properly  dried,  is  occasionally 
made  into  cakes,  and  baked.  These 
cakes,  are  said  to  eat  nearly  as  well,  as 
wheaten  bread,  and  are  the  support  of 


the  inhabitants,  for  three  or  four  months 
in  the  year. 

The  fecula  being  passed  through  per- 
forated copper-plates,  is  formed  into  the 
grains  called  Sago.  It  forms  an  agreea- 
ble jelly,  with  water,  milk,  or  broth,  and 
is  much  used  in  phthisical  and  convales- 
cent cases. 

There  is  a  sort  of  Sago  brought  from 
the  West  Indies,  but  far  inferior  in  quality 
to  that  coming  from  the  East  It  is  sup- 
posed to  be  made  from  the  pith,  or  areca 
oleracea. 

SAL  AMMONIAC.  Muriat  of  Jim 
monia.    Salzaurts  ammortiak.  Germ. 

This  neutral  salt,  consisting  of  muria- 
tic acid  and  ammonia,  in  a  state  of  mutual 
saturation,  was  not  unknown  to  the  anci- 
ents. In  the  time  of  Pliny,  it  was  import- 
ed into  Europe  from  Egypt,  and  continued 
to  be  furnished  by  the  same  country,  to 
the  various  states  of  modern  Europe,  till 
within  the  last  fifty  or  sixty  years.  It  has 
also  been  prepared  in  India  (probably  in 
the  same  manner  as  in  Egypt)  from  time 
immemorial.  Before  treating  of  the  pro- 
perties of  this  salt,  we  shall  give  an  ac- 
count of  its  manufacture,  first  in  Egypt, 
and  then  in  the  various  countries  of  Eu- 
rope. 

On  account  of  the  great  want  of  wood 
in  Egypt,  the  principal  fuel  of  the  country 
is  composed  of  the  dung  of  camels,  cows, 
and  other  domestic  gramnivorus  quadru- 
peds, mixed  up  with  chopped  straw,  and 
dried  in  the  sun.  The  soot  produced  by 
the  combustion  of  this  fuel,  is  the  mate- 
rial from  which  sal  ammoniac  is  prepared, 
by  sublimation.  The  vessels  made  use  of 
on  this  occasion,  are  very  thin  globular 
glass  baloons,  with  a  short  neck  terminat- 
ing in  a  mouth  about  H  inch  in  diameter. 
The  largest  balloons  are  about  36  inches 
across,  but  they  are  of  various  sizes,  being 
capable  of  containing  when  three-quarters 
full,  from  12  to  50  lbs.  of  soot.  In  order 
to  secure  them  as  much  as  possible  from 
breaking,  during  the  process,  they  are 
coated  with  a  mixture  of  mud,  deposited 
by  the  Nile,  and  chopped  straw. 

It  has  been  affirmed  by  the  Jesuit  le 
Pere  Sicard,  and  some  others,  that  the 
soot  is  mixed  with  a  certain  proportion  of 
common  salt,  and  camels'  urine,  but  this 
appears  to  be  a  mistake  ;  being  absolute- 
ly contradicted  by  the  most  accurate  en- 
quirers. From  these  it  appears,  that  no 
other  ingredient  is  made  use  of,  but  soot, 
with  which,  moderately  pressed  down, 
the  balloons  are  filled,  to  within  about 
four  finger's  breadth  of  the  neck.  The 
vessels  thus  charged  are  arranged,  to  the 
number  of  60  or  70,  in  an  oblong  furnace 


SAL 


SAL 


of  brick,  and  secured  with  clay,  so  that 
the  necks  alone  are  in  contact  with  the 
external  air.  The  furnace  is  now  very 
gradually  heated,  by  means  of  straw,  for 
the  first  three  or  four  hours,  and  after- 
wards, with  a  mixture  of  straw  and  the 
common  fuel  of  the  country,  viz.  dried 
dung-.  In  the  course  of  six  or  seven  hours, 
a  thick  somewhat  acid  empyreumatic 
smoke,  begins  to  rise  out  of  the  balloons, 
and  continues  for  about  fifteen  hours. — 
The  sublimation  of  the  sal  ammoniac  com- 
mences  three  or  four  hours,  before  the 
smoke  ceases,  and  continues  from  15  to 
40  hours,  according-  to  the  size  of  the  bal- 
loon, without  any  further  care  being-  re- 
quired, than  to  regulate  the  fire  properly, 
and  to  pass  an  iron  rod  occasionally  down 
the  necks  of  the  balloons,  to  prevent  them 
from  being  clogged  up  by  the  salt,  as  it 
rises,  and  thus  producing  an  explosion. 
When  the  sublimation  ceases,  the  fire  is 
allowed  to  go  out,  and  the  vessels  as  soon 
as  they  are  sufficiently  cool,  are  removed 
from  the  furnace  and  broken  ;  the  cake 
of  sal  ammoniac,  which  occupies  their 
upper  part,  is  in  the  form  of  a  very  shal- 
low bason,  and  weighs  on  an  average 
somewhat  more  than  one-seventh  of  the 
soot  employed  ;  it  has  generally  a  yellow- 
ish white  tinge,  and  is  apt  to  be  fouled 
with  a  little  charcoal,  especially  if  the  heat 
has  been  too  great. 

The  proportion  of  salt,  from  a  given 
quantity  of  soot,  is  liable  however  to  con- 
siderable variation  :  it  is  found  that  the 
dung"  of  the  same  animal,  affords  a  soot 
much  richer  in  salt,  when  it  is  fed  on  fresh 
vegetables,  than  on  hay  and  other  dry 
food.  There  is  besides  a  great  difference 
in  the  soot,  from  the  dung  of  different 
animals,  similarly  circumstanced  as  to 
food.  According  to  Mr.  Granger,  the 
Egyptian  sal  ammoniac  makers,  esteem 
the  soot  of  cow-dung,  when  the  animal  is 
fed  on  grass,  to  be  by  far  the  best,  26  lbs. 
affording  no  less  than  6  lbs.  of  salt.  Ac- 
cording to  Hasselquist,  however,  the  soot 
from  the  dung  of  goats  and  sheep,  is  in 
the  highest  estimation. 

In  this  very  simple  manufacture,  the 
sal  ammoniac  appears  to  exist  ready 
formed  in  the  soot,  and  the  action  of  the 
heat,  is  confined  to  the  mere  separation 
of  the  saline,  from  the  other  ingredients. 
The  soot  itself  is  of  a  deep  black  colour, 
has  very  sensibly  the  taste  of  sal  ammo- 
niac, and  when  strongly  heated,  gives  out 
a  sulphureous  odour. 

In  Europe,  where  dung  is  employed  to 
no  better  purposes  than  for  fuel,  the  ma- 
nufacture of  sal  ammoniac,  is  a  much  more 
complicated  process,  especially  when 
carried  on  in  the  best  and  most  econo- 

VOL.  II. 


mical  manner.  A  kind  of  intermediate 
method  however,  is  practised  with  suc- 
cess, in  some  establishments  in  the  Ne- 
therlands, of  which  the  following  are  tlie 
principal  details. 

A  kind  of  fuel  capable  of  furnishing  sal 
ammoniac  by  its  combustion,  is  first  pre- 
pared, the  ingredients  of  which  are, 

Twenty-five  parts  by  measure,  of  pul- 
verized pit  coal. 

Five  parts  by  measure,  of  common 
chimney  soot. 

Two  parts  by  measure,  of  clay. 

To  these  is  added,  a  saturated  solution 
of  common  salt,  in  sufficient  quantity  to 
bring  the  whole  to  a  consistence,  for  being 
moulded  into  balls.  The  balls  are  of  an 
oval  form,  and  after  being  dried  in  the 
air,  are  ready  for  use. 

The  apparatus  for  collecting  the  soot, 
produced  by  the  combustion  of  the  fuel, 
consists  of  a  brick  furnace,  communicat- 
ing by  a  flue,  two  inches  in  diameter,with 
a  vaulted  chamber,  also  of  brick,  from  the 
opposite  extremity  of  which,  there  passes 
out  a  flue  of  the  same  diameter,  as  that 
already  mentioned,  terminating  in  a  hori- 
zontal gallery,  at  the  end  of  which  is  the 
chimney.  The  furnace  is  charged  with 
the  balls  above  mentioned,  to  which  is 
added,  a  somewhat  variable  proportion  of 
dry  bones  ;  and  with  these  materials  an 
incessant  fire  is  kept  up,  for  from  four  to 
six  months.  At  the  expiration  of  this  time, 
the  vaulted  chimney  and  gallery  are  open- 
ed, and  the  soot  with  which  they  are  lined 
is  scraped  off,  from  the  top,  the  sides,  and 
floor,  observing  to  keep  the  soot  from  the 
latter,  distinct  from  the  rest. 

The  principal  new  combinations,  that 
take  place  in  consequence  of  the  combus- 
tion, appear  to  be  the  following :  first,  the 
pit-coal  is  resolved  into  gas  of  various 
kinds,  into  empyreumatic  oil,  loaded  with 
finely  divided  charcoal,  and  into  carbo- 
nated ammonia  :  the  soot  forms  carbonic 
acid,  and  also  gives  out  the  carbonated 
ammonia  which  it  contained :  the  bones 
afford  empyreumatic  animal  oil,  and  car- 
bonated ammonia  ;  and  the  common  salt 
by  the  action  of  the  clay,  is  decomposed, 
its  alkaline  base  remaining  united  to  the 
earth,  and  its  acid  passing  in  a  gasseous 
state  into  the  chamber,  where  it  meets 
with  and  decomposes  the  carbonated  am- 
monia, forming  sal  ammoniac.  Hence  the 
contents  of  the  soot  collected  in  the  cham- 
ber, are  carbonaceous  matter,  muriat  of 
ammonia,  and  empyreumatic  bituminous 
oil :  the  latter  of  which  is  particularly 
abundant,  in  the  soot  that  concretes  on 
the  floor. 

To  separate  the  sal  ammoniac  from 
the  other  ingredients,  sublimation  is  had 
V  U 


SAL 


SAL 


recourse  to,  and  is  thus  performed.  Se- 
veral egg-shaped  jars,  made  of  earthen- 
ware, about  20  inches  high,  and  16  in 
diameter,  with  a  mouth  2h  inches  wide, 
are  fixed  in  a  furnace,  and  as  soon  as  they 
are  become  moderately  warm,  are  charg- 
ed with  soot,  broken  into  small  pieces,  to 
within  three  inches  of  their  mouths  ;  a 
duly  regulated  heat  is  then  kept  up  for 
48  hours,  in  which  time  the  volatile  oil 
first  rises,  and  passes  out  into  the  air,  then 
the  sal  ammoniac  sublimes,  and  fixes  it- 
self to  the  upper  part  of  the  jars,  while 
the  earthy  and  carbonaceous  impurities 
remain  at  "the  bottom  ;  the  vessels  are  then 
broken,  and  the  cakes  of  salt  extracted. 
Fifteen  pounds  of  soot  afford  on  an  ave- 
rage, about  five  pounds  of  muriated  am- 
monia. The  soot  from  the  floor  of  the 
chamber,  is  too  much  loaded  with  bitu- 
men, to  admit  of  die  salt  being  extracted 
from  it,  by  simple  sublimation,  and  the 
most  economical  way  of  treating  it,  is  to 
burn  it  over  again,  by  which  the  bitumen 
is  destroyed,  and  the  sal  ammoniac  mix- 
ed with  the  soot,  rises  uninjured  into  the 
chamber. 

The  method  of  carrying  on  the  manu- 
facture of  this  salt  in  England,  though 
more  complicated  than  the  above,  is,  we 
apprehend,  considerably  more  economi- 
cal. The  following  was  the  actual  prac- 
tice, at  a  large  establishment  near  Lon- 
don, which  was  abandoned  a  few  years 
ago,  in  consequence  of  Glauber's  salt 
being  subjected  to  the  excise. 

The  material  from  which  the  ammonia 
was  extracted  was  bones.  These  were 
collected  in  the  streets  and  from  dung- 
hills, chiefly  by  old  women.  The  bones 
having  been"  thus  procured,  were  chopped 
into  small  pieces  either  by  hatchets  or  ma- 
chinery, and  then  boiled,  in  order  to  ex- 
tract the  grease  or  fat  and  marrow  re- 
maining in  them,  which  was  sold  to  the 
soap-boilers.  The  bones  were  then  thrown 
into  a  cylindrical  iron  still,  about  3  feet  in 
diameter,  and  8  or  9  feet  long,  laid  hori- 
zontally over  a  fire-place,  so  as  to  be  ca- 
pable of  being  made  moderately  red-hot. 
At  one  end  of  the  cylinder  was  a  mouth 
about  14  inches  in  diameter,  by  which  the 
bones  were  introduced,  and  furnished 
with  a  cover  capable  of  closing  it  accu- 
rately by  the  help  of  a  little  lute  From 
the  other  end  of  the  cylinder  proceeded 
a  cast  iron  pipe,  from  6  to  8  inches  in  dia- 
meter, and  18  or  20  feet  long,  terminat- 
ing in  one  or  more  oblong  leaden  receiv- 
ers, which  were  kept  cool  by  water, 
placed  in  a  vessel  of  the  same  materials, 
the  bottom  of  which  formed  their  cover, 
the  juncture  being  secured  by  lute.  Of 
these  receivers  there  were  commonly  two 


to  each  still,  or  three  to  two  stills.  Every 
receiver  was  about  12  feet  long,  1  foot 
deep,  and  14  inches  wide,  and  the  refri- 
geratory which  covered  it  held  about  4 
inches  in  depth  of  water :  at  the  end  the 
most  remote  from  the  still  was  a  pipe,  fit- 
ted with  a  wooden  plug  for  the  purpose 
of  drawing  off"  the  condensed  liquor,  and 
above  this  was  a  hole  through  which  the 
gas  and  incondensible  vapour  passed  off 
into  the  open  air. 

A  single  charge  of  each  still  yielded 
about  36  lbs.  of  impure  alkaline  liquor, 
and  about  30  lbs.  of  black  fetid  oil  float- 
ing upon  its  surface.  This  latter  being 
skimmed  off,  the  alkali  was  saturated 
with  sulphuric  acid,  either  by  the  addi- 
tion of  the  mother  liquor  from  the  green 
vitriol  makers  (consisting  for  the  most 
part  of  red  sulphat  of  iron)  ;  or  still  more 
economically  by  means  of  calcined  and 
pulverized  gypsum  :  in  this  latter  case, 
after  mixing  the  materials,  and  stirring 
them  well  together,  they  are  to  be  left  at 
rest  for  some  hours,  during  which  a  dou- 
ble decomposition  takes  place,  the  sulphat 
of  lime  yielding  part  of  its  acid  to  the 
ammonia,  and  at  the  same  time  depriving 
this  latter  of  its  carbonic  acid.  The  solu- 
tion of  sulphat  of  ammonia  thus  produc- 
ed is  then  mixed  with  common  salt,  by 
which  another  decomposition  takes  place, 
the  alkali  of  the  former  and  the  acid  of 
the  latter  uniting  to  form  muriat  of  ammo- 
nia, while  the  two  remaining  ingredients 
produce  by  their  combination  sulphat  of 
soda. 

The  liquor  containing  these  two  sails  is 
then  clarified  by  subsidence  and  decanta- 
tion,  and  transferred  into  oblong  leaden 
boilers,  about  9  feet  long,  3  wide,  and  9 
inches  deep.  The  boilers  are  set  for 
about  two  thirds  of  their  length  on  iron 
plates,  heated  by  a  fire  beneath,  the  re- 
maining part  being  supported  by  flat  tiles 
defended  by  solid  brick-work  from  the 
access  of  the  heat.  As  the  water  evapo- 
rates the  Glauber  salt  begins  to  crystal- 
lize, and  is  swept  from  time  to  time  to 
the  cool  extremity  of  the  boiler,  whence 
it  is  shovelled  out  into  baskets  arranged 
over  the  end  of  the  boiler,  that  the  liquor 
which  drains  from  the  small  granular  crys- 
tals may  not  be  lost.  The  evaporation  is 
continued  for  several  hours,  till  as  much 
as  possible  of  the  Glauber's  salt  has  been 
separated,  and  the  muriat  of  ammonia  be- 
gins to  crystallize  on  the  surface  of  the 
liquor  in  the  form  of  feathered  stars.  The 
remaining  liquor  is  then  run  off  into  cool- 
ers, and  deposits  little  else  than  muriat  of 
ammonia,  till  it  gets  below  the  tempera- 
ture of  70°  Fahr.  at  which  time  the  crys 
tals  are  to  be  removed,  lest  they  should 


SAL 


SAL 


be  mixed  with  Glauber's  salt,  which  now 
begins  to  be  again  deposited.  After  the 
muriat  of  ammonia  has  been  suffered  to 
drain  in  the  baskets,  it  is  removed  to  a 
kind  of  oven,  or  even  an  open  tiled  hearth 
heated  from  below,  where  the  water  of 
crystallization  is  driven  off,  by  which  the 
salt  becomes  spongy,  friable,  and  of  an 
ash  or  slate  colour,  interspersed  with 
small  white  filaments. 

The  salt  is  now  removed  while  hot  in- 
to globular  glass  receivers,  or  more  com- 
monly glazed  earthen  jars,  fitted  with  a 
cover  (having  a  hole  of  above  half  an  inch 
diameter  in  its  centre)  luted  on  with  a 
mixture  of  clay  and  horse-dung  These 
are  set  in  iron  pots  over  a  strong  fire,  in 
a  furnace  of  either  a  circular  or  oval  form, 
and  capable  of  containing  from  six  to 
eighteen,  surrounded  with  sand  up  to  the 
edge  of  the  pot,  and  also  having  about 
two  and  a  half  inches  of  sand  on  the  co- 
ver, confined  by  an  iron  ring  about  three 
inches  deep,  and  two  inches  less  in  diame- 
ter than  the  cover,  in  order  thai  if  the 
luting  should  give  way  in  any  part,  it  may 
be  repaired  without  suffering  the  covers 
(which  should  be  kept  during  the  subli- 
mation at  about  320°)  to  be  cooled  by  the 
removal  of  a  large  portion  of  the  sand 
These  earthen  pans  maybe  filled  to  with- 
in two  inches  of  the  top,  with  the  dried 
salt  gently  pressed  in,  but  not  rammed 
close;  and  the  fire,  which  has  been  light- 
ed some  time  before,  is  now  to  be  raised 
gradually  till  the  iron  pots  are  of  a  pretty 
strong  red  heat  all  round,  being  so  placed 
in  the  furnace  that  the  upper  part  may  be 
first  heated,  the  bottom  resting  on  solid 
brick-work.  During  the  first  impression 
of  the  heat,  a  portion  of  the  salt  carrying 
with  it  a  quantity  of  watery  vapour  not  se- 
parated on  the  drying  place,  will  escape 
through  the  hole  in  the  cover,  which  must 
be  left  open  till  all  the  aqueous  particles 
are  exhaled  :  this  is  known  by  bringing  a 
piece  of  rol'd  smooth  iron  plate  near  the 
hole  in  order  to  condense  the  sublimate, 
which,  becoming  more  and  more  dry,  at 
length  attaches  itself  firmly  to  the  plate, 
in  the  form  of  a  dry  semi-transparent 
crust.  At  this  time  the  hole  is  to  be  stop- 
ped with  a  bit  of  lute,  more  sand  is  to  be 
put  on  the  cover,  and  the  heat  continued 
till  it  is  judged  that  nearly  the  whole  of 
the  muriat  of  ammonia  is  sublimed.  The 
time  requisite  for  this  purpose  depends  on 
the  structure  of  the  furnace,  the  size  of 
the  pots,  the  briskness  of  the  fire,  and 
other  circumstances  only  to  be  learnt  by 
experience.  The  process  should  be  stop- 
ped before  the  sublimation  has  entirely 
ceased,  as  the  heat  in  some  parts  of  the 


jar  may  be  too  great  when  it  is  nearly 
empty,  and  either  by  burning  a  part  of 
the  salt  itself,  or  elevating  a  portion  of  fo- 
reign matter  from  which  it  can  never  be 
kept  wholly  free,  give  the  cake  a  yellow 
tinge,  and  a  scorched,  opake,  crackled, 
appearance.  The  same  defects  are  likely 
to  happen,  when  any  part  of  the  luting 
having  given  way,  is  obliged  to  be  repair- 
ed by  wet  lute,  when  the  sublimation  is 
pretty  far  advanced :  consequently  glass 
vessels  are  preferable,  except  on  account 
of  the  expense,  as  they  must  always  be 
broken  to  pieces  in  order  to  get  out  the 
cake :  the  jars  on  the  contrary  will  serve 
for  several  sublimations,  even  the  covers, 
if  well  glazed,  will  last  for  two  opera- 
tions. The  sublimation  being  finished, 
and  the  apparatus  having  become  suffi- 
ciently cool,  the  tops  of  the  jars  are  to 
be  taken  off,  and  the  cakes  of  sal-ammo- 
niac that  are  found  adhering  to  them  are 
to  be  separated,  and  placed  for  a  day  or 
two  in  a  damp  atmosphere,  which  softens 
their  surface  a  little,  and  thus  facilitates 
the  removal  of  any  superficial  impurities. 
Lastly,  the  cakes  are  packed  up  in  casks 
for  sale- 

The  following  is  a  table  of  the  propor- 
tions of  dry  carbonat  of  ammonia  afford- 
ed by  different  substances : 

Horn    -    -    -    1 -fifth, 
Feathers  -    -  2-elevenths, 
Wool   -    -    -    1 -eighth, 
Soot     -    -    -  1-fifteenth, 
Bones  -    -    -  1-sixteenth, 
Blood  -    -    -  1-seventeenth, 
Putrid  urine  -  1-forty-sixth. 
In  common  manufactories  the  dry  car- 
bonat yields  rather  less  thanitwo-thirds  of 
sal-ammoniac    In  most  of  the  Scotch 
manufactories  soot  is   used  instead  of 
bones,  these  latter  being  only  to  be  pro- 
cured abundantly  in  the  vicinity  of  a  ve- 
ry large  town. 

The  water  of  composition  contained  in 
sal-ammoniac  is  the  same  in  quantity  ac- 
cording to  Beaume,  whether  the  salt  is 
sublimed,  or  crystallized  from  its  aque- 
ous solution.  With  this  Mr.  Kir  wan 
agrees,  who  states  the  component  parts 
of  sal-ammoniac,  whether  sublimed  or 
crystallized,  at 

42.75  Muriatic  acid 
25.  Ammonia 
32.25  Water 


100.00 


The  uses  of  sal-ammoniac  are  conside- 
rable. Beside  being  employed  in  the  la- 
boratory as  the  substance  from  which 
pure  and  carbonated  ammonia  are  pro^ 


SAL 


SAL 


cured,  it  is  used  in  substance  by  the  dy- 
er, the  refiner  of  gold,  the  copper-smith, 
and  the  manufacturer  of  tin-plate. 

SAL  GEM,  is  rock  salt. 

SAL  MAUTIS,  is  the  green  sulphat  of 
iron.    See  Iron 

SAL  POLYCHREST,  is  Sulphat  of 
Potash,  calcined  with  a  very  small  por- 
tion of  sulphur,  formerly  used  in  medi- 
cine. 

SAL  PRUNELLA,  is  Nitr*t  of  Pot- 
ash,  from  which  the  water  of  crystalliza- 
tion has  been  expelled  by  fusion. 

SALEP.  The  powder  of  the  orchis 

root.  The  farina  of  potatoes  is  said  to  be 
an  excellent  substitute  for  salep,  and  less 
liable  to  spoil  by  keeping 

SALT — This  term  has  been  so  various* 
lv  applied,  that  it  is  scarcely  possible  to 
give  an  accurate  definition  of  it.  The  ge- 
neral and  the  most  antient  idea  of  a  salt 
is,  a  crystallizable  substance,  considera- 
bly soluble  in  water,  and  highly  sapid  ; 
but  the  term  is  at  present  applied  to  all 
the  crystallizable  acids  or  alkalies,  or 
earths,  or  combinations  of  acids  with  al- 
kalies, earths,  or  metallic  oxyds.  Hence 
the  common  and  useful  distinction  of  the 
compounded  salts  into  alkaline,  earthy, 
and  metallic.  In  so  doing,  however,  and 
by  including  all  the  crystallizable  combi- 
nations of  acids  and  bases,  some  com- 
pounds have  got  the  name  of  salts  which 
want  the  primary,  (and  what  would  for- 
merly have  been  considered  as  essential,) 
qualities  of  solubility  and  sapidity,  of 
which  sulphat  of  barytes  is  an  example, 
which  is  absolutely  insoluble  in  water  and 
tasteless.  It  is  still,  however,  crystalliza- 
ble, or  found  crystallized,  which  appears 
to  be  an  invariable  character  of  a  salt. 
Thus  this  appellation  was  long  denied  to 
carbonat  of  magnesia,  till  the  discovery 
of  the  crystallizable  soluble  carbonat  of 
this  earth. 

There  are  many  triple  combinations  al- 
so of  these  ingredients,  which  belong  to 
the  class  of  salts,  such  as  alum,  tartariz- 
ed  antimony,  &x. 

Salts  are  also  either  neutral  (that  is, 
where  the  ingredients  are  in  exact  satura- 
tion) or  with  the  acid  in  excess,  of  which 
tar  is  an  example,  or  with  an  excess  of 
the  base,  as  in  borax.  These  circum- 
stances have  been  ingeniously  distinguish- 
ed in  nomenclature  by  Dr.  Thomson,  by 
the  prefix  super  in  the  first  case,  and  sub 
in  the  latter.  Thus  tartar  is  named  with 
propriety  the  super-tartrite  of  potash  ;  bo- 
rax, the  sub  borat  of  soda,  &c. 

The  term  salt  is  also  used  emphatical- 
ly for  common  salt,  or  muriat  of  soda. 

SALT,  Bitter,  Purging,  or  Epsom.  See 
Epsom  Salt. 


SALT,  Glauber's.     See  Glauber's 

Salt. 

SALT,  Spirit  of.  See  Muriatic 
Actd. 

SALTPETRE.    See  Nitre. 

SALT,  Common  Salt,  Muriat  of  Soda.-~ 
This  salt  exists  abundantly  native  either 
as  a  solid  fossil  or  dissolved  in  water.  In 
the  former  case  it  ranks  as  a  peculiar  mi- 
neral species,  and  will  be  described  ac- 
cordingly. 

ROCK  SALT,  or  Fossil  Salt,  or  Sal 
Gem. — Of  this  species  there  arc  the  two 
following  varieties. 

Var.  1.  Foliated  rock  salt. 

Var.  2.  Fibrous  rock  salt. 

Rock  salt  forms  a  peculiar  species  of 
rock,  the  proper  geological  situation  of 
which  is  between  the  oldest  secondary 
gypsum  and  secondary  sandstone  :  it 
forms  continuous  beds  of  great  thickness, 
and  often  occurs  in  large  solitary  blocks  : 
it  is  always  accompanied  by  semi-indurat- 
ed clay,  for  the  most  part  strongly  im- 
pregnated with  salt;  and  alternates' with 
beds  of  swinestone,  gypsum,  limestone, 
and  sandstone.  The  beds  of  salt  are  most- 
ly below  the  surface  of  the  ground,  but 
sometimes  it  rises  into  hills  of  considera- 
ble elevation.  At  Cordova,  in  Spain,  ac- 
cording to  Bowles,  there  is  a  hill  between 
four  and  five  hundred  teet  high,  compos- 
ed entirely  of  this  mineral. 

To  begin  with  Europe  :  there  are  in 
Spain  a  considerable  number  of  brine- 
springs,  and  some  mines  of  sal  gem.  Se- 
veral of  these  are  in  lofty  situations.  Mr. 
Bowles,  who  makes  this  observation,  re- 
marks too,  tli at  all  the  salt-springs  issue 
from  the  foot  of  some  mountain.  Such  are 
those  of  the  Pyrenees. 

The  mine  of  Cardonna,  in  Catalonia, 
near  the  mountain  of  Montserrat,  is  re- 
markable for  this,  that  the  salt  forms  a 
homogeneal  mass,  without  any  appear- 
ance of  stratum  or  crevice,  raised  about 
a  hundred  and  eighty  yards  above  the 
earth,  and  extending  about  three  miles  in 
circumference.  Neither  the  depth  of  this 
heap  of  salt,  nor  the  nature  of  the  ground 
on  which  it  rests,  is  known.  The  salt  com- 
posing it  is  whitej  or  red,  or  light  blue, 
and  is  not  accompanied  with  sulphat  of 
lime,  which  is  a  rare  occurrence. 

The  mine  of  Valtierra,  in  the  kingdom 
of  Navarre,  near  the  Ebro,  is  in  a  chain 
of  hills  at  a  considerable  elevation  above 
the  level  of  the  sea.  It  is  enclosed  in 
sulphat  of  lime. 

Beside  these,  the  mine  of  Servato,  in 
the  Pyrenees,  is  mentioned ;  and  the 
spring  of  Salinas,  between  Vittoria  and 
Mondragon,  in  the  most  elevated  part  of 
Guipuscoa. 


SAL 


SAL 


In  La  Mancha,  at  Almengranilla,  there 
is  a  mass  of  salt  similar  to  that  of  Cai  don- 
na. It  is  seventy  yards  in  diameter,  mix- 
ed with  suiphat  of  lime,  and  covered  with 
the  same  stone,  including  crystals  of  red 
quartz ;  above  which  are  siliceous  pud- 
dingstones,  and  a  stuatum  of  carbonat  of 
lime. 

The  mines  of  sal  gem,  that  are  wrought 
at  Poza,  near  Burgos,  in  Castille,  have  a 
remarkable  situation,  being  placed  in  a 
vast  crater.  Mr.  Fernandez  has  found 
pumice-stones,  puzzolana,  and  other  vol- 
canic productions  there. 

Sal  gem  is  likewise  found  near  Aran- 
juez,  and  Ocanna,  in  the  transition  hills  be- 
tween Sierra-Morena  and  Madrid. 

No  mine  of  sal  gem  has  hitherto  been 
found  in  France^  but  there  are  a  tolerable 
number  of  brine- springs,  of  which  we  shall 
mention  those  of 

Sallies,  at  the  foot  of  the  Pyrenees, 
near  Orther,  in  the  department  of  the 
Lower  Pyrenees.  The  soil  is  calcareous. 
Suiphat  of  lime  is  found  in  the  neighbour- 
hood of  the  spring. 

Salies,  to  the  south  of  Toulouse,  in  the 
department  of  the  Upper  Garonne. 

Salins  and  Montmorot,  in  the  depart- 
ment of  the  Jura.  In  the  first  of  these 
two  the  water  contains  about  0.15  of  salt. 

Dieuze,  Moyenvoe,  and  Chateau-Salins, 
in  the  department  of  the  Meurthe.  These 
contain  upon  an  average  about  0.13  of 
salt.  These  springs,  of  which  there  are 
about  twenty,  are  at  no  great  distance 
from  one  another  :  the  first  are  at  the  foot 
of  the  chain  of  Jura,  the  second  at  the 
foot  of  the  Vosges.  The  product  of  these 
brine-springs  supplies  Switzerland  with 
salt. 

Montiers,  in  the  department  of  Mont- 
Blanc,  and  consequently  in  the  midst  of 
the  higher  Alps. 

In  the  same  department,  near  St.  Mau- 
rice, is  the  salt  rock  of  Arbonne,  which 
is  at  a  considerable  elevation,  being  near 
the  region  of  perpetual  snow.  This  is  a 
gypseous  stone  impregnated  with  muriat 
of  soda :  the  salt  is  extracted  by  solution 
in  water,  and  the  insoluble  matter  re- 
mains porous  and  light. 

Near  Lampertsloch,  in  the  department 
of  the  Lower  Rhine,  are  the  salt-springs 
of  Sultz ;  and  in  the  department  of  the 
Rhine  and  Moselle  are  those  of  Kreutz- 
nach. 

Besides  these,  other  brine-springs  are 
mentioned,  of  which  no  use  has  been 
made,  in  the  department  of  Cote  d'Or  ;  a 
small  salt-lake  near  Courthezon,  in  the 
department  of  Vaucluse ;  and  several 
brine-springs,  which  are  now  neglected, 
in  the  department  of  the  Lower  Alps,  be- 


tween Castcllane  and  Tallard.  There  arc 
some  also  in  the  department  of  the  Yonne, 
at  Andreaux  and  at  Camarade  ;  in  the  de- 
partment of  the  Arriege ;  and  in  other 
places. 

The  only  mines  of  rock-salt  in  England 
are  those  in  the  neighbourhood  of  North- 
wich  in  Cheshire.  Thesejwere  discovered 
1670.  The  first  stratum  of  salt  occurs  at 
the  depth  of  about  forty  yards.  The  stra- 
ta vary  in  thickness,  are  of  a  wavy  struc- 
ture, and  alternate  with  strata  of  clay,  un- 
der which  they  are  found.  The  salt  is  in 
some  places  red,  in  others  transparent. 
The  ground  over  them  consists  of  strata 
of  red-clay,  coarse-grained  sandstone, 
blue  clay,  suiphat  of  lime,  and  indurated 
clay.  These  mines  are  the  most  produc- 
tive of  any  in  the  world.  The  salt  is 
worked  by  running  galleries  into  the  stra- 
ta, and  leaving  pillars  of  it  to  support  the 
root,  symetrically  arranged,  which  gives 
the  whole  a  beautiful  appearance.  It  ap- 
pears to  be  free  from  suiphat  of  lime. 

The  brine-springs  were  known  long 
before  the  rock-salt  was  found.  When 
the  miners,  in  searching  for  them, 
bore  through  the  stratum  of  clay  that 
lies  over  them,  they  spring  up  with  great 
force 

Germany  abounds  in  salt,  particularly 
in  the  dissolved  state,  or  brine-springs. 
These  occur  almost  every  where,  from 
Westphalia  and  the  shores  of  the  Baltic, 
through  Pomerania,  into  Swabia  and  Au- 
stria. About  sixty  are  mentioned,  which, 
supply  the  general  consumption  through- 
out Cermany.  Of  these  the  following  are 
the  chief,  proceeding  from  north  to  south, 
and  from  west  to  east. 

In  Westphalia,  the  brine-springs  of 
Rehme,  not  far  from  the  Ems.  These  are 
situate  in  a  plain.  Their  water  is  concen- 
trated by  graduation. 

In  the  circle  of  Lower  Saxony,  the 
springs  of  Lunenburg,  in  the  city  of  the 
same  name,  in  the  electorate  of  Hanover. 
These  waters  do  not  require  to  be  con- 
centrated by  graduation,  and  they  afford 
no  suiphat  of  lime ;  which  is  the  more 
surprising,  because  there  are  hills  of  sui- 
phat of  lime  near  the  springs. 

Near  Brunswick  is  the  salt-spring  of 
Saltzdalen.  The  spring  is  at  the  depth  of 
seventy  yards. 

Among  the  brine-springs  in  the  duchy 
of  Magdeburg,  those  of  Halle  are  to  be 
remarked.  Their  waters  are  sufficiently 
rich  in  salt,  not  to  require  the  process  of 
graduation  to  concentrate  them. 

In  Upper  Saxony,  in  the  county  of 
Mansfeldt,  are  the  brine-springs  of  Ar- 
tern,  six  leagues  from  Eisleben.  These 
afford  about  two  thousand  tuns  a  year. 


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SAL 


A  great  deal  of  sulphat  of  lime  is  depo- 
sited by  them. 

In  Prussian  Pomerania  is  that  of  Col- 
berg;  and  in  Swedish  Pomerania,  that  of 
Greifswald,  on  the  shores  of  the  Baltic 
sea. 

In  the  circle  of  the  Upper  Rhine,  in 
Hesse,  are  the  brine-springs  of  AUendorff, 
on  the  Werra. 

In  Franconia,  toward  the  northern  part 
of  the  circle,  are  those  of  Kissingen  and 
Scmalkalde. 

It  is  to  be  observed,  that  many  of  these 
brine-springs  are  included  within  a  circle 
of  about  a  hundred  miles,  of  which  the 
city  of  Hanover  is  the  centre.  In  the 
plains  at  the  foot  of  the  mountains  of  the 
Hartz  and  Thuringervvald,  no  mines  of 
rock-salt  have  been  found. 

We  must  now  proceed  to  the  south  of 
Germany,  leaving  the  mountains  of  Bohe- 
mia, with  the  circles  of  Upper  Saxony 
and  the  Upper  Rhine,  to  the  north,  before 
we  meet  with  any  more  salt  In  fact,  there 
are  salt-mines  or  brine-springs  in  Swabia, 
Bavaria,  the  Tyrolese,  the  electorate  of 
Saltzburg,  and  Upper  Austria. 

The  mines  of  Tyrol  are  situated  in  a 
very  high  mountain,  two  leagues  from  the 
City  of  Halle,  on  the  river  Inn,  near  Inn- 
spruck.  The  sal  gem  there  forms  an  ir- 
regular mass,  including  fragments  of  the 
.schist,  the  vxtcke  of  Werner,  which  forms 
the  base  of  the  mountain. 

The  salt  here  is  wrought  in  a  peculiar 
manner.  Parallel  galleries  are  run  into 
the  mass ;  in  these  galleries  dikes  are 
formed,  and  water  is  let  into  them,  where 
it  remains  from  five  to  twelve  months. 
When  the  water  is  saturated,  it  is  drawn 
off  by  pipes,  and  the  solution  is  evapo- 
rated. 

In  the  circle  of  Austria,  the  salt  mine  of 
Hallein,  on  the  Salza,  in  the  electorate  of 
Saltzburg,  is  one  of  the  richest  in  Germa- 
ny. The  mountain  that  includes  it,  is  com- 
posed of  saline  schists,  which  are  wrought 
like  those  of  Halle  in  the  Tyrolese  just 
mentioned ;  but  the  water  is  suffered  to 
stand  on  the  salt  only  two  or  three  weeks. 
No  pillar  is  left  in  the  vast  cavern  formed 
by  the  galleries,  that  have  been  cut  into 
it  successively. 

The  salt-mine  of  Berchtesgaden,  near 
the  former  two,  is  wrought  in  a  similar 
manner,  but  it  contains  more  sal  gem  in 
mass. 

At  Reichenhall  there  are  thirty -four 
brine-springs,  containing  from  one  part 
and  an  half  to  thirty  parts  of  salt  in  a  hun- 
dred of  water,  from  all  of  which  salt  is 
extracted. 

Salt  is  found  likewise  at  Aussee,  in  the 
v  estern  part  of  Styria ;  and  near  it,  and  in 


Upper  Austria,  at  Gmuenden,  Hallstadt, 
and  Ischel. 

In  Switzerland  the  brine-springs  of  Bex, 
in  the  canton  of  Berne,  are  celebrated  for 
the  beauty  of  the  subterranean  works, 
that  have  been  executed  in  search  of  these 
deep  sources,  and  to  bring  them  to  the 
surface.  The  soil  in  which  they  are  found 
is  a  schistous  marl,  containing  some  slen- 
der veins  of  6al  gem.  It  appears  to  in- 
elude  large  blocks  of  carbonat  of  lime, 
and  to  be  itself  enchased  as  it  were  in 
beds  of  sulphat  of  lime  rendered  impure 
by  a  brown  clay.  The  surrounding  soil 
is  covered  with  the  same  sulphat  of  lime 
as  occurs  in  the  subterranean  excavations. 
Sulphur  has  been  found  in  the  carbonat  of 
lime.  These  brine-springs  require  gra- 
duation. 

In  Italy  brine-springs  are  mentioned 
near  Naples ;  and  in  Farther  Calabria, 
near  Altamonte,  at  the  foot  of  the  Apen- 
nines. These  springs  contain  sulphat  of 
lime  also. 

In  the  middle  of  the  Island  of  Sicily, 
and  toward  the  western  part,  there  are 
brine-springs,  near  Castro  Giovani,  Cala- 
tascibetta,  Regalmuto,  Cuttolica,  and 
other  places. 

It  appears  from  the  preceding  account, 
that  the  majority  of  brine-springs  and 
mines  of  rock  salt  are  found  at  the  foot  of 
high  mountainous  chains.  The  mines  of 
Transylvania,  Upper  Hungary,  Moldavia, 
and  Poland,  are  further  proofs  of  this  ge- 
neral principle.  These  mines,  which  are 
very  numerous,  and  important  with  re- 
gard to  their  extent,  the  vast  bodies  of 
salt  they  contain,  and  their  product,  are 
found  along  the  chain  of  the  Carpathian 
mountains,  and  spread  nearly  in  an  equal 
degree  on  each  side  of  the  chain.  They 
accompany  these  mountains  to  the  extent 
of  more  than  two  hundred  leagues,  from 
Wieliczka  in  Poland,  toward  the  north,  to 
Fokszian,  or  Rymnick,  in  Moldavia,  to 
the  south. 

The  strip  of  land  that  contains  the  salt- 
mines or  brine-springs  is  nearforty  leagues 
broad  in  some  parts.  In  it  may  be  reckon- 
ed about  sixteen  mines,  that  are  worked 
for  salt;  forty-three  indications  of  mines, 
that  have  never  been  wrought ;  and  four 
hundred  and  twenty  or  four  hundred  and 
thirty  brine-springs. 

The  most  remarkable  of  these  are,  be- 
ginning in  the  north-east  and  proceeding 
in  a  southerly  direction,  those  of  Wielicz- 
ka,  Bochnia,  and  Samber,  in  Poland;  and 
some  brine-springs  in  Buchovina  and  Mol- 
davia, particularly  near  Ockna.  On  the 
south-west  of  the  chain,  following  the 
same  direction,  are  those  of  Sowar,  near 
Eperies,  in  Upper  Hungary  j  of  Marma- 


SAL 


SAL 


rosch,  in  Hungary ;  of  Dees,  Torda,  Pa- 
raid,  and  Visackna,  near  Hermanstadt,  in 
Transylvania;  &c. 

The  salt-mines  of  Wieliczka,  near  Cra- 
cow, and  those  of  Bochnia,  which  appear 
to  be  a  branch  of  them,  are  celebrated 
from  the  accounts  given  of  them,  by  al- 
most every  traveller  in  that  country,  ma- 
ny of  whom  have  represented  them,  in 
too  strong  colours.  They  are  very  anci- 
ent, having  been  worked  ever  since  the 
year  1251.  In  other  respects,  they  have 
nothing  to  distinguish  them  above  others, 
except  the  extent  of  the  works  in  the  beds 
of  rock-salt,  the  dimensions  of  which  still 
remain  unknown.  The  ground  that  co- 
vers them,  is  composed,  like  that  over 
most  other  salt-mines,  of  alternate  strata 
of  sand,  marl,  pebbles,  and  marl  includ- 
ing large  blocks  of  salt.  Such  of  these 
blocks  as  are  first  found,  are  mingled  with 
clay,  and  called  green  salt.  The  purest 
salt  is  called  schibika.  These  mines  are 
about  two  hundred  and  eighty  yards 
deep 

In  the  mine  of  Bochina,  the  salt  pre- 
sents itself  in  a  stratum  at  once,  and  not 
in  detached  pieces.  The  strata  of  clay, 
as  well  as  those  of  salt,  are  undulated,  and 
not  of  a  uniform  thickness.  The  salt  is 
sometimes  brown,  at  others  reddish,  and 
at  others  transparent.  The  different  co- 
loured salt,  is  not  arranged  in  parallel 
layers.  The  strata  dip  at  an  angle  of  about 
forty  degrees,  with  the  horizon.  Town- 
son  informs  us,  that  very  beautiful  spe- 
cimens of  fibrous  muriat  of  soda  are  found 
in  it. 

At  Thorda,  the  mass  cf  salt  is  divided 
into  horizontal,  but  undulated  strata. — 
These  strata  are  two  or  three  centimetres, 
(near  eight  or  twelve  inches)  thick.  The 
lowest  are  the  most  undulated. 

You  go  down  into  the  sa  t-mines  of  Wie- 
liczka, by  six  shafts  of  foir  or  five  yards, 
in  diameter.  Various  structures  have 
been  formed,  in  the  body  cf  the  salt  itself. 
We  find  there  a  stable,  chambers,  and 
chapels,  all  the  parts  of  which,  as  pillars, 
altars,  and  statues,  are  of  salt.  The  shafts 
and  galleries,  are  perfectly  dry,  so  that 
you  are  more  incommoded,  with  dust  than 
dirt.  There  are  springs,  however,  both 
af  salt  water,  and  of  fresh,  in  these  mines. 
It  appears,  that  the  air  is  not  so  foul  in 
them,  as  in  most  salt  mines :  but  the  work- 
men do  not  reside  in  them,  as  some  have 
asserted.  In  certain  parts  of  the  mine, 
hydrogen  gas  sometimes  collects,  and 
takes  fire. 

The  salt  is  cut  out,  in  little  ascending 
steps.  It  is  formed  into  parallelopipedons, 
weighing  about  80  or  a  100  lbs.  or  into 


cylinders,  which  are  put  into  casks.  Thii 
mine  produces  about  six  thousand  tons  of 
salt  every  year. 

Near  Ockna,  in  Moldavia,  there  is  a  hill 
of  rock-salt,  in  many  parts  of  which,  the 
salt  appears  exposed  to  view. 

The  mines  on  the  south-east  of  the  Car- 
pathian chain,  appear  more  numerous, 
and  are  dispersed  through  a  greater  space 
of  ground,  than  those  of  the  north-east. 
They  are  in  general  very  near  the  surface 
Some  of  those  in  Transylvania,  are  so  to 
such  a  degree,  that  persons  are  appoint- 
ed, to  cover  the  salt  with  turf,  when  it  is 
washed  bare  by  the  rain.  These  masses, 
however,  are  so  thick,  that  their  bottom 
has  never  been  found.  If  they  be  not 
worked  to  the  depth,  of  a  hundred  and 
seventy  or  eighty  yards,  it  is  because  the 
extraction  of  the  salt,  becomes  too  ex- 
pensive. In  the  county  of  Marmaroch, 
they  have  been  wrought  to  the  depth  of 
upwards  of  two  hundred  yards.  These 
mines  contain  likewise  a  great  deal  of  pe- 
troleum ;  and  the  ground  in  which  they 
are  contained,  is  every  where  furrowed  by 
rivers.  The  mud  interposed,  between  the 
water  of  these,  and  the  salts,  is  imagined 
to  prevent  the  salt,  from  being  dissolved 
by  them. 

At  Paraid,  in  Transylvania,  there  is  a 
valley,  the  bottom  and  sides  of  which  are 
of  pure  salt  Walls  of  salt  appear  there 
60  or  70  yards  high. 

The  mine  of  Eperies,  is  three  hundred 
and  sixty  yards  deep. 

In  the  salt-mines  of  Marmarosch,  water 
has  been  found  included  in  the  substance 
of  the  salt  rock. 

The  mines  on  the  south-west  of  the 
Carpathian  mountains,  are  generally 
wrought  by  means  of  shafts.  There  are 
at  least  two  to  each  mine  ;  one  for  the 
workmen,  the  other  for  drawing  up  the 
salt.  The  salt  is  cut  out  in  ascending- 
steps,  which  produces  empty  spaces  of  a 
conical  form,  in  the  midst  of  the  strata. 
The  ladders  reach  perpendicularly  to  the 
bottom  of  this  conical  space,  so  that  with- 
in it,  they  stand  perfectly  detached.  Thus 
the  greater  part  of  the  body  of  salt  is  ex- 
tracted, leaving  empty  spaces,  which  are 
conical,  and  which  communicate  with  one 
another,  by  means  of  galleries.  It  has 
been  thought,  that,  in  order  to  leave  less 
salt,  it  would  be  better  to  give  these 
spaces  the  shape  of  a  parabola,  or  rather 
even  a  square,  with  vertical  walls  meet- 
ing together,  in  the  form  of  an  ogee.  The. 
salt  is  so  plentiful,  that  the  miners  are 
paid  only  for  such  pieces,  as  weigh  up- 
ward of  eighty  pounds  ;  the  others  being* 
rejected  as  useless.  When  the  workmen 


SAL 


SAL 


are  incommoded  by  water,  it  is  drawn  up 
in  leathern  bags,  to  be  emptied  out  of  the 
mine* 

The  Transylvanians  and  Moldavians, 
extract  salt  from  their  brine-springs,  by 
throwing  the  water  on  wood  fires,  as  the 
Gauls  and  Germans  did,  in  former  days. 

No  salt-mine  or  brine-spring  is  known 
either  in  Sweden  or  in  Norway. 

There  are  a  great  number  of  both,  and 
particularly  of  salt  lakes,  in  Russia.  The 
latter  is  peculiar  to  that  country,  there 
being  no  salt  lakes  in  any  other  part  of 
Europe. 

Among  these  is  the  salt  lake  of  Tor, 
toward  the  northern  extremity  of  little 
Tatary. 

There  are  similar  salt  lakes  in  the  Cri- 
mea, which  appear  to  belong  to  the  same 
system. 

At  Balachna,on  the  banks  of  the  Wolga, 
are  some  very  rich  brine-springs. 

We  now  proceed  to  Asia. 

In  Russia  in  Asia,  we  find  the  brine- 
springs  of  Permia,  of  which  there  are  a 
great  number,  at  the  foot  of  the  mountains 
of  Poyas. 

About  80  wersts  from  Yena  Tayeoska, 
in  the  desert,  between  the  Wolga  and  the 
Ouralian  mountains,  there  is  a  mine  of 
rock-salt. 

In  the  government  of  Astracan,  to  the 
north  pf  the  Caspian  sea,  in  the  environs 
of  Orenburg,  and  in  the  country  of  the 
Bashkirians,  salt  lakes  are  very  common; 
and  the  water  evaporating  during  the 
summer,  the  salt  appears  chrystallized  on 
their  surface,  and  round  their  borders. 
WThen  this  water  is  highly  concentrated, 
it  has  a  deep  red  colour.  The  salt  formed 
in  them,  has  often  the  same  hue ;  and 
when  this  is  the  case,  it  diffuses  a  very 
perceptible  violet  smell. 

One  of  these  is  the  salt  lake  of  Elton, 
above  Astracan,  in  the  re-entering  angle 
formed  by  the  Wolga.  The  Kalmucks  call 
it  the  Golden  Lake,  because  of  its  red  ap- 
pearance, when  the  sun  shines  on  it. 

The  lake  of  Bogdo,  situate  near  this, 
yields  a  perfectly  white  salt,  free  from  sul- 
phat  of  magnesia,  and  preferred  to  that  of 
lake  Elton. 

Near  Astracan  too,  is  the  mine  oflletz- 
ki,  celebrated  for  the  quantity  of  salt  it 
furnishes.  The  salt  lies  at  no  great  depth, 
and  rests  on  a  very  hard  clay.  The  soil 
above  it  is  sandy,  and  full  of  holes,  con- 
taining water  saturated  with  salt. 

In  Siberia,  there  is  a  mine  of  rock-salt, 
on  the  right  bank  of  the  Kaptendoi ;  and 
on  that  of  the  Kawda,  are  fourteen  brine- 
springs.  Others  are  found  in  the  govern- 
ment of  Kolivan,  and  in  the  environs  of 
Irkutsk,  near  the  lake  Baikal,  in  the  cen- 


tre of  Asiatic  Russia.  Lastly,  the  coun- 
try near  the  Caspian  sea,  is  so  impreg- 
nated with  muriat  of  soda,  that  in  the  en- 
virons of  Gourief,  the  fogs  and  dew,  that 
settle  on  people's  clothes  and  on  plants? 
are  saline. 

Among  the  Mungal  Tatars,  the  soil  is 
so  thoroughly  penetrated  with  muriat  of 
soda,  that  the  people  lixiviate  it,  and  eva- 
porate the  solution,  to  obtain  the  salt. 

That  part  of  China,  which  borders  on 
Tatary  contains  salt  mines,and  the  ground 
is  strongly  impregnated  with  salt. 

Salt  is  found  in  the  same  manner, 
throughout  almost  the  whole  table-land 
of  Great  Tatary,  Tibet,  Indostan,  and  par- 
ticularly  Persia,  where  very  extensive 
plains  are  seen,  covered  with  saline  efflo- 
rescenses.  This  is  eminently  the  case 
near  Bender-Congo. 

The  isle  of  Ormus,  at  the  mouth  of  the 
Persian  Gulf,  appears  to  be  one  large  rock 
of  salt. 

This  substance  is  likewise  found,  in  so- 
lid masses  near  Balach,  on  the  eastern 
frontier  of  Persia  ;  in  the  environs  of  Ispa- 
han, in  Media;  in  the  mountains  that 
surround  Komm,  to  the  north  of  Ispa- 
han ;  8tc. 

In  California,  salt  is  found  in  a  very  pure 
state,  and  in  large  solid  masses. 

The  mountain  of  Xaragua,  in  the  island 
of  St.  Domingo,  affords  salt ;  and  in  the 
same  island  there  is  a  very  remarkable 
salt  lake,  about  twenty-two  leagues  in 
circumference,  called  Henriquelle.  The 
water,  which  is  inhabitted  by  lizards,  alli- 
gators, and  land  tortoises,  all  of  a  large 
size,  is  deep,  clear,  bitter,  salt,  and  of  a 
disagreeable  smell.  Near  the  middle  of 
the  iake  is  an  island,  about  six  miles  long 
and  three  broad,  well  stocked  with  goats, 
whence  it  has  the  name  of  Cabrito  Isl- 
and; and  in  this  island,  is  a  spring  of  fresh 
water. 

Salt  lakes  oc;ur  in  others  of  the  West 
India  islands. 

In  Peru,  there  are  several  mines  of  sal 
gem,  in  very  hard  masses.  What  is  re- 
markable in  their  position,  is,  that  they 
are  in  the  highest  part  of  the  country,  as 
for  instance  in  Potosi.  The  most  usual 
colour  of  the  salt,  is  a  jasper  violet. 

There  are  likewise  salt  plains,  in  South 
America.  One  of  great  extent  is  mention- 
ed, in  the  envii  ons  of  Lepis,  towards  the 
northern  extremity  of  Peru.  Another  in 
Chili,  in  the  provinces  of  Copiapo  and 
Coquimbo,  which  are  nearest  to  Peru. 
And,  lastly,  in  the  southern  extremity  of 
America,  near  St.  Julian's  Bay,  in  Pata- 
gonia, there  is  a  salt  marsh  two  miles 
long. 

These  are  the  principal  places  in  the 


SAL 


SAL 


globe,  where  salt  is  found.  It  occurs 
likewise,  but  in  less  quantity,  in  spring's 
of  mineral  water,  holding"  other  saline 
substances  in  solutiou,  such  as  those  of 
Balaruc,  Bourbon,  Bourbon-Lancy,  La- 
motte,  &c 

Though  salt  is  generally  used  in  small 
quantities,  its  use  is  so  general  and  con- 
stant, that  a  vast  quantity  is  consumed 
merely  for  seasoning  our  food.  A  still 
more  considerable  quantity  is  employ- 
ed, in  salting  various  kinds  of  provi- 
sion, chiefly  animal,  but  some  vegetable, 
to  preserve  it  for  use.  Considered  in  this 
light,  it  is  of  great  importance,  affording 
employment  to  a  number  of  persons,  and 
furnishing  several  articles  of  commerce. 
Hence  it  was  natural,  that  endeavours 
should  be  made  to  extract  it  as  cheaply 
as  possible,  in  every  place  where  na 
ture  offers  it  to  us,  with  bountiful  profu- 
sion. 

The  salt  springs  of  Onondago  and  Ca- 
yuga, in  the  sta.e  of  New- York,  furnish 
about  300,000  bushels  a  year  ;  and  the 
quantity  may  be  increased,  in  proportion 
to  the  demand.  Those  of  the  western 
states  and  territories,  supply  about  an 
equal  quantity ;  that  known  by  the  name 
of  the  Wabash  Saline,  which  belongs  to 
the  United  States,  making  now  130,000 
bushels.  Valuable  discoveries  have  also 
lately  been  made  on  the  banks  of  the  Ken- 
hawa.  But  the  annual  importation  of  fo- 
reign salt  amounts  to  more  than  three  mil- 
lions of  bushels,  and  cannot  be  superseded 
by  American  salt,  unless  it  be  made  along 
the  sea  coast.  The  works  in  the  state  of 
Massachusetts  are  declining,  and  cannot 
proceed,  unless  the  duty  on  foreign  salt 
should  again  be  laid.  It  is  necessary  to 
shelter  the  works  from  the  heavy  summer 
rains  by  light  roofs  moving  on  rollers. 
This  considerably  increases  the  expense  ; 
and  it  appears  that  the  erection  of  ten 
thousand  superficial  square  feet,  costs  one 
thousand  dollars,  and  that  they  produce 
only  two  hundred  bushels  a  year.  A  more 
favourable  result  is  anticipated  on  the 
coast  of  North  Carolina,  on  account  of  the 
difference  in  the  climate,  and  works  co- 
vering 275,000  square  feet  have  been  late- 
ly erected  there. 

Salt  has  also  been  obtained  by  the  eva- 
poration of  sea  water,  after  several  of  the 
European  methods. 

Muriat  of  soda  has  a  pure  saline  taste 
without  any  mixture  of  bitterness.  It  crys- 
tallizes in  cubes  when  obtained  by  slow 
evaporation  from  its  solution,  but  when 
procured  by  a  boiling  heat  (as  is  the  case 
with  most  of  the  salt  used  for  culinary 
purposes)  the  form  is  that  of  a  hollow  in- 
verted pyramid,  resembling  a  hopper,  and 

VOL.  II. 


is  made  by  a  successive  aggregation  of 
cubes  round  a  central  one,  whilst  floating 
on  the  surface  of  the  brine,  whilst  the  in- 
creasing bulk  of  the  mass  causes  it  gra- 
dually to  sink  lower  in  the  liquor. 

Common  suit  is  very  soluble  in  water; 
8  parts  of  the  Utter  will  dissolve  some- 
what less  than  3  of  salt  at  a  moderate 
temperature,  and  scarcely  any  more  is 
taken  up  at  a  boiling  heat;  so  that  no  salt 
can  be  obtained  from  a  hot  saturated  so- 
lution by  mere  cooling,  but  only  by  eva- 
poration of  the  fluid.  Salt  contains  but 
little  water  of  crystallization,  and  henc* 
when  thrown  in  the  fire,  or  suddenly  heat, 
ed,  it  decrepitates  or  flies  to  pieces  with 
a  crackling  noise.  If  heated  red  hot  it 
melts,  and  at  a  still  higher  temperature 
it  flies  off  in  the  form  of  de^se  white 
fumes,  but  is  not  decomposed  by  volatili- 
zation 

It  is  composed,  according  to  Kirwan,  of 
53  per  cent  of  soda,  and  47  muriatic  acid 
and  water,  and  the  quantity  of  real  acid 
is  such  that  100  parts  of  the  crystallized 
salt  decomposed  by  nitrat  of  silver,  will 
give  233^  of  luna  cornea,  of  which  the 
mere  acid  is  38.6.  It  must  be  observed, 
that  there  is  some  difference  in  the  ana- 
lyses of  different  chemists,  but  taking  the 
above  data  as  correct,  100  parts  of  crys- 
tallized muriat  .of  soda  will  contain  53  of 
soda,  38.6  of  acid,  and  8.4  of  wj^ter. 

Muriat  of  soda  may  be  decomposed  in 
a  variety  of  ways :  its  acid  is  readily  and 
totally  expelled  by  the  sulphuric  at  a  mo- 
derate heat:  its  alkali  may  be  procured 
by  a  variety  of  methods,  many  of  which 
are  used  in  the  great  way,  and  will  be 
shortly  described  at  the  end  of  this  ar- 
ticle. 

We  now  proceed  to  the  mention  of  me- 
thods by  which  are  procured  the  immense 
quantities  of  common  salt  employed  by 
man  in  almost  every  country  on  the  face 
of  the  globe. 

It  has  been  already  mentioned  that  na- 
tive salt  is  found,  either  solid,  under  the 
surface  of  the  earth,  or  dissolved  in  natu- 
ral brine  springs,  which  are  always  found 
in  the  neighbourhood  of  rock  salt :  or  it 
is  left  by  the  spontaneous  evaporation  of 
many  inland  lakes  and  pools  in  different 
parts  of  the  world:  or  lastly,  an  inexhaus- 
tible store  of  it  is  contained  in  the  waters 
of  the  ocean.  Sometimes  the  rock  salt  is 
found  sufficiently  pure  to  be  used  without 
any  preparation;  this,  however,  is  rare, 
for  by  far  the  greater  part  of  the  salt  used 
throughout  the  globe,  is  got  by  evapora- 
tion of  salt  water,  either  by  natural  or  ar- 
tificial heat,  or  often  by  both.  The  gene- 
ral process  of  making  salt  from  brine  by 
artificial  heat,  is  very  simple  and  obvious^ 
X  X 


SAL 


SAL 


being  little  else  than  putting  the  brine 
into  a  broad  shallow  iron  pan,  bringing  it 
to  a  boiling  heat  by  furnaces  underneath, 
and  continuing  the  evaporation  nearly  to 
dryness,  during  which  t  .e  salt  gradually 
separates  as  the  water  is  dissipated,  and 
is  afterwards  collected  and  gently  dried 
But  there  are  several  circumstances  re- 
lating to  salt-making  which  deserve  the 
attention  of  the  chemist,  and  require  to 
be  related  more  at  large. 

We  .shall  give  in  a  few  words  the  pro- 
cess of  salt  making  as  practised  in  Che- 
shire, England,  being  the  place  whence 
most  of  the  salt  used  in  that  country  is  ob- 
tained 

The  brine  is  first  pumped  up  from  very 
deep  wells,  by  powerful  machinery,  and  is 
discharged  in  a  large  pond  or  reservoir. 
If  the  brine  is  weak  in  salt,  it  is  generally 
strengthened  and  nearly  saturated  by 
throwing  in  a  quantity  of  the  more  im- 
pure rock  salt  dug  up  in  the  neighbour- 
hood, particularly  in  those  salt-works  that 
have  the  convenience  of  water-carriage 
from  the  pits.  There  is  a  considerable 
difference  in  the  purity  of  the  brine  from 
different  pits :  all  contain  a  small  portion 
of  earthy  salt,  chiefly  sulphat  of  lime,  and 
a  small  quantity  of  carbonat  of  lime  held 
in  solution  by  an  excess  of  carbonic  acid, 
and  frequently  also  a  little  carbonat  of 
iron.  The  purest  brine  is  perfectly  lim- 
pid, of  a  pure  saline  taste,  and  a  peculiar 
cold  green  hue.  This  last  indicates  the 
absence  of  iron,  for  when  even  the  small- 
est admixture  of  oxyd  of  iron  is  present, 
the  water  has  a  yellowish  cast,  and  the 
salt  made  from  it  never  acquires  that  de- 
licate blue  whiteness,  which  is  consider- 
ed as  a  criterion  of  its  perfection.  The 
salt-pans  where  the  brine  is  boiled  down, 
are  oblong  shallow  troughs  of  wrought 
iron,  usually  from  20  to  30  feet  long  and 
broad,  and  about  9  to  12  inches  deep. 
•They  are  set  strongly  upon  masonry,  over 
a  large  furnace,  the  flues  of  which  draw 
all  round  the  pan.  The  fuel  is  coal,  of 
which  there  are  many  pits  at  no  great  dis- 
tance. Each  pan  stands  in  a  small  cover- 
ed building,  with  a  pyramidal  roof,  form- 
ed o£  boards,  sloping  downwards,  but 
with  a  considerable  interval  between  each, 
so  as  to  keep  oft'  the  rain,  and  at  the  same 
time  to  allow  of  a  free  passage  for  the 
Steam  of  the.  boiling  brine. 

The  whole  process  of  boiling,  purify- 
ing, and  evaporating  the  brine,  is  perform- 
ed in  this  single  pan. 

The  brine,  after  standing  some  days  in 
the  reservoir,  is  pumped  into  the  pan. 
When  heated  to  about  100°  it  begins  to 
grow  turbid,  owing  to  the  deposition  of 
the  carbonat  of  lime  and  of  iron  (if  any)  J 


by  the  expulsion  of  the  carbonic  acid 
which  held  them  in  solution.  This  forms 
a  scum  on  the  surface  of  the  brine  which 
is  partly  removed  by  a  skimming  dish, 
but  much  of  it  falls  to  the  bottom,  and  if 
suffered  to  remain,  would  materially  in- 
jure the  quality  of  the  salt  To  clear  it 
out,  the  brine  is  evaporated  till  it  begins 
to  salt,  that  is,  till  a  portion  of  the  muriat 
of  soda  begins  to  separate,  and  this  falling 
to  the  bottom,  mixes  with  the  carbonat  of 
lime,  and  gives  it  a  body,  which  enables 
the  workman  to  draw  it  out.  This  is 
carefully  done,  and  the  sediment  thus  ob- 
tained (called  clearings)  is  thrown  away, 
which  from  a  pan  of  24  feet  by  27,  usually 
amounts  to  about  three  or  four  bushels, 
The  evaporation  is  tiien  continued  at  a 
boning-  heat,  and  the  salt  gradually  col- 
lects at  the  surface  and  falls  to  the  bot- 
tom in  beautiful  crystals  of  a  pure  and  de- 
licate white,  where  the  br  ine  is  good.  As 
the  process  advances  and  the  saU  collects 
in  quantity,  it  is  fished  out  from  the  bot- 
torn  of  the  pans  by  wooden  vessels,  and 
poured  into  large  hollow  wooden  cones, 
with  a  hole  at  bottom,  and  suspended 
round  the  side  of  the  pans.  Here  it  drains, 
and  the  drainings  drop  again  into  the  pans. 
When  the  process  is  completed,  and  the 
contents  of  the  pan  evaporated  almost  to 
dryness  (which  usually  takes  a  single  day 
and  a  night)  the  cones  full  of  the  salt  are 
taken  to  a  large  room  made  very  hot  by 
stoves,  where  they  remain  till  thoroughly 
dry. 

The  grain  of  the  salt  is  determined  by 
the  rapidity  of  the  evaporation  and  the  de- 
gree of  heat  used.  In  the  common  salt- 
making  the  water  is  evaporated  at  a  full 
boiling  heat,  that  is,  as  fast  as  possible, 
and  hence  the  grain  is  small,  and  the  salt 
comparatively  soft.  The  contents  of  a 
single  pan  are  usually  worked  off  in  twen- 
ty-four hours,  except  from  Saturday  to 
Monday,  when  two  days  are  taken,  and 
hence  a  larger  and  harder  grained  salt  is 
made,  which  is  much  esteemed  in  the 
country  for  salting  cheese. 

It  is  found  by  experience,  that  some 
brines  will  not  readily  salt  by  mere  eva- 
poration, but  that  some  addition  is  re- 
quired to  make  them  work  well,  and  the 
salt  fall  regularly.  This  addition  is  gene- 
rally calves'  feet  jelly,  sometimes  glue, 
sometimes  white  of  eggs,  sometimes 
blood,  and,  in  short,  any  animal  or  vege- 
table mucilage  seems  to  answer  the  pur- 
pose. It  is  usual  to  have  standing  in  a 
corner  of  the  pan  an  earthen  vessel,  con- 
taining eight  or  ten  pay"  of  calves'  feet,  to 
which  hot  brine  is  added  to  extract  the 
jelly :  and  after  the  clearings  are  removed 
and  the  brine  begins  to  salt,  the  workman. 


SAL 


SAL 


adds  a  little  of'  the  jelly  at  discretion. 
The  precise  use  of  this  addition  is  by  no 
means  obvious,  nor  is  it  absolutely  neces- 
sary, but  long  experience  has  shewn  it  to 
be  useful  in  many  kinds  of  brine. 

Another  difficulty  sometimes  arises.  In 
general  the  brine,  when  it  has  once  begun 
to  salt,  goes  on  to  work  well  to  the  last, 
every  pari  of  the  surface  being  sufficient- 
ly covered  with  small  crystals  of  salt, 
which  soon  grow  into  a  group,  forming  a 
small  floating  island  of  salt,  which  soon 
sinks  to  the  bottom  by  its  own  weight, 
and  leaves  a  clear  surface  above,  which 
again  is  covered  in  the  same  manner.  But 
sometimes  from  some  unknown  cause,  a 
thick  shapeless  crust  of  salt  forms  rapidly 
over  the  whole  pan,  which  soon  hardens 
to  a  dry  floating'  cake  of  salt,  preventing, 
in  a  great  measure,  the  escape  of  the 
steam,  and  materially  retarding*  the  pro- 
cess. To  remedy  this,  a  small  lump  of 
butter,  not  more  than  about  half  an 
ounce,  is '  thrown  into  the  pan,  which 
quickly  melts  and  diffuses  itself  over  the 
dry  cake  of  salt,  and  causes  it  to  break 
up  and  sink,  after  which  the  salting  goes 
on  well. 

After  the  brine  has  been  evaporated 
nearly  to  dryness,  and  indeci.  during  the 
latter  part  of  the  boiling,  there  is  deposit- 
ed on  the  bottom  and  sides  of  the  pan,  a 
hard,  white,  saline  and  earthy  crust,  which 
strongly  adheres  to  the  pan,  and  is  partly 
fused  to  its  surface  by  the  intensity  of  the 
fire,  in  proportion  as  the  sides  become 
dry  by  the  loss  of  liquid. 

This  crust  daily  accumulates,  and  pro- 
duces much  inconvenience,  partly  by  in- 
juring the  quality  of  the  salt,  but  chiefly 
by  increasing  the  distance  between  the 
fire  and  the  brine,  and  forming  a  thick 
coating  through  which  the  heat  pene- 
trates with  difficulty.  Hence  it  becomes 
necessary  about  once  a  month  to  discon- 
tinue the  boiling  for  a  day,  and  to  pick 
and  beat  off  this  crust  with  hammer  and 
chissel,  often  to  the  great  injury  of  the 
pan  itself.  The  pickings,  or  pan-scratch, 
as  they  are  also  called,  are  thrown  away. 
Their  analysis  will  be  mentioned  after- 
wards. 

A  very  large-grained  and  beautiful  salt 
is  made  at  Liverpool,  and  some  other 
places,  by  very  slow  evaporation  of  satu- 
rated brine,  and  strings  or  sticks  are  put 
into  the  pan,  on  which  the  cr)stals  form, 
as  in  the  making  of  sugar-candy.  This 
salt  is  used  in  the  curing  of  fish,  and  is 
called  fishery-salt. 

The  chemical  analysis  of  the  different 
brines,  and  products  or  impurities  in  salt- 
making,  will  be  presently  mentioned. 

As  the  greatest  inconvenience  in  salt- 


making  is  the  precipitation  of  the  earthy 
impurities,  and  the  difficulty  of  prevent- 
ing them  from  mixing  with  the  salt,  a 
plan  has  lately  been  adopted  (under  pa- 
tent) in  some  works,  of  heating  the  brine 
in  a  separate  pan  to  the  degree  at  which 
the  earthy  carbonats  precipitate,  before  it 
is  sent  into  the  large  salting  pan.  It  is 
found,  that  the  same  fire,  by  extending 
the  flues,  will  heat  this  preparing  pan, 
which  is  contiguous  to  the  other,  and  the 
time  in  which  one  pan-full  is  worked  off, 
is  sufficient  to  bring  the  fresh  portion  to 
the  requisite  heat,  and  to  purify  it  consi- 
derably. 

When  a  weak  brine  is  exposed  to  the 
atmosphere,  the  watery  part  gradually 
evaporates,  and  with  it  the  carbonic  acid 
which  it  contains,  the  effect  of  which  is  to 
concentrate  the  solution  and  also  to  cause 
the  deposition  of  the  earth  and  oxyd  of 
iron,  which  the  carbonic  acid  held  dis- 
solved. As  evaporation  much  depends 
on  the  surface  exposed  to  the  air,  a  very 
ingenious  method  has  been  adopted  of 
promoting  this,  by  causing  the  weak  brine 
to  fall  successively  through  large  bundles 
of  faggots,  whereby  a  vast  consumption  of 
time  and  fuel  in  the  subsequent  evapora- 
tion is  prevented.  This  operation  is  call- 
ed graduation,  and  the  place  in  which  it  is 
performed  a  graduating  house. 

This  consists  of  a  very  long  range  of 
rows  of  faggots  placed  perpendicularly, 
and  rising  to  the  height  of  about  25  feet, 
and  disposed  in  cones,  the  summits  of 
which  are  about  6  feet  in  diameter,  and 
the  bases  about  10.  Just  above  the  fag- 
gots is  a  trough  perforated  with  holes  at 
small  intervals,  furnished  with  stop-cocks, 
and  the  whole  is  covered  with  a  pent- 
horse  roof.  At  the  bottom  of  the  faggots 
is  another  trough  to  catch  the  brine.  The 
length  of  these  houses  is  determined  by 
the  quantity  of  brine  wanted,  sometimes 
it  is  enormous.  In  some  parts  of  Germa- 
ny there  are  graduating  houses  six  thou- 
sand  feet  long ;  but,  in  general,  they  are 
from  200  to  1000,  as  will  be  more  fully 
noticed. 

The  weak  brine  is  first  raised  by  pumps 
to  the  upper  trough,  when  the  stop-cocks 
are  turned,  and  the  water  made  to  fall 
like  a  shower  of  rain  through  the  faggots 
into  the  trough  below.  It'  is  then  again 
forced  up,  and  undergoes  the  same  ope- 
ration successively  till  it  is  sufficiently- 
concentrated.  The  state  of  the  atmos- 
phere has  the  greatest  influence  on  the 
graduation  of  the  brine.  The  evaporation 
goes  on  the  quickest  in  a  dry  air  with  a 
moderate  wind:  when  the  wind  is  vio- 
lent, much  of  the  brine  is  carried  away  in 
the  state  of  spray  or  vapour,  particular .  j 


SAL 


SAL 


when  the  column  of  faggots  is  not  pyra- 
midal, but  has  the  same  dimensions 
throughout.  As  a  proof  of  this  waste, 
Haller  observes  that  in  the  neighbour- 
hood of  these  graduating  houses  the 
ground  becomes  in  a  few  years  covered 
with  the  salicurnia  and  other  plants  which 
are  known  to  require  a  salt  soil  and  flou- 
rish on  the  sea-shore. 

It  has  been  mentioned,  that  in  propor- 
tion as  the  brine  becomes  concentrated  it 
parts  with  its  carbonic  acid,  and  deposits 
carbonat  of  lime,  and  hence  the  faggots 
of  the  giaduaiing  houses  become  gra 
dually  encrusted,  over  every  twig,  with  a 
brown,  hard*,  earthy  matter,  consisting 
chiefly  of  carbonat  of  lime.  Thus,  in  a 
course  of  years,  the  faggots  are  entirely 
covered  with  stalactite  as  in  the  common 
petrifactions,  and  the  surfaces  for  evapo- 
ration become  thereby  so  much  diminish- 
ed, that  it  is  necessary  to  replace  them 
with  fresh  faggots.  The  time  that  one 
set  of  faggots  will  last,  is  about  eight  or 
ten  years. 

The  effect  of  graduation  in  concentra- 
ting brine  is  very  striking  Baron  Haller, 
in  his  valuable  memoir  on  the  subject, 
gives  the  result  of  many  observations  on 
this  and  other  particulars  relating  to  the 
salt-works  in  Switzerland,  of  which  he 
was  the  director. 

The  brine  springs  in  that  country  sel- 
dom contain  more  than  one  per  cent,  of 
salt  in  the  natural  state,  but  by  mere  gra- 
duation the  brine  is  brought  as  high  as 
20  per  cent  after  which  it  is  ready  to  be 
boiled  down  as  usual.  To  effect  this  con- 
centration therefore,  20  parts  of  brine 
must  part  with  19  by  evaporation  through 
the  faggots.  The  deposition  of  stalactite 
hardly  begins  till  the  brine  is  brought  to  5 
per  cent,  of  salt,  and  it  ceases  altogether 
when  it  is  brought  to  15  per  cent  The 
graduation  of  the  brine  becomes  slower 
as  the  concentration  increases.  With  re- 
gard to  the  actual  effect  of  a  given  quan- 
tity of  faggots,  Haller  finds  that  at  a  mean 
degree  of  concentration,  or  10  per  cent., 
the  evaporation  of  a  single  day  in  Swit- 
zerland, taking  the  average  of  the  entire 
year,  is  1 100  c  hie  feet,  (reckoning  the 
weight  of  the  cubic  toot  at  46  lbs  .of  18  oz.) 
in  a  row  of  faggots  20  feet  high,  and  735 
long.  When  the  sun  shines  strongly,  the 
exhalation  is  more  than  double  the  above 
quantity. 

A  graduating  house  of  the  above  di- 
mensions is  estimated  to  have  always  at 
work  about  1,912,000  lbs.  of  brine,  and 
this  quantity  is  furnished  eleven  times  in 
the  year  to  the  boiling  pans.  There  ap- 
pear to  be  twro  inconveniences  in  gradua- 
tion ;  one,  which  is  but  trifling,  is,  that  the 


brine  extracts  at  first  some  colouring 
matter  from  the  faggots,  which  is  never 
totally  got  rid  of  in  the  subsequent  eva- 
poration, so  that  the  salt  has  a  little 
brownish  tinge.  The  other  is  more  se- 
rious, and  it  is  the  actual  loss  of  brine  by 
graduation,  either  when  the  wind  is  too 
violent,  or  the  process  managed  unskil- 
fully and  the  faggots  not  well  arranged. 
This,  in  some  salt-works,  is  estimated  as 
high  as  from  30  to  40  per  cent. 

Klaproth  has  some  valuable  experi- 
ments on  graduated  brines,  in  his  analysis 
of  the  salt  springs  of  Konigsborn,  which 
is  a  salt  mountain  extending  from  Pader- 
born  to  the  duchy  of  Cleves,  and  into  the 
bishopric  of  Munster.  The  brine  is  found 
much  stronger  the  deeper  it  is  drawn. 
That  obtained  at  50  feet  from  the  surface 
contains  only  1  1-4  to  2  percent,  of  salt; 
at  80  feet  it  is  2  3-4 ;  and  at  120  feet  it 
rises  to  3  1-4  or  3  1-2  per  cent. 

The  method  pursued  by  this  excellent 
chemist  in  the  analysis  of  the  brine,  may 
be  also  shortly  mentioned  as  a  direction 
to  the  reader  who  may  wish  to  repeat  the 
experiments. 

1.  Fifty  cubic  inches  of  brine  (each 
equal  to  290  grs.  of  distilled  water)  were 
evaporated  to  dryness  in  a  sand  heat,  and 
the  weight  noted. 

2.  The  residue  was  covered  with  alco- 
hol, and  digested  in  a  moderate  heat  for 
24  hours. 

3.  The  alcoholic  solution  was  poured 
off  and  evaporated  to  dryness,  and  fresh 
alcohol  poured  on  the  residue  in  order  to 
redissolve  all  the  salts,  except  the  small 
portion  of  common  salt  which  the  first  al- 
cohol had  taken  up.  The  last  alcoholic 
solution  was  then  evaporated  to  dryness 
and  the  residue  weighed. 

4.  The  dry  residue  from  the  last  alco- 
holic solution  consisted  of  muriat  of  lime, 
and  muriat  of  magnesia;  and  the  weight 
of  each  was  determined  in  the  following 
manner:  the  residue  was  dissolved  in 
water,  and  the  earth  precipitated  by  car- 
bonat of  soda.  This  earth,  well  washed, 
was  then  combined  with  sulphuric  acid  to- 
excess,  and  after  the  mixture  had  stood  a 
while  in  a  warm  place,  the  excess  of  acid 
was  absorbed  by  adding  carbonat  of  lime. 
The  solution  was  then  evaporated  consi- 
derably (removing  the  sulphat  of  lime  as 
it  was  formed)  and  then  exposed  to  exha- 
lation in  the  open  air,  whereby  the  sul- 
phat of  magnesia  was  separated  in  crys- 
tals. These  last  were  collected,  redis- 
solved  in  water,  decomposed  by  soda,  and 
the  magnesia  saturated  with  muriatic  acid 
and  evaporated  to  dryness.  It  was  then 
pure  muriat  of  magnesia,  brought  to  the 
state  in  which  it  existed  in  the  dry  residue 


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of  the  brine,  and  the  weight  of  the  muri- 
ated lime,  originally  mixed  with  it  was 
found  by  subtracting  the  weight  of  the 
muriat  of  the  magnesia,  from  that  of  the 
entire  alcoholic  residue. 

5.  The  dry  salt  remaining  after  the  se- 
paration of  these  earthy  muriats,  was 
then  dissolved  in  water,  and  filtered. 

6.  What  was  left  on  the  filter,  consist- 
ed of  stdphat  and  carbonat  of  lime,  and 
oxyd  of  iron.  When  weighed,  it  was  treat- 
ed with  muriatic  acid,  and  the  sulphat  of 
lime  left  on  the  filter.  Ammonia  was  add- 
ed to  separate  the  iron,  which  was  col- 
lected and  weighed. 

7.  The  clear  solution  of  No.  5,  might 
still  contain  sulphat  of  lime  ;  it  was  there- 
fore boiled  with  carbonated  soda,  when  a 
carbonated  lime  fell  down.  The  soda 
added,  was  then  neutralized  by  muriatic 
acid,  and  muriat  of  barytes  added,  which 
gave  a  precipitate  of  sulphat  of  barytes, 
shewing  therefore  the  existence  of  sul- 
phuric acid  in  the  brine,  which  must  have 
been  combined  with  the  lime,  obtained 
by  the  soda.  The  quantity  of  sulphat  of 
lime,was  inferred  from  the  united  weights 
of  the  carbonat  of  lime,  and  the  sulphat 
of  barytes,  and  from  the  quantity  of  the 
latter  "also,  it  was  proved  that  no  other 
sulphat  existed,  than  that  of  lime.  The 
same  was  also  shewn,  by  the  gradual  so- 
lution of  the  salt,  in  a  mixture  of  two  parts 
of  alcohol,  and  one  of  w  ater,  for  the  sul- 
phats  will  not  sensibly  dissolve  in  this 
mixture  without  heat. 

When  the  brine  is  boiled  down,  what 
remains  of  the  carbonat  of  lime,  in  it,  is 
precipitated  along  with  selenite  and  com- 
mon salt,  and  forms  that  hard  crust,  which 
adheres  so  firmly  to  the  pan,  and  has 
been  described  already  under  the  term, 
pickings  or  pan-scratch. 

The  mother  water,  or  liquor  left  in  the 
salt  pan,  after  all  the  salt  that  it  is  thought 
proper  to  work  off,  is  taken  out,  is  a  very 
dense  bitter  fluid.  Its  specific  gravity,  is 
as  high  as  1.213.  Fifty  cubic  inches 
yielded  by  evaporation,  5440  grains  of  dry 
salt,  composed  of 

Muriated  lime    ....  660 

 Magnesia    .    .  840 

Sulphat  of  lime  ....  100 
Common  salt   3840 


5440 

It  is  remarkale  that  the  muriated  mag- 
nesia, is  here  a  fourth  more  than  the 
muriated  lime,  whereas  in  the  brine, 
both  rough  and  graduated,  it  is  not  more 
than  one-thirtieth  or  one-fortieth  of  the 
muriated  lime.  Hence  much  of  the  lat- 


ter, must  be  decomposed  during  the  boil- 
ing, to  which  Klaproth  attributes  the 
strong  smell  of  muriatic  acid,  perceivable 
when  the  evaporation  is  nearly  compltt 
ed. 

A  very  full  and  accurate  account  of  all 
the  processes  employed  in  the  large  salt  - 
works of  Salins,  Moyenvic,  and  other 
brine  springs  in  Franche  Comte,  in  the 
South  of  France,  on  the  borders  of  Savoy, 
is  given  by  Nicolas,  who  examined  them 
on  the  spot. 

We  shall  not  transcribe  it  at  large  to 
avoid  repetition,  the  general  method  being 
that  already  mentioned,  viz.  of  concen- 
trating the  brine  by  graduation,  then 
boiling  down  in  iron  pans.  By  some  va- 
rieties of  practice,  and  other  circumstan- 
ces contained  in  this  valuable  memoir,  are 
worth  relating. 

The  brine  gives  by  analyses,  the  fol- 
lowing ingredients.  One  French  pound 
(of  16  Oc.  and  576  grs.  to  the  ounce)  con- 
tains of 

oz.  grs. 

Muriat  of  soda    ....  7  _  529 

Sulphat  of  lime  23 

Sulphat  of  soda  75 

Muriat  of  lime  and  magnesia  81 

Three  kinds  of  salt  are  made  at  Salins, 
namely,  large  grained,  small  grained,  and 
loaf-salt.  The  common  or  small  grained, 
is  that  which  is  made  at  a  boiling  heal, 
continued  to  the  last.  The  large  grained 
is  made  in  small  pans,  placed  contiguous 
to  the  boiling  pans,  and  supplied  by  the 
same  fire,  the  flues  being  continued  un- 
der them-  The  heat  in  these,  is  but  slow, 
and  the  evaporation  moderate,  which  al- 
lows the  salt  to  form  in  large  crystals. 
The  earthy-saline  scum,  which  forms 
during  the  boiling,  is  afterwards  lixiviated, 
to  extract  the  salt  which  it  contains.  The 
schlot  or  pickings  from  the  pans,  contains 
much  Glauber's  salt,  which  is  also  ex- 
tracted by  hot  water,  and  when  the  solu- 
tion is  so  far  concentrated,  that  it  would 
crystallize  by  cooling,  it  is  stirred  con- 
stantly till  cold,  which  makes  the  salt 
assume  a  needled  form,  like  the  common 
Epsom  salt,  and  it  is  sold  as  such. 

A  very  ingenious  plan  has  been  intro- 
duced here,  of  applying  the  principle  of 
evaporation  by  the  atmosphere,  not  only 
to  the  concentration  of  the  brine,  but  to 
the  actual  crystallization  of  the  salt  which 
it  contains.  For  this  purpose,  the  brine- 
after  common  graduation  on  faggots,  is 
heated  in  the  pan  till  it  begins  to  salt.  It 
is  then  conveyed  to  another  graduating 
house  about  250  feet  long,  divided  bv 
party  walls  into  six  arches.  These  sup- 
port troughs,  extending  the  whole  length 


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of  the  building",  and  furnished  with  pro- 
pel' holes  for  the  brine  to  fall  down.  The 
space  under  each  arch,  is  filled  with  40 
rows  of  endless  cords,  stretched  vertically 
on  wooden  frames,  each  of  which  contains 
25  double  cords,  parallel  to  each  other, 
and  about  three  inches  asunder.  The 
whole  building1  contains  6000  of  these 
double  cords,  about  three  or  four  lines  in 
diameter,  and  about  30  feet  long.  The 
flooring-  of  the  building  is  made  of  fir 
planks,  well  put  together,  and  gently  slop- 
ing to  one  end,  to  convey  the  brine  as  it 
falls,  into  a  large  reservoir,  from  which  it 
is  again  pumped  up  to  the  upper  trough. 
The  side  of  the  building  most  exposed  to 
the  weather,  is  protected  by  a  canvas. 
The  hot  brine  as  it  passes  from  the  boiler, 
is  sent  to  the  upper  trough,  and  then  falls 
down  every  one  of  the  cords  in  a  copious 
stream,  round  which  the  salt  gradually 
crystallizes  in  a  stalactical  form.  When 
the  crust  of  salt  forms  a  cylinder  from  two, 
to  two  and  an  half  inches  in  diameter,  it 
is  taken  off,  and  the  process  repeated. 
Each  operation  produces  from  3500  to 
4000  quintals  of  excellent  salt,  and  re- 
quires about  a  month  to  be  formed  ;  and 
as  this  work  can  only  be  carried  on  in  the 
height  of  summer,  the  cords  can  be  charg- 
ed no  more  than  twice,  or  at  the  utmost 
thrice  in  the  year. 

The  salt  is  broken  by  a  kind  of  move- 
able flail  set  in  a  frame,  in  which  each 
row  of  cords  is  placed  in  turn. 

The  country  of  Saltzbourg,  on  the  bor- 
ders of  the  Tyrol,  furnishes  a  vast  supply 
of  salt,  which  is  procured  from  a  large 
salt  mountain,  near  the  town  of  Hallein. 
No  brine  springs  are  found  here,  which 
is  a  remarkable  circumstance,  as  in  ge- 
neral the  neighbourhood  of  rock  salt 
abounds  in  water.  The  rock  salt  how- 
ever, is  not  worked  out  in  mass  in  this 
country,  but  an  artificial  brine  is  made  in 
the  following  manner. 

A  horizontal  gallery  is  cut  into  the 
mountain,  through  the  middle  of  the  rock 
s.dt,  from  50  to  200  fathoms?  in  length, 
five  feet  high,  and  four  wide.  This  gal- 
lery is  supported  above,  and  on  the  sides 
by  "planking,  and  the  opening  is  shut  up 
by  an  earthen  wall.  Fresh  water  is  then 
let  in  from  springs,  collected  on  the  up- 
per part  of  the  mountain,  till  the  whole 
gallery  is  filled.  In  two  or  three  weeks, 
the  water  by  resting  on  the  salt,  has  ac- 
quired 22  per  cent,  of  saltness,  after  which 
it  is  drawn  off  and  boiled  down  as  usual. 
This  process  is  then  repeated  as  often  as 
necessary,  till  by  degrees,  the  galleries 
by  the  gradual  solution  of  the  sides  and 
floor,  enlarge  into  vast  caverns.  The 


roof  never  enlarges,  which  is  rather  a 
singular  circumstance. 

The  sea  is  an  inexhaustible  source  of 
salt,  and  vast  quantities  of  it  are  made 
from  sea-water,  in  different  countries. 
Sea-water  is  but  a  weak  brine,  the  solid 
contents  of  which,  vary  in  different  parta 
of  the  world.  In  the  Baltic,  it  is  not  more 
than  one-fortieth,  in  the  British  Channel 
about  one-thirtieth,  and  taken  at  a  great 
depth  near  the  Equator,  it  is  about  one- 
twenty-third,  in  which  state,  its  specific 
gravity  is  1.0289,  according  to  Bergman, 
who  has  analized  it.  By  the  experiments 
of  this  excellent  chemist,  it  appears  that 
an  English  wine  pint  of  this  sea-water,  (of 
28.875  cubic  inches)  contained, 

grains. 

Of  Muriated  soda     .    .  241 
Of  Muriated  magnesia  .  65.5 
Of  Sulphat  of  lime    .    .  8. 

314.5 

A  small  portion  of  carbonated  magne- 
sia, also  separates  during  the  evapora- 
tion. 

Sea-water  therefore  contains  a  very 
large  proportion  of  other  saline  matters, 
besides  common  salt,  more  so  than  the 
common  brine  springs,  and  this  being 
chiefly  muriated  magnesia,  the  salt  pro- 
cured from  sea-water,  is  apt  to  be  bitter 
and  subject  to  deliquescence,  unless  a 
good  deal  of  pains  be  taken  in  the  boiling, 
or  unless  the  evaporation  be  conducted 
very  slowly.  There  are  several  ways  of 
getting  the  salt  by  sea-water :  in  warm 
climates,  this  is  done  altogether  by  the 
heat  of  the  atmosphere,  and  this  forms 
the  large  grained  strong  dry  salt,  called 
bay  salt,  which  is  preferred  to  any  other 
for  curing  provisions,  that  are  intended 
to  keep  for  any  length  of  time.  Bay  salt 
is  made  in  great  perfection  in  Spain  and 
Portugal,  by  the  Biscayans,  and  on  the 
Mediterranean  shores  of  France,  and  in 
the  Bahama  islands  in  the  West  Indies. 
The  process  is  simple,  and  requires  but. 
little  apparatus  of  any  kind. 

The  first  requisite  is  a  sea  marsh,  or 
shallow  artificial  pond,  near  enough  to 
the  sea,  to  be  filled  at  high  water.  A  level 
shore  must  therefore  be  chosen,  and  the 
soil  must  be  clayey,  to  retain  the  water. 
The  bottom  of  the  pond  is  then  laid  out 
perfectly  even,  and  beaten  hard  and 
smooth,  and  a  channel  with  flood-gates, 
is  cut  to  the  sea.  The  salt  pools  consist 
always  of  a  large  reservoir,  communicat- 
ing directly  with  the  sea  at  one  end,  and 
at  the  other  with  a  number  of  smaller 
pits  or  beds,  on  which  the  salt  is  made 


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The  water  is  first  evaporated  by  the  sun's  |  ter,  and  the  surface  of  the  sand  appears 
heat  considerably  in  the  reservoir,  and  |  covered  with  a  white  efflorescence.  It  is 
then  conveyed  to  the  salt  beds,  whieh  arc 
only  a  few  inches  deep,  and  in  which  the 
evaporation  is  completed,  also  by  the  sun 
and  wind,  and  the  salt  separates  first  in 
the  form  of  a  white  crust,  which  is  broken 
from  time  to  time,  to  expose  a  fresh  sur- 
face to  the  air.  The  concentrated  brine 
yields  salt  about  twice,  and  sometimes 
thrice  a  week  in  summer.  The  first  sa- 
line crust  that  forms,  is  small  grained, 
the  latter  large.  Bay  salt  has  generally 
a  little  tinge  of  colour,  green  or  brown, 
according  to  the  soil  on  which  it  is 
formed.  It  is  only  made  in  the  summer 
months. 

Another  way  of  making  salt  from  sea- 
water,  and  which  is  practised  much  on 
the  French,  and  other  coasts  of  temperate 
climates  ;  is  partly  by  the  atmospherical 
evaporation,  and  partly  by  boiling,  for  the 
summers  are  not  hot  enough  in  this  climate 
to  make  salt  by  mere  exposure  to  the  air 
The  general  mode  of  proceeding,  is  that 
already  mentioned,  that  is  to  say,  the  sea 
water  is  exposed  during  the  summer  in 
shallow  artificial  pools,  where  it  becomes 
highly  concemrated,  and  this  is  after 
wards  boiled  down  in  iron  pans,  in  the 
usual  mode.  This  way  is  adopted  large- 
ly in  Scotland,  and  in  a  few  parts  of  Eng- 
land, particularly  at  Lymington.  The 
mother  water  that  remains  after  the  most 
of  the  salt  has  been  extracted,  contains 
much  muriat  of  magnesia,  and  this  is  ad- 
vantageously converted  into  the  sulphat 
of  magnesia,  as  will  be  mentioned  under 
that  article. 

There  is  still  another  method  of  ex- 
tracting the  salt  from  sea-water,  which  is 
by  collecting  the  sand  that  has  been  re- 
peatedly moistened  by  the  sea-water  and 

dried,  and  lixiviating   it  in  reservoirs, 

where  it  forms  a  very  strong  brine,  which 

is  then  boiled  down  as  usual.  This  way  is 

much  practised  on  the  western  coast  of 

France,  particularly  in  Lower  Normandy, 

and  at  the  isles  of  Oleron  and  Rhe. 
The  spot  being  chosen  (which  should 

be  on  a  level  shore  with  a  clean  sand)  the 

necessary  buildings  are  erected,  namely, 

evaporating  pans,  store-houses,  covered 

sheds,  &c.  and  an  area  of  three  or  four 

acres  is  selected  a  little  below  the  level  of 

the  spring  tides  and  above  the  neap.  The 

surface  is  carefully  levelled  by  the  plough, 

and  rolled  smooth  and  hard.    It  is  then 

filled  to  the  height  of  several  inches  with 

sand  taken  from  the  edge  of  the  sea  at 

low  water,  and  the  sand  is  also  drenched 

with  sea-water  as  the  tide  flows  in.  It 

then  lies  exposed  to  the  sun  and  wind, 

which  soon  dissipate  the  superfluous  wa- 


then  turned  over  frequently  with  a  kind 
of  shove?,  changing  the  surface  several 
times  a  day  till  the  whole  is  thoroughly 
dry.    This  saline  sand  is  then  carried  to 
the  sheds,  and  the  process  repeated  with 
fresh  sand  till  a  large  quantity  is  collect- 
d,  which  generally  employs  the  whole 
summer.  To  make  the  salt,  the  dry  sand 
is  taken  out  of  the  sheds,  and  thrown  into 
small  round  pits  about  2^  feet  in  diame- 
ter, and  42  inches  deep,  the  bottoms  of 
which  are  lined  with  hard  rammed  clay 
mixed  with  chopped  straw,  to  prevent  the 
water  from  oozing  through.  The  sand  is 
then  covered  with  sea-water,  or  with  the 
weaker  ley  of  former  operations,  and  af- 
ter standing  some  hours  is  drawn  oft  into 
reservoirs  or  barrels,  whence  the  evapo- 
rating pans  are  immediately  supplied. 
The  sand  is  lixiviated  a  second  time,  and 
this  ley  is  reserved  for  a  fresh  portion  of 
sand.    The  boilers  are  of  lead,  about  3}2 
feet  square,  and  4  or  6  inches  deep.  They 
are  heated  with  wood  of  any  kind,  or 
sometimes  with  reeds,  and  a  boiler  of  this 
kind  is  worked  oft  in  from  two  to  three 
hours.    The  salt  ;s  raked  out  as  it  forms, 
and  drained  in  hollow  cones,  as  in  other 
places.     Three  pans  of  this  dimension 
yield  about  50  lbs.  of  sait. 

The  salt  procured  in  this  way  is  white 
and  small  grained,  but  it  is  very  apt  to  be 
damp,  and  is  a  weak-bodied  suit  little  fit 
for  preserving  animal  food  lor  an}-  length 
"  time. 

In  some  northern  countries  some  advan- 
tage is  made  of  the  effect  of  cold  in  con- 
centrating brine,  by  freezing  at  first  only 
the  more  watery  part,  of  course  leaving 
the  unfrozen  part  proportionally  richer 
in  salt.  The  winters  of"  this  country  are 
not  cold  enough  in  general  for  this"  pur- 
pose, but  it  is  used  occasionally  on  the 
Baltic  coasts.  The  cold,  however,  must 
not  be  too  intense,  otherwise  the  brine  it- 
self freezes.  Frozen  salt  water  is  not  in 
hard  solid  masses  like  fresh  water,  but  it 
is  soft  and  crumbly  or  rotten.  The  effica- 
cy of  this  method  of  concentrating  brine 
is  very  considerable. 

Though  much  of  the  French  sea-salt  is 
very  indifferent,  the  Dutch  refine  it  into  a 
very  excellent  salt,  which  is  used  in  pick- 
ling the  herrings  for  which  that  nation  is 
so  justly  famous,  and  which  trade  is  un. 
der  the  strictest  inspection  as  to  the  good- 
ness of  the  salt,  and  the  care  to  be  taken 
in  every  step  of  the  business.  It  is  not 
precisely  known  whether  the  Dutch  do 
any  thing  more  than  boil  the  salt  again, 
and  evaporate  slowly,  except  that  it  is  the 
constant  custom  when  the  brine  begins  to 


of 


SAL 


SAL 


salt,  to  add  a  small  quantity  of  very  sour 
whey,  which  is  found  by  experience  to  be 
a  very  important  addition.  » 

We  shall  now  communicate  some  of 
the  processes  more  minutely  ;  and  add,  at 
the  same  time,  a  tew  plates  representing' 
the  apparatus  and  machinery  used  in  the 
manufacture  of  salt. 

Plate  XIV.  exhibits  a  plan  of  a  set  of 
brine-pits. 

A,  A  The  great  reservoir,  into  which 
the  water  flows  through  the  sluice  a. 

B,  B,  B.  Tiie  second  reservoir.  Into 
this  the  water  enters  by  a  subterranean 
channel  at  6,  and  circulating  through  the 
several  divisions  in  the  direction  of  the 
shaded  line,  finds  its  exit  at  d. 

c,  c,  c,  c.  Narrow  banks  of  earth  sepa- 
rating the  divisions. 

C,  C,  C.  The  third  reservoir.  The  wa- 
ter, on  quitting  the  second  reservoir,  en- 
ters through  an  aperture  at  d  the  long  nar- 
row channel  at  d,  e,  ft  g,  h,  whence  it 
flows  into  C,  C,  C,  as  it  had  before  done 
B,  B,  B. 

D,  D,  D,  D.  The  fourth  reservoir,  into 
which  the  water  flows  as  shown  in  the 
plate  from  the  third  reservoir ;  and  from 
which  it  is  ultimately  distributed  among 
the  small  sauare  basins  E,  E,  E,  E,  E,  E, 
E,E. 

i,  i,  i,  i.  Heaps  of  salt  drawn  out  of  the 
basins  E,  E,  and  left  to  drain. 

K,  K.  The  salt  collected  together  in 
larger  heaps,  and  left  to  drain  still  more. 

The  water  of  the  sea  is  let  into  these 
reservoirs  in  the  month  of  March.  It  af- 
fords, as  is  apparenl.  a  vast  surface  for 
evaporation.  The  first  reservoir  is  intend- 
ed to  detain  the  water  till  its  impurities 
have  subsided,  while  at  the  same  time  the 
evaporation  commences  in  it.  From  this 
The  other  reservoirs  are  supplied,  as  their 
water  evaporates.  The  salt  is  considered 
as  on  the  point  of  crystallizing,  when  the 
water  begins  to  grow  red.  Soon  after  this 
a  pellicle  forms  on  the  surface,  which 
breaks,  and  falls  to  the  bottom.  Some- 
times the  salt  is  allowed  to  subside  in  the 
first  compartments,  sometimes  it  is  made 
to  pass  on  to  others,  where  a  large  sur- 
face is  exposed  to  the  air.  In  either  case 
the  salt  is  drawn  out,  and  left  upon  the 
borders  of  the  pans  to  drain  and  dry.  In 
this  way  it  is  collected  two  or  three  times 
a  week  toward  the  end  of  the  operation. 

The  salt  thus  obtained  partakes  of  the 
colour  of  the  bottom  on  which  it  is  form- 
ed ;  according  to  the  nature  of  which  it  is 
white,  red,  or  gray.  The  last  is  frequent- 
ly called  green  salt.  Sea-salt  has  the  in- 
convenience of  tasting  bitter,  if  used  iin- 
mediately  after  it  is  made.  This  is  owing 
to  the  muriat  of  Utye  and  sulphat  of  soda, 


with  which  it  is  contaminated.  By  expo- 
sure to  the  air  for  two  or  three  years  it  is 
in  part  freed  from  these  salts. 

In  the  second  mode  of  extracting  salt 
from  sea-water,  we  have  said,  a  very 
smooth  plain  of  sand  is  formed  on  the  sea- 
shore, at  such  a  height  as  to  be  covered 
only  at  spring  tides  In  the  interval  this 
sand  dries  in  part,  and  is  covered  with  a 
saline  efflorescence,  which  is  removed, 
and  set  by.  When  a  suffi.  ient  quantity 
of  this  is  obtained,  it  is  washed  in  pits 
with  sea-water,  which  thus  becomes  satu- 
rated with  salt  This  water  is  placed  in 
large  shallow  leaden  pans,  the  superflu- 
ous water  is  evaporated  by  the  help  of 
fire,  and  thus  fine  white  salt  is  obtained. 
This  process  is  followed  on  the  coasts  of 
the  department  of  the  Channel,  near 
Avranches. 

It  is  said  too,  that  the  sea-water  may 
be  concentrated  by  freezing,  the  part  that 
is  frozen  containing-  much  less  salt  than 
that  which  is  not:  but  in  this  way  it  can- 
not be  concentrated  beyond  sixteen  or  se- 
venteen degrees. 

The  process  of  congelation  cannot  be 
employed  for  brine-springs  that  contain 
sulphat  of  magnesia,  because  this  salt  de- 
composes the  muriat  of  soda  at  so  low  a 
temperature;  sulphat  of  soda  being  form- 
ed, with  muriat  of  magnesia,  a  deliques- 
cent salt,  that  impedes  the  crystallization 
of  the  muriat  of  soda,  and  injures  its  qua- 
lity. 

Another  process  was  employed  by  the 
Romans  in  their  salt  works  at  Cervia  and 
Qstia.  They  piled  up  the  salt  in  heaps, 
andf  burned  osiers  around  them.  This 
hardened  the  surface  of  the  salt  so  that 
it  had  the  appearance  of  being  vitrified, 
and  the  rain  that  fell  slid  off",  without  dis- 
solving any  of  the  salt.  The  water  in  the 
heap,  being  also  prevented  from  evapo- 
rating b}-  it,  carried  with  it,  as  it  drained 
off,  ail  the  deliquescent  salts,  and  thus 
rendered  the  salt  itself  mere  pure  and 
dry. 

Lastly,  at  Walloe,  in  Norway,  gradua- 
tion houses  are  employed  to  concentrate 
the  sea-water,  which  is  said  to  be  there  at 
five  degrees.  By  this  mean,  and  the  addi- 
tion of  a  little  Northwich  salt,  it  is  brought 
to  the  strength  of  thirty-two  degrees,  and 
evaporated  in  furnaces,  as  will  be  describ- 
ed below. 

When  the  water  of  brine-springs  is 
sufficiently  impregnated  with  salt  to  con- 
tain at  least  fifteen  parts  in  a  hundred  of 
water,  that  is  to  say,  is  at  fifteen  degrees, 
it  is  subjected  directly  to  evaporation. 
The  pans  or  basins  in  which  this  is  per- 
formed are  sometimes  of  lead,  but  more 
commonly  of  iron.    They  are  very  large, 


SAL 


SAL 


but  shallow.*  Their  bottom  Is  flat  and 
smooth,  though  composed  of  several 
pieces  ;  but  these  pieces  of  iron  have  pro- 
jecting edges  on  the  outside  of  the  pan, 
which  are'  fastened  together  by  screws, 
so  as  to  form  a  very  secure  and  even 
joint.  During-  the  evaporation,  sulphat  of 
lime  is  deposited,  which  must  be  removed 
with  care.  Little  flat  tin  puns  are  placed 
on  the  borders  of  the  large  pan  to  receive 
this,  and  are  removed  when  the  salt  be- 
gins to  crystallize  ;  but  this  method  is  in- 
sufficient. Toward  the  end  of  the  opera- 
tion the  salt  mixed  with  sulphat  of  lime 
begins  to  adhere  to  the  bottom  of  the 
pan,  and  forms  a  crust  not  easily  removed. 
Mr.  Nicolas  has  proposed,  to  dissolve  this 
in  water  holding  but  little  salt  in  solution. 

This  crust,  which  contains  a  great  deal 
of  sulphat  of  lime,  is  so  hard,  that  it  is 
frequently  thrown  away  as  useless.  Mr. 
Unger  has  turned  it  to  considerable  advan- 
tage, by  powdering  it  under  stampers,  and 
dissolving  the  salt  it  contains  in  some  of 
the  water  of  the  same  brine-springs,  which 
is  thus  rendered  much  stronger.  These 
crusts  are  produced  by  the  salts,  which 
the  water  lets  fall  on  that  part  of  the 
pan,  where  it  is  converted  from  the  liquid 
into  the  aeriform  state.  If  it  were  evapo- 
rated without  ebullition,  this  would  not 
take  place. 

Mr.  Cleiss,  inspector  of  the  salt-works 
of  Bavaria,  has  lately  introduced  at  Moy- 
envie  a  method  of  evaporation,  which  ap- 
pears to  prevent  most  of  these  inconve- 
niences. 

The  pans  are  composed  of  square  plates 
of  cast  iron,  of  4  millimetres  (1.573  line) 
in  thickness,  and  4.76  centimetres  (18 
inches)  long  on  each  6ide.  These  plates 
are  joined  by  their  edges,  which  are  turn- 
ed downward,  and  consequently  without 
the  pan  ;  and  they  are  firmly  united  by  a 
piece  in  the  form  of  a  square  gutter, 
which  receives  the  edges,  and  is  secured 
by  a  great  number  of  screws. 

An  evaporating-house  is  composed  of 
six  pans,  of  this  construction,  disposed  in 
two  rows ;  but  these  pans  have  different 
uses,  which  require  a  particular  arrange- 
ment. 

That  in  the  middle  of  the  back  row  is 
the  smallest ;  and  it  has  no  particular  fire- 
place, but  it  is  heated  by  the  junction  of 
the  chimneys  from  the  other  fire-places. 
The  salt  water  deposits  its  impurities  in 
this,  which  is  called  the  small  pan. 

From  the  small  pan  the  salt  water 
passes  into  the  graduating  pan,  which  is 
lower  than  the  first,  and  placed  in  the 
middle  of  the  front  row.  The  water  is 
there  kept  in  a  state  of  constant  ebulii- 

VOL.  II> 


tion,  is  concentrated  in  it  to  20  degrees 
of  the  hydrometer,  and  deposits  a  part  of 
its  sulphat  of  lime. 

From  the  graduating  pan  the  salt  wa- 
ter passes  into  the  preparing  pans,  which 
are  lower  than  it,  and  placed  at  the  two 
extremities  of  the  back  row.  In  these  it 
is  also  kept  constantly  boiling,  is  com- 
pletely concentrated,  and  deposits  all  its 
sulphat  of  lime.  It  is  then  passed  into 
the  crystallizing  pans,  which  are  still  low- 
er than  the  preparing  pans,  and  placed  at 
the  two  extremities  of  the  front  row.  In 
these  the  water  scarcely  boils,  and  the 
salt  crystallizes. 

Each  pan,  with  the"  exception  of  the 
small  pan,  has  a  particular  fire-place,  the 
chimneys  of  which  pass  round  the  sides 
of  the  pan,  and  unite  under  the  small 
pan,  by  which  means  there  is  little  heat 
lost. 

These  pans  are  placed  two  and  two  in 
chambers  of  wood,  the  joints  of  which 
are  well  secured,  and  by  which  they  are 
completely  surrounded.  These  chambers 
are  low,  and  their  ceilings  are  perforated 
in  the  middle  with  holes  terminating  in  a 
tube,  by  means  of  which  the  aqueous  va- 
pour is  dissngaged  with  rapidity.  The 
chambers  for  the  preparing  and  crystal- 
lizing pans  have  their  ceiling  pyramidal, 
or  in  the  form  of  a  hopper  reversed, 
while  that  for  the  small  pan  and  the  gra- 
duating pan  is  horizontal. 

The  saline  waters  are  passed  success 
sively  into  these  four  kinds  of  pans  ;  and 
the  workmen  go  into  the  chambers,  in  the 
midst  of  the  vapour,  to  open  the  commu- 
nications. This  operation  is  performed 
every  six  hours,  and  the  water  in  each  pan. 
is  restored  to  the  level  at  which  it  stood 
six  hours  before.  Every  three  hours  the 
salt  in  the  crystallizing  pans  is  collected, 
and  is  brought  with  scoops  to  elevations 
on  the  front  edge  of  the  crystallizing  pans, 
where  it  drains.  It  is  afterward  carried 
into  drying  rooms,  which  surround  the 
outside  of  the  chambers.  These  are 
spaces  covered  with  iron  plates,  and 
warmed  by  heat-tubes  leading  from  the 
fire-places. 

Once  a  week  they  take  away  the  sul- 
phat of  lime,  throw  out  the  mother-wa- 
ters, and  break  the  shell,  that  is  to  say, 
the  incrustations  of  salt  which  adhere  to 
the  bottoms  of  the  pans.  Every  three 
weeks  the  work  is  entirely  stopped,  to  re- 
pair the  pans,  an  operation  which  is  per- 
formed by  the  workmen  themselves. 

It  has  been  found,  that  this  method  of 
evaporation  affords  a  saving  of  more  than 
one  third  of  the  fuel. 

An  improvement  has  lately  been  made 

*  y 


SAL 


SAL 


j'n  this  process  at  Dieuse :  the  small  pan 
has  been  suppressed,  and  the  drying- 
rooms  have  been  replaced  by  auxiliary 
pans,  in  which  a  coarse  salt  is  made. 

The  heated  drying  rooms  are  useless, 
when  the  humidity  of  the  salt  arises  from 
the  muriat  of  lime  it  contains. 

Explanation  of  Plates  XV.  and  XVI. 

Fig.  1.  Plan  of  the  pans. 

No.  1.  Small  pan. 

No.  2.  Graduating'  pan. 

No.  3.  Preparing  pan. 

No.  4.  Crystallizing  pan. 

The  arrangement  of  the  plates  of  iron, 
which  compose  these  pans,  is  shown  in 
No.  2. 

a,  a.  Elevation  on  which  the  salt  is  pla- 
ced to  drain,  as  it  is  taken  from  the  crys- 
tallizing pans. 

6,  b,  b.  Wooden  partitions,  which  se- 
parate the  chambers. 

c,  c,  c.  A  raised  wooden  ledge,  which 
surrounds  the  pans. 

Fig.  2.  Section  of  the  evaporating 
chamber,  which  contains  the  pans  1  and 
2,  in  the  line  C,  D. 

r/,  d,  d.  Heat-tubes,  which  give  heat  to 
the  small  pan,  and  contribute  to  heat  the 
others. 

e,  e,  e.  Fire-place  for  the  pans. 

is  i,  i.  Pillars  of  cast  iron,  over  the  gra- 
tings g,  g,  g,  which  support  the  bottoms 
of  the  pans. 

h.  Wooden  chamber,  which  contains 
the  two  pans. 

I.  Opening  by  which  the  vapours 
escape. 

Fig.  3.  Section  of  the  evaporating  cham- 
ber, which  contains  the  pans  3  and  4,  in 
the  line  A,  B. 

a.  Elevation  on  which  the  salt  from  the 
crystallizing  pans  is  placed  to  drain. 

The  other  letters  indicate  the  same 
parts  as  in  the  preceding  figures. 

Fig.  4.  Method  in  which  the  plates  of 
iron  are  joined,  to  form  the  pans. 

a.  The  iron  plate. 

b.  The  iron  gutter,  which  receives  the 
edges  of  the  plates,  and  is  strong-ly  fas- 
tened with  screws. 

Pillars  of  cast  iron,  which  support 
the  bottom  of  the  pan. 

Sometimes  the  water  is  evaporated  to 
dryness,  but  this  is  rarely  done,  because 
for  this,  the  water  must  contain  no  muriat 
of  soda.    Commonly  the  mother-water  is  I 
left,  containing  chiefly  the  deliquescent  i 
salts,  which  are  muriats  of  lime  and  mag- ' 
nesia.    These  salts,  while  they  increase  j 
the  bulk  of  the  mother-water,  add  also  to 
the  consumption  of  fuel,  and  render  the 
salt  obtained  bitter  and  deliquescent. 

Mr.  Gren,  proposes  to  decompose  them 
in  the  large  way  by  the  addition  of  lime 


and  sulphat  of  soda.  In  this  case  two  sub- 
stances are  precipitated,  one  of  which  is 
insoluble,  the  magnesia ;  and  the  other, 
the  sulphat  of  iime,  is  but  little  soluble- 
The  saline  water  may  then  be  evaporated 
entirely,  and  the  salt  obtained  will  be 
pure  and  dry. 

Lastly,  to  save  fuel  is  always  made  an 
object  in  these  works.  The  form  of  the 
furnaces,  and  the  dimensions  of  the  pans, 
are  calculated  to  obtain  this  important  end. 

In  most  works  where  saline  waters  are 
evaporated,  a  smell  by  no  means  disa- 
greeable is  perceived.  This  appears  to 
arise  from  the  small  portion  of  bitumen, 
which  is  almost  always  mixed  with  salt  in 
its  mines. 

When  the  saline  waters  contain  but: a 
small  quantity  of  salt,  the  evaporation  of 
it  by  fire  in  its  natural  state  would  be  too 
expensive.  It  must  be  concentrated 
therefore  by  some  cheaper  mode. 

Now  it  is  well  known,  that,  to  promote 
and  accelerate  the  evaporation  of  a  fluid, 
it  should  be  made  to  present  a  large  sur- 
face to  the  air.  To  effect  this,  the  water 
is  pumped  up  to  the  height  of  nine  or  ten 
yards,  and  made  to  fali  on  piles  of  fag- 
gots built  up  in  the  shape  of  a  wall.  The 
water,  distributed  uniformly  over  these 
by  means  of  troughs,  is  minutely  divided 
in  its  descent ;  and  thus  experiences  a 
considerable  evaporation.  The  same  wa- 
ter is  frequently  pumped  up  twenty  times 
or  more,  to  bring  it  to  the  degree  of  con- 
centration necessary  This  operation  is 
called  graduating ,  and  the  piles  of  thorn 
faggots  thus  erected  are  termed  gradua- 
tion-houses. 

These  piles  are  covered  with  a  roof,  to 
shelter  them  from  the  rain,  are  made 
about  five  yards  thick,  and  are  sometimes 
more  than  four  hundred  yards  long. 
They  should  be  so  constructed,  diat  their 
sides  may  face  the  prevailing  winds. 

Plate  XVII.  represents  a  graduation- 
house  at  Bex,  with  the  improvements 
lately  made  in  it  by  Mr.  Fabre. 

A.  Transverse  section  of  the  building. 

B.  Longitudinal  section. 

c,  c,  c.  The  faggots  or  thorns,  piled  up 
in  two  tiers  below,  and  one  above. 

!7,  a.  Wooden  troughs,  to  distribute 
the  salt  water  over  these  faggots. 

C.  C.  Plan  and  perspective  view  of 
these  troughs. 

b,  by  b.  Angular  notches,  through  which 
the  water  runs  out  in  slender  streams, 
presenting  a  large  surface  to  the  aii . 

e.  Roof,  covered  with  tiles,  not  laid 
flat,  but  raised  so  as  to  admit  a  free  circu- 
lation of  air  between  them. 

d,  d.  Reservoir,  into  which  the  concen- 
trated salt  water  flows,  and  from  which  it 


SALT  WORKS. 

ruuu  xv. 


... ...  ■  ) 


saxtt  work 5. 


Bavarian  Method  of  evajw rating  Salt  Wat&y. 


J.n.Jeymoiu-  ji 


SALT  WOMS 

njt  xvu. 


Graduaticnrhoust 


SAL 


SAL 


j  pumped  up  to  the  troughs,  to  be  distri- 
buted afresh  over  the  faggots. 

The  state  of  the  air  has  a  considerable 
influence  on  the  celerity  of  the  concen- 
tration. A  cool,  dry,  and  moderate  wind 
is  favourable  to  it :  while  dull,  damp,  and 
foggy  weather  sometimes  even  adds  to 
the  quantity  of  water. 

As  the  water  is  concentrated,  it  depo- 
sits on  the  faggots  a  coat  of  selenite,  or 
sulphat  of  lime,  which  at  length  becomes 
so  thick,  that  their  place  must  be  suppli- 
ed with  fresh  ones. 

When  the  water  is  brought  to  six  or 
seven -and-t wen ty  degrees  of  the  hydrome- 
ter by  graduation,  the  evaporation  is  com- 
pleted in  pans,  as  has  been  described 

A  process  lias  been  adopted  at  Mon- 
ticr,  w  hich,  lessening  the  quantity  of  fuel 
employed,  renders  the  operation  less  ex- 
pensive. When  the  water  has  been  con- 
centrated by  graduation,  and  afterwards 
by  artificial  evaporation  so  as  to  #  be 
brought  to  about  thirty  degrees,  which  is 
near  the  point  of  saturation,  it  is  made  to 
flow  over  a  number  of  strings  hanging 
perpendicularly.  These  strings  acquire 
a  coating  of  salt,  which  is  removed  when 
about  two  inches  thick.  A  gathering  of 
salt  of  this  thickness  may  be  made  twice 
or  three  times  a  year. 

Lastly,  at  Artern,  in  the  electorate  of 
Saxony,  salt  has  been  endeavoured  to  be 
obtained  from  brine-springs  by  the  action 
of  the  sun  alone,  without  having  recourse 
to  fire.  The  water  is  concentrated  by  gra- 
duation :  it  is  then  exposed  to  the  sun  in 
very  shallow  wooden  vats,  raised  above 
the  ground,  and  provided  with  a  wooden 
roof,  which  may  be  put  on  or  taken  off'  at 
pleasure. 

Weak  saline  waters  may  be  graduated 
in  some  degree  by  leaving  them  to  stand 
in  deep  reservoirs.  In  this  way  the  lower 
part  of  the  water  is  sometimes  raised 
from  containing  no  more  than  one  per 
cent,  of  salt  to  contain  fourteen  per  cent. 

Such  are  the  principles  of  the  different 
methods  of  extracting  or  manufacturing 
salt.  In  its  common  state  it  is  in  the  form 
of  loose  granular  crystals.  These  should 
always  be  dry  :  if  they  be  not,  the  salt  has 
not  been  perfectly  freed  from  the  deli- 
quescent muriats,  with  which  it  is  often 
contaminated  in  its  natural  state,  and  con- 
sequently is  impure ;  or  water  has  been 
thrown  over  it  by  the  vender,  to  increase 
its  weight,  a  practice  which,  we  are  sorry 
to  say,  is  sometimes  followed  by  those, 
who  pay  more  regard  to  profit  than  to 
probity.  In  some  countries  it  is  formed 
into  loaves,  by  compressing  it  in  a  mould 
I  with  a  small  portion  of  water. 

The  value  of  salt  for  culinary  purposes 


is  well  known  :  it  is  likewise  of  peculiar 
service  in  preserving  the  health  of  cattle, 
and  particularly  in  preventing  that  most 
fatal  disorder  in  sheep,  the  rot.  Besides, 
salt  is  an  excellent  manure,-  as  it  is  equal- 
ly destructive  to  weeds  and  vermin  :  the 
most  accurate  proportion  appears  to  be 
sixteen  bushels  per  acre  ;  but,  if  that  quan- 
tity be  exceeded,  or  doubled,  it  will  pro- 
duce effects  diametrically  opposite  to 
those  intended,  and  completely  check  ve- 
getation. 

With  respect  to  its  medicinal  proper- 
ties, common  salt,  when  taken  in  small 
quantities,  promotes  the  appetite  and  di- 
gestion ;  but,  if  given  in  large  doses,  for 
instance",  half  an  ounce,  it  operates  as  a 
laxative.  It  deserves,  however,  to  be  re- 
marked, that  its  useful  properties  are 
greatly  changed  in  a  state  of  intimate 
combination  with  animal  matters  :  thus, 
salt-butter  and  salt-meat,  or  fish,  are  less 
wholesome  than  those  substances  when 
eaten  in  a  fresh  state,  with  a  due  propor- 
tion of  that  domestic  spice ;  nay,  if  used 
too  frequently,  the  former  often  lay  the 
foundation  of  tedious  maladies,  such  as 
leprosy,  scurvy,  and  other  cutaneous 
eruptions. 

In  addition  it  maybe  observed,  that  al- 
most all  graminivorous  animals  are  fond 
of  it,  and  that  it  appears  to  be  beneficial 
to  them,  when  mixed  with  their  food. 
Wood  steeped  in  a  solution  of  it,  so  as  v> 
be  thoroughly  impregnated  with  it,  is  ve- 
ry difficult  of  combustion  :  and  in  Persia 
it  is  supposed  to  prevent  timber  from  the 
attack  of  worms,  for  which  purpose  it  is 
used  in  that  country.  Bruce  informs  us, 
that  in  Abyssinia  it  is  used  as  money  :  and 
it  is  very  probable,  that  the  pillars  of  fos- 
sil glass,  in  which  the  Abyssinians  are 
said  by  Herodotus  to  have  enclosed  the 
bodies  of  their  relations,  were  nothing  but 
masses  of  rock-salt,  which  is  very  com 
raon  in  that  part  of  Africa. 

Salt  was  supposed  by  the  ancients  to 
be  so  detrimental  to  vegetation,  that, 
when  a  field  was  condemned  to  sterility, 
it  was  customary  to  sow  it  with  salt. 
Some  modern  agriculturists,  however, 
consider  it  as  a  useful  manure,  though  the 
experiments  on  this  point  do  not  agree. 
Probably  it  is  most  useful  in  this  waj' 
when  most  impure,  and  not  used  in  too 
large  a  quantity. 

The  practice  of  salting  ships  and  other 
sea  vessels  with  a  view  to  their  preserva- 
tion, says  l)r  Mease,  in  the  Archives  of 
useful  knowledge,  has  long  been  followed 
in  the  port  of  Philadelphia,  aijd  found 
highly  beneficial.  The  following  is  the 
mode  adopted : 

Pieces  of  boards  are  dove-tailed  be- 


SAN 


SAP 


tween  the  timbers  and  to  the  outside 
p'.anks  about  the  floor  timber  heads  :  al- 
so a  littie  above  the  listings  in  the  hold, 
and  lastly  above  the  listings  between 
decks.  After  the  vessel  has  been  water- 
ed in  order  to  discover  leaks,  the  water 
drained  off,  and  the  timbers  are  prepared 
for  ceiling,  let  all  the  spaces  between  the 
timbers  and  the  outside  and  inside  planks 
be  filled  with  salt,  and  drove  down.  The 
upper  rooms  must  of  course  be  filled  be- 
fore the  plank  shares  are  put  on.  The 
spaces  between  the  transoms  must  also 
be  filled. 

Salt  is  only  used  in  vessels  built  of  un- 
seasoned timber,  and  two  of  the  most  ex- 
perienced ship  builders  in  Philadelphia, 
gave  it  as  their  opinion  to  the  Editor, 
that  a  ihip  built  of  timber  fresh  cut  and 
salted  as  above  directed,  would  far  out- 
last a  ship  built  of  the  most  seasoned 
timber.  The  names  of  several  skips  built 
in  Philadelphia  in  1790,  1792,  and  since, 
of  unseasoned  timber,  and  salted,  were 
mentioned  as  being  sound  to  this  day. 

The  effect  of  the  salt  is  thoroughly  to 
penetrate  the  planks  and  timbers,  as  was 
evident  from  a  thick  incrustation  of  the 
salt  on  the  lining  of  the  cabin  of  a  ship 
thus  salted.  The  lining  was  five  inches 
thick  and  painted.  The  impregnation  of 
the  timbers  and  planks,  will  of  course 
cause  considerable  waste  of  the  salt,  and 
will  require  a  renewal  of  it  after  every 
voyage  One  ship,  (the  Coromandel,) 
builUn  1806,  of  349  tons,  required  575 
bushels  of  salt  on  the  stocks ;  300  bush- 
els on  her  leturn  from  Calcutta  in  about 
18  months  after  she  was  built ;  and  250 
bushels  since.  The  ship  Benjamin  Frank- 
lin, built  in  1795,  and  of  about  263  tons, 
required  350  bushels.  The  ship  Plough- 
boy,  of  287  tons,  built  in  1800,  took  316 
bushels.  Vessels  even  of  the  same  ton- 
nage will  require  more  or  less  salt,  as  the 
spaces  between  the  timbers  are  greater  or 
less. 

SALTING  MEAT.    See  Beef. 

SAXD. — Sand  is  an  assemblage  of  small 
stones.  It  is  usually  produced  by  the  me- 
chanical division  arising  from  agitation  in 
water.  All  stones  but  those  of  the  sili- 
ceous order  are  so  soft,  that  the  comminu- 
tion thus  produced  is  usually  carried  in 
them  to  an  extreme  degree,  so  as  to  form 
dust,  or  mud;  and  their  disposition  to 
unite  or  adhere  together  commonly  pro- 
duces stones  of  a  different  texture  from 
that  before  possessed  by  the  particles.  In 
this  way  it  appears,  that  chalks,  clays, 
marls,  and  other  consistent  matters  may 
be  formed  out  of  harder  or  more  symme- 
trical materials  worn  dov#i.  But  the  sili- 
ceous earth  being  not  only  very  hard,  but 


likewise  indisposed  to  adhere  together, 
retains  the  form  of  sand,  as  soon  as  the 
parts  have  become  so  small  as  to  be  defi- 
cient in  the  weight  requisite  to  enable  the 
parts  to  shake  and  break  each  other.  Sand 
is,  therefore,  always  understood  to  denote 
a  siliceous  matter. 

The  chief  uses  of  sand  in  chemistry  are 
in  compositions  for  pottery  and  glass. 
Some  sands  are  more  and  some  less  fusi- 
ble, according  to  the  various  hard  stones 
from  which  they  may  have  originated. 
The  size  of  the  particles  is  of  some  im- 
portance in  these  works.  As  an  alkali  in 
fusion  dissolves  siliceous  earths  in  less 
time  the  greater  the  surface  of  action,  or, 
which  is  the  same  thing,  the  finer  the  par- 
ticles of  sand,  this  kind  is  accordingly  pre- 
ferred for  vitrifications. 

SANDEVER. — This  is  a  saline  matter, 
which  rises  in  the  melting  pots  during 
the  fusion  of  silex,and  appears  under  the 
form  of  scum.    See  Glass-making. 

SAP,  or  Water  Colours,  are  of  that  na- 
ture, that  they  are  capable  of  being  en- 
tirely dissolved  in  water,  but  are  by  no 
means  miscible  with  oils.    They  are  of  a 
viscid  nature :  whence  they  stand  in  no 
need  of  any  cementing  substance,  neither 
do  they  dry  easiiy  for  this  same  reason, 
and  are  transparent.  All  colouring  juices 
and  extracts  inspissated  by  evaporation, 
may  be  used  with  this  intention  i  as,  for 
instance,  a  decoction  of  Brazil  wood  pre- 
pared with  alum,  and  inspissated  ;  extrae  t 
of  saffron,  refined  Brunswick  green,  crys- 
tallized verdigrise,  an  aqueous  extract  of 
litmus  with  the  addition  of  a  little  alkali, 
gamboge,  sap  green,  and  the  inspissated 
decoction  of- the  green  husks  of  walnuts. 
Of  these,  sap  green  is  prepared  from  the 
expressed  juice  of  buckthorn  berries  not 
perfectly  ripe  (Rhamnus  catharticus,  Lin.) 
by  gentle  evaporation  to  the  consistence 
of  honey.  The  sap  must  be  well  clarified 
before  it  is  evaporated.    When  it  is  in- 
spissated, as  much  alum,  or,  which  is  still 
better,  sugar  of  lead,  is  to  be  mixed  with 
it  by  little  and  little  over  the  fire,  as  is  re- 
quisite to  produce  the  finest  green  colour, 
A  redundancy  of  these  additions  is  preju- 
dicial. The  complete  exsiccation  must  be 
made  with  a  gentle  heat  in  saucers.  The 
litmus  above  mentioned,  which  however 
(  contains  a  blue  sap  colour,  is  prepared  in 
j  the  large  way  in  the  manufactories  of  Hol- 
j  land.  Ferber  gives  the  following  descrip- 
J  tion  of  it :  Archil  (Lichen  rocella)  is  to  be 
.  mixed  with  urine,  lime  water,  slaked 
|  lime,  and  some  potash,  in  several  large 
j  cisterns,  which  must  be  kept  under  shel- 
!  ter,  and  suffered  to  stand  for  several 
j  weeks.    By  this  means  the  mass  is  ren< 
dered  soft,  and  passes  over  to  a  kind  of 


SEA 


sp:a 


fermentation  or  evolution  of  its  particles, 
and  of  the  colouring  matter  contained  in 
them.  Now  and  then  it  is  stirred,  and 
suffered  to  stand  macerating',  till  the  mass 
is  become  quite  blue,  and  is  converted 
into  a  muddy  kind  of  pulp.  Upon  this  the 
w  hole  mixture  is  ground  in  a  mill  con- 
structed for  the  p\irpose,  and  the  pulpy 
magma  dried  in  moulds.  Hither  also  may 
be  referred  the  fine  sap-blue  discovered 
by  Dr.  Struve.  In  order  to  make  this,  a 
quarter  of  an  ounce  of  indigo  is  to  be  re- 
duced to  powder,  and  triturated  in  a  glass 
mortar,  with  two  ounces  of  good  oil  of 
vitriol.  After  this,  four  ounces  of  alum 
are  to  be  dissolved  in  warm  water,  to 
which  must  be  added  two  ounces  of  a  so- 
lution of  tartar  in  water,  or  as  much  as  is 
requisite  for  completing  the  precipitation. 
The  precipitate  is  then  to  be  edulcorated 
and  filtered ;  and  when  it  is  almost  dry, 
the  above  mentioned  solution  of  indigo  is 
to  be  mixed  with  it.  In  this  maimer  is 
obtained  a  fine  blue  colour,  void  of  all 
acrimony,  which  may  be  mixed  with  wa- 
ter ad  libitum ;  with  which  silk,  leather, 
and  bones  may  be  tinged  of  different 
shades  ;  and  which  with  some  gum  forms 
also  a  fine  sap  colour. 

SAP-GREEN".  See  Colour-making. 
SASSAFRAS  OIL.    See  Oil. 
SAUNDERS'  RED.    See  Dyeing. 
SCARLET  BERRIES,  or  Kermes. — A 
drug  used  in  dyeing.    See  Dyeing. 
SCARLET  COLOUR.    See  Dyeing. 
SCORIA.— The  dross,  or  imperfectly 
vitrified  and  porous  substance,  that  swims 
on  the  surface  of  a  metallic  mixture,  or 
ore,  in  the  furnace  where  metals  are 
smelted  or  refined. 

SCORIFIC  ATION— The  reducing  of  a 
metal  to  scoriae,  in  order  to  separate  it 
from  some  other  metal  less  susceptible  of 
being  thus  acted  on  by  the  fire. 

SCOTT'S  STILL.  See  Distilling 
Apparatus. 

SCREW  CUTTER.  See  Mechanics. 
SCREW  PRESS.    See  Mechanics. 
SCREW  ENGINE,  of  Archimedes.  See 
Engine. 

SCREW,  Power  of  the.  See  Mecha- 
nics. 

SEA  WATER— The  composition,  and 
the  means  of  obtaining  salt  by  the  evapo- 
ration of  sea  water,  has  been  mentioned 
in  the  article  on  salt.  See  also  Water. 
Several  methods  have  been  recommended 
to  render  sea  water  fit  for  drink,  but  none 
answers  the  purpose  except  distillation. 
For  this  end,  various  economical  plans 
have  been  used.  See  Linn  on  Hot  Cli- 
mates, and  Cutbush's  Observations  on  the 
Means  of  Preserving  the  Health  of  Sol- 
diers and  Sailors, 


SEA  SALT.  See  Salt. 
SEA  WAX.  SeeBiTUMr.N. 
SEALING-WAX,  is  a  composition  of 
gum-lac,  melted  and  incorporated  with 
resins,  and  afterwards  coloured  with  sonrn 
pigment,  such  as  vermilion,  verditer, 
ivory  black,  &c. 

There  are  two  kinds  of  sealing  wax  ge- 
nerally used  ;  the  one  is  hard,  for  the  scal- 
ing of  letters,  and  similar  purposes ;  the 
other  soft,  for  receiving  the  impressions 
of  seals  of  office  to  charters,  patents,  and 
other  written  documents. 
'  In  order  to  prepare  the  best  hard  red 
sealing-wax,  take  two  parts  of  shell-lac, 
with  one  of  resin,  and  one  of  vermilion ; 
let  these  ingredients  be  reduced  to  a  fine 
powder ;  melt  them  over  a  moderate  fire, 
and,  when  they  are  thoroughly  incorpo- 
rated, form  the  composition  into  sticks. 
Seed-lac  may  be  substituted  for  shell-lac, 
and  instead  of  resin,  boiled  Venice  tur- 
pentine may  be  employed.  A  coarser 
kind  of  such  sealing-wax  may  be  manu- 
factured by  mixing  equal  parts  of  resin, 
and  of  shell-lac  (or  vermilion  and  red 
lead,  in  the  proportion  of  one  part  of  the 
former  to  two  of  the  latter),  then  proceed- 
ing in  the  manner  above  directed.  But, 
where  large  quantities  of  this  wax  are 
consumed  both  the  vermilion  and  shell-lac 
are  generally  omitted,  so  that  it  may  be 
obtained  at  a  much  cheaper  rate. 

Black  sealing-wax  is  composed  of  gum- 
lac,  or  shell-lac,  melted  with  one-half  or 
one-third  of  its  weight  of  levigated  ivory 
black.  To  prevent  the  composition  from 
becoming  too  brittle,  Venice  turpentine, 
in  the  proportion  of  two-thirds  of  the 
above  ingredients,  is  usually  added ;  as  it 
likewise  contributes  to  improve  the  beau- 
ty of  the  manufacture.  These  substances 
being  melted,  and  properly  stirred  over  a 
slow  fire,  the  liquid  is  next  poured  upon 
an  iron  plate,  or  stone,  previously  oiled, 
and,  while  soft,  it  must  be  rolled  into 
sticks ;  which  are  then  exposed  to  heat, 
till  they  acquire  a  glossy  surface. 

Uncoloured  soft  sealing-wax  is  com- 
monly prepared  of  bees-wax,  lib.;  of  tur- 
pentine, 3  oz.;  and  of  olive  oil,  1  oz.s  these 
ingredients  are  carefully  boiled  in  a  pro- 
per vessel  for  some  time;  till  the  com- 
pound become  fit  to  be  formed  into  rolls, 
or  cakes,  for  use.  And,  in  order  to  im- 
part to  it  the  requisite  colour,  one  ounce 
or  more  of  either  of  the  pig'ments  above 
mentioned  may  be  added,  stirring  the 
mass  till  the  whole  be  duly  combined. 

SEBAC1C  ACID,  or  Acid  of  Fat.— Thh 
acid  is  obtained  by  the  distillation  of  fat. 
It  is  not  applied  to  any  use.  It  exists  co- 
piously in  rancid  butter,  lard,  &c,  and  is 
said  to  give  rise  to  that  peculiar  state. 


SHE 


SHE 


Several  methods  have  been  recommended 
to  get  rid  of  it,  by  using-  alkali,  charcoal, 
&c.;  but  none  answering  the  purpose  com- 
pletely. 

SELENITE.    See  Gypsum. 

SEMI-METAL.    See  Metal. 

SHAGREEN.  See  Manufacture 
of  Shagreex. 

SHEEP.  Under  the  article  Animals, 
Domestic,  we  have  given  some  observa- 
tions on  sheep.  The  following  miscella- 
neous remarks,  are  from  the  pen  of  Dr. 
J.  Mease,  whose  extensive  and  accurate 
information,  l  ender  them  very  valuable.  • 

"  In  May  1809,  Mr.  Alexander  Stuart, 
of  Beverly,  Somerset  county,  Eastern 
Shore,  Maryland,  sheared  five  sheep,  the 
•weights  of  whole  fleeces  were  as  follows. 
They  were  the  lambs  of  the  preceding 
year. 

pounds. 

No.  1;  1(U 

2.  .       .  9 

3.  81 

4.  81 

5.  8 

43f 

At  the  sheep  shearing  of  Mr.  Custis,  of 
Arlington,  Virginia,  in  April  1S09,  the 
following  sheep  were  shorn. 

Columbus,  a  uip  lamb,  by  Mr  .William 
Fitzhugh,  of  Ravensworth,  Virginia  ; 
weight  on  hoof  130^  lbs.  weight  of  fleece 
washed,  5  lbs.  5  oz. 

Horn  Took,  a  tup  lamb,  by  Dr.  William  i 
A.  Dangerfield,  of  Notley-Hall,  Maryland,  i 
weight  on  hoof  132  lbs.  weight  of  fleece  s 
unwashed,  8  lbs.  9  ox.  < 
Palafox,  a  tup  lamb,  by  J.  Scott,  Esq.  3 
of  Strawberry  Hill,  Virginia,  weight  on  1 
hoof  163  lbs.  wool,  unwashed,  but  very  < 
cleanly  kept,  5 lbs.  l3oz.  i 
Two  ewes,  by  W.  H.  Foote,  Esq.  of  f 
Hayfield,  Virginia,  weight  of  one  on  hoof,  i 
91^  lbs.  fleece  unwashed,  7  lbs.  3^,  oz.  of  1 
the  other,  on  hoof,  92  lbs.  fleece  unwash-  i 
ed,  6  lbs.  14  oz.  s 
In  page  91,  of  the  Archives  of  Useful  r 
Knowledge,  No.  1,  I  stated  on  the  autho-  t 
rity  of  a  gentleman  who  has  lately  been  v 
at  Mr  Livingston's  that  the  Merino  tup,  u 
Rambouillet,  weighing  at  the  last  shear-  1< 
ing  (1810,)  155  lbs.  "Mr.  Livingston  in- 
forms me,  this  is  a  mistake  ;  he  only 
weighed  145  lbs. ;  it  was  another  ram, 
Clermont,  that  weighed  155  lbs  ,  with  his 
fleece.  Thus,  at  two  years  old,  he  was 
heavier  than  his  sire,  a  first  rate  imported 
Rambouillet  ram.  It  is  to  be  understood, 
also,  that  the  weights  of  Clermont  and 
the  other  two  rams,  in  1809,  were  taken 
after  being  shorn  Another  of  Mr.  Li- 
vingston's stock  rams,  Jason,  a  shearling, 
in  the  presence  of  two  hundred  witnesses, 


i  yielded  the  present  season,  a  fleece  of 
I,  11  lbs.  12  oz.    This,  as  justly  remarked 
-  by  Mr.  Livingston,  "is  extremely  satisfac- 
tory, since  it  shows  we  have  already 
brought  in  this  country,  the  Merino  sheep 
to  as  great  perfection,  as  they  have  at  - 
s   tained  in  Britain.    Mr.  Toilet's  heaviest 
ram's  fleece  being  exactly  the  same  with 
,  mine." 

The  average  weight  of  the  ewes'  flee- 
■  ces  of  Mr  Livingston's  flock,  is  from  4  to 
.   5  lbs. ;  this  however  referred  to  the  half 
!  and  three-quarter  bloods  ;  the  average  of 
twenty-seven,  bred  ewes,  and  of  seven  full 
i  bred  ewes,  which  was  5  lbs.  2oz.  was 
overlooked.    Mr.  Livingston,  says,  the 
lightest  ewe  fleece  weighing  3  lbs.  7oz. 
and  the  heaviest  8  lbs.  12  oz.    The  aver- 
age of  fleeces,  of  his  full  bred  ewes,  lambs 
included,  was  5  lbs.  13  oz..  that  of  all  his 
ewes,  to  the  number  of  more  than  two 
hundred,  half  bred  included,  was  upwards 
of  5ibs.  2oz.;  a  weight  which  he  consi- 
ders, and  very  justly,  as  a  noble  yield, 
and  very  encouraging  to  those,  who  seek 
for  quantity  as  well  as  quality  of  wool,  and 
especially  when  it  is  considered,  that  nine- 
tenths  of  the  ewes  had  lambs. 
Mr.  Livingston  adds, 
"  Having  given  the  general  average  of 
my  ewe  flocks,  permit  me  now  to  present 
you  with  a  view  of  some  selected  ones,  not 
kept  up  to  be  shorn,  but  running  with  my 
flock,  and  having  lambs  at  their  sides. 
The  greatest  number  you  have  exhibited, 
from  one  flock,  is  eight  long  woolled  ewes 
from  Col.  Tayloe.    These  are  indeed  fine 
sheep ;  but  still  inferior  even  in  quantity 
of  wool,  to  the  same  number  of  Clermont 
Merinos.    Eight  of  his  ewes  62^  lbs.  of 
wool.  All  mine  were  weighed,  and  book- 
ed in  the  presence  of  two  hundred  wit- 
nesses ;  the  wool  in  the  yoke,  but  free- 
from  tags,  and  the  sheep  as  clean,  as  it 
was  possible  for  unwashed  Merinos  to  be, 
having  been  littered  all  winter,  and  kept 
in  clean  grass  grounds,  at  all  other  times, 
and  having  been  washed  by  the  heavy 
rains,  which  fell  every  day  for  a  fortnight 
together,  till  five  or  six  days  before  they 
were  shorn.  The  weights  of  eight  of  mine 
under  these  circumstances  were  as  fol- 
lows : 


lbs. 

oz. 

1.  weighed 

8 

12 

2.  — 

8 

6 

3.   

8 

4 

4.  

8 

8 

6.   

7 

14 

7.   

7 

14 

8.   

7 

12 

61 

14 

Average  8  lbs.  1  oz.  15  dwt. 


SHE 


SHE 


The  average  of  twenty-four,  selected 
from  Col.  Tayloe's  flock,  was  a  little  bet- 
ter than  5  lbs.    The  average  of  all  my 
full  bred  ewes  taken  collectively,  was 
5  lbs.  13  oz. ;  and  that  of  my  whole  flock, 
of  upwards  of  two  hundred  ewes,  exceed- 
ed by  some  ounces  Col.  Tayloe's  twenty- 
four    The  average  of  half  my  flock,  in- 
cluding the  four  rams,  was  7  lbs.  10  oz. 
this  average  struck  upon  upwards  of  one 
hundred  sheep.  The  average  of  one  third 
of  my  full  bred,  and  seven-eight  bred 
ewes,"  was  7  lbs.  3  oz.  12  dwt    The  aver- 
age upon  one-third  of  my  three-quarter 
ewes  only,  6  lbs.  11  oz,  12  dwt.    It  is  ob- 
vious then,  that  if  1  were  now  to  part  with 
half  my  ewes,  retaining  only  the  best,  that 
my  fleeces  would  be  as  heavy  as  Mr. 
Toilet's  celebrated  flock  of  full  bred  Me- 
rinos ;  and  that  if  I  was  to  cull  out  of  my 
present  number,   seventy   of  the  best 
ewes,  that  their  fleece  would  average 
seven  pounds,  which  considering  the  dif- 
ference in  the  degree  of  cleanliness,  be- 
tween mine  and  the  sheep  at  Rambouillet, 
would  bring  them  very  near  to  a  par : 
for  Mr.  Lasteyrie  says,  they  had  not  yet 
attained  collectively  to  eight  pounds.  And 
yet  the  sheep  of  Rambouillet  are  acknow- 
ledged, to  be  superior  to  any  in  Europe, 
so  mucb  so,  that  Mr.  Delessert  in  a  letter 
of  the  9th  February  last,  mentions  to  me, 
that  prime  rams  from  that  flock,  were  sold 
at  1500  francs,  (300   dollars.)  While 
other  prime  blooded  Spanish  Merinos, 
only  sold  at  from  2  to  300  francs.  Lest 
those  who  have  not  seen  my  sheep,should 
suppose  that  these  heavy  fleeces  are  in- 
ferior to  the  lighter  ones,  of  other  flocks 
in  quality,  I  need  only  observe,  that  the 
Rambouillet  fleeces,  from  which  mine  are 
derived,  are  the  finest  in  Europe.  That 
my  wool  has  sold  constantly  to  manufac- 
turers, at  two  dollars  per  pound  in  the 
yolk,  and  is  purchased  with  great  avidity 
To  you  sir,  who  have  seen  samples  of  it, 
I  need  say  nothing  on  this  subject,  since 
you  are  well  satisfied  of  its  superiority. 
And  in  the  letter  you  did  me  the  favour 
to  write,  July  2d,  1809,  you  say,  that  you 
have  shown  the  specimens  to  the  mem- 
bers of  the  Cattle  Society,  and  that  it  was 
agreed  that  none  of  you,  had  seen  such 
beautiful  samples ;   and  you  add,  "  the 
staple  is  double  the  length  of  Col  Hum- 
phreys' ram,  which  I  had  two  years,  and 
had  a  silkiness  and  wavey  appearance, 
which  the   other  is  entirely  deficient 
in." 

The  following  statement,  will  serve  to 
show  the  quantitity  of  provender,  consum- 
ed by  five  Merino  three-quarter  wethers, 
in  England,  and  their  consequent  increase 


in  weight.  The*  sheep  were  exhibited  at 
the  Cattle  Show  of  Lord  Somerville,  in 
March  last,  in  London  ;  and  had  been 
fed  by  Morris  Birkbeck,  a  well  known  re- 
spectable agriculturalist. 

pounds. 

Weight,  November  30,  1809,  537 
March  2,  1810,       .  670 

Increase,  133 

Cvit.  qrs.  lbs. 

Having  eat,  of  hay,       .        10    3  2 
turnips,  21    1  20 

100  oil  cakes,     2    2  20 

Notice  had  been  taken  by  Mr.  Dupont, 
of  the  remark  made  by  Dr.  Mease,  "  that 
Don  Pedro  has  very  little  wool  on  his 
legs."  The  present  deficiency  in  that  re- 
spect, observable  in  him,  he  ascribes  to 
his  great  age,  and  says,  that  when  young- 
er, he  was  clothed  down  to  the  hoof,  that 
his  progeny  carry  the  same  mark,  and 
that  he  thinks  it  characteristic,  of  true 
thorough  bred  stock.  It  is  a  fact  how- 
ever, that  Mr.  Smith's  ram,  had  but  little 
wool  on  his  legs,  and  yet  that  the  highest 
price  was  offered  for  his  fleece,  by  a  ma- 
nufacturer; and  further,  that  the  progeny 
of  Merinos  of  the  same  cross,  differ  much 
in  the  proportion  of  wool  on  their  legs. 
This  remark  I  have  often  made  when  ex- 
amining my  own  flock,  and  that  of  others. 
It  may  be  well  to  attend  to  the  circum- 
stance, in  order  to  determine,  whether 
there  be  any  absolute  connexion  (in  the 
full  blood,)  between  very  woolly  legs  and 
quality  of  fleece. 

The  following  account,  from  the  Vir- 
ginia Argus,  of  the  utility  of  salving  sheep, 
is  recorded  as  confirmation  of  that  prac  - 
tice  already  recommended. 

Mr.  Pleasants. — I  have  long  thought 
of  communicating  to  the  public,  a  reme- 
dy for  the  cure  of  the  rot,  and  scab  in 
sheep,  which  I  have  made  use  of  with 
very  great  success.  In  the  year  1806,  my 
flock  was  so  very  indifferent,  that  from  90 
sheep,  I  sheared  only  130  weight  of  wool, 
so  sorry  as  to  be  barely  fit  to  make  cloth- 
ing for  young  negroes.  Immediately  af- 
ter shearing,  I  made  use  of  the  following 
mixture  :  Three  gallons  of  tar,  and  three 
gallons  of  train  oil,  boiled  together,  to 
which  were  added,  three  pounds  of  roll 
brimstone,  finely  powdered  and  stirred 
in.  This  quantity  was  sufficient  for  the 
above  number,  and  was  poured  or.  with 
a  kitchen  ladle,  from  the  top  of  the  head 
along  the  back  bone,  to  the  tail 

At  the  next  shearing,  (in  1807,)  from 
1  seventy-eight  of  the  same  sheep,  I  shear- 


SHE 


SHE 


ed  three  hundred  and  sixty  pounds,  of 
very  good  wool,  and  instead  of  twenty  tc 
twenty -five  sorry  lambs,  commonly  raised 
from  my  flock,  I  raised  fifty-five  as  fine  as 
ever  I  saw.  Since  this  application,  1  have 
frequently  been  asked  by  my  neighbours, 
where  I  got  such  fine  sheep.  This  re- 
medy was  taken  from  an  old  eastern  pa- 
per, which  I  am  sorry  to  say,  I  have  lost 
or  mislaid.  It  may  be  necessary  to  add, 
that  I  have  continued  to  make  use  of  this 
application  with  the  same  success,  and 
that  when  train  oil  is  difficult  to  be  had, 
any  kind  of  grease,  such  as  is  used  for 
plantation  leather,  will  answer.  1  am  Sir, 
your  obedient  servant, 

J.  NELSON." 
Mecklenburg,  June  13,  1808. 

In  order  to  judge  of  the  comparative 
profit  of  feeding  two  breeds  of  sheep, 
says  the  Doctor,  the  following  statement 
of  the  weights  of  seven  sheep,  of  the  Irish 
breed  is  given.    They  were  raised  and 

fed  by  Francis  Hickman,  of  Chester  coun-  J  lambs,  about  7  lbs.  14  oz. 


lbs. 

oz. 

A  ram,  Judas, 

12 

4 

A  ram,  Don  Carlos, 

9 

12 

An  imported  ewe, 

7 

Ditto 

7 

8 

Ditto 

7 

s 

Ditto 

10 

4 

Ditto 

8 

4 

Ditto 

8 

Ditto 

6 

12 

Ditto 

6 

4 

A  ewe  lamb,  Sancho,  15  months 

old,  ..... 

9 

A  ram,  Palafox,       .       .  , 

8 

8 

A  ewe  lamb,  .... 

7 

8 

A  young  ram,  Columbus,  ten 

months  old, 

7 

A  young  ram, 

5 

A  voung  ewe,  about  ten  months 

old, 

5 

4 

125 

12 

Averaging  the   flock,  including  the 


ty,  Pennsylvania,  and  killed  in  March 
1812,  by  Joseph  Grofle,  of  Spring  Gar 
den. 


Skin. 

Fat. 

MeaL 

pounds. 

pounds. 

pounds 

1. 

15 

'26* 

115 

o. 

20 

25~ 

149 

3. 

m 

23^ 

133 

4. 

154 

34^ 

139 

5. 

19 

22 

105 

6. 

m 

2U 

120 

7. 

16 

27 

115 

The  precise  cost  of  feeding  the  above 
sheep,  cannot  at  present  be  ascertained. 
Indian  corn,  oats,  and  hay,  were  however 
given  in  abundance,  besides  pasture 
two  or  three  years.  If  the  facts  can  be 
procured,  they  shall  be  given  hereafter. 

On  the  stall  they  appeared  covered  with 
fat ;  so  fat  indeed,  that  it  was  difficult  to 
find  any  flesh,  and  no  greater  proof  could 
be  required,  of  the  absurdity  of  a  system 
of  cramming,  requisite  to  produce  such 
over  ripe  animals.  One  leg  weighed  19 
pounds ! 

Weights  of  Merino  Fleeces. 

George-town,  Kentucky,  April  29,1812. 
On  Tuesday  last,Williaro  Story  of  George- 
town, sheared,  of  the  flock  belonging  to 
Story  and  Nichols,  sixteen  full-blooded 
Merino  sheep  ;  ten  of  which  were  import- 
ed from  Spain.    The  product  was  as  fol- 


Tlie  above  shearing  was  attended  by 
about  100  persons. 

It  is  not  stated  whether  the  above  sheep 
had  been  washed  previously  to  shearing. 
If  they  had  not,  some  allowance  must  be 
made,  for  loss  in  weight ;  even  with  that 
deduction,  their  weights  were  respecta- 
ble. 

Merinos  yield  7^,  8,  8^  and  9  lbs.  wool; 
the  animals  having  been  previously  wash- 
ed. 

The  following  additional  remarks  are 
taken  from  Dr.  Parry's  essay  on  the  meri- 
no sheep,  in  his  communications,  to  the 
board  of  agriculture,  England,  and  may 
be  found  useful  to  our  farmers, 
j  The  merinos  in  Spain  are  about  five 
for  i  million,  which  are  divided  into  Trasha- 
mantes  and  Estantes,  indicative  of  the  dif- 
ference in  their  species.  The  heads  of 
these  animals  are  large,  and  their  necks 
long.  Their  chests  are  contracted,  and 
are  sharp  on  the  shoulders  and  flat  sided. 
As  they  are  narrow  across  the  loins,  their 
hind  quarters  are  straight  and  defective. 
The  skins  of  the  merino  are  remarkably 
thin,  soft,  and  loose,  affording  that  evi- 
dence of  a  strong  disposition  to  fatten, 
which  many  of  the  farmers  call  proof. 
The  skin  in  many  other  respects  differs 
from  common  sheep.  These  animals 
seem  absolutely  humid  in  wool.  It  exists 
in  their  foreheads  almost  as  low  as  the 
eyes,  and  on  their  cheeks ;  covers  their 
bellies,  and  envelopes  their  hind  legs,  and 
sometimes  their  fore  legs,  down  to  then- 
very  hoofs.   The  length  of  the  filaments 


SHE 


SHE 


is  from  two  to  three  inches  ;  but  the  wool 
of  the  ram  is  the  coarsest  and  longest ; 
that  of  the  ewe  finest  and  shortest ;  and 
that  of  the  wether,  in  both  respects,  be- 
tween the  former.  They  give,  upon  an 
average,  about  5  lbs.  of  wool.  Of  the 
rams'. fleeces  in  Spain,  it  is  probable  that 
the  medium  weight  does  not  exceed  7  lbs. 
The  flocks  belonging  to  the  monks,  in 
Spain,  produce  a  great  variety,  as  to  size, 
8cc.  According  to  a  Spanish  shepherd, 
when  the  fleeces  undergo  the  operation  of 
washing  for  sale,  which  is  never  perform- 
ed on  the  sheep's  back,  but  always  after 
the  wool  is  sorted,  they  lose  three-fifths  of 
their  weight;  this,  however,  is  ruinous. 
"When  afterwards  scoured  by  the  clothier, 
a  further  loss  is  sustained  of  about  three, 
or  three  and  a  half,  in  twenty,  which 
amounts  to  somewhat  less  than  one-third 
of  the  original  weight  of  the  wool  in  the 
full  yolk.  The  average  reduction  of  the 
merino  wool  to  perfect  cleanness  is  about 
two-thirds  of  the  original  weight  of  the 
unwashed  fleece.  The  wool  of  the  meri- 
no differs  from  all  other  breeds  in  being 
of  nearly  an  equal  degree  of  fineness  on 
the  shoulder  and  on  the  rump.  There 
are  a  variety  of  circumstances,  which 
render  the  merino  different  from  other 
sheep,  as  is  shewn  by  M.  Pictet,  of  Ge- 
neva. 

Fifteen  sheep  per  day  to  shear  is  con- 
sidered in  Spain  one  day's  work  for  a 
man.  Powdered  charcoal  is  dropped  on 
any  wound  of  the  flesh  of  the  merinos, 
and  is  said  to  heal  it  in  a  short  time.  Af- 
ter shearing,  an  ochrous  earth  is  used  on 
the  back  of  the  animal,  in  Spain,  in  order 
to  prevent  the  access  of  ail.  The  lambs 
are  shorn  without  being  previously- 
sweated. 

With  respect  to  the  different  kinds  of 
wool,  see  Manufacture  of  Cloth. 

On  the  liambouillet  flock,  it  is  observ- 
ed, whether  housed  or  folded,  they  are 
not  permitted  to  go  out  to  feed  till  the 
dew  is  dissipated  ;  and  to  this  precaution 
is  c  uetiy  attributed  their  exemption  from 
the  rot.  With  the  same  view,  in  moist 
weather,  their  hunger  is  first  appeased 
with  dry  food.  From  30  to  40  ewes  are 
allotted  to  each  ram  :  both  sexes  should 
be  at  least  two  years  old ;  but  we  are 
told,  that,  if  persons  are  eager  to  aug- 
ment their  flocks,  the  txvo-tooths  may  be 
allowed  to  take  the  ram  without  injury, 
provided  the  lambs  are  made  to  suck 
other  dams,  or  she  goats  ;  it  having  been 
found  that  it  is  nursing,  rather  than  gesta- 
tion, which  impedes  their  growth,  and 
lessens  their  fleece.  The  wool  of  the  4th 
cross  of  the  merino  ram  with  the  com- 

YOL.  II. 


mon  ewes,  is  usually  equal  to  that  of  the 
pure  race. 

There  are  several  publications  on  the 
subject  of  merino  sheep,  both  in  this  coun- 
try and  in  Europe,  which  we  refer  to. 

SHEEP-FOLD.— The  society  for  the 
improvement  of  arts  awarded  the  gold 
medal  to  Mr.  Plowman,  for  an  improved 
sheep-fold.  The  following  description  we 
take  from  the  transactions  of  the  society. 
The  model  of  Mr.  Plowman's  fold  was 
forwarded  to  the  secretary  of  the  society, 
with  a  letter  describing  its  properties  and 
construction.  This  fold  may  be  also  used 
for  swine,  with  considerable  advantage. 
Where  hogs  are  folded  in  the  usual  man- 
ner, great  difficulties  are  experienced  for 
want  of  stowage,  for  them  to  feed  off 
winter  tares,  &c.  as  they  root  up  every 
stake  or  hurdle.  Mr.  Plowman,  howe- 
ver, is  certain  that  his  fold  will  keep  them 
in,  and  defy  their  attempts  to  displace  it. 

With  respect  to  sheep,  one  man,  he 
observes,  can  remove  a  fold  to  contain 
three  huudred  with  ease  in  five  minutes, 
which,  by  the  old  method,  frequently 
takes  some  hours  to  accomplish.  A  num- 
ber of  gentlemen  who  have  used  these 
folds  in  Europe,  among  whom  is  the  duke 
of  Bedford,  have  given  their  approbation 
of  them.  The  fold  is  made  on  an  improv- 
ed and  very  simple  principle,  combining 
many  advantages  over  the  old  and  ex- 
pensive method  of  folding  by  hurdles ; 
and  as  the  whole  fold  can  be  removed 
with  ease  at  all  times,  it  is  found  pecu- 
liarly useful  in  feeding  off  turnips  on  the 
land  in  frosty  weather,  when  hurdles  can- 
not be  used ;  and,  as  the  saving  of  labour 
in  agriculture  is  a  leading  object,  he  has 
no  doubt  of  seeing  it,  in  a  very  few  years, 
generally  adopted. 

The  expense,  in  the  first  instance,  will 
exceed  that  of  hurdles,  for  the  same  giv- 
en quantity  of  sheep  ;  but  having  had  one 
in  use  nearly  three  years,  he  is  satisfied 
the  saving  will  be  very  considerable  :  for, 
before  he  adopted  this  method  of  fold- 
ing, he  lost  from  thirty  to  forty  nights 
folding  in  the  year,  owing  to  the  land  be- 
ing* hard  in  dry  seasons,  such  as  the  two 
last;  which  renders  folding  almost  im- 
practicable, as  they  never  can  be  set  with- 
out great  labour  and  destruction  of  hur- 
dles. He  is  also  clearly  of  opinion,  that 
the  stock  of  sheep  will  be  greatly  in- 
creased when  this  method  of  folding  be- 
comes more  known  ;  and  that  it  will  ena- 
ble many  small  farmers  to  keep  from  fifty 
to  one  hundred  sheep,  who  now  are  de- 
terred from  it,  on  account  of  the  small 
quantity  of  feed  they  have,  not  answering 
to  keep  a  man  for  that  purpose  only ;  but 
7  Z 


SHE 


SIIO 


by  this  plan,  they  may  keep  a  boy  at  three 
shillings  or  three  shillings  and  sixpence 
per  week,  who  can  attend  on  one  or  two 
hundred  sheep,  and  move  the  fold  him- 
self without  any  assistance.  In  heavy 
gales  of  wind  it  frequently  happens  that 
hurdles  are  blown  down,  and  the  sheep, 
of  course,  being  at  liberty  to  range  over 
the  crops,  do  incalculable  mischief; 
which  cannot  happen  with  this  fold. 

When  the  fold  is  wanted  to  be  used  on 
very  hilly  ground,  it  is  best  to  begin  at 
the  top,  and  work  it  down  to  the  bottom, 
for  the  ease  of  removing  it,  and  then 
draw  it  up  again  with  a  horse.  This, 
however,  the  inventor  has  never  had  oc- 
casion to  do;  for  the  laud  in  his  country 
is  ploughed  in  a  contrary  direction,  and 
the  fold  is  worked  in  the  same  course  as 
the  ridges.  By  this  means,  the  inconve- 
nience is  avoided  of  crossing  the  furrows, 
and  they  are  also  a  guide  to  keep  the  fold 
in  a  straight  direction. 

With  respoct  to  the  sheep  getting  un- 
der, he  does  not  recollect  that  circum- 
stance to  have  ever  happened,  nor  does 
he  conceive  that  any  land,  which  is  culti- 
vated, can  be  so  uneven  as  to  admit  of  it. 

Description  of  the  Sheepfold. 

Plate  XII!.  fig  1.  Shows  one  division 
or  part  of  this  fence  twenty -one  feet  long, 
and  three  feet  eleven  inches  high,  com- 
posed of  the  following  parts  : 

A.  A  top  rail  three  inches  deep  and 
two  inches  thick  B.  The  upper  bar, 
three  inches  deep,  and  three-quarters 
inch  thick.  C  C,  the  two  lower  bars,  four 
inches  by  three-quarters  of  an  inch,  which, 
with  the  upper  bar,  are  morticed  through 
the  uprights.  DDDD,  which  uprights 
are  oak,  three  inches  by  two  inches.  E, 
the  lower  bar,  three  inches  by  three.  F, 
an  upright  bar,  with  the  horizontal  bars 
halved  into  it.  GG,  two  oak  uprights, 
three  by  two  inches. 

Fig.  "2-  Shows  the  oak  uprights  G  G. 
H,  the  axle-tree,  three  inches  by  three, 
and  three  feet  between  the  wheels.  I,  an 
oak  knee,  which  connects  the  uprights 
G  G  with  the  axle-tree,  by  means  of  two 
screws  and  nuts. 

Fig.  3.  A  plan,  in  which  the  axle  H  is 
shown  with  two  arms  K  K  at  right  angles 
to  H,  which  are  made  to  act  as  pivots  to 
the  wheels,  when  intended  to  be  moved 
in  a  direction  at  right  angles  to  the  bars. 

Fig.  4  Is  a  view  of  the  same  parts  de- 
scribed in  fig.  5.  The  wheels  marked  W, 
in  all  the  figures,  are  of  cast  iron,  and 
cost  three  shillings  and  sixpence  each. 

SIIEEVE.    See  Mechanics. 

SHELLS. — Marine  shells  may  be  divid- 
ed, as  Mr.  Hatchett  observes,  into  two 


kinds :  Those  that  have  a  porcellaneous 
aspect,  with  an  enamelled  surface,  and 
when  broken  are  often  in  a  slight  degree 
of  a  fibrous  texture  ;  and  those  that  have 
generally,  it  not  always,  a  strong  epider- 
mis, under  which  is  the  shell,  principally 
or  entirely  composed  of  the  substance 
called  nacre,  or  mother-of-pearl. 

The  porcellaneous  shells  appear  to 
consist  of  cavbonat  of  lime,  cemented  by 
a  very  small  portion  of  animal  gluten- 
This  animal  gluten  is  more  abundant  in 
some,  however,  as  in  the  patellae, 

The  mother-of-pearl  shells  are  compos- 
ed of  the  same  substances.  They  differ, 
however,  in  their  structure,  which  is  la- 
mellar, the  gluten  forming  their  mem- 
branes, regularly  alternating  with  strata 
of  carbonat  of  lime.  In  these  two  the 
gluten  is  much  mo.-e  abundant. 

Mr.  Hatchett  made  a  few  experiments 
on  land  shells  also,  which  did  not  exhibit 
any  differences.  But  the  shells  of  the 
crustaceous  animals  he  found  to  contain 
more  or  less  phosphat  of  lime,  though  not 
equal  in  quantity  to  the  carbonat,  and 
hence  approaching  to  the  nature  of  bone. 
Linnaeus,  therefore,  he  observes,  was 
right,  in  considering  the  covering  of  the 
echini  as  crustaceous,  for  it  contains  phos- 
phat of  lime.  In  the  covering  of  some  of 
the  species  of  asterias,  too,  a  little  phos- 
phat of  lime  occurs ;  but  in  that  of  others 
there  is  none — Phil.  Trans. 
SHELL  LIME.  See  Lime. 
SHELL  MARL.  See  Maul,  and  Agri- 
culture. 

SHOES,  hoiv  made  water-tight.  See 
Water-Proof. 

SHOE,  in  Farriery.    See  Farriery. 
SHOT,  Patent. — The  manutacture 
of  shot  has  been  heretofore  mentioned. 

Shot  manufactories  have  lately  been 
established  or  revived,  and  appear  to  pro- 
mise to  supersede  the  importation  of  En- 
glish shot.  They  are  manufactured  prin- 
cipally from  lead  found  in  Louisiana,  and 
shipped  from  New-Orleans 

Patent  shot,  as  Dr.  Black  has  informed 
us,  are  manufactured  in  England  as  fol- 
lows : 

A  little  orpiment  or  arsenic  is  added  to 
the  lead,  which  disposes  it  to  run  into 
spherical  drops  much  more  rapidly  than 
it  would  do  when  pure.  The  melted  lead 
is  poured  into  a  cylinder,  whose  circum- 
ference is  pierced  with  holes.  The  lead 
streaming  through  the  holes  soon  divides 
into  drops,  whicn  fall  into  water,  where 
they  congeal.  They  are  far  rom  be- 
ing all  spherical,  many  being  shaped 
like  pears,  and  must  be  picked.  This  is 
done  by  a  very  ingenious  contrivance. 
The  whole  is  sifted  on  the  upper  end  of  a 


SIL 


SIL 


long,  smooth,  inclined  plane,  and  the 
grains  roll  down  to  the  lower  end.  But 
the  pear-like  shape  of  the  bad  grains 
makes  ihem  roll  down  irregularly,  and 
thev  waddle  as  it  were  to  a  side ;  while 
the  round  ones  run  straight  down.  They 
are  received  into  a  sort  of  funnel,  which 
extends  from  the  one  side  of  the  inclined 
plane  to  the  other,  and  is  divided  by  seve- 
ral partitions,  so  that  it  is  really  the 
mouth  of  several  funnels,  which  lead  to 
different  boxes.  Those  in  the  middle  re- 
ceive the  round  grains.    See  Lead. 

SHU. VI AC,  or  Sumach. — The  leaves  of 
this  plant  are  used  in  abundance  in  seve- 
ral of  the  manufactures  of  our  country. 

It  is  largely  used  in  dyeing  in  lieu  of 
galls,  as  it  contains  a  considerable  quan- 
tity of  gallic  acid,  in  making  black  mo- 
rocco, and  in  ink  making.  It  is  hardly 
necessary  to  remark,  that  it  is  used  in  the 
same  manner,  and  for  the  same  purpose, 
as  »•  ills  ;  with  copperas  or  sulphatof  iron, 
it  forms  a  black  colour.  As  galls  are 
scarce,  other  vegetable  astringents  are 
necess^P.  Hence,  also,  its  use  in  the 
manufacture  of  ink  powder.  Very  good 
Writing  ink  may  be  made  by  using  one  or 
two  ounces  of  shumac,  half  an  ounce  of 
gum  arabic  or  Senegal,  and  one  pint  of 
water;  or  a  mixture  of  equal  parts  of 
shumac  and  galls,  and  the  other  articles 
in  the  same  proportion  may  be  used.  Pig 
nut  is  also  a  substitute  for  galls ;  but 
shumac  is  considered  superior.  Shumac 
grows  abundantly  in  the  United  States. 
See  Sumach. 

SILK,  is  a  fibre  or  thread  spun  by  the 
silk-worm,  to  form  a  nidus  for  its  preser- 
vation in  the  chrysalis  state.  It  is  wound 
off  in  the  manufactories,  and  afterward 
joined  or  spun  into  thicker  threads.  We 
do  not  possess  any  explanation  of  the  pro- 
cess, by  which  silk,  which  in  the  body  of 
the  insect  has  the  form  of  a  glutinous  un- 
organized mass,  becomes  consistent, 
firm,  and  very  strong,  in  an  exceeding 
short  time  after  it  has  been  drawn  out  in- 
to  thread.  Anglers  have  a  practice  of 
cutting  the  body  of  a  silk-worm,  and 
drawing  out  the  whole  of  the  silky  con- 
tents into  a  string  of  a  few  inches  long, 
which  speedily  acquires  consistence,  has 
the  appearance  of  catgut  or  fiddle-string, 
but  is  more  transparent,  and  is  on  that  ac- 
count less  visible  under  water  when  used 
as  a  fishing-line.  Chappe  lias  made  very 
interesting  researches  as  to  the  manage- 
ment of  this  matter.  He  dissects  the  ves- 
sels out  of  the  silk-worm,  washes  them 
with  water,  and  then  dilutes  their  con- 
tents by  trituration  with  about  one  third 
of  its  Weight  of  water.  By  this  prepara- 
tion they  could  be  blown  into  permanent 


globes,  and  otherwise  formed.  Sec  -2/  - 
nales  de  Chimii ,  xi.  11.3. 

Silk  appears  to  be  a  sort  of  dried  gum- 
my matter.  It  differs  from  vegetable  sub- 
stances, 1.  in  affording  ammonia  by  dis- 
tillation :  2.  in  affording  nitrogen  gas  by 
treatment  with  nitric  acid  :  3.  in  affording 
a  peculiar  oil,  which  is  separated  from  it 
when  the  nitric  acid  converts  it  into  oxalic 
acid,  as  has  been  shown  by  Berthollet.  It 
seems  to  be  a  compound,  consisting  of  a 
vegetable  mucilage,  with  a  peculiar  ani- 
mal oil,  which  renders  it  pliant,  ductile, 
and  elastic. 

Silk  is  naturally  coated  with  a  sub- 
stance, which  has  been  considered  as  a 
gum,  to  which  it  owes  its  stiffness  and 
elasticity :  that  which  is  most  commonly 
met  with  in  France  contains,  besides,  a 
yellow  colouring  matter. 

Most  of  the  purposes  for  which  silk  is 
employed,  require  that  it  should  be  de- 
prived not  only  of  its  colouring  matter, 
but  also  of  its  gum.  Both  these  pur- 
poses are  answered  by  means  of  soap, 
and  the  term  scouring  is  applied  to 
this  operation,  by  which  it  acquires  its 
suppleness  and  whiteness.  The  scouring 
ought  not  to  be  so  complete  for  silks 
which  are  to  be  dyed,  as  for  those  which 
are  intended  to  remain  white ;  and  a  dif- 
ference ought  even  to  be  made,  according 
to  the  colour  we  mean  the  silk  should 
have. 

This  difference  consists  chiefly  in  the 
quantity  of  soap  employed:  thus,  for 
common  colours,  it  is  generally  thought 
sufficient  to  boil  the  silk  for  three  or  four 
hours  in  a  solution  of  twenty  pounds  of 
soap  for  each  hundred  of  silk,  taking  care 
to  fill  up  the  kettle  with  water  from  time 
to  time,  that  there  may  be  always  a  suffi- 
cient proportion  of  fluid.  The  quantity 
of  soap  is  increased  for  those  silks  which 
are  to  be  dyed  blue,  and  more  especially 
for  those  that  are  to  be  scarlet,  cherry- 
colour,  &c. ;  because  for  these  colours 
the  ground  must  be  whiter  than  for  such 
as  are  less  delicate.  In  treating  of  each 
colour,  the  quantity  of  soap  proper  for 
the  silk  intended  to  receive  it,  is  mention- 
ed. 

When  silk  is  to  be  employed  white,  it 
undergoes  three  operations.  The  first  is 
called  by  the  French  degommage,  and 
by  our  workmen  shaking  over  ;  it  con- 
sists in  keeping  the  hanks  of  silk  in  a  so- 
lution of  thirty  pounds  of  soap  to  a  hun- 
dred of  silk :  this  solution  ought  to  be  ve- 
ry hot,  but  not  boiling :  when  that  part  of 
the  hank  which  is  immersed  is  entirely 
freed  from  its  gum,  which  is  known  by 
the  whiteness  it  acquires,  the  hanks  are 
turned  upon  the  skein -sticks,  so  that  the 


SIL 


SIL 


part  which  was  not  before  immersed  may 
undergo  the  same  operation  ;  they  arc 
then  taken  out  of  the  kettle  and  wrung 
out,  according  as  the  operation  is  com- 
pleted. 

The  second  operation  is  the  cuite  or 
boiling-.  The  silk  is  put  into  bags  of 
coarse  cloth,  five-and-twenty  or  thirty 
pounds  in  each  bag,  which  is  called  a 
boiling  bag  (poche)  ;  a  bath  of  soap  is 
prepared  like  the  former,  but  with  a  less 
quantity  of  soap;  in  this  the  bags  are 
boiled  for  an  hour  and  a  half,  taking  care 
to  keep  them  constantly  stirred,  that  those 
which  touch  the  bottom  of  the  kettle  may 
not  receive  too  much  heat. 

The  third  operation  is  called  bleaching, 
or  whitening,  which  is  principally  intend- 
ed to  give  the  silk  a  slight  cast,  to  make 
the  white  more  pleasing ;  and  from  which 
it  derives  different  names,  such  as  china 
white,  silver  white,  azure  white,  or  thread 
white.  A  solution  of  soap  is  prepared, 
the  proper  strength  for  which  is  deter- 
mined by  its  mode  of  frothing  when  agi- 
tated :  for  the  china  white,  which  should 
have  a  slight  tinge  of  red,  a  small  quanti- 
ty of  annotta  is  added,  and  the  silk  is 
shaken  over  in  it,  until  it  has  acquired 
the  desired  shade.  To  the  other  whites, 
more  or  less  of  a  blue  tinge  is  given  by 
adding  a  little  blue  to  the  solution  of  soap, 
though  some  had  before  been  put  into  the 
boiling. 

To  prepare  the  azure,  fine  indigo  is  ta- 
ken ;  and  after  being  well  washed  two  or 
three  times  in  moderately  warm  water,  it 
is  ground  fine  in  a  mortar,  and  boiling  wa- 
ter poured  on  it:  it  is  then  left  to  settle, 
and  the  liquor  alone  is  employed,  which 
retains  only  the  most  subtile  parts :  this 
is  called  azure  A  small  quantity  of  the 
liquor  of  a  fresh  vat  of  indigo  may  be 
substituted  for  azure. 

At  Lyons,  where  they  make  a  more 
beautiful  white  than  at  Paris,  no  soap  is 
used  in  the  third  operation  ;  but  after  the 
second,  the  silks  are  washed,  fumigated 
with  sulphur,  and  azured  with  river  wa- 
ter In  this  method  it  is  of  importance  to 
employ  very  clear  water. 

When  the  silk  has  become  very  uni- 
form, and  has  acquired  the  desired  shade, 
it  is  wrung  out  and  dried. 

The  white  obtained  by  these  means  is 
not  yet  sufficiently  bright  for  the  silk  in- 
tended for  white  stuffs ;  but  must  still 
be  exposed  to  the  vapour  of  sulphur. 

As  soap  seems  to  impair  the  lustre  of 
silk,  the  academy  of  Lyons,  in  1761,  pro- 
posed as  the  subject  of  a  prize  disserta- 
tion, to  find  a  method  of  scouring  silks 
without  soap  ;  and  the  prize  was  adjudg- 
ed to  Mr.  Rigautj  of  S.  Quenlin,  who  pro- 


posed substituting  for  soap  a  solution  of 
soda,  or  carbonat  of  soda,  so  much  dilut- 
ed with  water  as  not  to  injure  the  silk  ; 
but  some  inconvenience  must  have  attend- 
ed the  practice  of  this  method,  as  it  is 
not  adopted,  though  generally  known, 
and  easy  of  execution. 

The  Abbe  Collomb  has  published  some 
observations  highly  worthy  of  attention, 
respecting  the  scouring  of  silk  by  the  ac- 
tion of  water  alone.  Having  perceived, 
that  a  skein  of  yellow  silk,  which  he  had 
boiled  for  about  three  hours  in  common 
water,  had  lost  nearly  one  eighth  of  its 
weight,  he  repeated  the  boiling  twice, 
and  thereby  brought  the  diminution  to 
nearly  one  quarter. 

The  silk  which  has  suffered  this  loss  of 
weight  still  retains  a  yellow  or  rather 
chamois  colour,  which  renders  it  unfit  for 
white  stuffs,  or  for  such  as  are  intended 
to  receive  any  colour  the  beauty  of  which 
depends  on  the  whiteness  of  the  ground 
upon  which  it  is  applied :  but  it  takes 
those  colours  very  well,  which  cannot  be 
injured  by  the  tinge  it  retains;  "us  the 
black  which  it.  took  seemed  preferable  to 
that  of  silk  scoured  with  soap. 

The  silk  remains  very  firm  and  strong 
after  this  operation ;  the  threads  of  it, 
compared  with  similar  ones  scoured  with 
soap,  supported  weights  which  broke  the 
others. 

Eight  hours  of  brisk  ebullition  are  re- 
quired to  dissolve  the  whole  gummy  coat 
of  silk,  and  it  thereby  loses  a  little  more 
than  one  fourth  of  its  weight ;  but  the 
boiling  ought  to  be  continued  longer 
when  the  barometer  is  low,  because  the 
greater  the  weight  of  the  atmosphere,  the 
higher  is  the  degree  of  heat  at  which  wa- 
ter boils. 

This  consideration  led  Mr.  Collomb  to 
try  the  effect  of  boiling  silk  in  Papin's  di- 
gester; and  he  found,  that  only  one  hour 
and  a  quarter  were  required  to  complete 
the  solution  of  the  gummy  coat,  although 
the  degree  of  heat  must  have  been  infe? 
rior  to  that  which  produced  many  of  those 
effects  observed  by  philosophers  iu  that 
concentrated  kind  of  ebullition. 

Berthollet  says,  that  he  saw  a  pattern 
of  silk  stuff*  scoured  by  Mr.  Collomb :  it 
seemed  to  have  the  qualities  which  he 
mentions;  but  it  had  less  suppleness  and 
softness  than  siik  scoured  with  soap. 

The  substance  taken  from  the  silk  in 
the  scouring,  appears  to  be  of  an  animal 
nature,  and  therefore  the  soap-suds  used 
in  that  operation  soon  become  putrid ; 
when  separated  from  the  silk,  it  is  easily 
dissolved  in  water,  but  not  in  alcohol. 
Though  not  of  a  vegetable  nature,  it  may 
with  considerable  propriety  be  called  a 


SIL 


SIL 


eiim.  That  part  which  gives  it  the  vol- 
low  colour,  is  soluble  in  alcohol,  and  when 
it  is  separated  the  gum  becomes  brown. 
It  is  not  improbable,  that  this  colour  is 
occasioned  by  the  heat,  to  which  it  is  ex- 
posed in  the  boiling,  because  when  only 
the  yellow  colouring  part,  is  separated  by 
Mr.  lieaume's  process,  which  will  pre- 
sently be  described,  the  silk  is  whiten- 
ed. 

In  Mr.  Collomb's  process,  the  gum  is 
separated,  and  takes  with  it  only  some  ot 
the  colouring  particles  ;  and  in  the  pro- 
cess of  scouring  by  soap,  the  gum  and 
the  yellow  colouring  particles,  are  carried 
oil' together.  . 

Berthollct  boiled  some  yellow  silk,  in  a 
retort,  where,  as  the  vapours  did  not  es- 
cape so  freely,  as  from  an  open  vessel,  a 
degree  of  heat  must  have  been  produced, 
superior  to  that  of  water  boiling,  in  the 
open  air.  After  having  been  boiled  for 
tour  hours,  the  silk  has  lost  one-iourth  ot 
its  weight,  but  it  lias  almost  entirely  re 
tained  its  colour. 

The  same  chemist  boiled  another  pat- 
tern, in  the  same  way,  in  a  quantity  of 
water,  impregnated  with  common  salt 
it  became  whiter,  but  lost  less  ot  its 
weight,  though  the  degree  of  heat  was 
certainly  increased,  by  the  addition  ot  the 
salt,  which  restrained  the  evaporation  ot 
the  water  :  possibly  a  part  ot  the  salt  had 
united  with  the  silk.  Experiments  might 
be  made  with  other  salts :  aud  perhaps 
we  should  find  some,  that  without  m 
luring  the  silk,  might  be  more  usetul 
In  dissolving  the  gum,  and  colouring  par 
tides.  ,  _  . 

When  the  silk  is  intened  tor  the  manu 
facture  of  blonds  and  gauses,  its  natural 
elasticity  and  stiffness,  should  be  pre 
served  :  the  greatest  part  of  what  is  pro 
duced  in  France,  is  of  a  yellow  colour 
but  it  is  the  white  China  silk,  that  is  prm 
cipally  used  for  these  purposes  :  this  is  so 
dear,  that  the  French  manutacturers  can 
not  Me  with  theEnglish,  irom  whom  they 
get  it,  as  the  English  always  reserve 
finest  for  their  own  manufactures,   ft  has 
therefore  been  a  desideratum,  to  hud  out 
the  means,  of  depriving  the  yellow  si  k  ot 
its  elasticity    Mr.  Beaume  Has  solved 
this  interesting  problem,  but  has  kept  his 
process  secret;  some  artists,  however 
to  whom  he  has  intrusted  it,  or  who  had 
been  led  to  the  discovery,  by  their  own 
observations,  succeeded  in  the  execution 
of  it ;  but  the  process  appears  to  be  liable 
to  accidents,  which  by  occasioning  loss, 
increase  expense  :  so  tnat  hitherto,  not- 
withstanding the  advantages  it  presents, 
it  has  not  been  carried  into  execution. 


The  following  is  an  account  of  what  has 
transpired  respecting  it. 

A  mixture  is  made  with  twelve  ounce* 
of  muriatic  acid,  and  forty-eight  pounds 
of  alcohol,  in  which  six  pounds  of  silk  are 
immersed.  This  liquor  being  poured  off, 
as  soon  as  it  is  slightly  coloured,  alcohol 
alone  is  to  be  poured  over  the  silk,  till  no 
more  colouring  matter  is  taken  up  by  it. 
A  mixture  of  alcohol  and  acid  like'th". 
first,  is  then  to  be  poured  on  the  silk,  in 
which  it  is  to  stand  two  or  three  days. 
Lastly,  the  silk  is  to  be  washed  in  cold 
water.  The  muriatic  acid  must  be  pure, 
and  not  contain  any  nitric  acid,  which 
makes  the  silk  yellow.  To  give  it  an  uni- 
form white  colour,  seems  to  be  one  of  the 
most  difficult  parts  of  the  process,  espe- 
cially when  the  operation  takes  place  on 
large  quantities.  There  is  likewise  great 
difficulty  in  dyeing  the  whitened  silk,  so 
as  to  prevent  its  curling ;  it  ought  cer- 
tainly to  be  kept  constantly  stretched, 
during  the  drying.  The  alcohol  that  has 
been  impregnated  with  the  colouring  part, 
must  be  again  separated  from  it,  so  as  to 
serve  for  subsequent  operations,  other- 
wise  the  process  would  be  too  expensive ; 
for  this  purpose,  it  is  to  be  distilled  by 
a  gentle  heat,  in  a  glass  or  stone-ware 
vessel. 

It  appears  from  the  experiments  above 
related,  that  the  muriatic  acid,  is  useful 
in  this  process,  by  softening  the  gum, 
and  thus  assisting  the  alcohol  to  dis- 
solve the  colouring  particles,  combined 
with  it 

Mr.  Giobert,  has  lately  given  another 
process,  for  destroying  the  colouring  mat- 
ter of  silk,  preserving  its  gluten,  and 
scouring  it  at  little  expense,  without  using 
soap. 

He  employs  oxygenized  muriatic  acid, 
largely  diluted  with  water,  so  as  to  de- 
stroy the  colouring  matter,  without  acting 
upon  the  silk  itself,  farther  than  giving  it 
a  yellow  tinge,  its  common  effect  upon 
animal  substances;  and  this  tinge  he  takes 
off,  by  sulphuric  acid.  After  these  alter- 
nate immersions,  the  silk  may  be  scoured 
in  boiling  water.  He  confesses,  however, 
that  to  operate  upon  the  gluten  by  the 
acids,  so  that  the  water  shall  carry  it  off, 
and  yet  not  to  weaken  the  silk,  is  an  ope- 
ration too  nice,  for  the  generality  of  work- 
men. 

The  preparation  with  alum,  must  be 
considered  as  one  of  the  general  opera- 
tions in  dyeing  silk;  for  without  alum- 
ing,  the  greatest  part  of  the  colours  ap- 
plied, would  possess  neither  beauty  nor 
durability. 

The  preparation  with  alum,  consists  in 


SIL 


SIL 


mixing  in  a  tun,  or  vat,  about  forty  or  fifty 
pails  of  water,  with  forty  or  fifty  pounds 
of  Roman  alum,  that  has  been  previous- 
ly dissolved  in  warm  water ;  this  must 
be  carefully  stirred  during  the  mixture, 
to  ^.prevent  the  crystallization  of  the 
alum. 

After  having  washed  and  bathed  the 
silk,  and  wrung  it  out  with  the  jack  and 
pin,*  in  order  to  separate  any  soap  it  may 
have  retained,  it  is  immersed  in  the  aium 
liquor  where  it  is  left  tor  eight  or  nine 
hours  ;  after  which  it  is  wrung  out  by 
hand  over  the  vat,  and  washed  in  a  stream 
of  water. 

In  the  above  quantity  of  liquor  150  lbs 
of  silk,  may  be  prepared  without  the  ad- 
dition of  any  more  alum  ;  but  when  it  be- 
gins to  grow  weak,  which  those  who  are 
in  the  habit  of  employing  it,  can  easily 
distinguish  by  the  taste,  twenty  or  twenty 
five  pounds  of  dissolved  alum,  must  be 
added  as  before,  and  this  addition  must 
be  repeated,  until  the  liquor  acquires  a 
disagreeable  smell ;  and  then  it  may  be 
employed,  in  the  preparation  of  stuff's,  in- 
tended for  darker  colours,  such  as  browns 
and  marones,  till  it  has  lost  all  its 
strengh. 

The  preparation  of  silk  with  alum,  is 
always  made  in  the  cold,  because  when 
the  liquor  is  employed  hot,  the  lustre  of 
the  silk  is  liable  to  be  impaired. 

SILK-WORM,  or  thaUna  Bombyx 
Mori,  is  a  native  of  China,  where  it  propa- 
gates ilself  on  the  mulberry-tree,  the 
leaves  of  which  serve  as  its  only  natural 
food.  From  the  labours  of  this  valuable 
insect,  we  obtain  silk.  The  worm  is 
batched  from  yellowish  eggs,  the  size  of 
which  is  rather  smaller,  than  that  of  mus- 
tard-seed ;  and  which  are  laid  by  a  spe- 
cies of  white  moth,  resembling  a  butter- 
fly- 

When  the  egg  is  batched,  after  being 
exposed  to  a  warm  temperature,  of  from 
sixty  to  seventy  degrees  of  Fahrenheit, 
for  a  few  days,  a  smali  black  worm  bursts 
forth,  which"  is  very  eager  for  food,  and 
ought  to  be  supplied  with  the  most  ten- 
der mulberry -leaves.  These  will  be  gree- 
dily eaten,  for  about  six  days,  at  which 
period  the  worm  is  seized  with  a  lethar- 
gic sleep,  for  three  days  ;  when  it  changes 
its  skin.  The  creature  now  begins  to  eat 
again,  for  five  or  six  days,  till  it  becomes 


subject,  to  a  second  sickness  or  sleep,  ot 
a  similar  duration  A  third  and  fourth 
stage  of  equal  length  succeeds,  so,  that 
in  about  thirty -two  or  thirty-six  days,  the 
silk  worm  attains  its  full  growth,  being 
in  this  climate  from  one  to  two  inches, 
but,  in  the  warmer  countries,  from  three 
to  four  inches  in  length. 

After  these  four  successive  revolutions, 
the  insect  devours  its  food  with  great 
avidity  for  five  or  six  days  longer  ;  at  the 
end  of  which  it  becomes  sickiy,  and  in  a 
manner  transparent,  when  it  requires  no 
farther  nourishment :  at  this  period,  it 
endeavours  to  find  a  convenient  spot  be- 
tween the  branches,  in  a  dark  corner,  and 
begins  to  spin  ;  winding  the  silk  which  it 
draws  from  its  bowels,  around  its  own 
body,  in  an  egg-shaped,  roundish  ball, 
denominated  a  cocoon.  In  this  state,  the 
worm  remains  for  a  fortnight,  and  up- 
wards, inclosed  in  the  centre  of  its  silky 
habitation,  whence  it  bursts  forth  in  the 
form  of  a  whiteish  moth,  the  wings  of 
which  are  marked  with  yellow  or  brown 
lines  ;  each  female  lays  from  3  to  500 
eggs,  within  two  or  three  days,  when  she 
dies  without  tasting  any  food  :  and  the 
male  generation  perishes  in  24  hours,  af- 
ter having  propagated  its  species.  It  de- 
serves to  be  remarked,  that,  during  the 
first  day  of  its  labours,  the  silk-worm  spins 
only  the  exterior,  irregular  texture,  which 
is  known,  in  commerce,  under  the  name 
of  floret,  or  coarse  silk,  serving  for  infe- 
rior stockings,  gloves,  &c. 

On  the  second  or  third  day,  it  begins  to 
manufacture  fine,  connected  filaments, 
extending  several  hundred  yards  in  length; 
and,  after  this  useful  work,  the  creature 
completes  its  task,  by  forming  its  oval 
solid  case,  that  resembles  thin  parchment, 
and  in  which  it  rests  with  safety,  till  it 
emerges  in  the  shape  of  a  butter-fly. — 
Those  cocoons,  however,  which  are  intend- 
ed for  the  production  of  silk,  ought  to  be 
selected  within  a  week,  and  exposed  to  a 
hot  oven,  in  which  bread  has  been  previ- 
ously baked;  with  a  view  to  prevent  the 
worm  from  cutting  the  silk  :  on  the  con- 
trary, such  as  are  designed  for  breeding, 
ought  to  be  carefully  selected,  namely, 
one  male  to  each  female  :  the  cocoons  of 
the  former,  being  somewhat  pointed  at 
one  end,  with  those  of  (he  latter  are  ge- 
nerally of  a  larger  size. 


*  This  is  a  contrivance  for  wringing  more  strongly,  than  can  be  done  by  the  hands 
alone  ;  the  pin  introduced  through  the  hank  at  one  end,  or  into  a  twist  of  the  cloth, 
is  secured  in  a  fixed  position,  while  the  other  end  or  twist  is  fixed  to  the  hook  of  the 
jack,  which  can  be  forcibly  turned  round,  by  means  of  a  winch  connected  with  it 
When  the  degree  of  force  is  not  necessary,  and  the  hands  only  are  employed  in  the 
operation,  it  is  called,  wringing  out  by  band. 


SIX, 


SIL 


Having  thus  stated  the  various  changes 
which  silk-worms  undergo,  we  shall  pro- 
ceed to  point  out,  the  most  proper  vege- 
tables for  their  subsistence.  The  best 
adapted  for  this  purpose,  are  the  leaves 
of  the  black  and  white  mulberry -tree.  As, 
however,  mulberry-leaves  cannot  always 
be  procured  in  sufficient  quantity,  the  in- 
sects, if  kept  in  a  warm  place,  may  be 
occasionally  fed  with  those  of  lettuces. 
The  young,  (neither  moist  nor  withered,) 
leaves  of  black-berries,vines,cowslips,ash, 
and  primroses,  have  also  been  advantage- 
ously employed  for  this  purpose ;  and  it  is 
asserted,  that  elm-leaves  may  be  safely 
given  to  them  ;  though  some  breeders  ob- 
serve, that  such  food  inevitably  causes 
their  destruction. 

In  the  management  of  silk-worms,clean- 
liness  is  an  object  of  the  first  importance  : 
hence,  to  facilitate  the  rearing  of  these 
profitable  creatures,  in  this  climate,  the 
Rev  Mr.  Swayne  has  contrived  an  inge- 
nious apparatus,  b-  m<  ana  of  which,  targe 
numbers  may  be  bred  in  a  small  compass. 
It  consists  of  a  wooden  frame,  four  feet 
two  inches  in  height;  each  side  being 
sixteen  and  an  half  inches  wide,  and  di- 
vided into  eight  partitions,  by  means  of 
small  wooden  grooves,  into  which  are  in- 
troduced sliders,  that  may  thus  be  di  " 
in  or  out,  at  pleasure.  The  upp< 
is  of  paper,  and  is  destined*  f<  eceffc* 
tion  of  the  Worms,  as  the  eggs 

are  ha;  ed.  Tin  ..ext  are  formed 
of  cal  ids  of  which  are  about 

on  f  an  inch  asunder ;  and  are  de- 

si  lor  them,  when  somewhat  increas- 
ed m  size.  The  five  lower  sliders,  are 
constructed  of  wicker-work,  with  open- 
ings about  a  quarter  of  an  inch  square, 
through  which  the  dung  descends.  Be- 
neath all  these  are  placed  paper-sliders, 
to  prevent  the  excrements  from  falling  on 
those  which  are  beneath  them.  For  a 
more  detailed  account  of  this  contrivance, 
the  reader  is  referred  to  the  7th  volume  of 
the  Transactions  of  the  Society  for  the 
Encouragement  of  Arts,"  8cc.  where  it  is 
fully  described,  and  illustrated  with  an  en- 
graving. 

For  the  successful  rearing  of  silk- 
worms, two  essential  objects  ought  to  be 
attended  to. 

1.  A  sufficient  plantation  of  mulberry- 
trees. 

2.  A  proper  stock  of  eggs  for  hatching, 
obtained  from  a  climate  similar  to  that  in 
which  they  are  to  be  bred.  Besides,  it 
will  be  advisable  to  keep  the  latter  in  a 
cool,  but  not  in  a  cold  place,,  till  the  ten- 
der mulberry  leaves  arc  secured  from  the 
effect  of  night-frosts-  The  room  in  which 
the  insects  are  managed,  should  be  lofty, 


dry,  and  rather  dark  than  too  light.  In 
short,  they  ought  to  pass  through  their 
different  stages  of  life,  in  an  uniformly 
warm  temperature,  not  exceeding  that  of 
summer  heat. 

The  quality  of  silk  greatly  depends  on 
the  manner,  in  which  the  raw  threads  are 
manufactured.  In  order  to  wind  them  oft' 
the  cocoons,  they  are  immersed  into  hot 
water,  for  a  minute  or  longer,  when  they 
are  taken  out  and  reeled  by  means  of  a 
machine ;  the  threads  are  next  twisted, 
and  at  length  woven  into  ribbons,satins,&c. 

The  reader  may  consult  the  2d,  4th, 
5th,  and  7th  volumes,  of  the  "  Transac- 
tions (f  the  Society  of  Arts"  8cc.  in  which 
the  various  expedients  practised  by  silk- 
cultivators,  are  fully  related.  Some  prac- 
tical remarks  likewise  occur,  in  Mr.  Ber- 
tezen's  "  Thoughts  or,  the  different  kinds  of 
Food,  given  to  Si  I i -worms,"  Sec-  (8vo.  p. 
47,  1*.  Bew,  1789;)  u  treatise  wc  h  of 
perusal. 

The  breeding  of  silk-worms,  says  Dr. 
Mease,  was  much  attended  to,  before  the 
American  revolution,  in  the  United  States, 
and  from  the  success  which  attended  the 
efforts,  of  many  individuals  in  various 
parts  of  the  continent,  from  Georgia  to 
Connecticut,  it  was  at  first  thought  that 
lilk  \  Hild  be  a  profitable  article  to  attend 
to,  but  mature  reflection  has  convinced 
us,  that  our  industry  can  be  more  profi- 
tably directed  to  other  objects.  Those 
however,  who  may  wish  to  see  the  mode 
of  breeding  silk  worms,  may  consult  the 
1st  vol.  of  the  Trans  Amer.  Philo.  Socie- 
ty and  for  observations  on  the  advanta- 
ges of  the  culture  of  silk,  Carey's  Ameri- 
can Museum,  and  a  pamphlet  published 
about  1790,  by  Mr.  Aspinwall,  in  Phila- 
delphia. 

In  addition  to  the  preceding  obser- 
vations, we  have  only  to  add,  that  if 
the  rearing  of  the  silk-worm  was  at- 
tended to  in  the  United  States  especial- 
ly at  this  period,  it  would  be  profitable, 
and  render  the  country  in  this  respect, 
independent  of  other  nations.  We  have 
seen  silk  produced  from  the  worm  in  this 
country,  made  into  a  fabric,  equal  to  the 
foreign. 

SILVER. — Silver  is  a  metal  of  a  pure 
white  colour,  very  malleable,  soft,  fusible 
at  a  full  red  heat,  but  not  oxidable  by  ex- 
posure to  the  air  while  melted.  It  is  solu- 
ble with  ease  in  nitrous  acid,  and  precipi- 
table  from  its  solution  in  the  form  of  a 
white  curd  by  muriatic  acid,  or  any  of  the 
neutral  muriats. 

For  the  ores  of  silver,  and  the  different 
modes  of  reduction,  see  Ore. 

The  following  are  the  most  prominent 
characters  of  this  metal. 


SIL 


SIL 


Silver  is  a  metal  of  a  beautiful  white  co- 
lour, perfectly  free  from  taste  and  smell. 
The  colour  is  very  distinguishable  from 
that  of  every  other  metal,  being  a  pure 
brilliant  white,  free  from  any  other  admix- 
ture of  hue-  Its  specific  gravity,  when 
simply  fused  in  mass,  is  about  10.4,  which 
is  somewhat  increased  by  hammering  or 
lamination,  but  less  so  than  most  other 
metals.  It  is  a  soft  metal,  being  easily 
scratched  by  copper.  It  is  considerably 
elastic,  and  when  hardened  by  alloying,  is 
highly  sonorous,  and  even  in  small  quan- 
tity much  increases  the  sonorousness  of 
the  alloys  of  Copper,  as  mentioned  un- 
der that  article.  Silver  is  one  of  the  most 
extensible  metals  that  we  are  acquainted 
with  ;  its  ductility  is  only  less  than  that 
of  gold,  in  consequence  of  which  it  may 
be  beaten  out  into  extremely  fine  leaves, 
and  drawn  out  into  wire  thinner  than  the 
finest  human  hair.  For  this  latter  pur- 
pose, however,  a  small  alloy  of  copper  is 
found  necessary,  though  less  than  that  of 
standard  silver,  which  is  one-twelfth. 
Hence  the  silver  procured  from  the  silver 
and  silver-gilt  wire  used  for  laces,  embroi- 
dery, and  other  ornamental  purposes, 
bears  a  higher  price  than  any  other  usual- 
ly met  with.  This  metal  is  also  very  te 
nacious,  so  that  a  wire  a  tenth  of  an  inch 
diameter  will  support  about  240  lbs.  with- 
out breaking. 

Silver,  when  quite  free  from  alloy,  melts 
in  a  moderately  intense  red-white  heat,  so 
that  a  plate  about  the  dimensions  of  the 
thinnest  pasteboard,  will  scarcely  support 
the  fullest  heat  of  a  very  brisk  fire  in  a 
common  grate.  When  in  fusion,  if  pure, 
the  surface  is  most  strikingly  brilliant  and 
beautiful,  and  like  a  white  polished  mir- 
ror; but  as  it  congeals,  it  becomes  of  a 
clean  dead  white.  If  cooled  hastily,  the 
surface  as  it  fixes  shoots  up  into  small  ir- 
regular projections  with  some  little  force, 
so  as  to  disperse  a  few  particles  of  that 
part  of  the  metal  still  in  fusion.  Hence, 
in  the  delicate  business  of  the  assay,  arises 
the  precaution  of  cooling  melted  silver 
very  gradually  while  it  is  fixing.  Pure 
silver  is  not  sensibly  volatilized  by  being 
kept  in  a  heat  not  much  above  its  melting 
point  for  any  length  of  time,  though  when 
mixed  with  another  metal  which  is  itself 
volatile,  either  in  the  metallic  or  oxided 
state,  a  little  of  the  silver  is  then  dissi- 
pated. Silver  is  a  perfect  metal,  that  is,  it 
does  not  oxidate  by  being  kept  in  fusion 
whilst  exposed  to  air.  This  position  how- 
ever, though  sufficiently  accurate  for  all 
practical  purposes,  requires  some  limita- 
tion ;  for  when  this  metal  is  intensely 
heated  with  access  of  ah',  the  support  on 
which  it  stands  gradually  becomes  yellow, 


owing  to  the  formation  of  an  oxyd  of  sil- 
ver. 

The  pure  oxyds  of  silver  are  reducible 
to  metallic  silver  by  mere  heat,  when  not 
in  contact  with  any  earth  or  other  sub- 
stance with  which  "they  can  vitrify.  Un- 
der the  blow-pipe,  silver,  when  intensely 
heated,  emits  copious  fumes,  which  will 
render  brown  a  surface  of  gold  exposed 
to  it,  and  consist  of  the  silver  volatilized 
by  the  extreme  heat.  The  pure  oxyd  can- 
not be  prepared  by  mere  heat,  but  is  rea- 
dily furnished  by  the  precipitation  of  the 
acid  solutions  by  an  alkali.  In  this  state 
it  is  insoluble  in  water,  free  from  taste, 
and  cannot  be  sublimed  ;  but  when  heat- 
ed per  se,  it  returns  to  its  metallic  state, 
except  the  part  immediately  in  contact 
with  any  earthy  matter  which  becomes 
fixed  by  vitrifying  with  it. 

Silver  is  nearly  unalterable  by  simple 
exposure  to  air  and  moisture,  so  that  it  is 
incapable  of  rusting.  A  polished  surface 
of  this  metal  will  remain  bright  for  some 
time  in  a  pure  air,  free  from  sulphureous 
and  animal  vapours;  by  degrees,  however, 
the  metal  becomes  dull  and  brownish,  and 
after  a  while,  a  very  slight  coating  forms 
on  its  surface,  which  rubbing  with  any 
soft  powder  will  take  off,  and  the  bright- 
ness will  be  restored  with  scarcely  any 
loss  of  weight,  the  outer  coating  long  pro- 
tecting the  metal  within  from  further 
change.  This  takes  place,  however,  much 
more  rapidly  when  the  silver  is  alloyed, 
(as  in  the  common  plate)  than  when  pure. 

In  general,  the  tarnish  of  silver  is  in  too 
small  a  quantity  to  be  examined,but  when 
this  metal  has  been  exposed  for  a  very 
long  series  of  years  to  the  common  air  of 
towns  and  inhabited  places,  the  corrosion 
penetrates  deeper,  and  the  altered  part 
will  readily  peel  off.  This,  however,  is 
not  the  pure  oxyd,  but  the  sulphuret,  as 
was  ascertained  by  Proust,  the  properties 
of  which  will  be  afterwards  described,  so 
that  we  know  of  no  simple  oxyd  of  silver 
formed  spontaneously  in  the  air. 

Water  has  no  effect  whatever  on  silver 
at  any  temperature,  and  is  not  decom- 
posed upon  it. 

Though  silver  at  no  temperature  under- 
goes combustion  by  simple  contact  of  com- 
mon air,  or  oxygen  gas,  yet  it  burns  to- 
tally and  most  beautifully  in  the  electric 
and  especially  the  galvanic  circles. 

The  sulphuric  acid  has  no  effect  on  sil- 
ver in  the  cold  in  any  state  of  dilution,  but 
when  the  acid  is  concentrated  and  a  boil- 
ing heat  is  employed,  effervescence  be- 
gins, an  abundance  of  very  pure  sulphu- 
reous acid  gas  is  given  out  (as  with  this 
acid  and  mercury)  and  the  metal  is 
changed  to  a  white  pulverulent  mass,  or 


SIL 


SIL 


is  dissolved  entirely  into  a  dense  clear  li- 
quid if  ilie  quantity  of  the  acid  is  about 
four  times  that  of  the  silver,  which  latter 
should  be  added  in  small  shreds  or  grains. 

This  solution  is  extremely  styptic  and 
requires  an  excess  of  acid.  By  evapora- 
tion it  furnishes  small  white  brilliant  nee- 
dled crystals. 

The  sulphureous  acid  has  no  action  on 
silver,  but  readily  combines  with  its  oxyd. 
This  solution  crystallizes  spontaneously 
in  small  pearl -gray  brilliant  grains  unal- 
tered by  light. 

The  nitric  acid  dissolves  silver  easily, 
and  in  large  quantity,  and  is  the  acid  con- 
stantly employed  for  this  purpose  in  the 
arts.  The  concentrated  acid  should  be 
diluted  with  from  two  to  four  parts  of  wa- 
ter. Very  soon  after  the  silver  is  im- 
mersed in  the  acid,  a  strong  effervescence 
begins,  much  nitrous  gas  is  given  out, 
which  forms  a  copious  orange-coloured 
vapour  as  it  escapes  from  the  vessel,  and 
the  acid  assumes  a  light  blue-green  co- 
jour,  which  is  independent  of  any  copper 
which  the  silver  may  contain,  and  is  owing 
to  the  solution  of  a  portion  of  the  nitrous 
gas  in  the  acid.  If,  however,  the  silver 
contains  copper,  this  increases  the  blue- 
ness,  and  the  colour  remains  after  the  so- 
lution is  cold  and  saturated,  which  is  not 
the  case  when  the  silver  is  pure.  A  con- 
siderable heat  is  excited  by  the  action  of 
the  acid  on  the  silver,  which  also  much 
assists  in  the  rapidity  of  the  process,  so 
that  where  the  quantity  of  each  is  at  all 
considerable  no  artificial  heat  is  required. 
The  solution  is  made  very  conveniently 
by  putting  the  silver  (granulated  or  in 
shreds)  into  a  decanter  or  matrass,  add- 
ing the  acid,  and  to  it  about  four  parts  or 
more  of  hot  water,  and  setting  it  under  a 
chimney  to  draw  oft'  the  fumes.  The  so- 
lution then  begins  almost  immediately, 
and  goes  on  with  increasing  violence  for 
a  time  and  then  continues  steadily  till  the 
silver  is  dissolved  or  the  acid  saturated, 
w  ithout  requiring  any  artificial  heat. 

When  the  silver  contains  a  little  gold, 
as  is  the  case  with  a  large  proportion  of 
the  standard  silver  in  use,  the  gold  is  left 
behind  after  the  solution  of  the  silver  in 
the  form  of  a  black  powder,  which,  when 
collected,  and  fused  with  a  little  borax, 
appears  in  its  reguline  state- 

When  the  nitric  acid  contains  either 
muriatic  or  sulphuric  acid  a  milkiness  is 
perceived  as  soon  as  the  effervescence  be- 
gins, owing  to  the  separation  of  the  first 
portions  of  the  dissolved  silver  from  the 
nitric  acid  in  the  form  of  an  insoluble  sul- 
phat  or  muriat.  Where  the  quantity  of 
these  foreign  acids  is  but  small,  it  does 
not  materially  impede  the  process,  and 

O   L.  II. 


these  insoluble  salts,  after  the  nitric  acid 
is  fully  saturated,  fall  to  the  bottom  by 
standing  at  rest  for  some  hours. 

Liquid  nitrat  of  silver  is  perfectly  clear 
and  colourless  in  case  the  silver  was  pure; 
but  if  standard  silver  be  employed,  the 
colour  is  a  light  blue,  owing  to  the  pre- 
sence of  copper.  When  at  all  concen- 
trated, its  taste  is  excessively  styptic  and 
bitter,  and  it  rapidly  corrodes  the  skin  of 
the  tongue.  Even  in  extreme  dilution, 
the  bitter  styptic  metallic  taste  is  very  sen- 
sible, and  it  remains  for  a  long  time  in  the 
palate.  This  salt  blackens  every  part  of 
the  skin,  and  all  other  animal  matters. 
The  blackness,  however,  does  not  come 
on  till  after  the  part  has  been  exposed  for 
some  time  to  the  light,  and  is  therefore 
particularly  hastened  by  sunshine ;  but 
the  mutual  action  between  the  salt  and 
the  skin,  is  so  sudden,  when  the  solution 
is  concentrated,  that  a  few  seconds  of  con- 
tact will  be  sufficient  infallibly  to  produce 
the  effect,  though  it  be  carefully  washed 
oft' immediately  after.  This  stain  lasts  for 
several  days,  and  only  goes  off  by  the  na- 
tural change  of  the  cuticle,  so  that  in  dead 
animal  matter  it  is  indelible. 

The  blackness  is  owing  to  a  reduction 
of  the  metal  in  excessively  minute  parti- 
cles ;  for  when  examined  in  a  strong  sun- 
shine with  a  powerful  microscope,  the 
particles  of  metallic  silver  may  be  distin- 
guished.   See  Ink,  Indelible. 

Most  vegetable  substances  are  also 
stained  by  this  salt,  though  in  a  less  de- 
gree, and  less  permanently. 

When  this  solution  is  sufficiently  con« 
centrated,  it  readily  crystallizes  on  cool- 
ing. The  form  of  these  crystals  is  gene- 
rally six-sided,  or  square  thin  plates,  often 
ranged  like  the  sticks  of  a  fan,  and  form- 
ing very  beautiful  groups.  This  salt  is 
not  deliquescent,  and  is  soluble  in  about 
four  parts  of  cold  and  much  less  of  toil- 
ing water. 

It  appears  to  contain  but  little  water  of 
crystallization,  for  when  mod<*'ately  heat- 
ed it  melts,  and  may  be  keri  at  that  state 
without  losing  more  than  one  per  cent,  of 
its  weight.  By  cooling  it  concretes  into 
a  dark  gray  mass  which  is  the  nitrat 
scarcely  altered,  and  when  redissolved  in 
water,  will  ag^'n  crystallize.  This  gray 
solid  nitrat  farms  a  very  valuable  caustic 
for  the  use  of  surgeons,  and  for  conve- 
nience is  cast  in  oiled  moulds  into  pieces 
about  the  size  of  pencils,  which  are  called 
lunar  caustic,  or  lapis  bifernalis.  This  is 
actually  prepared,  however,  without  the 
trouble  of  crystallization,  simply  by  eva- 
porating the  nitrat  of  silver  to  the  proper 
degree,  and  cooling  the  residue  in  the  pro- 
per moulds.  When  one  of  these  pencils 
o  A 


SIL 


SIL 


is  broken  across,  it  presents  a  radiate*! 
texture.  The  degree  of  causticity  of  this 
substance  is  by  no  means  so  powerful  as 
that  of  the  solid  alkalies,  for  it  corrodes 
the  cuticle  with  difficulty,  and  it  requires 
some  hours  to  destroy  the  surface  of  the 
flesh. 

The  composition  of  nitrat  of  silver  is 
given  by  Proust,  as  follows  : 
Silver      64  £  ~q 
Oxygen  63 
Nitric  acid  -  30 

100 

Nitrat  of  silver  detonates  most  violent- 
ly with  phosphorus. 

Phosphorus  will  also  reduce  the  nitrat 
of  silver  in  the  moist  way. 

Hydrogen  also  rapidly  reduces  the  ni- 
trat of  silver,  and  during  its  reduction  it 
passes  through  various  shades  of  brown, 
till  it  acquires  the  metallic  lustre. 

Nitrat  of  silver  is  also  reduced  very  rea- 
dily upon  charcoal  by  the  sun's  rays,  or 
by  exposure  to  a  heat  of  boiling  water 
without  the  assistance  of  light. 

Silver  is  precipitated  from  its  nitric  so- 
lution by  mercury.  If  the  solution  con- 
tains both  silver  and  mercury,  and  the 
precipitating  metal  be  also  a  compound 
of  mercury  and  silver,  a  curious  and  beau- 
tiful precipitation  of  a  brilliant  alloy  of 
these  two  metals  is  deposited  in  an  arbo- 
rescent form,  which  has  been  called  the 
*drbor  Diana,  or  Silver  Tree. 

Nitrat  of  silver  is  decomposed  by  the 
fixed  alkalies,  pure  or  carbonated,  and  by 
the  alkaline  earths. 

Ammonia  first  gives  a  precipitate  which 
it  speedily  redissolves,  and  forms  with 
some  particulars  in  the  management  the 
fulminating  silver,  which  will  be  present- 
ly described.  Carbon  at  of  ammonia  gives 
a  v^ite  or  a  dark  precipitate,  according 
as  it  is  more  or  less  saturated  with  carbo- 
nic acid.  All  these  oxyds  turn  blackish 
by  exposui,  to  light. 

Many  othei  metals  also  separate  silver 
from  its  solution  \n  this  and  other  acids, 
and  particularly  copper,  which  is  employ- 
ed largely  for  this  purpose  by  the  re- 
finers. In  assaying  goi-J  (as  mentioned 
under  the  article  Acs  ay/,  the  cupelled 
button  of  gold  and  silver  is  tinted  by  ni- 
tric acid  to  dissolve  out  the  s'Jver  and 
leave  the  gold  pure.  After  this  process 
(which  is  called  parting  by  aquafortis,)  a 
nitrat  of  silver  is  left,  which,  when  a  suf- 
ficient quantity  is  collected,  is  thrown  into 
a  copper  bason,  sometimes  also  with 
pieces  of  copper  immersed,  and  the  silver 
Is  reduced  in  its  perfect  metallic  state  in 
the  form  of  thin  brittle  leaves,  and  the 


bason  now  contains  nitrat  of  copper.  The 
latter  again  decomposed  by  lime  yields 
the  pigment  Verditer. 

Nitrated  silver  is  also  decomposed  by  a 
great  variety  of  alkaline  and  earthy  salts, 
particularly  by  the  sulphats,  muriats, 
phosphals,  &.C-;  that  is,  by  all  those  whose 
acids,  united  with  silver,  produce  an  in- 
soluble salt. 

Several  of  the  metals  are  found  to  com- 
bine with  the  acids  in  two  proportions, 
one,  where  the  ingredients  are  in  mutual 
saturation,  or  else  where  the  acid  is  in 
excess,  and  the  other,  where  the  metallic 
oxyd  predominates. 

All  the  solutions  of  silver  are  blacken- 
ed immediately  by  sulphuretted  hydro- 
gen, either  in  the  gasseous  or  liquid  states, 
and  all  the  solid  sulphurets  produce  the 
same  change  on  silver,  as  will  be  present- 
ly mentioned. 

A  compound  acid,  extremely  useful  for 
dissolving  silver  when  mixed  with  copper 
and  some  other  metals,  has  been  discover- 
ed by  Mr.  Keir.  It  is  formed  by  dissolv- 
ing one  part  of  nitre  in  about  eight  or  ten 
parts  by  weight  of  strong  sulphuric  acid. 
When  pieces  of  silver  are  thrown  into  this 
acid  (undiluted  with  water)  and  a  heat  of 
from  100°  to  200°  is  applied,  an  efferves- 
cence of  nitrous  gas  takes  place,  and  the 
silver  is  dissolved.  This  makes  a  very 
dense  heavy  solution,  which  readily  con- 
cretes by  cooling,  but  may  be  moderately 
diluted  with  water,  without  becoming  tur- 
bid. This  compound  acid  (which  may  be 
termed  the  nitro-sulphuric)  dissolves  about 
a  fifth  or  a  sixth  of  its  weight  of  silver,  and 
with  much  more  ease  than  the  sulphuric 
acid  singly  would  do.  The  quantity  of 
nitrous  gas  given  out  in  the  process  seems 
to  be  less  in  proportion  as  that  of  the  nitre 
is  greater.  The  nitro-sulphuric  acid,  un 
diluted,  also  oxydates  and  partly  dissolves 
tin  and  mercury,  but  it  hardly  touches 
copper,  lead,  gold,  or  iron.  Hence  it  is 
particularly  useful  in  recovering  the  silver 
from  the  surface  of  any  silver  plated  me- 
tal, which  is  an  object  in  large  manufac- 
tories of  plated  goods,  and  was  usually 
done  from  copper  plate  at  Birmingham 
(England)  by  more  expensive  methods. 

Sulphuric  acid  impregnated  with  ni 
trous  gas  (a  combination  first  noticed  by 
Dr.  Priestley)  dissolves  silver  with  effer- 
vescence as"  soon  as  heat  is  applied,  the 
solution  becomes  of  a  violet  colour,  and 
much  nitrous  gas  is  disengaged.  By  mo- 
derate dilution,  a  white  saline  powder  falls 
down,  which  is  redissolved  in  more  wa- 
ter. The  undiluted  solution  saturated, 
and  set  in  a  cool  place,  readily  congeals, 
but  when  diluted  slightly  it  gives  foliated 
crystals. 


SIL 


SIL 


The  carbonic  acid  has  no  action  on  sil- 
ver or  its  oxyd ;  but  a  carbonated  oxyd, 
insoluble  in  water,  is  formed  by  precipi- 
tating the  nitrat,  or  any  other  solution,  by 
a  carbonated  alkali. 

Muriatic  acid  is  usually  said  to  have  no 
action  on  reguline  silver  either  hot  or  cold. 
This  is  the  fact  (generally  speaking)  for 
the  action  in  a  moderate  time  is  so  small 
that  the  silver  hardly  appears  corroded, 
though  after  a  certain  time  and  particu- 
larly with  the  assistance  of  heat,  the  metal 
is  converted  into  an  insoluble  muriat,  and 
the  remaining* acid,  which  is  proportional- 
ly weakened,  retains  scarely  a  particle  of 
the  muriat  in  solution.  But  the  oxyd  of 
silver  readily  unites  with  this  acid,  and 
forms  a  white  curd-like  mass,  insoluble  in 
water.  This  combination,  however,  is 
more  frequently  made  by  the  mode  of  pre- 
cipitation, and  occurs  whenever  muriatic 
acid,  or  any  alkaline  or  earthy  muriat  is 
added  to  any  salt  of  silver  except  the 
prussiat.  In  this  case  if  the  solutions  are 
at  all  concentrated,  at  the  moment  of  mix- 
ture a  white  curd-like  substance  sepa- 
rates, and  speedily  sinks  to  the  bottom, 
which  is  the  muriat  of  silver ,  or  luna  cor- 
nea.  This  precipitation  is  one  of  the  most 
familiar  to  chemists,  for  being  perfectly 
msoluble  in  water,  it  shews  itself  when 
the  most  minute  quantities  of  muriatic 
acid  and  silver  are  present,  and  thus  it 
forms  a  most  useful  test  for  either  sub- 
stance. 

The  acetous  acid  has  no  action  what- 
ever upon  pure  silver,  but  it  combines 
easily  with  its  oxyd.  Acetite  of  silver  is 
readily  formed  by  adding  acetite  of  pot- 
ash to  nitrat  of  silver,  or  more  simply  by 
boiling  this  acid  on  the  carbonated  oxyd 
of  silver. 

When  silver  is  treated  with  nitrous 
acid  and  alcohol,  a  white  powder  is  depo- 
sited, which  fulminates  with  extreme  vio- 
lence, and  which,  from  the  analogy  with 
the  fulminating  mercury  produced  in  the 
same  way,  is  probably  an  oxalat  of  silver. 
This  preparation  was  discovered  by  Mr. 
Howard,  in  his  attempts  to  communicate 
to  other  metals  the  same  fulminating  pro- 
perty which  he  had  given  to  mercury,  and 
is  prepared  in  the  same  manner  as  has 
been  described  in  the  article  Mercury. 

Mr.  Cruickshank,  in  repeating  this  ex- 
periment, dissolved  40  grains  of  silver  in 
i wo  ounces  of  strong  nitrous  acid  diluted 
with  as  much  water,  and  on  heating  the 
solution  with  two  ounces  of  alcohol,  he 
obtained  60  grains  of  a  white  powder, 
which  fulminated  violently.  Brugnatelli 
has  given  the  following  method  of  prepa- 
ring the  same.  Put  1U0  grains  of  lunar 
caustic  in  a  glass,  and  pour  on  them  first 


an  ounce  of  alcohol,  and  then  as  much 
concentrated  nitrous  acid.  The  mixture 
grows  hot,  boils,  and  an  ether  is  visibly 
formed,  which  flies  off  in  vapour.  By  de- 
grees the  liquor  becomes  milky,  and  is 
filled  with  small  white  flocculi.  When 
the  liquor  has  thickened  by  this  precipi- 
tation, add  cold  distilled  water  to  suspend 
the  ebullition,  otherwise  the  precipitate 
would  be  re -dissolved;  then  collect  the 
powder,  and  dry  it  with  a  very  moderate 
heat.  This  is  the  fulminating  silver,  and 
amounts  to  more  than  half  the  weight  of 
the  lunar  caustic  employed. 

One  grain  placed  on  a  lighted  coal  de- 
tonates with  a  deafening  report,  if  touch- 
ed with  the  end  of  a  glass  tube  dipped  in 
sulphuric  acid,  or  with  the  electric  spark, 
so  that  in  violence  it  greatly  exceeds  the 
fulminating  mercury. 

The  combination  of  oxyd  of  silver  with 
ammonia,  is  remarkable  for  affording  the 
most  violently  detonating  substance  yet 
known-  This*  was  discovered  by  Berthol- 
let,  and  considering  the  multitude  of  ex- 
periments in  which  ammonia  has  been  em- 
ployed along  with  the  salts  of  silver,  it  is 
rather  surprising  that  it  was  not  sooner 
discovered  by  some  serious  accident. 

This  fulminating  ammoniacal  oxyd  is 
prepared  in  the  following  way,  according 
to  Berthollet  the  inventor,  and  the  direc- 
tions given  by  Dr.  Hlggins :  Dissolve  any 
quantity  of  silver,  perfectly  free  from  cop  - 
per, in  as  little  nitric  acid,  moderately  di 
lute,  as  is  sufficient ;  pour  off  the  clear 
solution  from  any  black  sediment  which 
may  be  left  (and  which  is  commonly  gold} 
and  add  to  it  lime  water  as  long  as  any 
considerable  precipitate  falls  down.  Edul- 
corate this  precipitate,  which  is  a  brown 
oxyd  of  silver,  and  then  lay  it  on  several 
folds  of  filtering  paper,  or  spread  it  out 
on  a  single  paper  laid  on  a  smooth  dry 
lump  of  chalk,  and  dry  the  precipitate 
thoroughly  in  the  open  air.  Set  this  oxyd 
by  for  use  in  a  well-corked  phial.  About 
one  and  one-sixth  of  an  ounce  is  obtained 
from  an  ounce  of  fine  silver.  The  caustic 
fixed  alkalies  may  be  used  instead  of  the 
lime-water,  but  they  do  not  act  with  so 
much  certainty.  This  oxyd  dissolved  in 
ammonia,  forms  the  fulminating  powder. 
For  this  purpose  add  10  or  12  grains  of 
this  oxyd  to  about  half  an  ounce  in  mea- 
sure of  liquid  ammonia,  perfectly  caustic 
and  moderately  dilute.  This  gives  a  snap- 
ping noise,  and  blackens  the  whole  oxyd 
immediately,  and  dissolves  either  a  por- 
tion of  it  only,  leaving  a  black  powder  at 
the  bottom,  or,  if  more  ammonia  is  used, 
the  whole  is  dissolved.  Tour  the  clear 
solution  off' from  the  black  powder,  if  any, 
and  expose  it  in  a  shallow  vessel  to  the 


SIL 


SIL 


air,  i  In  ten  or  twelve  hours  a  crystalline  | 
pellicle  appears  on  the  surface  of  the  am-  j 
moniacal  solution,  which  is  the  fulmina- 
ting  silver,  and  is  composed  of  a  conge- 
ries of  black  shining-  crystals.  Take  thero 
out,  whilst  still  wet,  and  lay  them  in  se- 
parate parcels  of  not  more  than  a  grain  or 
two  on  blotting-  paper,  and  let  them  dry 
in  the  air,  carefully  avoiding  to  touch 
them. 

This  fulminating  powder  has  the  fol- 
lowing properties :  even  when  still  wet,  if 
it  be  pressed  upon  with  a  hammer  or  any 
bard  body,  it  fulminates  with  extreme 
violence;  but  when  dry,  the  touch  of  a 
slender  wire  or  even  a  feather,  or  a  heat 
of  about  96°,  is  sufficient  to  make  it  ex- 
plode. Even  a  moderate  concussion  of 
the  air  is  Sufficient,  so  that  a  heap  may 
be  exploded  by  the  concussion  of  any 
other  in  its  immediate  neighbourhood. 
Sometimes  too,  it  will  go  oft' in  the  hand, 
when  carrying  from  one  place  to  another; 
so  that  in  fact,  when  it  is  once  dry,  the 
operator  should  be  prepared  for  the  ex- 
plosion at  any  time,  even  with  the  most 
careful  handling. 

Several  serious  accidents  have  happen- 
ed in  preparing  this  fulminating  silver, 
which  shew  the  necessity  of  great  precau- 
tion in  the  operator;  and,  as  all  the  cir- 
cumstances in  which  the  explosion  is  pro- 
duced are  not  as  yet  known,  he  should  on 
no  account  venture  to  prepare. more  than 
a  few  grains  at  a  time  of  this  dangerous 
compound. 

Silver  is  capable  of  uniting  with  sul- 
phur in  various  proportions.  Artificial 
sulphuretted  silvev  is  a  black  brittle  mass, 
like  the  native  sulphuret. 

A  sulphuret,  or  rather  a  hydrosulphu- 
ret,  of  silver  is  formed  whenever  this  me- 
tal is  exposed  to  sulphureous  vapours,  or 
any  liquor  containing  sulphuretted  hydro- 
gen. After  a  certain  time  the  substance 
of  the  metal  is  deeply  sulphuretted,  and 
may  be  detached  in  brittle  scales.  But  it 
takes  a  great  length  of  time  to  effect  this 
by  mere  exposure  to  sulphureous  va- 
pours. 

Some  of  the  alloys  of  silver  are  impor- 
tant. This  metal  will  unite  with  some  me- 
tals perfectly  and  without  losing  its  mal- 
leability; with  others  it  forms  a  brittle 
white  alloy,  but  with  others  it  refuses  to 
unite,  except  in  a  very  minute  proportion. 

Silver  mixed  with  gold,  dilutes  its  yel- 
low colour  more  or  less  according  to  its 
quantity.  Gold  with  one-twentieth  of  sil- 
ver is  sensibly  paler,  and  the  debasement 
of  colour  proceeds  pretty  uniformly  as  the 
silver  is  increased.  These  mixtures  are 
very  malleable,  though  somewhat  firmer, 


harder,  and  more  sonorous  than  either 
metal,  separately. 

Copper  is  the 'metal  usually  employed 
to  alloy  silver  in  the,  vast  quantity  of  this 
metal  used  for  coin  and  plate  of  all  kinds. 
The  standard  silver  is  about  eleven  parts 
of  silver  and  one  of  copper.  In  this  pro- 
portion, or  even  somewhat  more  of  the  al- 
loy, the  mixture  remains  nearly  as  white  as 
pure  silver,  but  is  much  harder,  less  fusi- 
ble, and  though  it.  remains  highly  mallea- 
ble and  ductile,  sd  as  to  bear  being  ex- 
tended into  any  shape,  and  wrought  in  a 
thousand  different  ways,  it  is  certainly 
less  ductile  and  malleable  than  a  metal 
with  less  alloy,  since  so  much  finer  a  metal 
is  required  to  be  used  in  making  silver 
wire  and  leaf.  On  account  of  the  hardness 
given  by  the  copper  alloy  it  is  much  bet- 
ter fitted  to  take  a  fine  impression,  and  is 
therefore  particularly  useful  in  coining1, 
and  in^ll  domestic  implements. 

An  alloy  of  these  two  metals  has  been 
used  in  France  for  coinage  for  many  years, 
and  called  vionnaie  dt  billon,  in  which 
the  silver  is  from  one-twelfth  to  or.e-fourth 
of  the  mass,  and  which  looks  I  ke  half- 
whitened  copper,  or  degraded  silver.  Be- 
ing on  the  whole  an  injudicious  compound 
it  is  mostly  now  laid  aside. 

Silver  unites  perfectly  with  lead  appa- 
rently in  every  proportion,  into  an  uniform 
malleable  mixture,  harder  and  whiter,  and 
less  fusible  than  pure  lead,  in  proportion 
to  the  quantity  of  silver.  The  necesshy 
of  tins  alloy  to  the  process  of  cupellation 
til  assaying  and  in  refining  silver  has  been 
already  mentioned. 

Silver  and  iron  are  generally  reckoned 
eittirely  to  refuse  to  unite  in  any  propor- 
tions, and  it  is  certain  that  when  they  are 
melted  together,  they  form,  on  cooling, 
two  perfectly  distinct  and  separable  but- 
tons, the  iron  at  top,  and  the  silver  be- 
neath it. 

Silver  unites  with  bismuth,  zinc,  anti- 
mony, and  some  other  of  the  brittle  me- 
tals, forming  brittle  alloys  which  have  not 
been  much  examined,  and  are  of  little  im- 
portance. 

SILVERING,  The  Art  of.— This  art 
consists  in  covering  the  surface  of  sub-, 
stances  with  a  thin  coating  of  silver. 
There  are  two  motives  for  this  ;  in  the 
first  place,  the  superior  beauty  of  silver 
to  that  of  the  cheaper  metals  ;  and  in  the 
second  place  its  superior  wholesomeness 
to  copper,  brass,  or  lead,  for  culinary  pur- 
poses, on  account  of  its  not  being  acted 
upon  by  vinegar  and  other  weak  acids. 

The  application  of  silver  leaf  is  made 
in  the  same  way  as  that  of  gold.  See 
Gilding. 


SIL 

As  an  ornament,  silver  is  far  inferior  to 
JVold,  from  its  great  liability  to  be  black- 
ened by  sulphureous  vapours,  which  ren- 
ders frequent  cleansing  absolutely  neces- 
sary ;  hence  it  is  inapplicable  to  the  pur- 
pose of  architectural  decoration,  and  is 
scarcely  ever  applied  except  to  utensils 
and  ornaments  of  metal.  From  the  fre- 
quent necessity  of  friction  for  the  purpose 
of  removing  the  tarnish  of  silver,  it  is  ne- 
cessary that  it  should  be  much  thicker 
than  the  most  solid  gilding,  otherwise, 
after  a  short  time,  the  silver  will  be  worn 
off  the  most  prominent  parts,  discovering 
to  view  the  copper  or  brass  beneath. 

The  only  metals  that  are  silvered  are 
copper,  brass,  and  very  rarely  iron. 

There  are  three  modes  of  silvering, 
namely,  by  silver  amalgam,  by  muriated 
silver,  and  by  silver  in  substance. 

Silvering  by  amalgamation  is  thus  per- 
formed : 

To  a  solution  of  nitrated  silver  add 
some  plates  of  copper,  which  will  throw 
down  the  silver  in  its  metallic  state,  and 
very  finely  divided;  scrape  it  from  the 
surface  of  the  copper,  wash  it  well,  and 
dry  it.  Of  this  powder  take  half 'an  ounce, 
of  common  salt,  and  sal  ammoniac  two 
ounces,  and  of  corrosive  sublimate  one 
drachm  :  rub  them  well  together,  and 
make  them  into  a  paste  with  a  little  wa- 
ter. Then  take  the  vessel  to  be  silvered, 
and  clean  it  by  means  of  a  little  very  di- 
lute aquafortis,  or  by  scouring  it  with  a 
mixture  of  common  salt  and  tartar.  When 
it  is  perfectly  clean,  rub  it  with  the  above- 
mentioned  paste  till  it  is  entirely  covered 
with  a  white  metallic  coating ;  this  coat- 
ing is  an  amalgam  produced  by  the  de- 
composition of  the  corrosive  sublimate  by 
means  of  the  copper,  to  the  surface  of 
which  it  applies  very  closely  and  expedi- 
tiously. The  copper  being  thus  silvered 
over  is  to  be  washed,  dried,  and  after- 
wards heated  nearly  red,  in  order  to  drive 
off  the  mercury ;  the  silver  remains  be- 
hind adhering  firmly  to  the  copper,  and 
capable  of  being  highly  polished. 

Silvering  by  luna  cornea. 
Prepare  the  luna  corner  in  the  usual 
manner,  by  pouring  solution  of  common 
salt  into  nitrat  of  silver  as  long  as  any 
precipitation  takes  place,  and  boiling  the 
mixture;  the  white  curdy  matter  thus 
obtained  is  to  be  mixed  with  three  parts 
of  good  pearl-ash,  one  part  of  washed 
whiting,  and  somewhat  more  than  one 
part  of  common  salt.  The  surface  of  the 
brass  being  cleared  from  scratches  is  to 
be  rubbed  with  a  piece  of  old  hat  and  rot- 
ten stone  to  remove  tmy  grease,  and  then 
is  to  be  moistened  wil.h  salt  and  water  i  a 


SIL 

little  of  the  composition  being  now  rub- 
bed on  with  the  finger,  the  surface  of  the 
metal  will  presently  be  covered  with  sil- 
ver. Then  wash  it  well,  rub  it  dry  with 
soft  rag;  and  as  the  coat  of  varnish  is  ex- 
tremely thin,  cover  it  with  transparent 
varnish  to  preserve  it  from  tarnish.  This 
kind  of  silvering  is  very  imperfect,  and  is 
only  used  for  the  faces  of  clocks,  the 
scales  of  barometers,  and  similar  objects. 

Silvering  by  Silver  in  Substance. 

There  are  three  ways  of  performing 
this.  The  first  is  by  mixing  together  20 
grs.  of  silver,  precipitated  by  copper,  2 
drachms  of  tartar,  2  drachms  of  common 
salt,  and  half  a  drachm  of  alum.  This 
composition  being  rubbed  on  a  perfectly 
clean  surface  of  copper  or  brass,  will  co- 
ver it  with  a  thin  coating  of  silver,  which 
may  afterwards  be  polished  with  a  piece 
of  soft  leather. 

A  still  better  way  is  that  which  is  call- 
ed French  plating,  which  consists  in  bur- 
nishing down  upon  the  surface  of  the  cop- 
per successive  layers  of  leaf-silver  to  any 
required  thickness.  In  this  the  silver  lias 
much  more  solidity  than  in  any  of  the  for- 
mer, but  the  process  is  tedious,  and  the 
junctures  of  the  leaves  of  silver  cannot  al 
ways  be  entirely  concealed. 

The  method  of  plating  (in  those  work* 
to  which  it  is  applicable)  which  appear 
to  be  the  best  of  all,  is  thus  performed  : 
one  of  the  surfaces  of  an  ingot  of  copper 
is  rendered  quite  smooth  and  clean,  ami 
is  sprinkled  over  with  glass  of  borax  ; 
upon  this  is  laid  a  plate  of  fine  silver, 
about  one-twelfth  of  the  weight  of  the 
copper,  and  the  two  are  carefully  bound 
together  by  wire;  the  mass  is  now  ex- 
posed to  a  full  red  heat,  which  melts  th< 
borax  and  causes  the  silver  to  adhere  to 
the  copper;  the  ingot  is  now  passed 
through  a  rolling  press,  and  formed  into 
a  plate;  both  the  silver  and  copper  ex 
tending  uniformly  during  the  whole  pro 
cess,  at  the  conclusion  of  which  the  two 
metals  are  inseparably  fixed  to  each  other 
See  Plating. 

Copper  may  be  silvered  over  by  rub 
bing  it  with  the  following  powder  :  Two 
drachms  of  tartar,  the  same  quantity  of 
common  salt,  and  half  a  drachm  of  alum, 
are  mixed  with  fifteen  or  twenty  grains 
of  silver,  precipitated  from  nitric  acid  by 
copper.  The  surface  of  the  copper  be- 
comes white  when  rubbed  witti^his  pow- 
der, which  may  afterwards  be  Drushed 
off,  and  polished  with  leather. 

The  sadlers  and  harness-makers,  cover 
their  wares  with  tin  for  ordinary  uses,  bu; 
a  cheap  silvering  is  used  for  this  purpose 
as  follows  :  Half  an  ounce  of  silver,  that 


SLA 


SLA 


rlas  been  precipitated  from  aqua  fprtis  by 
the  addition  of  copper,  common  salt,  and 
muriat  of  ammonia,ofeach  two  ounces,and 
one  drachm  of  corrosive  muriat  of  mer- 
cury, are  triturated  together,  and  made 
into  a  paste  with  water ;  with  this,  cop- 
per utensils  of  every  kind,  that  have  been 
previously  boiled  with  tartar  and  alum, 
are  rubbed,  after  which  they  are  made 
red  hot,  and  then  polished.  The  inten- 
tion of  this  process  appears  to  be  little 
more  than  to  apply  the  silver,  in  a  state  of 
minute  division  to  the  clean  surface  of  the 
copper,  and  afterwards  to  fix  it  there  by 
fusion  ;  and  accordingly  this  silvering 
may  be  effected,  by  using  the  argentine 
precipitate  here  mentioned,  with  borax 
or  mercury,  and  causing  it  to. adhere  by 
fusion. 

The  silvering  of  pins  is  effected,  by 
boiling  them  with  tin  filings  and  tartar. 
The  explanation  of  this  effect  is  difficult. 
It  should  seem  as  if  the  order  of  the  affi- 
nities was  changed,  by  the  increase  of 
temperature ;  so  that  the  tin  may  be  taken 
up,  at  a  lower  temperature  by  the  acid, 
and  give  place  to  the  brass  at  a  greater 
heat.    See  Tinning. 

SILVERING  OF  GLASS.  To  silver 
glass  globes  :  Takehalf  an  ounce  off  clean 
lead,  and  melt  it  with  an  equal  weight  of 
pure  tin  ;  then  immediately  add  half  an 
ounce  of  bismuth,  and  carefully  skim  off' 
the  dross  ;  remove  the  mixture  from  the 
fire,  and  before  it  grows  cold,  add  five 
ounces  of  mercury,  and  stir  the  whole 
well  together :  then  put  the  fluid  amal- 
gam into  a  clean  glass,  and  it  is  fit  for 
use. 

When  this  amalgam  is  used  for  foiling 
or  silvering,  let  it  first  be  strained  through 
a  linen  rag;  then  gently  pour  some  oun- 
ces thereof  into  the  globe,  intended  to  be 
foiled;  the  mixture  should  be  poured 
into  the  globe,  by  means  of  a  glass  or 
paper  funnel,  reaching  almost  to  the  bot- 
tom of  the  globe,  to  prevent  its  splashing 
to  the  sides ;  the  globe  should  then  be 
dexterously  inclined  every  way,  though 
very  slowly,  in  order  to  fasten  the  silver- 
ing :  when  this  is  once  done,  let  the  globe 
•  est  some  hours  ;  repeat  the  operation, 
till  at  length  the  fluid  mass  is  spread 
even,  and  fixed  over  the  whole  internal 
surface ;  as  it  may  be  known  to  be,  by 
viewing  the  globe  against  the  light :  the 
superfluous  amalgam  may  then  be  pour- 
ed out,  and.  the  outside  of  the  gjobe  clear- 
ed.  See*GLAss. 

SKIN.  For  the  preparation  of  the  skin 
of  animals,  for  the  purposes  of  manufac- 
ture, see  the  article  Leather. 

SLAG.  Is  a  technical  term  used  among 


smelters,  and  workers  in  minsrals,  to  ex- 
press any  hard  vitrescent,  generally  co- 
loured and  opake  mass  :  produced  by  the 
fusion  of  any  stony  or  metallic  mixture. 
It  generally  consists  of  the  gangue  or 
matrix  of  the  ore,  together  with  any  sa- 
line or  earthy  flux  that  may  have  been 
used.  Thus  the  slag  of  iron  founderies, 
is  for  the  most  part  composed  of  the  ear- 
thy part  of  the  ore,  of  the  lime  used  as  a 
flux,  and  the  whole  deeply  coloured,  with 
a  part  of  the  oxyd  of  iron,  which  has  es- 
caped reduction.  A  slag  differs  from  a 
scoria,  in  being  more  dense  and  more  com- 
pletely vitrehed,  whereas  the  scoria  or 
dross  is  lighter  and  porous.  'When  the 
slag  is  very  opake  and  heavy,  it  con- 
tains a  considerable  quantity  of  metallic 
oxyd,  so  that  in  improving  smelting  works, 
it  is  often  worth  while  to  work  over 
again,  with  fresh  reducing  matter,  the 
slags  of  former  operations  conducted  less 
skilfully.  In  some  parts  the  slag  of  foun- 
deries, is  broken  into  lumps,  and  used  for 
mending  roads,  for  which  it  makes  an  ex- 
cellent material  when  a  little  worn  down, 
being  very  hard,  and  impenetrable  by 
water. 

S1MILOR.    See  Copper. 

SIZK.    See  Gelatin. 

SLATE.  Slate  is  a  stone  of  a  compact 
texture,  and  laminated  structure,  splitting 
into  fine  plates. 

The  Whitish  Slate. 
Is  a  soft  friable  stone,  of  a  tolerable  fine 
and  close  texture,  considerably  heavy, 
perfectly  dull  and  destitute  of  brightness, 
variegated  with  a  pale  brown,  or  brown- 
ish yellow.  This  species  is  common  in 
many  countries,  lying  near  the  surface  of 
the  ground.  It  is  commonly  used  for  co- 
vering houses.  It  is  found  near  the  Le- 
high, Pennsylvania. 

The  Jlal  Slate. 
Is  of  a  very  fine,  elegant,  and  smooth 
surface,  considerably  heavy,  and  of  a  very 
beautiful  pale  purple,  glittering  all  over 
with  small  glossy  spjngies.  This  kind  of 
slate  is  much  valued,  as  a  strong  and 
beautiful  covering  for  houses. 

The  Common  Blue  Slate. 
Is  of  a  fine  smooth  texture  and  glossy 
surface,  moderately  heavy,  and  of  a  pale 
greyish  blue.  This  is  also  very  common, 
and  is  used  in  most  places  for  "the  cover- 
ing for  houses. 

The  Black  Slate. 
The  friable,ahiminous  black  slate,being 
the  Irish  slate  of  thf:  shops.   It  is  com- 


SMO 

mon  in  many  parts  of  Ireland,  and  is  also 
found  in  some  places  in  America.  There 
are  other  varieties  of*  slate. 

The  chief*  purpose  to  which  slates  are 
applied,  is  that  of  covering  houses  ;  for 
which  it  furnishes  a  strong  and  elegant 
root".  As  the  usual  method  of  slating  bus, 
from  experience,  not  proved  sufficiently 
durable,  Mr.  Richard  Elliott  obtained  a 
patent  in  March,  1781,  for  a  mode  of  co- 
vering houses,  &c.  on  a  more  safe  and 
eligible  plan,  than  that  generally  followed, 
ilis  practice  consists,  in  cutting  the  slates 
in  a  rhomboidal  form,  so  as  to  fold  over 
each  other.  These  are  next  laid  in  lime 
or  putty,  and  fastened  to  the  rafters,  on 
boards,  by  means  of  nails  or  screws,  either 
of  wood  or  ivon.  This  patent  is  now  ex- 
pired ;  and  as  Mr.  Elliott's  method  pro- 
mises to  secure  houses,  covered  with  this 
fossil,  more  effectually  from  the  effects  of 
rain  and  moisture,  than  the  common  plan, 
we  recommend  the  former  to  the  atten- 
tion of  our  readers;  referring  such  as  may 
wish  for  a  more  distinct  idea  of  his  prac- 
tice, to  the  12th  volume  of  the  Repertory 
of  Arts  ;  where  it  is  fully  described,  and 
illustrated  with  an  engraving. 

SMELTING  OF  ORE.    See  Ore. 

SMOKE,  a  fume  or  vapour,  disengaged 
in  the  act  of  combustion.  The  curing  of 
smoky  chimneys,  or  fire  places,  or  the 
method  of  preventing  the  smoke  from 
passing  downwards,  may  be  seen  in  the 
article  on  Fire  Places. 

If  the  funnel  of  a  chimney,  says  Dr. 
Willich  be  too  short,  (which  is  necessarily 
the  case  in  low  building,  as  it  would  other- 
wise endanger  the  roof,)  it  will  be  advisa- 
ble to  contract  the  opening  of  the  chim- 
ney, so  as  to  compel  the  incumbent  air  to 
pass  through,  or  at  least  very  near  to  the 
fire.  Thus,  the  funnel  will  become  warm- 
ed :  and  the  confined  air  being  rarefied 
by  heat,  will  rise  upwards,  and  maintain 
a  proper  draught  at  the  orifice. 

Another  cause  of  chimnies  smoking, 
arises  from  the  injudicious  position  of  a 
door.  Hence,  if  the  door  and  chimney 
happen  to  be  on  the  same  side  of  the 
room,  and  the  former  should  open  against 
the  wall,  the  air  will  necessarily  pass  into 
the  chimney,  and  expel  the  smoke  into 
the  room.  This  inconvenience  will  be  felt 
particularly,  on  shutting  the  door ;  the 
current  being  then  considerably  increas- 
ed, to  the  great  annoyance  of  those  who 
may  be  near  the  fire.  Such  nuisance 
may  be  easily  prevented,  by  placing  a 
screen  from  the  wall  round  the  fire  place, 
so  as  to  intercept  the  air*  A  more  sim- 
ple method,  however,  is  that  of  changing 
the  hinges  of  the  door,  so  that  it  may  open 
the  contrary  way;  and  thus  occasion  a 


SNU 

current  of  air  to  circulate  along  the  oppo- 
site wall. 

Lastly,  the  chimnies  of  new  houses,  for 
want  of  sufficient  ventillation,  frequently 
smoke  to  such  a  degree,  as  to  render 
them  almost  uninhabitable.  To  remedy 
this  unpleasant  molestation,  it  has  been 
proposed  to  draw  down,  the  upper  sash 
of  a  window,  for  the  space  of  an  inch.  As 
the  frames,  however,  are  generally  fixed, 
especially  in  old  houses,  an  expedient  has 
been  adopted,  of  cutting  a  circular  hole, 
in  a  pane  of  glass,  and  substituting  a  round 
plate  of  tin,  suspended  on  an  axis,  and  di- 
vided into  vanes  ;  which,  being  severally 
bent  in  an  oblique  direction,  are  moved 
by  the  current  of  air ;  and  the  ventilator 
is  forced  round,  in  a  manner  similar  to  the 
sails  of  a  windmill.  This  contrivance  ge- 
nerally answers  the  end  proposed ;  but, 
as  the  continual  noise  is  very  troublesome, 
the  following  method  has  been  preferably 
devised.  It  simply  consists  in  taking  out 
a  pane  of  glass,  and  suspending  it  on  hin  - 
ges, so  as  to  be  opened  and  shut  at  plea- 
sure ;  or  the  pane  may  be  set  in  a  tin  frame, 
and  supported  by  two  moveable  joints  on 
each  side,  serving  the  purpose  of  letting 
it  down  or  drawing  up  and  shutting  it, 
according  to  circumstances,  having  pro  - 
per hinges  at  the  lower  part :  thus,  by- 
opening  such  a  pane,  to  a  greater  or  less 
distance,  the  necessary  supply  of  fresh  air 
may  be  admitted,  without  exposing  per- 
sons in  the  room,  to  the  draught. 

SMOKING,  in  domestic  economy,  is  a 
mode  of  preserving  meat,  such  as  hams, 
bacon,  geese,  &c.  by  previously  salting, 
and  then  exposing  "them  to  the  smoke, 
arising  from  a  wood  fire. 

A  fire  from  the  branches  of  the  juniper- 
tree,  imparts  to  the  flesh  of  animals  a  very 
agreeable,  pungent  flavour. 

Smoking  of  Lamps. 

Is  a  circumstance  frequently  diregard  • 
ed,  in  domestic  life.  Let  a  sponge,  three 
or  four  inches  in  diameter,  be  moistened 
with  pure  water,  and  in  that  state  be  sus- 
pended by  a  string  or  wire,  exactly  over 
the  flame  of  the  lamp,  at  the  distance  of 
a  few  inches  :  this  substance  will  absorb 
•all  the  smoke,  emitted  during  the  even- 
ing, or  night ;  when  it  should  be  rinced 
in  warm  water,  and  thus  again  rendered 
fit  for  use. 

SNUFF,  a  well  known  preparation  of 
tobacco,  with  sundry  odoriferous  or  other 
matters,  occasionally  added.  The  tobac- 
co is  reduced  to  powder,  and  the  othe" 
articles  are  afterwards  mixed  with  it. 

It  will  be  sufficient  to  say,  that  there 
are  three  classes  of  snuffs,  under  which 
all  the  rest  may  be  placed,  viz.    1.  Gra- 


\ 


SNU 

milated.  2.  An  impalpable  powder.  3. 
The  bran,  or  coarse  parts,  remaining  after 
the  second  sort  has  been  silted. 

Lord  Stanhope  has  made  a  calculation, 
of  the  time  wasted  by  professed  snufi- 
lakers,  which,  as  it  is  both  curious  and 
amusing,  shall  be  here  inserted. 

"  Every  professed,  inveterate,  and  in- 
curable snuff-taker,  (says  his  lordship,) 
at  a  moderate  computation,  takes  one 
pinch  in  ten  minutes.  Every  pinch,  with 
the  agreeable  ceremony,  of  blowing  and 
wiping  the  nose,  and  other  incidental  cir- 
cumstances, consumes  a  minute  and  a 
half.  One  minute  and  a  half  out  of  every 
ten,  allowing  sixteen  hours  to  a  snuff- 
taking  day,  amounts  to  two  hours  and 
twenty -four  minutes,  out  of  every  natural 
day ;  or  one  day  out  of  every  ten.  One 
day  out  of  every  ten,  amounts  to  thirty- 
•s'tx  days  and  a  half,  within  the  year.— 
Jlenceif  we  suppose  the  practice,  to  be 
persisted  in  forty  years,  two  entire  years 
of  the  snuff-taker's  life,  will  be  dedicated 
to  tickling  his  nose,  and  two  more  to  blow- 
ing it.  The  expense  of  snuff,  snuff-boxes, 
mid  handkerchiefs  are  not  here  insisted 
on,  though  they  would  make  a  separate 
essay  by  themselves  :  in  which  it  might 
be  made  to  appear,  that  this  luxury,  en- 
croaches as  much  on  the  income  of  the 
snuff-taker,  as  it  does  on  his  time  ;  and 
that  by  a  proper  application,  of  the 
time  and  money  thus  lost  to  the  pub- 
lic, a  fund  might  be  constituted  for  the 
discharge  of  the  national  debt." 

Whimsical,  however,  as  the  above  ob- 
servations undoubtedly  are,  yet  it  may  be 
ascertained,  that  the  snuff-taker,  is  by  no 
means  a  useless  member  of  society  ;  for, 
if  the  consumption  of  tobacco  be  duly  es- 
timated, and  the  wear  and  tear  of  appa- 
rel be  added  to  the  accompt,  something 
is  rather  gained  than  lost  by  the  public. 
Nor  will  the  individual  snuff-taker  be  in- 
jured ;  as  his  lordship  assumes  a  term  of 
forty  years,  to  his  reckoning,  as  if  life  were 
prolonged  by  the  operation. 

Hovi  to  perfume  Snuff  with  Flowers. 

The  tube-rose,  the  jessamine,  the 
orange -flower,  are  those  which  communi- 
cate the  more  easily  their  fragrancy  to 
the  snuff.  To  produce  this,  have  a  box 
lined  with  white  paper,  perfectly  dry,  in 
which  make  a  bed  of  snuff,  of  the  thick- 
ness of  an  inch  ;  then  one  of  flowers,  ano- 
ther of  snuff,  and  another  of  flowers  again; 
continuing  so  to  do,  till  you  have  employ  - 
ed  all  the  snuff.  After  having  let  this 
stratification  subsist  for  twenty -four  hours, 
separate  the  flowers  from  the  snuff,  by 


SNU 

means  of  the  sieve,  and  renew  the  sain? 
stratification  again,  as  before,  with  new 
flowers.  Continue  this,  till  you  find  that 
your  snuff  has  acquired  a  sufficient  fra- 
grancy from  the  flowers  :  then  put  it  into 
lead  boxes,  to  keep. 

Another  Way  to  do  the  same. 
There  are  people  who  make  the  strati- 
fication another  way.  They  inclose  their 
flowers  between  the  sheets  of  white  pa- 
per, filled  with  pin-holes  as  thick  as  pos. 
sible  ;  this  bed  they  lay  between  two  of 
snuff ;  and,  as  for  the  small  quantity, 
which  may  have  got  in  the  papers  through 
these  holes,  you  sift  it  out  by  means  of  a 
sheer,  horse-hair  sieve.  The  flowers  must 
be  renewed  four  or  five  times.  This  me- 
thod seems  the  less  troublesome  ;  and  the 
snuff  catches  the  odour  nearly  as  well. 

Another  Method. 
A  preparation  of  snuff  may  be  made  of 
an  excessive  nice  fragrancy,  with  buds  of 
roses.  The  process  is  this.  Rob  those 
buds  of  their  green  cup,  and  the  pistillum 
which  is  in  the  middle ;  instead  of  which 
last,  you  are  skilfully  to  introduce  a  clove, 
without damaging,and  breaking,or  loosen- 
ing the  rose-leaves,  which  are  closely 
wrapped  up  one  in  another.  Such  buds, 
thus  prepared,  put  into  a  glass  vessel  well 
covered  over  with  a  bladder,  and  a  leather 
besides,  and  expose  them  for  a  month  in 
the  sun  ;  after  which  term,  you  make  use 
of  these  buds  as  before  directed,  for  the 
other  flowers. 

Snuff of Miile-flcur. 
This  millefieur  snuff,  or  snuff  of  a 
thousand  flowers,  is  made  by  mixing  to- 
gether, a  number  of  odorous  flowers, 
managing  the  quantity  of  each  of  them, 
according  to  the  greater  or  less  degree 
of  fragrancy,  they  are  empowered  with, 
so  that  none  be  found  to  have  a  predomi- 
nancy over  the  others.  When  that  is  ex- 
ecuted, you  proceed,  as  before  directed, 
to  the  alternate  stratification  of  this  mix 
ture,  and  of  the  snuff-powder. 

Snuff,  after  the  Method  practised  at  Home. 

lake  the  snuff  after  being  perfumed 
with  flowers,  and  put  it  into  a  large  "bowl, 
or  other  proper  vessel.  Pour  over  it  some 
white  wine,  with  an  addition,  if  you  choose, 
of  essences  of  musk  and  amber,  or  any 
other  such  like  odours.  Then  stir  your 
snuff,  and  rub  it  between  your  hands.  In 
this  manner,  you  may  have  snuff  of  what- 
ever you  desire,  which,  to  distinguish 
from  each  other,  you  put  into  seperate 
lead  boxes,  with  a  particular  mark. 


SNU 


SOA 


77*  Snuff  with  the  Odour  of  Civet. 
Take  a  little  civet  in  your  hand  with  a 
little  snuff';  spread  that  civet,  more  and 
more,  by  bruising  it  with  your  fingers,  and 
an  addition  of  snuff  After  having  mixed 
and  re-mixed  it  thus  in  your  hand,  with 
the  whole  quantity  of  snuff,  put  all  again 
together  in  the  box  as  before.  You  may 
do  the  same  with  respect  to  other  odours. 

Amber -snuff. 
Pound  in  a  mortar,  twenty  grains  of 
amber,  adding  by  degrees  one  pound  of 
snuff  to  it,  which  you  handle,  rub,  and 
mix  afterwards  with  your  hands,  to  intro- 
duce the  odour  the  better  among  it. 

Snuff,  Malthese  fashion. 
Take  a  snuff  ready  prepared  with 
qpange  flower-water,  then  perfume  it  with 
amb-:i  ,a.swe  iiave  just  said  ;  after  wh.ch, 
will,  tefi  grains  of  civet,  which  pound 
with  a  little  sugar  in  a  mortar,  you  intro- 
duce again  your  snuff  by  degrees,  to  the 
quantity  of  one  pound  for  these  ten  grains, 
increasing  either  the  snuff  or  the  odours, 
in  the  same  proportion  to  each  other. 

1  he  true  Malthese  Method  of  preparing 

Snuff. 

Take  rose-tree  and  liquorice  roots, 
which  you  peel.  Reduce  them  into  pow- 
der a.ut  sift  it;  then  give  it  what  odour 
you  like,  adding  white  wine,  brandy  or 
spirn  of  wine,  and  mix  your  snuff  well 
with  this  Such  is  the  true  Malthese 
method  of  preparing  snuff. 

The  Spanish  method  of  preparing  perfum- 
ed Snuff. 

1.  Pound  in  a  small  mortar,  twenty 
grains  of  musk,  with  a  little  sugar.  Add 
by  degrees  as  much  as  one  pound  of  snuff 
to  it :  then  pound  ten  grains  of  civet,  and 
introduce  your  pound  of  musked  snuff  to 
it,  in  a  gradual  manner,  as  you  did  before, 
and  rub  all  together  between  your  hands. 

2.  The  Seville-snuft  is  the  same  with 
only  an  addition  of  twenty  grains  of  va- 
nilla, an  ingredient  which  enters  into  the 
composition  of  chocolate. 

3.  They  who  are  fond  of  a  milder  and 
sweeter  odour  in  their  snuff,  may  increase 
the  quantity  of  snuff  for  the  prescribed 
doses  of  odours,  or  diminish  the  doses  of 
odours  prescribed  for  the  quantity  of 
snuff  You  must  take  great  care  not  to 
let  odorous  snuff  be  uncovered  in  the  air, 
but  to  keep  it  very  close,  for  fear  it  should 
lose  its  fragrancy. 

4.  As  the  Spanish  snuff  is  excessively 
fine,  and  drawing  towards  a  reddish  hue, 
to  imitate  it  in  the  above  prescription,  you 
must  choose  fine  Holland,  well  purged, 

VOX,.  IT. 


reddened,  and  granulated ;  pound  and  sift 
it  through  a  very  fine  silk  sieve.  Then 
you  give  it  whatever  odour  you  like,  after 
having  purged  it  in  the  manner  we  pre- 
scribed in  this  chapter,  art.  2. 

5.  There  is  no  inconveniency  in  taking 
a  snuff  already  prepared  with  flowers,  to 
give  it  afterwards,  when  you  like,  an  odour, 
of  musk,  amber,  or  other  perfume.  On  the 
contrary,  such  a  snuff  is  the  readier  to 
take  the  other  odours,  and  preserve  them 
so  much  the  longer. 

SNOW.— The  effect  of  snow  in  fertiliz- 
ing  soils  has  long  been  an  acknowledged 
fact,  but  the  cause  of  this  property  has 
been  disputed ;  and  it  is  perhaps  still  to 
be  regretted,  that  it  has  never  yet  been, 
sufficiently  examined  by  chemical  analy- 
sis. Hassenfratz  has  lately  asserted,  that 
it  contains  a  large  quantity  of  air,  and  that 
this  air  has  a  large  proportion  of  oxigen. 
His  proofs  are,  that  infusion  of  litmus 
dropped  into  snow-water  gives  it  a  red- 
der tinge  than  it  does  distilled  wa>ei  ;  .~nd 
that  much  more  oxide  of  iron  is  precipi- 
tated by  it  from  a  solution  of  the  sulphat. 
Dr.  Carradori,  however,  observes,  that 
fish  soon  die  in  snow-water,  which  he  as- 
cribes to  its  want  of  oxigen :  and  that  it 
does  not  give  out  oxigen  gas,  when  ex- 
posed to  the  action  of  light. 

SOAP,  is  a  saline  compound,  formed 
from  fat  or  inflammable  bodies,  which, 
not  being  soluble  in  water  by  themselves, 
compose,  by  the  assistance  of  salts,  a  ho- 
mogeneous mass  soluble  in  water.  These 
substances  are  slippery  to  the  touch,  so- 
luble in  water  and  alcohol,  and  common- 
ly lather  and  froth  with  these  fluids,  up- 
on being  agitated  with  them ;  they  also 
render  several  other  substances  miscible 
with  water.  They  are  discriminated  from 
each  other,  not  only  by  the  various  salts, 
but  likewise  by  the  different  sorts  of  fat 
substances  employed  in  their  preparation. 
Similar  combinations  also  are  found  ready 
formed  in  nature,  though  these  are  less 
in  use  and  require  to  be  adapted  by  art 
to  the  different  purposes  to  which  they 
may  be  applied. 

Different  vegetables  very  evidently  ex- 
hibit by  nature  a  saponaceous  quality  in 
their  composition,  of  which  soap-wort, 
the  soap  berry  tree  (sapindus  saponaria) 
and  the  common  nightshade,  may  be  ad- 
duced as  instances.  Now  since  the  pe- 
riod that  we  have  been  convinced  of  the 
presence  of  alk  tline  salts  in  vegetables, 
nothing  is  easier  than  to  conceive  the  ori- 
gin of  a  mixture  of  this  kind.  In  propor- 
tion, therefore,  as  this  salt  and  the  oily 
parts  exceed  the  rest  in  quantity,  and  the 
force  of  the  alkali  is  not  weakened  at  the 
same  time  by  the  presence  of  an  acid  . 


SOA 


SOA 


such  vegetable  will  be  more  or  less  of  a 
saponaceous  nature.  Sometimes  also, 
though  more  rarely,  a  saponaceous  com- 
pound is  met  with  in  vegetables,  which 
consists  of  oleaginous  particles  and  an 
acid.  For  this  reason  it  is  necessary  in 
every  case,  previous  to  attempting  to 
ascertain  the  composition  of  one  of  these 
compounds,  to  see  of  what  kind  it  is. 
With  this  view,  the  watery  extract  of  the 
saponaceous  plant  needs  only  to  be  mixed 
with  a  solution  of  fixed  alkaline  salt,  and 
notice  taken,  whether  any  precipitation  or 
separation  of  the  constituent  parts  ensue 
or  not.  If  in  this  operation  the  mixture 
be  not  observed  to  become  turbid,  but 
that  an  acid,  on  being  added  to  it,  pro- 
duces this  effect,  it  may  reasonably  be 
inferred,  that  this  saponaceous  compound 
has  an  alkaline  salt  for  its  basis.  But  if 
upon  the  addition  of  an  acid  to  such  ex- 
tract no  alteration  ensues,  and  it  is,  on  the 
contrary,  rendered  turbid  by  an  alkali,  it 
may  be"  concluded,  that  the  composition 
is  saponaceous  with  an  acid  basis. 

A  perfect  soap  cannot  be  produced  by 
art  with  acids.  From  the  commixture  of 
fluid  acids  and  oily  substances  no  other 
than  greasy,  saponaceous  masses  are  pro- 
duced ;  which,  though  they  are  miscible 
with  water,  cannot  be  brought  into  a  solid 
and  concrete  state,  and  at  the  same  time 
preserve  their  saponaceous  qualities. 

The  alkaline  salts,  on  the  contrary,  are 
intermediate  substances,  by  which  all  ole- 
aginous or  other  inflammable  bodies  may 
be  brought  into  a  perfectly  saponaceous 
state.  But  in  order  to  promote  the  com- 
bination proposed,  they  must  necessarily 
be  deprived  of  carbonic  acid,  by  boiling 
with  quicklime. 

We  shall  first  mention  some  of  the  sub- 
stances used  in  the  art,  and  the  articles 
from  which  some  of  them  are  obtained. 

Barilla,  or  barillia,  the  name  of  a  plant 
cultivated  in  Spain  for  its  ashes,  from 
which  the  purest  kinds  of  alkali  are  ob- 
tained. 

There  are  four  plants  which,  in  the 
early  part  of  their  growth,  bear  so  strong 
a  resemblance  to  each  other,  as  would 
deceive  any  but  the  farmers  and  nice  ob- 
servers. These  four  are,  barilla,  gazul, 
(or,  as  some  call  it,  algazul)  soza,  and  sa- 
licornia,  or  salicor.  They  are  all  burnt 
to  ashes,  but  applied  to  different  uses,  as 
being  possessed  of  different  qualities. 

Gazul  bears  the  greatest  affinity  to  ba- 
rilla, both  in  quality  and  appearance.  The 
principal  difference  consists  in  its  grow- 
ing on  a  still  dryer,  Salter  earth,  conse- 
quently it  is  impregnated  with  a  stronger 
salt. 

Soza,  when  of  the  same  size,  has  the 


same  appearance  as  gazul,  but  in  time 
grows  much  larger,  as  its  natural  soil  is  a 
strong  salt  marsh,  where  it  is  to  be  found 
in  large  tufts  of  sprigs,  treble  the  sixe  of 
barilla,  and  of  a  bright  green  colour,  which 
it  retains  to  the  last. 

Salicor  has  a  stalk  of  a  deep  green  co- 
lour, inclining  to  red,  which  last  becomes 
by  degrees  the  colour  of  the  whole  plant. 

Barilla  affords  less  salt  than  the  others. 
When  burnt,  it  runs  into  a  mass  resem- 
bling a  spongy  stone,  with  a  faint  cast  of 
blue. 

Gazul,  after  burning,  comes  as  near  ba- 
rilla in  its  outward  appearance,  as  it  does 
when  growing  in  its  vegetable  form ;  but, 
if  broken,  the  inside  is  of  a  deeper  and 
more  glossy  blue.  Soza  and  Salicor  are 
darker,  and  almost  black  within,  of  a  hea- 
vier consistence,  and  very  little  or  no  sign 
of  sponginess. 

All  these  ashes  contain  a  strong  alkali, 
but  barilla  the  best  and  purest,  though 
not  in  the  greatest  quantity.  Upon  this 
principle,  it  is  fittest  for  making  glass,  and 
bleaching  linen.  The  others  are  used  in 
making  soap. 

The  method  used  in  making  barilla  is 
the  same  as  that  of  burning  kelp. 

The  plant,  as  soon  as  ripe,  is  plucked 
up,  and  laid  in  heaps,  then  set  on  fire  ;  the 
salt  juices  run  out  below  into  a  hole  made 
in  the  ground,  where  they  collect  into  a 
vitrified  lump,  which  is  left  about  a  fort- 
night to  cool.  An  acre  may  give  about  a 
ton. 

American  Pot-ash, 
Is  a  fixed  vegetable  alkali,  another  va- 
luable material  in  hard  soap-making,  pre- 
pared from  the  ashes  of  burnt  wood  in 
America,  Russia,  &c.  For  the  process  of 
preparation,  see  Potash. 

Having  mentioned  a  few  of  the  princi- 
pal and  the  best  ashes  used  in  the  manu- 
facturing of  hard  soap,  we  shall  turn  our 
attention  to  the  mode  used  for  detecting 
sand  therein. 

This  fraud  is  but  too  frequently  prac- 
tised, not  only  by  kelp-hurners,  but  baril- 
la-makers also  ;  "that  is,  mixing  sand  with 
their  commodity  while  manufacturing,  and 
in  a  liquid  state. 

The  process  used  for  detecting  sand  is 
simple,  and  not  tedious,  viz  take  two 
ounces  of  a  fair  sample  from  any  parcel 
meant  to  be  purchased ;  beat  it  clown  in  a 
mortar  very  small,  pour  some  boiling  wa- 
ter upon  it,  and  rub  it  well  in  the  mor- 
tar ;  pour  off  this,  and  add  more,  and  so 
continue  until  all  the  black  light  substance 
is  gone  off  with  the  water.  The  sand  will 
then  be  found  in  the  bottom  of  the  mor- 
|  tar,  and,  if  surveyed  with  a  magnifier,  will 
I  resemble  in  appearance  small  pebble 


SOA 


SOA 


stones,  or  channel,  of  various  colours. 
l>ry  and  weigh  the  sand ;  and  from  the 
quantity  contained  in  the  two  ounces,  a 
calculation  may  be  made  for  the  hundred 
weight  or  ton. 

A  certain  given  quantity  of  water  ought 
always  to  be  allotted  for  trying  this  expo- 
ritnent ;  say,  one  or  two  pints :  and  by 
weighing  one  pint  thereof  afterwards, 
when  the  experiment  is  finished,  the  quan- 
tity of  alkaline  salt  may  also  be  discover- 
ed which  one  pint  of  said  ley  contains ; 
thus,  an  English  pint  of  spring  water 
Weighs  15  oz.  3  dps.  12  gr.— so  that  all 
above  that  weight  in  the  rubbing  water,  or 
ley,  must  be  supposed  alkaline  salt.  The 
price  of  the  article  ought  to  be  regulated 
according  as  the  experiment  turns  out. 

From  the  ashes  already  mentioned,  the 
strongest  and  purest  vegetable  alkali  is 
obtained  From  other  vegetables,  as  fern, 
broom,  bean-stalks,  8cc.  an  alkaline  salt 
is  produced,  but  so  impure,  and  in  such 
small  quantities,  that  no  soap-manufac- 
turer can  use  them  with  any  reasonable 
expectation  of  profit. 

The  other  ashes,  in  the  language  of  the 
soap-boiler,  are  the  following : 

Blue  Pearl-ashes. 
Half  a  pound  of  these  will  give  about 
5^  ounces  of  pure  potash  ; 

White  Pearl-fishes, 
Are  nearly  of  the  same  quality  with  the 
former,  half  a  pound  of  them  giving  five 
ounces  and  seven  drams  of  pure  alkali; 

Russia,  or  Jlfuscuvy  asfies, 
Have  very  much  the  appearance  of 
slacked  lime,  and  are,  like  it,  friable,  or 
mav  be  powdered  or  crumbled  betwixt 
the  fingers.  Half  a  pound  of  them  will 
only  give  about  ten  drams  and  fifteen 
grains  of  a  very  caustic  salt.  These  con- 
sist, therefore,  of  a  small  quantity  of  al- 
kaline sait,  united  with  a  large  quantity  of 
lime. 

Cashul  ashes, 
Are  of  the  colour  of  iron,  and  extreme- 
ly hard,  with  many  shining  particles  of 
charcoal  in  them  They  have  a  saline 
taste,  with  a  considerable  degree  of  pun- 
gency. Half  a  pound  of  these  ashes  be- 
ing boiled  in  a  quantity  of  water  for  twen- 
ty-four hours,  and  evaporated,  produced 
only  ten  drams  of  a  brown  salt,  having  a 
strong  caustic  alkaline  taste. 

JWarcoft  ashes, 
Are  of  a  paler  colour  than  the  former. 
Half  a  pound  of  them  dissolved  in  water, 
filtrated  and  evaporated,  yielded  only  ele- 


ven drams  one  scruple  and  two  grains  qt 
alkaline  residuum. 

A  boil  with  ihese  pearl-ashes,  after  the 
rosin  lias  been  melted,  is  peculiarly  ser- 
viceable for  killing  the  tallow,  (according 
to  the  common  phrase)  ;  it  converts  the 
whole  mass  in  the  pan  to  a  consistence,  or 
thin  weak  soap  But  this  will  be  better 
understood  when  we  come  to  the  opera- 
tion of  boiling  or  making  the  soap  ;  a  pro- 
cess which  we  shall  immediately  set 
about. 

Let  us  now  suppose  that  every  thing  if? 
ready  for  commencing  the  operation  upon 
a  moderate  scale,  viz.  that  there  is  a  small 
soap-pan,  capable  of  casting  from  20  to 
24  cwt.  of  soap,  six  or  eight  iron  vats,  or 
caves,  with  receivers  that  will  contain  12 
or  14  cwt.  of  kelp  or  ashes,  each  ;  that 
there  is  also  kelp,  ashes,  tallow,  lime- 
shells,  and  palm  oil,  at  hand.  These  are 
all  the  materials  necessary  for  performing 
the  operation,  and  finishing  a  pan,  or  ma- 
king of  hard  soap. 

The  first  thing  to  be  done  is,  to  prepare 
for  setting  a  cave,  viz.  Break  down  very 
small  about  12  cwt.  of  kelp,  and,  to  make 
a  good  ley,  2  or  3  cwt  of  American  pot- 
ash may  also  be  broke  and  mixed  there- 
with. Barilla  ash  is  generally  set  by  itself 
alone.  The  breaking,  however,  of  the 
American  potash,  from  the  danger  of 
sparks  (if  great  care  is  not  taken)  of  fly- 
ing into  the  eyes,  or  lodging  about  the 
feet,  &c.  would  be  as  well  altered  to  melt- 
ing down,  or  dissolving  in  boiling  water, 
and  then  poured  upon  the  other  materials 
(just  now  to  be  mentioned),  after  they 
are  put  into  the  cave. 

The  kelp  now  broke,  spread  about  one- 
sixth  part  of  it  upon  the  floor,  or  slake- 
pit,  if  there  is  one,  upon  which  lay  about 
half  a  bushel  of  lime,  and  water  it.  When 
it  begins  to  burst  and  crack,  put  on  ano- 
ther layer  of  kelp,  then  more  lime,  and 
water  them  ;  and  so  on,  stratum  super  stra- 
tum, or  one  above  the  other,  until  there  is 
about  the  quantity  of  2^  or  3  ash  barrels 
of  lime  mixed  with  12  cwt.  of  kelp.  Let 
this  stand  for  the  space  of  two  hours.  The 
cave  in  the  interim  may  be  got  ready  for 
receiving  them,  thus :  Lay  two  rows  of 
bricks  upon  the  bottom,  from  the  hole  or 
pipe  quite  across  to  the  opposite  side, 
forming  therewith  a  small  channel,  of 
three  or  four  inches  breadth.  Cover  this 
over  with  any  convenient  thing,  such  as 
slate,  tyle,  a  piece  of  dale,  &c.  And  to 
crown  the  whole,  lay  on  some  straw,  or 
an  old  bass  mat,  &c  This  is  to  prevent 
the  grosser  part  of  the  materials  from  get- 
ting-"in  and  stopping  up  the  channel,  in- 
tended only  for  the  leys  to  run  in.  Stop 
up  the  pipe,  or  hole  in  the  cave,  with  p> 


SUA 


SOA 


pin,  about  which  ought  to  be  lapped  a 
piece  of  paper  to  keep  all  close. 

The  preparations  now  accomplished, 
we  proceed  to  what  is  generally  termed, 

Setting  a  Cave- 
The  principal  object  here  to  be  observ- 
ed, is  to  mix  the  compound  well  together, 
previous  to  putting  into  the  cave.  The 
first  bucket  or  two  should  be  very  gently 
laid  upon  the  covered  drain,  or  bottom  of 
the  cave.  This  will  secure  the  straw,  or 
mat,  from  being  disturbed  afterwards,  by 
throwing  in  the  rest  of  the  materials. 

Throw  on  two  or  three  pails  of  water, 
at  different  periods,  during  the  setting, 
which  will  have  the  effect  to  dissolve  any 
small  particles  of  lime  that  may  formerly 
have  escaped  the  water.  Observe  always 
to  leave  a  vacancy  at  the  top  of  the  cave, 
of  about  eight  or  ten  inches  at  least,  in 
order  to  give  room  for  swelling  of  the 
lime,  and  filling  up  with  water. 

Supposing  now  the  kelp  and  lime  all 
put  into  the  cave,  and  no  ash  therewith, 
but  that  these  ashes  have  been  melted 
down,  or  dissolved  in  boiling  water,  and 
are  converted  into  ley  ;  pour  that  upon 
the  top  of  the  other  materials,  just  put 
into  the  cave,  and  fill  up  with  water,  un- 
til the  whole  is  completely  saturated 
therewith  ;  the  completion  of  which  will 
be  evident,  when  the  bubbling  in  the  cave 
ceases  to  arise.  Let  the  whole  now  stand 
for  12  or  14  hours,  adding,  however,  a 
little  more  water  as  the  stuff  appears  to 
dry  up,  or  absorb  that  already  put  on. 
When  the  cave  has  stood  the  above  time, 
loose  the  pin,  and  lei  the  ley  run  briskly 
off.  When  all  is  off,  stop  up  again,  and 
nil  with  water,  which  maj  stand  the  half 
of  the  former  time ;  the  pin  may  again  be 
loosed,  and  the  leys  allowed  to  run  gent 
ly  off,  keeping  the  cave  always  filled  up 
or  supplied  with  water.  It  may  be  un- 
necessary here  to  remark,  that  we  must 
hitherto  be  supposed,  as  laying  down  di 
rections  to  a  person  just  going  to  com 
mence  soap-making,  but  perfectly  igno- 
rant of  the  operation,  and  that  he  is  pre- 
paring every  necessary  agreeably  thereto 
In  that  case,  descending  to  particulars 
will,  we  hope,  be  excused  by  the  knowing, 
or  more"  experienced  reader. 

We  shall  now  go  on  by  informing,  that 
before  beginning  to  boil,  more  leys  must 
be  got  ready  ;  consequently,  another  cave 
may  be  prepared  in  the  same  manner  as 
the  former  one  ;  with  this  exception  only, 
that  instead  of  filling  up,  or  supplying  the 
second  cave  with  pure  water,  let  it  run 
through  the  former  cave  first,  and  then 
put  upon  the  second  The  intention  of 
ihis  is  obvious ;  that,  while  the  last  is  sup- 


plied with  water,  the  remaining  strengflb 
of  the  first  is  extracted,  and  collected  into 
the  second  :  and  this  must  be  the  uniform 
practice  at  all  times,  that  none  of  the  al- 
kali be  lost ;  never  turning  out  a  cave,  as 
spent,  until  you  discover  by  the  test,  the 
alkali  is  vanished. 

Having  just  mentioned  the  test,  we 
shall  take  this  opportunity  of  explaining 
what  it  is. 

It  is  prepared  in  the  following  manner  : 
Take  a  parcel  of  the  blue  flowers  of  any 
vegetables,  violets,  for  instance,  or  the 
blossom  of  the  mallow  ;  beat  them  with 
the  edge  of  a  knife,  and  squeeze  the  juice 
of  it  into  a  tea-cup  ;  with  a  small  brush, 
or  hair  pencil,  iay  over  a  sheet  of  white 
paper  with  this  juice,  and  when  dry  it  is 
fit  for  use.  All  alkalis  will  turn  it  green, 
and  all  acids  will  turn  it  of  a  red  colour. 
A  combination  of  them  both,  to  the  point 
of  saturation,  will  not  in  the  smallest  de- 
gree alter  the  colour  of  the  test,  because 
they  are  then  said  to  be  neutral,  having 
neither  the  properties  of  an  acid,  or  an 
alkali:  but  add  a  few  drops  mote,  of  ei- 
ther the  one  or  die  other,  the  effect  will 
be  evident.  If  alkali  is  added, « he  test 
wid  be  green  ;  if  acid,  it  will  be  red. 

An  intimate  acqu  dr  tance  with  every 
particular  relative  to  the  Ie\s,  is  the  one 
thing  needful  for  a  so: ip  boiler,  being  as  it 
were  the  ground-work  of  the  whole  ope- 
ration, and  material. \  i  tia]  to  be  v  ell 
understood,  before  any  attempt  ought  to 
be  made  at  soap-making 

We  come  now,  of  course,  to  examine 
the  leys  already  prepared,  and  to  deter- 
mine by  experiment,  whether  they  are,  or 
are  not,  fit  for  soap-making  ;  that  is,  whe- 
ther they  are  caustic  and  fit,  or  in  a  mild 
state,  consequently  unfit  for  the  pur- 
pose. 

Unless  a  soap-ley  be  rendered  caustic, 
or  deprived  of  its  fixed  air,  it  can  have  no 
union  with  vegetable  or  animal  substan- 
ces, such  as  oil,  tallow  or  grease  of  any 
kind,  so  as  to  convert  them  into  a  soap. 
For  the  sole  purpose,  therefore,  of  extract- 
ing the  fixed  air  from  the  leys,  di.  soap- 
makers  use  quicklime  Depriving  the 
mild  alkali  of  its  fixed  air,  renders  ii  caus- 
tic, or  of  a  burning,  corroding  quality,  and 
of  that  peculiar  nature,  that  instantly  at- 
tach themselves  to  ail  greasy  substances, 
and  converts  them  into  a  soap. 

The  common  vulgar  notion,  of  using 
quicklime  for  its  heat,  is  a  mistaken  idea, 
although  we  know  it  to  be  entertained  by 
many  soap-makers. 

A  mild  ley.  or  that  possessing  fixed  air, 
can  have  no  effect  upon  vegetable  or  ani- 
mal substances,  so  as  to  convert  them  into 
a  soap. 


SOA 


SOA 


Hence  we  may  perceive  the  pernicious 
practices  of  some  soap-boilers,  namely, 
melting  down,  or  dissolving  potash  in  boil- 
ing water,  and  in  that  mild  and  improper 
state,  adding  those  leys  to  the  boiler. 

Such  consummate  ignorance  persever- 
ed in,  must,  and  always  have  proved  ul- 
timate ruin  to  the  person  himself,  or  his 
unfortunate  employer. 

To  deter mine,therefore  the  proper  state 
of  the  ley,  take  a  quantity  in  a  glass,  or 
tea-cup,  drop  therein  ajfew  drops  of  sul- 
phuric acid,  or  oil  of  vitriol ;  if  this  causes 
an  effervescence,  or  Sfning  fermenta- 
tion in  the  ley,  the  fij^l  air  is  not  fully 
extracted ;  but  if  no  such  appearance  en- 
sue upon  the  combination  of  the  acid  and 
alkali,  the  ley  is  fit  for  immediate  use, 
being  arrived  at  the  state  of  a  proper 
caustic  soap-ley. 

A  soap-ley,  by  being  long  exposed  in 
open  vessels,  will  lose  lite  whole  of  its 
causticity,  and  seem  entMfctt  restored  to 
the  state  of  an  ordinary  fij^Mlkali.  The 
keeping  them  as  close  as  possible,  there- 
fore, appears  exceedingly  necessary. 

By  means  of  the  acid,  may  be  discover- 
ed also  the  comparative  strength,  between 
one  ley  and  another,  and  so  ascertain, 
which  of  the  two  contains  the  greatest 
quantity  of  fixed  alkaline  salt.  Thus, 
take  a  specific  quantity  of  each  ;  a  wine 
glassful,  for  instance  ;  drop  therein  a  do- 
zen diops,  or  so,  of  acid;  stir  with  a  bit 
of  stick,  and  apply  a  slip  of  the  test-paper. 
If  it  appear  green,  more  acid  must  be 
added,  and  stirred  again.  Applying  the 
test  a  second  time,  if  still  green,  a  few 
more  drops  must  be  added ;  and  so  con- 
tinue, until  you  find  the  paper  is  by  no 
means  altered  in  the  colour,  neither  green 
jior  red.  The  ley  is  then  neither  an  acid 
nor  an  alkali,  but  neutral,  or  a  combina- 
tion of  both,  brought  to  the  point  of  sa- 
turation. A  few  drops  more  of  the  acid, 
would  occasion  the  test-paper  to  take  a 
red,  instead  of  a  green  colour,  which 
would  distinctly  show  the  power  of  the 
acid  to  prevail. 

Treating  in  this  manner  the  different 
leys,  then  counting  the  number  of  drops 
taken  to  neutralize  them,  the  strongest 
ley  will  be  discovered  to  be  that  which 
has  required  the  greatest  quantity  of  acid, 
to  overcome  the  power  of  the  alkali. 

Soap  leys  are  also  judged  of  by  their 
specific  gravity,  or  weight,  comparative 
to  water.  oz.  dr.gr. 

An  English  pint  of  spring  water 

weighs  about       .       .     .     15  3  12 

\  strong  soup-ley,  the  English 
pint  weighs  about       .     .     17  6  24 


The  difF.  between  the  two  is,       2  3  12 


— and  supposed  to  be  the  quantity  of  fix 
ed  alkaline  salt,  contained  in  one  pint  oi 
such  ley. 

A  most  accurate  and  easy  method  for 
ascertaining  the  strength  of  soap-leys  for, 
immediate  use,  is  as  follows,  viz. 

Take  a  small  bottle,  and  having  j^^^^^ 
it  with  water,  put  it  into  one  scakjnnd 
as  many  lead-shot  into  the  othe^as  will 
exactly  balance  it.  Suppose  l^p  is  re- 
quisite for  that  purpose.  Suppose,  again, 
that  the  bottle  and  water  just  weighsrou^|^r 
ounces;  this  is  throwing  it  into  128 parts; 
half  of  that  is  G4-128,  or  2  ounces  ;  halve 
it  again,  is  32-128  parts,  or  one  ounce; 
again,  is  16-128  parts,  or  8  drachms  ;  then 
into  8-128  parts,  or  4  drachms;  4-128 
parts,  or  2  drachms  ;  2-128  parts,  or  one 
drachm;  and  1-128  parts,  or  half  a  drachm, 
which  is  bringing  it  to  the  lowest  deno- 
mination. 

Get  proper  weights  made  for  each  of 
these  divisions ;  and  when  the  strength 
of  the  ley  at  any  time  is  required  to  be 
ascertained,  fill  the  bottle  and  put  it  into 
the  scale  :  into  the  opposite  one,  the  ba- 
lance of  water,  or  the  128  shot,  is  placed; 
and  as  ley  is  always  heavier  than  water, 
some  one  or  other  of  the  divisions  will  be 
wanted  to  balance  the  ley  :  therefore, 
whatever  division  may  answer  for  that 
purpose,  must  be  called  the  weight  of  the 
leys  ;  the  surplus  weight  above  that  of 
water  being  only  reckoned,  and  not  the 
whole  quantity :  For  instance,  if  the  bot- 
tle of  ley  take  the  division  weight  No.16, 
in  that  case  the  ley  is  16-128  parts  hea- 
vier than  water,  or  8  drachms,  reasonably 
supposed  to  be  alkaline  salt. 

Having  endeavoured  to  furnish  the  rea- 
der, with  a  tolerable  idea  of  the  prelimi- 
naries of  soap-making,  we  shall  now  pro- 
ceed to  what  we  consider  the  easiest  and 
most  simple  part  of  the  business,  the 
boiling  ;  although  by  the  ignorant  and 
unwary,  conceived  to  be  the  principal  re- 
quisite, and  containing  the  whole  mystery 
of  the  trade. 

The  leys  being  now  ready,  we  shall 
commence  with  a  boiling  of  brown  or 
yellow  soap.  For  this  purpose,  let  there 
be  weighed  10  cwt.  of  tallow,  and  about 
3  cwt.  of  rosin :  the  rosin  to  be  broke  in 
small  lumps.  In  the  first  place,  put  into 
the  boiler  about  150  or  200  gallons  of  leys 
(about  the  weight  of  16  oz.  4  dr.  48  gi . 
the  English  pint,  which  will  nearly  an- 
swer to  No.  32,  of  the  fore-mentioned  di- 
visions,) and  set  the  fire ;  then  add  tbe 
tallow  and  rosin.  This  done,  the  pan  is 
said  to  be  charged. 

A  good  fire  may  be  kept  up  until  all  is 
thoroughly  melted,  and  the  pan  brought 
to  boil ;  during  which  time  there  ought 


SOA 


^isdoi 

per  y 
letsu 


to  be  constant  stirring  with  the  paddle, 
to  prevent  the  rosin  settling  to  the  bot- 
tom. If' the  goods  or  materials  in  the  pan 
appear  to  swell  up,  damp  the  fire, which 
is^done  by  opening  the  furnace  door,  and 
wing  ashes  thereon,  (some  have  pro- 
'ampers,)  when  the  whole  will  boil  at 
_MML£j.    As  the  caustic  alkali  immedi- 
^^^^Hftps  to  the  tallow,  there  is  no  occa- 
a^^^^^Vong  boiling  ;  about  two  or  three 
hours  vnll  he  long  enough  :  the  fire  may 
^^P^tmbe  drawn,  and  the  pan  allowed  to 
Stand  four  or  six  hours,  when  the  weak 
leys  may  be  pumped  off,  and  fresh  ones 
added  for  a  second  boil.   It  may  be  neces- 
sary to  mention,  that  when  the  pan  is 
wished  to  be  cranned,  or  pumped  off 
sooner,  a  few  pails  of  cold  ley  must  be 
thrown  in,  a  lit  tle  after  the  fire  is  drawn 

Set  the  fire  again  for  second  boil,  and 
when  properly  a-boil,  two  or  three  hour 
may  be  sufficient  at  any  one  time  to  con 
tinue  the  boil :  the  strength  of  the  leys 
are  often  gone  before  that  period  arrives 
A  short  experience,  however,  with  atten 
tion,  will  perfectly  inform  any  sagacious 
person  with  regard  to  this  particular 

The  boilings  to  be  thus  continued  day 
after  day,  until  the  soap  becomes  thick 
and  of  a  strong  consistence.    Take  then 
a  little  upon  the  forefinger,  and  after  let- 
ting it  cool  a  few  seconds,  press  it  with 
the  thumb.    If  it  squeezes  into  a  thin 
hard  scale,  the  soap  is  fit,  or  ready  for 
finishing  :  if  otherwise  it  appears  greasy 
and  sticks  to  the  finger,  and  of  a  soft  con- 
sistence,  more  leys  must  be  added,  and 
if  that  does  not  harden  it,  another  boil 
must  be  given.    But,  in  consequence  of 
the  former  scaly-like  appearance,  give  the 
pan  a  good  hearty  boil,  and  draw  the  fire 
Cool  down  with  two  or  three  pails  of  leys, 
and  in  about  two  hours  thereafter  pump 
off  the  leys  ;  which  should  be  done  at  all 
times  as  clean  as  possible.    This  done, 
put  in  six  or  eight  pails  of  water  to  the 
boiler  (no  leys  at  finishing  being  used,) 
set  a  brisk  fire,  and  keep  constantly  stir- 
ring with  an  hand-stirrer  and  paddle  alter- 
nately, until  all  is  melted,  and  begin  to 
shew  an  appearance  something  like  thin 
honey    Take  now  a  little  from  a  boiling 
part,  upon  the  hand-board,  and  observe, 
when  held  up,  if  any  leys  run  clearly  from 
it :  if  they  do,  more  water  must  be  put  in, 
and  the  boil  continued,  &c-  If  it  be  wished 
of  a  beautiful  colour,  20  lbs.  of  palm  oil 
may  be  put  into  the  boiler. 

It  is  not  essential  to  employ  heat  in  pro- 
ducing a  good  soap,  for  the  union  between 
the  oil  and  alkali  will  be  perfect  by  a  suf- 
ficient length  of  time  of  digestion,  if  the 
ley  be  strong  enough.  Thus  a  very  pure 
soap  is  sometimes  made  for  medicinal  pur- 


poses in  the  following  way :  mix  in  a  mar* 

ble  mortar,  or  any  vessel  not  metallic,  any 
quantity  of  olive  oil  with  half  its  weight 
of  a  strong  ley  of  caustic  soda.  The  oil 
should  be  previously  im  lted  in  case  it  has 
become  clotted  by  age.  Stir  them  well  to- 
gether, and  they  will  immediately  unite 
into  a  thick  white  mass,  and  continue  the 
stirring  for  some  minutes  several  umes  a 
day  for  about  a  week,  or  till  the  soap  is 
stiff  enough  to  be  put  into  wooden  frames 
in  the  usual  wayg  Let  it  remain  m  the 
frames  for  three  or  four  days,  till  it  has 
considerably  haiAied,  and'then  cut  it  in 
slices,  and  expoSTit  to  a  free  current  of 
air  in  a  dry  room,  till  itia  complete.  This 
soap  has  at  first  a  very  strong  hxiual 
smell,  aud  a  violently  acrid  ta^te,  botn  of 
which  go  oh  by  exposure  to  the  air,  but 
it  takes  nearly  a  month  before  the  taste  is 
mild  or  merely  saponaceous 

lit  lore  we  djfrrn-e  die  manufacture  of 
the  other  kii^Kof  soap,  we  may  give  in  a 
tew  words  t^Rsults  of  a  series  of  valua- 
ble, and  apparently  accurate,  comparative 
experiments  on  the  soaps  made  with  soda 
and  a  variety  of  oily  substances,  which 
were  undertaken  by  Pelletier  and  his  col- 
leagues. The  quantity  of  the  oil)  sub- 
stance in  each  instance  was  o  lbs.  and  the 
method  pursued  was  nearly  that  which 
has  been  described  as  followed  in  the 
large  way. 

Olive  Oil. 

Three  lbs.  (avoirdupois)  of  this  oil  pro- 
duced 5  lbs.  of  pure  white  soap  in  that 
state  of  dryness  as  to  be  fit  for  sale.  After 
keeping  for  two  months,  it  lost  an  ounce 
more  in  weight,  and  was  then  quite  dry, 
hard,  and  of  an  agreeable  smell. 


Oil  of  Almonds. 
Three  lbs.  of  this  oil  gave  an  excellent 
soap  in  every  respect  equal  to  the  for- 
mer, but  after  two  months  weighing  only 
4^  lbs. 

Suet. 

The  animal  fats  are  much  less  used  in 
France  for  soap-making  than  in  England, 
but  the  soap  which  they  give  is  in  every 
espect  as  good  as  that  from  olive  oil. 
The  precaution  used  in  oil  soap-making 
of  emplo\  ing  die  weaker  ley  at  first,  and 
gradually  proceeding  to  the  stronger,  was 
not  found  necessary  in  this  case.  Three 
lbs.  of  suet  gave  5  lbs.  of  perfectly  hard 
soap,  aftei  keeping  three  months  and  a 
half  in  a  dry  place. 

Lard. 
ird  ga^ 

dry  hard  soap,  after  keeping  for  three 
months.  In  this  and  the  former  experi* 
ment,  the  spent  ley  which  separated  from 


SOA 


SOA 


the  soap,  contained  a  quantity  of  animal 
gelatine. 

Rancid  Butter. 
A  quantity  of  stale  salt  butter  was  boil- 
ed with  water  to  extract  the  salt,  after 
which  S  lbs.  of  it  were  weighed  out  andl 
treated  with  soda  in  the  usual  manner. : 
From  the  above  quantity  a  white  soap  j 
was"  obtained  with  ease,  which  the  day  at-  i 
ter  it  was  made  weighed  11  lbs.  and  still ! 
retained  some  of  the  bad  smell  of  the  but-  \ 
ter,  and  on  keeping  for  two  months  it  still 
weighed  7  lbs. 

Horse  Oil. 
A  good  deal  of  grease  is  prepared  near 
Paris  from  horse  flesh,  by  boiling.  Of 
this,  3  lbs.  gave  5  lbs.  of  good  hard  soap 
without  any  unpleasant  smell,  alter  keep- 
ing for  two  months. 

Coleseed  Oil. 

Coleseed,  hempseed,  linseed,  rape,  and 
many  other  common  vegetable  oils,  have 
a  strong  unpleasant  smell  and  taste,  so  as 
not  to  be  used  in  food,  but  they  are  em- 
ployed largely  in  the  state  of  oil  for  seve- 
ral purposes  of  manufacture.  In  general 
they  are  not  much  used  for  the  hard  soaps 
with  soda,  but  a  good  deal  of  soft  soap  is 
made  of  them  in  Flanders  and  Holland, 
with  pearl-ashes,  as  will  be  presently  men- 
tioned. In  the  above  experiments  they 
gave  the  following  results  : 

Three  lbs.  of  coleseed  oil,  treated  as 
above,  with  soda,  gave,  on  coming  out  of 
the  frame,  only  5  lbs.  of  soap,  which  was 
yellowish  gray,  and  still  smelled  strongly 
of  the  oil.  On  keeping  for  three  months, 
it  was  reduced  to  3  lbs.  12  oz.  and  was  to- 
lerably hard,  but  by  no  means  equal  in 
this  respect  to  olive  oil,  kept  the  same 
length  of  time. 

Rape  Oil. 

Three  pounds  of  this  oil  gave  also  a 
yellowish  gray  soap,  which  after  keeping 
for  three  months,  gave  4^  lbs.  of  a  good 
soap,  sufficiently  hard. 

Beech-Mast  Oil. 
Three  pounds  of  this  oil  gave  a  gray 
strong  smelling  soap,  which,  after  three 
months,  weighed  4  lbs.  10  oz.,  and  was 
still  pasty,  and  stuck  to  the  fingers.  This 
oil,  therefore,  can  only  be  used  in  mixture 
With  others  that  give  a  harder  soap. 

Htmp-seed  Oil. 
This  is  one  of  the  most  valued  oils  for 
the  soft  soaps,  but  will  not  answer  for  the 
hard.  Three  pounds  gave,  after  due  boil- 
ing, a  green  soft  saponaceous  mass,  which 
became  pasty  on  any  addition  of  water. 


After  two  monfhs  it  weighed  4J  lbs.,  and. 
hardened  a  little,  but  not  sufficiently  to 
be  used  in  common  washing. 

Linseed  Oil. 
Three  pounds  of  this  gave  5  lbs.  of 
soap  on  coming  out  of  the  frames,  which 
was  greasy,  pasty,  and  adhesive,  with  a 
very  strong  smell,  and  softened  speedily 
on  any  addition  of  water.  In  two  months 
it  lost  half  a  pound  of  its  weight,  but  re- 
mained pasty  and  adhesive. 

Whale  Oil. 

This,  and  other  kinds  offish  oil,  unites 
sufficiently  well  with  soda,  and  forms  a 
deep  red-brown  soap  of  tolerably  hard 
consistence ;  but  this  soap  has  the  incon- 
veniences of  long  retaining  the  offensive 
smell  of  the  oil,  and  being  too  readily 
softened  by  water,  which  unfit  it  for  do- 
mestic purposes,  though  it  may  be  used 
in  bleacheries,  &c.  where  the  smell  may 
be  dissipated  by  long  exposure  to  the  air. 
Three  pounds  of  this  oil  gave  4£  lbs.  of 
soap,  after  keeping  for  two  months.  Ling' 
and  seal  oil  soap  have  nearly  the  same 
properties  and  inconveniences. 

All  the  above  experiments  were  repeat- 
ed with  the  crystallized  carbonat  of  soda, 
instead  of  the  barilla  of  commerce,  which 
was  employed  in  the  first  set  of  experi- 
ments, and  the  respective  results  so  near- 
ly agreed  with  the  former,  that  a  particu- 
lar enumeration  of  them  is  needless.  In 
these  latter  3  lbs.  of  carbonat  of  soda,  ren- 
dered caustic  by  1  lb.  of  lime,  were  used 
for  3  lbs.  of  the  oil ;  but  in  manufacturing 
in  the  large  way,  the  experimenters  con- 
ceive that  80  parts  of  the  alkali  would  be 
sufficient  for  100  of  the  oil. 

With  the  fixed  alkaline  salts,  soda  as 
well  as  pot-ash,  tallow-soaps  are  prepar- 
ed in  the  following  manner :  One  part  of 
either  of  these  alkaline  salts,  and  about 
two  parts  of  quick-lime,  as  much  as  is  re- 
quisite to  render  them  perfectly  pure,  are 
to  be  mixed  together,  and  made  into  a 
strong  ley,  with  the  necessary  quantity  of 
water.  This  ley  is  then  made  to  boil  with 
three  parts  of  tallow  or  fat  over  a  gentle 
fire,  and  kept  continually  stirring  till  the 
mixture  becomes  thick,  and  ceases  to  ad- 
here to  the  hand,  when  a  little  is  taken 
out  of  it  for  a  sample.  Toward  the  end, 
a  proportional  quantity  of  common  salt  is 
added,  by  which  the  soap  acquires  a  great- 
er degree  of  hardness.  This  effect  has 
been  accounted  for  on  various  supposi- 
tions. It  has  been  said,  that  the  quanti- 
ty of  water  present  is  diminished  by  the 
abstraction  of  as  much  as  the  salt  re- 
quires for  its  solution ;  a  circumstance 
probably  of  little  consequence.  Again. 


/ 


SOA 


SOA 


the  soap  is  rendered  less  soluble  in  the 
water  by  this  addition 
more  readily  separates, 
important  effect  seems  to  be,  that  the  mu- 
riatic acid  of  the  salt  attracts  the  potash 
of  the  soap,  and  gives  its  own  soda  in  re- 
turn, which  is  known  to  afford  a  much 
harder  soap.  The  weight  of  the  soap 
here  acquired  is  commonly,  as  Wiegleb 
says,  double  that  of  the  tallow  employed 
in  making  it.  In  the  same  manner  a  wax 
soap  may  be  prepared  either  of  yellow  or 
white  wax,  which  is  about  three  times  the 
weight  of  the  wax,  is  very  hard  and  firm, 
and  has  an  agreeable  smell  of  almonds. 
The  Gravenhorts  in  Brunswick  likewise 
prepare  a  soap  of  cocoa  butter  for  medi- 
cal uses  Spermaceti  also  m..y  be  made 
into  soap  with  a  caustic  lixivium. 

Macqucr  gives  us  the  following  pro- 
cess for  oil  soap  :  One  part  of  quicklime 
and  two  parts  of  good  Spanish  soda  are 
boiled  together  during  a  short  time,  with 
twelve  times  as  much  water,  in  an  iron 


Close  attention,  therefore,  is  absolute!-/ 
and  therefore  |  needful  upon  this  first  boil ;  which  may 
But  the  most '  be  continued  about  two  hours,  with  a  mo- 
derate fire,  when  it  may  be  drawn  away, 
and  the  pan  allowed  to  settle  about  two 
hours,  when  the  ley  may  be  drawn  off. 
The  process  to  be  observed  in  this  soap 
is  exactly  similar  to  the  last  operation. 
Two  or  three  boils  a  day  to  white  soap 
may  be  given  with  great  ease ;  the  ley 
sooner  subsiding  in  the  boiler  than  with 
yellow  soap,  and  can  be  cleaner  pumped 
off. 

When  sufficient  boils  have  been  given, 
and  the  soap  is  arrived  at  perfection,  it 
will  assume  an  appearance  something  like 
a  curdy  mass.  Take  then  a  little  upon 
your  forefinger  (as  before  directed)  ;  and 
if  the  same  effect  seem  to  attend  it,  that 
is,  when  pressed  with  the  thumb  it  sqeeze 
into  a  thin,  hard,  clear  scale,  and  part 
freely  from  the  finger ,  the  soap  is  ready 
for  finishing.  Draw  the  fire  cool  down 
with  a  few  pails  of  ley,  and  in  a  short  time 


cauldron.    This  lixivium  is  to  be  filtered,  I  thereafter  pump  clean  off. 
and  evaporated  by  heat,  till  a  phial,  which  j    Set  the  fire,  and  add  to  the  soap  eight 


is  capable  of  containing  an  ounce  of  wa 
ter,  shall  contain  an  ounce  and  three 
eighths  of  this  concentrated  lixivium. 
One  part  of  this  lixivium  is  to  be  mixed 
with  two  parts  of  oil  of  olives,  or  of  sweet 
almonds,  in  a  glass  or  stone-ware  vessel. 


or  ten  pails  of  water  (the  pail  we  suppose 
to  contain  about  nine  or  ten  English  gal- 
lons). When  this  is  melted,  and  properly 
incorporated  with  the  soap,  try,  as  for- 
merly directed,  if  the  ley  run  from  it 
when  held  up  upon  the  hand-board.  If  it 


The  mixture  is  to  be  stirred  from  time  to  j  do,  more  water  must  be  put  in.  If  it  do 
time  with  an  iron  spatula,  or  with  a  pes-  j  not  run,  or  there  Ibe  no  appearance  of  it, 
tie,  and  it  soon  becomes  thick  and  white.  :  continue  boiling  for  a  short  time  longer, 
The  combination  is  gradually  completed,  j  and  then  add  a  pail  of  salt  and  water 
and  in  seven  or  eight  days  a  very  white  i  pretty  strong,  mixed  together ;  about  one 

'  third  salt,  and  two  thirds  water  This 
will  have  the  effect  of  cutting  up  the  pan, 
or  separating  the  soap  and  water  com- 


and  firm  soap  is  obtained. 

For  the  coarser  sorts  of  soap  cheaper 
oils  are  employed,  such  as  oil  of  nuts,  lin- 


seed, hempsetd,  fish,  &c.  Either  of  these  .  pletely  from  one  another.  When  this  is 
kinds  of  soap,  to  be  good,  must  neither  j  apparent,  draw  the  fire ;  let  it  stand  for 
feel  greasy  or  unctuous  in  water,  nor  ex-  ,  half  an  hour,  when  the  water  will  pump 
hibit  any  vestige  of  fat  upon  the  water.  '■  off,  bringing  therewith  most  of  the  re- 
It  ought  farther  to  dissolve  easily  in  water,  j  maining  alkaline  ley  of  the  former  boil, 
and  lather  well,  as  likewise  be  easily  so- !  This  I  call  the  first  washing;  and  if 
luble  in  alcohol.    It  must  not  become  I  kelp  ley  has  been  used  in  the  operation, 


moist  in  the  air,  or  throw  out  a  saline  ef- 
florescence on  its  external  surface. 

The  following  methods  of  making  dif- 
ferent kinds  of  soap  are  given  as  speci- 
mens of  those  in  actual  use,  in  a  treatise 
on  soap-making,  by  a  manufacturer,  late- 
ly printed  at  Edinburgh,  to  which  we  have 
been  indebted  for  sundry  observations. 

A  Charge  for  pure  White  Soap. 
The  boiler  being  made  perfectly  clean, 
put  in  10  cwt.  of  best  home  melted  tallow 
(no  resin  is  used  in  white  soap)  with  200 
gallons  of  ley  ;  melt  down  with  a  mode- 
rate fire,  as  the  goods  now  in  hand  are 
something  similar  to  milk,  exceedingly 
apt  to  boil  over. 


the  propriety  of  this  must  be  conspicu- 
ous, for  the  water  pumped  off  will  be  of 
an  exceeding  dark  bottle  green  colour. 
The  finishing  of  white  soap  without  this 
precaution  is  the  sole  cause  of  the  blue- 
ness,  so  frequently  observed  in  this  arti- 
cle when  made  and  brought  to  market. 

The  blue  ley  being  pumped  clean  oft, 
set  again  the  fire,  and  put  into  the  boiler 
six  or  eight  pails  of  water;  and  when 
thoroughly  incorporated  and  boiled  some 
time,  try  if  the  water  run  from  the  soap  - 
:  if  it  do,  add  water  in  small  quantities  at  a 
;  time,  until  it  is  observed  not  to  run,  but, 
j  as  formerly  mentioned  for  yellow  soap,  to 
appear  as  just  starting  from  the  soap ;  in 
j  this  case,  after  giving  a  good  boil,  and 


SOA 


SOA 


swelling  the  soap  up  in  the  pan  to  near  the 
brim,  draw  away  all  the  fire,  and  spread 
it  about  to  die  away.  The  pan  is  now  fi- 
nished, and  may  stand  about  twelve  or 
fourteen  hours ;  and  if  the  quantity  be 
large,  that  is,  two,  three,  or  four  ton,  dou- 
ble this  time  to  stand  will  be  much  in  fa- 
vour of  the  soap,  providing1  always,  that  it 
can  be  kept  very  close  and  warm  in  the 
boiler.  If  any  blueness  still  appear,  re- 
peat the  washing". 

Before  casting,  we  would  recommend 
the  frames  to  have  a  bottom  and  lining-  of 
coarse  cloth,  for  white  soap  only.  After 
all  is  cast  into  the  frames,  let  it  be  well 
stirred,  or  crutched  ;  and  it  is  very  pro- 
per, that  it  also  be  covered  close  up  with 
old  sheets,  bass  mats,  &c.  upon  the  top  of 
the  frame  and  soap,  and  allowed  to  cool 
gradually,  and  all  together. 

In  about  three  or  four  days  (supposing, 
as  formerly,  the  dip  30  inches)  the  cover- 
ings and  frames  may  be  taken  off,  and  the 
whole  cut  up  into  such  size  of  bars  as  may 
best  suit  the  customers. 

To  give  this  white  soap  the  perfume  of 
what  is  commonly  called  Windsor  soap,  a 
little  of  the  essential  oil  of  caraway  seeds 
mixed  with  a  small  portion  of  alcohol  may 
be  incorporated  with  the  soap  when  put- 
ting into  the  frame,  stirring  it  in,  by  little 
at  a  time,  so  as  to  diffuse  it  throughout 
the  whole  mass. 

For  making  Black  or  Green  Soft  Soap. 
The  peculiar  method  pursued  in  mak- 
ing this  soap  differs  considerably  from 
that  of  making  hard  soap.  The  hard  has 
the  whole  of  the  ley  totally  extracted  be- 
fore finishing:  soft  Soap,  on  the  contrary, 
retains  the  whole  of  the  ley  used  in  the 
making ;  becoming,  with  the  other  mate- 
rials employed,  one  compound  body,  call- 
ed soft  soap.  A  few  examples  will  clearly 
explain  the  nature  and  practical  mean's 
made  use  of,  in  producing  this  very  useful 
soap. 

We  shall  now  commence  an  operation 
with  a  charge  for  what  is  called, 

First  Crown  Soft  Soap,  18  Barrels. 

The  quantity  of  ley  requisite  for  the  com- 
pletion of  this  charge  will  be  about  400 
gallons ;  about  one  third  of  which  must 
be  put  into  the  boiler  previous  to  any  of 
the  other  materials  :  afterward  add,  2  c  wt. 
2  qrs.  of  tallow,  2  cwt.  2  qrs.  of  hogs- 
lard,  and  70  gallons  of  olive  oil.  The  ley 
herein  to  be  used  is  supposed  to  be  from 
Hungarian  and  English  (Essex)  ashes. 
The  proportion  is  one  of  the  English  to 
eight  of  the  Hungarian.  The  particular 
mode  of  proceeding  is  thus :  After  the 
ley  is  put  in,  add  the  tallow,  and  light  the 
fire.  When  all  the  tallow  is  melted,  put 
in  the  oil,  and  draw  the  fire  a  little  after- 
VOL.  II. 


ward,  and  allow  the  pan  to  stand  about 
two  hours.  Light  again  the  fire,  and  add 
about  20  gallons  more  of  the  ley.  After 
the  pan  begins  to  boil,  add  now  and  then 
a  little  more  ley,  for  the  purpose  of  pre- 
venting the  soap  from  boiling  over :  and 
this  adding  of  ley  is  to  be  continued,  un- 
til the  soap  is  supposed  to  be  about  half 
boiled  ;  when  it  will  be  time  to  try,  whe- 
ther the  soap  have  got  too  much  or  too 
little  ley- 

This  "trial  is  called  proving,  and  is  neces- 
sary to  be  done  several  times  during  the 
operation,  and  previous  to  the  finishing. 
The  method  of  performing  it  is  this  :  Pro- 
vide a  piece  of  glazed  Dutch  delft,  and  al- 
so a  clear  clean  knife  :  with  the  knife  take 
up  a  piece  of  the  soap  from  the  pan,  and 
if  it  turn  whitish  thereon,  and  fall  from  it 
in  short  pieces  upon  the  delft,  it  is  then  to 
be  concluded,  that  too  much  ley  has  been 
put  in  ;  to  rectify  which,  a  little  more  oil 
must  be  added.  On  the  contrary,  if  the 
soap  want  ley,  it  will  fall  from  the  knife  in 
long-,  ropy  pieces  ;  in  consequence  of 
which  add  some  more  ley.  When,  howe- 
ver, it  happens  to  be  brought  to  perfec- 
tion, neither  wanting  more  lie  nor  oil,  but 
just  in  a  right  state ;  it  will  then  be  ob- 
served, when  taken  upon  the  knife,  to 
stand  the  proper  colour,  not  ropy,  nor  too 
white,  but  transparent.  The  fire  may  now 
be  drawn,  the  soap  being  properly  finish- 
ed, and  ought  immediately  to  be  cast  into 
the  barrels,  firkins,  &c. 

Remember  always,  after  the  second  time 
the  fire  is  lighted,  to  keep  the  soap  boil- 
ing briskly,  till  the  pan  is  nearly  ready, 
when  it  ought  to  boil  slowly,  until  finish- 
ing, and  ready  to  cast. 

A  Charge  for  Second  Crovin  Soft  Soap. 
280  lbs.  of  tallow, 
140  gallons  of  ley, 
82  gallons  of  whale  oil. 

Put  in  100  gallons  of  ley,  with  the  tal- 
low, and  light  the  fire.  When  the  tallow 
is  melted,  add  the  oil,  and  draw  the  fire. 
Let  all  stand  for  two  hours.  Again  light 
the  fire,  and  add  20  gallons  of  ley.  With 
this  the  boiling  is  to  be  continued,  until 
the  soap  is  about  half  finished,  when  10 
gallons  more  of  ley  are  to  be  added.  Dur- 
ing the  remainder  of  the  boiling,  add,  at 
different  periods,  the  other  10  gallons  of 
ley,  which  will  completely  finish  the 
soap. 

A  Charge  for  best  common  Soft  Soap,  with 
Old  Soap  returned. 
254  lbs  tallow, 

85  gallons  train  oil, 
200  gallon's  leys,  weight  11  drachms, 
blue  pearl  ashes. 

At  M.  6,  charged  with  140  gallons  leys, 
and  all  the  tallow,  with  239  lbs.  of  old 
3  c 


SOA 


SOA 


soap.  Set  the  fire.  At  8,  the  oil  put  in, 
and  fire  drawn.  At  10,  the  fire  again 
lighted,  and  40  gallons  of  leys  added 
Prom  this  time  till  E.  2,  at  different  times, 
add  about  15  gallons  leys.  From  this  to 
5,  add  at  different  periods,  five  gallons. 
At  6,  the  fire  may  be  drawn,  and  shortly 
thereafter  the  soap  may  be  cast  into  the 
firkins. 

To  know  when  the  soap  wants,  or  has 
got  too  much  leys,  observe  the  following 
directions.  Take  about  the  size  of  a  pi- 
geon-egg of  the  soap,  while  hot,  and  put 
it  upoi*  the  delft.  Observe  if  whitish 
streaks  and  specks  plainly  appear,  and 
continues  so  after  the  soap  grows  pretty 
cold.  When  this  happens,  the  soap  lias 
got  enough  of  leys.  If  these  appearances 
are  not  evident,  in  that  event,  the  soap 
must  have  more  leys.  Or,  to  know  if  the 
soap  have  got  enough  of  leys,  dip  the 
blade  of  the  knife  into  the  soap ;  and  when 
coldish,  stroak  the  soap  off  the  knife 
upon  your  forefinger  ;  observe  if  any 
streaks  appear  in  the  soap :  if  any,  then 
the  soap  is  plentifully  supplied  with  leys  ; 
but  if  none,  more  leys  must  be  added.  It 
is  always  a  good  sign  that  soft  soap  is 
enough  boiled,  when,  upon  trial  as  above, 
with  the  soap  on  the  finger,  that  it  stands 
up,  and  appears  with  a  thin  roundish  back; 
and  when  right,  it  will  appear  upon  the 
finger  of  a  greyish  colour  at  the  top  of  the 
outer  edge. 

When  different  leys  are  used,  that  is, 
some  strong,  and  others  weak,  particular 
attention  must  be  paid  to  the  proportion- 
ing the  one  with  the  other,  or,  the  weak 
with  the  strong,  in  order  that  a  proper 
strength,  or  boiling  ley,  be  had  from  the 
composition.  If  too  weak  leys  are  used, 
there  is  a  danger  incurred  of  spoiling  the 
whole  soap,  which  is  hardly  to  be  righted 
again. 

To  guard  against  this  great  evil,  ob- 
serve the  following  rule :  Suppose  there 
is  three  leys  of  different  qualities  to  be 
boiled  with,  two  of  them  is  over  weak, 
one  is  too  strong ;  try  their  strength  mix- 
ed together,  thus  : 

drachms.  drachms. 
3  pails,  or  couls,  at  16  each,  is  48 
3  ditto,      ditto,  at  10  ditto,  is  30 
3  ditto,      ditto,  at  8  ditto,  is  24 

9  102 

W^fll3  9  or  1.3  Jthe  standard 

12 
9 


We  now  find,  that  an  equal  proportion 
of  these  leys  mixed  together,  produce., 
upon  an  average,  a  medium  weight,  equal 
to  the  standard  for  proper  boiling  ley. 
Weak  leys  take  always  a  larger  quantity, 
and  much  longei  boiling.  On  the  other 
hand,  strong  leys  take  a  less  quantity  to 
do  the  same  work,  and  considerable  iess 
boiling ;  consequently,  in  using  a  proper 
ley,  both  time  and  fuel  is  saved. 

We  shall  here  give  an  experiment  made 
with  great  precision, to  ascertain  with  re- 
gard to  the  expense  attending  the  making 
of  white  soap  The  only  materials  used, 
of  the  alkali  kind,  was  the  second  sort  of 
potash,  but  of  a  quality  very  superior  to 
what  commonly  is  sold  under  that  deno- 
mination. 

"  I  broke  down  pretty  small,'*  says  a 
manufacturer,  "  a  quarter  cvvt.  of  Ameri- 
can potash ;  and,  with  a  proportionate 
quantity  of  good  lime-shells  mixed  there^ 
with,  set  them  in  a  small  yetlin  cave.  I 
added  water  just  sufficient  to  saturate  the 
mixture.  In  this  state,  having  stood  foe 
about  12  or  14  hours,  I  let  it  run,  and  drew 
off  4  English  gallons  of  ley,  which  I  as- 
certained, by  my  hydrometer,  to  be  14£ 
strong.  1  filled  up  my  cave  with  water, 
ami  continued  the  running  slowly  until  I 
had  28  gallons  more,  of  strength  by  hy- 
drometer 18  strong.  I  then  stopped  up 
my  cave  from  running,  and  proceeded  to 
calculate  the  value  of  my  ley,  as  follows  - 

In  the  first  place,  I  find  that  1-4  cwt.  of 
American  potash,  at  55s.  per  cwt.  (their 
real  price  at  the  time)  is  13s.  9d.  which 
must  be  the  value  also  of  my  3b  gallons 
of  leys,  drawn  from  -the  ashes.  At  that 
rate,  the  English  pint  is  worth  about  two 
farthings,  and  one  half  farthing.  I  now 
proceeded  further  to  complete  my  expe- 
riment, and  satisfy  myself  at  what  expense 
white  soap  could  be  made.  For  this  pur- 
pose, I  charged  a  small  boiler,  which 
holds  about  1^  gallon,  with  4  lbs.  of  good 
rhinded  tallow,  and  with  10  pints  of  the 
ley  of  the  weaker  sort,  or'second  running, 
which  had  been  kept  separate  The  pan 
boiled  very  close,  that  is,  the  leys  and  tal- 
low became  one  mass  of  seemingly  thin 
soap,  without  any  appearance  of  separa- 
tion betwixt  the  leys  and  tallow.  In  this 
state  of  the  pan,  I  was  obliged  to  add  a 
little  salt  and  water,  which  brought  about 
a  separation  in  a  short  time.  I  then  let 
my  pan  stand  off  the  fire  for  half  an  hour, 
when  the  weak  leys  cranned  freely  off.  1 
now  added  six  pints  of  same  leys,  for  se- 
cond boil.  This  had  the  effect  totally  to 
kill  the  tallow,  and  bring  the  soap  to  a 
pretty  strong  consistence,  and  the  leys 
cranned  off  without  salt  in  half  an  hour. 
I  then  prepared  for  third  boil,  by  adding 


SOA 

• 

f  pints  more  of  same  leys,  18  strong,  and 
boiled  half  an  hour.  The  soap  appeared 
now  strong,  but  rather  close;  and  this 
(Closeness  i  attributed  to  too  much  salt; 
to  rectify  which,  I  added  between  one  and 
two  pints  of  water.  This,  in  a  short  time, 
had  the  effect  to  bring  on  a  separation. 
The  pan  was  taken  off"  the  fire,  and  allow- 
ed to  stand  about  an  hour  and  a  half, 
•when  it  parted  freely  with  all  the  leys. 
Nothing  remained  now  to  be  done  but 
finishing,  which  I  completed  with  between 
3  and  4  pints  of  water  (some  salt  also  was 
used,)  in  the  course  of  an  hour  and  a 
quarter  The  pan  was  now  taken  off  the 
fire,  and  allowed  to  cool  lor  24  hours, 
when  I  found,  upon  weighing,  I  had  10$ 
pounds  of  good  white  soap.  Upon  look- 
ing over  my  jottings,  taken  during  the 
operation,  i  found  that  there  had  been 
used  about  23  pints  of  leys,  and  about  3 
pounds  of  salt. 

The  expense  of  the  whole  will  be  evi- 
dent by  the  following  correct  statement, 
viz. 

s.  d. 

To  tallow  4  lbs,  at  7\d.  per  lb.       2  6 
Leys,  23  pints,  at  2$  farthings 

per  pint         -  1  2-\ 

Salt,  3  lbs.  at  |d.  per  lb.  0  1$ 
Duty  charged  on  10$  lb.  soap, 

at  2}d.per  lb.  say       -       1  9 
Fire,  &c  about      -        -     0  2\ 


Total  expense       -       5  9 


TSy  10}2  lbs.  of  soap,  at  9d.  per  lb. 
(white  soap  was  at  that  time 
selling  in  the  shops  at  lOd.)  7  10$ 

Neat  profit     -       2  1$ 

A  boiling  of  hard  soap  sometimes  may 
"Jnisgive,  or  go  wrong.  It  is  then  said  to 
"be  a  spoiled  pan.  In  this  state,  much  trou- 
ble and  expense,  to  an  inexperienced 
boiler,  is  the  consequence,  before  such 
soap  can  be  brought  right.  By  attending, 
however,  to  the  rules  already  laid  do*n, 
such  a  circumstance  will  seldom  happen. 

Instances  of  what  are  called  spoiled  pans 
of  soap,  or  soap,  from  inexperience  in  the 
course  of  making,  converted  into  an  un- 
common mass,  so  as  to  baffle  the  utmost 
skill  of  the  manufacturer  to  redeem,  have 
frequently  happened;  though  with  the 
experienced  and  well  informed  soapmaker 
such  disastrous  failures  will  seldom  or 
never  occur,  the  causes  to  him  being  evi- 
dent. 

No  soap  ley  at  any  time  ought  to  be 
used,  but  such  as  by  experiment  is  proved 
to  be  a  caustic  ley,  entirely  freed  from  its 


SOA 

fixed  air,  and  the  soap  will  always  b* 
good. 

The  olive  oil,  Marseilles,  and  other 
soaps,  are  sometimes  artificially  marbled, 
or  streaked  throughout  their  whole  sub. 
stance  with  red  or  blue  veins.  Tins  soap 
is  harder  than  the  white  soap  of  the  same 
materials,  because  it  requires  to  be  dried 
to  a  greater  degree  to  take  the  marbling. 
This  is  performed  by  adding  to  the  soap, 
as  soon  as  it  is  completely  made  and  se- 
parated from  the  spent  ley,  a  fresh  quan. 
tity  of  ley,  and  immediately  after  a  solu- 
tion of  sulphat  of  iron.  A  decomposition 
between  the  two  takes  place,  and  a  black 
oxyd  of  iron  is  separated  which  is  entan- 
gled within  the  liquid  soap.  The  boiler 
is  then  cooled,  and  the  ley  which  settles 
is  drawn  oil,  after  which  the  soap  is  again 
melte^.  A  workman  then  stands  over  the 
boiler,  and  stirs  the  soap  with  a  wooden 
instrument,  whilst  another  throws  in  at 
intervals  a  quantity  of  colocothar,  or 
brown  red  oxyd  of  iron,  ground  up  with 
water  into  an  uniform  liquid.  This  dif- 
fuses both  the  oxyds  through  the  soap, 
which  is  then  cooled  and  framed.  There 
appears  to  be  some  manual  dexterity  re-* 
quired  in  stirring  these  ingredients  to- 
gether, so  as  to  diffuse  the  marbling  suffi- 
ciently through  the  mass  without  mixing 
it  completely. 

All  the  soaps  which  we  have  hitherto 
mentioned  are  made  with  soda  in  one 
formor  other,  which  alkali  appears  too,  to 
have  been  of  the  most  ancient  use  in  soap- 
making;  but  there  is  another  species  in 
which  the  sole  alkali  is  the  vegetable  in 
the  form  of  pearl-ash,  pot.ashes,  wood- 
ashes,  and  the  like,  and  in  which  no  com- 
mon salt  is  employed.  These  potash 
soaps,  differ  essentially  from  the  others  in 
remaining  always  soft  and  pasty  however 
long  they  are  kept-  On  this  account  they 
are  not  employed  in  common  domestic 
uses,  but  are  chiefly  used  in  scouring 
wool,  and  other  purposes  of  manufacture. 
However,  as  they  are  perfect  soaps,  and 
entirely  soluble  in  water,  they  may  be 
partially  employed  in  rendering  water 
soapy  for  any  purpose  of  cleansing. 

Soft  soap  is  always  coloured,  generally 
of  a  brown  or  deep  green,  which  however 
only  depends  on  the  nature  of  the  oil  used, 
for  with  olive  oil  it  is  white.  It  is  much 
stronger  and  more  acrid  than  the  hard 
soaps,  but  in  other  respects  it  has  the 
same  chemical  properties.  The  consist- 
ence should  be  that  of  a  tenacious  paste 
or  glue,  even  in  the  hottest  summer,  and 
it  should  melt  readily  in  water,  forming  a 
white  and  light  froth.  The  mode  of  ma- 
nufacture of  this  soap,  differs  in  this  es- 


SOA 


SOA 


sential  particular  from  the  other,  that  no 
Separation  takes  place  between  the  soap 
and  the  spent  ley  as  in  the  soda  soaps, 
but  ihe  whole  contents  of  the  boiler,  after 
sufficient  bo  ling  and  evaporation  are  con- 
verted mto  soap ;  neither  is  there  any  of 
the  process  of  framing  and  drying  A 
good  deal  of  practical  skill  also  (more 
than  can  be  learnt  from  books)  seems  to 
be  requiied  in  producing  the  proper  union 
between  the  oil  and  alkali,  and  the  pro- 
cess appears  liable  to  sudden  and  often 
unaccountable  failures  as  before  noticed, 
from  the  refusal  of  the  materials  to  unite 
with  sufficient  intimacy,  or  from  their  dis- 
union after  having  already  combined. 

The  manufacture  of  the  best  soft  soap 
in  Flanders  and  Picardy  is  thus  described. 
The  oils  used  in  these  works  are  linseed, 
hemp,  poppy,  coleseed  and  rape.  Of  these 
the  two  last  are  the  cheapest  and  least  es- 
teemed. Fish  oil  also  answers  perfectly 
well,  but  the  offensive  smell  of  the  soap 
made  from  it  is  so  permanent,  that  its  use 
is  forbidden.  The  alkali  is  generally 
Dantzic,  or  Russian  pearl-ash,  which  is 
mixed  with  lime  and  lixiviated  till  a  lev 
Strang  enough  to  bear  an  egg  is  obtained, 
and  only  one  degree  of  strength  is  used,  ex- 
cept reserving  a  weaker  ley  for  occasional 
dilution  of  the  ingredients.  The  boilers 
are  the  same  as  for  hard  soap,  and  should 
not  be  rilled  more  than  half  full,  on  ac- 
count of  the  great  rising-  of  the  contents 
whilst  they  are  incorporating  The  pro- 
portions of  the  materials  are  on  an  average 
about  30  parts  ot  oil  to  40  of  strong  ley, 
which  yield  about  65  parts  of  soup.  The 
management  of  the  boiling,  and  gradual 
addition  of  the  lew  to  the  oil,  require  con- 
siderable attention,  and  if  it  has  succeed- 
ed properly,  the  oil  and  alkali  unite  into 
an  uniform  gluey  saponaceous  mass,  after 
which  the  boiling  is  continued  till  enough 
of  the  watu-y  part  has  evaporated  to  leave 
the  remainder  of  the  proper  consistence 
when  cold,  which  is  known  to  be  the  case 
when  a  sample  taken  out  and  cooled  does 
not  ^'ickto  the  fingers  and  draw  out  in 
threads,  but  remains  brown,  somewhat 
stiff",  and  granulated.  The  boiler  is  then 
entirely  emptied,  and  the  soap  is  barrell- 
ed for  sale. 

When  the  boiling  has  not  been  conti- 
nued long  enough,  the  soap  is  apt  to  fer- 
ment, and  spoil  by  keeping. 

Soap,  we  have  said,  is  manufactured 
principal  y  from  talTow  or  any  oilier  fat ; 
and  tiie  alkali  employed  is  cither  barilla 
or  pearl  ash,  or  a  mixture  of  the  two,  ac- 
cording to  the  price  and  practice  of  the 
manufacturer  Put  as  potash  alone  will 
not  make  a  stiff  soap,  rt  course  is  had 
to  the  action  of  common  salt,  which, 


when  added  after  the  potash  and  oil  are 
united,  produces  a  separation  of  the  com- 
pound from  the  water  incorporated  with 
it,  hardens  it,  and  renders  it  equal  to  the 
soda  soaps.  The  process  has  been  alrea- 
dy mentioned. 

With  regard  to  the  proportion  of  ingre- 
dients in  making  soap,  it  is  reckoned  that 
16  bushels  of  good  wood-ashes  are  equal 
in  alkali  to  1  cwt.  of  the  best  pearl-ash, 
and  that  this  latter  quantity  will  satuiate 
2  cwt.  of  tallow,  and  produce  3  cwt.  lqr. 
of  soap ;  so  that  12  parts  of  tallow  will 
make  20  of  soap.  Also,  12  bushels  of 
wood-ashes  are  reckoned  equal  to  1  cwt. 
of  barilla,  and  the  latter  quantity  will  sa- 
turate 1  h  cwt.  of  tallow.  A  boil  of  29  cwt. 
of  tallow  with  10  cwt-  of  barilla,  and  5  cwt. 
of  pearl-ash  (as  these  alkalies  are  often 
mixed)  requires  about  8  cwt.  of  common 
salt. 

Common  salt,. it  is  hardly  necessary  to 
repeat,  appears  to  have  two  distinct  uses 
in  soap-making;  one  is,  that  of  promoting 
the  graining,  or  separation  of  the  soap 
from  the  spent  ley,  which  it  doe's  proba- 
j  bly  simply  by  abstracting  the  watery  part. 
I  In  this  way  it  is  of  as  much  use  in  the  so- 
i  da,  as  the  potash  soaps,  and  in  each  it 
1  considerabl}  hastens  the  process  ;  but  it 
is  by  no  means  essential,  and  on  account 
of  its  high  price  appears  to  be  seldom 
tised,  where  barilla  or  soda  is  the  sole  al- 
kali.   But  where  a  large  portion  of  the 
alkali  is  potash,  the  soap  would  remain  in 
the  state  of  a  soft  pasty  mass  (as  we  have 
ah  ead}-  seen)  and  actually  does  so,  till  the 
addition  of  common  salt,  which  then 
brings  the  soap  to  the  same  state  as  the 
soda  soaps. 

It  is,  therefore,  probable,  as  suggested 
by  Pelletier,  that  in  these  cases  a  double 
decomposition  takes  place  between  the 
oil  and  potash  on  the  one  hand,  and  the 
muriatic  acid  and  soda  on  the  other,  and 
that  the  products  of  this  change  of  prin- 
ciples are  a  soap  with  oil  and  soda,  and 
muriat  of  potash  in  the  mother  liquor. 

In  the  preparation  of  all  the  hard  soaps, 
a  separation  of  the  soap  from  the  watery 
saline  solution  always  takes  place  towasds 
the  end  of  the  process,  and  it  is  this  sepa- 
ration which  enables  the  artist  to  collect 
and  dry  the  soap.  But  the  question  oc- 
curs, how  this  separation  takes  place;  for 
the  liquor  from  which  it  separates  is  still 
alkaline,  often  very  strongly  so,  and  if  the 
same  soap,  after  it  is  fully  prepared  and 
dry,  is  re-dissolved  in  an  alkaline  liquor, 
it  will  mix  with  it  uniformly  into  a  white 
saponaceous  fluid. 

Pelletier  has  endeavoured  to  shew  by- 
some  ingenious  reasoning,  and  by  experi- 
ment, that  carbonic  acid,  which  is  con- 


SOA 


SOA 


trary  to  many  opinions,  is  an  essential  in- 
gredient in  the  hard  soaps,  and  from  the 
Fact  that  caustic  alkali  will  decompose  al- 
cohol, and  become  more  or  less  carbona- 
ted by  the  carbonic  acid,  which  is  thereby 
g-enerated,  (tor  which  see  the  article  Po  t- 
ash,) he  infers  that  during  soap-boiling, 
the  pure  alkali,  and  oil,  first  unite  into  a 
saponaceous  mass,  during  which  he  sup- 
poses that  part  of  the  oil  is  decomposed, 
and  furnishes  carbonic  acid,  which  then 
unites  with  the  saponaceous  fluid,  and 
forms  with  it  a  triple  compound  of  oil,  al- 
kali, and  carbonic  acid,  which  constitutes 
hard  soap.  In  the  preparation  of  soap 
without  heat,  he  further  supposes,  that 
part,  if  not  all,  of  the  carbonic  acid,  may 
be  furnished  by  the  atmosphere,  which 
will  account  for  the  length  of  time  re- 
quired before  the  soap  made  in  this  way 
will  harden  and  separate  from  the  ley. 

To  this  hypothesis,  however,  we  may 
object,  that  there  is  no  proof  brought  that 
soap  actually  contains  carbonic  acid,  and 
the  contrary  may  be  inferred  from  its  not 
effervescing  with  a  stronger  acid. 

When  a  solution  of  soap  in  alcohol  is 
poured  into  river  or  spring  water,  a  pre- 
cipitation ensues,  and  a  great  part  of  the 
precipitate  is  no  longer  soluble  in  water. 
All  soaps  are  decomposed  again  by  acids, 
and  the  fat  matter  separated  from  them. 
The  alteration  however,  which  the  fat  and 
oils  undergo  on  this  occasion,  is  very  re- 
markable. They  are  now  soluble  in  al- 
cohol, whereas  before,  the  case  is  quite 
otherwise  ;  the  cause  of  which  depends 
on  the  action  of  the  caloric  upon  these  bo- 
dies ;  and  indeed  the  naked  fire  manifest- 
ly exerts  the  same  effect  upon  them  in 
such  cases,  in  which  it  converts  them  into 
empyreumatic  oils 

With  mere  lime-water  a  saponaceous 
greasy  mixture  only,  but  no  solid  soap 
can  be  obtained.  Besides  the  above-men- 
tioned fat  substances,  a  resinous  soap  may 
also  be  made  from  the  coarser  kinds  of 
resin  with  caustic  ley. 

Chaptal  gives  the  following  classifica- 
tion of  matters,  with  which  soaps  may  be 
made,  arranged  according  to  the  good- 
ness of  the  produce. 

1.  Oil  of  olives  and  of  almonds. 

2.  Suet,  hogs-lard,  butter  and  the  fat 
of  horses. 

3.  Rape  oil. 

4.  Oil  of  beech-mast  and  poppy  seeds. 

5.  Fish  oil. 

6.  Oil  of  hempseed,  nuts,  and  linseed. 
Thecompound  resulting  from  this  union 

partakes  at  the  same  time  of  the  proper- 
ties of  oil  and  of  alkali;  but  these  pro- 
perties are  modified  and  tempered  by  each 
other,  according  to  the  general  rule  of 


combinations.  Alkali  formed  into  soap, 
has  not  nearly  the  same  acrimony  as  when 
it  is  pure ;  it  is  even  deprived  of  almost 
all  its  causticity,  and  its  other  saline  alka- 
line properties  are  almost  entirely  abolish- 
ed. The  same  oil  contained  in  soap,  is 
less  combustible  than  when  pure,  from  it» 
union  with  the  alkali,  which  is  an  unin- 
flammable body.  It  is  miscible,  or  even 
soluble  in  water  to  a  certain  degree,  by- 
means  of  the  alkali.  Soap  is  entirely  so- 
luble in  alcohol. 

Concerning  the  decomposition  of  soap 
by  means  of  acids,  we  must  observe,  first, 
that  all  acids,  even  the  weakest  vegeta- 
ble acids,  may  occasion  this  decomposi- 
tion, because  every  one  of  them  has  a 
greater  affinity  than  oil  with  fixed  alkali. 
Secondly,  these  acids,  even  when  united 
with  any  basis,  excepting  a  fixed  alkali, 
are  capable  of  occasioning  the  same  de- 
composition ;  whence  all  ammoniacal 
salts,  all  salts  with  bases  of  earth,  and  all 
those  with  metallic  bases,  are  capable  of 
decomposing  soap,  in  the  same  manner  as 
disengaged  acids  are ;  with  this  difference, 
that  the  oil  separated  from  the  fixed  al- 
kali, by  the  acids  of  these  salts,  may  unite 
more  or  less  intimately  with  the  substance, 
which  was  the  basis  of  the  neutral  salt 
employed  for  the  decomposition. 

Soap  may  also  be  decomposed  by  distil- 
lation, as  Lemery  has  shown.  When  first 
exposed  to  fire,  it  yields  a  phlegm  called 
by  him  a  spirit;  which  nevertheless  is 
neither  acid  nor  alkaline,  but  some  water, 
which  enters  into  the  composition  of  soap. 
It  becomes  more  and  more  coloured  and 
empyreumatic  as  the  fire  is  increased, 
which  shows,  that  it  contains  the  more 
subtile  part  of  the  oil. 

As  all  oils  contain  an  acid  more  or  less 
combined,  which  may  also  be  more  or  less 
disengaged  by  the  oil  becoming  rancid, 
by  the  action  of  heat,  or  by  combination 
with  other  bodies,  probably  a  portion  of 
the  alkali  of  the  soap  is  saturated  with 
the  acid  of  the  oil,  especially  alter  the  dis- 
tillation of  the  soap.  But  this  matter  has 
not  been  so  well  examined,  that  we  can 
affirm  any  thing  concerning  it. 

As  to  the  chemical  properties  of  soap, 
we  defer  treating  of  them  in  this  place, 
and  refer  the  reader  to  chemical  books. 

SOAP,  Glass -maker's.  Oxyde  of  manga- 
nese. 

SOAP  OF  WOOL.  -In  the  first  volume 
of  the  Memoirs  of  the  National  Institute, 
Mr.  Chaptal  has  given  an  account  of  a  new 
soap,  formed  by  the  combination  of  wool 
and  an  alkali.  As  he  has  entered  into  a  de- 
tail of*  its  uses,  as  well  as  its  composition, 
we  shall  give  t  hem  nearly  in  his  own  words. 

In  every  manufactory  of  woollen  cloths 


SOA 


SOA 


it  is  usual  to  full  the  cloth  immediately 
after  it  has  passed  the  loom.  The  opera- 
tion is  performed  not  only  for  the  purpose 
of  clearing  it  of  the  oil,  but  to  give  it  the 
requisite  density.  For  this  purpose  about 
thirty  pounds  of  soap  are  used  for  every 
eight  pounds  of  cloth. 

Hence  it  is  obvious,  how  greatly  bene- 
ficial it  must  prove  to  the  manufacturer, 
to  be  able  to  substitute  without  difficulty, 
instead  of  the  soft  soap,  another  compound 
of  materials,  easy  to  be  procured,  and  of 
moderate  cost. 

The  whole  operation  consists  in  making 
an  alkaline  lixivium  of  wood  ashes,  or 
potash,  and  dissolving  therein,  at  the  boil- 
ing heat,  old  rags*  or  clippings  of  wool 
to  the  point  of  saturation.  The  product 
is  a  soft  soap,  very  soluble  in  water,  of  a 
green  grayish  colour,  well  blended,  and 
possessing  an  animal  smell,  which  the 
cloths  lose  by  washing  and  exposure  to 
the  air. 

The  various  experiments  I  have  made 
on  this  subject  have  presented  the  follow- 
ing results : 

1.  As  soon  as  the  wool  is  plunged  into 
the  boiling  liquid,  the  filaments  adhere  to- 
gether, and  a  slight  agitation  is  sufficient 
to  effect  the  complete  solution. 

2.  The  ley  becomes  coloured,  and  gra- 
dually thickens,  in  proportion  as  more 
wood  is  added. 

3.  The  soap  is  more  or  less  coloured, 
accordingly  as  the  wool  is  less  or  more 
clean  and  white. 

4.  The  piie,  or  hairs,  which  are  mixed 
with  the  wool,  are  more  difficult  of  solu- 
tion. 

5.  The  quantity  of  wool  the  alkali  is 
Capable  of  dissolving  depends  upon  the 
strength  of  the  lixivium,  its  causticity,  and 
the  degree  of  heat.  Two  pounds  three 
ounces  and  six  drachms  of  caustic  alkali, 
at  twelve  degreesf  of  concentration,  and 
at  the  boiling  heat,  dissolved  ten  ounces 
four  drachms  of  wool.  The  soap,  when 
cooled,  weighed  one  pound  four  ounces. 

An  equal  quantity  of  alkali,  at  the  same 
degree  of  causticity,  l>eat,  and  concentra- 
tion, m  which  he  dissolved  four  ounces  of 
wool,  did  not  acquire  consistence  suffi- 
cient to  answer  several  of  the  purposes 
required 

An  equal  quantity  of  alkali,  marking 
four  degrees,  dissolved  only  two  ounces 


seven  drachms  of  wool.  The  soap,  when 
cooled,  weighed  fourteen  ounces.  It  was 
of  a  good  consistence. 

6.  In  proportion  as  the  wool  is  dissolv- 
ed in  the  lixivium,  the  solvent  power  of 
the  alkali  decreases,  and  at  last  it  takes 
up  no  more.  It  is  at  this  period,  namely, 
when  the  wool  being  agitated  in  the  fluid 
is  no  longer  dissolved,  that  the  operation 
must  be  terminated. 

I.  The  Choice  and  Preparation  of  Mate- 
rials. 

The  materials  required  to  form  this 
soap  are  two,  alkaline  matters  and  wool, 

The  alkaline  substances  may  be  obtain- 
ed from  the  ashes  of  common  c  linary 
fires,  and  the  ley  made  by  the  well-known 
processes.  Lime  is  to  be  slaked  with  a 
small  quantity  of  water ;  the  paste  is  to 
be  mixed  with  sifted  wood-ashes,  in  the 
proportion  of  one  part  of  quicklime  by 
weight  to  ten  of  the  ashes.  The  mixture 
is  to  be  put  into  a  small  stone  trough  (for 
wooden  vessels  colour  the  ley  and  become 
speedily  useless),  and  water" is  to  be  pour- 
ed on  to  the  depth  of  some  inches.  After 
a  certain  time  the  solution  may  be  drawn 
off  at  an  aperture  in  the  bottom  of  the 
vessel  for  this  ptnpose.  It  must  not  be 
drawn  off  till  the  moment  previous  to  its 
use,  and  may  be  in  strength  from  four  to 
fifteen  degrees.  But  indeed  it  is  of  little 
consequence  what  the  strength  may  be, 
because  the  only  difference  resulting  from 
the  use  of  a  weak  or  strong  ley  is,  that 
the  quantities  of  wool  which  are  dissolv- 
ed will  differ  accordingly. 

The  potash  of  commerce  may  be  em- 
ployed in  the  same  manner,  by  mixing  it 
with  one-third  of  its  weight  of  quicklime. 

As  to  the  choice  of  the  wool,  every  one 
knows,  that  in  the  manufactories  of  wopl- 
len  cloths  of  every  kind,  there  are  a  num- 
ber of  operations  performed,  from  the  first 
washing  of  the  material  to  the  last  pack? 
age  of  the  finished  article,  which  occasion 
more  or  less  of  loss.  The  water  in  which 
the  wool  is  agitated  to  cleanse  it,  the  floor 
on  which  it  is  spread  out,  the  warehouse 
where  it  is  depositedj  all  afford  waste 
wool;  as  do  the  operations  of  beating-, 
carding,  spinning,  weaving,  shearing,  nap- 
ping, and  fulling.  In  all  these  several 
manipulations,  we  every  where  see  a  resi- 
due of  wool,  which,  it  is  true,  is  collected 


*  Old  woollen  rags  are  a  very  cheap  article  in  this  country.  But  as  every  other 
kind  of  hair  must  certainly  answer,  and  horns  and  hoofs  probabty  will,  there  must  be 
an  immense  and  probably  "cheaper  source  in  the  refuse  of  the  tanners,  hog-butchers, 
homers,  and  comb-cutters.    All  these  at  present  are  used  only  as  manure. 

\  Qu.  By  what  measure  ?  It  is  greatly  to  be  wished,  that  all  measures  derived 
from  the  density  of  fluids  were  reduced  to  the  common  expression  of  the  tables 
Kterem  water  is  taken  as  unitv,  or  1000. 


SOA 


SOA 


Mb  some  care ;  but  many  of  these  ope- 
rations  are  of  such  a  nature,  that  the  re- 
mains of  wool  they  afford  are  solid  and 
mixed  with  foreign  matters,  or  else  cut 
and  rendered  too  short  to  enter  into  other 
fabrics,  so  that  they  are  mostly  thrown  on 
the  dunghill.  This  manufacture  of  soap 
affords  the  means  of  converting  them  all 
to  use.  Nothing  more  is  required  but  to 
collect  them  all  in  those  baskets  in  which 
the  wool  is  washed,  and  to  wash  them 
with  care  for  the  purpose  of  separating- 
impurities  and  foreign  substances:  after 
which  they  are  to  be  reserved  for  this 
use. 

The  cuttings  of  all  the  woollen  stuffs 
afforded  by  the  shops  of  manufacturers, 
dealers,  tailors,  and  the  like,  may  be  ad- 
vantageously collected  for  this  purpose : 
and  the  same  advantage  may  be  derived 
from  the  remains  of  garments  after  they 
are  worn  out. 

II.  Method  of  Making  ihe  Soap. 

When  the  ley  and  the  wool  are  both 
ready,  it  remains  only  to  cause  the  ley  to 
boil  in  a  vessel  of  the  common  form.  When 
it  has  arrived  at  this  point,  the  wool  is  to 
be  added  by  small  quantities  at  a  time, 
and  agitated  to  cause  a  more  speedy  solu- 
tion. Care  must  be  taken  not  to  add  more 
wool,  until  the  first  portions  are  dissolved. 
The  operation  must  be  stopped  the  mo- 
ment the  liquor  refuses  to  dissolve  more. 

From  the  operations  in  the  large  way, 
made  by  Michael  Fabreguettes,with  soaps 
of  his  own  fabrication,  after  the  method 
I  communicated  to  him,  it  is  certain,  that 
this  soap  cleans,  felts,  and  supples  the 
cloths  perfectly  well.  But  its  use  requires 
a  few  important  observations  to  be  made. 

1.  When  the  soap  is  not  made  with  the 
requisite  care,  or  when  dirty  or  coloured 
wool  has  been  employed,  the  cloth  re- 
ceives from  the  soap  a  gray  tinge,  which 
it  is  very  difficult  to  eradicate.  This  tinge 
is  of  no  consequence  when  the'cloth  is  in- 
tended to  be  dyed;  but  it  would  injure 
the  beauty  of  that  white  colour,  which  in 
certain  goods  is  intended  to  be  preserved. 
The  remedy  consists  in  employing  the 
most  select  materials,  to  form  the  soap  in- 
tended for  such  uses. 

2.  Cloths  fulled  with  this  soap  contract 
an  animal  odour,  which,  though  not  very 
strong,  is  nevertheless  disagreeable ;  but 
water  and  the  air  completefy  remove  it. 

After  having  succeeded  in  the  employ 
of  this  soap  in  fulling  cloths  made  of  wool, 
I  attempted  to  substitute  soda  for  pot- 
ash, and  to  form,  according  to  the  pro- 
cess here  described,  a  solid  soap,  proper 
ibr  the  operation  of  dyeing  cottons.  My 


experiments  have  succeeded  beyond  my 
hopes. 

Forty-six  pounds  of  soda  at  eight  de- 
grees dissolved  at  the  temperature  of 
ebullition  five  pounds  of  wool,  and  afford- 
ed by  cooling  sixteen  pounds  fourteen 
ounces  of  soap  sufficiently  solid  not  to 
spread  (couUr). 

The  first  wool  which  is  thrown  into  the 
soda  dissolves  readily,  but  it  is  afterward 
seen,  that  the  fluid  gradually  becomes 
thicker,  and  that  the  dissolution  becomes 
more  difficult  and  slow. 

The  first  solutions  render  the  liquor* 
green,  after  which  it  becomes  black,  and 
the  soap  when  cooled  preserves  a  black*- 
ish  green  colour. 

This  soap  has  been  employed  in  every 
manner,  and  under  every  form,  in  my  ma-, 
nufactory  for  dyeing  cottons  ;  and  1  am  aw 
present  convinced,  that  it  may  be  substi. 
tuted,  instead  of  the  saponaceous  liquid 
we  make  from  the  lixivium  of  soda  and 
oil,  to  prepare  the  cottons.  I  have  con> 
stantly  observed,  that  by  dissolving  a  suf- 
ficient quantity  of  this  soap  in  cold  water 
to  render  the  fluid  milky,  and  by  workin ti- 
the cotton  in  the  manner  well  known,  it  i*» 
sufficient  to  pass  the  cotton  three  times 
through,  drying  at  each  time,  in  order 
that  it  may  be  as  well  disposed  to  receive 
the  dye,  as  that  which  has  been  passed 
seven  times  through  the  ordinary  solu- 
sion  of  soap.  This  will  not  appear  sur- 
prising, when  it  is  considered,  that  animal 
matters  are  very  proper  to  dispose  thread 
and  cotton  to  receive  the  dye,  and  that 
some  of  the  operations  of  our  dye-works 
consist  simply  in  impregnating  them  with 
these  substances. 

It  is  to  be  observed,  that  cotton,  which 
has  passed  through  a  solution  of  this  soap, 
acquires  a  gray  tinge,  nearly  similar  to 
what  it  gains  by  aluming,  while  the  com- 
mon soap-colours  give  it  the  most  beauti- 
ful white  colour.  But  this  gray  colour  is 
not  at  all  prejudicial  to  the  dyeing  pro- 
cesses, as  we  have  remarked  in  speaking 
of  woollens. 

Besides  alkaline  soaps,  there  are  also 
earthy  and  metallic  soaps,  which  are  not 
used  in  the  arts. 

SOAPS,  Essential-Oil.  Starkey's 
Soap. — The  combination  of  the  essential 
oils  with  the  fixed  alkalies  is  much  more 
difficult  than  that  of  the  expressed  oils 
and  fats,  and  much  less  perfect,  so  that  a 
separation  is  liable  to  take  place,  whate- 
ver pains  be  taken  in  the  mixture.  Tlii^ 
kind  of  soap  was  first  introduced  by  an 
alchemist  of  the  name  of  Star  key,  whence 
it  has  taken  its  name.  Starkey's  process 
was  tedious  and  uncertain.   It  consisted 


SOA 


SOD 


iii  putting  in  a  vessel  some  dry  carbonat 
of  potash  with  oil  of  turpentine,  and  sha- 
king- the  mixture  daily  for  six  months, 
during  which  time  part  of  the  oil  com- 
bines with  the  alkali  into  a  saponaceous 
mass,  and  the  remainder  'floats  above  it 
unaltered.  Beaume  has  taken  a  good  deal 
of  pains  to  find  out  the  best  method  of 
making  this  mixture.  His  method  is  the 
following.  Put  in  a  marble  mortar,  or  on 
a  porphyry  stone,  any  quantity  of  dry  car- 
bonat of  potash,  add  to  it  gradually  twice 
or  thrice  its  weight  of  oil  of  turpentine, 
and  rub  them  together  till  the  mixture 
has  the  consistence  of  a  soft  extract;  then 
put  it  into  a  glass  cucurbit,  and  set  it  (at 
rest)  in  a  damp  place,  during  which  the 
mixture  absorbs  much  moisture  from  the 
air,  and  resolves  itself  into  three  portions, 
the  lowest  of  which  is  a  wratery  solution 
of  the  alkali,  the  middle  is  the  soap  re- 
quired, and  the  upper  portion  is  some  un- 
combined  oil  of  turpentine,  generally  yel- 
low or  amber-coloured.  Pour  the  whole 
on  a  strainer  of  double  cloth,  and  the  soap 
alone  remains  on  the  strainer,  which,  af- 
ter draining-  for  some  days,  must  be  again 
rubbed  in  a  mortar,  and  is  then  complete. 
The  alkaline  liquor  that  runs  through  the 
filter  is  somewhat  impregnated  with  the 
oil.  Other  recipes  have  been  given  for 
this  soap,  the  preparation  of  which  has  en- 
gaged more  attention,  perhaps,  than  it 
merits  as  a  medicine,  and  which  need  not 
be  repeated  in  this  place.  This  soap  has 
an  acrid  alkaline  taste,  and  is  very  apt  to 
deliquiate  on  exposure  to  air. 

It  does  not  appear,  however,  that  the 
solid  caustic  alkalies  have  ever  been  used 
for  this  purpose,  so  that  experiments  are 
still  wanting  to  ascertain  the  precise  ac- 
tion of  the  alkalies  on  the  essential  oils. 

SOAP,  Windsor. 

SOAP  OF  SODA,  or  II a b  d 
Soap.  ^See  Soap 

SOAP  OF  POTASH,  or  | 
Soft  Soap.  J 

SOAP-LEES.  Lixivium  saponarium. — 
This  term  has  been  not  unfrequently  used 
both  by  chemical  writers,  and  also  fami- 
liarly, to  signify  the  ley  or  alkaline  lixi- 
vium used  by  soap-boilers.  In  this  coun- 
try, therefore,  it  means  a  very  strong  so- 
lution of  potash,  nearly,  if  not  entirely, 
caustic  ;  but  in  the  countries  where  soda 
is  chiefly  used  by  the  soap-makers,  it  sig- 
nifies a  ley  of  caustic  soda.  It  is  therefore 
an  incorrect  term,  and  is  nearly  disused, 

The  term  soap-lees  is  also  employed 
technically  by  some  to  signify  the  spent 
ley  which  is  pumped  out  of  the  soap  cis- 
tern after  the  soap  has  separated,  and  be- 
iug  generally  more  or  less  alkaline,  it  is 


J  never  thrown  away,  but  is  sometimes  us 
!  ed  again  in  the  state  in  which  it  is  obtain- 
j  ed,  and  at  other  times  is  evaporated,  and 
j  the  residue  calcined  to  extract  the  alkali, 
j  But  owing  to  the  decomposition  of  com- 
j  mon  salt,  in  the  formation  of  hard  from 
I  soft  soap,  the  spent  ley  always  contains 
I  muriat  of  potash. 

SODA- — This  was  formerly  called  the 
mineral  or  fossil  alkali,  because  supposed 
to  belong  exclusively  to  that  kingdom  : 
by  the  London  college  it  is  termed  natron, 
as  there  are  sufficient  grounds  for  con- 
cluding, that  it  was  the  natron,  ornitrum, 
of  the  ancients,  which  was  long  confound- 
ed with  our  nitre ;  but  the  French  name 
soda  has  generally  prevailed. 

Soda  is  found  native  in  many  hot  coun- 
tries, subsaturated  with  carbonic  acid; 
and  in  the  water  of  the  sea,  in  very  large 
quantity,  saturated  with  the  muriatic  acid. 
But  in  Europe  it  is  generally  obtained 
from  plants,  that  grow  in  the  sea  or  on  its 
shores.  In  Scotland  sea  weeds  of  differ- 
ent kinds  are  selected,  dried,  and  burned 
in  pits  dug  in  the  sand,  or  in  heaps  sur- 
rounded with  loose  stones.  Fresh  quanti- 
ties are  added,  as  the  first  are  consumed, 
the  whole  being  frequently  stirred,  till  it 
becomes  semifluid ;  and  when  cold  it  con- 
cretes into  hard  masses.  This  impure  al- 
kali, which  is  of  a  black  or  blueish  colour, 
is  called  kelp,  and  does  not  contain  more 
than  from  2^  lbs.  to  5  lbs.  of  soda  in  100. 

On  the  southern  coasts  of  France,  and 
more  particularly  of  Spain,  different  plant  s 
chiefly  of  the  salsoia  genus  are  cultivat- 
ed for  the  purpose  of  manufacturing  this 
salt.  These  are  burned  in  much  the  same 
manner,  and  the  saline  produce  they  yield 
is  termed  barilla.  That  of  Alicant  is  in 
the  highest  repute.  If  the  plants  that  thus 
produce  soda  be  removed  to  an  irland  si- 
tuation, the  soda  they  yield  by  burning 
gradually  decreases,  till"  at  length  they  af- 
ford no  other  alkali  than  potash. 

From  this  barilla,  or  from  kelp,  the  salt 
is  extracted  by  lixiviation  with  boiling  wa- 
ter, filtration,  and  crystallization.  A  pound 
of  barilla  will  yield  from  three  to  five 
ounces  of  carbonat  of  soda.  This,  being 
crystallized,  is  less  impure  than  the  car- 
bonat of  potash,  extracted  in  a  similar 
manner. 

To  extract  the  carbonic  acid,  and  ob- 
tain the  soda  pure,  quicklime  is  used. 
This,  first  slaked  by  the  addition  of  a  lit- 
tle water,  is  mixed'  with  an  equal  weight 
of  the  carbonat  of  soda,  and  as  much  wa- 
ter as  will  make  the  whole  a  thin  paste. 
The  mixture  being  poured  into  a  funnel 
with  a  filter  of  linen  cloth,  more  water  is 
to  be  added  as  the  solution  passes  through, 


SOD 


SOD 


till  five  or  six  times  the  weight  of  the  car- 
bonat  have  been  employed  If  the  soda 
be  required  very  pure,  this  solution  must 
be  evaporated  to  the  consistence  of  honey, 
and  about  an  equal  quantity  of  alcohol 
added.  After  these  have  stood  a  little 
time  in  a  close  vessel,  the  lighter  fluid  on 
the  top  is  to  be  poured  off  from  the  dark- 
er beneath  and  the  solid  matter  at  the  bot- 
tom, and  part  of  its  alcohol  abstracted  by 
distillation.  The  remainder  on  standing- 
will  again  separate  into  two  portions ;  and 
that  which  floats  like  an  oil  on  the  sur- 
face, being  a  solution  of  the  pure  soda  in 
alcohol,  is  to  be  poured  off  and  evaporat- 
ed in  a  silver  vessel,  so  as  to  obtain  the  al- 
kali in  crystals,  which  are  prismatic,  but 
not  very  regular,  or  in  thin  plates. 

The  soda  is  white,  extremely  acrid  and 
caustic,  powerfully  attractive  of  water, 
and  capable  of  being  fused  and  volatiliz- 
ed by  heat.  With  oil  it  forms  soap,  and 
with  siliceous  earth  glass. 

From  the  uses  to  which  soda  has  been 
applied  in  the  arts,  various  modes  have 
been  suggested  of  obtaining  it  in  the  large 
way.  Mr.  Accum  says  he  has  been  em- 
ployed in  a  soda  manufactory,  in  which 
the  following  method  answered  exceed- 
ingly well :  Five  hundred  pounds  of  sul- 
phat  of  soda  were  introduced  into  an  iron 
boiler,  containing  a  sufficient  quantity  of 
Thames  water.  Five  hundred  and  sixty 
pounds  of  American  potash  were  likewise 
dissolved  in  as  little  water  as  possible,  in 
an  iron  boiler,  fixed  near  the  former.  The 
potash  was  always  previously  tried,  and, 
if  indifferent,  the  quantity  taken  was  ten 
pounds  more. 

The  solution  was  made  with  about  thir- 
ty pails  of  water  to  the  alkali  here  men- 
tioned. Both  solutions  were  then  made 
to  boil,  and  as  soon  as  the  ebullition  took 
place,  the  solution  of  potash  was  ladled 
into  the  boiler  containing  the  sulphat  of 
soda.  The  mixture  was  agitated  during 
the  transfusion,  and  the  lire  raised  as  ex- 
peditiously as  possible. 

As  soon  as  the  fluid  boiled,  it  was  la- 
dled into  a  wooden  gutter,  which  convey- 
ed it  into  a  cistern  of  wood  lined  with 
sheet  lead  nearly  half  an  inch  thick, 
which  was  fixed  in  a  cool  place.  Sticks  of 
wood  were  then  placed  across  the  cistern, 
from  which,  slips  of  sheet  lead  two  or 
three  inches  wide  were  hung  into  the 
fluid,  at  four  inches  distant  from  each 
other.  When  all  was  cool,  which  in  the 
winter  was  generally  the  case  in  three 
days,  a  plug  in  the  bottom  of  the  cistern 
was  drawn,  in  order  to  let  off  die  fluid, 
and  the  crystallized  salt  was  taken  from 
the  slips  of  lead.  The  bottom  exhibited 
a  rock  of  salt,  which  was  detached  bv 
VOL.  II. 


clnsel  and  mallet.  On  this  account  it  is, 
that  the  lead  which  lines  the  cistern  must 
be  thick,  in  order  to  guard  against  acci- 
dents. For,  if  the  metal  be  perforated, 
the  saline  solution  creeps  between  it  and 
the  wood,  and  in  a  very  short  time  de- 
taches the  lining ;  and  it  is  besides  ex- 
tremely difficult  to  find  out  the  place 
where  the  defect  really  is.  The  tempera- 
ture where  the  soda  is  left  to  crystallize, 
ought  not  to  exceed  55°  Fahrenheit. 

In  this  stage  of  the  process  the  whole 
of  the  salt  is  washed  in  the  same^  cistern 
with  cold  water,  to  clear  it  of  impurities  ; 
after  which  it  is  transferred  again  into  the 
boiler,  dissolved  in  clear  water,  and  eva- 
porated by  heat.  As  soon  as  a  strong  pel- 
licle is  formed,  it  is  suffered  to  cool  so  far, 
that  the  hand  may  be  dipped  in  the  fluid 
without  injury,  and  the  heat  is  kept  at 
that  temperatare  as  long  as  effectual  pel- 
licles continue  to  be  formed  over  the 
whole  surface  of  the  boiler,  and  then  fall 
to  the  bottom. 

When  no  more  pellicles  are  formed,  or 
at  least  only  by  blowing  with  the  mouth 
upon  the  surface,  the  fire  is  withdrawn, 
and  the  fluid  is  ladled  out  into  the  cistern 
to  crystallize.  The  sulphat  of  potash, 
&c.  which  had  been  deposited,  are  then 
taken  out  of  the  boiler,  and  put  aside.  II" 
the  fluid  be  suffered  to  cool  pretty  low, 
before  it  is  allowed  to  run  into  the  cistern, 
very  little  sulphat  of  potash  is  found  in 
the  soda  ;  but  in  general  the  rocky  masses 
of  soda  met  with  in  the  market  contain  a 
considerable  quantity.  By  this  process 
from  136  to  139  pounds  of  soda  may  be 
obtained  from  100  pounds  of  sulphat  of 
soda,  if  the  soda  be  crystallized  in  large 
crystals ;  if  small  crystallized,  it  yields 
less. 

We  might  be  inclined  to  suppose,  that 
the  first  operation  was  unnecessary,  and 
that  the  soda  might  be  separated  at  once 
from  the  sulphat  of  potash  at  the  instant; 
of  the  formation ;  but  practice  will  con- 
vince the  operator  otherwise.  A  consider- 
able loss  is  manifested,  if  the  process  be 
not  conducted  in  this  manner ;  though  the 
discovery  of  the  cause  may  perhaps  be  not 
so  easily  accomplished  as  the  proof  of 
the  fact, 

Other  manufacturers  grind  together  five 
cwt.  of  Glauber's  salt  of  the  bleachers, 
and  one  cwt.  of  charcoal :  they  expose 
this  mixture  in  a  reverberatory  furnace 
resembling  a  bake  oven,  till  the  matter, 
when  stirred  with  a  rake,  becomes  pasty. 
It  is  then  withdrawn  and  transferred  into 
large  casks,  each  provided  with  a  double 
bottom.  Water  is  then  suffered  to  stand 
one  inch  high  over  it  for  twenty-four 
hours  ;  the  cock  is  then  opened,  the  sob: 
3  I) 


SOL 


SOL 


lion  runs  through  the  perforated  bottom, 
over  which  a  stratum  of  straw  had  been 
previously  placed;  and  is  thence  con- 
ducted into  the  boiler  for  evaporation  and 
crystallization. 

It  is  a  curious  fact,  that  iron  plates  are 
absolutely  necessary  to  constitute  the  sur- 
face, on  which  these  articles  are  exposed 
to  heat :  fire-bricks  do  not  answer.  It 
seems  as  if  iron  assisted  the  union  5 
though  neither  iron  filings  mixed  with  the 
articles,  nor  pyrites,  are  found  of  advan- 
tage. 

This  method  of  making  soda  is  extreme- 
ly uncertain.  If  the  heat  be  not  raised 
gradually,  or  if  the  mixture  be  not  fused 
enough,  or  a  little  too  much,  it  does  not 
succeed.  The  worst  event  is,  that  when 
the  mixture  has  been  made  too  hot,  sul- 
phuric acid  is  produced,  and  sulphat  of 
potash  is  formed. 

The  quantity  of  soda  which  may  be  ob- 
tained by  this  process,  is  said  to  be  equal 
to  that  obtained  by  any  other  method. 

We  have  lately  been  informed,  that  in 
Germany  soda  is  made  by  decomposing 
the  sulphat  of  soda  by  means  of  acetite  of 
lime  ;  the  acetic  acid  is  obtained  for  this 
purpose  from  wood,  and  the  charcoal  is 
found  to  pay  the  expenses. 

The  method  recommended  by  several 
chemists,  of  obtaining  soda  by  decompos- 
ing sulphat  of  soda  by  the  oxides  or  ace- 
tite of  lead,  does  not  answer  in  this  coun- 
try- The  mass  is  by  far  too  bulky;  and 
requires  too  much  time,  attendance,  and 
fuel,  to  reduce  it  to  a  narrow  compass. 
SOIL.  See  Agriculture. 
SOLDER,  SOLDERING.  The  art  of 
soldering  is  that  of  joining  together  two 
or  more  pieces  of  metal  by  means  of  a 
metallic  cement ;  hence  it  is  absolutely 
requisite,  that  the  solder  employed  should 
have  the  two  following  qualities,  viz.  that 
of  being  fusible  at  a  lower  heat,  than  the 
metals  which  it  is  intended  to  cement,and 
of  adhering  with  considerable  firmness  to 
their  surfaces.  The  solder  for  gold  is 
composed  of  fine  gold,  with  a  or  ^  its 
weight  of  fine  silver,  mixed  together  ac- 
curately by  fusion,  and  afterwards  beat 
out  into  leaves,  somewhat  thinner  than 
card  paper,  and  rendered  as  soft  as  pos- 
sible by  annealing.  It  is  made  use  of  in 
the  following  manner.  A  piece  of  solder 
of  the  proper  size  and  shape  being  cut  off, 
is  laid  on  the  part  to  be  cemented  and 
sprinkled  over  with  pulverized  borax; 
the  flame  from  a  blow-pipe  is  then  appli- 
ed, and  the  borax  and  solder  both  enter 
into  fusion,  the  latter  incorporating  with, 
and  adhering  firmly  to  the  gold :  when 
the  juncture  is  complete  the  piece  is  al- 
lowed to  cool,  and  the  borax  is  removed 


by  boiling  water,  or  what  is  still  better  a 
little  dilute  sulphuric  or  muriatic  acid. — 
The  solder  will  however  appear  consider- 
ably paler  than  the  other  part,  both  on 
account  of  the  silver  with  which  it  is  al- 
loyed, and  of  the  borax,  which  always 
lowers  the  colour  of  gold :  this  defect 
may  be  remedied  by  melting  on  the  sur- 
face of  the  solder,  a  mixture  of  two  parts 
of  nitre,  and  one  of  burnt  alum,  and  af- 
terwards washing  it  off  with  a  soft  brush 
and  hot  water,  by  which  the  natural  co- 
lour of  the  gold,  will  be  restored  and  even 
heightened. 

For  silver  there  are  two  kinds  of  solder 
employed,  the  hard  and  the  soft.  The 
former  is  composed  of  equal  parts  of  sil- 
ver and  fine  brass ;  and  the  latter  is  pre- 
pared by  fusing  the  hard  solder  with  one- 
sixteenth  of  its  weight  of  pure  zinc.  Th 
mode  of  applying  it,  is  the  same  as  al- 
ready directed  for  gold  solder. 

For  copper,  brass,  and  the  hard  alloys 
of  copper,  the  best  hard  solder  is  compos- 
ed of  brass  and  zinc,  in  the  proportion  of 
from  8  to  16  of  the  former,  to  one  of  the 
latter,  according  to  the  required  hard- 
ness. The  soft  solder  is  composed  of  3 
parts  of  zinc  and  one  of  lead,  and  is  ap- 
plied by  means  of  a  common  soldering 
iron,  heated  red  hot. 

The  solder  for  tin,  pewter,  and  lead, 
(or  the  plumber's  solder,)  is  of  two  kinds: 
the  least  fusible  is  composed  of  equal 
parts  of  tin  and  lead ;  the  more  fusible 
contains  besides,  bismuth  in  various  pro- 
portions. A  very  good  soft  solder  is  pre- 
pared, by  melting  together  sixteen  parts 
of  tin,  eight  of  lead,  and  four  of  bis- 
muth. 

For  delicate  works  in  cut  steel,  the 
best  solder  is  gold,  with  a  high  alloy  of 
copper.  For  larger  works  in  iron  and 
steel,  copper  is  made  use  of,  or  an  alloy 
composed  of  equal  parts  of  tin,  and  iron. 

The  following  solders,  from  Imison, 
may  be  useful. 

To  make  Silver  Solder. 

Melt  fine  silver  two  parts,  brass  one 
pait ;  do  not  keep  them  long  in  fusion., 
iest  the  brass  fly  off  in  fumes. 

Another  for  Coarser  Silver. 
Melt  four  parts  of  fine  silver,  and  three 
of  brass  ;  throw  in  a  little  borax,  and  pour 
it  out  as  soon  as  it  is  melted. 

Jl  Solder  for  Gold. 

Melt  copper  one  part,  fine  silver  one 
part,  and  gold  two  parts ;  add  a  little 
borax  when  it  is  just  melted,  then  pour 
it  out  immediately. 


sow 


SOY 


The  Method  of  Soldering  Gold  or  Silver 
After  the  solder  is  cast  into  an  ingot,  it 
would  be  more  ready  for  use,  if  you  were 
to  draw  it  into  small  wire,  or  flat  it  be- 
tween two  rollers  ;  after  that  cut  it  into 
little  bits,  then  join  your  work  together, 
with  fine  soft  iron  wire,  and  with  a  camel's 
hair  pencil,  dipt  in  borax  finely  powder- 
ed, and  well  moistened  with  water,  touch 
the  joint  intended  to  be  soldered  i  placing 
a  little  solder  upon  the  joint,  apply  it  up- 
on a  large  piece  of  charcoal,  and  with  a 
blow-pipe  and  lamp,  blow  it  upon  the 
flame,  until  it  melts  the  solder,  and  it  is 
done. 

To  cleanse  Silver  or  Gold,  after  it  is  Sol- 
dered. 

Make  it  just  red-hot,  and  let  it  cool, 
then  boil  it  in  alum-water,  in  an  earthen 
vessel,  and  it  will  be  as  clean  as  when 
new.  If  gold,  boil  it  in  urine  and  sal  am- 
moniac. 

A  Solder  for  Lead. 
Two  parts  lead  and  one  part  tin  :  its 
goodness  is  tried  by  melting  it,  and  pour- 
ing the  bigness  of  a  crown  piece  upon  the 
table ;  if  it  be  good,  there  will  arise  little 
bright  stars  in  it.  Apply  resin  when  you 
use  this  solder. 

JL  Solder  for  Tin. 
Take  four  parts  pewter,  one  of  tin,  and 
one  of  bismuth ;  melt  them  together,  and 
run  them  into  narrow  thin  lengths. 

SOUP,  PORTABLE    See  Gelatin. 

SOUR  WATER.  Water  is  rendered 
acidulous  by  fermenting  with  bran,  a  pre- 
paration much  used  in  dyeing.  Twenty- 
four  bushels  of  bran  are  put  into  a  tub  or 
vat,  that  will  contain  about  ten  hogsheads: 
a  large  boiler  is  filled  with  water,  which, 
when  just  ready  to  boil,  is  poured  into  the 
vat :  the  acid  fermentation  soon  commen- 
ces, and  in  24  hours  the  liquor  is  fit  for 
use. 

SOWANS.  This  very  nutritious  arti- 
cle of  food  is  made  in  Scotland,  from  the 
husk  of  oats,  by  a  process  not  unlike  that 
by  which  common  starch  is  made.  The 
husk  of  the  oat,  called  seeds,  is  separat- 
ed, from  the  oat  meal  by  the  sieve  ;  but  it 
still  contains  a  considerable  portion  of 
farinaceous  matter.  It  is  mixed  with  wa- 
ter, and  allowed  to  remain  for  some  days, 
till  the  water  has  become  sour.  The 
whole  is  then  thrown  upon  a  sieve  ;  and 
the  milky  water  passes  through,  but  all 
the  husk  remain  behind. 

The  water  thus  obtained,  is  loaded  with 
starchy  matter,  which  soon  subsides  to 
the  bottom.  The  sour  liquor  is  decanted 


off,  and  about  an  equal  quantity  of  fresh 
water  is  added.  This  mixture  when  boil- 
ed, forms  a  very  nutritious  article  of  food ; 
and  the  portion  of  the  sour  water,  which 
still  adheres  to  the  starch,  gives  the  whole 
a  pleasant  acidity- 

It  is  observable,  that  the  starch  maker's 
sour  water,  notwithstanding  the  great 
quantity  of  acid  it  contains,  and  the  still 
sourer  water  of  sowans,  are  swallowed 
greedily  by  hogs,  and  they  fatten  upon 
it. 

SOY.  We  find  in  the  Memoirs  of  the 
Swedish  Academy  the  following  account 
of  the  mode,  in  which  this  kind  of  sauce 
is  prepared. 

The  ingredients  are  fifty  pounds  of  a 
small  white  bean,  the  fruit  of  the  dolichos 
saja,  fifty  pounds  of  salt,  sixty  pounds  of 
wheat  flour,  and  two  hundred  and  fifty 
pounds  of  water. 

After  having  well  washed  the  beans, 
they  are  boiled  in  well-water  in  an  open 
vessel  for  some  hours,  or  until  they  have 
become  so  soft,  as  to  be  worked  between 
the  fing'ers.  During  the  boiling  they  must 
be  kept  covered  with  water,  to  prevent 
their  burning ;  and  care  must  be  Uken, 
not  to  boil  them  too  much,  because  in 
that  case,  too  much  of  their  substance 
would  remain  in  the  water  of  decoc- 
tion. 

The  beans  being  thus  boiled,  are  taken 
out,  and  put  into  large  shallow  wooden 
vessels,  which  in  C  una  are  made  of  thin 
staves  of  bamboo,  two  inches  and  an  half 
in  depth,  and  five  feet  in  diameter.  In 
these  they  are  spread  out  to  the  depth  of 
two  inches,and  when  they  are  cold  enough 
to  be  worked  with  the  hand,  the  wheat 
flour  is  gradually  thrown  in,  and  mixed 
with  the  beans,  till  the  whole  of  the  be- 
fore-mentioned quantity  has  been  used. 
When  the  mass  becomes  too  dry,  so  that 
the  flour  does  not  mix  well  with  the  beans, 
a  little  of  the  hot  water  of  the  decoction 
is  added- 

The  whole  being  well  mixed,  the  mass 
is  spread  abroad  in  the  vessels  before- 
mentioned,  taking  care  that  its  depth  shall 
not  be  more  than  an  inch,  or  an  inch  and  a 
half;  and  it  is  then  covered  by  a  lid,  which 
fits  exactly.  When  the  mass  begins  to 
grow  mouldy,  and  heat  is  disengaged, 
which  happens  after  two  or  three  days, 
the  cover  is  raised,  by  putting  two  sticks 
beneath  it,  in  order  that  the  air  may  have 
free  access. 

During  this  time  a  rancid  odour  ex- 
hales :  and  if  the  mass  become  green,  it 
is  a  sign  that  the  whole  goes  on  properly ; 
but  if  it  begins  to  be  black,  which  must 
be  carefully  noticed,  the  lid  must  be  rais- 


\ 


SOY 


SPE 


ed  higher,  in  order  that  the  mass  may 
have  still  more  air.    If*  it  once  becomes  j 
black,  the  whole  is  spoiled. 

As  soon  as  all  the  surface  is  covered 
with  green  mouldiness,  which  usually 
happens  in  eight  or  ten  days,  the  cover  is 
taken  off,  and  the  compound  is  exposed 
to  the  sun  and  air  for  several  days-  When 
it  has  become  as  hard  as  a  stone,  it  is  cut 
into  small  fragments,  which  are  thrown 
into  an  earthen  vessel,  upon  which  the  two 
hundred  and  fifty  pounds  of  water,  hav-  j 
ing  the  fifty  pounds  of  salt,  first  dissolved  | 
in  them,  are  poured     The  whole  is  then  j 
well  stirred  together,  and  notice  is  taken  J 
of  the  height  at  which  the  water  stands. 
If  it  be  not  convenient  to  put  all  the  mix- 
ture into  one  vessel,  a  number  may  be 
used,  taking  care  that  the  materials  be 
proportionally  distributed  in  each. 

The  vessel  thus  filled  is  placed  in  the 
sun,  and  its  contents  stirred  up  regularly 
every  morning  and  evening  ;  and  a  cover 
is  put  on  at  night  to  defend  it  from  the 
cold,  as  well  as  to  prevent  any  rain  from 
finding  entrance,  either  by  day  or  night. 
The  hotter  the  sun,  the  sooner  will  the 
soy  be  completed.  The  process  is  sel- 
dom undertaken  but  in  summer,  notwith- 
standing which  it  lasts  two  or  three 
months. 

As  the  mass  diminishes  by  evaporation, 
well-water  is  added ;  and  this  digestion 
is  continued,  till  the  salt  water  has  entire- 
ly dissolved  the  flour  and  the  beans.  The 
vessel  is  still  left  for  some  days  in  the  sun, 
in  order  to  complete  the  solution  still  more 
effectually,  as  the  good  quality  of  the  soy 
depends  upon  this  circumstance ;  and  the 
daily  stirring  or  agitation  is  continued  to 
the  very  last. 

When  at  length  the  mass  has  become 
very  succulent  and  oily,  the  whole  as  well 
the  thick  as  the  more  fluid  portions,  is 
poured  into  bags,  through  which  the  soy 
is  pressed,  and  is  then  clear  and  ready  for 
use.  It  is  not  afterwards  boiled,  as  Mr. 
Eckeberg  pretends.  It  is  to  be  kept  in 
bottles  well  corked.  The  Chinese,  who 
deal  in  this  article,  keep  it  in  large  pit- 
chers well  closed.  Before  it  is  strained 
in  the  press,  the  soy  is  of  a  deep  brown 
colour,  but  afterwards  it  becomes  black. 

The  Chinese  also  prepare  two  kinds  of 
soy  from  the  dregs  which  remain.-  The 
first  time  they  add  one  hundred  and  fifty 
pounds  of  water,  and  thirty  pounds  of  salt, 
and  after  having  pressed  the  mass,  they 
again  add  one  hundred  pounds  of  water, 
and  twenty  pounds  of  salt,  always  pro- 
ceeding as  before  described. 

The  two  last  kinds  of  soy  are  not  strong, 
but  very  salt,  more  especially  the  latter, 
which  is  also  lighter  coloured.  These 


two  kinds  are  the  most  common  in  China, 
and  are  used  both  by  natives  and  Euro- 
peans. The  differences  of  price  are  as  8, 
4,  and  1. 

SPANISH  BROWN.  See  Colour 
Making. 

SPANISH  SHEEP.  See  Sheep  and 
Animals,  Domestic. 

SPANISH  WHITE.  The  substance 
originally  called  by  this  name,  is  the  white 
oxyd  or  magistery  of  bismuth,  the  name 
is  often  however  applied  to  washed  chalk 
or  whiting. 

SPAR.  The  term  spar,  in  its  more 
comprehensive  sense,  appears  to  include 
almost  all  the  earthy  crystallized  mine- 
rals, that  are  met  with  in  metallic  veins  ; 
but  by  mineralogists  it  is  applied  to  those 
minerals,  whether  earthy  or  metallic ; 
which  are  crystallized  and  have  a  visible 
foliated  texture.  Thus  we  say  calcareous 
spar,  fluor  spar,  heavy  spar,  felspar,  lead 
spar,  spathose  iron,  &c.  but  not  quartz 
spar.  It  is  not  however,  every  foliated 
crystal  which  is  called  a  spar,  for  neither 
mica  nor  hornblende  bear  this  appella- 
tion. The  adjective  spathose  or  sparry, 
means  composed  of  crystalline  plates,  in 
opposition  to  foliated  or  slaty,  which  only 
imply  composed  of  plates,  without  any  re- 
ference to  crystallization. 

SPECIFIC  GRAVITY.  Boyle  is  among 
the  first  of  our  philosophers,  who  suggest- 
ed the  advantage,  that  chemistry  and 
mineralogy,  might  derive  from  an  atten- 
tion to  the  specific  gravity  of  bodies. — 
Much  advantage  may  be  derived  from  this 
property  in  the  general  determination  of 
the  classes  of  minerals,  and  the  purity  of 
some  metallic  bodies  ;  and  it  is  very  pro- 
bable, that  attention  to  the  specific  gra- 
vities, capacities  for  heat,  fusibilities,1  vo- 
latilities, laws  of  crystallization,  elasticity, 
hardness,  tenacity,  malleability,  and  some 
other  obvious  specific  properties  of  bodies, 
may  produce  a  more  intimate  acquain- 
tance with  the  mutual  actions  of  their 
particles,  than  any  we  have  hitherto  ac- 
quired. 

The  specific  gravity  of  solids,  is  deter- 
mined by  weighing  them  first  in  air,  and 
then  in  water.  The  loss  of  weight,  aris- 
ing from  the  action  of  the  water,  is  equal 
to  that  of  a  mass  of  the  fluid,  possessing 
the  same  dimensions  as  the  solid  itself. 
Whence  it  is  easy  to  construct  a  general 
table  of  specific  gravities,  by  reducing  the 
proportion  of  the  absolute  weight,  to  the 
loss  sustained  by  immersion,  into  terms 
of  which  that  expressing  water  shall  be 
unity.  If  the  solid  be  so  light  as  to  float 
upon  water,  it  is  convenient  to  attach  to 
it  a  heavier  body,  sufficient  to  cause  it  to 
sink,  but  the  weight  of  which  in  water, 


SPE 


SPE 


must  be  added  in  computing  the  loss. 
The  specific  gravity  of  fluids  is  ascertain- 
ed,  by  weighing  a  known  body  immersed 
in  them.  For  the  loss  by  immersion  will 
accurately  show  the  weight  of  the  same 
bulk  of  the  fluid  ;  and,  consequently,  the 
proportion  of  these  several  quantities  to 
1  lie  loss  the  same  solid  sustained  in  water, 
being  reduced  as  in  the  other  case  to  the 
common  standard  of  unity,  will  exhibit 
the  specific  gravity. 

Other  methods  are  likewise  used  in  ex- 
periments with  fluids.  Thus  equal  bulks 
of  different  fluids,  may  be  weighed  by  fill- 
ing a  small  bottle  with  a  ground  stopper, 
with  each  respectively,  and  from  their 
.several  weights,  the  weight  of  the  bottle 
and  stopper  must  be  deducted.  Or  other- 
wise, the  instrument  called  the  hydrome- 
ter, may  be  used.  See  Hydrometer. 
This  possesses  the  advantage  of  portabi- 
lity, speed,  and  a  degree  of  accuracy  not 
easily  obtained,  by  the  use  of  ordinary  ba- 
lances. 

SPECTACLES.  Spectacles  restore  and 
preserve  to  us  one  of  the  most  noble  and 
valuable  of  our  senses;  they  enable  the 
mechanic  to  continue  his  labour,  and  earn 
a  subsistence  by  the  work  of  his  hands, 
till  the  extreme  of  old  age.  By  their  aid, 
the  scholar  pursues  his  studies,  and  re- 
creates his  mind  with  intellectual  plea- 
sures, and  thus  passes  away  days  and 
years  with  delight  and  satisfaction,  that 
might  otherwise  have  been  devoured  by 
melancholy,  or  wasted  by  idleness. 

Some  eyes  require  the  assistance  of 
convex  glasses  to  make  them  see  objects 
distinctly,  and  others  of  concave.  If  either 
the  cornea  or  crystalline  humour,  or 
both  of  them,  be  too  flat,  their  focus  will 
not  be  on  the  retina,  where  it  ought  to  be, 
in  order  to  render  vision  distinct ;  but  be- 
yond the  eye.  Consequently  those  rays 
which  flow  from  the  object,  and  pass 
through  the  humours  of  the  eye,  are  not 
converged  enough  to  unite,  and  therefore 
the  observer  can  have  but  a  very  indis- 
tinct view  of  the  object.  This  is  reme- 
died by  placing  a  convex  glass  before  the 
eye,  which  makes  the  rays  converge  soon- 
er, and  imprints  the  image  duly  on  the 
retina. 

If  either  the  cornea,  or  crystalline  hu- 
mour, or  both  of  them,  be  too  convex,  the 
rays  that  enter  in  from  the  object,  will  be 
converged  to  a  focus  in  the  vitreous  hu- 
mour ;  and  by  diverging  from  thence  to 
the  retina,  will  form  a  very  confused 
image  thereon ;  and  so,  of  course,  the  ob- 
server will  have  as  confused  a  view  of  the 
object,  as  if  his  eye  had  been  too  flat. 
This  inconvenience  is  remedied  by  placing 


a  concave  glass  before  the  eye ;  which 
glass,  by  causing  the  rays  to  diverge  be- 
tween it  and  the  eye,  lengthens  the  focal 
distance  so,  that  if  the  glass  be  properly 
chosen,  the  rays  will  unite  at  the  retina, 
and  form  a  distinct  picture  of  the  object 
upon  it. 

Such  eyes  as  have  their  humours  of  a 
due  convexity,  cannot  see  any  object  dis- 
tinctly at  a  less  distance  than  six  inches ; 
and  there  are  numberless  objects  too 
small  to  be  seen  at  that  distance,  because 
they  cannot  appear  under  any  sensible 
angle. 

General  Rules  for  the  Choice  of  Spectacles . 

The  most  general,  and,  perhaps,  the 
best  rule  that  can  be  given,  to  those  who 
are  in  want  of  assistance  from  glasses,  in 
order  so  to  choose  their  spectacles  that 
they  may  suit  the  state  of  their  eyes,  is  to 
prefer  those  which  show  objects  nearest 
their  natural  state,  neither  enlarged  nor 
diminished,  the  glasses  being  near  the 
eye ;  and  that  give  a  blackness  and  dis- 
tinctness to  the  letters  of  a  book,  neither 
straining  the  eye,  nor  causing  any  unna- 
tural exertion  of  the  pupil. 

For  no  spectacles  can  be  said  to  be  pro- 
perly  accommodated  to  the  eves,  which 
do  not  procure  them  ease  and  rest:  ii 
they  fatigue  the  eyes,  we  may  safely  con- 
clude, either  that  we  have  no  occasion  for 
them,  or  that  they  are  ill  made,  or  not  pro 
portioned  to  our  sight. 

Though,  in  the  choice  of  spectacles, 
every  one  must  finally  determine  for  him- 
self which  are  the  glasses  through  which 
he  obtains  the  most  distinct  vision ;  yet 
some  confidence  should  be  placed  in  the 
judgment  of  the  artist  of  whom  they  arc 
purchased,  and  some  attention  paid  to  his 
directions. 

Of  Preservers,  and  Rules  for  the  Preserva- 
tion of  Sight. 

Though  it  may  be  impossible  to  prevent 
the  absolute  decay  of  sight,  whether  ari- 
sing from  age,  partial  disease,  or  illness  ; 
yet  by  prudence  and  good  management, 
its  natural  failure  may  certainly  be  retard- 
ed, and  the  general  habit  of  the  eyes 
strengthened,  which  good  purposes  will 
be  promoted  by  a  proper  attention  to  the 
following  maxims. 

1.  Never  to  sit  for  any  length  of  time 
in  absolute  gloom,  or  exposed  to  a  blaze 
of  light.  The  reasons  on  which  this  rule 
is  founded,  prove  the  impropriety  of  going 
hastily  from  one  extreme  to  the  othei'j 
whether  of  darkness  or  of  light,  and  show 
us  that  a  southern  aspect  is  improper  for 
those  whose  sight  is  weak  and  tender. 


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2.  To  avoid  reading  small  print. 

3.  Not  to  read  in  the  dusk ;  nor,  if  the 
eyes  be  disordered,  by  candle-light. — 
Happy  those  who  learn  their  lesson  be- 
times, and  begin  to  preserve  their  sight, 
before  they  are  reminded  by  pain  of  the 
necessity  of  sparing  their  eyes  ;  the  frivo- 
lous attention  to  a  quarter  of  an  hour  of 
the  evening,  has  cost  numbers  the  perfect 
and  comfortable  use  of  their  eyes  for 
many  years :  the  mischief  is  effected 
imperceptibly,  the  consequences  are  in- 
evitable. 

4.  The  eye  should  not  be  permitted  to 
dwell  on  glaring  objects,  more  particu- 
larly on  first  waking  in  a  morning ;  the 
sun  should  not,  of  course,  be  suffered 
to  shine  in  the  room  at  that  time,  and  a 
moderate  quantity  of  light  only  should  be 
admitted.  It  is  easy  to  see,  that  for  the 
same  reasons  the  furniture  of  a  bed  should 
be  neither  altogether  of  a  white  or  red  co- 
lour ;  indeed,  those  whose  eyes  are  weak, 
would  find  considerable  advantage  in  hav- 
ing green  for  the  furniture  of  their  bed- 
chamber. Nature  confirms  the  propriety 
of  the  advice  given  in  this  rule ;  for  the 
light  of  the  days  come  on  by  slow  de- 
grees, and  green  is  the  universal  colour 
she  presents  to  our  eyes. 

5.  The  long-sighted  should  accustom 
themselves  to  read  with  rather  less  light, 
and  somewhat  nearer  to  the  eye,  than 
what  they  naturally  like  ;  while  those  that 
are  short-sighted  should  rather  use  them- 
selves to  read  with  the  book  as  far  off  as 
possible.  By  these  means,  both  would 
improve  and  strengthen  their  sight ;  while 
a  contrary  course  will  increase  its  natu- 
ral imperfections. 

There  is  nothing  which  preserves  the 
sight  longer  than  always  using,  both  in 
reading  and  writing,  that  moderate  de- 
gree of  light  which  is  best  suited  to  the 
eyes ;  too  little  strains  them,  too  great  a 
quantity  dazzles  and  confounds  them. 
The  eyes  are  less  hurt  by  the  want  of 
light  than  by  the  excess  of  it ;  too  little 
light  never  does  any  harm,  unless  they 
are  strained  by  efforts  to  see  objects,  to 
which  the  degree  of  light  is  inadequate ; 
but  too  great  a  quantity  has,  by  its  own 
power,  destroyed  the  sight.  Thus  many 
have  brought  on  themselves  a  cataract,  by 
frequently  looking  at  the  sun,  or  a  fire ; 
others  have  lost  their  sight,  by  being 
brought  too  suddenly  from  an  extreme 
darkness  into  the  blaze  of  day.  How 
dangerous  the  looking  upon  bright  lumi- 
nous objects  is  to  the  sight,  is  evident 
from  its  effects  in  those  countries  which 
are  covered  the  greater  part  of  the  year 
with  snow,  where  blindness  is  exceeding- 
ly frequent,  and  where  the  traveller  is 


obliged  to  cover  his  eyes  with  crape,  to 
prevent  the  sudden,  and  often  dangerous 
effects  of  too  much  light:  even  the  untu- 
tored savage  tries  to  avoid  the  danger,  by 
framing  a  little  wooden  case  for  his  eyes, 
with  only  two  narrow  slits.  A  momenta- 
ry gaze  at  the  sun  will,  for  a  time,  unfit 
the  eyes  for  vision,  and  render  them  in- 
sensible to  the  impressions  of  a  milder 
nature. 

The  following  cases  from  a  small  tract 
on  the  Fabric  of  the  Eye,  are  so  applica- 
ble to  the  present  article,  as  to  want  no 
apology  for  their  insertion  here;  though, 
if  any  were  necessary,  the  use  they  will 
probably  be  of  to  those  whose  complaints 
arise  from  the  same,  or  similar  causes, 
would,  we  presume,  be  more  than  suffi- 
cient. 

"  A  lady  from  the  country,  coming  to 
reside  in  St.  James's  square,  London,  was 
afflicted  with  a  pain  in  the  eye,  and  a  de- 
cay of  sight.  She  could  not  look  upon 
the  stones,  when  the  sun  shone  upon 
them,  without  great  pain.  This,  which 
she  thought  was  one  of  the  symptoms  of 
her  disorder,  was  the  real  cause  of  it. 
Her  eyes,  which  had  been  accustomed  to 
the  verdure  of  the  country,  and  the  green 
of  the  pasture-grounds  before  her  house, 
could  not  bear  the  violent  and  unnatural 
glare  of  light  reflected  from  the  stones  ; 
she  was  advised  to  place  a  number  of 
small  orange  trees  in  the  windows,  so 
that  their  tops  might  hide  the  pavement, 
and  be  in  a  line  with  the  glass.  She  re- 
covered by  this  simple  change  in  the 
light,  without  the  assistance  of  any  medi- 
cine, though  her  eyes  were  before  on  the 
verge  of  little  less  than  blindness." 

"  A  gentleman  of  the  law  had  his  lodg- 
ings in  Pall-mall,  London,  on  the  north 
side ;  his  front  windows  were  exposed  to 
the  full  noon  sun,  while  the  back  room, 
having  no  opening  but  into  a  small  close 
yard  surrounded  with  high  walls,  was 
very  dark ;  he  wrote  in  the  back  room, 
and  used  to  come  from  that  into  the  front 
to  breakfast,  &c.  His  sight  grew  weak, 
and  he  had  a  constant  pain  in  the  balls  of 
his  eyes;  he  tried  visual  glasses,  and 
spoke  with  occulists  equally  in  vain.  Be- 
ing soon  convinced,  that  the  coming  sud- 
denly out  of  his  dusky  study  into  the  full 
blaze  of  sun-shine,  and  that  very  often  in 
the  day,  had  been  the  real  cause  of  the 
disorder,  he  took  new  lodgings ;  by  which, 
and  forbearing  to  write  by  candle-light,  he 
was  very  soon  cured." 

Blindness,  or  at  least  miserable  weak- 
ness of  sight,  is  often  brought  on  by  these 
unsuspected  causes.  Those  who  have 
weak  eyes  should,  therefore,  be  particu- 
larly attentive  to  such  circumstances, 


SPE 


SPE 


since  the  prevention  is  easy,  but  the  cure 
may  be  difficult,  and  sometimes  impracti- 
cable. 

'  Whatsoever  care,  however,  be  taken, 
and  though  every  precaution  be  attended 
to  with  scrupulous  exactness  ;  yet,  as  we 
advance  in  years,  the  powers  of  our  frame 
gradually  decay :  an  effect  which  is  gene- 
rally first  perceived  in  the  organs  of  vi- 
sion. 

Age  is,  however,  by  no  means  an  abso- 
lute criterion,  by  which  we  can  decide 
upon  the  sight,  nor  will  it  prove  the  ne- 
cessity of  wearing  spectacles.  For,  on 
the  one  hand,  there  are  many  whose  sight 
is  preserved  in  all  its  vigour,  to  an  ad- 
vanced old  age ;  while,  on  the  other,  it 
may  be  impaired  in  youth  by  a  variety  of 
causes,  or  be  vitiated  by  internal  mala- 
dies Nor  is  the  defect  either  the  same 
in  different  persons  of  the  same  age,  or 
in  the  same  person  at  different  ages ;  in 
some  the  failure  is  natural,  in  others  it  is 
acquired. 

From  whatever  causes  this  decay  arises, 
an  attentive  consideration  of  the  following 
rules  will  enable  every  one  to  judge  for 
himself,  when  his  sight  may  be  assisted 
or  preserved  by  the  use  of  spectacles. 

1.  When  we  are  obliged  to  remove 
small  objects  to  a  considerable  distance 
from  the  eye,  in  order  to  see  them  dis- 
tinctly. 

2  If  we  find  it  necessary  to  get  more 
light  than  formerly ;  as,  for  instance,  to 
place  the  candle  between  the  eye  and  the 
object. 

3.  If  on  looking  at,  and  attentively  con- 
sidering a  near  object,  it  becomes  con- 
fused, and  appears  to  have  a  kind  of  mist 
before  it. 

4.  When  the  letters  of  a  book  run  one 
into  the  other,  and  hence  appear  double 
or  treble. 

5.  If  the  eyes  be  so  fatigued  by  a  little 
exercise  that  we  are  obliged  to  shut  them 
from  time  to  time,  and  relieve  them  by 
looking  at  different  objects. 

When  all  these  circumstances  concur, 
or  any  of  them  separately  take  place,  it 
will  be  necessary  to  seek  assistance  from 
glasses,  which  will  now  ease  the  eyes,  and 
in  some  degree  check  their  tendency  to 
grow  flatter ;  whereas,  if  they  be  not  as- 
sisted in  time,  the  flatness  will  be  consi- 
derably increased,  and  the  eves  be  weak- 
ened by  the  efforts  they  are  compelled  to 
make. 

SPECULUM.  When  tin  is  melted  with 
copper,  it  composes  the  compound  called 
bronze.  In  this  metal  the  specific  gravi-  ! 
ty  is  always  greater  than  would  be  de- 
duced by  computation,  from  the  quanti- 
ties and  specific  gravities,  of  its  compo-  j 


nent  parts.  The  uses  of  this  hard,  sono- 
rous and  durable  composition,  in  the  fa- 
brication of  cannon,  bells,  statues,  and 
other  articles,  are  well  known. 

Bronzes  and  bell-metals  are  not  usual- 
ly made  of  copper  and  tin  only,  but  have 
other  admixtures,  consisting  oflead,zinc, 
or  arsenic,  according  to  the  motives  of 
profit,  or  other  inducements  of  the  ar- 
tist. 13 ut  the  attention  of  the  philosopher, 
is  more  particularly  directed  to  the  mix- 
ture of  copper  and  tin,  on  account  of  its 
being  the  substance,  of  which  the  spe- 
cula of  reflecting  telescopes  are  made. 
The  metal  required  for  this  purpose, 
ought  to  be  capable  of  an  exquisite  polish, 
hard  enough  to  receive  and  retain  a  fi- 
gure accurately  suited,  to  the  regular  re- 
flection of  light,  and  not  subject  to  be- 
come tarnished,  by  the  action  of  the  at- 
mosphere. Many  excellent  telescopes 
have  been  made  with  compositions  of  pure 
copper,  alloyed  with  somewhat  less  than 
half  its  weight  of  tin. 

But  it  appears  to  be  very  well  ascertain- 
ed, from  the  observations  of  the  English 
astronomer  royal,  that  the  specula  of  Mr. 
Edwards,  whose  composition  was  the  re- 
sult of  numerous  trials,  are  much  supe- 
rior to  any  which  have  yet  been  made, 
and  are  even  equal  in  light  to  achromatic 
telescopes  of  the  same  aperture,  without 
altering  the  colours  of  objects.  He  first 
melts  thirty-two  parts  of  copper  as  fluid 
as  possible,  with  one  part  of  brass,  and  one 
of  silver,  together  with  the  black  flux ; 
at  the  same  time  that  fifteen  parts  of  tin 
are  melted  in  a  separate  crucible.  These 
being  taken  from  the  fire,  he  pours  the 
tin  to  the  copper ;  immediately  stirs  the 
whole  together  with  a  wooden  spatula, 
and  pours  it  out  hastily  into  a  large  quan- 
tity of  cold  water,  which  cools  and  granu- 
lates the  composition.  If  the  tin  was  fused 
together  with  the  copper,  or  if  they  were 
to  remain  for  any  length  of  time  in  the 
extreme  heat  which  is  necessary  to  fuse 
this  last  metal,  a  part  of  the  tin  would  be 
oxided,  and  the  metal  would  abound  more 
or  less  with  small  microscopic  pores.  If 
one  of  the  pieces  of  the  cold  metal  be 
broken,  it  will  appear  a  most  beautiful 
bright  colour,  resembling  quicksilver. — 
Mr.  Edwards  affirms,  that  different  kinds 
of  copper,  require  different  doses  of  tin , 
to  produce  the  most  perfect  whiteness. 
If  the  dose  of  tin  be  too  small,  which  is 
the  fault  most  easily  remedied,  the  com- 
position will  be  yellowish  ;  if  it  be  too 
great,  the  composition  will  be  of  a  gray 
blue  colour,  and  dull  appearance.  He 
therefore  finds  by  trial,  the  quantity  of 
tin  necessary  to  be  added  in  the  second 
fusion,  to  render  the  metal  the  more  per- 


SPE 


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feet.  A  much  less  degree  of  heat  is  then 
required  to  melt  the  compound-  In  the 
second  melting"  he  adds  one  part  of  arse- 
nic, and  immediately  stirs  the  mixture  ; 
which  he  pours  into  the  mould  as  soon 
as  the  fumes  of  the  arsenic  have  ceased 
to  rise.  He  casts  the  speculum  in  sand, 
with  the  face  downwards ;  takes  it  out 
while  red-hot,  and  places  it  in  hot  wood 
ashes  to  cool :  without  which  precaution 
it  would  break  in  cooling. 

Mr.  Little  recommends  the  following 
proportions  :  32  parts  of  the  best  bar 
copper,  four  parts  of  the  brass  of  pin-wire, 
sixteen  and  a  half  of  tin,  and  one  and  a 
quarter  of  ai*senic.  Silver  he  rejects,  as 
it  has  an  extraordinary  effect  of  softening 
the  metal ;  and  he  found  that  the  com- 
pound was  not  susceptible  of  the  highest 
polish,  unless  it  was  extremely  brittle. 
He  first  melts  the  brass,  and  adds  to  it 
about  an  equal  weight  of  tin  When  this 
mixture  is  cold,  he  puts  it  into  the  cop- 
per, previously  fused  with  black  flux, 
adds  next  the  remainder  of  the  tin,  and 
lastly  the  arsenic.  This  mixture  he  gra- 
nulates, by  pouring  into  cold  water,  as  Mr. 
Edwards  did,  and  fuses  it  a  second  time 
for  casting. 

As  the  construction  of  telescopes  is  fo- 
reign to  the  immediate  purpose  of  this 
work,  it  has  not  been  thought  necessary 
to  mention  the  several  precautions  of  Mr. 
Edwards  in  this  business  ;  but  the  curious 
operator,  who  may  wish  to  undertake  the 
construction  of  a  reflecting  telescope, 
(the  better  kinds  of  which  are  not  only 
difficult  to  be  procured,  but  ol  consider- 
able price,)  may  have  recourse  to  Ed- 
wards's treatise,  annexed  to  the  Nautical 
Almanack  for  1787 ;  where  he  will  find 
ample  instructions  for  that  purpose.  He 
may  likewise  consult  the  Rev.  Mr.  James 
Little's  paper,  in  the  10th  volume  of  the 
Irish  Transactions. 

The  composition  of  metal  for  specu- 
la, previous  to  the  invention  of  the  re- 
flecting telescope,  was  in  the  hands  of  ar- 
tists, and  did  not  acquire  that  extreme 
perfection,  with  regard  to  density  and 
other  properties,  which  the  specula  of 
those  instruments  demand.  Experience 
showed  them,  that  arsenic  is  a  valuable 
ingredient  in  these  mixtures  ;  but  specu- 
lative philosophers,  reasoning  from  the 
saline  property  of  that  substance  before  it 
was  known,  that  it  can  be  reduced  to  a 
metal,  were  apprehensive  that  it  would 
increase  the  disposition  to  tarnish.  We  con- 
jecture, that  Mr.  Edwards's  composition 
might  be  improved,  by  a  greater  propor- 
tion of  arsenic,  or  at  least  by  adding  this 
ingredient  in  an  earlier  stage  of  the  pro- 
cess. For  this  reason,  we  shall  here  insert 


I  the  directions  which  Blancourt  in  his  Art 
of  Making  Glass,  gives  as  the  best  of  all 

j  compositions  for  whiteness,  hardness,  and 
susceptibility  of  an  exceeding  fine  polish. 
As  we  do  not  answer  for  the  value  of  this 
receipt, we  shall  give  it  in  the  author's  own 
words,  after  remarking,  that  the  oil  of 
tartar  is  evidently  unnecessary ;  that  the 
gradual  management  of  the  heat  on  a 
sand  bath,  is  probably  a  useful  refinement; 
that  the  substitution  of  orpiment  for  arse- 
nic, as  he  recommends,  must  be  noxious , 
that  by  latten  we  understand  common 
brass,of  which  there  are  various  kinds;  and 
that  the  addition  of  the  tin,should  be  made 
in  the  fused  state. 

Take  plates  of  copper,  one  pound, 
mince  them,  that  they  may  be  put  into  a 
crucible,  imbibing  them  wi"th  oil  of  tartar ; 
then  powder  a  quarter  of  a  pound  of  white 
arsenic,  and  put  these  stratum  super- 
stratum, until  you  fill  the  crucible  ;  pour 
on  them  afterwards  Unseed  oil,  to  cover 
the  arsenic  and  the  copper :  head  and  lute 
your  crucible ;  and  when  the  lute  is  dry 
set  it  on  a  sand  furnace,  letting  the  sand 
arise  no  higher  than  the  head  ;  heat  the 
furnace  gently,  till  it  arrives  at  a  just  de- 
gree, and  the  oil  begins  to  evaporate  ;  by 
this  time  the  oil  will  prepare  the  copper 
for  retaining  the  arsenic,  which  must  en- 
ter the  copper,  as  easily  as  oil  does  lea- 
ther ;  set  it  again  on  fresh  sand,  and  in- 
crease the  heat  of  the  furnace,  giving  it 
the  same  degree  as  before,  until  the  oil 
evaporates  and  boils  up ;  then  take  off 
the  crucible,  let  it  cool,  and  break  it,  you 
will  find  your  copper  of  several  colours. 
It  would  be  much  better,  if  instead  of  ar- 
senic, you  make  use  of  orpiment. 

Take  of  this  copper  one  part,  of  latten 
two  parts,  melt  the  latten  on  a  smart  fire, 
and  so  put  in  the  copper  ;  when  they  are 
well  melted,  cast  the  metal  drop  by  drop, 
into  a  glazed  earthen  vessel  full  of  water, 
over  which  lay  a  bush  or  broom  for  the 
stuff  to  go  through  ;  thus  you  will  have 
a  metal  not  to  be  touched  with  a  file,  nor 
brittle,  as  good  as  any  steel  for  all  uses 
whatever. 

Take  of  this  hard  metal,  three  parts, 
and  best  tin  of  Cornwall,  which  has  no 
lead  in  it,  one  part ;  melt  the  metal  be- 
fore you  put  in  the  tin :  after  these  are 
well  incorporated,  you  may  fill  your 
moulds,  8cc. 

SPELTER.  Zinc  is  called  spelter  in 
commerce.  The  soft  brass  containing  a 
redundant  proportion  of  zinc,  and  sold  in 
the  granulated  form  for  the  use  of  artists 
in  soldering,  is  called  spelter  solder,  and 
frequently  spelter  only. 

SPERMACETI.  This  peculiar  oily 
substance  is  found  abundantly  in  the  cra» 


SPI 

niumof  the  Cachalot  or  SpermacetiWhale, 
(Physeter  macrocephalus,  Linn.)  and  in 
some  other  species  of  the  same  genus  : 
but  though  containedin  thecavities  of  the 
scull,  it  appears  to  be  entirely  different 
from  the  proper  brain  of  the  animal.— 
When  first  extracted,  it  is  mixed  with  a 
considerable  quantity  of  oil  which  is  se- 
parated by  putting  the  mass  into  a  wool- 
len bag  and  pressing  it,  by  which  the 
greatest  part  of  the  oil  runs  out,  and 
then  washing  the  residue  with  a  warm 
weak  alkaline  ley,  which  dissolves  and. 
converts  into  soap  the  remainder  of  the  oil, 
leaving  behind  the  spermaceti  untouched; 
this  latter  alter  being  repeatedly  washed 
with  soft  water,  is  melted  by  a  very  gen- 
tle he  at,  the  impurities  partly  float  on  the 
surface,  and  partly  sink  to  the  bottom, 
and  are  thus  got  rid  of;  the  fluid,  in  ap- 
pearance a  perfectly  pellucid  oil,  is  now 
allowed  to  cool,  and  forms  on  congealing, 
a  mass  of  purified  spermaceti. 

Spermaceti  is  of  use  in  medicine,though 
chiefly  externally. 

Spermaceti  candles  are  of  modern  ma- 
nufacture :  they  are  made  smooth,  with 
a  fine  gloss,free  from  rings  and  scars,  su- 
perior to  the  finest  wax  candles,  in  colour 
and  lustre;  and,  when  genuine,  leave  no 
spot  or  stain  on  the  finest  silk,  cloth,  or 
linen. 

In  the  Transactions  of  the  Royal  Socie- 
ty of  London,  there  is  a  treatise  on  the 
conversion  of  animal  muscle,  into  a  sub- 
stance much  resembling  spermaceti.  It 
appears  from  a  number  of  experiments, 
that  if  flesh  is  exposed  to  the  action  of 
water  for  a  considerable  time,it  will  change 
it  into  a  fatty  substance  ;  which  discovery 
might  be  applied  to  profit,  for  making 
grease  or  fat  for  many  purposes.  The  ni- 
trous acid  greatly  accelerates  this  transfor- 
mation, and  takes  away  the  offensive  pu- 
trid smell.  By  submitting  it  to  the  ac- 
tion of  the  oxygenated  muriatic  acid,  the 
fermentation  goes  on  more  slowly,  but  it 
may  be  procured  quite  white  and  pure. 

SPINNING.  Spinning  is  applied  to 
the  reducing  of  silk,  flax,  hemp,  wool, 
hair,  &c.  into  thread,  and  is  usually  per- 
formed by  women. 

Spinning  by  hand  is  performed  either 
with  the  distaff  and  spindle,  or  on  the 
wheel :  in  the  former  case  the  person  sits 
to  her  work ;  in  the  latter  she  stands,  or 
rather  runs  backwards  and  forwards. 
We  shall  describe  both  methods.  When 
the  distaff  and  spindle  are  used,  the  flax 
or  other  substance  is  tied  or  fixed  on  a 
long  stick:  the  spinner  draws  out  a  thread, 
which  she  fixes  to  her  spindle  •  then  with 
her  left  hand  she  turns  the  wheel,  and 
with  her  right  guides  the  thread  drawn 
VOL.  II. 


SPI 

from  the  flax,  &c.  round  the  spindle,  or 
rather  round  a  spool  which  goes  on  the 
spindle.  When  a  sufficient  quantity  is 
wound  on  the  spool,  it  is  taken  off,  thrown 
into  the  basket,  and  replaced  by  an  empty 
one. 

Spinning  of  wool  is  managed  by  a  dif- 
ferent process.  Here  the  wool,  in  those 
fine  slivers  taken  from  the  wool-comber, 
is  held  fat  the  hand  ;  a  thread  of  it  is  fast- 
ened to  the  wheel,  which  the  spinner 
turns  with  velocity,  and  runs  backward 
from  it,  thereby  drawing  out  the  thread 
to  a  considerable  length.  In  either  mode 
of  spinning,  when  the  spindle  is  filled, 
its  thread  is  wound  upon  a  reel,  and  taken, 
off,  in  the  form  of  a  skain  or  hank.  The 
wool  is  delivered  out  to  the  spinner  by 
weight,  and  when  she  returns  it,  it  is  again 
weighed. 

Besides  the  above  mode  of  spinning 
wool  upon  the  wheel,  a  more  ancient  me- 
thod is  still  practised  with  the  distaff  and 
spindle,  which  may  be  used  either  sitting 
or  walking,  while  the  spinner  tends  on 
cows,  poultry,  &c.  The  sliver  of  wool  is 
braided  round  the  distaff  (or  rock  as  it  is. 
calledj)  from  the  slit  end  of  which  a  thread 
is  drawn  and  fastened  to  the  slender  spin- 
dle, which  receives  a  whirling  motion  by 
being  quickly  rolled,  upon  a  piece  of 
smooth  leather  called  the  trip-skin,  fast- 
ened upon  the  thigh  of  the  spinner,  who 
with  one  hand  gently  draws  a  few  hairs 
from  the  tail  of  the  sliver,  while  the  other 
winds  up  the  spindle,  and  renews  its 
whirling  motion.  In  this  way  finer  yarn  is 
made,  than  by  any  other  method,  but  more 
than  six  pence  a  day  can  seldom  be  earn- 
ed. 

Spinners  are  employed  by  the  master 
wool-combers.  Spinning  the  wool  into 
skains  is  the  first  process :  these  are  af- 
terwards put  into  the  hands  of  other  wo- 
men, called  winders,  whose  business  is, 
by  means  of  a  wheel  and  other  simple 
apparatus,  to  wind  two,  three,  or  more  of 
these  skains  together,  so  as  to  make  a 
compound  thread  of  them.  This  thread 
is  wound  on  to  spools  or  bobbins,  for  the 
convenience  of  having  them  fixed  on  spin- 
dles, which  are  turned  round  by  mill-work, 
in  order  to  twist  the  threads  thus  combin- 
ed into  a  firm  substance.  When  taken 
from  the  mill,  the  worsted  is  washed, 
dyed,  and  dried  ;  it  is  then  done  up  in 
crewels,  and  fit  for  sale. 

The  variety  and  importance  of  those 
branches  of  manufactures  which  are  pro- 
duced from  cotton,  wool,  and  flax,  spun 
into  yarn,  have  occasioned  many  attempts 
to  render  spinning  more  easy,  cheap,  and 
expeditious,  by  means  of  complicated 
machinery.  Several  of  these  have  been 
3  E 


SPI 


SPI 


very  successful ;  particularly  those  for 
cotton,  by  sir  Richard  Arkwright ;  but 
the  spinning-mill  has  not  as  yet  been  able, 
to  afford  worsted  yarn  so  cheap  as  that 
which  is  spun  by  hand. 

Mr.  Antis,  of  Fulneck,  near  Leeds,  in 
1793,  says  Dr.  Willich,  submitted  to  the 
inspection  of  the  Society  for  the  Encourage- 
ment of  Arts,  &c.  a  model  of  an  improved 
spinning-wheel ;  for  which  they  conferred 
on  him  a  bounty  of  20  guineas. 

The  usual  method  of  stopping  the  wheel, 
with  a  view  to  remove  the  yarn  from  one 
staple  on  the  flyer  to  another,  necessarily 
occasions  great  loss  of  time  ;  but,  in  Mr. 
Antis's  contrivance,  the  bobbin  is  so  ar- 
ranged, as  to  pass  backward  and  forward, 
in  order  to  prevent  any  interruption  j  and 
at  the  same  time,  to  obviate  both  the 
breaking  of  the  thread,and  losing  the  end : 
hence  the  spinner  is  enabled  to  perform 
more  work,  in  a  given  time,  than  is  prac- 
ticable by  any  other  spinning-wheel.  Such 
object  is  effected,  by  extending  the  axis 
of  the  great  wheel  through  the  pillar  next 
the  person  spinning  ;  and  forming  it  into 
a  pinion  of  one  leaf,  which  catches  into  a 
wheel,  seven  inches  in  diameter,  having 
on  its  periphery  97  teeth  ;  so  that  97  re- 
volutions of  the  great  wheel,  require  only 
one  of  the  smaller  wheel.  On  the  latter, 
a  wire-ring  is  fixed  :  which  being  sup- 
ported on  six  legs,  stands  obliquely  to  the 
wheel  itself ;  touching  it  at  one  part,  and 
projecting  nearly  three  quarters  of  an  inch 
at  the  opposite  edge.  Near  the '  side  of 
this  wheel,  is  an  upright  lever,  about  fif- 
teen inches  in  length,  moving  on  a  centre, 
three  inches  from  its  lower  extremity,  and 
connected  at  the  top  with  a  sliding  bar. 
From  such  bar  rises  an  upright  piece  of 
brass,  which  works  in  the  notch  of  a  pully, 
.and  drives  the  bobbin  to  and  fro,  during 
the  revolution  of  the  wheel. 

In  order  to  regulate  and  assist  the  al- 
ternate motion,  a  weight  is  suspended  by 
a  line  from  the  sliding-bar  ;  and  passing 
over  a  pulley,  it  rises  or  falls,  as  the  bob- 
bin advances  or  recedes ;  tending  con- 
stantly to  keep  the  pin  in  contact  with 
the  wire.  In  consequence  of  this  construc- 
tion, the  flyer  requires  only  one  staple  ; 
which,  being  fixed  near  its  extremity,  the 
Ihread  entering  through,  is  regularly  laid 
on  the  bobbin,  by  the  rotatory  motion  of 
the  latter. 

Since  Mr.  Antis  presented  the  model 
of  the  machine  here  described,  he  has 
made  several  alterations,  which  greatly 
contribute  to  its  perfection  ;  and  for  which 
the  Society  in  1795,  rewarded  him  with 
the  additional  sum  of  fifteen  guineas.  As 
we  conceive,  that  an  account  of  these  im- 
provements will  be  interesting  to  every 


industrious  house-wife,  we  shall  concisely 
state  them,  together  with  Mr.  Antis's  re- 
marks. 

1.  At  every  revolution  of  the  wheel,  in 
his  former  machine,  the  pinion  with  one 
leaf  occasioned  a  very  disagreeable  catch, 
while  the  bobbin  moved  only  by  jerks,  and 
did  not  receive  the  thread  in  an  uniform 
manner.  With  a  view  to  remedy  this  in- 
convenience, Mr.  Antis  has  adopted  the 
motion  of  an  endless  screw,  working  a 
toothed  wheel,  on  whioh  is  fixed  a  heart- 
shaped  piece  of  brass. 

2.  As  the  spinner  should  always  be  en- 
abled to  hold  the  thread  at  pleasure,  and 
not  let  it  in,  till  it  be  sufficiently  twisted, 
Mr.  Antis  observed,  that,  the  bobbin  mov- 
ing on  a  square,  its  motion  was  so  imped- 
ed, that  when  it  began  to  be  filled  with 
thread,  it  became  immoveable,  notwith- 
standing the  action  of  the  weight ;  and 
when  the  thread  was  afterwards  left  at 
liberty,  it  started  at  once  half  an  inch  and 
upwards. 

3.  As  in  the  wheels  of  the  common  con- 
struction, and  also  in  those  of  Mr  Antis's 
first  improvement,  the  friction  of  the  bob- 
bin could  be  augmented,  only  by  stretch- 
ing the  common  cord,  which  was  not 
practicable,  "without  making  the  wheel 
revolve,  with  increasing  difficulty,  parti- 
cularly when  the  bobbin  was  nearly  filled ; 
he  was  induced  to  make  use  of  a  single 
cord,  the  sole  design  of  which  is  to  turn 
the  flyer  ;  and,  in  case  it  should  become 
slack,  it  may  be  contracted  or  shortened, 
without  requiring  any  screw. 

Farther,  to  regulate  the  friction  of  the 
bobbin,  Mr.  Antis  has  fastened  a  neck  of 
steel,  or  brass  to  one  end,  which  is  kept 
steady  by  a  vice,  or  by  pincers,  fixed  to 
the  sliding-bar.  Such  vice  is  directed  to 
be  made  either  of  two  elastic  springs,  fur- 
nished with  wooden  tops ;  or  wholly  of 
wood  bushed  with  leather,  and  provided 
with  a  spring,  under  the  shoulder  of  the 
screw,  to  answer  the  same  purpose.  By 
tightening  this  screw  to  a  greater  or  less 
degree,  the  friction  may  be  most  accu- 
rately regulated,  without  impeding  the 
velocity  of  the  whole  ;  as  no  additional 
machinery  obstructs  the  general  motion. 
Mr.  Antis,  therefore,  concludes,  that  a 
wheel,  on  this  improved  plan,  will  be 
found  to  run  more  freely  than  those 
with  a  double  cord ;  a  circumstance 
of  the  greatest  importance,  to  a  person 
whose  daily  livelihood  is  obtained  by  spin- 
ning: nay,  even  a  lady  who  sometimes 
spins  for  "her  diversion,  was  much  pleased 
with  his  first  invention,  and  thought  it 
might  save  a  person  at  least  two  hours  in 
a  day.  He  observes,  that  his  contrivance 
may  be  added  to  old  spinning  wheels,  of 


SPI 


<°yery  construction  ;  and  that  it  would  not 
considerably  increase  the  price  of  a  new 
machine,  made  according  to  his  plan- 
It  would  take  up  too  much  of  our  work, 
to  give  an  explanation  of  the  various  im- 
provements of  Mr.  Arkwright,  in  spin- 
ning machinery:  some  of  which,  however, 
have  been  given  in  the  article  on  M  a  n  r  - 
factures.  The  subject  has  been  much 
attended  to  in  this  country,  and  been  pro- 
ductive of  considerable  advantages  ;  for 
labour-saving  machinery,  especially  when 
labour  is  high,  will  always  be  useful  in  a 
country  like  this. 

We  might  enumerate  the  names  of  ma- 
ny, who,  with  patriotism  and  zeal  for  the 
encouragement  of  manufactures,  have 
added  considerably  to  this  important  en- 
deavour. Spinning  machinery  either  to 
go  by  hand,  water  or  other  power,  to  turn 
from  ten  to  a  thousand  spindles,  have 
been  erected  in  almost  every  quarter  of 
the  union.  The  portable  machine  of  J.  G. 
Baxter,  which  may  be  seen  at  No.  5,  Ap- 
ple-tree alley,  belonging  to  the  Female 
Hospitable  Society,  Philadelphia,  which 
works  by  hand,  will  turn  from  ten  spin- 
dles to  any  number  found  necessary.  That 
of  Dr.  Allison  of  Bordentown, New-Jersey, 
is  highly  approved ;  and  the  late  and  la- 
mented J.  Beers,  Esq.  of  Holmesville, 
Bucks  county,  Pennsylvania,  who  improv- 
ed spinning  machinery  very  considerably, 
and  was  well  known  as  a  manufacturer, 
is  among  the  number  to  whom  our  coun- 
try is  most  indebted.  The  spinning  ma- 
chinery of  Craig  &  Marquedant,  erected 
in  the  vicinity  of  this  city,  which  gives 
employment  in  the  different  branches  of 
the  work,  to  a  large  number  of  females, 
also  exhibits  the  genius  and  zeal  of  our 
countrymen.  See  Manufacture  of 
Cotton. 

SPIRIT. — This  name  was  formerly  giv- 
en by  chemists  to  all  volatile  substances 
collected  by  distillation.  Three  principal 
kinds  were  distinguished:  inflammable  or 
ardent  spirits,  acid  spirits,  and  alkaline 
spirits.  In  the  first  class-were  included 
not  only  the  product  known  by  the  com- 
mon name  of  spirit  of  wine,  and  its  com- 
pounds, but  the  light  volatile  oils,  ethers, 
and  the  aromatic  principle.  The  subjects 
of  the  latter  class  need  no  enumeration. 

The  word  spirit  is  now  almost  exclu- 
sively confined  to  alcohol  5  and  the  other 
substances  formerly  arranged  under  the 
classes  here  mentioned,  are  distinguished 
respectively  by  their  peculiar  names,  with- 
out reference  to  any  general  arrangement 
grounded  on  a  property  of  so  indistinct  a 
nature  as  that  of  their  being  separated 
from  other  bodies  by  distillation.  See  Al- 
cohol* 


Spirit  may  be  produced  from  a  variety 
of  substances,  after  fermentation,  by  dis- 
tillation ;  such  spirits  are  said  to  be  distil- 
led. Fruits,  roots,  and  vegetables  of  va- 
rious kinds,  principally  such  as  contain 
much  saccharine  matter,  in  which  the 
United  States  abound,  are  employed  in 
this  country  for  the  purpose.  What  is 
called  apple  brandy,  or  cyder  spirits,  of 
which  some  notice  has  already  been  tak- 
en, is  made  in  considerable  quantities. 
The  apples  are  mostly  taken  to  the  distil- 
lery, where  they  are  exchanged  for  spi- 
rit, in  the  proportion  of  five  bushels  to 
one  gallon  of  liquor.  The  apples  are  ope- 
rated on  and  expressed,  in  the  usual  man- 
ner ;  the  cyder  is  afterwards  fermented  in 
large  cisterns,  or  vats,  and  in  6  or  8  days, 
according  to  the  weather,  is  fit  for'  the 
still.  The  pumice,  after  expression,  is 
preserved  in  some  distilleries,  where  it  is 
treated  with  water,  fermented,  the  liquor 
pressed  out,  and  distilled.  In  Lancaster 
county,  in  this  state,  it  is  customary  to 
grind  the  apples,  ferment  the  pumice  thus 
formed,  and  commit  the  whole  to  distilla- 
tion. Some  difference  is  said  to  be  made 
In  the  spirit  obtained  from  apples ;  one 
kind  is  called  apple  brandy,  and  the  other 
apple  spirit,  which  distinction,  however, 
is  seldom  made,  the  whole  being  sold  as 
apple  whiskey.  The  spirit  obtained  from 
peaches,  which  is  done  in  the  same  man- 
ner as  apples  are  treated,  is  called  peach 
liquor,  or  peach  brandy.  This  spirit  is 
said  to  be  improved  by  bruising  the  ker- 
nels, and  distilling  them  with  the  ferment- 
ed juice. 

Cherries  and  fox-grapes, expressed,  and 
the  juice  fermented  and  distilled,  will  af- 
ford agreeable  liquor.  The  former,  how- 
ever, are  more  generallj  made  into  a  li- 
quor called  bounce.  The  latter,  if  pro- 
perly treated,  yield  a  spirit  not  inferior  to 
Cogniac  brandy.  To  imitate  this,  let  them 
be  mashed,  and  after  standing  a  day  or 
two,  the  juice  must  be  expressed  and  fer- 
mented as  with  peaches,  and  the  ferment- 
ed liquor  then  distilled.  From  potatoes 
a  spirit  is  obtained  of  a  good  quality.  Ac- 
cording to  Bertrand,  600  lbs.  of  potatoes 
are  boiled,  and  reduced  to  a  mash  with 
hot  water,  till  they  are  of  a  liquid  consis- 
tence,, and  mixed  with  25  lbs.  of  ground 
malt,  and  two  quarts  of  yeast ;  the  mix- 
ture is  to  be  stirred,  covered  with  a  cloth, 
and  kept  to  the  temperature  of  66°  of 
Fahrenheit  After  fermentation,  the  mat- 
ter sinks  down,  and  is  fit  for  distillation. 
Two  stills  will  distil  this  matter  in  one 
day ;  and  the  spirit  produced  will  amount 
to  44  quarts.  The  residue  is  fit  for  hogs. 
The  process  for  procuring  spirit  from  po- 
tatoes has  been  more  or  less  varied.. 


SPR 


STA 


Beets,  as  they  afford  much  sugar,  will  al- 
so produce  much  spirit  by  fermentation 
and  distillation.  The  distillation  of  fer- 
mented beetroots  has  not,  however,  been 
yet  attempted.  In  France,  sugar  is  ob- 
tained from  them. 

An  union  of  rye  and  corn  in  mashing-, 
will,  it  is  said,  produce  more  spirit  than 
can  be  procured  from  either  grain  alone. 
Corn  is  seldom,  if  ever,  used  alone. 
Wheat,  although  not  used,  will  yield  more 
spirit  than  rye,  in  the  proportion  of  six  to 
five 

Three  gallons  of  spirits  may  be  procur- 
ed from  60  lbs.  of  oats ;  but  a  mixture  of 
one-third  of  oats,  and  two-thirds  of  corn, 
will  afford  a  better  liquor.  Other  grains 
will  yield  spirit  in  different  proportions, 
and  more  or  less  good.  See  Alcohol, 
Gin,  Brandy,  Distillation,  &c. 

SPIRIT  OF  WINE.    See  Alcohol. 

SPIRITUOUS  LIQUORS,  to  try.  See 
Alcohol  and  Hydrometer. 

SPIRIT  OF  NITRE.  See  Nitric 
Acid. 

SPIRIT  OF  SALT.  See  Muriatic 
Acid. 

SPIKE  OIL.    See  Oil. 

SPRUCE,  Essence  of  is  an  extract  pre- 
pared from  the  canes,  twigs,  or  sprouts, 
of  the  spruce  fir.  It  is  used  only  in  pre- 
paring beer,  according  to  the  following 
process : 

SPRUCE  BEER,  to.make—  Eight  gal- 
lons of  water  are  first  poured  into  a  cask, 
or  other  vessel ;  and  a  similar  quantity  of 
boiling  water  is  added;  16  lbs  of  mo- 
lasses are  next  mixed,  together  with  a 
few  table-spoonfuls  of  the  essence  of  spruce. 
Half  a  pint  of  sweet  yeast  must  now  be 
put  in  ;  and  the  whole,  after  being  well 
stirred,  should  be  placed  in  a  temperate 
room,  for  a  few  days,  till  the  fermentation 
ceases.  The  liquor  may  then  be  bottled  ; 
and,  in  the  course  of  a  fortnight,  it  will  be 
fit  for  use. 

This  process  is  varied  sometimes.  The 
following  receipt  is  said  to  be  preferable. 

To  a  four  ounce  pot  of  essence  of 
spruce,  add  three  quarts  of  molasses,  two 
gallons  of  warm  rain  or  soft-water,  and 
half  a  pint  of  good  yeast.  Stir  the  whole 
well,  till  the  liquor  bears  a  froth,  then 
put  the  mixture  into  a  cask,  and  fill  it  with 
eight  gallons  of  water,  shaking  it  well ; 
set  it  by  for  two  or  three  days,  to  ferment, 
with  the  bung  open ;  when  sufficiently 
worked,  bung  the  cask  close,  and  place 
it  in  a  cool  cellar,  and  in  24  hours  it  will 
be  fit  for  use... .If  intended  for  bottling,  let 
the  cask  stand  undisturbed  three  clays  be- 
fore it  is  drawn  off :  for  a  second  brew- 
ing, the  sediment  remaining  in  the  cask 
may  be  used  instead  of  yeast.   If  well- 


water  be  used,  it  should  be  a  little 
warmed. 

The  Dantzig  spruce  beer  is  reckoned 
the  best ;  the  taste  of  the  American 
spruce  is  less  agreeable. 

S!  UR  WHEEL.  See  Mechanics 
STAINS,  how  removed. — To  remove  ink 
stains... .The  stains  of  ink  on  cloth,  paper, 
or  wood,  may  be  removed  by  almost  all 
acids  ;  but  those  acids  are  to  be  preferred 
which  are  least  likely  to  injure  the  tex- 
ture of  the  stained  substance.  The  mu- 
riatic acid,  diluted  with  five  or  six  times 
its  weight  of  water,  may  be  applied  to  the 
spot,  and,  after  a  minute  or  two,  may  be 
washed  off,  repeating  the  application  as 
often  as  may  be  found  necessary.  But  the 
vegetable  acids  are  attended  with  less 
risk,  and  are  equally  effectual.  A  solu- 
tion of  the  oxalic,  citric  (acid  of  lemons), 
or  tartareous  acids,  in  water,  may  be  ap- 
plied to  the  most  delicate  fabrics  without 
any  danger  of  injuring  them;  and  the 
same  solutions  will  discharge  writing, 
but  not  printing  ink.  Hence  they  may  be 
employed  in  cleaning  books  which  have 
been  defaced  by  writing  on  the  margin, 
without  impairing  the  text.  Lemon-juice, 
and  the  juice  of  sorrels,  will  also  remove 
ink  stains,  but  not  so  easily  as  the  con- 
crete acid  of  lemons  or  citric  acid. 

To  remove  Iron  Stains. 
These  maybe  occasioned  either  by  ink 
stains,  which,  on  the  application  of  the 
soap,  are  changed  into  iron  stains,  or  by 
the  direct  contact  of  rusted  iron.  They 
may  be  removed  by  diluted  muriatic  acid, 
or  by  one  of  the  vegetable  acids  already 
mentioned.  When  suffered  to  remain 
long  on  cloth,  they  become  extremely  dif- 
ficult to  take  out,  because  the  iron,  by  re- 
peated moistening  with  water,  and  expo- 
sure to  the  air,  acquires  such  an  addition 
of  oxigen,  as  renders  it  insoluble  in  acids. 
It  has  been  found,  however,  that  even 
these  spots  may  be  discharged,  by  apply- 
ing first  a  solution  of  an  alkaline  sulphu- 
ret,  which  must  be  well  washed  from  the 
cloth,  and  afterwards  a  liquid  acid.  The 
sulphuret,  in  this  case,  extracts  part  of 
the  oxigen  from  the  iron,  and  renders  it 
soluble  in  diluted  acids. 

To  remove  the  Stains  of  Fruit  and  Wine. 

These  are  best  removed  by  a  watery 
solution  of  the  oxigenated  muriatic  acid, 
or  by  that  of  oxigenated  muriat  of  potash 
or  lime,  to  which  a  little  sulphuric  acid 
has  been  added.  The  stained  spot  may 
be  steeped  in  one  of  these  solutions  till  it 
is  discharged  ;  but  the  solution  can  only 
be  applied  with  safety  to  white  goods,  be- 
cause the  uncombined  oxigenated  acid 


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discharges  all  printed  and  dyed  colours. 
A  convenient  mode  of  applying  the  oxi- 
genated  acid,  easily  practicable  by  per- 
sons who  have  not  the  apparatus  for  satu- 
rating1 water  with  the  gas,  is  as  follows  : 
Put  about  a  table-spoonful  ot  muriatic 
acid  (spirit  of  salt)  into  a  tea-cup,  and 
add  to  it  about  a  tea  spoonful  of  powder- 
ed manganese;  then  set  this  cup  in  a 
larger  one  filled  with  hot-water ;  moisten 
the  stained  spot  with  water,  and  expose  it 
to  the  fumes  that  arise  from  the  tea-cup. 
If  the  exposure  be  continued  a  sufficient 
length  of  time,  the  stain  will  disappear. 

To  remove  Spots  of  Grease  from  Cloth. 
Spots  of  grease  may  be  removed  by  a 
diluted  solution  of  potash,  but  this  must 
be  cautiously  applied,  to  prevent  injury  to 
the  cloth.  Stains  of  white  wax,  which 
sometimes  fall  upon  the  clothes  from  wax 
candles,  are  removable  by  spirits  of  tur- 
pentine, or  sulphuric  ether.  The  marks 
of  white  paint  may  also  be  discharged  by 
the  last  mentioned  agents. 

To  take  Spots  of  Grease  out  of  Books, 
Prints,  or  Paper. 
After  having  gently  warmed  the  paper 
that  is  stained  with  grease,  wax,  oil,  or 
any  other  fat  body,  take  out  as  much  as 
possible  of  it  by  means  of  blotting  paper  ; 
then  dip  a  small  brush  in  the  essential  oil 
of  turpentine,  heated  almost  to  ebullition 
(for  when  cold  it  acts  only  very  weakly), 
and  draw  it  gently  over  both  sides  of  the 
paper,  which  must  be  carefully  kept  warm. 
This  operation  must  be  repeated  as  many 
times  as  the  quantity  of  the  fat  body  im- 
bibed by  the  paper,  or  the  thickness  of 
the  paper,  may  render  necessary.  When 
the  greasy  substance  is  entirely  removed, 
recourse  may  be  had  to  the  following  me- 
thod to  restore  the  paper  to  its  former 
whiteness,  which  is  not  completely  restor- 
ed by  the  first  process.  Dip  another 
brush  in  highly  rectified  spirit  of  wine, 
and  draw  it  in  like  manner  over  the  place 
which  was  stained,  and  particularly  round 
the  edges,  to  remove  the  border  that 
would  still  present  a  stain.  By  employing 
these  means  with  proper  caution,  the  spot 
will  totally  disappear,  the  paper  will  re- 
sume its  original  whiteness,  and  if  the 
process  has  been  employed  on  a  part 
written  on  with  common  ink,  or  printed 
with  printers  ink,  it  will  experience  no  al- 
teration. 

STAINING  OF  WOOD,  how  perform- 
ed.    See  Dyeing. 

STARCH.— We  shall  in  this  place  men- 
tion the  mode  of  manufacturing  the  com- 
mon starch  which  is  made,  for  sale,  al- 
most exclusively  from  wheat.  This  grain 


consists  of  gluten,  fecula,  a  colouring  ex- 
tractive matter,  and  phosphat  of  lime, 
and  it  is  the  object  of  the  starch-maker, 
to  separate  the  fecula  alone  from  all  the 
other  ingredients.  This  might  be  done, 
one  would  think,  simply,  as  the  arrow  root 
starch  is  made  in  the  West  Indies,  by 
gr  inding  the  wheat  into  very  fine  flour,  mix- 
ing the  Hour  with  water  into  a  stiff'  paste 
witli  much  beating,  and  then  exposing  this 
pabte  with  uninterrupted  agitation  to  a 
gentle  current  of  pure  water,  which  would 
run  off'  milky  with  the  starch  as  long  as 
any  of  it  remained  in  the  paste,  and  the 
gluten  alone  would  be  left  behind.  This 
milky  water  would  deposit  the  starch  by 
remaining  at  rest  for  a  time. 

A  similar  method  is  followed  in  the 
small  way  in  making  potatoe  starch,  as 
mentioned  under  the  article  fecula,  only 
with  less  labour,  as  this  contains  no  glu- 
ten. 

Wlieat  starch  is  not  made,  however, 
exactly  in  this  simple  way,  but  the  grain, 
after  being  coarsely  ground,  is  suffered  to 
ferment  or  mould  with  water  for  many 
days,  by  which  its  texture  is  entirely  bro- 
ken down,  and  the  starch,  which  is  scarce- 
ly alterable  in  the  process,  is  probably 
more  effectually  separated  from  all  the 
other  ingredients,  and  obtained  finer  and 
whiter.  The  actual  method  is  (in  a  few 
words)  the  following  :  The  wheat  is  aarst 
coarsely  bruised,  and  placed  in  large 
wooden  vats  or  reservoirs,  water-tight, 
and  intimately  mixed  with  water.  Here 
a  fermentation  begins  after  a  time,  which 
is  a  mixture  of  the  vinous  and  acetous, 
and  is  attended  with  a  strong,  unpleasant, 
sour,  mouldy  smell.  The  wheat  remains 
in  the  vat  for  about  a  fortnight,  till  the 
fermentation  ceases,  which  is  known  by 
its  settling  at  the  bottom  of  the  vat.  The 
contents  are  then  emptied  successively 
into  a  small  tub,  and  mixed  with  fresh  wa- 
ter, till  all  the  pulpy  part  is  thin  enough 
to  pass  through  a  hair  . sieve,  which  sepa- 
rates the  bran  from  it.  What  has  gone 
through  contains  the  starch  suspended  h. 
a  very  sour  water,  and  considerably  foui. 
This  is  put  into  tubs  or  frames,  and  al- 
lowed to  remain  for  two  days  undisturb- 
ed, during  which  the  impure  starch  set- 
tles to  the  bottom.  The  water  is  then 
drawn  off,  the  frames  turned  on  their 
sides,  and  the  dirty  discoloured  part  of 
the  starch  (which  is  the  last  that  sub- 
sides, and  therefore  is  at  the  top)  is  scrap- 
ed off*,  and  the  remaining  starch  is  well 
washed  and  brushed,  till  it  is  nearly  free 
from  this  muddy  sediment,  which  is  call- 
ed slimes,  and  is  treated  separately  to  ob- 
tain its  starch.  The  starch  is  stirred  with 
fresh  water,  and  suffered  to  settle,  and 


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again  cleansed,  till  all  its  impurities  are 
removed,  and  is  then  mixed  with  water 
enough  to  make  it  liquid,  and  passed 
through  a  fine  lawn  sieve.  It  is  then  fit 
to  receive  its  colour,  which  consists  of 
smalt  mixed  with  water  and  a  small  quan- 
tity of  alum,  and  is  thoroughly  incorpo- 
rated with  the  starch.  After  again  set- 
tling, the  starch  is  taken  out  and  put  into 
oblbng  boxes,  about  six  feet  long  and  one 
broad,  with  holes  at  the  bottom,  and  lined 
with  linen  cloth,  where  the  moisture  of 
the  starch  drains  off  till  it  becomes  solid 
enough  to  be  cut  into  square  lumps. 
These  are  laid  on  new  bricks,  which  ab- 
sorb much  of  their  moisture,  and  make 
them  hard  enough  to  be  stoved.  Here 
the  starch  remains  in  a  moderate  heat, 
till  a  slimy  crust  rises  to  the  surface, 
which  is  carefully  scraped  oft",  and  the 
rest,  which  is  now  perfectly  pure  starch, 
is  papered  and  placed  again  in  the  stove 
with  a  good  hot  fire,  till  quite  dry.  This 
last  stoving  causes  the  lumps  to  crack 
pretty  uniformly  into  the  small  pieces  in 
which  they  appear  when  sold.  The  slimes 
are  all  treated  in  the  same  way  till  alt  the 
starch  is  got  from  them.  All  the  refuse 
matter  from  starch  making  makes  very 
valuable  food  for  fattening  hogs.  The 
whole  time  of  making  starch,  from  the 
first  steeping  of  the  wheat  to  the  last  stov- 
ing, is  about  six  weeks ;  and  551  Win- 
chester bushels  of  wheat  will  make  about 
six  ton  of  starch.  This  will  be  about  7-17 
of  the  entire  weight  of  the  wheat. 

In  the  process  of  starch-making  a  great 
quantity  of  a  sour  nauseous  milky  water 
is  obtained,  from  which  the  starch  sub- 
sides after  it  is  first  removed  from  the 
fermenting  vat. 

The  starch-sours  contain,  besides  a  vi- 
sible white  matter  separable  by  filtering, 
a  quantity  of  phosphat  of  lime  and  am- 
monia, both  held  in  solution  by  the  ace- 
tous acid  which  is  generated  so  abun- 
dantly by  the  fermentation.  A  peculiar 
animal  matter  is  also  found  in  this  acid  li- 
quor, which  seems  to  resemble  gluten, 
and  therefore  only  belongs  to  that  starch 
which  is  made  from  wheat  flour. 

This  liquor  therefore  contains  the  five 
following  substances,  viz.  acetous  acid, 
ammonia,  alcohol,  gluten,  and  phosphat 
of  lime,  but  of  these  only  the  two  last  are 
natural  to  the  wheat ;  the  others  are  the 
products  of  the  fermentation,  the  ammo- 
nia being  generated  by  the  decomposition 
of  part  of  the  gluten,  the  alcohol  by  the 
saccharine  mucilage  which  all  grain  con- 
tains, and  the  acetous  acid  perhaps  from 
all  the  other  principles.  The  peculiar  of- 
fice which  this  acid  performs  in  starch- 
making  is  to  dissolve  the  gluten  and  phos- 


phat of  lime,  and  thus  to  separate  them 
from  the  pure  starch.  Hence,  when  wheat 
is  the  grain  employed,  arises  the  necessi- 
ty of  continuing  the  fermentation  long 
enough  to  generate  a  sufficient  quantity 
of  acetous  acid  ;  for  the  other  grains  and 
roots  which  yield  starch,  contain  little  or 
no  gluten.  A  considerable  quantity,  how- 
ever, of  the  starch  must  be  destroyed  in 
the  process,  for  wheat  contains  much  more 
of  it  than  is  obtained  in  manufacture,  as 
may  be  found  by  washing  flour  paste  with 
water  in  the  way  mentioned  in  the  begin- 
ning of  this  article. 

According  to  Parmentier,  the  roots  of 
twenty-two  vegetables  yield  starch,  and 
the  seeds  of  nine  plants  and  trees  con- 
tain it  nearly  pure.  The  Indian  turnip 
also  produces  it.  Dry  mealy  potatoes  af- 
ford a  large  proportion  of  starch.  Baume 
gives  the  following  method : 

Take  clean  mashed  potatoes,  collect  the 
pulp  in  a  tub,  and  mix  it  with  a  great 
quantity  of  clean  water.  Place  two  wood- 
en rails  on  the  brim  of  another  very  clean 
tub  to  support  a  sieve,  which  must  not  be 
too  fine.  Throw  the  pulp  and  water  into 
the  sieve ;  pour  fresh  quantities  of  water 
on  the  pulp,  till  the  clear  water  runs 
through.  In  six  hours  the  water  will  have 
deposited  the  flour  suspended  in  it ;  when 
the  water  is  to  be  poured  off,  and  a  great 
quantity  of  very  clean  water  poured  upon 
the  flour  remaining  at  the  bottom  of  the 
tub,  which  is  to  be  stirred  up  in  the  wa- 
ter, and  the  whole  is  to  stand  quiet  till  the 
day  following.  The  flour  will  then  be 
found  to  have  settled  at  the  bottom  of  the 
tub  :  the  water  is  again  to  be  poured  off ; 
the  flour  washed  in  a  fresh  quantity  of 
pure  water,  and  the  mixture  passed 
through  a  silk  sieve  pretty  fine.  The 
whole  must  once  more  be  suffered  to 
stand  quiet  till  the  flour  is  settled,  if  the 
water  above  it  is  clean,  and  the  flour  has 
been  sufficiently  washed ;  but  if  the  wa- 
ter has  any  colour,  it  must  be  again 
washed. 

When  perfectly  washed,  take  out  the 
flour,  and  place  it  upon  wicker  frames  co- 
vered with  paper,  and  dry  it,  properly  de- 
fending it  from  the  dust.  When  dried, 
pass  it  through  silk  sieves,  to  divide  any 
clotted  lumps  that  may  remain  ;  and  keep 
it  in  glass  vessels  stopped  with  paper 
only. 

The  following  is  the  method  adopted 
by  a  Mrs.  Gibbs,  for  preparing  starch 
from  the  roots  of  the  Wake-Robin ;  for 
which  the  Society  for  the  Encouragement 
of  Arts,  &c.  in  1797,  presented  her  with 
their  gold  medal.  She  observes,  in  her 
communication,  that  such  roots  are  found 
in  the  Isle  of  Portland,  in  the  common 


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fields,  whence  they  may  be  dug  out, 
cleansed,  and  pounded  in  a  stone  mortar 
with  water.  The  whole  is  then  strained, 
and  the  starch  settles  at  the  bottom :  a 
peck  of  these  roots  produced,  upon  an 
average,  about  four  pounds  of  starch, 
whicli  was  sold  at  Hd  per  pound. 

Good  starch,  when  dry,  is  pulverulent, 
tasteless,  without  odour,  insoluble  both  in 
cold  water  and  ardent  spirit :  on  the  ad- 
dition of  boiling  water,  however,  it  forms 
Paste,  or  Pastry,  of  which  the  reader  will 
find  an  account.  ..It  is  one  of  the  constitu- 
ent parts  in  all  mealy  or  farinaceous 
seeds,  fruits,  roots,  Sec. "of  plants  ;  though 
some  vegetables  contain  a  much  larger 
proportion  of  it  than  others.  Thus,  the 
Wake-Robin,  and  White  Bryony,  afford 
more  starch  than  potatoes ;  and  the  Sa- 
lep-roots,  especially  those  of  the  Mea- 
dow- Orchis,  for  the  greatest  part,  consist 
of  that  valuable  substance 

Starch  being  the  basis  of  hair-powder, 
and  also  of  extensive  utility  for  domestic 
purposes,  various  experiments  have  been 
instituted,  with  a  view  to  ascertain  such 
vegetables  as  might  be  advantageously 
substituted  for  wheat. 

STATER  A,  ROMAN.  See  Mecha- 
nics 

STEAM,  is  water  in  the  state  of  va- 
pour, produced  by  ebullition,  or  a  tempe- 
rature of  212  degrees  of  heat.  It  is  ap- 
plied to  various  purposes,  and  is  more 
particularly  useful  as  a  moving  power,  in 
what  is  called  the  steam  engine.  The 
conversion  of  water  into  steam  is  owing 
to  its  combination  with  the  matter  of 
heat,  and  that  of  steam  to  the  state  of 
water  to  the  abstraction  of  heat'  by  a 
colder  medium. 

Steam  may  be  employed  in  domestic 
economy,  and  particularly  in  cooking 
Thus,  steamed  potatoes  are  always  more 
wholesome  and  nutritious,  than  such  as 
are  boiled  in  water ;  and  Dr.  Darwin  ob- 
serves, that  if  the  heat  of  the  steam  could 
be  increased  after  it  has  left  the  water, 
the  art  of  boiling  all  vegetables  might  be 
considerably  improved  ;  and  thus  the  mu- 
cilage, abounding  both  in  potatoes  and 
flour  puddings,  and  also  in  the  roots, 
seeds,  stems,  leaves,  and  flower-cups  of 
plants,  may  be  rendered  more  nutritive, 
and,  probably,  more  palatable.  See 
Steam  Engine. 

STEAM  DISH. — This  very  useful  con- 
trivance is  described  in  the  Repertory  of 
Arts,  vol.  4,  and  in  the  Domestic  Encyclo- 
pedia, vol.  5.  It  is  made  of  tin,  or  earthen- 
ware, (for  a  family  of  six  or  eight)  twelve 
inches  by  nine,  at  the  top,  and  nine  by  se- 
ven, at  the  bottom,  four  and  a  half  inches 
deep,  on  the  slant  rim,  and  three  inches, 


in  the  clear,  under  four  resting  knobs,  (a 
little  below  the  top,)  which  space  is  to  be 
occupied  by  the  meat  of  which  the  pastry 
is  made. 

STEAM  STOVE.— In  a  late  improve- 
ment made  to  the  common  stove,  by  Mr. 
Abbot  of  this  city,  a  tin  vessel  may  be  so 
applied  as  to  boil  or  bake  by  means  of 
steam.  This  stove  is  indeed  superior  to 
all  others,  as  it  may  be  used  for  boiling, 
baking,  &c  at  the  same  time,  and  con- 
sumes a  le  ss  quantity  of  fuel.  The  price 
is  from  <g30  to  $35,  according  to  the  size. 

STEAM  ENGINE. — The  steam  engine 
is  one  of  the  noblest  monuments  of  hu- 
man ingenuity.  It  was  originally  invent- 
ed by  the  Marquis  of  Worcester,  in  the 
reign  of  Charles  II.  This  nobleman,  who 
appears  to  have  been  possessed  of  much 
knowledge,  with  a  fertile  imagination, 
published  in  1663,  a  small  book,  called 
"  A  Century  of  Inventions,"  giving  an  ac- 
count of  an  hundred  discoveries  or  con- 
trivances of  his  own  ;  but  the  descriptions 
of  many  of  them  are  so  obscure,  that  they 
are  altogether  unintelligible. 

Among  them  is  an  account  of  his  inven- 
tion of  raising  water  by  the  force  of  steam, 
which,  now  that  we  are  possessed  of  the 
engine,  appears  to  agree  very  well  with 
its  construction.  But  as  there  is  no  plate 
to  accompany  his  description,  we  are  en* 
tirely  unacquainted  with  the  particular 
mode  in  which  he  applied  the  power  of 
steam.  It  does  not  appear,  however,  that 
he  met  with  sufficient  encouragement ; 
and  this  useful  discovery  was  long  ne- 
glected. 

Towards  the  end  of  the  century.  Cap- 
tain Savary,  a  person  of  great  ingenuity, 
havirfg  probably  seen  the  account  of  the 
Marquis  of  Worcester's  invention,  was 
convinced  of  its  practicability,  and  suc- 
ceeded in  constructing  a  machine  of  this 
kind  lie  obtained  a  patent  for  the  inven- 
tion, and  erected  several  steam  engines, 
which  he  described  in  a  book,  entitled, 
"  The  Miner's  Friend,"  published  in  1696. 

The  following  is  the  description  of  his 
machine,  as  improved  by  himself : 

a  (Plate  XVIII,  fig  1 .)  is  a  strong  boiler, 
built  in  a  furnace  for  generating  steam. 
From  the  top  of  this  boiler  there  proceeds 
a  pipe,  b,  which  conveys  the  steam  into 
another  strong  vessel,  r,  called  the  re- 
ceiver This  pipe  has  a  cock  at  c,  called 
the  steam-cock.  In  the  bottom  of  the  re- 
ceiver is  a  pipe,  S,  which  communicates 
with  the  rising-pipe  II  n  k,  the  lower  end 
of  which  is  immersed  in  the  well  from 
which  the  water  is  to  be  raised.  Imme- 
diately below  the  place  where  the  pipe  S 
enters  the  rising-pipe,  there  is  a  valve,  n, 
opening  upwards.   A  similar  valve  is  also 


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STE 


placed  at  r,  above  the  pipe  S.  Lastly,  there 
is  a  pipe,  e,  which  branching-  off  from  the 
rising-pipe,  enters  the  top  of  the  receiver. 
This  pipe  has  also  a  cock,  d,  called  the 
injection.cock.  The  mouth  of  the  pipe  e, 
has  on  the  end  f  a  nozzle,  pierced  full  of 
holes,  pointing  from  a  centre  in  every  di- 
rection. The  keys  of  the  two  cocks  c  and 
</,  are  united  by  the  handle  h,  called  the 
regulator. 

The  mode  of  operation  is  as  follows  : 
Let  the  regulator  be  so  placed,  that  the 
steam-cock  c  be  open,  and  the  injection- 
cock  d  shut ;  put  water  into  the  boiler  a, 
and  make  it  boil.  The  steam  from  it  will 
enter  the  pipe  6,  and  fill  the  receiver,  first 
driving  out  the  air  which  it  before  con- 
tained ;  a  considerable  quantity  of  steam 
will  be  at  first  condensed  by  the  cold 
sides  of  the  receiver,  but  it  being  at  length 
warmed,  the  steam  will  proceed  into  the 
rising-pipe,  lifting  up  the  valve  i.  When 
this  is  perceived  to  be  the  case,  by  the 
rising-pipe  feeling  warm,  and  hearing  the 
valve  i  rattle,  the  communication  is  now 
to  be  cut  off  from  the  boiler,  by  shutting 
the  steam-cock  c,  the  injection -cock  d, 
being  also  shut.  The  receiver  now  gra- 
dually cools,  and  the  steam  included  in  it 
condenses  into  water.  When  this  is  the 
case,  as  the  air  was  at  first  driven  out  by 
the  steam,  and  cannot  return  again,  all 
the  cocks  being  shut,  a  vacuum  is  form- 
ed in  the  receiver ;  consequently,  there  is 
nothing  to  counterbalance  the  pressure  of 
the  atmosphere,  which  acting  upon  the 
water  in  the  well,  forces  it  up  the  rising- 
pipe,  and  fills  the  receiver.  The  steam- 
cock  is  now  opened ;  and  the  steam  from 
the  boiler  rushing  in  with  great  violence, 
presses  upon  the  surface  of  the  water  in 
the  receiver,  and  forcing  it  through  the 
pipe  into  the  rising-pipe,  causes  it  to 
shut  the  valve  n,  and  open  the  other  valve 
f;  and,  provided  the  steam  be  sufficient- 
ly strong,  will  force  it  up  the  rising-pipe 
to  the  top  k,  where  it  is  delivered.  The 
cock  c  is  kept  open  until  all  the  water  be 
driven  out  of  the  receiver,  and  it  is  again 
filled  with  steam.  The  regulator  is  now 
applied,  which  shuts  the  steam-cock, 
whilst  at  the  same  time  it  opens  the  injec- 
tion-cock. The  rising-pipe  being  still  full 
of  water,  a  stream  of  cold  water  proceeds 
through  the  pipe  c,  and  enters  the  receiver 
in  a  shower.  This  instantly  condenses  the 
steam  in  the  receiver,  and  produces  a  va- 
cuum as  before ;  in  consequence  of  which, 
the  water  from  the  well  is  again  forced  up 
by  the  external  pressure  of  the  atmos- 
phere, and  the  receiver  is  again  filled  with 
water.  The  regulator  is  then  turned, 
which  shuts  the  injection-cock  and  opens 
the  steam-cock,  which  permits  the  steam 


from  the  boiler  to  press  upon  the  walei*., 
and  again  force  it  up  the  rising-pipe.  This 
operation  filling  the  receiver  with  water 
by  means  of  a  vacuum  produced  in  it,  and 
forcing  it  up  the  rising-pipe  by  the  pres- 
sure of  the  steam  from  the  boiler,  is  con- 
stantly repeated,  by  merely  turning  the 
regulator,  which  shuts  and  opens  the 
steam-cocks  and  injection-cocks  alter- 
nately. 

This  construction  of  the  steam  engine, 
is  extremely  simple,  and  might  perhaps 
be  successfully  applied  for  some  purposes. 
Hut  it  has  several  considerable  defects,  it 
may  readily  be  apprehended, that  the  ac 
tion  of  the  direct  steam  on  any  definite 
surface,  such,  for  example,  as  a  square 
inch,  will  be  accurately  equal  to  the  reac- 
tion of  the  water  which  is  forced  up  ;  and 
consequently,  that  Savary's  engine  wffi 
require  steam  more  elastic  than  the  air  of 
the  atmosphere,  in-  every  case  except 
where  the  water  is  raised  no  higher  than 
it  can  be  by  the  vacuum  that  is  produced, 
and  the  pressure  of  the  atmosphere. 

When  the  water  is  forced  up  through 
the  rising-pipe,  every  square  inch  of  the 
boiler  must  sustain  a  pressure  equal  to  a 
column  of  water  an  inch  square,  and  of 
the  height  of  the  pipe  above  the  boiler. 
This,  therefore,  requires  very  strong  ves 
sels,  and  several  accidents  have  happened 
by  their  bursting  when  the  safety  valve 
was  loaded  too  much- 

But  the  greatest  defect  of  this  machine 
is  the  great  waste  of  steam,  and  conse- 
quently of  fuel.  For  when  the  steam  is 
admitted  to  the  top  of  the  cold  water  in 
the  receiver,  it  is  condensed  with  great 
rapidity;  and  the  water  does  not  begin  to 
yield  to  its  pressure,  until  its  surface  be 
so  not,  as  not  to  condense  any  more  steam. 
It  now  descends,  but  as  by  that,  a  new 
part  of  the  side  of  the  receiver  is  exposed 
to  the  steam,  more  is  condensed,  so  that 
a  condensation  of  the  steam  is  going  on 
all  the  while  the  water  is  descending. 
This  too,  must  necessarily  be  repeated 
every  stroke,  as  the  receiver  is  cooled 
every  time  it  is  filled  with  water. 

Mr.  Savary  succeeded  in  raising  water 
to  small  heights,  and  erected  several  en- 
gines in  different  parts  of  England ;  but 
he  could  make  nothing  of  deep  mines. 
Many  attempts  have  been  made  to  correct 
these  defects,  but  hitherto  without  much 
success. 

In  the  beginning  of  the  eighteenth  cen- 
tury, Newco men,  an  ironmonger  or  smith, 
and  Cauly,  a  glazier  at  Dartmouth,  in  De- 
vonshire, in  England,  first  conceived  the 
project  of  applying  a  piston  with  a  lever, 
and  other  machinery.  They  were  content- 
ed to  share  the  profits  of  the  invention  with 


Savamxt?  Stjeam  XA'Cixas.    Flate  XV ill. 


J.JI.Stymcur  se. 


STE 


STE 


Savary,  who  procured  a  patent  for  it  in 
1705,  in  which  they  were  all  three 
joined. 

Fig".  2,  exhibits  a  section  of  Newco- 
men's  engine :  a  is  the  boiler,  built  in 
brick-work.  In  the  top  of  the  boiler  is  a 
steam-pipe,  c,  communicating1  with  the  cy- 
linder by  which  is  of  metal,  and  is  bored 
very  truly.  The  lower  aperture  of  this 
pipe  is  shut  by  the  plule  n>  which  is 
ground  very  flat,  so  as  to  apply  very  ac- 
curately to  the  whole  circumference  of 
the  orifice.  This  plate  is  called  the  re- 
gulator or  steam-cock,  and  it  turns  hori- 
zontally round  an  axis,  o,  which  passes 
through  the  top  of  the  boiler,  and  is  fitted 
by  grinding  to  the  socket,  so  as  to  be 
steam-tight.  It  is  opened  and  shut  by  a 
handle  fixed  to  its  axis. 

In  the  cylinder  b,  is  a  solid  piston  p, 
well  fitted  into  it,  and  made  air-tight  by  a 
packing  of  leather  or  soft  rope,  well  filled 
with  tallow,  and  for  greater  security,  a 
small  quantity  of  water  is  kept  above  the 
piston. 

_  The  piston-rod  d  is  suspended  by  a 
chain,  which  is  fixed  to  the  upper  extre- 
mity of  the  arched  head  e  of  the  great 
lever  or  working-beam,  e  f  g,  which  turns 
on  the  gudgeon  f.  There  is  a  smilar 
arched  head  g,  at  the  other  end  of  the 
beam,  to  the  upper  extremity  of  which 
is  fixed  a  chain,  carrying  the  pump- 
rod  h,  which  raises  the  water  from  the 
mine. 

The  load  on  this  end  of  the  beam  is 
made  to  exceed  considerably  the  weight 
of  the  piston  at  the  other  extremity. 

At  a  small  height  above  the  top  of  the 
cylinder,  is  a  cistern  called  the  injection, 
cistern,  i.  From  this  descends  the  injec- 
tion-pipe, k,  which  enters  the  bottom  of  the 
cylinder,  and  terminates  in  a  noz.zle 
pierced  with  holes.  This  pipe  has  a  cock, 
/,  called  the  injection-cock. 

At  the  opposite  side  of  the  cylinder,  a 
little  above  its  bottom,  there  is  a  lateral 
pipe,  m,  turning  upwards  at  the  extre- 
mity, and  there  covered  by  a  clack-valve, 
c  alled  the  snifting-valve,  which  has  a  little 
dish  round  it,  to  hold  water  for  keeping  it 
air-tight. 

There  proceeds  also  from  the  bottom 
of  the  cylinder,  a  pipe  g,  of  which  the 
lower  end  is  turned  upwards,  and  is  co 
vered  with  a  valve  r.  This  part  is  im 
mersed  in  a  cistern  of  water,  called  the 
hot-well,  and  the  pipe  itself  is  called  the 
eduction-pipe. 

Lastly,  the  boiler  is  furnished  with  a 
safety-valve,  called  the  puppet-clack,  in  the 
same  manner  as  in  Savary's  engine.  This 
valve  is  generally  loaded  with  one  or  two 
pounds  in  the  square  inch,  so  that  it  al- 
VOL.  IT. 


lows  the  steam  to  escape  when  its  elasti- 
city  is  one-tenth  greater  than  that  of  the 
atmosphere,  Thus  all  risk  of  bursting 
the  boiler  is  avoided,  the  pressure  out- 
wards being  very  moderate. 

When  the  cistern  for  the  injection  wa- 
ter i,  cannot  be  supplied  by  pipes  from 
some  more  elevated  source,  water  is 
raised  by  the  machine  itself.  A  small 
lifting-pump,  s,  is  worked  by  a  rod,  r,  sus- 
pended from  a  small  arch  upon  the  great 
beam  ;  this  forces  water  through  the  pipe 
t,  into  the  injection-cistern. 

The  parts  of  the  engine  being  now  de- 
scribed, the  operation  is  as  follows  : 

Suppose  the  piston  and  lever  in  the  po- 
sition represented  in  the  plate,  and  the 
water  in  the  boiler  in  a  state  of  ebullition, 
the  steam  and  injection-cocks  being  shut. 
Having  opened  the  steam-cock,  n,  the 
steam  from  the  boiler  will  immediately 
rush  in,  and  Hying  all  over  the  cylinder, 
will  mix  with  the  air. 

Much  of  it  will  be  condensed  by  the 
cold  surface  of  the  cylinder  and  piston, 
and  the  water  produced  from  it  will 
trickle  down  the  sides,  and  run  off  by  the 
eduction-pipe.  This  condensation,  nd 
waste  of  steam,  will  go  on  until  the  whole 
cylinder  and  piston  be  made  as  hot  as 
boiling  water. 

When  this  happens,  the  steam  will  be- 
gin to  issue  through  the  snifting  valve, 
slowly  at  first,  and  cloudy,  being  mixed 
with  much  air ;  but,  by  degrees,  it  will 
become  more  transparent,  having  carried 
off  the  greatest  part  of  the  air  which  fill- 
ed the  cylinder. 

When  the  attendant  perceives  that  the 
blast  at  the  snifting-valve  is  strong  and 
steady,  and  the  boiler  is  supplied  with 
steam  of  a  proper  strength,  appearing  by 
the  renewal  of  its  discharge  at  the  safety 
valve,  which  had  stopped  while  the  cylin- 
der was  filling,  he  shuts  the  steam-cock, 
n,  and  opens  the  injection-cock,  /.  The 
pressure  of  water  in  the  injection-pipe 
forces  some  out  into  the  cylinder,  which 
condenses  the  steam  and  forms  a  partial 
vacuum,  as  explained  above 

The  upper  side  of  the  piston  is  now  ex- 
posed to  the  whole  pressure  of  the  atmos- 
phere, which  not  being  counterbalanced 
on  the  under  side,  will  act  with  its  whole 
force  on  the  piston,  and,  provided  there 
be  not  too  much  weight  on  the  other  end, 
will  raise  it,  the  piston  going  to  the  bot- 
tom of  the  cylinder. 

When  the  piston  has  gone  down  as  low. 
as  necessary,  the  injection-cock  is  shut, 
and  the  steam-cock  opened.    TJie  steam, 
I  which  has  been  accumulating  above  the 
I  water  in  the  boiler,  during  the  time  of  the 
I  descent  of  the  piston,  and  is  now  issuing 


STE 


STE 


throtigh  the  puppet-clack,  as  soon  as  the 
steam-cock  is  opened,  rushes  violently 
into  the  cylinder,  having-  a  greater  elasti- 
city than  that  of  the  air.  ft  therefore  im- 
mediately  blows  open  the  snifting-valve, 
through  which  it  drives  out  the  air  that 
had  been  disengaged  from  the  injection- 
water. 

At  the  same  time,  the  water  which  had 
been  injected  before,  and  the  condensed 
steam,  run  out  through  the  eduction-pipe 
7,  and  lifting  up  the  valve  r,  How  into  the 
hot -well. 

By  the  admission  of  the  steam  under 
the  piston,  the  pressure  of  the  atmosphere 
on  the  top  is  counterbalanced,  and  the  pis- 
ton is  free  to  move  upwards  or  down- 
wards. . 

But  the  other  end  of  the  beam  being- 
broader,  so  as  to  be  heavier  than  the  pis- 
ton, now  raises  it  to  the  top  of  the  cylin- 
der, whence  it  is  again  forced  downwards 
by  the  pressure  of  the  atmosphere,  as 
soon  as  a  vacuum  is  formed  under  it  by 
the  admission  of  the  injection -water.  In 
this  manner  the  operation  is  repeated; 
the  piston  being  forced  down  by  the 
weight  of  the  atmosphere,  raises  the  other 
end  of  the  beam,  with  whatever  is  attach- 
ed to  it;  and,  on  the  other  hand,  when 
the  pressure  of  'the  atmosphere  is  coun- 
terbalanced by  the  steam  under  the  pis- 
ton, the  siiperior  weight  of  the  pump-end 
of  the  beam  brings  the  piston  up  again. 

We  now  see  the  difference  betw  een  Sa- 
vary's  and  Newcomen's  engine,  in  respect 
to  principle.  Savary's  was  an  engine  that 
raised  water  by  the  force  of  steam  ;  but 
Newcomen's  raises  water  entirely  by  the 
pressure  of  the  atmosphere,  and  the  steam 
is  employed  merely  as  the  most  expedi- 
tipus  mode  of  producing  a  vacuum,  into 
which  the  atmospherical  pressure  may 
impel  the  first  mover  of  his  machine. 

We  see  also  the  great  superiority  of 
this  new  machine.  We  have  no  need  of 
steam  of  great  and  dangerous  elasticity  ; 
and  w  e  operate  by  means  of  very  mode- 
rate heats,  and  consequently  with  much 
smaller  quantity  of  fuel ;  and  there  are  no 
bounds  to  the  power  of  this  machine. 
How  deep  soever  a  mine  may  be,  a  cylin- 
der may  be  employed  of  such  dimensions, 
that  the  pressure  of  the  air  may  exceed, 
in  any  degree,  the  weight  of  the  column 
of  water  to  be  raised.  And  lastly,  this 
form  of  the  machine  renders  it  applicable 
to  almost  every  mechanical  purpose;  be- 
cause a  skilful  mechanic  can  readily  find 
a  method  of  converting  the  reciprocating 
motion  of  the  working  beam  into  a  motion 
'of  any  kind  which  may  suit  his  purpose. 
Savary's  engine  could  hardly  admit  of 


such  a  general  application,  and  seems  al  - 
most  restricted  to  raising  water. 

Inventions  improve  by  degrees.  New- 
comen's engine  was  first  offered  to  the 
public  in  1705.  But  many  difficulties  oc- 
curred in  the  execution  of  it,  which  were 
removed  one  by  one ;  and  it  was  not  till 
1712,  that  the  engine  seemed  to  give  con- 
fidence in  its  efficacy. 

The  most  exact  and  unremitting  atten  - 
tion was  required,  to  open  and  shut  the 
cocks  precisely  at  the  proper  time;  for 
neglect  might  be  ruinous  to  the  machine, 
by  the  conhned  steam  beating  out  the  bot- 
tom of  the  cylinder,  or  allowing  the  pis- 
ton to  be  wholly  drawn  out  of  it.  Stops 
were  contrived  to  prevent  these  accidents; 
then  strings  were  used  to  connect  the 
handles  of  the  cocks  with  the  beam,  so 
that  they  should  be  turned  whenever  it 
was  in  certain  positions.  1  hese  were  gra~ 
dually  changed,  and  improved  into  de- 
tents, and  catches  of  different  shapes, 
at  last  Mr.  Beighton,  a  very  ingenious 
and  well  informed  artist,  simplified  the 
whole  of  these  subordinate  movements* 
and  otherwise  very  much  improved  this 
machine.  . 

The  greatest  improvement  that  lias 
since  been  made  on  Newcomen's  engine, 
has  been  in  the  manner  of  placing  the 
boiler.  Instead  of  placing  it  underneath 
the  cylinder,  it  is  built  at  some  distance 
from  it,  and  sometimes  in  a  separate 
building. 

About  1762,  Mr.  Watt  began  to  turn 
his  attention  to  this  machine,  which  he  has 
since  brought  to  so  great  a  degree  of  per- 
fection. 

But  before  we  explain  Mr.  Watt's  em 
gines,  it  is  necessary  to  premise  a  short 
account  of  the  imperfections  of  the  old 
steam  engines,  and  their  causes. 

The  steam  or  vapour  which  arises  from 
water  confined  in  a  close  vessel,  and  heat- 
ed a  few  degrees  above  the  point,  at  which 
it  boils  in  the  open  air,  becomes  an  elastic 
fluid,  uniform  and  transparent,  about  half 
the  gravity  of  atmospheric  air,  very  much 
greater  in  bulk,  than  the  water  of  which 
it  is  composed,  and  capable  of  being  again 
reduced  to  water  when  brought  into  con- 
tact with  matter  of  a  less  degree  of  heat 
than  itself. 

The  pressure  of  the  atmosphere,  or  any 
equivalent  resistance,  prevents  the  pro- 
duction of  steam,  until  the  water  be  heat- 
ed to  212  degrees  of  Fahrenheit's  ther- 
mometer ;  but  w  hen  that  pressure  is  re- 
moved, or  the  water  be  placed  in  a  ves- 
sel exhausted  of  air,  steam  is  produced 
from  it  when  it  is  colder  than  the  h.umaix 
blood. 


STE  STE 


On  the  contrary,  if  water  be  pressed 
upon  by  air  or  steam,  which  are  more 
compressed  than  the  atmosphere,  a  de- 
gree of  heat  above  212  degrees,  is  neces- 
sary for  the  production  of  steam  ;  and 
the  difference  of  heats  at  which  water 
boils  under  different  pressures,  increases 
in  a  less  proportion  than  the  pressure 
themselves  ;  so  that  a  double  pressure, 
requires  less  than  a  double  increase  of 
sensible  heat. 

The  experiments  which  have  been  pub- 
lished, concerning  the  bulk  of  water  when 
converted  into  steam,  are  erroneous  ;  and 
the  conclusions  drawn  from  them  make 
that  bulk  greater  than  it  really  is.  It  has 
been  known  for  some  time,  that  water 
would  boil  in  an  exhausted  receiver  at  a 
low  degree  of  heat. 

If  we  consider  the  common  steam  en- 
gine, we  shall  find  it  defective  ;  first,  be- 
cause the  vacuum  is  produced  by  throw- 
ing cold  water  into  the  cylinder,  to  con- 
dense  the  steam  :  that  water  becomes  hot, 
and  being  in  a  vessel  partially  exhausted, 
produces  a  steam,  which  in  part  resists 
the  pressure  of  the  atmosphere  upon  the 
piston,  and  lessens  the  power  of  the  en- 
gine. The  second  defect  is  the  destruc- 
tion of  steam,  which  unavoidably  happens 
upon  attempting  to  fill  a  cold  cylinder, 
with  that  fluid ;  for  the  injection-water, 
at  the  same  time  that  it  condenses  the 
steam,  not  only  cools  the  cylinder,  but 
remains  there,  until  it  be  extruded  at  the 
eduction-pipe,  by  the  steam  which  is  let 
in  to  fill  the  cylinder  for  the  next  stroke  ; 
and  that  steam  will  be  condensed  into 
water,  as  fast  as  it  enters,  until  all  the 
matter  which  comes  in  contact,  will  be 
nearly  as  hot  as  itself. 

Every  attempt  to  make  the  vacuum 
more  perfect,  by  the  addition  of  injection 
water,  will  cool  the  cylinder  more  effec- 
tually, and  cause  a  great  destruction  of 
steam  in  the  next  filling ;  and  if  the  en- 
gine has  already  a  proper  load,  the  de- 
struction of  steam  will  proceed  in  a  great- 
er ratio,  than  the  increase  of  power  by  the 
amendment  of  the  vacuum. 

Though  it  appears  that  the  construc- 
tors of  steam  engines,  have  never  investi- 
gated these  causes  ;  yet  they  have  been 
so  sensible  of  the  effects,  that  a  judicious 
engineer  does  not  attempt  to  load  his  en- 
gine, with  a  column  of  water  7  lbs.  for  each 
square  inch,  of  the  area  of  the  piston. 

Mr.  Watt's  improvements  are  founded 
upon  these,  and  some  other  collateral  ob- 
servations. He  preserves  an  uniform  heat 
in  the  cylinder  of  his  engines,  by  suffer- 
ing no  cold  water  to  touch  it,  and  by  pro- 
tecting it  from  the  air  or  other  cold  bo- 
dies, by  a  surrounding  case  filled  witli  the 


steam,  or  with  hot  air  or  water,  and  by 
coating  it  over  with  substances,  that  trans- 
mit heat  slowly.  lie  makes  his  vacuum 
to  approach  nearly  to  t  hat  of  the  barome- 
ter, by  condensing  the  steam  in  a  sepa- 
rate vessel,  called  the  condenser  ;  which 
may  be  cooled  at  pleasure,  without  cool- 
ing the  cylinder,  either  by  injection  of 
cold  water,  or  by  surrounding  the  con- 
denser with  it ;  and  generally  by  both. 
He  extracts  the  injection-water  and  de- 
tached air,  from  the  cylinder  or  conden- 
ser, by  pumps,  which  are  wrought  by 
the  engine  itself;  or  he  blows  it  out  by 
the  steam. 

As  the  inside  of  the  cylinder  was  in  the 
old  engine  exposed  to  the  air,  at  every 
stroke  when  the  piston  descended,  and 
was  considerably  cooled  thereby,  he  in- 
closes the  top  of  the  cylinder,  by  a  metal 
plate,  having  a  hole  in  it,  through  which 
the  piston-rod  works  in  a  collar  of  lea- 
thers ;  and  instead  of  employing  the  pres- 
sure of  the  atmosphere,  to  force  down  the 
piston,  he  introduced  the  steam  above  the 
piston,  when  the  vacuum  is  formed  un- 
derneath, and  employs  it  to  produce  this 
effect :  thus  making  the  direct  pressure 
of  the  steam,  the  moving  power,  as  in  the 
original  construction  of  the  engine. 

The  last  great  improvement  made  by 
Mr.  Watt,  was  his  giving  an  impulse  to 
the  piston  by  the  steam,  both  in  descend- 
ing and  ascending,  instead  of  being  im- 
pelled, as  in  the  old  engine,  during  the 
descent  of  the  piston  only. 

Having  thus  briefly  mentioned  the  prin- 
cipal improvements,  made  in  the  steam 
engine,  by  Mr.  Watt,  we  shall  proceed  to 
describe  one  of  his  engines,  on  the  latest 
construction. 

A  is  the  boiler,  to  which  Mr.  Watt  has 
paid  very  great  attention.  It  is  general- 
ly of  an  oblong  form  ;  and  the  flame,  after 
striking  on  its  concave  bottom,  circulates 
round  the  sides,  and  sometimes  returns 
in  a  pipe  through  the  body  of  the  water, 
before  it  is  suffered  to  go  up  into  the 
chimney.  In  his  engines  there  are  com- 
monly two  of  these  boilers,  so  that  one 
of  them  may  work,  while  the  other  is  re- 
pairing. B  (Plate  XIX.  Fig.  1.)  is  the 
steam  pipe,  which  conveys,  the  steam  to 
the  cylinder  C,  which  is  cased,  and  closed 
at  top  by  a  plate,  having  a  collar  of  lea- 
thers, through  which  the  piston-rod  D 
works,  a  and  c  are  the  steam-valves, 
through  which  the  steam  enters  into  the 
cylinder :  it  is  admitted  through  a,  when 
it  is  to  press  the  piston  downwards,  and 
through  c  when  it  presses  upwards,  b  and 
d  are  the  eduction-valves,  through  which 
the  steam  passes  from  the  cylinder  into 
the  condenser  e,  which  is  a  separate  ves- 


STE 


STE 


sei  placed  in  a  cistern  of  cold  water,  and 
which  has  a  jet  of  cold  water  continually 
playing-  up  in  the  inside  of  it.  /  is  the  air- 
pump,  which  extracts  the  air  and  water 
from  the  condenser.  It  is  worked  by  the 
great  beam  or  lever,and  the  water  brought 
by  it  from  the  condenser,  after  being- 
brought  into  the  hot-well  g,  is  pumped 
up  ag-ain  by  the  pump  A,  and  is  brought 
back  ag-ain  into  the  boiler  by  the  pipe  t.  k 
is  another  pump,  also  worked  by  the  en- 
gine itself,  which  supplies  the  cistern  in 
which  the  condenser  is  placed,  with  cold 
water. 

In  the  old  engines,  where  the  working- 
stroke  was  only  downwards,  the  piston- 
rod  was  attached  to  the  beam  by  chains, 
which  bent  round  an  arch  on  the  end  of 
the  beam,  in  order  to  make  the  piston-rod 
move  always  in  a  perpendicular  direction. 
This  may  be  seen  in  the  plate  of  Newco- 
men's  engine  But  in  Mr.  Watt's  engines, 
where  the  working-stroke  is  doubled, 
that  is,  both  upwards  and  downwards, 
chains  could  not  answer  this  purpose,  as, 
when  the  piston  was  forced  upwards,  they 
would  slacken,  and  would  not  communi- 
cate the  motion  to  the  beam.  It  was  ne- 
cessary, therefore,  that  the  piston-rod 
should  be  fastened  to  the  beam  by  inflexi- 
ble bars  ;  but  that  the  stroke  might  be 
perpendicular,  a  particular  contrivance 
was  invented  by  Mr.  Watt,  which  is  exhi- 
bited in  Plate  XIX.  and  which  answers  the 
intended  purpose  admirably  It  is  usually 
called  the  parallel-joint ;  and  its  nature 
and  construction  will  be  easily  understood 
from  the  figure.  In  order  to  make  the 
engine  itself  open  and  shut,  the  steam  and 
eduction -valves,  long-  levers  are  attached 
to  them,  which  are  moved  by  the  piston- 
rod  of  the  air-pump  EF.  This  part  of  the 
apparatus,  is  called  the  working-geer,  and 
is  so  contrived,  that  the  valves  may  be 
worked  either  by  hand,  or  by  the  perpen- 
dicular rod.  By  shutting  these  valves, 
the  engine  may  be  stopped  in  an  in- 
stant. 

In  order  to  communicate  a  rotatory  mo- 
tion to  any  machinery,  by  the  motion  of 
the  beam  of  the  steam  engine,  Mr.  Watt 
makes  use  of  a  very  large  fly-wheel  G  ; 
on  the  axis  of  which  is  a  small  concentric 
toothed  wheel,  H.  A  similar  toothed- 
wheel,  I,  is  fastened  by  straps,  to  a  rod 
Coming  from  the  end  of  the  beam,  so  that 
it  cannot  turn  round  on  its  axis,  but  must 
rise  and  fall,  with  the  motion  of  the  great 
beam 

A  bar  of  iron  connects  the  centres  of 
these  two  small-toothed  wheels,  so  that 
they  cannot  quit  each  other.  When,  there- 
fore, the  beam  raises  the  wheel  I,  it  must 
move  round  the  circumference  of  the 


wheel  H,  and  turn  it  together  with  the 
fly :  and  it  will  be  evident,  upon  consi- 
deration,  that  the  fly,  driven  in  this  man- 
ner, will  make  two  revolutions  for  every 
one  of  the  wheel  I.  This  mode  of  moving 
the  fly,  is  preferable  to  a  crank :  as  it  goes 
with  twice  the  velocity.  This  contrivance 
j  is  called  the  sun  and  planet  wheel,  from 
|  the  resemblance  of  the  motion  to  that  of 
,  those  luminaries. 

The  valves  of  this  steam  engine  are  all 
i  puppet-valves,  as  these  are  found  less 
liable  to  be  out  of  order. 

The  mode  of  operation  in  Mr.  Watt's 
engine,  is  as  follows  : 

Suppose  the  piston  at  the  top  of  the 
cylinder,  in  the  situation  represented  in 
the  plate,  and  the  lower  part  of  the  cylin- 
der filled  with  steam.  By  means  of  the 
handle  E,  open  the  steam-valve  a,  and  the 
eduction. valve  r/,  the  levers  of  which  are 
connected  together ;  there  being  now  a 
communication  between  the  cylinder  and 
the  condenser,  the  steam  instantly  rushes 
into  the  condenser,  leaving  the  cylinder 
empty,  whilst  at  the  same  time  the"  steam 
from  the  boiler,  entering  by  the  steam- 
valve,  a,  presses  upon  the  piston,  and 
forces  it  down.  As  soon  as  the  piston 
has  arrived  at  the  bottom,  the  steam-valve 
c,  and  the  eduction-valve  b,  are  opened, 
whilst  the  valves  a  and  d  are  shut ; 
the  steam  therefore  immediately  rushes 
through  the  eduction-vVlve  6,  into  the 
condenser,  whilst  the  piston  is  forced  up 
again  by  the  steam,  which  is  now  admit- 
ted by  the  steam-valve  c. 

Fig.  2,  which  is  a  section  of  the  steam- 
pipes,  taken  at  right  angles  to  that  in  Fig. 
1,  shews  this  more  distinctly  ;  *  is  the 
pipe  which  conveys  the  steam  from  the 
boiler  ;  a  and  c  are  the  steam-valves,  and 
b  and  d  the  eduction-valves.  By  attend- 
ing to  the  operation  in  both  the  sections, 
the  reader  will  easily  understand  it.  It 
appears  at  first  a  little  confused,  by  there 
seeming  to  be  only  one  steam  pipe  for 
communicating  between  the  cylinder  and 
the  condenser;  but  the  difficulty  is  clear- 
ed up,  by  representing  both  the  pipes,  as 
in  Fig.  2. 

Fig.  3,  is  a  longitudinal  section  of  the 
boiler,  representing  the  mode  of  supply- 
ing it  with  water,  and  the  safety-valve  and 
cocks,  /is  a  small  cistern,  which  is  sup- 
plied with  water  from  the  hot-well,  as  re- 
presented in  Fig.  1 ;  from  the  bottom  of 
this  cistern,  a  pipe  goes  down  almost  to 
the  bottom  of  the  boiler,  where  it  turns 
up  a  little,  to  prevent  the  entrance  of  the 
steam  which  rises  from  the  bottom.  From 
the  side  of  this  cistern,  is  supported  a 
small  lever,  to  one  end  of  which  is  fasten- 
ed a  wire,  that  carries  a  stone  which 


STE 


STE 


hangs  in  the  water  of  the  boiler;  the 
other  end  of  the  lever  supporting  also  by 
a  wire,  a  valve  that  shuts  the  top  of  the 
pipe  that  goes  down  from  the  cistern. 
N'ow,  supposing  the  stone  just  at  the  sur- 
face of  the  water,  and  balanced  by  a 
weight  at  the  opposite  end  of  the  lever ;  it 
is  evident,  that  by  the  laws  of  hydrosta- 
tics, already  explained,  a  certain  part  of 
the  weight  of  the  stone  will  be  supported 
by  the  water,  so  long  as  it  continues  im- 
mersed in  it ;  but  if  a  part  of  the  water 
evaporate  by  boiling,  a  proportional  part 
of  the  stone  will  be  above  the  water,  con- 
sequently the  stone  will  bear  more  upon 
the  lever,  and  raise  the  weight  at  the 
other  end  ;  but  in  raising  that  weight,  it 
also  opens  the  valve  in  the  small  cistern, 
and  admits  water  until  it  stand  at  the 
same  height  in  the  boiler  as  before,  and 
then  the  valve  and  the  stone  being  again 
in  equilibrio,  the  valve  remains  shut  until 
a  new  quantity  is  evaporated.  By  this 
means  the  supply  of  water  is  very  gra- 
dual, and  not  by  fits  and  starts,  as 
here  described  for  the  sake  of  illustra- 
tion. 

It  is  found  by  experience,  to  be  a  much 
better  method  than  a  ball-cock,  and  the 
regular  supply  of  the  boiler  with  wa- 
ter, is  of  the  first  importance.  As  a  check 
upon  this,  and  to  know  perfectly  the 
height  of  the  water  in  the  boiler,  there  are 
two  cocks,  g  and  ht  one  of  which  reaches 
nearly  to  the  surface  of  the  water  when 
at  its  proper  height,  and  the  other  enters 
a  little  below  the  surface. 

It  is  evident,  that  if  the  water  be  at  the 
just  height,  and  you  open  gt  that  steam 
will  issue ;  and  if  h  be  opened,  water  will 
be  driven  out  by  the  pressure  of  the 
steam.  But  if  water  come  out  from  g, 
then  the  water  must  be  too  high  in  the 
boiler ;  and  if  steam  issue  from  ht  then 
the  water  is  too  low.  By  this  means,  it  is 
easy  to  know  at  all  times  the  exact  height 
of  the  water  in  the  boiler. 

i  is  a  safety-valve,  to  prevent  the  burst- 
ing of  the  boiler  by  the  steam  growing  too 
strong ;  k  is  the  pipe  which  conveys  the 
steam  to  the  engine. 

Fig.  4,  is  Mr.  Cartwright's  steam-en- 
gine, the  construction  of  which  evinces 
much  ingenuity,  a  is  the  cylinder,  which 
is  supplied  with  steam  from  the  boiler 
through  the  pipe  b ;  c  is  the  piston  in  the 
act  of  going  up ;  d  is  the  pipe  that  con- 
ducts the  steam  into  the  condenser  e, 
which  consists  of  two  cylinde  rs,  one  with* 
in  the  other,  leaving  a  small  space  be- 
tween them,  into  which  the  steam  is  ad- 
mitted ;  while  the  inner  cylinder  is  filled 
with  cold  water,  and  also  the  external 
cylinder  surrounded  by  the  same  ;  so  that, 


by  this  means,  a  very  large  surface  of 
steam  is  exposed,  though  no  water  is  suf- 
fered to  come  into  actual  contact  with  it. 

To  the  bottom  of  the  piston, c,  is  attach- 
ed a  rod,  with  another  piston,  e,  working 
in  the  pipe  d.  When  the  piston  e  arrives 
at  the  bottom  of  the  cylinder,  a  valve 
which  is  in  the  piston,  is  opened  by  its 
pressing  against  tlie  bottom,  and  opens  a 
communication  with  the  condenser,  whilst 
the  spring  k,  fixed  to  the  rod  of  the  pis- 
ton, shuts  the  valve  which  admits  the 
steam  from  the  boiler.  The  steam,  there- 
tore,  being  thus  condensed,  runs  into  the 
lower  pipe  f.  The  piston  e  arriving  at 
the  bottom  of  the  pipe  in  which  it  works 
at  the  same  time  with  c,  presses  upon  the 
condensed  water,  shuts  the  valve  J",  and 
forces  the  water  up  the  pipe  g,  into  the 
box  h.  The  air  which  is  disengaged  from 
the  water,  rises  to  the  top  of  the  box,  and, 
by  its  elasticity,  forces  the  water  through 
the  pipe  which  carries  it  back  again  in- 
to the  boiler.  When  the  air  accumulates 
in  the  box  to  such  a  degree  as  to  depress 
the  water,  the  ball-cock  falls  with  it,  and 
opens  a  valve  in  the  top  of  the  box,  which 
suffers  some  of  the  air  to  escape. 

When  all  the  steam  is  condensed,  tlie 
motion  of  the  fly  attached  to  the  machine 
brings  the  piston  up  again,  its  valve  now 
remaining  shut  by  its  weight.  *  On  arriving 
at  the  top,  it  presses  up  the  steam-valve, 
which  admits  the  steam  from  the  boiler  to 
force  it  down  as  before. 

/  and  m  are  two  cranks,  upon  whose  ax- 
is are  two  equal  wheels  working  in  each 
other,  for  the  purpose  of  converting  the 
perpendicular  motion  of  the  piston-rod  in- 
to a  rotatory  motion,  for  working  the  ma- 
chinery attached  to  it. 

But  the  most  valuable  part  of  this  en- 
gine is  in  the  construction  of  the  piston, 
which  Mr.  Cartwright  made  wholly  of 
metal,  and  so  as,  by  means  of  springs,  to 
fit  the  cylinder  very  exactly.  This  not  on- 
ly saves  the  expense  and  trouble  of  pack- 
ing, which  they  are  obliged  frequently  to 
renew  in  all  other  engines,  but  also  saves 
a  great  deal  of  steam,  on  account  of  the 
more  accurate  fitting  of  the  piston. 

As  it  is  evident,  from  its  construction, 
that  the  whole  of  the  steam  is  brought 
back  again  into  the  boiler,  it  affords  the 
means  of  employing  ardent  spirit  instead 
of  water,  and  thus  saving  a  great  deal  of 
fuel. 

Dr.  Smith  says,  that  in  the  first  fire  en- 
gine, a  boy  was  constantly  employed  to 
open  and  shut  alternately  the  communica- 
tion between  the  boiler  and  cylinder,  ac- 
cordingly as  the  piston  either  ascended  or 
descended.  One  of  these  boys  who  loved 
to  play  with  his  companions,  observed, 


STE 


STE 


I  hut  by  lying  a  string,  from  the  handle  of 
the  valve  which  opened  this  communica- 
tion, to  another  part  of  the  machine,  the 
vahe  would  open  and  shut  without  his 
assistance,  and  leave  him  at  liberty  to  di- 
vert himself  with  his  playfellows.  One  of 
the  greatest  improvements  that  have  been 
made  upon  this  machine  since  it  was  first 
invented,  was  in  this  manner  the  discove- 
ry of  a  boy  who  wanted  to  save  his  own 
labour. 

About  ten  months  ago,  Mr.  Arthur 
Woolf  announced  to  the  public  a  discove- 
ry respecting  the  expansibility  of  steam, 
which  promises  to  be  of  very  essential 
utility.  Mr.  Watt  had  formerly  ascertain- 
ed, that  steam  which  acts  with  the  expan- 
sive force  of  4  pounds  per  square  inch, 
against  a  safety-valve  exposed  to  the 
weight  of  the  atmosphere,  after  expand- 
ing itself  to  four  times  the  volume  it  thus 
occupies,  is  still  equal  to  the  pressure  of 


the  atmosphere.  But  Mr.  Woolf  has  gone 
much  farther,  and  has  proved,  that  quan- 
tities of  steam,  having  the  force  of  5,  6, 
7,  8,  9,  10,  See.  pounds  on  every  square 
inch,  may  be  allowed  to  expand  5,  6,  7, 8, 
9,  10,  &.c.  times  its  volume,  and  will  still 
be  equal  to  the  atmosphere's  weight,  pro- 
vided that  the  cylinder  in  which  the  ex- 
pansion takes  place,  has  the  same  tempe* 
rature  as  the  steam  before  it  began  to  ex- 
pand It  is  evident,  however,  that  an  in- 
crease of  temperature  is  necessary  both 
to  produce  and  to  maintain  this  augmen- 
tation of  the  steam's  expansive  force  above 
the  pressure  of  the  atmosphere.  At  the 
temperature  of  212°  of  Fahrenheit,  the 
force  of  steam  is  equal  only  to  the  pres- 
sure of  the  atmosphere,  and,  in  order  to 
give  it  an  additional  elastic  force  of  5 
pounds  per  square  inch,  the  temperature 
must  be  increased  to  about  227{,°,  as  is 
evident  from  the  following  table. 


Table  nf  the  pressures,  temperatures,  and  expansibility,  of  steam,  equal  to  the  force  of 

the  atmosphere. 


Elastic  force   of  steam 

Degrees  of  temperature 

No.  of  times  its  vol.  that 

predominating    over  the 

requisite  for  bringing  the 

steam  of  the  preceding  force 

pressure  of  the  atmosphere, 

steam  to  the  different  ex- 

and temperat  re  will  ex- 

and acting  upon  a  safety- 

pansive  forces  in  the  pre- 

pand,   and   still  continue 

valve. 

ceding  column. 

equal  to  the  pressure  of  the 

atmosphere. 

Pounds  per  square  inch. 

Degrees  of  heat. 

Expansibilitv. 

5 

227 A 

5 

6 

230| 

6 

7 

232^ 

7 

8 

235| 

8 

9 

237^ 

9 

10 

239^ 

10 

15 

250  h 

15 

20 

259i 

20 

25 

267 

25 

30 

273 

30 

35 

278 

35 

40 

282 

40 

In  this  manner,  by  small  additions  of 
temperature,  an  expansive  power  may  be 
given  to  steam,  which  will  enable  it  to  ex- 
pand 50,  100,  200,  300,  &c.  times  its  vo- 
lume, and  still  have  the  same  force  as 
the  atmosphere. 

Upon  this  principle  Mr.  Woolf  has  ta- 
ken out  a  patent  for  various  improvements 
on  the  steam  engine,  a  short  account  of 
which  we  shall  subjoin  in  the  words  of 
the  specification. 

If  the  engine  be  constructed  originally 


with  the  intention  of  adopting  the  preced- 
ing improvement,  it  ought  to  have  two 
steam  vessels  of  different  dimensions,  ac- 
cording to  the  expansive  force  to  be  com- 
municated to  the  beam,  for  the  smaller 
steam  cylinder  must  be  a  measure  for  the 
larger.  For  example,  if  steam  of  40 
pounds  the  square  inch  be  fixed  on,  then 
the  smaller  steam  vessel  should  be  at  least 
l-46th  part  the  contents  of  the  larger  one. 
Each  steam  vessel  should  be  furnished 
with  a  piston,  and  the  smaller  cylinder 


STE 


STE 


should  have  a  communication  both  at  its 
top  und  bottom,  with  the  boiler  which 
supplies  the  steam ;  which  communica- 
tions, by  means  of  cocks  or  valves,  are  to 
be  alternately  opened  and  shut  during  the 
working-  of  the  engine.  The  top  of  the 
smaller  cylinder  should  have  a  communi- 
cation with  the  bottom  of  the  larger  cy- 
linder, and  the  bottom  of  the  smaller  one 
with  the  top  of  the  larger,  with  proper 
means  to  open  and  shut  these  alternately 
by  cocks,  valves,  or  any  other  contri- 
vance. And  both  the  top  and  bottom  of 
the  larger  cylinder  should,  while  the  en- 
gine is  at  work,  communicate  alternately 
with  a  condensing  vessel,  into  which  a  jet 
of  water  is  admitted  to  hasten  the  conden- 
sation. Things  being  thus  arranged  when 
the  engine  is  at  woi  k,  steam  of  high  tem- 
perature is  admitted  from  the  boiler  to  act 
by  its  elastic  force  on  one  side  of  the 
smaller  piston,  while  the  steam  which  had 
last  moved  it  has  a  communication  with 
the  larger  cylinder,  where  it  follows  the 
larger  piston  now  moving  towards  the  end 
of  its  cylinder  which  is  open  to  the  con- 
densing vessel.  Let  both  pistons  end  their 
stroke  at  one  time,  and  let  us  now  sup- 
pose them  both  at  the  top  of  their  respec- 
tive cylinders  ready  to  descend  ;  then  the 
steam  of  40  pounds  the  square  inch,  en- 
tering above  the  smaller  piston,  will  car- 
ry it  downwards,  while  the  steam  below 
it,  instead  of  being  allowed  to  escape  into 
the  atmosphere,  or  applied  to  any  other 
purpose,  will  pass  into  the  larger  cylinder 
above  its  piston,  which  will  take  its  down- 
ward stroke  at  t  he  same  time  that  the  pis- 
ton of  the  smaller  cylinder  is  doing  the 
same  thing ;  and,  while  this  goes  on,  the 
steam  which  last  filled  the  larger  cylin- 1 
der,  in  the  upward  stroke  of  the  engine, 
will  be  passing  into  the  condenser,  to  be 
condensed  in  the  downward  stroke.  When 
the  pistons  in  the  smaller  and  larger  cy- 
linder have  thus  been  made  to  descend  to 
the  bottom  of  their  cylinders,  then  the 
steam  from  the  boiler  is  to  be  shut  off 
from  the  top,  and  admitted  to  the  bottom 
of  the  smaller  cylinder,  and  the  commu- 
nication between  the  bottom  ol  the  small- 
er, and  the  top  of  the  larger  cylinder  is 
also  to  be  cut  off,  and  the  communication 
to  be  opened  between  top  of  the  smaller 
and  the  bottom  of  the  larger  cylinder ; 
the  steam  which,  in  the  downward  stroke 
of  the  engine,  filled  the  larger  cylinder 
being  now  open  to  the  condenser,  and  the 
communication  between  the  bottom  of  the 
larger  cylinder  and  the  condenser  cut  off; 
and  so  on  alternately,  admitting  the  steam 
to  the  different  sides  of  the  smaller  piston, 
while  the.  steam  last  admitted  into  the 
smaller  cylinder  passes  alternately  to  the 


different  sides  of  the  larger  piston  in  the 
larger  cylinder,  the  top  and  bottom  of 
which  are  made  to  communicate  alter- 
nately with  the  condenser. 

In  an  engine  where  these  improvements 
are  adopted,  that  waste  of  steam  which 
arises  in  other  engines  from  steam  pass- 
ing the  piston,  is  totally  prevented,  for 
the  steam  which  passes  the  piston  in  the 
smaller  cylinder  is  received  into  the 
larger.' 

Mr.  Woolf  has  also  shown  how  the  pre- 
ceding arrangement  may  be  altered,  and 
has  pointed  out  various  other  modifica- 
tions of  his  invention,  and  the  method  of 
applying  his  improvements  to  steam  en- 
gines which  are  already  constructed. 

On  the  Power  of  Steam  Engines,  and  the 
.Method  of  computing  it. 
From  the  account  which  has  been  given 
of  the  steam  engine,  and  the  mode  of  its 
operation,  it  must  be  evident  that  its 
power  depends  upon  the  breadth  and 
height  of  the  cylinder,  or  in  other  words, 
on  the  area  of  the  piston  and  the  length 
of  its  stroke.  If  we  suppose  that  no  force 
is  lost  in  overcoming  the  inertia  of  the 
great  beam,  and  that  the  lever  by  which 
the  power  acts  is  equal  to  the  lever  of  re- 
sistance ;  then,  if  steam  of  a  certain  elas- 
tic force  be  admitted  above  the  piston,  so 
as  to  press  it  downwards  with  a  force  of 
a  little  more  than  100  pounds,  it  will  be 
able  to  raise  a  weight  of  100  pounds  hang- 
ing at  the  end  of  the  great  beam.  When 
the  piston  has  descended  to  the  bottom 
of  the  cylinder,  through  the  space  of  four 
feet,  the  weight  will  have  risen  through 
the  same  space,  and  10Q  pounds  raised 
through  the  height  of  four  feet,  during 
one  descent  of  the  piston,  will  express  the 
mechanical  power  of  the  engine.  But  if 
the  area  of  the  piston,  and  the  length  of 
the  cylinder  be  doubled,  while  the  expan- 
sive force  of  the  steam,  and  the  time  of 
the  piston's  descent  remain  the  same,  the 
mechanical  energy  of  the  engine  will  be 
quadruple,  and  will  be  represented  by  200 
pounds  raised  through  the  space  of  eight 
feet  during  the  time  of  the  piston's  de- 
scent. The  power  of  steam  engines  there- 
fore is,  ceteris  paribus,  in  the  compound 
ratio  of  the  area  of  the  piston,  and  the 
length  of  the  stroke.  These  observations 
being  premised,  it  will  be  easy  to  com- 
pute the  power  of  steam  engines  of  any 
size. 

Thus,  let  it  be  required  to  determine 
the  power  of  a  steam  engine  whose  cylin- 
der is  24  inches  diameter,  and  which 
makes  22  double  strokes  in  a  minute, 
each  stroke  being  5  feet  long,  and  the 
force  of  the  steam  being  equal  to  a  pres- 


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sure  of  12  pounds  avoirdupois  upon  every 
square  inch.  [The  working  power  is  ge- 
nerally reckoned  at  10  lbs.  on  every  cir- 
cular inch,  and  Smeaton  makes  it"  only 
7  lbs.  The  effective  pressure  which  we 
have  adopted  is  between  these  extremes, 
being  equivalent  to  9.42  lbs.  on  every  cir- 
cular inch.]  The  diameter  of  the  piston 
being  multiplied  by  its  circumference,  and 
divided  by  4,  will  give  its  area  in  square 

.    .        .  24X3.1416X24 

inches  ;  thus,   -  =  452.4, 

4 

the  number  of  square  inches  exposed  to 
the  pressure  of  the  steam.  Now  if  we 
multiply  this  area  by  12  pounds,  the  pres- 
sure upon  every  square  inch,  we  will  have 
452.4  X  12  =  5428.8  pounds  the  whole 
pressure  upon  the  piston,  or  the  weight 
which  the  engine  is  capable  of  raising. 
But  since  the  engine  performs  22  double 
strokes,  5  feet  long  in  a  minute,  the  pis- 
ton must  move  through  22  X  5  X  2  =  220 
feet  in  the  same  time  ;  and  the  e fore  the 
power  of  the  engine  will  be  represented 
by  5428.8  pounds  avoirdupois,  raised 
through  220  feet  in  a  minute,  or  10.4 
hogsheads  of  water,  ale  measure,  raised 
through  the  same  height  in  the  same  time. 
Now  this  is  equivalent  to  5428  8  X  220  = 
1194336  pounds,  or  10.4X220=  2288 
hoghsheads  raised  through  the  height  of 
1  foot  in  a  minute.  This  is  the  most  un- 
equivocal expression  of  the  mechanical 
power  of  any  machine  whatever,  that  can 
possibly  be  obtained.  But  as  steam  en- 
gines were  substituted  in  the  room  of 
horses,  it  has  been  customary  to  calculate 
their  mechanical  energy  in  horse-po°xers, 
or  to  find  the  number  of  horses  which 
could  perform  the  same  work.  This  in- 
deed is  a  very  vague  expression  of  power, 
on  account  of  the  different  degrees  of 
strength  which  different  horses  possess. 
But  still,  when  we  are  told  that  a  steam 
engine  is  equal  to  16  horses,  we  have  a 
more  distinct  conception  of  its  power, 
than  when  we  are  informed  that  it  is  ca- 
pable of  raising  a  number  of  pounds 
through  a  certain  space  in  a  certain  time,  j 
Messrs.  Watt  and  Boulton  suppose  k 
horse  capable  of  raising  32,000  pounds  j 
avoirdupoise,  one  foot  high  in  a  minute,  i 
while  Dr.  Desaguliers  makes  it  27,500  ; 
pounds,  and  Mr.  Smeaton  only  22,916.  j 
If  we  divide,  therefore,  the  number  of  i 
pounds  which  any  steam  engine  can 
raise  one  foot  high  in  a  minute,  by  these 
three  numbers,  each  quotient  will  repre- 
sent the  number  of  horses  to  which  the  ; 
engine  is  equivalent.  Thus,  in  the  pre-  j 
sent  example  l\92x0H<i  =  37  1_3  horses  j 
according  to  Watt  and  Boulton;  rjjjffip  j 
—  43  1-3  horses,  according  to  Desagu- 1 


liers ;  and  =  52  1-7  horses,  ac- 

cordind  to  Smeaton.  In  this  calculation 
it  is  supposed  that  the  engine  works  only 
eight  hours  a-day ;  so  that  if  wrought  du- 
ring the  whole  24  hours,  it  would  be  equi- 
valent to  thrice  the  number  of  horses 
found  by  the  preceding  rule.  We  cannot 
help  observing,  and  it  is  with  sincere  plea- 
sure that  we  pay  that  tribute  of  respect  to 
the  honour  and  integrity  of  Messrs.  Watt 
and  Boulton,  which  has  every  where  been 
paid  to  their  talents  and  genius, — that  in 
estimating  the  power  of  a  horse,  they 
have  assigned  a  value  the  most  unfavour- 
able to  their  own  interests.  While  Mr. 
Smeaton  and  Dr.  Desaguliers  would  have 
made  the  engine  in  the  preceding  exam- 
ple equivalent  to  52  or  53  horses;  the  pa- 
tentees themselves  state  that  it  will  per- 
form the  work  only  of  37.  How  unlike  is 
this  conduct  to  some  of  our  modern  in- 
ventors, who  ascribe  powers  to  their  ma- 
chines which  cannot  possibly  belong  to 
them,  and  employ  the  meanest  arts  for 
ensnaring  the  public. 

We  shall  now  state  the  performance  of 
some  of  these  engines,  as  determined  by 
experiment.  An  engine  whose  cylinder 
is  31  inches  in  diameter,  and  which  makes 
17  double  strokes  per  minute,  is  equiva- 
lent to  40  horses,  working  day  and  night, 
and  burns  11,000  pounds  of  Staffordshire 
coal  per  day.  When  the  cylinder  is  19 
inches,  and  the  engine  makes  25  strokes 
of  4  feet  each  per  minute,  its  power  is 
equal  to  that  of  12  horses  working  con- 
stantly, and  burns  3,700  pounds  of  coals 
per  day.  And  a  cylinder  of  24  inches, 
which  makes  22  strokes  of  5  feet  each, 
performs  the  work  of  20  horses,  working 
constantly,  and  burns  5,500  pounds  of 
coals.  Mr.  Boulton  has  estimated  their 
performance  in  a  different  manner.  He 
states  that  one  bashel  of  Newcastle  coals, 
containing  84  pounds,  will  raise  30  mil- 
lion pounds  one  foot  high ;  that  it  will 
grind  and  dress  11  bushels  of  wheat;  that 
it  will  slit  and  draw  into  nails  5  cwt.  of 
iron  ;  that  it  will  drive  1,000  cotton  spin- 
dles, with  all  the  preparation-machinery, 
with  the  proper  velocity  ;  and  that  these 
effects  are  equivalent  to  the  work  of  ten 
horses. 

Mr.  Boulton  has  lately  constructed  an 
apparatus  tor  coining,  which  moves  by  an 
improved  steam  engine.  The  machinen. 
is  so  ingeniously  constructed,  that  four 
boys  of  ten  or  twelve  years  of  age  are  ca- 
pable of  striking  30,000  guineas  in  an 
hour  and  the  machine  itself  keeps  an  ac- 
curate account  of  the  number  which  is 
struck. 

It  is  due  to  the  merits  of  our  country. 


STE 


STE 


men  to  say,  that  considerable  improve- 
ments on  the  steam  engine  have  been 
made  in  this  country.  Among  the  num- 
ber, we  mention  with  pleasure,  the  im- 
provements of  Oliver  Evans,  esq.,  some  of 
which  we  present  the  reader  in  this  place. 
The  following  explanation  of  the  Colum- 
bian Engine  we  were  politely  furnished 
with  by  the  patentee.  For  further  infor- 
mation on  iteam  engines,  we  refer  the 
reader  to  Evans's  Treatise  on  Steam  En- 
gines, a  work  which  abounds  with  much 
practical  and  theoretical  knowledge. 

The  Columbian  Steavi  Engine. 
Plate  XX. 

A,  the  boiler. 

B,  the  working  cylinder. 

C,  the  lever  beam. 

D,  the  fly-wheel. 
*    E,  the  condenser. 

F,  the  water-pump. 

G,  the  supply  pump. 

H,  the  furnace. 

I,  the  chimney  flue. 

K,  the  safety-valve,  which  may  be  load- 
ed with  100  or  150  lbs.  to  the  inch  area  ; 
it  will  never  need  more,  and  it  must  never 
be  fastened  down. 

Operation. 

The  boiler  being  filled  with  pure  water 
as  high  as  the  dotted  line,  and  the  fire 
applied,  the  smoke  enters  the  centre  flue, 
Which  passes  through  the  centre  of  the 
water  to  ascend  the  flue  I,  and  thus  acts 
on  a  large  surface. 

When  the  steam  lifts  the  safety-valve, 
it  is  then  let  into  the  cylinder  by  opening 
the  throttle-valves,  to  drive  the  piston  up 
and  down,  which,  by  rod  1,  gives  motion 
to  the  fly-wheel,  and  wheel  2  gives  mo- 
tion to  a  shaft,  passing  through  the  posts, 
to  turn  the  spindle  of  the  rotatory  valves, 
3,  8,  which  lets  the  steam  both  oil"  and  on 
the  cylinder  at  the  proper  time. 

The  steam  escaping  by  pipe  4,  curved 
and  immersed  in  the  water  in  box  E,  which 
is  supplied  by  pump  F,  it  is  condensed, 
and  the  water  formed,  descends  by  pipe 
5  into  supply-pump  G,  and  is  forced  into 
the  boiler  again  by  pipe  6. 
-  The  snifting-valve  7,  is  necessary. — 
This  valve  lifts  at  every  puff  of  steam,  and 
a  small  quantity  of  air  escapes ;  and  it 
shuts,  and  a  vacuum  is  instantly  formed, 
as  the  crank  passes  the  dead  points. 

The  small  waste  of  water  may  be  sup- 
plied by  condensing  part  of  the  steam 
rising  from  the  condensing  water,  to  run 
down  the  pipe  9,  through  a  hole  in  the 
key  of  a  stop-cock,  one-thirty-second  part 
of  an  inch  diameter,— a  small  hole  indeed 
VOL.  II. 


to  supply  a  boiler  of  twenty  horses  power. 

No  sediment  can  accumulate  in  the 
boiler,  it  being  supplied  by  distilled  wa- 
ter. Therefore  it  will  last  much  longer, 
and  require  less  fuel  than  others.  Muddy, 
limestone,  or  salt  water,  or  the  juice  of 
the  sugar  cane,  &c.  Sec,  may  be  used  to 
condense ;  and  as  the  engine  works  equal- 
ly well  while  we  boil  away  the  condensing 
water,  we  may  boil  for  salt,  sugar,  &c ,  in 
working  the  engine,— thus  using  the  fuel 
for  double  purposes. 

If  the  steam  be  confined  by  the  load  on 
the  safety-valve,  to  raise  its  power  to  100 
pounds  to  the  inch  area  of  the  piston,  and 
the  cylinder  be  nine  inches  in  diameter, 
:.nd  the  stroke  of  the  piston  three  feet,  the- 
power  will  equal  twenty  horses  hitched; 
and  will  grind  20  bushels  of  grain  pet- 
hour,  or  saw  5000  feet  of  boards  in  twelve 
hours.  If  the  steam  be  confined  by  150 
pounds,  the  power  of  the  engine  will  be 
equal  to  thirty  horses,  when  the  steam  is 
shut  off  at  one-third  of  the  stroke,  and 
striking  thirty-six  strokes  per  minute.— 
Double  strokes  double  the  power 

The  more  the  steam  is  confined,  and 
the  shorter  it  be  shut  off  by  the  regulator, 
8,  the  greater  will  be  the  power  obtained 
by  the  fuel.  For  every  addition  of  30  de- 
grees heat  to.  the  water  doubles  the 
power.  So  that  doubling  the  heat  of  Che 
water,  increases  the  power  about  100 
times.  On  these  principles  fuel  may  be 
lessened  to  one  third  part  consumed  by 
other  engines.  This  engine  is  not  more 
than  one-fourth  the  weight  of  others ;  is 
more  simple,  durable,  and  cheap,  and 
more  suitable  for  every  purpose ;  espe- 
cially for  propelling-  boats  and  land  car- 
riages. It  requires  no  more  water  than 
the  fuel  will  evaporate  in  steam,  and  this 
steam  may  be  employed  to  warm  the 
apartments  of  factories  ;  or  the  condenser 
E  could  be  used  as  a  still  to  distil  spirits, 
or  a  vat  for  paper  making,  boiler  in  a 
brewery,  dye  factory,  &c.  &c. 

In  the  Philadelphia  steam  engines  (says 
Mr.  Fessenden,)  certain  innovations  have 
been. introduced,  which  we  hope  may  be 
found  to  be  improvements.  What  are 
styled  the  improvements,  consist,  princi- 
pally, in  making  use  of  a  wooden  chest  to 
contain  the  water,  through  which  the  flues 
of  the  furnace  wind  several  times  before 
their  discharge  into  the  chimney. 

These  wooden  boilers  are  supposed  to 
be  serviceable  in  consequence  of  their 
being  slow  conductors  of  heat,  and  the 
long  cylindrical'  heaters  exposing  a  very 
great  surface  of  iron  to  the  action  of  the 
water.  The  steam  engine  in  Centre 
Square  is  a  double  steam  engine,  with  a 
3  G 


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STI 


cylinder  of  thirty-two  inches.  Its  power 
is  calculated  for  not  merely  the  present, 
but  the  future  wants  of  this  city.  It  makes 
twelve  strokes  of  six  feet  per  minute,  for 
sixteen  hours  in  twenty-four,  in  which 
time  it  consumes  from  twenty -five  to  thir- 
ty-three bushels  of  Virginia  coals  of  the 
best  sort. 

Some  inconveniences  are  said  to  attend 
these  wooden  boilers,  such  as  steam  leak- 
ing the  joints  and  at  the  bolts.  A  conical 
wooden  boiler  has  been  adopted  as  it  ap- 
pears at  the  suggestion  of  Mr.  Oliver 
Evans,  with  hoops,  which  promises  every 
wished  for  success.  It  was  found  that  a 
combination  of  oak  and  pine  in  the  same 
boiler  was  liable  to  premature  decay  in 
consequence  of  the  pine  being  acted  upon 
by  the  acid  of  the  oak. 

At  the  lower  engine,  next  the  Schuyl- 
kill, which  is  a  double  steam  engine  of 
forty  inches  cylinder,  and  six  feet  stroke, 
a  cast  iron  boiler  has  been  put  up,  with 
straight  sides  and  semicircular  ends  ;  se- 
venteen feet  long  and  eight  feet  wide  at 
the  bottom ;  nineteen  feet  long  and  ten 
feet  wide  at  the;  height  of  five  feet  seven 
inches-  At  this  height  it  is  covered  by  a 
vault,  which  in  its  transverse  section  is 
semicircular,  and  in  its  longitudinal  sec- 
tion exhibits  half  its  plan.  The  bottom  is 
concave  every  way,  rising  one  foot  in  the 
centre.  The  fire  place  is  six  feet  long  and 
four  feet  wide  on  an  average,  and  is  under 
one  extreme  end  of  the  bottom.  The  fire- 
bed  is  arched,  parallel  with  the  bottom, 
and  a  space  of  one  foot  left  for  the  pas- 
sage of  the  flame.  The  flame  by  means 
of  flues  and  an  arch  of  bricks,  is  made  to 
pass  several  times  through  and  round  the 
boiler.  The  boiler  is  composed  of  seventy 
plates  of  iron,  cast  with  flanches  and  bolt- 
ed together,  so  that  the  flanch  and  bolts 
are  within  the  water,  and  is  tied  together 
by  numerous  braces.  This  boiler  con- 
sumed fifty  bushels  of  coals  and  one  half 
cord  of  wood  while  rolling  iron  twelve 
hours  at  twenty  strokes  a  minute. 
STEEL.  See  Iron. 
STEEL  YARD.  See  Mechanics. 
STENCILLING.  In  relation  to  this  art, 
we  shall  add  a  few  remarks  on  the  me- 
chanical means  for  copying  drawings. 

There  are  various  methods  by  which 
those  who  are  ignorant  of  the  art  of  draw- 
ing, may  copy  very  accurately  the  out- 
lines of  pictures,  prints,  and  drawings ; 
and  these  methods  are  often  useful  to 
those  who  can  draw,  and  to  engravers, 
when  either  great  expedition  or  great  ac- 
curacy is  required;  though  none  of  them 
should  ever  be  used  by  one  who  is  learn- 
ing to  draw. 


■  7  raci7ig  against  the  Light. 
Hold  the  drawing  you  wish  to  copy 
against  one  of  the  panes  of  the  window,  or 
have  a  pane  of  glass  put  in  a  frame,  and 
fitted  up  like  a  music-stand,  with  a  can- 
dle behind  it.  Lay  your  paper  over  the 
drawing,  and  you  will  see  all  the  lines  of 
the  original  distinctly  through  it,  by  which 
means  you  can  easily  trace  them  with  a 
pen  or  black-lead  pencil. 

To  make  Tracing-Paper. 
Mix  together  equal  parts  of  oil  of  tur- 
pentine and  drying-oil,  and  with  a  rag  rub 
it  evenly  over  some  fan,  or  tissue-paper, 
or  any  other  very  thin  paper.  Hang  it 
by  to  dry  for  a  day  or  two,  and  it  will  be 
fit  for  use.  Lay  this  over  the  print  or 
drawing  you  want  to  copy,  and  you  will 
see  every  line  distinctly  through,  so  that 
you  can  go  over  them  with  the  black-# 
lead  pencil.  If  you  wish  to  do  it  in  ink, 
you  must  mix  a  little  ox's  gall  with  the 
ink,  to  make  the  paper  take  it,  which  it 
would  not  otherwise  do,  on  account  of 
the  oil. 

To  make  Camp-Paper. 
Take  some  hard  soap,  mix  it  with  lamp- 
black ;  make  it  into  the  consistence  of  a 
jelly  with  water ;  with  this,  brush  over 
one  side  of  your  paper,  and  let  it  dry. 
When  you  use  it,put  it  between  two  sheets 
of  clean  paper,  with  its  black  side  down- 
wards, and  with  a  pin,  or  stick  with  a 
sharp  point,  draw  or  write  what  you  please 
upon  the  clean  paper ;  and  where  the 
tracer  has  touched,  there  will  be  an  im- 
pression upon  the  lowermost  sheet  of  pa- 
per, as  if  it  had  been  written  or  drawn 
with  a  pen.  It  may  be  made  of  any  co 
lour,  by  mixing  with  the  soap  black-lead, 
vermillion,  &c. 

Stencilling. 
Lay  the  print  or  drawing  you  wish  to 
have  copied,  over  a  sheet  of  paper,  and 
with  a  pin  or  needle,  prick  all  the  outline 
over  with  holes,  through  both  the  papers. 
Then  take  the  clean  paper  with  the  holes 
made  in  it,  and  lay  it  upon  the  paper  you 
wish  to  have  the  design  transferred  to, 
and  dust  it  over  with  the  powder  of  char- 
coal in  a  small  muslin  bag  ;  the  dust  will 
penetrate  through  the  holes,  and  leave 
a  correct  copy  of  the  original  upon  the 
paper. 

This  pricked  paper  will  do  again  for 
any  number  of  copies.  This  is  very  use- 
ful for  ladies,  who  work  flowers  upon 
muslin. 

STILL.  See  Distilling  Appara- 
tus. 


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STILTON  CHEESE.    Sec  Cheese. 

STONE  COAL    See  Coal. 

STONE  WARE.    See  Pottery- 

STOVE,  an  apparatus  in  which  fires 
are  made  for  various  purposes.  As  much 
has  heen  written  on  the  best  construction 
of  stoves,  for  various  purposes,  we  shall 
endeavour  to  present  our  readers  with  a 
general  view. 

On  the  subject  of"  stoves,  it  may  be  said 
in  general  terms,  that  from  the  earliest 
ages,  mankind  have  directed  their  atten- 
tion, to  the  construction  of  conveniences, 
lor  the  purpose  of  warming  rooms,  cook- 
ing-, he.  though  no  doubt  their  attempts 
were  rude,  and  their  uses  confined. 

In  the  construction  of  any  stove,  a  great 
point  is  gained,  and  ought  always  to  be 
duly  estimated,  if  the  object  of  economiz- 
ing or  saving  f  uel  is  accomplished  ;  and 
their  construction  should  be  such,  as  to 
produce  the  effect,  with  the  least  possible 
supply  of  wood  or  coal.  The  amazing 
quantity  of  heat,  which  is  usually  lost,  is 
sufficient  to  direct  our  attention  to  the 
object  before-mentioned. 

The  following  is  a  description  of  a  stove 
on  the  principles  of  the  Swedish  fire-place, 
with  head  openings,  by  Citizen  Guyton. 

The  true  principles  of  constructing  fire- 
places, so  as  to  obtain  the  greatest  heat, 
with  the  least  consumption  of  fuel,  have 
been  known  for  some  time  in  France ; 
but  diey  have  been  much  less  generally 
adopted,  than  the  necessity  for  economiz- 
ing fuel  demands.  We  see  many  fire- 
places, so  deep  as  to  consume  double  the 
quantity  of  fuel  necessary,  and  yet  heat 
the  apartment  but  faintly,  where  half  the 
expense  might  be  spared  by  altering  the 
n re-place,  according  to  Count  Kumford's 
plan. 

If  a  chimney  smoke,  instead  of  reduc- 
ing the  tunnel  to  proper  dimensions,  so 
that  descending  currents  cannot  take 
place  in  it,  scarcely  any  remedy  is  thought 
of  but  air-holes,  which  require  the  sacri- 
fice of  a  certain  quantity  of  fuel,  to  coun- 
terbalance the  effect  of  the  cold  air  conti- 
nually entering. 

The  use  of  the  Swedish  stoves  is  pro- 
bably yet  rare,  from  their  not  having  been 
constructed  on  just  principles,  or  in  the 
best  proportions,  at  their  first  introduc- 
tion. As  I  have  had  one  made,  which  ap- 
pears to  many  of  my  friends,  to  produce 
an  astonishing  effect,  in  compliance  with 
their  request,  I  shall  give  an  exact  de- 
scription of  it,  premising  however,  a  few 
principles  with  regard  to  fires. 

1.  The  heat  produced  is  proportionate 
only  to  the  air  consumed  by  the  fuel. 

2.  The  quantity  of  heat  produced  by  a 


given  quantity  of  fuel,  is  greatest  when 
the  combustion  is  most  complete. 

3.  The  combustion  is  most  complete 
when  the  fuliginous  part  of  the  fuel  is  re- 
tained longest  in  pipes,  in  which  it  may 
undergo  a  second  combustion. 

4.  Of  the  heat  produced  none  is  of  use, 
but  what  is  diffused  through  the  space 
to  be  heated,  and  retained  in  this  space. 

5.  The  temperature  in  this  space  will 
be  higher,  in  proportion  as  the  current  ot" 
air,  which  is  to  renew  and  keep  up  the 
combustion,  is  less  disposed  to  absorb  the 
heat  of  this  space  in  passing  through  it. 

Hence  we  deduce  the  following  obvious 
consequences  i 

Is  The  fire-place  must  be  kept  sepa- 
rate from  all  bodies  that  conduct  heat 
rapidly. 

2.  As  heat  can  be  produced  only  by  com- 
bustion, and  combustion  can  be  maintain- 
ed only  by  a  current  of  air,  this  current 
should  be  attracted  into  pipes,  where  it 
preserves  the  requisite  velocity,  without 
going  away  from  the  place  to  be  heated  ; 
so  that  the  heat  it  deposits  in  it,  gradually 
accumulates,  in  the  whole  of  the  isolated 
stove,  to  be  afterwards  given  out  slow- 
ly, according  to  the  laws  of  its  equili- 
brium. 

3.  When  the  wood  is  consumed  to  such 
a  point,  as  to  afford  no  more  smoke,  it  is 
of  advantage  to  stop  the  outlets  of  these 
pipes,  to  keep  in  the  heat,  which  would  be 
carried  into  the  chimney,  by  the  continu- 
ed current  of  fresh  air,  which  would  ne- 
cessarily be  of  a  lower  temperature. 

4.  We  shall  obtain  a  higher  tempera- 
ture, and  preserve  it  longer,  under  simi- 
lar circumstances,  if  we  construct  within 
aftte  stove,  or  under  the  hearth,  and  round 
me  fire-place,  pipes  in  which  the  air  de- 
rived from  without,  is  warmed  before  it 
enters  into  the  apartment,  to  support  the 
fire,  or  to  replace  what  has  been  consum- 
ed. 

These  pipes  are  what  have  been  called 
heat  openings,  (bouches  de  chaleiir,)  be- 
cause instead  of  considering  their  princi- 
pal object,  it  is  commonly  supposed,  that 
they  are  made  to  give  a  more  rapid  pas- 
sage to  the  heat  produced.  This  is  not 
totally  without  foundation,  since  the  tem- 
perature of  the  air  issuing  from  them  is 
increased  by  the  heat  it  absorbs  from  the 
stove  ;  and  on  this  account,  some  might 
be  disposed  to  neglect  them,  as  contrary 
to  the  most  essential  object,  that  of  retain- 
ing the  heat  in  it ;  but  it  is  to  be  observ- 
ed, that  we  can  shut  these  outlets  when 
we  please  ;  and  that  we  may  even  cut  off 
all  communication  with  the  external  air, 
by  means  of  a  simple  slider ;  so  that  eve- 


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ry  advantage  may  be  derived  from  them, 
without  any  inconvenience.  It  must  be 
added,  that  they  are  necessary  in  very 
close  apartments,  unless  we  would  expose 
ourselves  to  currents  of  cold  air. 

The  Swedish  stoves  are  constructed 
according  to  the  truest  principles,  and  the 
pipes  in  which  the  smoke  circulates,  are 
disposed  in  the  best  manner,  for  effecting 
its  complete  combustion.  Their  utility 
has  been  found  so  great,  that  they  have 
become  general  in  Sweden,  where  the 
winters  are  very  severe,  and  where  they 
have  diminished  the  consumption  of  wood 
one-third,  so  that  there  is  no  country 
where  the  inclemency  of  the  weather,  is 
guarded  against,  at  less  expense.  They 
have  likewise  been  employed  advantage- 
ously, with  the  necessary  variations  of 
form,  in  dye-houses,  breweries,  &c. 

Their  construction  is  by  no  means  ex- 
pensive ;  they  save  iron -work,  and  re- 
quire only  bricks  or  tiles.  These  are  re- 
commended to  be  placed  edgewise,  and 
chosen  as  thin  as  possible  for  the  inner 
walls.  The  circulating  pipes  are  to  be 
placed  so,  that  rain  falling  down  the  chim- 
ney, can  never  get  into  them.  The  me- 
thod of  using  them  is  so  easy,  that  in  the 
largest  public  buildings,  one  person  is 
sufficient  to  light  all  the  fires.  Xll  the 
wood  that  can  be  contained  in  the  fire- 
place, which  is  very  small,  is  to  be  put  in 
at  once  ;  it  is  to  be  sawed  into  pieces  of 
equal  lengths ;  and  as  soon  as  it  is  burn- 
ed, the  slider  that  stops  the  communica- 
tion of  the  circulating  pipes  with  the  chim- 
ney, is  to  be  thrust  in.  By  these  means 
all  the  heat,  which  the  fuel  is  capable  of 
producing,  remains  in  the  pipes,  and  is- 
sues out  slowly,  and  only  to  diffuse  itseli 
in  the  apartment ;  while  a  single  piece  of 
wood,  that  had  not  burned  at  the  same 
time  with  the  rest,  would  oblige  the  slide 
to  be  left  open,  and  the  current  of  air  ne- 
cessary for  its  combustion,  would  carry 
off  into  the  chimney,  the  greater  part  of 
the  heat  produced.  A  review  of  the  stove 
may  be  seen  in  Coxe's  Emporium,  vol.  1. 
No.  2,  p.  105. 

Stove  for  wanning  large  apartments. 

The  following  description  of  an  econo- 
mical mode  of  warming  large  apartments, 
by  means  of  heated  air,  is  taken  from  the 
Edinburgh  Medical  and SurgicalJournal, 
vol.  4.  It  is  in  operation  at  the  public 
hospital  of  the  town  of  Nottingham,  in 
England,  in  the  large  manufactories  of 
Nottingham  and  Derbyshire,  and  in  the 
opinion  of  Dr  Mease,  it  is  so  obviously 
preferable  to  the  mode  of  warming  rooms  \ 
by  means  of  close  iron  stoves,  that  it 
ought  to  be  adopted  wherever  pure  warm  | 


air,  regularity  of  temperature,  or  econo- 
my, are  desirable. 

These  stoves  were  first  constructed  in 
the  year  1792,  in  consequence  of  the  in- 
convenience experienced  by  the  then  ex- 
isting modes  of  warming  the  large  rooms 
in  which  manufactures  are  carried  on. 
The  open  fires  consumed  a  large  quanti- 
ty of  coal,  without  materially  heating 
the  room ;  the  people  were  therefore 
obliged  to  waste  much  time  in  warm- 
ing themselves,  and  their  health  could  not 
but  be  injured  more  or  less  by  the  alter- 
nate heats  and  chills  which  they  were 
thus  obliged  to  experience. 

The  close  iron  stoves,  so  generally  us- 
ed, had  not  this  inconvenience,  but  were, 
perhaps,  worse  upon  the  whole,  being 
dusty  and  dangerous,  and,  by  being  heat- 
ed red-hot,  which  they  were  constantly 
subject  to  be,  contributed  to  render  the 
air  unwholesome  and  offensive,  by  the 
calcination  of  the  iron,  as  well  as  by  the 
burning  of  the  various  substances  which 
are  constantly  floating  in  the  air  of  a 
room. 

To  introduce  a  large  quantity  of  the 
purest  air  which  could  be  procured  ex- 
ternally, with  simplicity,  and  to  transmit 
the  greater  part  of  the  .heat  generated, 
whatever  that  may  be,  through  the  stove, 
and  to  unite  it  with  this  air,  were  the 
leading  objects  of  the  improvement. 

In  the  common  stoves,  the  combination 
of  the  heat  that  is  generated  with  the  ex  • 
ternal  air  is  effected  very  imperfectly  ;  for 
the  air  being  a  very  bad  conductor  ot 
heat,  and  being  also  transparent,  is  inca 
pable  of  having  heat  communicated  to  it 
by  radiation ;  whence  it  follows,  that  the 
particles  of  air  only,  which  are  in  abso- 
lute contact  with  the  stove,  are  heated  by 
it — then  ascending,  in  consequence  of 
the  decrease  of  their  specific  gravity,  are 
replaced  by  others  ;  but  this  is  performed 
so  slowly,  that  the  stove  is  covered  as  it 
were  by  a  blanket,  and  very  easily  be 
comes  red-hot.  It  was  therefore  conceiv 
ed,  that  if  the  ascending  heated  air  was 
enclosed  in  a  tunnel  of  considerable  per- 
pendicular height,  and  that  if  all  the  air 
which  would  in  consequence  of  the  as- 
cending force  of  the  column,  tend  to  rush 
in  at  the  bottom,  was  made  to  impinge 
upon  all  sides  of  the  stove,  it  would  cool 
the  stove,  by  causing  a  much  larger  quan- 
tity to  come  in  contact  with  it,  be  itself 
heated  of  course,  and  thus  produce  a  ve- 
ry considerable  and  rapid  current  of  air. 

The  experiment  being  first  tried  as 
above,  in  a  building  about  200,000  cubic 
feet  of  space,  and  containing  a  great  num  - 
ber  of  windows,  wTas  found  to  answer 
completely :  but  the  stove  being  made  of 


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oast  iron,  wrought  iron  plate  was  substi- 
tuted in  subsequent  experiments,  as  be- 
ing-, for  many  reasons,  much  more  eligi- 
ble. In  some  recent  experiments,  the 
sides  of  the  Stove,  as  well  as  the  walls 
surrounding  it,  have  been  built  perpendi- 
cular, at  the  distance  of  about  seven 
inches  ;  and  wrought  iron  tubes  have  been 
inserted  into  each  hole  of  the  side  walls, 
as  well  as  in  the  arch  over  the  stove,  like 
the  nozles  of  so  many  bellows,  which,  by 
causing  every  particle  of  air  that  is  admit- 
ted, to  come  twice  in  contact  with  the 
stove,  is  believed  to  be  a  material  improve 
ment. 

A  view  of  this  stove  may  be  seen  in  the 
Archives  of  useful  Knowledge,  No.  2, 
and  also  the  new  and  portable  stove 
used  in  Edinburgh. 

Various  modes,  says  Mr.  Pettibone, 
have  been  adopted  for  warming  rooms, 
&c. 

Furnaces  have  been  made  under  the 
floor  of  a  building,  attached  to  serpen- 
tine flues,  and  very  similar  to  a  common 
kiln  for  drying  corn,  malt,  &c  — The  heat 
of  which  is  unpleasant  for  respiration ; 
also  very  difficult  to  regulate,  or  to  keep 
in  order. 

Next,  a  stove  or  cockle  has  been  en- 
closed in  a  sort  of  brick  well,  with  a 
thick  cast  iron  pipe,  leading  up  the  centre 
to  the  top  of  the  well  or  building,  and 
-there  ceiled,  that  no  smoke  could  enter 
the  well  in  contact  with  this  stove  or  coc- 
kle.— Holes  are  made  to  let  the  heat  into 
the  various  rooms,  one  above  the  other, 
but  without  success  equal  to  the  expec- 
tation. 

This  plan  was  tried  in  the  Pennsylva- 
nia hospital.  Since  which  it  has  been 
tried,  in  the  year  180.9,  in  the  hospital  at 
New-York.  At  this  place,  six  stoves  (in 
the  form  of  a  cone  or  sugar  loaf)  were 
fitted  in  wells,  and  to  the  top  or  small 
end  of  these  stoves,  a  sheet  or  cast  iron 
pipe,  as  before  mentioned. — It  is  to  be 
particularly  observed,  that  these  stoves 
and  funnels,  or  pipes,  were  heated  to  a 
red  heat,  often  from  the  fire  to  the  top  of 
the  house ;  at  which  place  the  flame  of- 
ten appeared;  and  some  of  the  stoves 
were  so  melted  as  to  spoil  them — and  the 
lowermost  rooms  were  very  cold,  while 
the  uppermost  were  amply  'heated.— This 
hospital,  as  also  that  of  Pennsylvania,  is 
under  the  particular  direction  of  gentle- 
men of  the  first  respectability,  and  are 
high  in  the  public  estimation. 

If  they  had  admitted  a  full  supply  of 
cold  external  air  into  the  well,  in  contact 
with  the  stove  and  funnel,  it  would  have 
transported  the  heat  into  the  various 


rooms :— or  if  placed  in  an  air  vessel  with- 
in the  stove  and  funnel,  so  as  to  cool  the 
.stove  and  pipe  as  much  as  possible ;  and 
have  made  the  holes  for  the  admission  of 
warm  air  much  smaller  in  the  upper 
rooms ;  and  to  have  prevented  the  sud- 
den discharge  of  the  flame  and  smoke  ;— 
they  would  have  accomplished  their  de- 
sign to  their  full  satisfaction 

Next  to  be  noticed,  is  a  stove  introduc- 
ed (by  Mr.  Pollock,  of  Boston,)  into  the 
hospital  of  New- York,  and  elsewhere, 
having  a  small  air  pipe,  not  exceeding 
two  inches  in  diameter,  through  the  cen- 
tre of  the  stove  upwards— the  stove  is  in 
shape  of  a  pillar,  with  a  square  base. 

This  air  pipe,  he  says,  is  glazed  inter- 
nally, to  preserve  the  goodness  of  the  air. 
This,  however,  has  never  yet  been  done — 
it  may  have  been  credited  by  some. 

For  this  stove,  Mr  Pollock  obtained  pa- 
tents, in  1807  and  1^08.-- -Unfortunately 
for  Mr.  Pollock,  Mr.  Oliver  Evans,  of  this 
city,  did,  in  1800,  obtain  a  patent  for  mak- 
ing stoves  or  fire-places,  with  luminous 
sides  or  doors  of  talc,  isinglass,  or  other 
fit  materials. 

Further,  Mr.  John  IT.  Gould,  in  1808, 
obtained  a  patent  for  something  which  he 
considered  an  improvement  on  grates  or 
common  fire-places.  It  is  believed  that 
he,  as  well  as  others,  were  somewhat  dis- 
appointed in  their  expectations. 

Also,  in  1808,  Mr.  Pettibone  obtained 
a  patent  for  his  air-stove,  which  was  high- 
ly approved  of. 

Mr.  Pettibone's  method  of  transporting 
heat  from  steam,  by  a  current  of  fresh 
air,  will  save  one  half  the  expense  now^ 
required  in  the  European  method ;  be- 
sides the  advantage  of  sufficient  warmth, 
agreeable  respiration,  and  ventilation. 

Mr.  Pettibone's  improvements  for 
M  anning  rooms,  or  apartments,  by  means 
of  rarefied  air,  (applicable  for  ovens,  dry- 
ing rooms,  hot,  or  green  houses,  &c.  &,c.) 
heated  with  or  without  the  application  of 
steam,  called  a  rarefying  air-stove,  con- 
sists in  the  construction  of  a  stove,  fur- 
nace, or  fire-place,  with  a  large  rarefying 
air-vessel,  or  chamber,  connected  with  the 
same,  or  things  as  hereafter  described.— 
These  air-vessels,  or  chambers,  are  so 
constructed  as  to  contain  any  kind  of 
stove,  or  steam  pipe,  or  an  air  vessel  is 
placed  in  any  stove,  so  that  the  air:  is 
heated  in  contact  with  the  outside  of  the 
stove,  or  steam  pipe,  or  within  the  stove 
in  the  air  vessel— or  within  a  steam  pipe 
or  vessel.  For  sundry  information  on  this 
subject,  see  Pettibone's  Economy  of  Fu- 
el, &c. 

On  the  subject  of  the  Franklin,  or  Ame- 


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vican  stove,  as  it  is  called,  the  following 
extract  from  the  works  of  Dr.  Franklin, 
may  be  interesting  to  the  reader. 

Speaking  of  the  invention  in  his  Letters 
on  Philosophical  Subjects,  (page  300,)  he 
says,  In  which  there  are  hollow  cavities 
made  by  iron  plates  in  the  backs,  jambs, 
and  hearths,through  which  plates  the  heat, 
passing,  warms  the  air  in  those  cavities, 
which  is  continually  coming  into  the  room 
fresh  and  warm.  The  invention  was  very 
ingenious,  and  had  many  conveniences  . 
the  room  was  warmed  in  all  parts  by  the 
air  flowing  into  it  through  the  heated  ca- 
vities ;  cold  air  was  prevented  rushing 
through  the  crevices,  the  funnel  being 
sufficiently  supplied  by  those  cavities  ; 
much  less  fuel  would  serve,  &c.  But  the 
first  expense,  which  was  very  great,  the 
intricacy  of  the  design,  and  the  difficulty 
of  the  execution,  especially  in  old  chim- 
neys, discouraged  the  propagation  of  the 
invention. 

9  Its  advantages  above  the  common  fire- 
places are, 

1.  That  your  whole  room  is  equally 
warmed,  so  that  people  need  not  crowd 
so  close  round  the  fire,  but  may  sit  near 
the  window,  and  have  the  benefit  of  the 
light  for  reading,  writing,  needle-work, 
&c.  They  may  sit  with  comfort  in  any 
part  of  the  room,  which  is  a  very  consi- 
derable advantage  in  a  large  family. 

2.  If  you  sit  near  the  fire,  you  have  not 
that  cold  draught  of  uncomfortable  air 
nipping  your  back  and  heels,  as  when  be- 
fore common  fires,  by  which  many  catch 
cold,  being  scorched  before,  and,  as  it 
were,  frozen  behind. 

3.  If  you  sit  against  a  crevice,  there  is 
not  that  sharp  draught  of  cold  air  playing 
on  you,  as  in  rooms  where  there  are  fires 
in  the  common  way.  by  which  many  catch 
cold  ;  whence  proceed  coughs,  catarrhs, 
tooth-aches,  fevers,  pleurisies,  and  many 
other  diseases. 

4.  In  case  of  sickness,  they  make  most 
excellent  nursing-rooms,  as  they  constant- 
ly supply  a  sufficiency  of  fresh  air,  so 
warmed  at  the  same  time  as  to  be  no 
ways  inconvenientor  dangerous.The  equal 
temperature,  too,  and  warmth  of  the  air 
of  the  room,  are  thought  to  be  particular- 
ly advantageous  in  some  distempers  ;  for 
it  was  observed,  in  the  winters  of  1730 
and  1736,  when  the  small-pox  spread  in 
Pennsylvania,  that  very  few  children  of 
the  Germans  died  of  that  distemper,  in 
proportion  to  those  of  the  English  ;  winch 
was  ascribed  by  some  to  the  warmth  and 
equal  temperature  of  the  air  in  their  stove- 
rooms,  which  made  the  disease  as  favour- 
able as  it  commonlv  is  in  the  West-In- 


dies. But  this  conjecture  we  submit  to 
the  judgment  of  physicians. 

5.  In  common  chimneys,  the  strongest 
heat  from  the  fire,  which  is  upwards, 
goes  directly  up  the  chimney,  and  is  lost ; 
and  there  is  such  a  strong  draught  into 
the  chimney,  that  not  only  the  upright 
heat,  but  also  the  backs,  sides,  and  down- 
ward heats,  are  carried  up  the  chimney, 
by  that  draught  of  air,  and  the  warmth 
given  before  the  fire,  by  the  rays  that 
strike  out  towards  the  room,  is  continual- 
ly driven  back,  crowded  into  the  chimney, 
and  carried  up  by  the  same  draught  of 
air;  but  here  the  upright  heat  strikes  and 
heats  the  top  plate,  which  warms  the  air 
above  it,  and  that  comes  into  the  room. 
1'he  heat,  likewise,  which  the  fire  com 
municates  to  the  sides,  back,  bottom,  and 
air  box,  is  all  brought  into  the  room  ;  for 
you  will  find  a  constant  current  of  warm 
air  coming  out  of  the  chimney-corner  in- 
to the  room.  Hold  a  candle  just  under 
the  mantle-piece,  or  breast  of  your  chim- 
ney, and  you  will  see  the  flame  bent  out- 
wards. By  laying  a  piece  of  smoking  pa- 
per on  the  hearth,  on  either  side,  you 
may  see  how  the  current  of  air  moves, 
and  where  it  tends,  for  it  will  turn  and 
carry  the  smoke  with  it. 

6.  Thus,  as  very  little  of  the  heat  is 
lost  when  this  fire-place  is  used,  much 
less  wood  or  fuel  will  serve  you,  which  is 
a  considerable  advantage  where  wood  is 
dear. 

People,  who  have  used  these  fire- 
places, differ  much  in  their  accounts  of 
the  wood  saved  by  ihem  ;  some  say  five- 
sixths,  others  three-fourths,  and  others 

j  much  less.  This  is  owing  to  the  great 
difference  there  was  in  their  former  fires  ; 

,  some  (according  to  the  different  circum- 
stances of  their  rooms  and  chimneys) 
having  been  used  to  make  very  large, 
others  middling,  and  others  of  a  pitire 
sparing  temper  very  small  ones ;  while  in 
these  fire-places  (their  size  and  draught 

I  being  nearly  the  same)  .the  consumption 
is  more  equal.  I  suppose,  taking  a  num- 
ber of  families  together,  that  two-thirds, 
or  half  the  wood,  at  least,  is  saved.  My 
common  room,  I  know,  is  made  twice  as 
warm  as  it  used  to  be  with  a  quarter  the 
wood  I  formerly  consumed  there. 

7.  When  you  burn  candles  near  this 
fire-place,  you  will  find  that  the  flame 
burns  quite  upright,  and  does  not  blare 
and  run  the  tallow  down,  by  drawing  to- 
wards the  chimney,  as  in  common  fire- 
places. 

8.  This  fire-place  cures  most  smoky 
chimnies,  and  thereby  preserves  both  the 
ey*s  and  furniture. 


STO 


STO 


9.  It  prevents  the  fouling  of  chimneys  ; 
much  of  the  lint  and  dust,  that  contribute  ! 
to  foul  a  chimney,  being  by  the  low  arch  j 
obliged  to  pass  through  the  flame,  where  i 
it  is  consumed :  then,  less  fuel  being  j 
burnt,  there  is  less  smoke  made.    Again,  I 
by  hanging  on  the  blower,  a  flame  is  soon  j 
produced,  and,  in  consequence,  the  same  j 
fuel  does  not  yield  so  much  smoke,  as  if , 
burnt  in  a  common  chimney ;  for,  as  soon 
as  flame  begins,  smoke  in  proportion 
ceases. 

10.  And  if  a  chimney  should  be  foul,  it 
is  much  less  likely  to  take  fire ;  if  it  should 
take  fire,  it  is  easily  stifled  and  extin- 
guished. 

11.  A  fire  may  be  very  speedily  made 
in  this  fire  place  by  the  help  of  the  above- 
mentioned  blower.  With  all  these  con- 
veniences, you  do  not  lose  the  pleasing 
sight  nor  use  of  the  fire.. 

The  objections  made  against  the  use  of 
this  stove,  have  been  abolished. 

On  the  nature  of  warmth  the  Dr.observes, 
the  maxim  that  warm  rooms  make  people 
tender, and  apt  to  catch  cold,  is  a  mistake  as 
great  as  it  is  general.    We  have  seen,  in 
the  preceding  pages,  how  the  common 
rooms  are  apt  to  give  cold ;  but  he  affirms 
from  his  own  experience,  and  that  of  his 
family  and  friends,  who  have  used  warm 
rooms  for  these  four  winters  past,  that  by 
the  use  of  such  rooms  people  are  render- 
ed less  liable  to  take  cold,  and,  indeed, 
actually  hardened.   If  sitting  warm  in  a 
room  made  one  subject  to  take  cold  on 
going  out,  lying  warm  in  bed  should,  by 
a  parity  of  reasoning,  produce  the  same 
effect  when  we  rise  ;  yet  we  find  we  can 
leap  out  of  the  warmest  bed  naked,  in  the 
coldest  morning,  without  any  such  dan- 
ger, and  in  the  same  manner  out  of  warm 
clothes  into  a  cold  bed.    The  reason  is, 
that  in  these  cases  the  pores  all  close  at 
once,  the  cold  is  shut  out,  and  the  heat 
within  augmented,  as  we  soon  after  feel 
by  the  glowing  of  the  flesh  and  skin. 
Thus,  no  one  was  ever  known  to  catch 
cold  by  the  use  of  a  cold  bath ;  and  are 
not  cold  baths  allowed  to  harden  the  bo- 
dies of  those  that  use  them  ?  x\re  they  not 
therefore  frequently  prescribed  to  the  ten- 
derest  constitutions  ?   Now,  every  time 
you  go  put  of  a  warm  room  into  the  free- 
zing cold  air,  you,  as  it  were,  plunge  into 
a  cold  bath,  and  the  effect  is  in  proportion 
the  same;  for,  though  perhaps  you  may 
feel  somewhat  chilly  at  first,  you  find  in  a 
little  time  your  bodies  hardened  and 
strengthened,  your  blood  is  driven  round 
with  a  brisker  circulation,  and  a  comfort- 
able, steady,  uniform,  inward  warmth  suc- 
ceeds that  equal  outward  warmth  vou 


first  received  in  the  room.  Farther  to 
confirm  this  assertion,  we  instance  the 
Swedes,  the  Danes,  and  the  Russians; 
these  nations  are  said  to  live  in  rooms, 
compared  to  ours,  as  hot  as  ovens ;  yet, 
where  are  the  hardy  soldiers,  though  bred 
in  their  boasted  cool  houses,  that  can  like 
these  people,  bear  the  fatigues  of  a  win- 
ter campaign  in  so  severe  a  climate,  march 
whole  days  up  to  the  neck  in  snow,  and 
at  night  entrench  in  ice  as  they  do  ? 

The  mention  of  those  northern  nations 
(says  the  doctor)  puts  me  in  mind  of  a 
considerable  public  advantage  that  may 
arise  from  the  general  use  of  these  fire- 
places It  is  observable,  that,  though 
these  countries  have  been  well  inhabited 
for  many  ages,  wood  is  still  their  fuel,  and 
yet  at  no  very  great  price ;  which  could 
not  have  been,  if  they  had  not  universally 
used  stoves,  but  consumed  it  as  we  do,  in 
great  quantities,  by  open  fires.  By  the 
help  of  this  saving  invention,  our  wood 
may  grow  as  fast  as  we  consume  it,  and 
our  posterity  may  warm  themselves  at  a 
moderate  rate,  without  being  obliged  to 
fetch  their  fuel  across  the  Atlantic  ;  as,  if 
pit-coal  should  not  be  here  discovered, 
(which  is  an  uncertainty,)  they  must  ne  ■ 
cessarily  do. 

We  leave  it  to  the  political  arithmeti- 
cian to  compute  how  much  money  will, 
be  saved  to  a  country  by  its  spending  two 
thirds  less  of  fuel;  how  much  labour 
saved  in  the  cutting  and  carriage  of  it ; 
how  much  more  land  may  be  culti- 
vated ;  how  great  the  profit  by  the  addi- 
tional quantity  of  work  done,  in  those 
trades  particularly  that  do  not  exercise 
the  body  so  much,  but  that  the  workmen 
are  obliged  to  run  frequently  to  the  fire 
to  warm  themselves ;  and  to  physicians, 
to  say  how  much  healthier  thick-built 
towns  and  cities  will  be,  now  half  suffo- 
cated with  sulphureous  smoke,  when  so 
much  less  of  that  smoke  shall  be  made, 
and  the  air  breathed  by  the  inhabitants 
be  consequently  so  much  purer. 

Franklin  Stoves  improved  ;  as  also  the  com- 
mon Fire-place. 
"  The  common  chimney,  or  open  fire- 
place, or  grate  ;  also  the  common  open- 
stove,  (called  the  Franklin  stove,  or  fire- 
place,) says  Mr.  Pettibone,  is  very  much 
improved,  by  placing  an  air-vessel  upon 
it,  and  sometimes  a  hollow  cylinder  in 
place  of  a  back  log  in  it,  or  just  above  the 
fire.  The  flame  and  smoke,  by  passing 
round  the  air-vessel  in  a  reverberatory 
manner,  communicates  their  heat  to  the 
air  in  the  air-vessel ;  which  air  is  intro- 
duced into  the  air-vessel,  from  the  exte- 


STO 


STO 


rior  atmosphere,  as  before  described,  and 
let  into  the  room,  or  to  an  adjoining  room, 
irom  the  sides  or  top  of  the  stove." 

A  Mr  Sharp  procured  a  patent,  seve- 
ral years  since,  says  Dr  Willich,  for  cer- 
tain improvements,  which  are  calculated 
to  obviate  the  inconveniences  (of  Frank- 
lin's stoves.)  Thus,  by  adding'  a  funnel 
to  the  top,  these  fire-places  can  be  adapt- 
ed to  any  chimnies  ;  and,  if  the  funnel  be 
lengthened,  it  may  be  accommodated  to 
libraries,  ball-rooms,  or  other  buildings, 
which  have  not  the  advantage  of  a  chim- 
ney. Mr.  Sharp's  stove-grates  are  pro- 
vided with  a  hollow  base  ;  in  consequence 
of  whicl),  he  is  enabled  to  apply  them, 
•without  any  additional  brick-work,  more 
effectually  to  the  purpose  of  healing 
rooms,  than  is  practicable  with  those  on 
Franklin's  construction  :  at  the  same  time, 
by  his  alterations  in  the  air-box,  a  krger 
portion  of  air  is  introduced.  Our  limits 
permit  us  only  to  add,  that  Mr  Sharp's 
stove -grates  may  be  accommodated  to 
every  building,  whether  public  or  private  : 
and  we  refer  the  reader  to  his  "  Account 
of  the  Air  stove -Grates"  &c.  8vo. 

In  June,  1796,  a  patent  was  granted  to 
Mr.  William  Whittington,  for  his  inven- 
tion of  a  Portable  Baking  Stove.  The  pa- 
tentee asserts,  that  the  contrivance  is  cal- 
culated for  baking  all  kinds  of  bread,  par- 
ticularly that  prepared  of  oats,  with  a 
cheapness  and  facility  not  hitherto  expe- 
rienced. It  may  be  manufactur  ed  from 
any  metal,  or  even  from  clay,  of  any  size 
or  shape ;  and  either  with  or  without  an 
oven  :  the  door  for  supplying  fuel,  toge- 
ther with  the  pipe  or  flue  for  carrying  off' 
the  smoke,  may  be  fixed  in  any  part  of  the 
stove.  Besides,  this  machine  may  be 
used  in  any  situation,  whether  on  land  or 
at  sea  ;  being  easily  portable,  and  requir- 
ing only  one-fifth  part  of  the  fuel,  consum- 
ed in  the  common  way ;  as  it  may  be  easi- 
ly heated  with  coke,  coals,  wood  char- 
coal, or  any  other  substance.  For  a  more 
diffuse  account  of  such  contrivance,  the 
reader  will  consult  the  12th  vol.  of  the 
Repertory  of  Arts,  &.c.  where  it  is  illus- 
trated with  an  engraving. 

A  patent  was  likewise  granted  to  Mr. 
Edward  Walker,  for  a  portable  stove  or 
kitchen  ;  to  facilitate  the  processes  of 
cooking,  or  dressing  provisions.  The 
whole  is  manuactured  of  either  cast  or 
wrought  iron ;  having  a  fire-place  in  its 
centre,  which  is  inclosed  by  a  door:  be- 
neath is  an  ash-hole ;  and  on  each  side, 
there  is  a  closet,  one  of  which  may  be  em- 
ployed for  baking  ;  the  other  will  contain 
two  spits,  with  racks,  &c.  complete ;  the 
top  may  be  used  as  a  broiling-plate,  heal- 
ed by  the  same  fire ;  while  the  smoke  is 


carried  off  through  an  iron  funnel,  having 

a  smoke-jack  for  the  purpose  of  turning 
the  spits.  A  more  complete  idea  of  this 
stove,  may  be  obtained  from  the  15th  vol. 
of  the  Repertory  of  Arts  and  Sciences,  &c. 
where  the  specification  is  illustrated  with 
an  engraving. 

Description  of  a  kitchen  stove  ;  by  Sa- 
muel Dickey.  Communicated  to  the  Agri- 
cultural Society  of  Philadelphia. 

The  general  principles  of  this  kitchen 
stove  are, 

1.  Enclosing  it  with  the  pots  connected 
with  it,  in  some  covering  that  is  a  non- 
conductor of  heat,  by  which  the  speedy 
evaporation  of  the  heat  is  prevented,  and 
its  power  is  concentrated  more  intensely 
upon  the  pots  and  ovens,  used  in  cooking. 

2.  Drawing  off  the  fire  from  the  fur- 
nace of  the  stove,  through  openings  in  the 
stove  plates,  that  may  be  closed  at  plea- 
sure with  sliding  dampers,  and  by  means 
of  the  covering  that  surrounds  the  stove, 
conveying  it  round  pots  set  close  to  these 
openings,  and  returning  \t  back  upon  the 
ovens,  for  the  purpose  of  increasing  the 
heat  in  them. 

3.  Allowing  the  fire  to  pass  into  the 
oven  of  the  stove,  through  an  opening  in 
the  bottom  plate  of  the  oven,  immediate- 
ly above  the  fire,  so  as  to  bear  with  all  its 
force  on  a  tea-kettle,  or  any  small  vessel 
set  into  the  oven,  for  the  purpose  of  boil- 
ing. 

4-  Receiving  the  heat  into  a  large  recep- 
tacle of  sheet-iron  placed  above  the  stove, 
through  which  it  may  pass  into  the  kit- 
chen, for  the  purpose  of  warming  it. 

Every  peison  who  thinks  upon  the  sub. 
ject,  is  sensible  of  the  vast  waste  of  fuel, 
that  takes  place  in  cooking  at  ar\  open 
fire.  The  introduction  of  a  ten  plate 
stove,  is  certainly  economical,  and  adds 
much  to  the  comfort  of  the  kitchen.  But 
still  there  is  both  a  manifest  expense  and 
trouble,  in  keeping  up  two  fires.  One  ought 
to  serve  all  purposes.  The  stove  or  clos- 
ed fire-place  above  described,  docs  all  the 
business  of  the  kitchen  with  one  fire,  and 
a  great  saving  of  fuel,  as  the  same  heat 
that  bakes  and  boils,  is  afterwards  emit- 
ted to  warm  the  kitchen,  with  nearly  as 
good  effect,  as  if  it  had  performed  no  pre- 
vious service.  Besides  the  saving  of  wood, 
tHere  is  perhaps  as  great  a  saving  of  la- 
.bour,  by  the  facility  with  which  the  cook- 
ing business  can  be  executed.  The  ovens 
are  always  warm,  when  there  is  fire  in 
the  stove'  The  fire  can  be  turned  off,  and 
on  the  pots  in  an  instant,  without  the 
trouble  of  moving  them  ;  and  the  cook  is 
never  exposed  to  the  scorching  heat  of  an 
open  fire.  This  stove  is  set  with  the  most 
advantage,  in  the  fire-place  of  the  kitchen. 


STO 


SLG 


The  front  of  it  extending  about  twelve 
inches  out,  from  the  breast  of  the  chim- 
ney, so  as  to  admit  the  apparatus  for  heat- 
ing the  kitchen,  to  stand  out  in  front  of 
the  mantle.  The  throat  of  the  chimney, 
should  be  stopped  in  winter,  but  furnish- 
ed with  a  sliding  shutter,  to  be  opened 
occasionally,  so  as  to  allow  the  steam  from 
the  boiling  pots  to  escape,  without  incom- 
moding the  kitchen. 

For  further  information,  see  the  Me- 
moirs of  the  Society. 

Jl  Column  Stove  of  JWr.  Pcttibone. 
"  For  the  purpose  of  ornament  and  uti- 
lity, a  stove,  or  rather  a  reservoir  of  heat, 
may  be  made  of  iron,  earthen  ware,  brick 
or  stone,  to  represent  a  column,  in  the 
centre  of  which,  a  pipe  or  flue  is  placed. 
The  smoke  is  made  to  pass  round  the  Hue, 
from  the  bottom  to  the  top,  in  a  spiral  or 
serpentine  direction,  which  is  done  by 
means  of  bricks,  so  placed  as  to  form  a 
flue,  to  convey  the  smoke  in  this  way. 
The  stove  or  column,  is  furnished  with 
tubes  or  boxes,  as  before  described. — 
When  the  smoke  has  risen  to  the  top  of 
the  column,  it  is  carried  off'  as  in  the  com- 
mon stove,  or  may  be  made  to  turn  down 
through  the  centre  of  the  air-flue.  In 
this  stove  or  reservoir,  there  is  no  ap- 
pearance of  pipes,  or  flues,  from  which 
circumstance,  it  may  be  so  decorated  as 
to  render  it  ornamental  5' 

Jl  Dome  Stove,  qfJIr.  Petti  bone. 

"  I  have  constructed  a  cylindrical  stove, 
it  being  composed  of  two  or  more  cylin- 
ders, one  within  the  other)  standing  per- 
pendicular, or  lying  horizontally-  When 
it  is  made  to  stand  perpendicular,  it  re- 
sembles a  dome.  1  sometimes  made  them 
to  resemble  a  common  coffee  pot,  of  iron, 
brass,copper,  potter's  clay,  earthen  ware, 
glass,  &c.  excepting  it  has  2  spouts  and  no 
handle  ;  the  spouts  being  opposite  to  each 
other,  and  servers  reservoirs  or  places  to 
put  in  fuel,  without  disturbing  the  fire,  as 
in  the  common  stove.  When  lying  hori- 
zontally, the  fuel  is  put  in  at  one  end,  or 
at  the  side  or  sides,  (similar  to  a  common 
air-furnace,)  into  the  inner  or  outer  cylin- 
der ;  and  the  air  being  heated  in  the  in- 
ner, or  between  the  two  cylinders.  When 
the  air  is  heated  between  the  cylinders, 
the  flame  and  smoke  circulate  in  the  in- 
ner one,  and  the  warm  air  is  suffered  to 
escape  at  the  top  of  the  outward  dome  or 
cylinder,  through  ornamental  figures, such 
as  urns  and  blazers  :  to  this  dome  is  often 
applied  the  circular  grate." 

It  may  be  proper  to  notice,  that  sundry 
other  improvements  have  been  made,  for 
VOL.  II. 


the  purpose  of  warming  rooms,  cooking, 
and  economizing  fuel.  Of  the  stoves  for 
the  purpose  of  the  kitchen,  none  is  more 
really  useful  than  the  improvement  of  Mr. 
Abbot,  which  is  in  general  use  through- 
out the  city  ;  and  which,  when  employed 
serves  not  only  to  perform  the  domestic 
uses  of  the  kitchen,  almost  at  one  and 
the  same  time,  (from  the  arrangement  of 
the  pots,  8cc.)  but  is  also  considerable 
saving  in  fuel-    See  Fuel,  economy  of. 

STUCCO. — Higgins's  patent  stucco  is 
a  conpound  of  14  or  15  lbs.  of  choice 
lime,  14  lbs.  of  bone  ashes,  finely  pulve- 
rised, and  98  lbs.  of  clean  sand,  fine  or 
coarse,  according  to  the  work  intended, 
mixed  up  into  mortar  as  quickly  as  pos- 
sible with  lime  water,  and  used  as  soon  as 
made.    See  Cement. 

SUBLIMATION.  Sublimation  is  in  the 
dry  way  what  distillation  is  in  the  moist. 
Thus,  if  a  small  quantity  of  sal  ammoniac 
is  put  into  a  flask,  and  heat  is  applied  at 
the  bottom;  the  entire  salt  rises  in  the 
form  of  white  smoke,  and  condenses  in 
the  upper  part  of  the  flask  in  the  form  of 
minute  crystalline  particles,  which  is  a 
sublimate. 

Sublimation  is  conveniently  performed 
in  the  small  way  in  common  flasks,  espe- 
cially the  Florence  oil  flasks,  which  being 
of  green  glass,  bear  a  low  red  heat  very 
well. 

In  the  large  way,  as  in  the  making  of 
camphor  or  sal  ammoniac,  it  is  also  per- 
formed in  very  large  glass  globes  or  ear- 
then cucurbites,  or  sometimes,  though 
rarely,  in  a  series  of  earthen  vessels,  call- 
ed Aludels. 

SUGAR,  is  a  constituent  part  of  vege- 
tables, existing  in  considerable  quantities 
in  a  number  of  plants.  It  is  afforded  by 
the  maple,  the  birch,  wheat,  and  Turkey 
corn.  Margraaf  obtained  it  from  the  roots 
of  beet,  red  beet,  skirret,  parsneps,  and 
dried  grapes.  The  process  of  this  che- 
mist consisted  in  digesting  these  roots, 
rasped  or  finely  divided,  in  alcohol  This 
fluid  dissolves'  the  sugar,  and  leaves  the 
extractive  matter  untouched,  which  falls 
to  the  bottom. 

In  Canada  the  inhabitants  extract  sugar 
from  the  maple.  At  the  commencement 
of  spring  they  heap  snow  in  the  evening 
at  the  foot  of  the  tree,  in  which  they  p 
viously  make  apertures  for  the  passage  of 
the  returning  sap.  Two  hundred  pounds 
of  this  juice  afford  by  evaporation  fifteen 
of  a  brownish  sugar.  The  quantity  pre- 
pared annually  amounts  to  fifteen  thou- 
sand weight.    See  Maple  Sugar. 

From  frequent  trials  of  this  sugar,  if 
does  not  appear  to  be  in  any  respect  infe- 
rior to  that  of  the  West  Indies.   It  is  pre* 
3  II 


SUtt 


SUG 


pared  at  a  time  of  the  year  when  neither 
insect  nor  the  pollen  of  plants,  exisis  to 
vitiate  it,  as  is  the  case  with  common  su- 
gar. From  calculations  grounded  on  facts 
it  is  ascertained,  that  America  is  now  ca- 
pable of  producing  a  surplus  of  one-eighth 
more  than  its  ow  n  consumption  ;  that  is, 
on  the  whole,  about  135,000,000  pounds  j 
which  in  the  country  may  be  valued  at  fif- 
teen pounds  weight  for  one  dollar. 

The  Indians  likewise  extract  sugar  from 
the  pith  of  the  bamboo. 

The  great  sources  of  sugar  are,  the 
common  juice  or  sap  of  plants,  as  in  the 
sugar-cane,  and  maple  sap;  the  ripe  fruit, 
as  in  the  grape,  date,  fig,  in  all  of  which 
it  exudes  and  effloresces  on  the  surface, 
when  kept  dry ;  and  the  root  (though  in 
much  smaller  quantity)  as  in  the  beet  and 
parsnip.  It  is  also  elaborated  during  the 
first  germination  of  most  grains,  particu- 
larly barley,  as  is  seen  in  the  process  of 
malting. 

The  Cochin  Chinese,  prepare  a  very  ex- 
cellent moist  sugar  remarkably  cheap,  by 
a  very  simple  process  which  acts  similar 
to  the  claying.  The  grained  sugar  after 
the  gross  syrup  has  drained  off  from  it, 
and  it  has  become  considerably  solid,  is 
placed  in  layers  of  about  an  inch  thick, 
under  layers  of  equal  dimensions  of  the 
herbaceous  trunk  of  the  plantain  tree,  the 
watery  juices  exuding  from  which,  act 
like  claying,  and  leave  the  sugar  very 
white,  and  porous  like  a  honeycomb.  It 
is  sufficiently  pure  to  dissolve  in  water 
without  leaving  any  sediment. 

The  beet  has  lately  been  much  culti- 
vated in  Germany,  for  the  purpose  of  ex- 
tracting sugar  from  its  root.  For  this  the 
roots  are  taken  up  in  autumn,  washed 
clean,  wiped,  sliced  lengthwise,  strung  on 
threads,  and  hung  up  to  dry.  From  these 
the  sugar  is  extracted  by  maceration  in  a 
small  quantity  of  water;  drawing  off  this 
up.m  fresh  roots,  and  adding  fresh  water 
to  the  first  roots,  which  is  again  to  be  em- 
ployed  the  same  way,  so  as  to  get  out  all 
their  sugar,  and  saturate  the  water  as 
much  as  possible  with  it,  This  water  is 
to  be  strained  and  boiled  dow  n  for  the 
sugar. 

Some  merely  express  the  juice  from  the 
fresh  roots,  and  boil  this  down ;  others 
boil  the  roots  •  but  the  sugar  extracted 
in  either  of  these  ways  is  not  equal  in  qua- 
lity to  the  first. 

Professsor  Lampadius  obtained  from 
110  lbs.  of  the  roots,  4  lbs.  of  well  grained 
white  powder  sugar;  and  the  residuum  af- 
forded 7  pints  of  a  spirit  resembling  rum. 
Achard  says  that  about  a  ton  of  roots  pro- 
duced him  a  hundred  pounds  of  raw  su- 
gar, which  gave  fifty-five  pounds  of  re- 


fined sugar,  and  twenty-five  pounds  of 
treacle. 

Sugar  is  made  in  large  quantities  in 
France  from  this  source. 

The  skirret  root  was  treated  in  the  fol- 
lowing manner  without  alcohol,  with  a 
view  of  extracting  the  sugar.  A  quantity 
of  it  was  chopped  small,  bruised  in  a  mor- 
tar, and  the  juice  expressed  through  a 
cloth  bag-,  and  the  pulp  was  again  mois- 
tened with  water,  and  expressed  to  get 
out  all  the  saccharine  liquor  The  whole 
liquor  w  as  then  kept  at  rest  for  forty-eight 
hours,  in  a  cool  cellar,  by  which  most  of 
the  feculence  subsided,  and  the  clear  li- 
quor was  carefully  drawn  off'.  The  au. 
thor  lays  much  stress  on  this  part  of  the 
process,  which,  if  it  is  not  done  properly, 
considerably  hinders  the  subsequent  pro- 
duction of  the  sugar.  The  clear  liquor 
was  then  heated  in  a  copper  pan,  clarified 
with  white  of  egg,  and  boiled  down  to  the 
consistence  of  thick  syrup,  and  kept  in 
this  state  for  about  six  months  in  a  warm 
place,  by  which  it  concreted  into  a  semi- 
fluid crystalline  mass,  composed  of  im- 
pure crystals  of  sugar,  and  a  good  deal  of 
syrup.  The  whole  mass  was  then  a  little 
warmed,  to  give  the  syrup  a  little  more 
fluidity,  and  poured  into  a  funnel-shaped 
vessel  of  tinned  iron,  with  holes  at  the 
sides  and  bottom,  and  set  by,  in  a  warm 
place ;  by  which,  after  a  considerable 
time,  the  impure  uncongealable  syrup 
slowly  filtered  to  the  bottom,  leaving  the 
purer  saccharine  part  in  the  form  of  a 
brown  granular  mass.  The  latter  was 
then  redissoived  in  water,  again  clarified 
with  white  of  egg,  strained,  boiled  with  a 
little  lime,  again  strained,  and  then  eva- 
porated to  a  thick  consistence,  and  stirred 
till  cold.  A  sugary  viscid  mass  still  purer 
than  the  last  was  thus  obtained,  which,  on 
being  kept  for  a  week  in  a  funnel-shaped 
pot  with  a  single  hole  at  bottom,  plugged 
tip,  congealed  into  a  grained  sugar  equal 
to  good  muscovado,  from  which  a  syrup 
separated  and  dropped  through  when  the 
plug  was  withdrawn. 

Such  is  the  process, of  this  chemist  to 
obtain  a  sugar  from  the  skirret  root,  and 
he  proceeded  in  the  same  manner  with  the 
white  and  red  beet  root,  and  with  the 
same  success.  He  further  observes,  that 
he  rasped  the  beet  roots,  they  being-  harder 
than  the  skirrett,  that  the  mucilaginous 
deposit  from  the  beets  was  browner  and 
less  copious  than  from  the  skirret;  the 
sugar  from  the  white  beet  was  the  most 
abundant  and  the  purest,  and  that  from 
the  red  beet  was  the  least  so.  The  muci- 
lage or  sediment  from  the  skirret  washed 
with  cold  water  and  purified,  yielded  a 
very  good  white  farina. 


sue; 


SUG 


But  the  sugar  which  is  so  universally 
used  is  afforded  by  the  sugar-cane  (arun- 
do  saccharifera)  which  is  raised  in  tropical 
climates.  When  this  plant  is  ripe,  it  is  cut 
down,  and  crushed  by  passing  it  between 
iron  cylinders  placed  perpendicularly,  and 
moved  by  water  or  animal  strength.  The 
juice  which  flows  out  by  this  strong  pres- 
sure is  received  in  a  shallow  trough  placed 
beneath  the  cylinder.  This  juice  is  call- 
ed in  the  French  sugar-colonies  vesou  ; 
and  the  cane,  after  having  undergone  this 
pressure,  is  called  begasse.  The  juice  is 
more  or  less  saccharine,  according  to  the 
rtature  of  the  soil  on  which  the  cane  has 
grown,  and  the  weather  that  has  predo- 
minated during  its  growth.  It  is  aqueous 
when  the  soil  or  the  weather  has  been  hu- 
mid ;  and  in  contrary  circumstances  it  is 
thick  and  glutinous. 

The  juice  of  the  cane  is  conveyed  into 
boilers,  where  it  is  boiled  with  wood  ashes 
and  lime.  It  is  subjected  to  the  same  ope- 
ration in  three  several  boilers,  care  being 
taken  to  remove  the  scum  as  it  rises.  In 
this  state  it  is  called  syrup ;  and  is  again 
boiled  with  lime  and  alum  till  it  is  suffi- 
ciently concentrated,  when  it  is  poured 
into  a  vessel  called  the  cooler.    In  this 
vessel  it  is  agitated  with  wooden  stirrers, 
which  breaks  the  crust  as  it  forms  on  the 
surface.    It  is  afterwards  poured  into 
casks,  to  accelerate  its  cooling,  and  while 
it  is  still  warm,  it  is  conveyed  into  bar- 
rels standing  upright  over  a  cistern,  and 
pierced  through  their  bottoms  with  seve- 
ral holes  stopped  with  cane.    The  syrup, 
which  is  not  condensed,  filters  through 
these  canes  into  the  cissern  beneath,  and 
leaves  the  sugar  in  the  Siate  called  coarse 
sugar,  or  muscovado.    This  sugar  is  yel- 
low and  fat,  and  is  purified  in  the  islands 
in  the  following  manner:  The  syrup  is 
boiled,  and  poured  into  conical  earthen 
vessels,  having  a  small  perforation  at  the 
apex,  which  is  kept  closed..    Each  cone, 
reversed  on  its  apex,  is  supported  in  ano- 
ther earthen  vessel.  The  syrup  is  stirred 
together,  and  then  left  to  crystallize.  At 
the  end  of  fifteen  or  sixteen  hours,  the 
hole  in  the  point  of  each  cone  is  opened, 
that  the  impure  syrup  may  run  out.  The 
base  of  these  sugar  loaves  is  then  taken 
out,  and  white  pulverized  sugar  substi- 
tuted in  its  stead ;  which  being  well  press- 
cd  down,  the  whole  is  covered  with  clay, 
moistened  with  water.    This  water  filters 
through  the  mass,  carrying  the  syrup  with 
it  which  was  mixed  with  the  sugar,  but 
which  by  this  management  flows  into  a 
pot  substituted  in  ihe  place  of  the  first. 
This  second  fluid  is  called  fine  syrup. 
Care  is  taken  to  moisten  and  keep  the 


clay  to  a  proper  degree  of  softness,  as  it 
becomes  dry.  The  sugar  loaves  are  af- 
terward taken  out,  and  dried  in  a  stove 
for  eight  or  ten  days ;  after  which  they 
are  pulverized,  packed,  and  exported  to 
Europe,  where  they  are  still  farther  pu- 
rified. 

The  operation  of  the  French  sugar  re- 
finers consists  in  dissolving  the  cassonade 
or  clayed  sugar,  in  lime  water.  Bullocks' 
blood  is  added,  to  promote  the  clarifying ; 
and,  when  the  liquor  begins  to  boil,  the 
heat  is  diminished,  and  the  scum  carefully 
taken  off.  It  is  in  the  next  place  concen- 
trated by  a  brisk  heat;  and,  as  it  boils  up, 
a  small  quantity  of  butter  is  thrown  in,  to 
moderate  its  agitation.  When  the  boiling 
is  sufficiently  effected,  the  fire  is  put  out, 
the  liquor  is  poured  into  moulds,  and  agi- 
tated, to  mix  the  syrup  together  with  the 
grain  sugar  already  formed.  When  the 
whole  is  cold,  the  moulds  are  opened,  and 
the  loaves  are  covered  with  moistened 
chry,  which  is  renewed  from  time  to  time 
till  the  sugar  is  well  cleansed  from  its  sy- 
rup. The  loaves  being  then,  taken  out  of 
the  moulds,  are  carried  to  a  stove,  where 
they  are  gradually  heated  to  145"  Fahr. 
They  remain  in  this  stove  eight  days,  after 
which  they  are  wrapped  in  blue  paper  for 
sale. 

The  several  syrups,  treated  by  the  same 
methods,  afford  sugars  of  inferior  quali- 
ties ;  and  the  last  portion,  which  no  longer 
affords  any  crystals,  is  sold  by  the  name 
of  molasses.  The  Spaniards  use  this  mo- 
lasses in  the  preparation  of  sweetmeats. 

A  solution  of  sugar,  much  less  concen-  • 
trated  than  that  we  have  just  been  speak- 
ing of,  when  at  rest  lets  fail  crystals,  which 
affect  the  form  of  tetrahedral  prisms,  ter- 
minated by  dihedral  summits,  and  known 
by  the  name  of  sugar-candy. 

The  preceding  account  of  the  manufac- 
ture of  sugar  in  the  colonies  is  chiefly  ex- 
tracted from  Chaptal.  The  following  more 
ample  account  is  taken  from  Edwards's 
History  of  the  West  Indies,  the  authority 
of  which  is  indubitable. 

The  sugar-cane  is  a  jointed  reed,  which 
terminates  in  leaves  or  blades,  the  edges 
of  which  are  finely  and  sharply  serrated. 
The  body  of  the  cane,  though  brittle,  is 
strong,  and  when  ripe,  is  of  a  fine  straw 
colour  inclinable  to  yellow.  It  likewise 
contains  a  soft  pithy  substance,  which  is 
replete  with  juice  of  a  very  agreeable 
taste.  The  general  dis<  ,\nce  between  each 
joint  of  the  cane  is  from  one  to  three 
inches  in  length,  and  from  half  an  inch  to 
an  inch  in  diameter;  and  the  general 
height  (the  flag  part  being  excluded)  is 
from  three  feet  and  a  half  to  seven  feet 


SUG 


SUG 


In  very  rich  lands,  too,  the  stool  or  root 
has  been  known  to  put  forth  upward  of 
one  hundred  suckers  or  shoots. 

To  bring-  a  plant  of  this  rank  and  suc- 
culent nature  to  perfection,  no  land  can 
be  too  rich;  and  the  ashy  loam  of  St. 
Christopher's  appears  to  be  the  best  soil 
hitherto  known,  for  the  production  of  su- 
gar of  the  finest  quality,  and  in  the  largest 
proportion.  The  next  to  this  in  excel- 
lence is  the  soil  which  in  Jamaica  is  called 
brick-mould.  It  is  a  deep,  warm,  and 
meilow,  hazel  earth,  which  is  easily  work- 
ed, and  which  in  the  wettest  season  sel- 
dom requires  trenching-.  In  a  very  fine 
season,  plant  canes  (which  are  those  of 
the  first  growth)  have  been  known,  in  this 
soil,  to  yield  two  tons  and  a  half  of  sugar 
per  acre.  The  black  mould  of  several  va- 
rieties may  be  reckoned  after  this.  The 
best  is  the  deep  black  earth  of  Barbadoes, 
Antigua,  and  some  other  of  the  windward 
islands  ;  but  there  is  a  species  of  this 
mould  in  Jamaica,  that  is  perhaps  not  in 
the  least  inferior  to  it,  which  abounds 
with  limestone  and  flint,  on  a  substratum 
of  soapy  marie.  Black  mould  on  clay  is 
more  common  ;  and,  when  properly  pul- 
verized and  manured,  becomes  very  pro- 
ductive, and  may  be  said  to  be  inexhaus- 
tible. But  there  are  few  soils,  that  pro- 
duce a  greater  return  of  refined  sugar, 
than  a  peculiar  sort  of  land  on  the  north 
side  of  Jamaica,  and  particularly  in  the 
parish  of  Trelawney.  This  land  is  gene- 
rally of  a  red  colour,  is  every  where  re- 
markable when  first  turned  up  for  a  glossy 
surface,  and  when  wetted,  stains  the  fin- 
gers like  paint.  It  appears  to  consist  of  a 
native  earth  or  pure  loam,  with  a  mixture 
of  clay  and  sand;  and  though  deep,  it  is 
by  no  means  heavy,  and  is  naturally  dry. 
Hence,  as  its  fertility  is  destroyed  when 
too  much  exposed  to  the  burning  influence 
of  a  tropical  sun,  the  system  of  husban- 
dry, where  this  soil  abounds,  chiefly  de- 
pends on  what  is  called  ratoon  canes.  Ra- 
toons  are  the  suckers,  that  spring  from 
the  roots  or  stools  of  the  canes  that  have 
been  previously  cut  for  sugar,  and  are  ge- 
nerally ripe  in  twelve  months.  Plant- 
canes,  or  canes  of  the  first  growth,  are  the 
immediate  produce  of  the  original  germs 
placed  in  the  ground,  and  require  from  fif- 
teen to  seventeen  months  to  bring  them  to 
maturity.  The  first  yearly  returns  from 
their  roots  are  called  first  ratoons,  the  se- 
cond year's  growth  second  ratoons,  and 
so  on,  according  is  their  age.  The  com- 
mon yielding  too  of  this  cane-land,  on  an 
average,  is  seven  hogsheads  of  16  cwt.  to 
ten  acres,  which  are  cut  every  year. 

The  crop  time  in  the  sugar  islands  is 
'Jie  season  of  festivity,  both  to  man  and 


beast ;  for  so  agreeable  to  the  taste,  and 
so  nourishing  to  the  corporeal  frame,  is 
the  juice  of  the  cane,  that  every  animal 
derives  health  and  vigour  from  its  use. 
Such  of  the  negroes  as  were  meagre  and 
sickly  become  surprisingly  altered  for  the. 
better  in  a  few  weeks  after  the  mill  is  set 
in  action.  The  labouring  horses,  oxen, 
and  mules,  though  almost  constantly  at 
work  during  this  season,  yet,  in  conse- 
quence of  eating  plentifully  of  the  green 
tops  of  this  invigorating  plant,  and  being 
ing  indulged  with  some  of  the  scummings 
from  the  boiling-house,  improve  more 
than  at  any  other  period  of  the  year. 
Even  pigs  and  poultry  fatten  on  the  re- 
fuse. In  short,  during  crop-time,  plenty 
and  industrious  cheerfulness  every  where 
prevail  in  such  a  high  degree  on  a  well- 
regulated  plantation,  as  considerably  to 
soften  the  hardships  of  slavery,  and  induce 
an  impartial  spectator  to  conclude,  that 
the  miseries  of  life  are  sometimes  exag- 
gerated through  the  delusive  medium  of 
fancy. 

Such  planters,  as  are  not  fortunately 
furnished  with  the  means  of  grinding  their 
canes  by  water,  are  at  this  season  fre- 
quently impeded  by  the  failure  or  insuffi- 
ciency of  their  mills  ;  for  though  a  sugar- 
mill  is  a  very  simple  contrivance,  yet  great 
force  is  requisite  to  make  it  vanquish  the 
resistance  which  it  necessarily  meets  with, 
it  principally  consists  of  three  upright  iron 
rollers  or  cylinders,  from  thirty  to  forty 
inches  in  length,  and  from  twenty  to  twen- 
ty-five inches  in  diameter ;  and  the  middle 
one,  to  which  the  moving  power  is  ap- 
plied, turns  the  other  two  by  means  of 
cogs.  The  canes,  which  are  previously 
cut  short  and  tied  into  bundles,  are  twice 
compressed  between  these  rollers;  for, 
after  they  have  passed  through  the  first 
and  second  rollers,  they  are  turned  round 
the  middle  one  by  a  piece  of  frame  work 
of  a  circular  form,  which  is  called  in  Ja- 
maica the  dumb-returner,  and  forced  back 
through  the  second  and  third.  By  this 
operation  they  are  squeezed  completely 
dry,  and  sometimes  even  reduced  to  pow- 
der. The  cane-juice  is  received  in  a  lea- 
den bed,  and  thence  conveyed  into  a  ves- 
sel called  the  receiver.  The  refuse,  or 
macerated  rind  of  the  cane,  which  is  call- 
ed cane-trash,  serves  for  fuel  to  boil  the 
liquor. 

The  juice  from  the  mill  usually  contains 
eight  parts  of  pure  water,  one  part  of  su- 
gar, and  one  part  made  up  of  gross  oil, 
and  mucilage,  with  a  portion  of  essential 
oil.  The  proportions  are  taken  at  a  me- 
dium ;  for  some  juice  has  been  so  rich  as 
to  make  a  hogshead  of  sixteen  hundred 
weight  of  sugar  from  thirthen  hundred 


SUG 


SUG 


gallons,  and  some  is  so  watery  as  to  re- 
quire more  than  double  that  quantity. 
The  richer  the  juice  is,  the  less  it  abounds 
Avith  redundant  oil  and  gum  ;  so  that  very 
little  knowledge  of  the  contents  of  any 
other  quantity  can  be  obtained  by  the 
most  exact  analysis  of  any  one  quantity  of 
juice. 

The  following  matters  are,  likewise, 
usually  contained  in  cane-juice.  Some  of 
the  green  tops,  which  serve  to  tie  the 
cane  in  bundles,  are  often  ground  in,  and 
yield  a  raw  acid  juice  exceedingly  dis- 
posed to  ferment  and  render  the  whole 
liquor  sour.  Beside  these,  they  grind  in 
some  pieces  of  the  ligneous  part  of  the 
cane,  some  dirt,  and  lastly,  a  substance 
of  some  importance,  which  may  be  called 
the  crust  This  substance  is  a  thin  black 
coat  of  matter  that  surrounds  the  cane  be- 
tween the  joints,  beginning  at  each  joint, 
and  gradually  growing  thinner  the  farther 
from  the  joint  upwards,  till  the  upper  part 
between  the  joints  appears  entirely  free 
from  it  and  resumes  its  bright  yellow  co- 
lour. It  is  a  fine  black  powder,  that  mixes 
with  the  clammy  exsudations  from  the 
cane  ;  and  as  the  fairness  of  the  sugar  is 
one  symptom  of  its  goodness,  a  small 
quantity  of  this  crust  must  very  much 
prejudice  the  commodity. 

The  sugar  is  obtained  by  the  following 
process  :  The  juice  or  liquor  runs  from 
the  receiver  to  the  boiling-house,  along  a 
wooden  gutter  lined  with  lead.  In  the 
boiling-house,  it  is  received  into  one  of  the 
copper  pans  or  caldrons,  called  clarifiers. 
Of  these  there  are  generally  three ;  and 
their,  dimensions  are  determined  by  the 
power  of  supplying  them  with  liquor. 
There  a,  e  water-mills,  that  will  grind  with 
great  facility  sufficient  for  thirty  hogsheads 
of  sugar  in  a  week.  Methods  of  quick 
boiling  cannot  be  dispensed  with  on  plan- 
tations thus  fortunately  provided ;  for 


otherwise  the  cane  liquor  would  unavoid- 
ably become  tainted  before  it  could  be  ex- 
posed to  the  fire.  The  purest  cane-juice 
will  not  remain  twenty  minutes  in  the  re- 
ceiver without  fermenting.  Hence,  clari- 
fiers are  sometimes  seen  of  one  thousand 
gallons  each.  But  on  plantations  that 
during  crop-time  make  from  fifteen  to 
twenty  hogsheads  of  sugar  a  week,  three 
clarifiers  of  three  or  four  hundred  gallons 
each,  are  sufficient.  The  liquor,  when  cla- 
rified, may  be  drawn  oil  at  once,  with 
pans  of  this  size,  and  there  is  leisure  to 
cleanse  the  vessels  every  time  they  are 
used.  Each  clarifier  is  furnished  either 
with  a  syphon  or  cock  for  drawing  off  the 
liquor.  It  has  a  flat  bottom,  and  is  hung 
to  a  separate  fire,  each  chimney  having  an 
iron  slider,  which,  when  shut,  causes  the 
fire  to  be  extinguished  through  want  of 
air.* 

'As  soon  as  the  stream  from  the  receiv- 
er has  filled  the  clarifier  with  fresh  liquor, 
and  the  fire  is  lighted,  the  temper,  which 
is  generally  Bristol  white-»lime  in  powder, 
is  stirred  into  it.  This  is  done,  in  order 
to  neutralize  the  superabundant  acid,  and 
to  get  rid  of  which  is  the  great  difficulty 
in  sugar-making.  Alkali,  or  lime,  gene- 
rally effects  this ;  and  at  the  same  time 
part  of  it  is  said  to  become  the  basis  of 
the  sugar.  Mr.  Edwards  affirms,  that  it 
affects  both  the  smell  and  taste  of  the  su- 
gar. It  falls  to  the  bottom  of  the  pans  in 
a  black  insoluble  matter",  which  scorches 
the  bottom  of  the  vessels,  and  cannot 
without  difficulty  be  detached  from  them. 
But  in  order  that  less  of  the  lime  may  be 
precipitated  to  the  bottom,  little  more 
than  half  a  pint  of  Bristol  lime  should  be 
allowed  to  every  hundred  gallons  of  li- 
quor, and  Mr  Bousie's  method  of  dissolv- 
ing it  in  boiling  water  previous  to  mixing 
it  with  the  cane-juice  should  beadopted.j 
As  the  force  of  the  fire  increases,  and 


*  The  clarifiers  are  generally  placed  in  the  middle  or  at  one  end  of  the  boiling- 
house.  When  they  are  placed  at  one  end,  the  boiler  called  the  teache  is  placed  at 
the  other,  and  three  boilers  are  usually  ranged  between  them.  The  teache  com- 
monly holds  from  70  to  100  gallons,  and  the  boilers  between  the  clarifiers  and  teache 
diminish  in  size  from  the  first  to  the  last.  But  when  the  clarifiers  are  in  the  middle, 
there  is  generally  a  set  of  three  boilers  on  each  side,  which  in  effect  form  a  double 
building-house.    This  arrangement  is  very  necessary  on  large  estates. 

f  Mr.  Bousie,  to  whom,  for  his  improvements  in  the  art  of  sugar-boiling,  the  As- 
sembly  of  Jamaica  gave  1,000/.  in  a  paper  which  he  distributed  among  the  mem- 
bers, recommends  vegetable  alkali,  or  ashes  of  wood,  such  as  pimento  tree,  dumb 
cane,  fern  tree,  cashew,  or  logwood,  as  affording  a  better  temper  than  quick-lime. 
Afterward,  however,  he  was  convinced,  that  sugar  formed  on  the  basis  of  fixed  alka. 
line  salts  never  stands  the  sea,  unless  some  earth  is  united  to  the  salts.  Such  earth 
as  approaches  nearest  to  the  basis  of  alum,  Mr.  Edwards  thinks,  would  be  most  pro  - 
per ;  and  it  deserves  to  be  inquired  how  far  a  proper  mixture  of  vegetable  alkaline 
salts  and  lime  might  prove  a  better  temper  than  either  lime  or  alkaline  salts  alone. 
In  some  parts  of  Jamaica,  where  the  cane-liquor  was  exceedingly  rich,  Mr.  Bousie 
made  very  good  sugar  without  a  particle  of  temper. 


SUG 


sua 


the  liquor  grows  hot,  a  scum  is  thrown 
up,  which  is  formed  of  the  gummy  matter 
of  the  cane,  with  some  of  the  oil,  and  such 
impurities  as  the  mucilage  is  able  to  en- 
tangle. The  heat  is  now  suffered  to  in- 
crease gradually  till  it  nearly  rises  to  the 
heat  of  boiling  water.  The  liquor,  how- 
ever, must  by  no  means  be  suffered  to 
boil.  When  the  scum  begins  to  rise  into 
blisters,  which  break  into  while  froth,  and 
generally  appear  in  about  forty  minutes,  it 
is  known  to  be  sufficiently  heated.  Then 
the  damper  is  applied,  and  the  fire  extin- 
guished ;  and  if  circumstances  will  ad- 
mit, the  liquor  after  this  is  suffered  to  re- 
main a  full  hour  undisturbed  In  the  next 
place,  it  is  carefully  drawn  ofi",  either  by 
a  siphon,  which  draws  up  the  clear  fluid 
through  the  scum,  or  by  means  of  a  cock 
at  the  bottom.  In  either  case,  the  scum 
sinks  down  without  breaking  as  the  liquor 
flows ;  for  its  tenacity  prevents  any  ad- 
mixture. The  liquor  is  received  into  a 
gutter  or  channel,  which  conveys  it  to  the 
evaporating  boiler,  commonly  called  the 
grand  copper;  and  if  produced  at  first 
from  good  and  untainted  canes,  it  will 
then  appear  almost  transparent. 

In  the  grand  or  evaporating  copper, 
which  should  be  sufficiently  large  to  re- 
ceive the  net  contents  of  one  of  the  clari- 
fiers,  the  liquor  is  suffered  to  boil,  and  the 
scum,  as  it  rises,  is  continually  taken  off 
by  large  scummers,  till  the  liquor  becomes 
finer  and  somewhat  thicker.  This  opera- 
tion is  continued  till  the  subject  is  so  re- 
duced in  quantity,  that  it  may  be  contain- 
ed in  the  next  or  second  copper,  into 
which  it  is  then  ladled.  The  liquor  is  now 
almost  of  the  colour  of  Madeira  wine.  In 
the  second  copper  the  boiling  and  scum- 
ming are  continued ;  and  if  the  subject 
be  not  so  clean  as  is  expected,  lime-water 
is  thrown  into  it.  This  addition  not  only 
serves  to  give  more  temper,  but  likewise 
to  dilute  the  liquor,  which  sometimes 
thickens  too  fast  to  permit  the  feculencies 
to  rise  in  the  scum.    When  the  froth  in 


boiling  arises  in  large  bubbles,  and  is  not 
much  discoloured,  the  liquor  is  said  to 
have  a  favourable  appearance  in  the  se- 
cond copper.  When  in  consequence  ot 
such  scumming  and  evaporation  the  li- 
quor is  again  so  reduced,  that  it  may  be 
contained  in  the  third  copper,  it  is  ladled 
into  it,  and  so  on  to  the  last  copper,  which 
is  called  die  teache.  This  arrangement 
supposes  four  boilers  or  coppers,  beside 
the  three  clarifiers. 

In  the  teache  the  subject  undergoes  an- 
other evaporation,  till  it  is  supposed  boil- 
ed enough  to  be  removed  from  the  fire. 
This  operation  is  usually  called  striking. 
i.  e.  ladling  the  liquor,  which  is  now  ex- 
ceeding thick,  into  the  cooler. 

The  cooler,  of  which  there  are  general- 
ly six,  is  a  shallow  wooden  vessel,  about 
eleven  inches  deep,  seven  feet  in  length, 
and  from  five  to  six  feet  wide.  A  cooler 
of  this  size  holds  a  hogshead  of  sugar. 
Here  the  sugar  grains  ;  i.  e.  as  it  cools,  it 
runs  into  a  coarse  irregular  mass  of  im- 
perfect crystals,  separating  itself  from  the 
molasses.  From  the  cooler  it  is  taken  to 
the  curing-house,  where  the  molasses 
drains  from  it.* 

B  it  here  it  may  be  proper  to  notice  the 
rule  for  knowing  when  the  subject  is  fit 
I  to  be  ladled  from  the  teache  to  the  cool- 
I  er.  Many  of  the  negro  boilers,  from  long 
j  habit,  guess  accurately  by  the  eye  alone, 
judging  by  the  appearance  of  the  grain  on 
.  the  back  of  the  ladle ;  but  the  practice 
{  generally  adopted  is  to  judge  by  what  is 
|  called  the  touch,  i.  e.  taking  up  wiUi  the 
j  thumb  a  small  portion  of  hot  liquor  from 
i  the  ladle,  and,  as  the  heat  diminishes, 
j  drawing  with  the  forefinger  the  liquid  into 
|  a  thread.  This  thread  will  suddenly  break 
1  and  shrink  from  the  thumb  to  the  suspend- 
ed finger,  in  different  lengths,  according 
as  the  liquor  is  more  or  less  boiled.  A 
thread  of  a  quarter  of  an  inch  long  gene- 
rally determines  the  proper  boiling  height 
for  strong  muscovado  sugar  .j 
'    The  curing-house  is  a  large  airy  build- 


*  It  is  necessary  to  observe  in  this  place,  that,  in  order  to  obtain  a  large-grained 
sugar,  it  must  be  suffered  to  cool  slowly  and  gradually.  If  the  coolers  be  too  shal- 
low, the  grain  is  injured  in  a  surprising  manner. 

-j-  The  vessel  called  the  teache  probably  derived  its  name  from  this  practice  of  try- 
ing by  the  touch  (tactio).  Some  years  ago,  John  Proculus  Baker,  Esq.  barrister  at 
law,  recommended  to  the  public  a  method  more  scientific  and  certain,  in  a  treatise 
which  he  published  in  1775,  entitled,  An  Essay  on  the  Art  of  making  Muscovado 
Sugar.  It  is  as  follows :  "  Provide  a  small  thin  pane  of  clear  crown  glass,  set  in  a 
frame,  which  I  would  call  a  tryer ;  on  this  drop  two  or  three  drops  of  the  subject, 
one  on  the  other,  and  carry  your  tryer  out  of  the  boiling-house  into  the  air.  Observe 
your  subject,  and  more  particularly  whether  it  grain  freely,  and  whether  a  small 
edge  of  molasses  separate  at  the  bottom.  I  am  well  satisfied,  that  a  little  experience 
will  enable  you  to  judge  what  appearance  the  whole  skip  will  put  on  when  cold,  by 
this  specimen,  which  is  also  cold.  This  method  is  used  by  chemists,  to  try  evapo- 
rated solutions  of  all  other  salts :  it  may  seem  therefore  somewhat  strange,  it  has 
not  been  long  adopted  in  the  boiling-house." 


SUG 


SUG 


ing,  provided  with  a  capacious  molasses 
cistern,  the  sides  of  which  are  sloped  and 
lined  with  terras,  or  boards.  A  frame  ot 
massy  joist-work  without  boarding  is 
placed  over  this  cistern  ;  and  empty  hogs- 
heads without  headings  are  ranged  on  the 
joists  of  this  frame.  Eight  or  ten  holes 
are  bored  in  the  bottoms  of  these  hogs- 
heads, and  through  each  of  the  holes  the 
stalk  of  a  plantain  leaf  is  thrust  six  or 
eight  inches  below  the  joists,  and  long 
enough  to  stand  upright  above  the  top  of 
the  hogshead.  Into  these  hogsheads  the 
mass  from  the  cooler  is  put,  which  is  call- 
ed potting;  and  the  molasses  drains 
through  the  spongy  stalk,  and  drops  into 
the  cistern,  whence  it  is  occasionally  tak- 
en for  distillation.  In  the  space  of  three 
weeks,  the  sugar  becomes  tolerably  dry 
and  fair.  It  is  then  said  to  be  cured,  and 
the  process  is  finished. 

Sugar  thus  obtained  is  called  muscova- 
do, and  is  the  raw  material  whence  the 
sugar-bakers  chiefly  make  their  loaf  or 
refined  lump.  There  is  another  sort, 
which  was  formerly  much  used  for  do- 
mestic purposes,  and  was  generally  known 
by  the  name  of  Lisbon  sugar  In  the 
West-Indies  it  is  called  clayed  sugar ;  and 
the  process  of  making  it  is  as  follows  : 

A  quantity  of  sugar  from  the  cooler  is 
put  into  conical  pots  or  pans,  which  the 
French  call  formes,  with  the  points  down- 
ward, having  a  hole  about  half  an  inch  in 
diameter  at  the  bottom,  for  the  molasses 
lo  drain  through,  but  which  at  first  is  clos- 
t  d  with  a  plug.  As  soon  as  the  sugar  in 
these  pots  is  cool,  and  becomes  a  fixed 
body,  which  is  known  by  the  middle  of 
the  top  falling  in,  the  plug  is  taken  out, 
and  the  pot  placed  over  a  large  jar,  in- 
tended to  receive  the  sirup  or  molasses 
i  hat  drains  from  it.  In  this  state  it  is  left 
as  long  as  the  molasses  continues  to  drop, 
when  a  stratum  of  clay  is  spread  on  the 
sugar,  and  moistened  with  water.  This, 
imperceptibly  oozing  through  the  pores 
of  the  clay,  dilutes  the  molasses,  in  con- 
sequence of  which  more  of  it  comes  away 
than  from  sugar  cured  in  the  hogshead, 
and  the  sugar  of  course  becomes  so  much 
whiter  and  purer.  According  to  Sloane, 
the  process  was  first  discovered  in  Brasil, 
by  accident  "  A  hen,"  says  he,  "  hav- 
ing her  feet  dirty,  going  over  a  pot  of  su- 
gar, it  was  found  under  her  feet  to  be 
whiter  than  elsewhere."  The  reason  as- 
signed why  this  process  is  not  universally 
adopted  in  the  British  sugar-islands  is  this, 
that  the  water  which  dilutes  and  carries 
away  the  molasses,  dissolves  and  carries 
with  it  so  much  of  the  sugar,  that  the  dif- 
ference in  quality  does  not  pay  for  the  dif- 
ference in  quantity.    It  is  probable,  how- 


ever, that  the  French  planters  are  of  a  dif- 
ferent opinion  ;  for  upwards  of  four  hun- 
dred of  the  plantations  of  St.  Domingo 
have  the  necessary  apparatus  for  claying, 
and  actually  carry  on  the  system. 

A  valuable  and  simple  process  has  late- 
ly been  discovered  by  Edward  Howard, 
Esq.  F.  II  S.  for  refining  sugar,  which  pro- 
mises to  be  of  great  advantage.  The  fol- 
lowing is  an  outline  of  the  process,  but  a 
more  detailed  account  of  it  may  be  ex- 
pected to  be  published  by  that  gentleman 
himself: — *'  Take  brown  sugar,  sift  it 
through  a  coarse  sieve,  then  put  it  lightly 
into  a  conical  vessel  having  holes  at  the 
bottom  (like  a  coffee  machine).  Then  mix 
some  brown  sugar  with  white  syrup,  that 
is,  syrup  of  refined  sugar,  to  the  consis- 
tency of  batter  or  thick  cream,  and  pour 
it  gently  on  the  top  of  the  sugar  in  the 
vessel  till  the  surface  is  covered.  The 
syrup  will  soon  begin  to  percolate,  and 
leave  the  surface  in  a  state  which  will  al- 
low more  syrup  to  be  poured  upon  it, 
which  is  to  be  done  carefully.    The  trea- 
cle will  be  found  to  come  out  at  the  bot- 
tom, having  left  the  whole  mass  perfectly 
white.  The  first  droppings  are  to  be  kept 
apart,  as  the  last  will  serve  to  begin  ano- 
ther operation.    The  sugar  is  now  in  a 
pure  state,  except  as  to  its  containing  in- 
soluble matter,  which  may  of  course  be 
separated  by  solution  in  water. — The  cla- 
rification is  to  be  performed  by  the  best 
pipe-clay  and  fuller's  earth,  and  the  addi- 
tion of  neutral  alum,  if  lime  be  previous- 
ly contained  therein  ;  the  whole  to  be  agi- 
tated together  ;  and,  if  expedition  be  re- 
quired, it  should  be  heated  to  the  boiling 
point :  the  feculencies  will  then  subside. 
The  brown  syrup  may  also  be  much  im- 
proved by  means  of  tannin  and  the  above 
earths.    To  make  the  sugar  into  snow- 
white  powder,  it  is  only  necessary  to  eva- 
porate the  clarified  solution  to  dryness  on 
a  water-bath.    To  make  loaves,  the  com- 
mon methods  may  be  resorted  to,  or  the 
syrup  drawn  off  by  exhaustion,  or  small 
grains  may  be  made  according  to  M.  Du 
Trone's  process,  with  much  water;  and 
these  grains  may  be  cemented  by  hot  con- 
centrated syrup." 

Sugar  is  very  soluble  in  water,  and  is  a 
good  medium  for  uniting  that  fluid  with 
oily  matters.  It  is  much  used  for  domes- 
tic purposes,  and  appears  upon  the  whole 
to  be  a  valuable  and  wholesome  article  of 
food,  the  uses  of  which  are  most  proba- 
bly restricted  by  its  high  price.  This  price 
may  in  a  certain  degree  arise  from  the  na- 
ture of  the  article,  and  its  original  cost ; 
but  is  no  doubt  in  a  great  measure  owing 
to  the  inhuman  and  wasteful  culture  by 
slaves,  and  the  absurd  principles  of  Euro- 


SUG 


SUL 


pean  colonization,  duties,  draw-backs,  and 
bounties,  which  have  the  effect  to  create 
unnatural  monopolies,  and  to  prevent 
commerce  from  finding-  its  level.  This  is 
eminently  the  case  with  regard  to  the  Bri- 
tish West-India  islands,  and  their  pro- 
duce. 

One  very  extensive  use  of  sugar  and 
saccharine  juices  consists  in  the  forma- 
tion of  ardent  spirit,  an  article  which,  all 
things  considered,  is  perhaps  a  curse  to 
society.  The  wines  or  beers  of  pure  su- 
gar ferment  so  rapidly,  that  they  can 
scarcely  be  kept,  but  are  for  the  most 
part  made  for  immediate  use.  We  do  not 
know  of  any  beer  of  pure  sugar,  which  is 
stored  and  kept  for  sale  ;  though  it  is  said 
to  enter  largely  into  the  composition  of 
porter  ;  and  a  kind  of  beer  for  present  use 
is  made  by  fermenting  treacle  and  water 
in  many  country  places     See  Alcohol. 

Mr.  Haussman  says,  that  when  he  used 
nitric  acid  of  40°  to  convert  sugar  into 
oxalic  acid,  either  of  its  full  strength  or 
diluted  with  equal  pdrts  of  water,  he  con- 
stantly obtained  a  little  greasy  matter, 
when  he  conducted  the  process  in  the 
large  way  on  a  vapour  bath. 

On  treating  the  same  sugar  three  times 
successively  with  equal  portions  of  this 
acid,  either  concentrated  or  diluted,  the 
first  portion  occasions  a  brown  colour,  and 
produces  the  smell  of  burnt  sugar :  and 
when  the  action  of  the  nitric  acid  has 
ceased,  some  of  this  grease  is  perceived 
swimming  at  the  top ;  and  it  appears  to  be 
farther  increased  by  the  successive  addi- 
tion of  the  other  two  portions  of  acid, 
which  cause  the  brown  colour  and  smell 
of  burnt  sugar  to  disappear,  forming  a 
great  abundance  of  oxalic  acid,  and  a 
small  quantity  of  the  malic  and  citric 
acids.  He  adds,  that,  perhaps,  if  the 
gasses  were  collected,  we  should  find  a 
little  acetic  acid  also. 

To  satisfy  himself  whether  the  sugar 
gave  rise  to  the  formation  of  the  grease, 
he  examined  one  of  the  largest  sized  su- 
gar-loaves, which  he  commonly  used.  He 
divided  it  into  two  equal  portions,  the  first 
consisting  of  the  outer  part  of  the  loaf, 
the  second  of  the  inner.  Each  of  these 
portions  he  boiled  for  a  few  minutes  in 
three  times  its  weight  of  water.  No 
grease  swam  on  either  of  these  solutions 
of  sugar,  after  they  were  cold ;  but  as 
they  were  not  very  clear,  he  began  to  sus- 
pect, that,  the  syrup  for  common  sugar 
being  clarified  with  bullocks'  blood  by 
the  sugar-bakers,  the  gelatinous  part  of 
this  animal  substance  unites  in  some  mea- 
sure with  the  particles  of  sugar  by  a 
forced  and  confused  crystallization,  and 


when  acted  upon  by  nitric  acid  may  give 
rise  to  the  separation  of  grease.    He  was 
not  long  before  he  satisfied  himself,  that 
his  suspicion  was  just ;  for,  on  making 
oxalic  acid  with  some  fine  white  sugar- 
candy,  and  at  the  same  time  with  the  fin- 
est loaf-sugar  he  could  procure,  neither 
of  these  showed  any  signs  of  grease. 
SUGAR  OF  LEAD.    See  Lead. 
SUGAR  OF  MILK     See  Milk. 
SUGAR,  MAPLE.    See  Maple  Su- 
gar. 

SULPHUR,  or  brimstone,  is  a  well 
known,  hard,  brittle,  inflammable  sub- 
stance, of  an  opake  yellow  colour.  It  is 
found  more  or  less  pure  in  the  neighbour- 
hood of  volcanoes  ;  where  most  probably 
it  is  always  expelled  from  some  previous 
state  of  combination,  by  the  heat  of  sub- 
terraneous fires.  It  is  a  very  common  in- 
gredient, in  a  great  variety  of  minerals 
and  ores  ;  but  it  extracted  for  sale  chiefly, 
from  a  stone  called  pyrites. 

In  order  to  obtain  sulphur  from  pyrites, 
this  mineral  ought  to  be  exposed  to  a  heat 
sufficient  to  sublime  the  sulphur,  or  to 
make  it  distil  in  vessels,  which  must  be 
close  to  prevent  its  burning. 

Sulphur  is  extracted  from  pyrites,  at  a 
work  at  Schwartzemberg,  in  Saxony,  in 
the  high  country  of  the  mines,  and  in  Bo- 
hemia, at  a  place  called  Alten-Sattel. 

The  furnaces  employ*  d  for  this  opera- 
tion are  described  by  Macquer.  They  are 
oblong,  like  vaulted  galleries  ;  and  in  the 
vaulted  roofs,  are  made  several  openings. 
These  are  called  furnaces,  for  extracting 
sulphur. 

In  these  furnaces  are  placed  earthen- 
ware tubes,  filled  with  pyrites  broken  into 
pieces,  of  the  size  of  small  nuts.  Each  of 
these  tubes,  contains  about  fifty  pounds 
of  pyrites.  They  are  placed  in  the  fur- 
nace almost  horizontally,  and  have  scarce- 
ly  more  than  an  inch  of  descent.  The 
ends,  which  come  out  of  the  furnace  five 
or  six  inches,  become  gradually  narrower 
Within  each  tube,  is  fixed  a  piece  of  bak- 
ed earth,  in  form  of  a  star,  at  the  place 
where  it  begins  to  become  narrower,  in 
order  to  prevent  the  pyrites  from  falling 
out  or  choking  the  mouth  of  the  tube. — 
To  each  tube  is  fitted  a  receiver,  covered 
with  a  leaden  plate,  pierced  with  a  small 
hole  to  give  air  to  the  sulphur.  The  other 
end  of  the  tube,  is  exactly  closed.  A  mo- 
derate fire  is  made  with  wood,  and  in 
eight  hours  the  sulphur  of  the  pyrites, 
is  found  to  have  passed  into  the  receiv- 
ers. 

The  residuum  of  the  pyrites,  after  the 
distillation,  is  drawn  out  at  the  large  end, 
and  fresh  pyrites  is  put  in  its  place.  From 


SUL 


SUL 


Hus  residuum,  which  is  called  burnings 
of  sulphur,  sulphat  of  iron  is  extracted. 
See  Sulphuric*  Acid. 

The  eleven  tubes  into  which  are  put,  at 
three  several  distillations,  in  all  nine  quin- 
tals, or  900  lbs.  of  pyrites,  yield  from  100 
to  150  lbs.  of  crude  sulphur,  which  is  so 
impure,  as  to  require  purification  by  a  se- 
cond distillation. 

This  purification  of  crude  sulphur  is  also 
done  in  a  furnace,  in  form  of  a  gallery,  in 
which  five  iron  cucurbits  are  arranged  on 
each  side.  These  cucurbits  are  placed 
in  a  sloping  direction,  and  contain  about 
eight  quintals  and  a  half  of  crude  sulphur. 
To  them  are  luted  earthen  tubes,  so  dis- 
posed, as  to  answer  the  purpose  of  capi- 
tals. The  nose  of  each  of  these  tubes  is 
Inserted  into  an  earthen  pot,  called  the 
forerunner.  This  pot  has  three  openings ; 
namely,  that  which  receives  the  nose  of 
the  tube ;  a  second  smaller  hole,  which 
is  left  open  to  give  air ;  and  a  third  in  its 
lower  part,  which  is  stopped  with  a  wood- 
en peg. 

When  the  preparations  are  made,  afire 
is  lighted  about  seven  o'clock  in  the  even- 
ing, and  is  a  little  abated,  as  soon  as  the 
sulphur  begins  to  distil  At  three  o'clock 
in  the  morning,  the  wooden  pegs,  which 
stop  the  lower  holes  of  the  forerunners, 
are  for  the  first  time  drawn  out,  and  the 
sulphur  flows  out  of  each  of  them  into  an 
earthen  pot,  with  two  handles,  placed  be- 
low for  its  reception.  In  this  distillation 
the  fire  must  be  moderated,  and  prudent- 
ly conducted  ;  otherwise,  less  sulphur 
would  be  obtained,  and  it  would  also  be 
of  a  gray  colour,  and  not  of  a  fine  yellow, 
which  it  ought  to  have  when  pure.  The 
ordinary  loss  in  the  purification  of  eight 
quintals  of  crude  sulphur,  is,  at  most  one 
quintal. 

When  the  sulphur  is  all  flowed  out,  and 
has  cooled  a  little  in  the  earthen  pots,  it 
is  cast  into  moulds  made  of  beech-tree, 
which  had  been  previously  dipped  in  wa- 
ter, and  set  to  drain.  As  soon  as  the  sul- 
phur is  cooled  in  the  moulds,  they  are 
opened,  and  the  cylinders  ot  sulphur  are 
taken  out,  and  put  up  in  casks.  These 
are  called  roll-brimstone. 

As  sulphur  exists  not  only  in  pyrites, 
but  in  most  metallic  minerals,  it  is  evi- 
dent that  it  might  be  obtained  by  works 
in  the  large  way,  from  the  different  ores 
which  contain  much  of  it,  and  from  which 
it  must  be  separated,  previously  to  their 
fusion  :  but  as  sulphur  is.  of  little  value, 
the  trouble  of  collecting  it  from  ores  is 
seldom  taken.  Smeltefs  are  generally 
satisfied  with  freeing  their  ores  from  it,  by 
exposing  them  to  a  fire  sufficient  to  expel 
VOL.  II. 


it.    This  Operation  is  called  torrefaction, 

or  roasting  of  ores.    See  Ores. 

There  are,  however,  ores  which  contain 
so  much  sulphur,  that  part  of  it  is  actu- 
ally collected,  in  the  ordinary  operation  of 
roasting,  without  much  trouble  for  that 
purpose.  Such  is  the  ore  of  Ramelsberg, 
in  the  county  of  Hartz. 

This  ore,  which  is  of  lead  containing 
silver,  is  partly  very  pure,  and  partly  mix- 
ed with  cupreous  pyrites  and  sulphur ; 
hence  it  is  nr- pessary  to  roast  it. 

The  roasting  is  performed  by  laying  al- 
ternate strata  of  ore  and  wood,  upon  each 
other  in  an  open  field,  taking  care  to  di- 
minish the  size  of  ihe  strata  as  they  rise 
higher,  so  that  the  whole  mass  shall  be  a 
quadrangular  pyramid  truncated  above, 
the  base  of  which  is  about  thirty -one  feet 
square.  Below,  some  passages  are  left 
open,  to  give  free  entrance  to  the  air  ;  and 
the  sides  and  top  of  the  pyramid,  are  co- 
vered over  with  small  ore,  to  concentrate 
the  heat,  and  make  it  last  longer.  In  the 
centre  of  this  pyramid  there  is  a  channel, 
which  descends  vertically  from  the  top  to 
the  base.  When  all  is  properly  arranged, 
ladlefuls  of  red-hot  scoria  from  the  smelt- 
ing furnace,  are  thrown  down  the  chan- 
nel, by  which  means  the  shrubs  and  wood, 
placed  below  for  this  purpose,  are  kindled, 
and  the  fire  is  from  them,  communicated 
to  all  the  wo<5d  of  the  pile,  which  conti- 
nues burning  till  the  third  day.  At  that 
time  the  sulphur  of  the  mineral,  becomes 
capable  of  burning  spontaneously,  and  ot* 
continuing  the  fire,  after  the  wood  is  con- 
sumed. 

AVhen  this  roasting  has  been  continued 
fifteen  days,  the  mineral  becomes  greasy, 
that  is,  it  is  covered  over  with  a  kind  of 
varnish  :  twenty  or  twenty-five  holes  or 
hollows,  are  then  made  in  the  upper  part 
of  the  pile,  in  which  the  sulphur  is  col- 
lected. From  these  cavities  the  sulphur 
is  taken  out,  thrice  every  day,  and  thrown 
into  water.  This  sulphur  is  not  pure,  but 
crude,  and  is  therefore  sent  to  the  manu- 
facturers of  sulphur,  to  be  purified  in  the 
manner  above  related. 

As  this  ore  of  Ramelsberg  is  very  sul- 
phureous, the  first  roasting,  which  we 
are  now  describing,  lasts  three  months  ; 
and  during  this  time,  if  much  rain  have 
not  fallen,  or  if  the  operation  have  not 
failed  by  the  pile  falling  down  or  cracking, 
by  which  the  air  has  so  much  free  access, 
that  the  sulphur  is  burnt  and  consumed, 
from  ten  to  twenty  quintals  of  crude  sul- 
phur, are  by  this  method  collected. 

The  sulphur  of  this  ore,  like  that  of 
most  others,  was  formerly  neglected,  till 
in  the  vear  1570,  a  person  employed  in 
3  I 


SUL 


SUL, 


ihe  mines  called  Christopher  Sauder,  dis- 
'.  coveredrthe  method  of  collecting  it,  nearly 
as  it  is  done  at  present. 

Metallic  minerals  are  not  the  only  sub- 
stances,  from  which  sulphur  is  extracted  ; 
this  matter  is  diffused  in  the  earth  in  such 
quantities,  that  the  metals  cannot  absorb 
it  all.  Some  sulphur  is  found  quite  pure, 
and  in  different  forms,  principally  in  the 
neighbourhood  of  volcanoes,  in  caverns, 
and  in  mineral  waters.  Such  are  the  opake 
kind,  called  virgin  sulphur :  the  transpa- 
rent kind,  called  sulphur  of  Quito  ;  and 
the  native  flowers  of  sulphur,  as  those  of 
the  waters  of  Aix-la-Chapelle.  It  is  also 
found  mixed  with  different  earths.  Here 
we  may  observe,  that  all  those  kinds  of 
sulphur,  which  are  not  mineralized  by  me- 
tallic substances,  are  found  near  volca- 
noes, or  hot  mineral  waters,  and  conse- 
quently in  places,  where  nature  seems  to 
have  formed  great  subterranean  laborato- 
ries, in  which  sulphureous  minerals  may 
be  analysed  and  decomposed,  and  the  sul- 
phur separated,  in  the  manner  in  which 
it  is  done  in  the  small  way,  in  our  works 
and  laboratories.  However  this  may  be, 
certainly  one  of  thebestand  most  famous 
sulphur  mines  in  the  world,  is  that  called 
Solfatara. 

The  Abbe  Nollet  has  published,  in  the 
Memoirs  of  the  Academy,  some  interest- 
ing observations  upon  this  sutJjectjOf  which 
Macquer  gives  the  following  abridge- 
ment. 

Near  Puzzoli,  in  Italy,  is  that  great  and 
famous  mine  of  sulphur  and  alum,  called 
at  present  Snlfatara.  It  is  a  small  oval 
plain,  the  greatest  diameter  of  which  is 
about  400  yards,  raised  about  300  yards 
above  the  level  of  the  sea.  It  is  surround- 
ed by  high  lulls  and  great  rocks,  which 
fall  to  pieces,  and  the  fragments  of  which 
form  very  steep  banks.  Almost  all  the 
ground  is  bare  and  white,  like  marl ;  and 
is  every  where  sensibly  warmer  than  the 
atmosphere,  in  the  greatest  heat  of  sum- 
mer ;  so  that  the  feet  of  persons  walking 
there,  are  burnt  through  their  shoes.  It 
is  impossible  not  to  observe  the  sulphur 
there,  for  every  where  may  be  perceived 
by  the  smell,  a  sulphureous  vapour,  which 
rises  to  a  considerable  height,  and  gives 
reason  to  believe,  that  there  is  a  subterra- 
neous lire  below,  from  which  that  vapour 
proceeds. 

Near  the  middle  of  the  held,  there  is  a 
kind  of  basin,  three  or  four  feet  lower  than 
the  rest  of  the  plain,  in  which  a  sound 
may  be  perceived  when  a  person  walks  on 
it,  as  if  there  were  under  his  feet  some 
great  cavity,  the  roof  of  which  was  very 
thin.  After  that,  the  lake  Agnano  is  per- 
ceived, the  waters  of  which  seem  to  boil. 


These  waters  are  indeed  hot,  but  not  so 
hot  as  boiling  water.  This  kind  of  ebul- 
lition proceeds  from  vapours  rising  from 
the  bottom  of  the  lake,  which,  being  set 
in  motion  by  the  action  of  subterranean 
fires,  have  force  enough  to  raise  all  that 
mass  of  water.  Near  this  lake  there  are 
pits,  not  very  deep,  from  which  sulphure- 
ous vapours  are  exhaled.  Persons  who 
have  the  itch,  come  to  these  pits  and  re- 
ceive the  vapours,  in  order  to  be  cured. 
Finally,  there  are  some  deeper  excava- 
tions, whence  a  soft  stone  is  procured, 
which  yields  sulphur. 

From  these  cavities  vapours  exhale,  and 
issue  out  with  a  noise,  which  are  nothing 
else,  than  sulphur  subliming  through  the 
crevices.  This  sulphur  adheres  to  the 
sides  of  the  rocks,  where  it  forms  enor- 
mous masses :  in  calm  weather  the  va- 
pours may  be  evidently  seen  to  rise  twenty- 
five  or  thirty  feet,  from  the  surface  of  the 
earth. 

The  vapours,  attaching  themselves  to 
the  side  of  rocks,  form  enormous  groups 
of  sulphur,  which  sometimes  fall  down  by 
their  own  weight,  and  render  these  places 
of  dangerous  access. 

In  entering  the  Solfatara,  there  are 
warehouses  and  buildings  erected  for  the 
refining  of  sulphur. 

Under  a  great  shed,  supported  by  a 
wall  behind,  open  on  the  other  three  sides, 
sulphur  is  procured  by  distillation,  from 
the  soft  stones  we  mentioned  above. — 
These  stones  are  dug  from  under  ground ; 
and  those  which  lie  on  the  surface  of  the 
earth  are  neglected.  These  last  are,  how- 
ever, covered  with  a  sulphur  ready  form- 
ed, and  of  a  yellow  colour ;  but  the  work- 
men say  they  have  lost  their  strength,  and 
that  the  sulphur  obtained  from  them  is 
not  of  so  good  a  quality  as  the  sulphur 
obtained,  from  the  stones  which  are  dug 
out  of  the  ground. 

These  last-mentioned  stones  are  broken 
into  lumps,  and  put  into  pots  of  earthen, 
ware,containing  each  about  twenty  quarts. 
The  mouths  of  these  pots  are  as  wide  as 
their  bottoms ;  but  their  bellies,  or  middle 
parts,  are  wider.  They  are  covered  with 
a  lid  of  the  same  earth,  well  luted,  and 
are  arranged  in  two  parallel  lines,  along 
two  brick  walls,  which  form  the  two  sides 
of  a  furnace.  The  pots  are  placed  within 
these  walls ;  so  that  the  centre  of  each 
pot,  is  in  the  centre  of  the  thickness  of 
the  wall,  and  one  end  of  the  pots,  over- 
hangs the  wall  within,  while  the  other 
end  overhangs  the  wall  without.  In  each 
furnace  ten  of  these  pots  are  placed  ;  that 
is,  five  in  each  of  the  two  walls,  which 
form  the  two  sides  of  the  furnace.  Be- 
twixt these  walls  there  is  15  or  18  inches  ; 


SUL 


SUL 


wliich  space  is  covered  by  a  vault>  resting 
on  the  two  walls.  The  whole  forms  a 
furnace  seven  feet  long,  two  feet  and  an 
half  high,  open  at  one  end,  and  shut  at 
the  other,  excepting-  a  small  chimney, 
through  which  the  smoke  passes. 

Each  of  these  pots  has  a  mouth  in  its 
upper  part  without  the  furnace,  in  order 
to  admit  a  tube  of  18  lines  in  diameter, 
and  a  foot  in  length,  which  communicates 
with  another  pot  of  the  same  size  placed 
without  the  building,  and  pierced  with  a 
round  hole  in  its  base,  of  15  or  18  lines 
diameter.  Lastly,  to  each  of  these  last- 
mentioned  pots,  there  is  a  wooden  tub 
placed  below,  on  a  bench  made  for  this 
purpose. 

Four  or  five  of  these  furnaces  are  built 
under  one  shed.  Fires  are  kindled  in  each 
of  them  at  the  same  time  ;  and  they  are 
thrown  down  after  each  distillation,  ci- 
ther that  the  pots  may  be  renewed,  or  thai, 
the  residuum  may  be  more  easily  taken 
out. 

The  tire,  being  kindled  in  the  furnace, 
heats  the  iirst  pots,  containing  the  sul- 
phureous stones.  The  sulphur  rises  in 
fumes  into  the  upper  part  of  the  pot, 
whence  it  passes  through  the  pipe  of  com- 
munication, into  the  external  vessel. — 
There  the  vapours  are  condensed,  become 
liquid,  and  How  through  the  hole  below 
into  the  tub,  from  which  the  sulphur  is 
easily  turned  out,  because  the  form  of  the 
vessel,  is  that  of  a  truncated  cone,  the 
narrower  end  of  which  is  placed  below ; 
and  because  the  hoops  of  the  tub  are  so 
fastened,  that  they  may  be  occasionally 
loosened.  The  mass  of  sulphur  is  then 
carried  to  the  buildings  mentioned  before, 
where  it  is  remelted  for  its  purification, 
and  cast  into  rolls,  as  we  receive  it. 

For  accurate  purposes,  sublimation  is 
necessary,  to  deprive  sulphur  of  the  ac- 
cidental impurities  it  may  contain.  This 
may  be  done  in  an  earthen  cucurbit  set 
on  a  sand-bath,  with  a  head  properh  adap- 
ted. The  sulphur  rises  by  a  very  gen- 
tle heat,  little  more  than  is  sufficient  to 
melt  it ;  and  the  fine  sublimate  thus  ob- 
tained, is  called  flowers  of  brimstone,  or 
of  sulphur. 

Water  has  no  immediate  action  on  sul- 
phur. 

Sulphur  is  soluble  in  alcohol. 

Sulphuric  ether  by  long  digestion,  takes 
up  about  one-thirteenth  of  its  weight  in 
the  light,  and  only  a  seventeenth  in  the 
dark. 

The  combinations  of  sulphur  with  earths 
or  alkalies,  were  formerly  called  hepars, 
or  livers  of  sulphur,  from  their  colour  ;  a 
name  which  has  been  changed  for  that  of 
sulphurets.   There  is  no  perceptible  ac- 


tion between  sulphur  and  silex.  Alunyjie. 
has  very  little  action  upon  it,  in  the*riTreflfc* 

way ;  but  lime  unites  readily  with  it.  If 
fresh,  quicklime  and  flowers  of  sulphur 
be  mixed,  and  water  be  added  a  little  at 
a  time,  the  heat  of  the  lime  will  be  suffi- 
cient to  produce  the  combination.  On  ad- 
dition of  more  water,  it  becomes  reddish, 
and  emits  a  foetid  smell,  of  rotten  eggs, 
which  is  common  to  all  the  sulphurets. 
The  more  caustic  the  lime,  the  deeper  the 
colour  of  the  sulphuret.  The  pure  fixed 
alkalies,  decompose  sulphuret  of  lime,  by 
virtue  of  their  stronger  affinity  to  the  sul- 
phur ;  and  any  acid  whatever  decomposes 
it,  by  attracting  the  lime,  the  sulphur  at 
the  same  time  falling  to  the  bottom  in  the 
form  of  a  subtile  white  powder,  formerly 
called  magistery  of  sulphur. 

Pure  barites  boiled  in  water  with  sul- 
phur has  but  little  action  upon  it. 

If  a  small  quantity  of  magnesia,  and  an 
equal  quantity  of  flowers  of  sulphur,  be 
enclosed  in  a  vessel,  perfectly  filled  up 
with  distilled  water,  and  well  stopped, 
and  then  exposed  to  heat  by  immersion, 
in  boiling  water  for  several  hours,  a  com- 
bination will  take  place ;  and  the  water 
will  contain  a  sulphuret  of  magnesia. 

The  fixed  alkalies  combine  very  readily 
with  sulphur,  either  in  the  moist  or  dry 
way,  whether  they  be  in  a  caustic  state, 
or  combined  with  carbonic  acid ;  though 
more  strongly,  in  the  former  than  the 
latter  case.  If  a  solution  of  fixed  alkali 
in  water,  be  boiled  with  half  its  weight  of 
powdered  sulphur,  a  combination  takes 
place,  and  a  sulphuret  is  formed.  Or  if 
equal  parts  of  dry  alkali,  and  powdered 
sulphur,  be  melted  in  a  crucible,  and 
poured  out  on  a  flat  polished  stone,  as 
soon  as  the  fusion  is  complete,  the  com- 
bination will  be  of  a  liver  colour,  and  is 
the  solid  sulphuret.  If  it  be  made  with 
a  caustic  alkali,  its  colour  is  deeper,  and 
its  characteristic  properties  more  intense, 
than  when  a  mild  alkali  is  used.  A  so- 
lution of  the  solid  sulphuret  in  water, 
forms  precisely  the  same  substance  as  the 
preparation  made  in  the  moist  way. 

All  the  sulphurets  are  decomposable  by- 
acids,  which  precipitate  the  sulphur  in  a 
w  hite  powder,  formerly  called  milk  of  sul- 
phur. This,  according  to  Dr.  Thomson,  is 
a  compound  of  sulphur  and  water,  which 
may  be  rendered  yellow  like  the  sublimed 
sulphur,  by  expelling  its  water  by  means 
of  heat. 

The  modes  of  separating  the  sulphur 
from  the  native  sulphurets  of  different 
metals,  have  already  been  given,  either 
under  the  metals  themselves,  or  the  arti- 
cle Ores  ;  but  as  the  subject  is  of  consi- 
derable importance,  and  has  been  scienti 


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fically  handled  in  the  Journal  des  Mines, 
by  Mr.  Gueniveau,  engineer  of  mines,  we 
shall  avail  ourselves  of  this  opportunity, 
of  introducing  his  observations. 

Among-  the  great  number  of  metallic 
sulphurets,  with  which  nature  presents  us, 
the  decomposition  of  many  is  of  much 
importance  in  the  arts.  The  sulphurets 
of  iron,  copper,  lead,  and  mercury,  and 
some  others,  give  rise  to  metallurgical 
processes,  that  particularly  claim  the  at- 
tention-of  those  who  are  addicted  to  the 
study  of  chemistry.  The  nature  and  pro- 
perties of  these  have  been  well  known, 
since  chemistry  has  made  them  an  object 
of  her  labours  :  but  as  the  facts  collected 
in  laboratories  have  never  been  caefully 
compared  with  those  that  extensive  works 
furnish,  though  we  are  well  aware,  that 
this  would  be  the  best  way  of  attaining 
useful  results,  the  theory  of  the  various 
operations  to  which  sulphurets  are  sub- 
jected has  not  yet  been  improved  by  the 
progress  of  that  science. 

The  action  of  heat  on  metallic  sulphu- 
rets requires  first  to  be  examined,  be- 
cause it  occurs  in  all  the  processes  em- 
ployed for  their  decomposition. 

The  sulphurets  of  mercury  and  arsenic 
are  volatilized  in  close  vessels,  when  ex- 
posed to  a  temperature  a  little  elevated. 

The  native  sulphuret  of  iron  experi- 
ences but  a  partial  decomposition  by 
means  of  caloric.  By  distillation  in  a  re- 
tort, we  cannot  extract  half  the  sulphur 
it  contains.  In  Saxony,  the  distillation  of 
pyrites  in  the  large  way  never  yields  more 
than  13  or  14  per  cent,  of  their  weight  of 
sulphur. 

On  sulphuretted  copper,  and  pyritous 
copper,  heat  produces  effects  analagous 
to  those  observed  with  iron.  The  distilla- 
tion of  pyritous  copper  afforded  me  but 
very  little  sulphur.  These  two  ores,  how- 
ever, may  be  considered  as  mixtures  of 
the  sulphurets  of  copper  and  of  iron,  and 
the  sulphur  separated  by  heat  comes  from 
that  of  iron  almost  wholly. 

The  sulphuret  of  lead,  or  galena,  is  one 
of  those  minerals,  the  treatment  of  which 
is  most  varied.  All  chemists  agree  in 
considering  it  as  a  compound  of  sulphur 
and  lead  only,  in  the  proportion  of  15 
parts  sulphur  to  85  of  lead. 

That  metallurgical  process,  the  object 
of  which  is  the  desulphuration  of  metals, 
is  known  by  the  name  of  roasting.  Most 
authors,  who  have  treated  of  it,  seem  to 
consider  caloric  as  the  sole  agent  in  the 
decomposition ;  and  even  those  who  have 
remarked  the  influence  of  the  air,  since 
the  establishment  of  the  new  chemical 
theory,  have  not  considered  it  as  essen- 
.  tial.   The  affinities  both  of  sulphur  and 


metallic  substances  for  this  principle  sen- 
der it  very  probable ;  and  it  is  likewise 
proved  by  the  chemical  examination  of 
the  products  of  all  roastings,  as  well  as 
by  the  manner  in  which  the  process  is 
conducted.  In  the  roasting  of  sulphurets,- 
instead  of  seeing  the  volatilization  of  the 
sulphur  effected  by  a  moderate  and  long- 
continued  heat,  we  find  a  sulphuret  de- 
composed by  the  simultaneous  action  of 
caloric  and  air :  and  the  acknowledged 
necessity  of  not  fusing  the  ore,  instead  of 
arising  from  the  fear  of  communicating 
to  it  by  liquefaction  a  cohesive  force  ca- 
pable of  resisting  the  separation  of  the 
sulphur,  will  be  ascribed  more  simply  to 
this  circumstance,  that  such  a  state  will 
confine  the  action  of  the  air  to  a  surface 
that  cannot  be  renewed,  and  will  soon  be 
covered  with  a  metallic  oxide. 

Roasting  of  Copper  Pyrites. 
Pieces  of  pyritous  copper  are  laid  on 
billets  of  wood  in  the  most  convenient 
manner  for  the  combustion  to  continue  a 
long  time.  The  first  heat  separates  part 
of  the  sulphur,  which  is  in  some  degree 
sublimed,  and  may  be  collected;  but  af- 
terward it  becomes  the  combustible,  that 
serves  by  burning  to  continue  the  opera- 
tion. 

Iron  pyrites  subjected  to  the  same  ope- 
ration will  undergo  similar  decomposi- 
tions in  the  same  order. 

It  remains  for  us  to  speak  of  a  furnace, 
in  which  both  the  smelting  and  roasting 
of  the  pyritous  copper,  to  a  certain  point, 
are  effected  at  the  same  time.  It  is  used 
at  Fahlun,  in  Sweden.  This  has  an  inte- 
rior crucible,  which  receives  the  product 
of  a  smelting  of  24  or  48  hours,  and  in 
which  a  separation,  or  rather  combustion, 
of  the  sulphur  is  effected.  A  stream  of 
air  from  the  bellows  is  made  to  blow  on 
the  melted  mass  with  such  force,  as  to 
drive  off  the  scoriae,  and  burn  a  part  of 
the  sulphur  that  is  found  on  the  surface. 
The  iron  is  thus  oxided,  and  quartz  is 
added  to  vitrify  it  in  proportion  as  the 
roasting  goes  on.  This  process  is  perhaps 
the  only  one,  in  which  sulphur  and  iron 
are  separated  in  so  large  a  quantity  at  the 
same  time. 

The  desulphuration  of  pyritous  copper 
by  roasting  appears  to  be  effected,  1st, 
By  the  sublimation  of  a  small  portion  of 
sulphur,  which  may  either  be  collected, 
or  burned  in  the  air  :  2dly,  By  the  disen- 
gagement of  sulphurous  acid,  which  is 
the  more  abundant  in  proportion  as  the 
process  is  well  managed :  3dly,  By  the 
vaporization  of  a  little  sulphuric  acid,  the 
greater  part  of  which,  however,  remains 
united  with  the  copper. 


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Roasting  of  Galena. 

Galena  is  very  difficult  to  desulphurate 
c  ompletely  by  roasting.  The  affinity  of 
its  component  parts  for  oxigen,  it  is  true, 
render  their  separation  sufficiently  spee- 
dy ;  but  that  of  the  new  compounds,  sul- 
phuric acid  and  oxide  of  lead,  gives  rise 
to  a  new  combination,  which  retains  the 
sulphur,  and  thus  forms  an  obstacle  to 
the  desulphuration.  To  this  affinity  of 
the  oxide  of  lead  for  sulphuric  acid  must 
be  ascribed  the  facility  with  which  this 
acid  is  formed  in  the  roasting  of  galena. 

In  roastings  in  the  large  way,  on  hearths 
prepared  for  the  purpose,  the  proportion 
of  sulphat  of  lead  is  still  more  considera- 
ble, being  in  the  ratio  of  the  temperature, 
and  the  facility  with  which  the  air  per- 
vades the  ore. 

The  reverberatory  furnace  is  employed 
with  great  success  to  roast  ores  of  sulphu- 
retted lead.  In  some  works,  indeed,  as 
at  Poullaouen,  such  a  complete  separation 
of  the  sulphur  is  accomplished  in  this 
furnace,  that,  when  the  roasting  is  judged 
to  be  finished,  nothing  more  than  the  ad- 
dition of  charcoal  is  requisite,  to  obtain 
directly  a  large  quantity  of  metallic  lead. 

The  same  furnace  is  employed  with 
success  at  Pezey  for  fusing  roasted  gale- 
na, containing  at  least  one  third  of  its 
weight  of  sulphat  of  lead.  Its  final  result 
gives  no  matts ;  which  proves,  that  it  per- 
mits the  decomposition  of  the  sulphat, 
and  the  separation  of  the  sulphur  it  con- 
tains. 

Some  furnaces  have  been  mentioned,  as 
that  of  Fahlun,  and  the  Scotch,  in  which 
^metallic  sulphurets  undergo  a  real  roast 
ing ;  but  there  are  others  in  which  this  ef- 
fect is  scarcely  sensible.  Some  reflections 
on  their  differences  in  this  respect  will 
probably  not  be  out  of  place  here ;  and 
they  will  be  the  more  interesting,  as  they 
are  intimately  connected  with  our  subject, 
and  account  for  phenomena,  which  are 
inexplicable  according  to  the  idea  gene- 
rally entertained  of  roasting. 

It  is  a  fact  well  known  in  smelting- 
houses,  that  the  highest  furnaces  are  least 
favourable  to  desulphuration,  or,  in  the 
language  of  metallurgists,  produce  the 
most  matts.  If  an  indisputable  proof  of 
this  were  required,  we  need  only  say,  that 
at  Pezey  we  have  seen  roasted  lead  ores 
containing  a  great  deal  of  sulphat  of  lead, 
which  smelted  in  the  Scotch  furnace 
yielded  not  matts  as  the  ultimate  result, 
"but  produced  a  large  quantity  in  the 
fourncau  a  manche  (a  kind  of  high  fur- 
nace). 

Desulphuration  of  Mercury. 
The  sulphuret  of  mercury  is  easily  de- 


composed. It  is  sufficient  to  present  lo 
the  sulphur  a  substance  capable  of  re- 
taining it,  and  the  mercury  may  be  volatil- 
ized alone.  Thus  iron  and  lime  are  em- 
ployed singly  or  conjointly  in  the  treat- 
ment of  cinnabarine  ores. 

Desulphuration  of  Copper. 

Copper  pyrites  are  smelted  in  some 
works  with  lime,  either  in  the  fourneau  a 
manchey  or  the  reverberatory  furnace ; 
but  this  process  is  not  sufficiently  known 
in  detail,  to  enable  us  to  judge  of  the  ef- 
ficacy of  this  agent. 

1st  Exp.  I  mixed  10  gram.  (155  grs.) 
of  pyrittms  copper,  the  composition  of 
which  I  knew,  with  4.3  gram.  (66  grs.)  of 
iron  filings ;  put  the  mixture  into  a  cru- 
cible ;  covered  it  with  charcoal  powder; 
and  heated  it  in  a  forge  fire  three  quarters 
of  an  hour.  The  proportion  of  iron  was 
calculated  so  as  to  be  sufficient  for  taking 
up  all  the  sulphur  combined  with  the  cop- 
per in  the  ore  employed.  In  the  crucible 
I  found  a  perfectly  homogeneous  mass, 
weighing  13.1  gram.  (202  grs  )  which  did 
not  contain  the  least  globule  of  metallic 
copper,  or  any  sign  of  separation  be- 
tween the  sulphuret  of  iron  and  that  of 
copper. 

2d  Exp.  Another  trial  was  made  with 
10  gram.  (155  grs.)  of  pyritous  copper 
and  5  gram.  (77  grs.)  of  the  same  mine- 
ral roasted,  which  is  nearly  the  state  of 
the  product  When  the  ore  or  matts  have 
not  been  completely  desulphurated.  The 
proportion  of  iron  was  still  insufficient  to 
separate  any  copper,  of  which  there  was 
abundance  in  the  mixture.  I  heated  it 
three  quarters  of  an  hour,  and  found,  as 
in  the  preceding  experiment,  a  homoge- 
neous mass,  without  any  sign  of  metallic 
copper,  or  pure  sulphuret  of  copper :  it 
was  a  true  copper  matt. 

3d  Exp.  Equal  parts  of  crude  and 
roasted  copper  pyrites  were  mixed,  mois- 
tened with  olive  oil,  and  heated  strongly 
for  half  an  hour  in  a  crucible  lined  with 
charcoal.  The  product  was  nothing  but 
a  powder,  that  had  not  undergone  any  fu- 
sion, no  doubt  owing  to  the  superabun- 
dance of  iron. 

The  desulphuration  of  copper  by  means 
of  iron  will  always  be  very  difficult  to  ef- 
fect, because  a  triple  compound  of  sul- 
phur, iron,  and  copper,  is  formed,  or  a 
combination  takes  place  between  the  sul- 
phurets of  copper  and  iron,  which  ob- 
structs the  separation  of  the  copper. 

Desulphuration  of  Galena. 
Galena  is  one  of  those  sulphurets  in 
which  this  decomposition  is  most  readily 
effected.    The  fusibility  of  lead,  which 


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facilitates  the  union  of  its  particles,  as 
well  as  the  little  affinity  it  has  for  sulphur, 
are  the  causes  of  the  success  of  the  at- 
tempts  of  this  kind.  Lime  and  iron  are 
employed  in  different  circumstances  for 
the  desulphuration  of  galena.  The  use 
of  lime  is  not  very  general,  and  it  is  im- 
possible to  judge  of  its  effects  from  what 
is  known  of  the  properties  of  sulphuret 
of  lime.  The  treatment  of  galena  by 
malleable  or  cast  iron  in  small  pieces  is 
more  in  use,  and  appears  very  advanta- 
geous. 

At  the  School  of  Mines  of  Montblanc 
a  great  many  experiments  have  been 
made  on  the  desulphuration  of  galena  by 
iron,  the  results  of  which  were  of  suffi- 
cient importance  to  render  the  publica- 
tion of  them  desirable. 

Dr.  Watson  has  shewn,  in  a  paper  on 
lead  ore,  in  the  Philosophical  Transac- 
tions, that  no  less  than  seven  hundred 
tons  are  annually  dissipated  in  the  various 
lead  mines  of  England,  for  want  of  a  dif- 
ferent mode  of  purifying  the  ores. 

The  sulphur  that  is  procured  in  the 
roasting  of  ores,  especially  those  of  cop- 
per, is  apt  to  contain,  besides  earthy  im- 
purities, a.very  notable  proportion  of  arse- 
nic, while  on  the  other  hand  the  volcanic 
sulphur  in  general,  and  that  of  Sicily  in 
particular,  is  entirely  free  from  this  con- 
tamination.   This  is  the  cause  of  the  uni- 
versal preference  given  by  the  manufac- 
turers of  sulphuric  acid  to  Sicilian,  over 
English  sulphur;  and  hence  it  is  a  mat- 
ter of  some  consequence  to  be  able  to 
ascertain  in  a  compendious  and  satisfacto- 
ry manner  the  purity  of  any  particular 
sample  of  this  substance.    The  following 
method  will,  we  believe,  be  found  to  an- 
swer every  practical  purpose.    Having  I 
rubbed  to  fine  powder  in  an  earthen-ware  ■ 
mortar  some  of  the  sulphur  to  be  exa-  j 
mined,  take  100  grs.  and  put  it  into  a  Flo- 1 
rence  flask  with  5  oz.  measures  of  the  j 
best  oil  of  turpentine ;  heat  the  mixture  \ 
gently  over  a  lamp,  or  a  pan  of  charcoal,  j 
till  it  has  boiled  for  about  a  minute,  then  1 
pour  the  clear  hot  solution  into  a  six  or  j 
eight-ounce  vial,  stop  it  with  a  cork,  and 
shake  it  till  the  liquor  has  cooled  down  to 
the  temperature  of  the  hand  ;  it  will  now 
be  quite  turbid  with  sulphur  that  has  se- 
parated  from  the  oil  during  its  cooling, 
and  being  run  through  a  glass  funnel  ve-  i 
ry  lightly  plugged  with  fine  tow  will  pass 
out  clear,  leaving  the  sulphur  behind. , 
The  oil  is  now  to  be  again  transferred  to 
the  sulphur  remaining  in  the  flask,  and  to  j 
be  a  second  time  boiled,  cooled,  and  filter- ! 
cd  as  before.    By  repeating  this  process 
four  or  five  times,  there  will  be  left  only 


a  brownish  orange  residue,  on  which  the 
oil  will  refuse  to  act  any  longer.  -This  re- 
sidue, being  laid  on  a  piece  of  earthen 
ware,  is  to  be  exposed  to  a  heat  not  high- 
er than  that  of  melting  lead,  till  it  ceases 
to  exhale  any  sulphureous  vapours ;  be- 
ing then  rubbed  up  with  a  little  moisten- 
ed charcoal,  and  pressed  into  the  bowl  of 
a  tobacco-pipe  or  Any  other  convenient 
vessel,  it  is  to  be  heated  nearly  red,  upon 
which  a  white  vapour  will  arise,  and  show 
itself  to  be  arsenic  by  its  peculiar  garlic 
odour.  The  sulphur  precipitated  from 
the  oil  of  turpentine  may  be  entirely  freed 
from  this  latter  by  exposure  to  the  air  and 
light  for  a  day  or  two  ;  it  will  then  be  of 
a  beautiful  sparkling  colour  (far  superior 
to  that  of  the  common  flowers  of  sulphur) 
and  entirely  inodorous.  The  common 
brimstone  or  roll  sulphur  sometimes  con- 
tains a  full  1-J.5th  of  insoluble  residue, 
chiefly  orpiment;  the  best  Sicilian  sul- 
phur in  small  rolls,  contains  hardly  more 
than  3  per  cent,  of  residue,  which  appears 
to  be  little  else  than  earth,  as  it  affords  no 
arsenical  odour  when  heated  with  char- 
coal. 

To  the  taste  sulphur  is  perfectly  insi- 
pid, when  broken  down,  however,  by  the 
teeth,  it  manifests  a  peculiar  indescriba- 
ble grittiness,  which  sufficiently  distin- 
guishes it  from  all  other  bodies.  It  is  in- 
odorous at  the  common  temperature,  but 
when  rubbed,  a  slight  fetid  smell  is  suffi- 
ciently perceivable ;  if  a  roll  of  sulphur 
is  held  for  a  minute  in  a  moist  warm 
hand,  it  breaks  across  with  a  sharp  crack- 
ling not  unlike  the  snapping  from  the  dis- 
charge of  an  electrical  spark,  the  hanil 
at  the  same  time  contracts  a  peculiar  dis- 
agreeable odour,  which  lasts  some  mi-  * 
nutes.  When  exposed  to  a  temperature 
of  about  224°  Fahr.  it  melts  into  a  trans- 
parent brownish  red  fluid ;  by  an  increase 
of  heat,  the  fluidity  diminishes,  and  the 
sulphur  begins  to  sublime  in  visible  va- 
pours ;  when  it  somewhat  exceeds  the 
temperature  of  300°  Fahr.  its  consistence 
will  be  viscid  and  thick  like  treacle,  and 
the  vapour  will  take  fire,  the  inflamma- 
tion instantly  spreading  to  the  rest  of  the 
mass. 

Oil  of  turpentine  and  the  other  essen- 
tial oils  dissolve  a  considerable  proportion 
of  sulphur  when  hot,  the  greatest  part  of 
which  they  again  deposit  in  crystals,  if 
cooled  slowly.  The  fat  oils  unite  with 
sulphur  by  ' boiling,  and  acquire  a  deep 
yellowish  brown  colour,  and  a  strong  fe- 
tid odour ;  the  combination  is  generally 
called  balsam  of  sulphur.  By  long  repose 
in  a  cool  place,  it  deposits  small  octoe- 
dral  crystals  of  sulphur. 


♦ 


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For  the  chemical  properties  of  sulphur, 
not  here  enumerated,  we  refer  the  reader 
to  elementary  treatises  on  chemistry. 

The  uses  of  sulphur  are  very  impor- 
tant. It  is  employed  in  medicine  ;  it  en- 
ters into  the  composition  of  sulphuric 
acid,  of  gunpowder,  and  of  the  common 
composition  for  paying  the  bottoms  of 
ships.  Its  fumes,  whert  burning,  are  em- 
ployed for  bleaching  silk  and  wool,  and 
checking  the  progress  of  vinous  fermen- 
tation. Common  matches  which  are  in 
daily  use  for  lighting  fires,  derive  their 
principal  utility  from  being  tipped  with 
sulphur. 

SULPHURET,  SULPHURETTED  HY- 
DROGEN, HYDROSULPHURETS,  &c- 
The  various  combinations  of  sulphur  with 
alkaline,  earthy,  and  metallic  bases,  of 
sulphur  with  hydrogen,  and  the  latter 
compound  with  the  several  bases  in  dif- 
ferent proportions  of  sulphuration,  are  so 
intimately  connected,  that  we  give  the 
whole  under  one  article. 

The  several  combinations  which  belong 
to  this  subject,  are, 

1.  Sulphuretted  Hydrogen,  composed  of 
hydrogen  holding  sulphur  in  solution, 
and  when  uncombined  with  a  base  assum- 
ing the  gasseous  form . 

2.  The  Hydrosulphurets,  or  combina- 
tions of  sulphuretted  hydrogen  with  the 
several  alkaline,  earthy,  and  metallic 
bases,  in  which  its  action  strongly  resem- 
bles that  of  an  acid. 

3-  The  Sulphurets,  or  combinations  of 
sulphur  with  the  alkalies,  earths,  and  me- 
tals. 

4.  Super  sulphuretted  Hydrogen,  or  sul- 
phuretted hydrogen,  with  a  considerable, 
but,  in  general,  an  uniform  excess  of  sul- 
phur. 

5.  Sulphuretted  Hydrosulphurets,  or 
combinations  of  sulphur,  sulphuretted  hy- 
drogen, and  the  alkaline  or  earthy  bases. 

SULPHURIC  ACID,  Vitriolic  Acid,  Oil 
of  Vitriol. — This  acid,  perhaps  the  most 
important  of  any  for  its  extensive  use,  is 
said  to  have  been  found  by  Baldassari  in 
a  concrete  state,  lining  a  grotto  in  mount 
St  Amiato  in  Tuscany  ;  it  also  occurs  in 
the  crevices  of  volcanic  mountains,  and 
dissolved  in  a  few  mineral  waters  It  is 
not,  however,  from  any  of  these  sources 
that  the  sulphuric  acid  of  commerce  is  ob- 
tained, the  whole  of  this  being  procured 
either  from  the  distillation  of  sulphat  of 
iron,  or  from  the  combustion  of  sulphur. 

Sulphat  of  iron  (or  green  vitriol)  as  we 
have  elsewhere  shown,  consists  of  sulphu- 
ric acid,  water,  and  oxyd  of  iron  ;  by  pro- 
per methods  the  acid  may  be  separated 
from  the  other  ingredients  of  the  salt ;  and 
this  continued  to  be  the  only  origin  of  sul- 


SUL 

phuric  acid  in  the  great  way,  till  the  dis- 
covery, by  the  manufacturing  English 
chemists,  of  the  art  of  preparing  it  by  the 
combustion  of  sulphur.  As  this  latter  dis- 
covery has  not,  however,  as  yet  entirely 
superseded  the  former,  we  shall  give  an 
account  of  both,  beginning  with  the  most 
ancient. 

Sulphuric  acid  is  thus  prepared  at  Blcyl 
in  Bohemia.  A  long  horizontal  furnace: 
or  gallery  of  brick-work  is  constructed 
capable  of  receiving  a  number  of  retorts  ; 
the  retorts  themselves  are  pear-shaped 
vessels,  with  a  slightly  curved  neck,  b/ 
which  they  lit  into  earthen  receivers  near- 
ly of  the  form  of  common  retorts.  The 
whole  apparatus  being  prepared,  each  re- 
tort is  charged  with  3  lbs.  of  sulphat  of 
iron,  previously  calcined  at  a  lull  red  heat, 
and  the  fire  is  lighted.  The  first  effect 
of  the  heat  is  to  drive  oft"  the  moisture  ab- 
sorbed by  the  vitriol  in  the  interval  be- 
tween its  calcination  and  distillation  ;  this 
phlegm  being  only  very  slightly  acidu- 
lous is  allowed  to  escape,  and  when  it 
ceases  to  come  over,  the  receiver  with  a 
little  water  in  it,  is  luted  on  to  the  retort; 
the  fire  is  now  raised  and  kept  up  brisk 
for  32  hours,  during  which  time  the  acid 
rises  in  the  form  of  dense  white  vapours, 
which  fill  the  receiver,  and  are  there  ab- 
sorbed by  the  water.  These  vapours 
being  at  a  high  temperature  soon  render 
the  receiver  very  hot ;  hence  the  work- 
men judge  of  the  termination  of  the  pro- 
cess by  the  receiver  becoming  cool  in  con- 
sequence of  the  vapour  ceasing  to  rise. 
The  red  oxyd  of  iron  or  colcothar,  is  now 
taken  out  of  the  retort,  and  Its  place  is 
supplied  with  a  fresh  charge  of  calcined 
vitriol ;  the  distillation  then  takes  place  as 
already  described,  except  that  the  former 
produce  of  acid  is  not  emptied  out  of  the 
receiver,  and  therefore  there  is  no  occa- 
sion to  add  any  water.  If  the  retort  is 
well  made  and  carefully  luted  all  over,  it 
will  last  for  three  successive  distillations, 
and  the  quantity  of  acid  obtained  is  near- 
ly equal  to  half  the  weight  of  the  calcined 
sulphat. 

If  the  acid  be  examined  at  different  pe- 
riods of  the  distillation,  it  will  be  found 
to  be  more  and  move  dense,  according  to 
the'violence  of  the  fire  required  for  its  ex- 
trication ;  the  latter  portion,  if  received  in 
a  separate  ves-sel,  will  generally  congeal 
upon  cooling,  hence  it  is  called  glacial  sul* 
pimric  acid,-  this  property,  however,  is  not 
entirely  owing  to  its  density,  as  we  shall 
presently  show. 

The  sulphats  of  copper  and  unc  have 
occasionally  been  employed,  instead  of  the 
sulphat  of  iron,  but  with  a  manifest  disad- 
vantage, both,  because  they  are  derrr' 


SUL 


SUL 


than  the  latter  salt,  and  because  they  re- 
quire  a  higher  and  longer  continued  heat 
to  drive  off  the  whole  of  the  acid. 

The  following  is  the  usual  method  of 
manufacturing-  sulphuric  acid  from  the 
combustion  of  sulphur.  A  chamber  is 
constructed  of  frame  work,  and  lined  with 
strong  sheet  lead ;  the  only  aperture  is  a 
small  door,  made  to  shut  very  close,  the 
bottom  of  which  is  a  little  higher  than  the 
floor  of  the  chamber.  Water  is  poured 
into  this  chamber  till  it  rises  to  the  height 
of  an  inch  or  two  upon  the  floor,  and  a 
stand  is  introduced  on  which  is  placed  an 
earthen  pot,  containing  a  few  pounds  of 
sulphur  and  nitre,  in  the  proportion  of 
from  eight  to  ten  of  the  former  to  one  of 
the  latter ;  this  mixture  is  set  fire  to,  by 
means  of  a  red  hot  iron,  and  the  door  is 
immediately  closed ;  at  the  expiration  of 
about  six  hours  a  second  charge  of  sul- 
phur and  nitre  is  introduced,  which  after 
a  similar  interval  is  replaced  by  a  third, 
and  so  on,  without  intermission,  for  a  fort- 
night or  three  weeks.  At  the  end  of  this 
period,  the  water  in  the  chamber  is  suffi- 
ciently acidulated ;  it  is  accordingly  trans- 
ferred to  a  leaden  boiler,  where  the  greater 
part  of  the  water  is  evaporated ;  in  pro- 
portion, however,  as  the  acid  becomes 
more  concentrated,  it  is  more  disposed  to 
corrode  and  dissolve  the  lead  of  the 
boiler ;  therefore,  before  this  degree  of 
concentration  takes  place,  the  liquor  is 
transferred  into  large  green  glass  retorts, 
where  a  degree  of  heat  is  applied  suffi- 
cient to  drive  off  almost  the  whole  of  the 
water.  As  the  acid  becomes  stronger,* it 
also  becomes  clearer  and  less  coloured  in 
consequence  of  a  portion  of  acid  reacting 
on  the  impurities  with  which  it  is  tinged, 
and  thus  destroying  them.  When  the 
acid  is  thus  brought  to  the  required  den- 
sity and  clearness,  it  is  poured  out  of  the 
retorts  into  large  globular  glass  bottles, 
surrounded  with  wicker  work  stuffed  with 
straw  (called  carboys)  and  is  then  brought 
into  the  market,  under  the  name  of  Oil  of 
Vitriol. 

The  sulphuric  acid  obtained  from  the 
distillation  of  green  vitriol  exists  ready 
formed  in  the  salt,  its  extrication  is  a  per- 
fectly simple  process,  and  the  only  impu- 
rities that  it  can  possibly  contain  are  sul- 
phurous acid,  and  a  very  minute  portion 
of  oxyd  of  iron,  and  of  the  earth  of  there- 
tort.  '  When  loaded  with  sulphurous  acid 
it  has  a  suffocating  odour,  and  when  ex- 
posed to  the  air  gives  out  a  white  vapour 
like  strong  muriatic  acid :  it  used  former- 
ly to  be  sold  in  this  state  by  the  name  of 
fuming  oil  of  vitriol,  and  was  further  dis- 
tinguished by  its  property  of  congealing 
into  a  soft  ice,  at  a  very  moderate  degree 


of  cold.  By  dilution  with  a  little  water, 
and  subsequent  boiling  for  a  few  minutes 
in  a  glass  vessel,  the  sulphurous  acid  is 
driven  off,  and  the  residual  fluid  is  com- 
mon sulphuric  acid  in  a  state  of  very  con- 
siderable  purity. 

It  might  be  imagined  a  priori ,  that  sul- 
phur would  be  convertible  by  simple  com- 
bustion into  sulphuric  acid ;  this,  how- 
ever, is  by  no  means  the  case.  In  the  first 
rude  attempts'to  obtain  sulphuric  acid  by 
this  process,  the  method  employed  was 
the  following:  a  large  shallow  bason  was 
half  filled  with  hot  water,  and  an  earthen 
crucible,  or  other  convenient  vessel,  filled 
with  melted  and  ignited  sulphur,  was 
fixed  by  means  of  a  stand  in  the  middle 
of  the  bason,  and  just  above  the  surface 
of  the  water ;  a  large  bell  glass  was  then 
whelmed  over  the  pot  of  sulphur,  and 
brought  nearly,  though  not  quite  in  con- 
tact with  the  water;  in  this -situation  the 
vapour  arising  from  the  combustion  of  the 
sulphur,  rose  into  the  bell  glass,  where  it 
mixed  with  the  steam  of  the  hot  water, 
and  condensing,  trickled  in  drops  down 
the  sides  of  the  glass  into  the  bason.  But 
though  by  this  process  a  certain  quantity 
of  sulphuric  acid  was  obtained,  yet  so 
large  a  portion  of  the  sulphur  escaped  in 
incondensible  suffocating  sulphurous  acid 
gas,  as  to  render  it  both  a  very  offensive 
and  uneconomical  mode  of  proceeding. 
Nor  does  the  want  of  success  in  these  ex- 
periments appear  to  have  arisen  from  any 
imperfection  of  the  apparatus,  or  want  of 
care  in  the  manipulation,  for  they  have 
since  been  repeated  by  various  manufac- 
turers on  a  great  scale,  but  with  the  same 
result  as  at  first.  Chaptal  appears  to  have 
bestowed  particular  care  on  this  subject ; 
we  shall,  therefore,  state  the  results  of 
his  experiments.  The  apparatus  employ- 
ed by  this  able  chemist,  was  a  leaden 
chamber,  with  a  stove  constructed  on  the 
outside,  and  communicating  by  means  of 
a  flue  with  the  chamber.    In  this  stove 
the  sulphur  was  melted,  and  a  blast  of 
air  being  directed  on  its  surface,  combus- 
tion took  place,  and  the  products  of  this 
combination  passed  into  the  leaden  cham- 
ber, and  were  thus  brought  in  contact 
with  the  water  which  it  contained.  When 
the  current  of  air  passed  very  rapidly 
over  the  sulphur,  only  a  very  small  quan- 
tity of  this  latter  suffered  combustion,  the 
greater  part  being  simply  involved  in  the 
air  in  a  minutely  divided  state,  and  depo- 
sited within  the  chamber  in  the  form  of 
flowers  of  sulphur.    By  moderating  the 
rapidity  of  the  current  of  air,  the  combi- 
nation of  the  sulphur  with  oxygen  is  more 
complete,  a  large  quantity  of  sulphurous 
!  acid  is  produced,  and  part  of  the  sulphur 


SUL 


SUL 


is  found  covering  the  surface  of  the  wa- 
ter in  form  of  a  thin  elastic  skin.  If  the 
current  of  air  is  rendered  still  slower,  so 
as  but  just  to  keep  up  the  combustion,  the 
whole  of  the  sulphur  is  acidified,  but  so 
large  a  portion  of  it  is,  in  the  state  of  in- 
condensible  gas,  that  the  product  of  true 
sulphuric  acid  is  altogether  insignificant. 
In  one  of  M.  ChaptaPs  experiments  he 
burnt  in  the  course  of  seven  days  1135  lbs. 
ot  sulphur,  at  the  end  of  which  time  so 
prodigious  a  quantity  of  suffocating  gas 
poured  rout  from  the  chamber  as  to  render 
it  necessary  to  stop  the  process  ;  in  three 
or  four  days  after,  the  door  of  the  cham- 
ber was  opened,  and  after  the  gas  had 
escaped,  it  was  found  that  the  water  on 
the  floor  of  the  chamber  was  covered  with 
a  flexible  skin  of  sulphur,  and  was  scarce- 
ly at  all  acidulous  to  the  taste. 

Jn  a  second  experiment  the  combustion 
was  much  slower,  2900  lbs  being  burnt 
in  the  space  of  thirty-three  days  ;  during 
the  process  much  sulphurous  acid  gas  es- 
caped, and  on  the  chamber  being  opened 
there  was  no  appearance  of  sublimed  Sul- 
phur or  of  film  upon  the  water,  so  that 
the  whole  of  the  sulphur  had  undergone 
Combustion,  but  the  product  of  condensi- 
ble  acid  wai  so  small  that  the  water  was 
only  sHirhtly  acidulous,  and  scarcely  ef- 
fervesce;! with  carbonated  alkali.  Hence 
it  appears,  that  though  atmospheric  air 
will  effect  the  combustion  of  sulphur,  yet 
the  product  is  little  else  than  incondensi- 
ble  sulphurous  acid. 

Several  other  methods  have  been  tried 
to  supersede  the  necessity  of  employing 
nitre,  but  with  little  or  no  success.  Water 
contains  a  large  proportion  of  oxygen  in 
its  composition,  and  is  readily  decom- 
posable at  a  moderate  heat  by  a  variety  of 
substances,  attempts  have  been  accord- 
ingly made  to  employ  it  for  the  oxygena- 
tion of  sulphur  if  to  some  of  this  latter, 
when  melted  and  ignited,  there  be  added 
water  drop  by  drop,  at  short  intervals,  the 
flame  of  the  sulphur  will  be  enlarged,  its 
colour  will  become  of  a  yellowish  tinge, 
and  a  dense  white  vapour  will  arise  from 
it;  but  this  latter,  when  condensed,  ap- 
pears to  be  only  very  slightly  acidulated 
water,  highly  charged  with  minutely  di- 
vided sulphur.  A  more  likely  method  of 
producing  sulphuric  acid  was  by  mixing 
with  the  sulphur  a  portion  of  black  oxyd 
of  manganese,  capable  of  furnishing  a 
quantity  of  oxygen  equal  to  that  contain- 
ed in  the  proportion  of  nitre  usually  em- 
ployed ;  but  though  this  mixture  has'  been 
treated  in  various  ways,  it  does  not  ap- 
pear capable  of  furnishing  a  greater  quan- 
tity of  sulphuric  acid,  than  when  sulphur 
is  simply  burnt  in  atmospheric  air.  Even 

VOL.  II.  1 


oxygen  gas  itself,  when  distributed  by 
means  of  a  pipe  over  the  surface  of  heat- 
ed sulphur;  is  by  no  means  comparable  in 
efficacy  to  nitre  :  the  rapidity  of  the  com- 
bustion is  indeed  very  rapidly  increased, 
but  the  product  is  almost  entirely  sulphu- 
rous acid  gas. 

When  the  method  of  producing  sulphu- 
ric acid  by  the  combustion  of  sulphur  and 
nitre  was  first  discovered,  the  apparatus 
employed  was  a  series  of  very  large  glass, 
balloons,  at  the  bottom  of  each  of  which 
was  a  little  water  to  condense  the  va- 
pour; only  a  small  quantity  of  the  mix- 
ture could  be  burnt  at  once,  and  constant 
supei  intendance  was  necessary  to  supply 
the  balloons  with  fresh  charges  of  the 
materials.  In  order  to  save  much  of  this 
manual  labour,  and  the  heavy  loss  arising 
from  the  frequent  fracture  of  the  vessels, 
leaden  chambers  were  made  use  of,  which 
besides  requiring  less  attendance,  and  be- 
ing upon  the  whole  cheaper,  rendered  it 
easier  for  the  manufacturer  to  extend  his 
establishment  to  any  required  magnitude. 
These  chambers  are  of  various  construc- 
tion ;  the  most  simple  and  in  most  gene- 
ral use,  are  furnished  only  with  two  aper- 
tures, namely,  a  small  door,  by  which  the 
water  and  the  sulphur  and  the  nitre  are 
introduced,  and  a  leaden  pipe  with  a  stop) 
cock,  by  which  the  water,  when  acidu- 
lated, is  drawn  off ;  other  chambers  have 
besides  a  few  small  apertures  for  the  in- 
troduction of  atmospheric  air  during  the 
combustion,  and  a  steam  pipe  connected 
with  a  boiler,  it  being  found  that  if  the 
water  is  introduced  in  the  state  of  steam, 
a  much  more  rapid  condensation  of  the 
acid  ensues  than  in  the  usual  way  of  pro- 
ceeding. In  some  of  the  best  contrived 
chambers  the  combustion  of  the  nitre  and 
sulphur  is  effected  in  a  separate  stove, 
and  the  acid  vapour  thus  produced  is 
poured  by  means  of  a  pipe  into  the  con- 
densing chamber. 

There  is  a  good  deal  of  difference 
among  the  manufacturers  as  to  the  pro- 
portion of  nitre  employed;  by  some  it  is 
made  equal  to  one-fifth  of  the  sulphur, 
while  by  others  it  is  not  allowed  to  exceed 
one-tenth.  This,  however,  appears  to  be 
satisfactorily  established,  that  within  the 
above  limits  the  greater  the  proportion  is 
of  nitre,  the  more  easily  condensible  "'ill 
the  acid  vapour  be,  and  the  less  sulphur 
will  be  lost  in  the  form  of  sulphurous  acid 
gas.  If  the  nitre  exceeds  prfe-fifth  of  the 
sulphur,  the  combustion  be  so  rapid 
as  to  drive  into  the  chamber  a  considera- 
ble proportion  of  sulphur  unaltered.  The 
acid  vapour  is  of  a  dense  opake  white  co- 
lour, and,  according  to  Chaptal,  is  const- 
derablv  luminous  :  when  as  much  of  it  h 


SUL 


SUL 


condensed  as  is  capable  of  being  so  in  the 
usual  process,  the  residue  becomes  quite 
transparent,  and  is  for  the  most  part  a 
mixture  of  sulphurous  acid  gas  and  ni- 
trous gas  ;  it  has  a  peculiar  and  very  pun- 
gent suffocating  odour,  and  upon  opening 
the  -ioor  of  the  chamber,  it  presently  ac- 
quires  a  faint  orange  red  colour,  by  com- 
bining with  the  oxygen  of  the  air,  and 
thus  forming  nitrous  acid  vapour;  this, 
as  soap  as  formed,  re-acts  on  the  leaden 
lining  of  the  chamber,  corroding  it  deep- 
ly, and  is  the  principal  cause  of  the  sul- 
phat  of  lead,  which  common  sulphuric 
acid  always  contains,  and  often  in  consi- 
derable abundance.  It  would  conduce 
much  to  the  purity  of  sulpharic  acid,  and 
might  probably  be  found  even  to  be  an 
economical  plan,  to  line  the  chamber  with 
glass  instead  of  sheet  lead  ;  the  general 
appearance  of  the  chamber  would  then 
resemble  a  green-house,  and  all  the  wood 
work  should  be  faced  internally  with 
glass  ;  a  composition  of  wax,  mastich  and 
fine  sand,  would  form  a  strong  cement  for 
the  glass,  and  little  liable  to  be  acted  on 
by  acid  vapours,  more  especially  if  the  in- 
terstices filled  up  with  it  were  dusted  with 
powdered  gbss  or  very  hue  sand,  while 
the  cement  was  yet  warm  and  adhesive. 
Such  a  chamber  would  have  the  addi- 
tional advantage  of  allowing  the  operator 
to  see  what  was  passing  within,  without 
the  necessity  of  opening  the  door. 

With  regard  to  the  strength  of  the  acid 
when  withdrawn  from  the  condensing 
chamber,  we  are  informed  by  Chaptal, 
that  in  his  manufactory  it  used  to  mark 
between  40°  and  50°  on  Beaume's  areo- 
meter ;  it  was  then  evaporated  in  leaden 
boilers,  till  it  arrived  at  60°  of  Beaume, 
and  was  lastly  condensed  in  glass  retorts 
till  it  was  equal  to  66°,  and  was  then  at 
the  common  density  of  the  oil  of  vitriol  of 
commerce.  We  are  told  by  the  same  au- 
thor, that  one  part  of  sulphur  affords 
nearly  two  parts  of  sulphuric  acid  at  the 
above  density  :  this,  however,  appears  to 
be  a  mistake  We  should  imagine  that 
in  the  common  manufactories  the  loss  by 
sulphurous  acid  gas  would  nearly  coun- 
terbalance the  increase  from  the  addition 
of  oxygen  and  water ;  indeed  it  is  ex- 
pressly stated  by  some  authors  that  100 
pounds  of  sulphur  produce  by  combus- 
tion w-i  equal  weight  of  sulphuric  acid. 

It  has  been  already  mentioned  that  the 
common  English  sulphuv  (and  probably 
all  that  which  is  obtained  during  the  roast-* 
ing  of  copper  ore )  &  unfit  for  t\ie  prepa- 
ration of  sulphuric  acid5  on  account  of  a 
yellowish-brown  colour  that  it  gives  to 
t  his  fluid,  and  which  it  is  extremely  diffi- 
cult to  get  rid  of.    For  this  reason  the 


refined  Sicilian  sulphur  is  the  only  kind 
that  is  employed  in  this  manufacture,  at 
least  in  Britain.  But  though  by  the  due 
selection  of  sulphur  one  source  of  impu- 
rity is  avoided,  yet  there  are  others  which, 
according  to  the  usual  mode  of  preparing 
this  acid,  it  is  impossible  to  escape.  The 
watery  acid,  as  it  runs  from  the  leaden 
chamber,  is  necessarily  mixed  with  sul- 
phat  of  lead,  with  a  small  quantity  of  ni- 
trous acid,  and  holds  suspended  in  a  mi- 
nutely divided  state,  a  portion  of  sulphur, 
from  which  it  acquires  a  yellowish  colour: 
during  the  evaporation  in  the  leaden  boil- 
ers, probably  a  little  more  sulphat  of  lead 
is  taken  up.  The  high  heat  required  for 
the  final  concentration  of  the  acid  in  the 
glass  retorts,  by  causing  the  nitrous  and 
part  of  the  sulphuric  acid  to  re-act  on  the 
diffused  sulphur  and  other  inflammable 
impurities,  takes  away,  for  the  most  part, 
the  colour  from  the  "fluid,  and  drives  off 
the  whole  of  the  nitrous  gas  and  sulphu- 
rous acid,  together  with  a  portion  of  wa- 
ter :  thus  the  only  impurity  that  finally  re- 
mains in  the  sulphuric  acid  is  sulphat  of 
lead.  But  it  not  imfrequently  happens 
that  the  acid,  during  concentration,  loses 
its  colour  very  slowly,  to  expedite  which 
it  is  usual  to  add  a  little  nitre,  the  acid  of 
which  being  set  at  liberty,  acts  rapidly  on 
the  colouring  matter  and  destroys  it,  be- 
ing itself  finally  driven  off  in  the  state  of 
nitrous  gas.  The  alkaline  base  of  the 
nitre,  however,  remains  dissolved  and 
combined  with  the  sulphuric  acid,  so  that 
besides  sulphat  of  lead,  it  is  further  con- 
taminated by  sulphat  of  potash ;  and  if  the 
nitre  is  added  somewhat  in  excess,  and 
only  a  little  while  before  the  concentra- 
tion is  finished,  it  is  very  probable  that  a 
portion  of  nitrous  acid  will  still  remain. 
Nor  is  it  of  trifling  moment  that  the  whole 
of  the  nitrous  acid  should  be  expelled  ; 
for  if  the  dyer  or  calico  printer  employs 
an  impure  acid  of  this  description  in 
making  Saxon  blue  (sulphat  of  indigo)  he 
will  find  to  his  cost  that  he  has  got  a 
green  instead  of  a  blue  pigment.  From 
the  occasional  occurrence  of  the  above 
and  other  similar  disappointments,  it  is 
that  the  dyers  on  the  continent,  when  they 
can  procure  either  the  sulphuric  or  the 
genuine  vitriolic  acid,  always  prefer  the 
latter,  notwithstanding  the  great  supe- 
riority of  its  price. 

Common  sulphuric  acid  may  be  freed 
from  the  sulphats  of  lead  and  potash 
which  it  generally  contains,  by  distilla- 
tion ;  this  however,  though  apparently  a 
very  simple  process,  is  rather  a  nice  mat- 
ter to  manage,  according  to  the  usual  me- 
thod. Sulphuric  acid  is  not  capable  of 
being  distilled  at  less  than  a  red  heat ; 


SUL 


SUL 


when,  therefore,  the  dense  hot  vapour 
first  comes  in  contact  with  the  necks  of 
the  retort  and  receiver,  it  is  apt  to  break 
Them,  unless  the  precaution  has  been 
taken  of  thoroughly  heating  them  by 
means  of  a  pan  of  charcoal  placed  be- 
neath, a  minute  or  two  before  the  distil- 
lation commences.  All  this  risk,  how- 
ever, may  be  avoided  (and  in  some  labo- 
ratories it  actually  is  so)  by  connecting 
the  glass  body,  In  which  the  acid  is  boil- 
ed, with  the  receiver,  by  means  of  a  tube 
of  platina :  boiling  sulphuric  acid  has  not 
the  least  action  on  this  metal,  and  the  va- 
pour in  its  passage  through  becomes  so 
far  cooled  and  condensed,  that  it  flows 
into  the  receiver  in  drops. 

The  manufacture  of  vitriolic  acid  is 
thus  given  by  Thomas  Cooper,  esq.  Pro- 
fessor of  Chemistry  in  Dickinson  college, 
Carlisle ;  extracted  from  the  Archives  of 
Useful  Knowledge. 

Set  up  the  frame  of  a  room,  20  feet  by 
30  feet,  and  18  feet  high.  Of  this  room, 
the  sides  and  the  ceiling  should  be  lined 
with  milled  lead,  about  6  lb.  to  the  foot. 
The  bottom  should  be  of  lead  81b  to  the 
foot,  with  a  plug  to  let  off  the  liquor  close. 
Two  feet  six  inches  from  the  bottom,  on 
the  20  foot  side,  should  be,  at  equal  dis- 
tances from  the  sides  and  from  each  other, 
two  trap  doors,  eighteen  inches  square, 
that  move  up  and  down  in  a  groove  by 
means  of  a  pulley.  Opposite  to  each  of 
these  trap  doors  should  be  an  iron  frame 
about  a  foot  wide  in  the  clear,  and  set  on 
leaden  feet,  or  lumps  of  lead,  four  inches 
at  least  from  the  bottom  of  the  room. 
Bach  of  these  frames  are  destined  to  hold 
three  or  tour  stone  ware,  or  porcelain 
pans,  15  inches  diameter,  and  4  inches 
deep,  which  are  to  be  half  filled  with 
brimstone  and  saltpetre,  ground  together 
and  sifted,  in  the  proportion  of  8r9ths  of 
brimstone  and  l-9th  of  saltpetre.  Fix  the 
pans  on  the  irames  or  tressels,  light  the 
mixture  by  a  red-hot  iron,  shut  the  trap 
doors,  and  let  them  burn.  The  nitre  sup- 
plies oxygen  to  the  sulphur,  which  is  con- 
verted into  volatile  vitriolic  acid.  If  water 
could  be  admitted  on  the  top  and  outside 
of  the  room,  the  condensation  would  be 
assisted.  Much  volatile  nitrous  acid  is 
also  disengaged  by  the  action  of  the  new- 
formed  vitriolic  acid  on  the  saltpetre, 
which  may  occasionally  be  let  out  by  a 
trap  door  on  pullies,  towards  the  top"  of 
the  further  side  of  the  room.  When  the 
pans  of  the  mixture  are  extinguished, 
leave  the  room  close  for  an  hour  before 
you  take  them  out ;  then  empty,  fill,  and 
light  them  again.  After  three  burnings, 
a  jet  of  cold  water  may  be  thrown  in  by  a 
hand  pump,  so  as  to  extend  in  a  scatter- 


ed rain-like  stream  through  the  room. 
Then  open  the  trap  doors,  and  admit  a 
current  of  air.  Do  not  throw  in  too  much 
cold  water,  as  it  will  require  more  fuel. 
Draw  oft' the  contents  at  the  bottom,  and 
evaporate  for  two  hours  by  a  strong  fire, 
in  leaden  retorts,  or  pans  ;  then  finish  in 
large  glass  retorts  in  a  sand  bath  In 
England,  the  glass  retorts  hold  90  lbs.  of 
oil  of  vitriol,  when  concentrated,  which  is 
one  half  too  much,  for  unless  the  men  are 
very  careful,  they  are  apt  to  break  them. 
In  Scotland  they  concentrate  entirely  in 
lead  Oil  of  vitriol  should  weigh  29  h  oz. 
to  the  wine  pint,  measured  and  weighed  in 
a  Florence  flask,  &c.  The  residue  of  the 
pans  may  be  ground  with  the  brimstone 
and  burnt  again.  The  pans  would  be  bet- 
ter if  they  ran  upon  small  inch  wheels  in 
a  groove  in  the  frame,  and  were  drawn 
out  by  a  crooked  iron. 

Sulphuric  acid,  when  pure,  is  perfectly 
transparent,  and  colourless  ;  but  the  com- 
mon oil  of  vitriol  of  the  shops  has  almost 
always  a  very  pale  hair  brown  tinge,  pro- 
bably arising  from  the  carbonization  of  a 
little  of  the  cement  with  which  the  bottles 
in  which  it  is  kept  are  closed  In  its  ge- 
neral appearance  and  consistence,  when 
shaken,  it  is  not  unlike  oil,  whence  it  de- 
rived its  commercial  name,  oil  of  vitriol. 
It  is  entirely  inodorous  :  to  the  touch  it  is 
at  first  smooth  and  unctuous,  but  it  pre- 
sently after  excites  a  violently  burning- 
sensation,  and  corrodes  the  skin  with 
great  rapidity  ;  even  when  largely  diluted 
with  water,  it  is  acerb  and  intensely  sour, 
and  sets  the  teeth  on  edge.  It  changes 
most  vegetable  blues  to  red,  and  exhibits 
the  other  generic  characters  of  acids  in  an 
eminent  degree. 

The  sulphuric  acid  is  considerably  den- 
ser than  any  other  acid  or  transparent 
fluid,  and  in  general  its  affinities  are 
stronger.  It  strongly  attracts  water, 
which  it  takes  from  the  atmosphere  very 
rapidly,  and  in  larger  quantities,  if  suffer- 
ed to  remain  in  an  open  vessel,  imbibing 
one  third  of  its  weight  in  twenty-four 
hours,  and  more  than  six  times  its  weight 
in  a  twelvemonth.  If  four  parts  by  weight 
be  mixed  with  one  of  water  at  50°,  they 
produce  an  instantaneous  heat  of  300u 
Fahrenheit;  and  four  parts  raise  one  of 
ice  to  212°  :  on  the  contrary  four  parts  of 
ice,  mixed  with  one  of  acid,  sink  the  ther- 
mometer to  4°  below  0.  When  pure  it  is 
colourless,  and  emits  no  fumes.  If  it  be 
heated,  it  becomes  more  and  more  con- 
centrated by  the  loss  of  a  portion  of  wa- 
ter, which  rises  before  the  acid  itself.  Its 
specific  gravity  ought  to  be  1.83,  at  which 
it  is  taken  by  the  London  college ;  but  it 
may  be  brought,  by  evaporation  in  a  sand 


SUL 


SUL 


heat,  to  2  or  upward.  At  this  strength  it 
requ.res  a  great  degree  of  cold  to  freeze 
it  ;  and  if  diluted  with  half  a  part  or  more 
of  water,  unless  the  dilution  be  earned 
very  fur,  it  becomes  more  and  more  diffi- 
cult to  congeal ;  yet  at  the  specific  gra- 
vity of  1.78,  or  a  few  hundredths  above 
or  below  this,  it  may  be  frozen  by  sur- 
rounding it  with  melting  snow.  Its  con- 
gelation forms  regular  prismatic  crystals 
with  .»ix  sides.  Its  boiling  point,  accord- 
ing to  Bergman,  is  540°,  according  to  Dal- 
ton  590°. 

Attempts  have  been  made  to  ascertain 
the  proportions  of  the  constituent  princi- 
ples in  this  acid,  but  chemists  have  differ- 
ed considerably  on  this  head.  Tromsdoi  f 
carries  the  sulphur  as  high  as  70  per  cent, 
and  Berthollet  even  to  73,  while  Klaproth, 
Richter,  and  Bucholz,  make  it  little  more 
than  42.  Lately  Mr.  Chenevlx  has  made 
some  very  careful  experiments  on  the 
subject,  which  give  51.5  for  the  propor- 
tion of  sulphur,  and  their  accuracy  is 
strengthened  by  others  made  by  Doctor 
Thomson  of  Edinburgh  ;  and  it  is  proba- 
ble the  other  chemists  may  have  erred 
from  mistaken  calculuations  of  the  com- 
ponent parts  of  the  salts  employed  in  the 
analysis. 

The  sulphuric  acid  is  of  very  exten- 
sive use  in  the  art  of  chemistry,  as  well 
as  in  metallurgy,  bleaching,  and  some 
of  the  processes  for  dyeing :  in  medicine 
it  is  given  as  a  tonic,  stimulant,  and  li- 
thontriptic,  and  sometimes  used  exter- 
nally as  a  caustic. 

The  combinations  of  this  acid  with  the 
various  huses  are  called  sulphats,  and 
most  of  them  have  long  been  know  by  va- 
rious names  For  further  particulars  con- 
sult the  different  authors  on  chemistry. 

SULPHUREOUS  ACID.  This  acid,  as 
used  in  the  arts,  is  employed  particular- 
ly in  the  bleaching  of  straw,  silk,  flannels, 
&c.  which  is  used,  however,  only  in  a 
certain  manner.  See  Bleaching.'  The 
acid,  in  a  liquid  state,  or  the  sulphureous 
acid  gas  combined  with  water,  however, 
is  seldom  employed ;  but  the  acid  in  the 
aeriform  state,  is  the  most  general  mode 
of  applying  it.  The  goods  are  moistened, 
and  exposed,  in  a  confused  situation,  to 
the  gas  produced  by  the  slow  combustion 
of  sulphur. 

As  the  acid  obtained  by  burning  sulphur 
in  this  way,  is  commonly  mixed  with  more 
or  less  sulphuric  acid,  when  sulphurous 
acid  is  wanted,it  is  commonly  made  by  ab- 
stracting part  of  the  oxygen,  from  sulphu- 
ric acid,  by  means  of  some  combustible 
substance.  Mercury  or  tin  is  usually  pre- 
ferred. Tor  the  purposes  of  manufac- 
tures, however,  chopped  straw  or  saw- 


dust, may  be  employed.  If  one  part  of 
mercury,  and  two  of  concentrated  sulphu- 
ric acid  be  put  into  a  glass  retort  with  a 
long  neck,  and  heat  applied  till  an  effer- 
vescence is  produced,  the  sulphurous 
acid  will  arise  in  the  form  of  gas,  and  may 
be  collected  over  quicksilver,  or  received 
into  water,  which  at  the  temperature  of 
sixty-one  degrees,  will  absorb  thirty-three 
times  its  bulk,  or  nearly  an  eleventh  of  its 
weight. 

Water  thus  saturated,  is  intensely  acid 
to  the  taste,  and  has  the  smell  of  sulphur 
burning  slowly  It  destroys  most  vegeta- 
ble colours,  but  the  blues  are  reddened 
by  it,  previous  to  their  being  discharged. 
A  pleasing  instance  of  its  effect  on  co- 
lours may  be  exhibitted,  by  holding  a 
red  l  ose  over  the  fumes  of  burning  sul- 
phur. 

Sulphuring  is  generally  performed  in 
the  large  way,  in  an  arched  or  very  close 
chamber,  constructed  in  such  a  manner, 
that  the  articles  to  be  exposed  to  the  ac- 
tion of  the  sulphur  can  be  suspended  on 
poles.  The  chamber  being  filled,  a  cer- 
tain quantity  of  sulphur,  is  put  in  a  state 
of  combustion  in  flat  dishes,  having  a  large 
surface,  with  very  little  depth  ;  the  en- 
trance is  speedily  shut,  and  all  the  inter- 
stices around  the  door  are  carefully  stop- 
ped, to  prevent  the  access  of  the  atmos- 
pheric air.  The  acid  generated  by  the 
combustion  of  the  sulphur,  penetrates  the 
stuffs,  attacks  the  colouring  matter,  de- 
stroys it,  and  effects  the  bleaching.  The 
stuffs  are  left  in  the  stoves  sometime  af- 
ter the  deflagration  has  ceased. 

This  time  varies  from  6  to  24  hours. 
They  are  then  taken  out,  and  made  to 
pass  through  a  slight  washing  with  soap, 
to  remove  the  roughness  they  have  ac- 
quired by  the  action  of  the  acid,  and  to 
give  them  the  necessary  softness. 

This  process  is  imperfect.  At  first,  the 
acid  of  the  sulphur  acts  only  on  the  sur- 
faces, and  does  not  penetrate.  This  aerial 
immersion  is  not  sufficient ;  the  gas  can- 
not introduce  itself,  to  a  sufficient  depth 
into  the  stuffs,  and  the  superfices  only 
are  whitened. 

A  superior  method  has  been  lately  in- 
vented, which  is  by  making  use  of  the 
sulphureous  acid,  as  before  slated. 

The  pieces  are  rolled  upon  the  reels, 
and  are  drawn  through  the  sulphureous 
acid,  or  water  impregnated  with  the  gas, 
by  turning  them,  until  it  is  observed  that 
the  whiteness  is  sufficiently  bright.  They 
are  then  taken  out,  and  are  left  to  drain 
on  a  bench  covered  with  cloth,  lest  they 
should  be  stained  in  consequence  of  the 
decomposition  of  the  wood  by  the  sulphu- 
reous acid  ;  they  are  next  washed  in  river 


SWE 


SWE 


water,  and  Spanish  white  is  employed,  if 
it  should  be  judged  necessary.  This  ope- 
ration is  performed  by  passing  the  pieces 
through  a  tub  of  clear  water,  in  which 
about  eight  pounds  of  Spanish  white  have 
been  dissolved.  To. obtain  a  fine  white- 
ness, the  stuffs,  in  general,  are  twice  sul- 
phured. According  to  this  process,  one 
immersion  and  reeling  two  or  three  hours, 
is  sufficient. 

SUMAC  OR  SHUMAC.  Besides  the 
remarks  under  the  head  of  shumac,  we 
thought  it  better  to  add  a  few  observa- 
tions on  some  of  the  chemical  properties 
of  this  plant,  more  especially  on  its  use 
in  dyeing 

Common  sumach  (rhus  coriaria)  is  a 
shrub  thai  grows  naturally  in  Syria,  Pales- 
tine, Spain,  Portugal,  and  America  ;  its 
shoots  are  cut  down  every  year  quite  to 
the  root ;  and  after  being  dried,  they  are 
reduced  to  powder  by  a  mill,  and  thus 
prepared  for  the  purposes  of  dyeing  and 
tanning.  The  sumach  cultivated  in  the 
neigbourhood  of  Montpelier,  is  called  re- 
doul  or  roudou. 

The  infusion  of  sumach,  which  is  of  a 
greenish  favvncolour,soon  becomes  brown 
by  exposure  to  the  air:  a  solution  of  po- 
tash, produces  but  little  change  on  it, 
while  recent ;  acids  brighten  its  colour, 
and  turn  it  yellow  ;  solution  of  alum  ren- 
ders it  turbid,  and  produces  in  it  a  small 
quantity  of  yellow  precipitate  ;  the  liquor 
remains  yellow. 

Mr.  Proust  has  shown,  that  sumach 
contains  abundance  of  sulphat  of  lime; 
and  it  is  probably  owing  to  this,  that  its 
infusion  gives  dense  precipitates,  with  the 
caustic  alkalies. 

Mr.  Hatchett  found,  that  an  ounce  con- 
tains about  seventy-eight  or  seventy-nine 
grains  of  tannin. 

Sumach  acts  on  a  solution  of  silver  just 
as  galls  do  :  it  reduces  the  silver  to  its 
metallic  state,  and  the  reduction  is  favour- 
ed by  the  action  of  light. 

Sumach  alone,  gives  a  fawn  colour  in- 
clining to  green  ;  but  cotton  stuffs,  which 
have  been  impregnated  with  printer's 
mordant,  that  is,  acetate  of  alumine,  take 
a  pretty  good  and  very  durable  yellow. 
An  inconvenience  is  experienced  in  em- 
ploying sumach  in  this  way,  which  arises 
from  the  fixed  nature  of  its  colour ;  the 
ground  of  the  stuff  does  not  lose  its  co 
lour  by  exposure  on  the  grass,  so  that  it 
becomes  necessary  to  impregnate  all  the 
stuff  with  different  mordants,  to  vary  the 
colours,  without  leaving  any  part  of  it 
white. 

SUN-FLOWER-OIL.    See  Oil. 
SWEDISH   STONE  PAPER.  The 
chief  use  of  this  paper  is  to  cover  houses; 


it  is  therefore  made  of  such  materials  as 
will  stand  the  weather.  As  paper  is  the 
basis,  it  is  evident  that  it  must  be  impreg- 
nated with  such  substances  as  will  have 
the  effect,  of  making  it  impervious  to 
water. 

The  Red  Stone  Paper. 

Is  made  of  martial  ball,  vegetable  mat- 
ter, animal  glue,  and  linseed  oil. 

The  White  and  Yellow  Stone  Taper, 

Has  the  same  materials,  except  the  ball, 
in  the  place  of  which  chalk,  ochre,  &c. 
are  used.  The  mode  of  preparation  con- 
sists in  forming  the  rags,  or  in  their  place, 
paper,  into  a  pulp  by  boiling  with  water  ; 
then  mixed  with  dissolved  glue,  and 
made  into  a  paste,  with  the  above  earthy 
or  ochrous  matters,  and  some  copperas, 
and  the  whole  beat  in  a  mortar  with  lin- 
seed oil.  The  mass  being  prepared  in 
this  manner,  is  to  be  spread  out  with  a 
spatula  above  a  sheet  of  coarse  paper, 
placed  on  a  board  furnished  with  a  rim  or 
border.  The  whole  being  inverted,  the 
board  with  the  rim  is  to  be  taken  off,  and 
the  compressed  mass  is  to  be  laid  upon 
another  board,  sprinkled  with  sand,  and 
left  to  dry,  after  taking  the  sheet  of  paper 
from  its  other  side.  Squares  made  in  this 
manner,  dry  without  cracking. 

AVe  shall  now  enumerate  some  experi- 
ments made  by  a  chemist,  in  his  investi- 
gations into  the  composition  of  this  paper, 
viz. 

"Experiment.  I.  1  mixed  an  ounce 
and  a  half  of  the  dry  pulp  from  the  mill, 
with  two  ounces  of  common  glue,  and, 
having  added  red  bole  and  ochre,  of  each 
two  ounces,  obtained  a  smooth  plate. 

"  II.  To  two  ounces  of  pulp  I  added 
four  ounces  of  red  bole  pulverized,  and 
half  an  ounce  of  chalk,  with  an  ounce  and 
a  half  of  glue.  The  plate  thus  produced 
was  full  of  wrinkles  and  chinks,  but  tole- 
rably hard. 

"  III.  An  ounce  and  an  half  of  pulp, 
with  four  ounces  of  bole,  and  two  of  snl- 
phat  of  iron,  produced  a  plate  equally 
hard,  but  uneven. 

"  I V.  An  ounce  of  pulp  procured  from 
old  paper,  and  bookbinders'  shavings, 
mixed,  with  half  an  ounce  of  glue,  one 
ounce  of  powdered  chalk,  two  of  bole,  and 
one  ounce  of  linseed  oil,  produced  two 
thin  plates  smooth  and  hard. 

"  V.  Two  ounces  of  pulp  from  the 
mill,  with  half  an  ounce  of  glue,  six  oun- 
ces of  red  bole,  and  two  of  chalk,  to  which 
were  added  two  ounces  of  sulphat  of  iron, 
and  the  same  quantity  of  linseed  oil,  af- 
forded plates  that  were  smooth,  but  not 
strong. 

"  VI.  An  ounce  and  a  half  of  pulp, 
with  an  ounce  of  glue,  and  four  ounces 


SAVE 


SYR 


of  white  bole,  produced  a  plate  smooth, 
beautiful  and  hard. 

"  VII.  An  ounce  and  a  half  of  pulp, 
mixed  with  two  ounces  of  glue,  two  oun- 
ces of  white  bole,  and  as  much  chalk, 
yielded  a  smooth  plate  as  hard  as  bone. 

"  VIII.  An  ounce  of  pulp,  one  ounce 
of  glue,  three  ounces  of  white  bole,  and 
an  ounce  of  linseed  oil,  produced  a  plate 
sufficiently  perfect  and  elastic. 

"  IX.  A  plate  which  I  formed  of  one 
ounce  of  pulp,  with  half  an  ounce  of  glue, 
three  ounces  of  white  bole,  one  ounce  of 
chalk,  and  one  ounce  and  a  half  of  lin- 
seed oil,  was  superior  to  that  mentioned 
in  the  preceding  experiment.  This  sub- 
stance retains  figures  impressed  upon  it, 
and  tinged  with  half  a  drachm  of  Prus- 
sian blue,  assumed  a  blueish-green  colour. 

"  X.  .\n  ounce  and  a  half  of  pulp,  with 
one  ounce  of  glue,  and  four  ounces  of 
chalk,  afforded  a  plate  exceedingly  spon- 
gy- 

"  XI.  An  ounce  and  a  half  of  the  same 
pulp,  one  ounce  of  sulphat  of  iron,  and 
four  ounces  of  white  bole,  without  glue, 
produced  a  plate  yellowish  and  spongy. 

"  XII.  An  ounce  and  a  half  of  pulp,  j 
four  ounces  of  white  bole,  with  an  ounce 
of  sulphat  of  iron,  and  the  same  quantity 
of  glue,  produced  a  yellowish  plate  a  little  j 
more  solid.  I 

"  The  cement  which  the  Swedes  recom-  i 
mend,for  filling  up  the  interstices  between 
the  squares,  is  composed  of  linseed  oil  i 


varnish,  white  lead  and  chalk,  mixed  to- 
gether in  such  a  manner,  as  to  approach 
to  a  fluid  state,  that  it  may  more  easily 
insinuate  itself  into  the  fissures 

"  As  the  chief  use  of  this  invention  is  to 
cover  and  incrust  houses,  I  was  desirous 
of  trying  my  production,  by  exposing  it 
to  the  effects  of  the  weather.  I  therefore 
nailed  fragments  of  the  Swedish  stone 
paper,  and  of  that  made  by  myself,  to  a 
small  board;  and  having  daubed  over  the 
joinings  with  cement,  I  exposed  them  in 
the  month  of  August,  on  the  top  of  my 
house,  and  in  the  beginning  of  April  the 
next  year,  I  found  they  had  undergone  no 
change  " 

.  SWINE.    See  Animals  Domestic. 

SYMPATHETIC  INKS.    See  Inks. 

SYPHON.    See  Hydrostatics. 

S\RUP.  This  is  a  preparation  of 
sugar,  made  by  dissolving  it  in  water, 
and  evaporating  it,  till  it  acquires  the  con- 
sistence of  soft  honey.  Simple  syrup  is  a 
solution  of  sugar  boiled  in  this  manner  ; 
molasses  or  treacle,  is  an  inferior  and  at 
the  same  time  an  impure  syrup.  In  the 
shops  of  the  confectioners  and  apotheca- 
ries, we  have  various  medicated  and  other 
syrups,  which  are  made  by  adding  other 
substances  to  the  simple  syrup,  or  by  the 
boiling  of  sugar  with  sundry  fluids.  Thus, 
syrup  of  vinegar,  lemon,  &c.  is  prepared 
by  boiling  sugar  in  vinegar,  or  lime  or 
lemon  juice,  till  it  acquires  the  due  con- 
sistence. 


T. 


TABLE,  Mill-Wrights* .  See  Mecha- 
nics. 

TABLE  BEER.    See  Beer. 

TACKLE.    See  Mechanics. 

TALC.  Magnesia  .44,  silex  .50,  and 
alumine  .06,  according  to  the  analysis  of 
Mr  Hoepfner,  constitute  Venetian  talc. 

Its  colour  is  white,  gray,  yellowish,  or 
greenish ;  it  is  soft  and  soapy  to  the 
touch,  and  in  thin  pieces  semitransparent; 
it  is  composed  of  very  thin  plates,  dispos- 
ed in  a  laminar  or  filamentous  form,  much 
tenderer  and  more  brittle  than  those  of 
mica,  but  like  this  it  has  a  metallic  lus- 
tre ;  its  hardness  is  so  inconsiderable,  that 
it  may  be  scratched  with  the  nail ;  and 
its  specific  gravity  is  2.729. 

It  does  not  effervesce  with  acids  ;  and 
is  soluble  therein  with  difficulty,  by  par- 
ticular management,  and  only  in  part. 

In  fire  it  becomes  more  brittle  and 


whiter,  but  is  infusible  per  se  by  the 
blowpipe,  and  scarcely  fusible  by  fixed  al- 
kali, but  more  completely  and  with  little 
effervescence  by  borax  or  microcosmic 
salt- 

Muscovy  talc  consists  of  broad,  elastic, 
flexible,  transparent  leaves ;  and  differs 
externally  from  mica  only  in  being  softer 
and  more  soapy  to  the  touch.  Its  analysis 
by  Vauquelin  gave  silex  .62,  magnesia 
.27,  oxide  of  iron  .035,  alumine  .015,  wa- 
ter .06. 

It  abounds  in  the  hills  of  Bahar,  and 
other  parts  of  India,  where  its  market 
price,  split  into  sheets  about  2  lines  thick, 
is  at  the  rate  of  24  lbs.  avoirdupois  for  a 
rupee  (2s.  6d.)  The  natives,  as  well  as 
the  Chinese,  make  very  splendid  lanterns, 
shades,  and  ornaments  of  it,  tinged  of  va- 
rious colours.  They  likewise  use  it  in 
medicine,  considering  it  when  calcined,  a 


TAL 


TAL 


specific  in  obstinate  coughs  and  consump- 
tions. Powdered,  it  makes  a  silver  sand 
for  writing. 

This  mineral  is  employed  in  preparing 
compositions  for  earthen  vessels :  on  ac- 
count of  its  smoothness,  brig  itness,  and 
unctuous  quality,  it  has  been  celebrated 
as  a  cosmetic;  and  various  unsuccessful 
experiments  have  been  made,  with  a  view 
to  extract  from  it  oils,  salts,  and  other 
supposed  ingredients.. ..When  combined 
with  alkaline  salts,  it  is  fusible  in  a  strong 
heat,  and  forms  a  transparent,  handsome, 
greenish-yellow  glass  :  if  equal  portions 
of  talc  and  of  chalk  be  melted  together 
with  one-fourth  part  of  borax,  the  mix- 
tuie  will  produce  a  hue  pellucid  greenish 
glass,  wiiicii  is  of  considerable  lustre  and 
hai  dness. 

T  A  LI  .OW.-We  do  not  know  of  any  ex- 
perhrs<rr.».s,  which  ascertain  a  chemical  dif- 
fer ce  between  this  concrete  animal  fat, 
which  is  chiefly  taken  from  the  intestines 
of  animals,  and  other  fat  oils  of  the  same 
nature.  The  most  valuable  property  of 
tallow  is,  the  considerable  heat  it  requires 
to  fuse  it,  which  is  commonly  distinguish- 
ed by  the  term  hardness.  The  quantity 
of  soot  and  fetid  exhalation  emitted  from 
the  various  kinds  of  tallow  candles 
brought  to  market,  also  forms  a  distin- 
guishing characteristic  in  the  use  of  this 
article,  and  is  accompanied  with  notable 
variations  in  the  quantities  of  light  afford- 
ed by  each. 

It  is  an  object  of  no  small  importance 
to  purify  or  improve  tallow.  The  tallow- 
chandlers  clear  it  of  fibrous  matter  and 
other  gross  impurities  by  careful  melting, 
straining,  and  the  like  mechanical  manage- 
ment. It  is  said  also,  that  they  improve 
its  whiteness  by  the  addition  of  alum,  the 
efficacy  of  which  we  are  much  disposed 
to  doubt.  It  is  thought,  too,  that  long 
keeping,  and  the  action  of  the  external 
air,  improve  its  hardness ;  but  these  slow 
operations  are  ill  calculated  for  a  manu- 
factory, in  which  the  greatest  part  of  the 
capital  is  vested  in  the  raw  material, 
and  very  little  in  the  manufacturing 
process  :  and  if  they  increase  the  hard- 
ness of  the  tallow,  they  injure  the  colour, 
and  candles  kept  too  long  do  not  burn  so 
well. 

The  melting  of  tallow  is  done  by  chop- 
ping the  fat  as  it  is  taken  from  oxen  and 
sheep,  and  then  boiling  it  for  some  time  in 
a  large  copper,  and  when  the  tallow  is  ex- 
tracted by  the  process  of  fire,  the  remain- 
der is  sujected  to  the  operation  of  a  strong 
iron  press,  and  the  cake  that  is  left  after 
the  tallow  is  expressed  from  it  is  called 
a  greave. 

The  oxigenized  muriatic  acid  produces 


a  state  in  tallow,  which  is  somewhat  near« 
er  to  that  of  w  ax  than  before,  and  a  thin 
stratum  of  tallow  exposed  upon  an  ex- 
tended surface  of  water  becomes  likewise 
harder ;  but  the  indications  these  pro- 
cesses might  afford  to  the  manufacturer, 
have  noi  veibeen  applied  to  any  extended 
purposes  of  utility. 

TALLOW-CHANDLERY,  or,  more  pro- 
perly, candie-making,  is  a  profession  which 
is  partly  chemical  and  partly  mechanical. 
After  preparing  the  wick,  which  is  done 
agreeably  to  a  rule  established,  the  next 
operation  is  the  covering  of  it  with  tal- 
low. 

The  tallow  is  first  melted  in  a  large 
copper,  and  after  it  is  well  skimmed  and 
refined,  it  is  brought  into  a  vessel  called  a 
mould,  in  which  the  cottons  are  dipped. 
The  workman  holds  three  of  these 
broaches  between  his  fingers,  and  im- 
merses the  cottons  into  the  mould  :  they 
are  then  hung  on  a  frame,  for  the  purpose, 
till  they  become  cold  and  hard;  during 
which  others  are  dipped  When  cold, 
they  are  dipped  a  second  and  a  third 
time,  and  so  on  till  the  candles  are  of  the 
proper  size. 

During  the  operation,  the  tallow  is  stir- 
red from  time  to  time,  and  the  mould  sup- 
plied with  fresh  tallow,  which  is  kept  to 
the  proper  heat  by  means  of  a  fire  un- 
der it. 

Such  was  the  laborious  method  uni- 
vesally  adopted  in  making  common  can- 
dles, till  within  these  fifteen  or  twenty 
years,  when  an  invention  was  introduced, 
and  may  be  thus  described  : — In  a  beam 
three  pulleys  are  let  in  ;  round  these,  pro- 
per sized  ropes  run,  and  are  fixed  to  a 
machine  on  which  six  broaches  are  pla- 
ced. In  the  scale  are  weights  sufficient 
to  draw  up  the  broaches :  these  are  in- 
creased as  the  candles  become  larger  and 
heavier.  The  workman,  by  means  of  this 
very  simple  and  excellent  contrivance,  has 
only  to  guide  the  candles,  and  not  to  sup- 
port the  weight  of  them  between  his  fin- 
gers. 

Mould  candles,  as  the  name  express- 
es, are  cast  in  a  mould.  The  frame  is 
of  wood,  and  the  several  moulds  are 
hollow  metal  cylinders,  generally  made  of 
pewter,  of  the  diameter  and  length  of  the 
candle  wanted,  &c.  Rush-lights  have  a 
split  rush  for  the  wick. 

Professor  Medicus  has  given  the  fol- 
lowing observations  on  the  method  of  pre  • 
paring  tallow  candles  with  wooden  wicks. 

For  several  years  past  tallow  candles 
with  wooden  wicks  have  been  prepared, 
in  large  quantities,  by  the  candle-makers 
at  Munich,  and  much  used  in  that  neigh 
bourhood    I  have  burnt  them  during  the 


TAL 


TAL 


whole  winter,  and  never  wish  to  use  any 
other  kind,  as  they  are  attended  with  se- 
veral advantages  which  common  tallow 
candles  do  not  possess.  They  afford 
about  the  same  quantity  of  light  as  a  wax 
candle ;  burn  also  with  great  steadiness 
and  uniformity,  and  never  crackle  or  run. 
The  candle-makers  here  keep  the  method 
of  preparing  these  candles  as  secret  as 
they  can  ;  but  I  shall  communicate  to  the 
public  what  I  have  been  able  to  learn  re- 
specting the  process. 

The  only  difference  between  these  can- 
dles and  the  common  tallow  candles,  is, 
that  the  ground-work  of  the  wick  con- 
sists of  a  very  thin  slip  of  wood,  bound 
round  to  a  considerable  thickness  with 
very  fine  unspun  cotton  ;  but  in  such  a 
manner  that  the  size  of  the  wick  does  not 
much  exceed  that  of  the  wick  of  a  common 
candle.  The  cotton  is  sometimes  wound 
round  the  wick  by  the  hand  ;  but  in  gene- 
ral it  is  done  by  means  of  a  reel,  which  1  have 
not  yet  been  able  to  see.  The  thin  slips 
of  wood  are  furnished  to  the  candle-ma- 
kers by  the  country  people,  and,  if  we  may 
judge  from  their  appearance,  are  cut  into 
the  proper  form  by  means  of  a  knife, 
without  the  application  of  any  machine. 
They  are  for  the  most  part  somewhat 
square,  and  not  completely  rounded. 
The  candle-makers  often  prepare  these 
slips  of  wood  also  themselves,  when  they 
have  none  ready  by  them,  and  for  that 
purpose  use  pine,  willow,  and  other  kinds 
of  wood,  though  they  commonly  employ 
lir.  For  making  these  candles  it  is  ne- 
cessary to  have  the  purest  tallow  :  a 
pound  will  be  sufficient  to  make  six  or  se- 
ven, which  cost  twenty-five  kreutzers. 
The  price  of  common  moulded  candles 
with  cotton  wicks  is  twenty-two  kreut- 
zers ;  but  as  the  former  burn  much  lon- 
ger, they  are  on  the  whole  cheaper. 

Another  method  of  making  the  wicks 
is  as  follows  :  Take  shoots  of  the  pine  tree 
a  year  old,  scrape  off  the  bark,  and  when 
they  are  become  perfectly  dry  scrape 
them  again  all  round  till  they  are  reduced 
to  the  size  of  a  small  straw.  When  the 
above  wood  cannot  be  procured,  well 
dried  common  fir  twigs  of  a  year  old,  and 
of  the  same  strength,  may  be  prepared  in 
the  like  manner.  These  rods  are  then  to 
be  rubbed  over  with  wax  or  tallow,  till 
they  are  covered  with  a  thin  coating  of  ei- 
ther of  these  substances  ;  after  which 
they  must  be  rolled  on  a  smooth  table  in 
very  fine  carded  cotton,  drawn  out  to 
about  the  length  of  the  rod  or  candle- 
mould.  Care,  however,  must  be  taken 
that  by  this  rolling  no  inequalities  may 
arise  on  the  rod,  and  that  the  cotton  may 
be  every  where  of  equal  thickness,  though 


at  the  upper  part  a  little  more  of  it,  may 
be  applied.  After  this  preparation,  the 
wick  will  have  acquired  the  size  of  the 
barrel  of  a  small  quill ;  and  the  more  ac- 
curately the  size  of  the  wick  is  propor- 
tioned to  that  of  the  candle  mould,  the 
candles  will  burn  so  much  the  better, 
clearer,  and  longer,  as  will  soon  be  found 
by  a  little  experience :  these  wicks  are 
then  to  be  placed  very  exactly  in  the 
middle  of  the  mould,  and  retained  in  that 
position,  and  good  tallow,  fresh  if  possi 
ble,  previously  melted  with  a  little  water, 
must  be  poured  round  them;  but  even 
old  and  rancid  tallow  will  not  run,  if  the 
wicks  be  properly  made. 

These  candles,  besides  burning  longer 
than  the  common  ones,  have  also  this  ad- 
vantage, that  they  do  not  flare,  and  that 
they  are  less  prejudicial  to  the  eyes  ot 
those  who  are  accustomed  to  read  or 
write  at  night.  It  is,  however,  to  be  ob- 
served, that  a  pair  of  sharp  scissors  must 
be  employed  for  snuffing  them,  and  that 
in  performing  that  operation  care  must  be 
taken  not  to  break  or  derange  the  wick. 

The  following-  observations  on  the  the- 
ory of  combustion,  may  be  noticed  in  this 
place. 

The  production  of  light  by  inflamma- 
tion is  an  object  of  great  importance  to 
society  at  large,  as  well  as  to  the  che- 
mist.   It  appears  to  arise  immediately 
from  the  strong  ignition  of  a  body  while 
rapidly  decomposing.    Most  solid  bodies 
in  combustion  are  kept,  partly  from  a 
want  of  the  access  of  air,  and  partly  from 
the  vicinity  of  conducting  bodies,  at  a  low 
degree  of  ignition.     But  when  vapours 
rapidly  escape  into  the  air,  it  may,  and 
does  frequently  happen,  that  the  combus- 
tion, instead  of  being  carried  on  at  the 
surface  of  the  mass,  penetrates  at  a  con- 
siderable depth  within,  and  from  this,  as 
well  as  from  the  imperfect  conducting 
power  of  the  surrounding  air,  a  white 
heat,  or  very  strong  ignition,  is  produced. 
The  effect  of  lamps  and  candles  depends 
upon  these  considerations.    A  combusti- 
ble fluid,  most  commonly  of  the  nature  of 
fat  oil,  is  put  in  a  situation  to  be  absorbed 
between  the  filaments  of  cotton,  linen, 
fine  wire,  or  asbestos.    The  exi.'-emity  of 
this  fibrous  substance,  called  the  wick,  is 
then  considerably  heated    The  oil  evapo- 
rates, and  its  vapour  takes  fire.  In  this  si- 
tuation the  wick,  being  enveloped  with 
flame,  is  kept  at  such  a  temperature,  that 
the  oil  continually-  boils,  is  evaporated, 
burns,  and  by  these  means  keeps  up  a 
constant  flame.    Much  of  the  perfection 
of  this  experiment  depends  on  the  nature, 
quantities,  and  figure,  of  the  materials 
made  use  of.    If  the  wick  be  too  large,  it 


TAL 


TAL 


Hrftl  supply  a  greater  quantity  of  the  fluid 
than  can  be  well  decomposed.    Its  evapo- 
ration will  therefre  diminish  the  temper- 
ature, and  consequently  the  light,  and  af- 
ford a  fuliginous  column,  which  will  pass 
through  the  centre  of  the  flame,  and  fly  off 
in  the  form  of  smoke.  The  magnitude  of  the 
wick  may,  from  time  to  time,  in  candles,  be 
reduced,  as  to  length,  by  snuffing;  but  this 
operation  will  not  remedy  the  evils  which 
"arise  from  too  great  a  diameter.    If  the 
oil  be  not  sufficiently  combustible,  the  ig- 
nition will  be  but  moderate,  and  the 
flame  yellow  ;  and  the  same  effect  will  be 
produced,  if  the  air  be  not  sufficiently 
pure  and  abundant.    An  experiment  to 
this  effect  may  be  made  by  including  the 
flame  of  a  small  candle  or  lamp  in  a  glass 
tube  of  about  one  inch  in  diameter,  stand- 
ing on  the  surface  of  a  table.    The  air 
which  passes  between  the  glass  and  the 
table,  will  be  sufficient  to  maintain  a  very 
bright  flame  ;  but  if  a  metallic  covering, 
perforated  with  a  hole  of  about  a  quarter 
of  an  inch  diameter,  be  laid  upon  the  up- 
per orifice  of  the  tube,  the  combination 
will  be  so  far  impeded,  that  the  flame  will 
be  perceptibly  yellower.    The  hole  may 
then  be  more  or  less  closed  at  pleasure 
by  sliding  a  small  piece  of  metal,  for  ex- 
ample, a  shilling,  over  it    The  conse- 
quence will  be,  that  the  flame,  will  become 
more  and  more  yellow,  will  at  length 
emit  smoke,  and,  if  the  hole  be  entirely 
closed,  extinction  will  follow. 

The  smell  arising  from  the  volatile  parts, 
which  pass  off'  not  well  consumed  from  a 
lamp  or  candle,  must  be  different  accord- 
ing to  the  nature  of  those  parts.  This  de- 
pends chiefly  on  the  oil,  but  in  some  mea- 
sure upon  the  wick.  When  a  candle  with 
a  cotton  wick  is  blown  out,  the  smell  is 
considerably  more  offensive,  than  if  the 
wick  be  of  linen,  or  of  rush  ;  but  less  of- 
fensive than  if  the  supply  of  the  combus- 
tion had  been  oil.  Whenever  a  candle  or 
lamp  is  removed,  the  combustion  is  in 
some  measure  impeded  by  the  stream  of 
cold  air,  against  which  it  strikes.  Smoke 
is  accordingly  emitted  from  its  anterior 
side,  and  the  peculiar  smell  is  perceived. 
From  this  imperfection,  lamps  are  much 
less  adapted  to  be  carried  from  place  to 
place  than  candles. 

From  the  necessity  of  the  access  of  air, 
there  will  be  more  light  produced  from  a 
lamp  with  a  number  of  small  wicks,  than 
with  one  large  one,  or  from  a  number  of 
small  candles,  than  the  same  quantity  of 
tallow  used  to  make  a  single  large  one. 
Iu  the  lamp  of  Argand,  the  wick  consists 
of  a  web  or  cloth  in  the  form  of  a  pipe  or 
tube,  the  longitudinal  fibres  of  which  are 
thicker  than  the  circular  ones.  This  is 
VOI.  II. 


passed  by  a  suitable  contrivance  into  a 
cylindrical  cavity,  which  contains  the  oil ; 
and  there  are  other  precautions  in  the 
construction  of  the  apparatus,  by  which 
the  oil  is  regularly  supplied,  the  access  of 
air  is  duly  permitted,  as  well  within  as 
without  the  circle  formed  by  the  upper 
edge  of  this  cylindrical  wick,  and  this 
edge  can  be  raised  or  lowered  at  pleasure. 
Hence  the  possessor  has  it  in  his  power 
to  regulate  the  surface  of  the  wick,  so 
that  the  greatest  flame  consistent  with 
perfect  combustion  may  be  produced; 
and  the  steadiness  of  the  flame  is  secured 
by  a  glass  shade  or  tube,  which  surrounds 
it,  and  in  a  certain  degree  accelerates  the 
current  of  air. 

In  the  illumination  by  candles,  where 
the  fused  matter  is  contained  in  a  cup  or 
cavity  of  the  matter  not  yet  fused,  it  is  of 
some  consequence,  whether  the  substance 
be  fusible  at  a  high  or  low  temperature. 
The  difference  between  wax  and  tallow 
candles  arises  from  this  property.  Wax 
being  less  fusible,  will  admit  of  a  thinner 
wick,  and  needs  no  snuffing;  but  in  a  tal- 
low candle  it  is  absolutely  necessary  to 
have  a  large  wick,  capable  of  taking*  up 
the  tallow  as  it  melts. 

The  difference  of  effect  in  illumination 
between  a  thick  and  a  thin  wick  cannot 
be  better  shown,  than  by  remarking  the 
appearances  produced  by  both.    When  a 
candle  with  a  thick  wick  is  first  lighted, 
and  the  wick  emitted  short,  the  flame  is 
perfect  and  luminous,  unless  its  diameter 
be  very  great ;  in  which  last  case,  there 
is  an  opake  part  in  the  middle,  where  the 
combustion  is  impeded  for  want  of  air. 
As  the  wick  becomes  longer,  the  space 
between  its  upper  extremity  and  the  apex 
of  the  flame  is  diminished ;  and  conse- 
quently the  oil,  which  issues  from  that 
extremity,  having  a  less  space  of  ignition 
to  pass  through,  is  less  completely  burn- 
ed, and  passes  oft'  partly  in  smoke.  This 
evil  continues  to  increase,  until  at  length 
the  upper  extremity  of  the  wick  projects  * 
beyond  the  flame,  and  forms  a  support  for 
an  accumulation  of  soot,  which  is  afford- 
ed by  the  imperfect  combustion.    A  can- 
dle in  this  situation  affords  scarcely  one 
tenth  of  the  light,  which  the  due  combus- 
tion of  its  materials  would  produce ;  and 
tallow  candles,  on  this  account,  require 
continual  snuffing.    But  on  the  contrary, 
if  we  consider  the  wax-candle,  we  find, 
that  as  its  wick  lengthens,  the  light  in- 
deed becomes  less,  and  the  cup  becomes 
filled  with  melted  wax.    The  wick,  how- 
ever, being  thin  and  flexible,  does  not 
long  occupy  its  place  in  the  centre  of  the 
flame ;  neither  does  it,  when  there,  en- 
large the  diameter  of  the  flame,  so  as  to 
3  L 


TAN 


TAX 


prevent  the  access  of  air  to  its  internal 
part.  When  its  length  is  too  great  for 
the  vertical  position,  it  bends  on  one  side ; 
and  its  extremity,  coming  in  contact  with 
the  air,  is  burned  to  ashes,  excepting  such 
a  portion  as  is  defended  by  the  continual 
afflux  of  melted  w.ix,  which  is  volatilized 
and  completely  burned  by  the  surround- 
ing flame.  We  see,  therefore,  that  the 
difficult  fusibility  of  wax  renders  it  prac- 
ticable to  burn  a"  large  quantity  of  fluid  by 
means  of  a  small  wick;  and  that  this 
small  wick,  by  turning  on  one  side  in 
consequence  of  its  flexibility,  performs 
the  operation  of  snuffing  upon  itself,  in  a 
much  more  accurate  manner  than  it  can 
ever  be  performed  mechanically.  Mr. 
Walker  has  suggested  an  ingenious  con- 
trivance to  effect  this  in  tallow  candles. 
It  consists  in  placing  the  candle  in  such  a 
position,  as  to  be  inclined  in  an  angle  of 
about  30°  from  the  perpendicular  ;  by 
which  means  the  wick  will  come  out  at 
the  side  of  the  flame  when  it  is  long 
enough  to  require  snuffing,  and  there, 
burn  to  ashes.  The  light  thus  produced 
remaining  nearly  equable  at  all  times, 
must  be  less  injurious  to  the  eyes. 

Mr.  Henry  made  some  experiments  on 
the  light  afforded  by  the  combination  of 
different  gasses,  and  found,  that  it  was 
apparently  in  the  ratio  of  the  oxigen  that 
entered  into  combination  with  the  hydro- 
gen they  contained.  Thus  100  parts  of 
pure  hydrogen  gas  required  from  50  to  54 
of  oxigen :  100  of  gas  from  oak  42 :  from 
moist  charcoal,  and  from  dried  peat,  each 
50  :  from  lamp  oil  136 :  from  coal  140 : 
from  wax  166:  pure  olifiant  gas  210. 
Tallow  is  nearly  on  a  par  with  oil.  The 
production  of  light  from  the  first  four  was 
so  trifling,  that  they  did  not  appear  appli- 
cable to  economical  purposes. 

TALLOW  (MINERAL).  See  Bitu- 
men. 

TAMARINDS.  The  fruit  of  the  ta- 
marindus  indica  L.  It  is  a  pod  resem- 
bling a  bean-pod,  including  several  hard 
seeds,  together  with  a  dark  coloured  vis- 
cid pulp,  of  a  pleasant  acid  taste  ;  the  East 
India  tamarinds  are  longer  than  the  West 
India  sort ;  the  former  containing  six  or 
seven  seeds  each,  the  latter  rarely  above 
three  or  four. 

TAN  or  TANNIN.  7 

TANNING,  {the  Attof)  5 

The  general  properties  of  tannin,  parti- 
cularly as  connected  with  the  art  of  tan- 
ning, wider  the  articles  Leather  and 
Gelatin;  and  the  properties  of  the 
compound  of  tannin,  gallic  acid,  and  ex- 
tract, with  various  earthy  and  other  salts, 
which  exists  in  the  infusion  of  astringent 
Vegetables,  have  been  given  under  the  ar- 


ticle Galls,  to  all  of  which  we  must  re- 
fer the  reader.  It  will  be  proper  however, 
in  this  place,  slightly  to  recapitulate  the 
general  properties  of  tannin,  the  methods 
by  which  chemists  have  endeavoured  to 
obtain  it  pure,  and  those  by  which  its  re- 
lative proportion  to  the  other  contents  of 
astringent  infusions,  have  been  estimated. 
We  shall  also  add  an  account  of  the  late 
experiments,  by  which  Mr.  Hatchett  has 
produced  a  substance,  closely  resembling 
tannin. 

Mr.  Biggins  has  made  a  great  many  ex- 
periments upon  the  quantity  of  tanning 
principle  in  various  barks,  from  which  he 
has  constructed  the  following  table. 

Tanning  principle  (in  gvs.) 
from  halt  a  pint  of  infu 
sion,  and  an  ounce  of  so- 
lution of  glue. 
Bark  of  elm  -  -  28 
oak,  cut  in  winter  30 
horse-chesnut  -  30 
beech  -  -  Si 
willow  (boughs)  31 
elder  -  -  41 
plum-tree  -  58 
willow  (trunk)  -  52 
sycamore  53 
birch  54 
cherry-tree  -  59 
sallow  -  -  59 
mountain-ash  -  60 
poplar  76 
hazel  -  -  79 
ash  -  -  82 
Spanish  chesnut  98 
smooth  oak  -  10 1 
oak,  cut  in  spring  10S 
Huntingdon  or  Lei- 
cestershire willow  109 
sumach        -       -  158 

The  substance  called  tan  or  tannin,  is 
distinguished  by  its  strong  astringent 
taste,  by  a  peculiar  smell,  by  forming  im- 
mediately with  a  solution  of  gelatin,  a 
whitish  compound  insoluble  in  water  and 
alcohol,  and  by  uniting  to  animal  skin, 
(which  is  chiefly  gelatin  in  a  condensed 
state,)  immersed  in  it  rendering  it  harder, 
less  impervious  to  water,  and  no  longer 
susceptible  of  putrefaction.  These  are 
the  peculiar  advantages  procured  by  the 
art  of  tanning,  which  has  bee.i  described 
under  the  article  Leather. 

Tannin  is  one  of  the  immediate  prin- 
ciples of  vegetables,  was  first  distinguish- 
ed by  Scguin  from  the  gallic  acid,  with 
which  it  lias  been  confounded  under  the 
name  of  the  astringent  principle.  He  gave 
it  the  name  of  tannin,  from  its  use  in  the 
tanning  of  leather  ;  which  it  effects  by  its 
characteristic  property,  that  of  forming 


TAN 


TAN 


with  gelatin,  a  tough  and  insoluble  mat- 
tor. 

Proust  who  has  made  many  researches 
on  tannin,  gives  the  following  method  of 
obtaining  it,  from  the  decoction  of  gulls. 

Pour  into  the  decoction  a  solution  of 
mnriat  of  tin,  which  will  give  a  copious 
yellow  precipitate.  Separate  this  by  fil- 
tration, and  when  well  washed,  it  will  con- 
sist (as  he  asserts)  of  all  the  tannin  united 
to  the  oxyd  of  tin.  To  separate  these 
two,  diffuse  the  precipitate  in  water,  and 
pass  a  current  of  sulphuretted  hydrogen 
gas,  through  the  liquid.  By  degrees  an 
insoluble  hydro-sulphuret  of  tin  will  be 
precipitated,  and  the  tannin  now  separat- 
ed from  the  oxyd,  will  resume  its  solu- 
bility and  dissolve  in  the  fluid,  giving  it 
the  acerb  taste,  and  peculiar  smell  of  the 
decoction  of  galls,  after  the  excess  of  sul- 
phuretted hydrogen  has  been  expelled 
by  boiling.  This  solution  lathers  like 
soap-water  on  agitation,  and  when  con- 
centrated by  boiling,  it  deposits  a  brown 
powder  on  cooling,  wliich  is  re-dissolved 
by  heat.  When  evaporated  to  dryness, 
it  leaves  a  dry,  brown,  friable,  resinous 
looking  mass,  like  aloes,  which  does  not 
deliquesce,  has  an  intensely  acerb  taste, 
•e-dissolves  in  water  and  alcohol,  and  then 
gives  an  immediate  precipitate  with  the 
solutions  of  gelatin,  which  is  the  most 
characteristic  property  of  tannin. 

The  clear  liquor  that  remains  in  the 
first  part  of  this  process,  (that  is  after 
adding  muriat  of  tin  to  the  decoction  of 
galls,)  contains  gallic  acid,  and  muriat  of 
tin. 

Another  method  proposed  by  the  same 
chemist  of  obtaining,  what  he  conceived 
to  he  pure  tannin,  was  to  pour  into  an  in- 
fusion of  galls,  a  solution  of  potash  tho- 
roughly saturated  with  carbonic  acid, 
such  as  the  crystallized  carbonate  of  pot- 
ash is,  which  produces  a  yellowish  white 
curdy  precipitate,  of  the  substance  in 

3uestion.  The  liquors  should  not  be  too 
ilute,  nor  the  precipitate  washed  with 
too  much  water,  as  it  is  soluble  in  water, 
though  sparingly.  This  precipitate  dries 
slowly,  but  when  spread  over  any  smooth 
surface,  in  thin  layers,  and  stoved,  it  be- 
comes a  brittle  resinous  yellow  mass — 
This  substance  distilled  per  se,  gives  a 
saline  liquor,  with  an  ammoniacal  smell, 
which  blackens  the  solutions  of  iron,  and 
also  a  little  thick  butyraccous  oil,  and 
leaves  a  bulky  coal. 

Mr,  Davy  however,  on  repeating  these 
experiments,  found  that  this  precipitate, 
did  not  exhibit  the  properties  of  pure  tan- 
nin, as  it  wants  the  peculiar  astringent 
taste,  is  but  soluble  in  cold  water  and  al- 


cohol, and  the  solution  is  not  precipitated 
by  gelatin,  till  it  is  saturated  with  an  acid. 
It  also  gives  by  incineration,  a  considera- 
ble quantity  of  carbonat  of  potash,  and 
some  carbonate  of  lime.  It  also  affords 
gallic  acid  by  distillation. 

From  these  and  other  facts,  it  appears 
that  this  precipitate  is  not  pure  tannin, 
but  is  a  very  compounded  substance,  con- 
taining tannin,  gallic  acid,  alkali  and  lime, 
and  perhaps  extract. 

From  all  that  has  been  done  on  this 
subject,  it  appears  therefore  that  we  can- 
not be  certain,  that  we  have  ever  obtain- 
ed pure  tannin,  free  from  all  other  admix- 
ture ;  and  it  is  equally  certain,  that  none 
of  these  methods,  can  extract  the  whole 
of  this  substance  from  vegetable  infusions; 
so  that  it  is  still  the  best  method,  in  ex- 
periments, where  the  quantity  of  tan  alone 
is  required,  to  make  use  of  the  infusion 
of  animal  gelatin,  and  estimate  the  quan- 
tity of  tan,  from  the  weight  of  the  com- 
pound of  tan  and  gelatin,  thus  produc- 
ed. 

With  proper  precautions,  the  gelatin 
only  separates  the  tannin  from  the  vege- 
table infusions ;  and  this  compound  ap- 
pears tolerably  uniform  in  its  nature,  and 
in  the  proportion  of  its  constituent  parts, 
though  we  have  not  been  able  to  separate 
them,  without  destroying  the  characteris- 
tic properties  of  each. 

In  applying  the  solution  of  gelatin  to 
infusions  containing  tannin,  several  cir- 
cumstances must  be  noted.  It  appears, 
in  the  first  place,  that  the  mere  dilution 
of  the  liquids,  influences  the  quantity  of 
precipitate,  this  being  the  greatest,  in  pro- 
portion as  the  solution  of  tannin  is  most 
concentrated. 

The  proportion  of  isinglass  (fish  gtue)and 
water,employed  by  Mr.Davy,  are  6  grains 
of  the  former  to  an  ounce  of  liquid,  which 
is  nearly  as  strong  as  can  be  made  at  a 
moderate  temperature,  without  being  in- 
conveniently stiff"  and  gelatinous.  Care 
must  be  taken,  not  to  add  an  over  propor- 
tion of  gelatin,  to  the  vegetable  infusion, 
for  when  this  happens,  it  appears  that 
some  of  the  compound  is  dissolved  in  the 
mixture,  as  less  of  it  is  precipitated.  Pro- 
bably therefore  gelatin  unites  with  tannin, 
in  different  proportions,  and  the  com 
pound  is  only  insoluble,  when  the  gelatin 
is  in  the  inferior  proportion.  The  preci- 
pitate should  always  be  dried  at  a  tolera- 
bly uniform  temperature,  somewhat  high- 
er than  that  of  the  atmosphere.  This  pre 
cipitate  is  composed,  according  to  Mr 
Davy,  on  an  average,  of  about  54  per  cent, 
of  gelatin,  and  46  of  tannin.  There  is 
much  more  tannin,  however,  in  this  cam- 


TAN 


TAN 


pound,  than  in  tanned  leather,  or  skin  sa- 
turated with  tannin,  though  the  constitu- 
ent parts  are  nearly  the  same. 

It  remains  to  mention  a  very  curious 
production  of  tannin,  by  artificial  means, 
from  substances  which  do  not  naturally 
contain  a  particle  of  it,  lately  discovered 
by  Mr,  Hatchett,  and  partially  noticed 
in  this  volume,  under  the  article  Resin. 

The  ingenious  author  wus  led  to  the 
discovery,  by  pursuing  his  former  expe- 
riments on  bitumens  and  bovey  coal,  and 
in  particular,  on  their  habitudes  with  ni- 
tric acid.  When  a  pure  resin  is  digested 
with  this  acid,  it  is  converted  into  an 
orange-coloured  viscid  substance,  which 
at  first  separates,  but  by  a  further  affu- 
sion of  acid,  is  rendered  soluble  in  water 
and  alcohol. 

On  the  other  hand,  when  bitumen  is 
treated  in  this  manner,  the  first  effect  of 
the  acid,  is  to  separate  this  orange -yellow 
substance,  and  at  the  same  time  to  pro- 
duce a  very  dark  brown  solution.  Now 
as  the  bitumens  were  shown  by  previous 
experiments,  to  consist  of  a  resin,  holding 
a  portion  of  uncombined  carbon,  Mr.  H. 
conceived  that  a  separation  of  these  two 
substances,  w^as  effected  by  the  acid,  and 
that  the  brown  solution  contained  only 
the  uncombined  carbon,  dissolved  in  ni- 
tric acid,  whilst  the  orange-coloured  mass 
was  furnished  by  the  resin.  This  was 
confirmed  by  treating  in  the  same  way, 
amber,  asphaltum,  different  species  of  pit- 
coal,  and  lastly  pure  charcoal,  all  of  which 
yielded  the  brown  solution  in  abundance, 
particularly  the  charcoal,  but  only  those 
substances  that  contained  bitumen,  depo- 
sited any  of  the  orange  coloured  mass. — 
The  charcoal  therefore  yielded  none  of 
this  latter,  but  dissolved  completely  in 
the  acid,  making  a  dark  reddish-brown 
liquid.  This  liquid  was  slowly  evaporat- 
ed to  dryness,  and  left  a  brown  glossy 
substance,  with  a  resinous  fracture. 

In  addition  to  the  remarks  heretofore 
made,  on  the  art  of  tanning,  the  following 
additional  observations  of  an  author  may 
be  useful. 

All  the  operations  performed  upon 
skins,  preliminary  to  tanning  them,  con- 
sist in  separating  such  matters,  as  are  of 
a  different  nature,  from  the  epidermis  and 
the  fibres,  which  constitute  the  skin,  in 
order  that  the  astringent  principle  may 
afterwards  be  combined,  with  these  ani- 
mal fibres.  He  next  examines  the  differ- 
ent processes  of  the  art  of  tanning,  ana- 
lyses their  advantages  and  imperfections, 
and  has  succeeded  in  simplifying  and 
abridging  them,  and  by  these  means  ac- 
celerating the  return  of  capital,  of  which 
the  investment  constitutes  a  !*arge  part  of* 


the  price  of  leather.  With  this  view,  his 
inquiries  were  directed  to  ascertain,  what 
degree  of  heat  is  sufficient  to  extract  the 
animal  jelly,  and  also  at  what  temperature 
the  fibrous"  texture  of  the  skin,  begins  to 
suffer  alteration. 

He  ascertained,  that  the  heat  proper  to 
dissolve  the  animal  jelly  commences  at 
140°  Fahr.  and  that  the  fibrous  texture  is 
capable  of  sustaining  a  degree  of  heat 
beyond  167°  Fahr.  without  undergoing 
any  alteration,  in  places  where  the  mean 
temperature  of  the  barometer,  is  twenty- 
six  inches  and  four  lines,  suppose  French 
measure. 

In  consequence  of  his  researches  and 
observations,  the  author  proposes  to  re- 
duce the  practice  of  the  art  of  tanning  to 
the  following  particulars  : 

1.  The  skins  are  to  be  kept  separately 
immersed  in  running  water,  for  a  time 
sufficient  to  extract  the  lymph  or  serum. 
This  period  is  easily  ascertained,  by  put- 
ting  a  piece  of  the  skin  into  a  small  quan- 
tity of  water,  and  gradually  heating  it. — 
If  it  contains  serum,  this  matter  will  be 
first  extracted,  and  afterwards  coagulated 
in  the  form  of  scum  on  the  surface.  If 
therefore  no  scum  appear,  the  skins  may 
be  considered  as  purified,  from  lymphatic 
matter. 

2.  These  washed  and  rinced  skins  are 
then  to  be  transferred  into  boilers,  pro- 
perly adapted  for  the  purpose :  water  is 
then  to  be  added,  and  heat  applied,  so 
that  the  temperature  of  the  water,  may 
not  exceed  60°  Fahrenheit.  The  skins 
are  to  remain  in  this  situation  for  a* 
hour. 

3.  The  skins  are  then  to  be  taken  out, 
and  worked  in  the  usual  manner,  to  clear 
them  of  their  impurities. 

4.  After  this  process  they  are  again  to 
be  placed  in  the  boiler,  which  must  be  so 
disposed,  that  a  constant  stream  of  water 
at  the  temperature  of  167  degrees  of 
Fahrenheit,  shall  enter  by  one  cock,  and 
pass  off  by  another,  on  the  opposite  side 
beneath. 

5.  The  skins  are  to  remain  in  this  situ- 
ation, until  the  water  that  comes  off,  ex- 
hibits no  vestige  of  animal  jelly.  This  is 
easily  ascertained,  by  evaporating  a  small 
quantity. 

6.  The  skins  are  then  to  be  taken  out, 
and  cleared  in  the  usual  manner  of  the 
cellular  membrane,  and  fleshy  parts. 

7.  Lastly,  they  are  to  be  washed  _  in 
running  stream,  and  re-placed  in  a  boiler, 
similar  to  that  just  mentioned,  which  is 
to  be  filled  with  the  saturated  decoction 
of  tan,  or  oak  bark.  The  same  degree 
of  heat  is  to  be  applied,  as  in  the  preced- 
ing operation,  and  tile  skins  are  to  remain 

L 


TAN 


TAU 


Until  they  are  perfectly  tanned.  Fresh 
decoction  of  tan  must  be  substituted  from 
time  to  time,  in  the  room  of  that  which  is 
exhausted.  The  exhausted  state  is  shown 
by  its  hot  having  power  to  afford  a  black, 
When  a  few  drops  of  solution  of  sulphat. 
of  iron  are  added. 

TANTAL1UM. — This  is  a  new  metal, 
discovered  by  Mr.  Eekeburg  of  Sweden, 
as  he  was  examining  a  fossil  containing 
yttria,  with  a  view  to  ascertain  the  differ- 
ence or  identity  of  this  earth  and  glucine. 
Beside  this  fossil,  which  he  calls  yttrotan- 
talite,  he  has  found  another  ore  of tanta- 
lium,  in  which  this  metal  is  mixed  with 
iron  and  manganese,  and  which  he  calls 
tantalitei 

Tantalite  is  in  detached  crystals,  of  the 
size  of  a  nut,  approaching  the  octaedral 
form.  It  contains  particles  of  feldspar 
and  mica.  Its  surface  is  even,  polished, 
aijd  blackish.  Fracture  compact,  of  a  me- 
tallic  brilliancy,  and  not  alike  in  colour 
all  through,  varying  from  a  grayish  blue 
to  the  black  of  iron.  Powdered,  it  is  of  a 
blackish  gray,  approaching  to  brown.  It 
gives  sparks  with  steel.  Specific  gravity 
7.953.  Its  gangue  is  composed  of  white 
quartz  and  mica,  with  veins  of  red  feld- 
spar. These  crystals  had  been  consider- 
ed as  a  variety  of  the  garnet-shaped  tin 
ore. 

The  yttrotantalite  was  found  in  the 
same  place  and  gangue  as  gadolinite  ;  in 
small  nodules,  not  so  large  as  a  nut,  thin- 
ly encrusted  with  feldspar.  Its  fracture 
is  granulated,  of  the  black  colour  of  iron, 
with  a  metallic  brilliancy.  When  in  pow- 
der it  is  grayish.  It  is  not  attracted  by 
the  magnet.  It  may  be  scraped  with  a 
knife,  though  with  difficulty.  Specific 
gravity  5.13;  though  no  doubt  it  would 
be  more,  if  totally  free  from  feldspar. 

Tantalium  is  characterized  by  its  inso- 
lubility in  all  the  acids.  The  only  re- 
agent that  has  any  action  on  it,  is  caustic 
fixed  alkali.  When  exposed  to  the  fire 
with  this,  and  the  mass  afterward  lixivia- 
ted, it  partly  dissolves  in  water,  and  may 
be  precipitated  by  means  of  an  acid  ;  but 
the  precipitate  is  not  in  the  least  attack- 
ed, whatever  the  quantity  of  acid  employ- 
ed. Separated  by  filtration,  and  dried,  it 
is  an  extremely  white  powder,  the  colour 
of  which  is  not  changed  by  a  red  heat. 
The  remainder  of  the  mass,  being  treated 
with  acids,  affords  the  same  powder.  Spe- 
cific gravity  after  ignition  6.5  It  is  fusi- 
ble with  the  blow-pipe  by  the  addition  of 
an  alkaline  phosphat  and  borat  of  soda, 
but  it  does  not  impart  any  colour  to  the 
flux. 

Exposed  to  a  strong  heat  in  a  crucible 


with  powdered  charcoal,  it  is  reduced  to 
a  moderately  hard  button,  having  a  me- 
tallic brilliancy  at  its  surface ;  but  its 
fracture  is  dull  and  blackish.  The  acids 
have  no  other  action  on  it,  than  convert- 
ing it  to  a  white  oxide. 

TAP  (JOCK.   See  Pneumatic  coc$. 

TAU.    See  Turpentine. 

TAU,  Mineral.    See  Bitumen. 

TAUUAS,  or  Terras,  a  volcanic  earth 
used  as  a  cement.  It  does  not  differ 
much  in  its  principles  from  puzzolana; 
but  it  is  much  more  compact,  hard,  po- 
rous, and  spongy.  It  is  generally  of  a 
whitish-yellow  colour,  and  contains  more 
heterogeneous  particles,  as  spar,  quartz, 
schoerl,  &c,  and  something  more  of  a 
calcareous  earth.  It  effervesces  with 
acids,  is  magnetic,  and  fusible  per  se. 
When  pulverized,  it  serves  as  a  cement, 
like  puzzolana.  It  is  found  in  Germ-any 
and  Sweden. 

When  reduced  to  powder,  and  mixed 
with  water,  Teras  forms  a  most  durable 
cement,  or  mortar,  which  is  advanta- 
geously employed  for  lining  basons,  cis- 
terns, 5cc. 

Mr  More  states,  that  red  earth  is  an  ex- 
cellent substitute  for  Tarras,  in  all  build- 
ings under  water.  Thus,  if  one  measure 
of  such  earth  be  mixed  with  an  equal  por- 
tion of  sand,  and  a  double  quantity  of 
well-slaked,  lime,  the  whole  will  form  a 
cement,  excellently  adapted  for  construc- 
ting dams,  bridges,  or  any  other  edifice  in 
water,  as  it  speedily  hardens,  and  acquires 
the  durability  of  stone. 

A  mixture  of  lime,  and  fine  gravel,  call- 
ed grout  by  the  masons,  is  also  useful  for 
the  same  purpose.    See  Cement. 

TAUT  AU.— Tartar  is  deposited  on  the 
sides  of  casks  during  the  fermentation  of 
wine :  it  forms  a  lining  more  or  less  thick, 
which  is  scraped  off.  This  is  called  crude 
tartar,  and  is  sold  in  Languedoc  from  10 
to  15  livres  the  quintal. 

All  wines  do  not  afford  the  same  quan- 
tity of  tartar.  Neumann  remarked,  that 
the  Hungarian  wines  left  only  a  thin  stra- 
tum ;  that  the  wines  of  France  afforded 
more ;  and  that  the  Uhenish  wines  afford- 
ed the  purest  and  the  greatest  quantity. 

Tartar  is  distinguished  from  its  colour 
into  red  and  white  ;  the  first  is  afforded 
by  red  wine. 

Tartar  is  purified  from  an  abundant  ex- 
tractive principle,  by  processes  which  are 
executed  at  Montpellier,  and  at  Venice. 

The  following  is  the  process  used  at 
Montpellier :  The  tartar  is  dissolved  in 
water,  and  suffered  to  crystallize  by  cool- 
ing.   The  crystals  are  then  boiled  in  ano 
ther  vessel,  with  the  addition  of  five  or 


TAR 


TEL 


six  pounds  of  the  white  argillaceous  earth 
of  Murviel  to  each  quintal  of  the  salt. 
After  this  boiling  with  the  earth,  a  very 
white  salt  is  obtained  by  evaporation, 
which  is  known  by  the  name  of  cream  of 
tartar,  or  the  acidulous  tartrite  of  potash. 

Mr.  Desmarets  has  informed  us,  that 
the  process  used  at  Venice  consists, 

1.  In  drying  the  tartar  in  iron  boilers. 

2.  Pounding  it,  and  dissolving  it  in  hot 
water,  which  by  cooling  afibrds  purer 
crystals. 

3.  Redissolving  these  crystals  in  water, 
and  clarifying  the  solution  by  whites  of 
eggs  and  ashes. 

The  process  of  Montpellier  is  prefera- 
ble to  that  of  Venice.  The  addition  of  the 
ashes  introduces  a  foreign  salt,  which  al- 
ters the  purity  of  the  product.    Sec  Au- 

GOL. 

Tartar  is  called  supertartrite  of  potash, 
purified  tartar,  crystals  of  tartar,  &;c.  It 
is  used  in  the  arts  and  in  medicine. 

TARTAR,  Salt  of    See  Potash. 

TART  A.  ROUS  ACID.— The  casks  in 
which  some  kinds  of  wine  are  kept  be- 
come incrusted  with  a  hard  substance, 
tinged  with  the  colouring  maUer  of  the 
wine,  and  otherwise  impure,  which  has 
long  been  known  by  the  name  of  argal,  or 
tartar,  and  distinguished  into  red,  and 
white,  according  to  its  colour.  This  be- 
ing purified  by  solution,  filtration,  crystal- 
lization, was  termed  cream,  or  crystals  of 
tartar.  It  was  afterward  discovered,  that 
it  consisted  of  a  peculiar  acid,  combined 
with  potash  :  and  the  supposition  that  it 
was  formed  during  the  fermentation  ol 
the  wine,  was  disproved  by  Roerhaave, 
Neumann  and  others,  who  showed  that  it 
existed  ready  formed  in  the  juice  of  the 
irrape.  It  has  likewise  been  found  in 
other  fruits,  particularly  before  they  are 
too  ripe;  and  in  the  tamarisk,  sumac, 
balm,  carduus  benedictus,  and  the  roots 
of  rest-harrow,  germander,  and  sage. 
The  separation  of  tartarous  acid  from  this 
acidulous  salt,  is  the  first  discovery  of 
Scheele  that  is  known.  He  saturated  the 
superfluous  acid  by  adding  chalk  to  a  so- 
lution of  the  supertartrite  in  boiling- water 
as  long  as  any  effervescence  ensued,  and 
expelled  the  acid  from  the  precipitated 
tartrite  of  lime  by  means  of  the  sulphuric, 
r'ourcroy  observes,  that  by  using  lime  in- 
stead of  its  carbonat,the  whole  or  the  tar- 
tarous acid  may  be  obtained ;  and  the  su- 
pernatant liquor  will  then  contain  pure 
potash,  instead  of  the  neutral  tan-trite  of 
potash,  which  it  holds  in  solution  when 
chalk  is  used.  Or  four  parts  of  tartar 
may  be  boiled  in  twenty  or  twenty-four 
of  water,  and  one  part  of  sulphuric  acid 


added  gradually.  By  continuing  the  boil- 
ing, the  sulphat  of  potash  will  fall  down. 
When  the  liquor  is  reduced  to  one  half, 
it  is  to  be  filtered,  and  if  any  more  sul- 
phat be  deposited  by  continuing  the  boil- 
ing, the  filtering  must  be  repeated.  AVhen 
no  more  is  thrown  down,  the  liquor  is  to 
be  evaporated  to  the  consistence  of  a  sy- 
rup, and  thus  crystals  of  tartarous  acid 
equal  to  half  the  weight  of  the  tartar  em- 
ployed, will  be  obtained. 

The  tartarous  acid  may  be  procured  irt 
needly  or  laminated  cnstals,  by  evapora- 
ting a  solution  of  it.  Its  taste  is  very  acid 
and  agreeable,  so  that  it  may  supply  the 
place  of  lemon  juice.  It  is  very  soluble 
in  water.  Burnt  m  an  open  fire  it  leaves 
a  coaly  residuum,  generally  containing  a 
little  lime  -.  in  close  vessels  it  gives  out 
carbonic  acid  and  hydrogen  gas,  so  that 
its  base  is  a  compound  of  hydrogen  and 
carbon.  By  distilling  nitric  acid  oft"  the 
crystals  they  may  be  converted  into  oxalic 
acid,  and  the  nitric  acid  passes  to  the  state 
of  nitrous. 

TELLURIUM. — Tellurium  is  a  new 
metal  discovered  by  Klaproth,  in  the  year 
1797.  It  is  found  in  three  different  ores  ; 
namely,  I.  In  the  white  gold  ore  of  Fatzc- 
bay,  formerly  named  aurum  paradoxum, 
found  in  the  mine  called  Maria-hilf,  in  the 
mountains  of  Fatzebay,  in  Transylvania. 
In  this  ore  tellurium  exists  alloyed  with 
gold  and  iron.  Its  colour  is  between  tin- 
white  and  lead-gray.  It  is  in  general 
found  massive.  The  texture  of  this  ore 
is  granular,  and  its  lustre  considerably 
metallic.  2.  In  the  graphic  gold  ore,  (uu- 
rum  graphicum)  of  Ofienbanya,  it  is  alloy- 
ed with  gold  and  silver.  This  ore  is  com- 
posed of  flat  prismatic  crystals,  the  ar- 
rangement of  which  has  some  resemblance 
to  Turkish  letters  ;  hence  the  name  of  the 
ore.  It  has  a  metallic  lustre,  and  a  tin- 
white  colour,  with  a  tinge  of  brass  yellow. 
3.  It  exists  also  in  the  ore  known  under 
the  name  of  the  yellow  foliated  gold  ore  of 
Aagzag,  alloyed  with  gold,  lead,  silver, 
copper,  and  sulphur. 

Tellurium  is  obtained,  according  to  Kla- 
proth, by  forming  oxyd  of  tellurium  into 
a  paste,  with  a  few  drops  of  linseed  oil, 
and  then  putting  it  into  a  small  glass  re- 
tort or  crucible.  As  the  oil  becomes  de- 
composed, brilliant  and  metallic  drops  are 
observed  on  the  upper  part  of  the  vessel, 
which  increase  in  number  until  the  oxyd 
is  revived. 

The  process  for  obtaining-  oxyd  of  tel- 
lurium may  be  seen  in  the  following  ana- 
Lysis. 

Let  the  white  gold  ore  be  gently  heat- 
ed with  six  parts  of  muriatic  acid  ;  three 


TER 


TES 


parts  of  the  nitric  being  then  added,  the 
mixture  is  boiled,  upon  which  there  arises 
a  considerable  effervescence,  and  a  com- 
plete solution  is  obtained.  The  littered 
solution  must  be  diluted  with  us  much 
water  as  it  can  bear  without  becoming- 
turbid,  which  is  a  very  small  quantity  ; 
and  a  solution  of  potash  is  then  to  be  add- 
ed to  the  liquor,  until  the  white  precipi- 
tate, which  is  at  first  formed  disappears, 
and  nothing  remains  but  a  brown  flaky 
sediment,  which  is  the  oxydof  gold  mix- 
ed with  the  oxyd  of  iron  contained  in  the 
ore.  This  may  be  dissolved  in  nitro-mu- 
riatic  acid,  and  the  gold  be  precipitated 
by  a  solution  of  nitrate  of  mercury,  and 
then  the  iron  by  potash.  Muriatic  acid  is 
then  added  to  the  before  obtained  alka- 
line solution,  in  sufficient  quantity  to  sa- 
turate the  potash,.  An  excess  of  the  acid 
must  be  avoided.  A  white  precipitate  is 
thus  produced  in  great  abundance.  This 
w  hen  washed,  is  the  oxyd  of  tellurium. 

TEMPERING  ■ — Cutting  instruments 
of  steel,  after  being  finished,  are  harden- 
ed by  heating  them  to  a  cherry  red,  and 
then  plunging  them  into  a  cold  liquid. 
After  this  hardening,  it  is  necessary  to 
soften  them  a  little,  or  to  temper  them  as 
it  is  called,  in  order  to  obtain  a  fine  and 
desirable  edge.  This  is  done  by  heating 
them  till  some  particular  colour  appears 
on  their  surface.  The  usual  way  is  to 
keep  them  in  oil,  heated  to  a  particular 
temperature,  till  the  requisite  colour  ap- 
pear. These  colours  follow  one  another 
in  regular  succession.  Between  430  de- 
grees and  150  degrees,  the  instrument 
appears  of  a  pale  yellow  tinge ;  at  460  de- 
grees the  colour  is  a  straw  yellow,  and 
the  instrument  has  the  usual  temper  of 
penknives,  razors,  and  ether  fine-edged 
tools.  At  500  degrees,  a  brownish  me- 
tallic yellow  is  given.  As  the  heat  in- 
creases, the  surface  is  successively  \  el- 
low,  brown  red,  and  purple,  to  580  de- 
grees, when  it  becomes  of  a  uniform  deep 
blue,  like  that  of  watch  springs.  The 
blue  gradually  weakens  to  a  water  colour, 
which  is  the  last  shade  distinguishable  be- 
fore the  instrument  becomes  red  hot. 

TENNANT'S  BLEACHING  POW- 
DER. See  Bleaching,  and  Appendix 
to  vol.  i. 

TERRA  LEMNTA.  A  red  bolar  earth. 
TERRA  MERITA.  See  Turmeric. 
TERRA  PON  DEROSA,  Barytes.  See 
Earths. 

TERRA  SIENNA. — A  brown  bole,  or 
ochre,  with  an  orange  cast,  brought  from 
Sienna  in  Italy,  and  used  in  painting,  both 
raw  and  burnt.  When  burnt  it  becomes 
of  a  darker  brown.  It  resists  the  fire  a 
long  time  without  fusing.   It  adheres  to 


the  tongue  very  forcibly.    See  Colour- 
making. 

TERRA  SIGILLATA.  When  the  boles 
were  much  more  esteemed  for  medical 
purposes  than  they  are  at  present,  and 
supposed  to  differ  considerably  in  their 
virtues,  some  of  them  were  impressed 
with  a  seal,  as  of  particular  excellence, 
and  hence  called  sealed  earths. 
TERRAS.  See  Tarras. 
TERRE  VERTE.—  This  is  used  as  a 
pigment,  and  contains  iron  in  some  un- 
known -state,  mixed  with  clay,  and  some- 
times with  chalk  and  pyrites ;  alum  and 
sulphat  of  lime  are  also  accidentally  found 
with  it.  It  is  difficultly  soluble  in  acids, 
is  not  magnetic  before  calcination,  and  be- 
comes of  a  coffee-colour  when  heated.  It 
is  said  to  afford  about  40  per  cent,  of  iron. 

TESTS,  Reagents. — The  number  of  ar- 
ticles which  are  used  for  experiments, 
analyses,  &c.  by  chemists,  in  order  to  ef- 
fect decompositions,  and  compositions, 
and  to  determine  the  presence  or  absence 
of  certain  bodies,  are  called  tests,  or  re- 
agents. They  are  "  the  compass  by  which 
the  chemist  steers."  It  is  obvious,  that 
as  reagents  effect  new  changes,  and  as 
these  changes  are  determined  by  the  laws 
of  affinity,  {heir  number  must  be  great, 
as  well  as  their  effects  various.  It  is  by  a 
knowledge  of  these  facts,  that  the  accu- 
racy of  an  analysis,  or  examination,  is  de- 
termined. 

The  following  remarks,  accompanying 
a  catalogue  of  the  most  necessary  tests, 
for  the  examination  of  mineral  waters  in 
particular,  we  extract  from  Henry's  Che- 
mistry, 8vo.  page  309. 

"  The  use  of  tests,  or  re-agents,  has 
been  employed  by  Mr.  Kirwan,  to  ascer- 
tain, by  a  careful  examination  of  the  pre- 
cipitate, not  only  the  kind,  but  the  quanti- 
ty, of  the  ingredients  of  mineral  waters. 
This  will  be  best  understood  from  an  ex- 
ample. It  is  an  established  fact,  that  100 
parts  of  crystallized  muriate  of  soda,  when 
completely  decomposed  by  nitrate  of  sil- 
ver, yield,  as  nearly  as  possible,  235  of 
precipitate.  From  the  weight  of  the  pre- 
cipitate, separated  by  nitrat  of  silver 
from  a  given  quantity  of  any  w^ater,  it  is 
therefore  easy,  when  no  other  muriatic 
salt  is  present,  to  infer,  what  quantity  of 
muriate  of  soda  was  contained  in  the  wa« 
ter ;  sir.ee  every  hundred  grains  of  mu- 
riated  silver  indicate,  pretty  accurately, 
42^  of  crystallized  common  salt.  The 
same  mode  of  estimation  may  be  applied 
in  various  other  instances  ;  and  the  rule 
for  each  individual  case,  is  given  by  Mr. 
Kirwan,  in  part  ii,  chap,  ii,  of  his  Essay  on 
the  Analysis  of  Mineral  Waters.  Inmost 
instances,  also,  it  will  be  found  stated  in 


TES 


TES 


the  following- description  of  the  use  of  the 
various  re-agents. 

I.  Lifusion  of' Litmus,  Syrup  of  Violets,  Lfc. 

The  infusion  of  litmus  is  prepared  by 
steeping  this  substance,  first  bruised  in  a 
mortar,  and  tied  up  in  a  thin  rag,  in  dis- 
tilled water,  which  extracts  its  blue  co- 
lour. 

If  the  colour  of  the  infusion  tends  too 
much  to  purple,  it  may  be  amended  by  a 
drop  or  two  of  solution  of  pure  ammonia  ; 
but  of  this  no  more  must  be  added  than 
is  barely  sufficient,  lest  the  delicacy  of 
the  test  should  be  impaired. 

The  syrup  of  violets  is  not  easily  ob- 
tained pure.  The  genuine  syrup  may  be 
distinguished  from  the  spurious  by  a  so- 
lution of  corrosive  sublimate,  which 
changes  the  former  to  green,  while  it  red- 
dens the  latter.  When  it  can  be  procured 
genuine,  it  is  an  excellent  test  of  acids, 
and  may  be  employed  in  the  same  man- 
ner as  the  infusion  of  litmus. 

Paper  stained  with  the  juice  of  the 
March  violet,  or  with  that  of  the  scrapings 
of  radishes,  answers  a  similar  purpose. 
In  staining  poper  for  the  purposes  of  a 
test,  it  must  be  used  unsized  ;  or,  if  sized, 
it  must  previously  be  well  washed  with 
warm  water ;  because  the  alum,  which 
enters  into  the  composition  of  the  size, 
will  otherwise  change  the  vegetable  co- 
lour to  red. 

In  the  Philosophical  Magazine,  vol.  1, 
p.  180,  may  be  found  some  recipes  for 
test  liquors,  invented  by  Mr.  Watt. 

Infusion  of  litmus  is  a  test  of  most  un- 
combined  acids. 

1.  If  the  infusion  redden  the  unboiled, 
but  not  the  boiled  water,  under  examina- 
tion o  r  if  the  red  colour,  occasioned  by 
adding  the  infusion  to  a  recent  water,  re- 
turn to  blue,  on  boiling;  we  may  infer, 
that  the  acid  is  a  volatile  one,  and  most 
probably  the  carbonic  acid.  Sulphuret- 
ted hydrogen  gas,  dissolved  in  water,  also 
reddens  litmus,  but  not  after  boiling. 

2.  To  ascertain  whether  the  change  be 
p'-oduced  by  carbonic  acid,  or  by  sulphu- 
retted hydrogen,  when  experiment  shows 
that  the  reddening  cause  is  volatile,  add 
a  little  lime  water,  or  in  preference,  bary- 
tic  water.  This,  if  carbonic  acid  be  pre- 
sent, will  occasion  a  precipitate,  which 
will  dissolve,  with  effervescence,  on  add- 
ing a  little  muriatic  acid.  Sulphuretted 
h)drogen  may  also  be  contained,  along 
with  carbonic  acid,  in  the  same  water ; 
which  will  be  determined  by  the  tests 
hereafter  to  be  described. 

3.  Paper  tinged  with  litmus  is  also  red- 
dened by  the  presence  of  carbonic  acid, 


but  regains  its  blue  colour  on  drying. 
The  mineral  and  fixed  acids  redden  it 
permanently.  That  these  acids,  however, 
may  produce  their  effect,  it  is  necessary 
that  they  should  be  present  in  a  sufficient 
proportion.  (See  Kiwan  on  Mineral  Wa- 
ters, p.  40)  The  dark -blue  paper,  which 
is  generally  wrapped  round  loaves  of  re- 
fined sugar,  is  not  discoloured  by  carbo* 
nic  acid  or  sulphuretted  h)drogen,  but 
only  by  the  stronger  acids. 

II.  Infusion  of  Litmus  reddened  by  Vinegar, 
— Tincture  of  Brasil-izood, — Tincture  of 
Turmeric,  and  Paper  stained  with  each 
of  these  three  Substances, — Syrup  of  Vio- 
lets. 

All  these  different  tests  have  one  and 
the  same  object. 

1.  Infusion  of  litmus  reddened  by  vine- 
gar, or  litmus  paper  reddened  by  vinegar, 
has  its  blue  colour  restored  by  pure  alka- 
lies and  pure  earths,  and  by  carbonated 
alkalies  and  earths. 

2.  Turmeric  paper  and  tincture  are 
changed  to  a  reddish-brown  by  alkalies, 
whether  pure  or  carbonated,  and  by  pure 
earths,  but  not  by  carbonated  earths. 

3.  The  red  infusion  of  brazil-wood,  and 
paper  stained  with  it,  become  blue  by  al- 
kalies and  earths,  and  even  by  the  latter, 
when  dissolved  by  an  excess  of  carbonic 
acid.  In  the  last-mentioned  case,  how- 
ever, the  change  will  either  cease  to  ap- 
pear, or  will  be  much  less  remarkable, 
when  the  water  has  been  boiled. 

4.  Syrup  of  violets,  when  pure,  is,  by 
the  same  causes,  turned  green ;  as  is  also 
paper  stained  with  the  juice  of  the  violet, 
or  with  the  scrapings  of  radishes. 

According  to  Mr.  Accum,  syrup  of 
violets,  which  has  lost  its  colour  by  keep- 
ing, may  be  restored  by  agitation,  during 
a  few  minutes,  in  contact  with  oxygen 
gas. 

III.  Tincture  of  Galls. 
Tincture  of  galls  is  the  test  generally 
employed  for  discovering  iron  ;  with  all 
combinations  of  which  it  produces  a  black 
tinge,  more  or  less  intense  according  to 
the  quantity  of  iron.  The  iron,  however, 
in  order  to  be  detected  by  this  test,  must 
be  in  the  state  of  red  oxyde,  or,  if  oxy- 
dized  in  a  less  degree,  its  effect  will  not. 
be  apparent,  unless  after  standing  some, 
time  in  contact  with  the  air.  By  applying 
this  test  before  and  after  evaporation,  or 
boiling,  we  may  know  whether  the  iron 
be  held  in  solution  by  carbonic  acid,  or  by 
a  fixed  acid.  For, 

1.  If  it  produce  its  effect  before  the  ap- 
plication of  heat,  and  not  afterward,  car- 
bonic acid  is  the  solvent- 


TES 


TES 


2.  If  after,  as  well  as  before,  a  mineral 
acid  is  the  solvent. 

3.  If,  by  the  boiling,  a  yellowish  pow- 
der be  precipitated,  and  yet  galls  conti- 
nue to  strike  the  water  black,  the  iron,  as 
often  happens,  is  dissolved  both  by  car- 
bonic acid  and  by  a  fixed  acid.  A  neat 
mode  of  applying-  the  gall  test  was  used 
by  M.  Klaprotb,  in  his  analysis  of  the 
Carlsbad  water;  a  slice  of  the  gall-nut 
was  suspended  by  a  silken  thread  in  a 
large  bottle  of  the  recent  water,  and  so 
small  was  the  quantity  of  iron,  that  it 
could  only  be  discovered  in  water  fresh 
from  the  spring,  by  a  slowly  -formed  and 
dark  cloud,  surrounding  {lie  re-agent. 
(Klaproth,  vol.  i,  p.  279.) 

IV.  Sulphuric  Acid. 

1.  Sulphuric  acid  discovers,  by  a  slight 
effervescence,  the  presence  of  carbonic 
acid,  whether  uncombined  or  united  with 
alkalies  or  earths. 

2.  If  lime  be  present,  whether  pure  or 
uncombined,  the  addition  of  sulphuric 
acid  occasions,  after  a  few  days,  a  white 
precipitate. 

3.  Barytes  is  precipitated  instantly,  in 
the  form  of  a  white  powder. 

4-  Nitric  and  muriatic  salts,  ia  a  dry 
state,  or  dissoh  ed  in  very  little  water,  on 
adding  sulphuric  acid,  and  applying  heat, 
are  decomposed;  and  if  a  stopper,  mois- 
tened with  solution  of  pure  ammonia,  be 
held  over  the  vessel,  white  clouds  will 
appear.  For  distinguishing  whether  ni- 
tric or  muriatic  acid  be  the  cause  of  this 
appearance,  rules  will  be  given  hereafter. 

V.  JS'itric  and  Nitrous  Jlcids. 
These  acids,  if  they  occasion  efferves- 
cence, give  the  same  indications  as  the 
sulphuric.  The  nitrous  acid  has  been  re- 
commended as  a  test  distinguishing  be- 
tween hepatic  waters  that  contain  hydro- 
sulphuret  of  potash,  and  those  that  con- 
tain only  sulphuretted  hydrogen  gas.  In 
the  former  case,  a  precipitate  ensues  on 
adding  nitrous  acid,  and  a  very  fetid  smell 
arises;  in  the  latter,  a  slight  cloudiness 
only  appears,  and  the  smell  of  the  water 
becomes  less  disagreeable. 

VI.  Oxalic  Acid  and  Oxalates. 
This  acid  is  a  most  delicate  test  of 
lime,  which  it  separates  from  all  its  com- 
binations. 

1.  If  a  water,  which  is  precipitated  by 
oxalic  acid,  become  milky  on  adding  a 
watery  solution  of  carbonic  acid,  or  by 
blowing  air  through  it  from  the  lungs,  by 
means  of  a  quill  or  glass  tube,  we  may 
infer,  that  pure  lime  (or  barvtes,  which 
VOL.  IT. 


has  never  yet  been  found  pure  in  waters) 
is  present. 

2.  If  the  oxalic  acid  occasion  a  preci- 
pitate before,  but  not  after  boiling,  the 
lime  is  dissolved  by  an  excess  of  carbonic 
acid ; 

3  If  after  boiling,  by  a  fixed  acid.  A 
considerable  excess  of  any  of  the  mineral 
acids,  however,  prevents  the  oxalic  acid 
from  occasioning  a  precipitate,  even 
though  lime  be  present;  because  some 
acids  decompose  the  oxalic,  and  others, 
dissolving  the  oxalate  lime,  prevent  it 
from  appearing.  (A  id.  Kirwan  on  Wa- 
ters, p.  88.) 

The  oxalate  of  ammonia,  or  of  potash 
(which  may  easily  be  formed  by  saturat- 
ing the  respective  carbonates  (if  these  al- 
kalies with  a  solution  of  oxalic  acid),  are 
not  liable  to  the  above  objection,  and  are 
preferable,  as  re-agents,  to  the  uncombin- 
ed acid  Yet  even  these  oxalates  fail  to 
detect  lime  when  supersaturated  with 
muriatic  or  nitric  acids  ;  and,  if  such  an 
excess  be  present,  it  must  be  saturated, 
before  adding  the  test,  with  pure  ammo- 
nia. A  precipitation  will  then  be  produced. 

The  quantity  of  lime,  contained  in  the 
precipitate,  may  be  known,  by  first  cal- 
cining it  with  access  of  air,  which  con- 
verts the  oxalate  into  a  carbonate ;  and 
by  expelling,  from  this  last,  its  carbonic 
acid,  by  calcination,  with  a  strong  heat, 
in  a  covered  crucible.  According  to  Dr. 
Marcet,  117  grains  of  sulphate  of  lime 
give  100  of  oxalate  of  lime,  dried  at  160^ 
Fahrenheit. 

The  fluatc  of  ammonia,  recommended 
by  Scheele,  1  find  to  be  a  most  delicate 
test  of  lime.  It  may  be  prepared  by  add- 
ing carbonate  of  ammonia  to  diluted  flu. 
oric  acid,  in  a  leaden  vessel,  observing 
that  there  be  a  small  excess  of  acid. 

VH.  Pure  Alkalies  and  carbonated  Alkalies. 

1.  The  pure  fixed  alkalies  precipitate 
all  earths  and  metals,  whether  dissolved, 
by  volatile  or  fixed  menstrua,  but  only  in 
certain  states  of  dilution  ;  for  example, 
sulphate  of  alumine  may  be  present  in 
water,  in  the  proportion  of  4  grains  to 
500,  without  being  discovered  by  pure 
fixed  alkalies.  As  the  alkalies  precipi- 
tate so  many  substances,  it  is  evident  that, 
they  cannot  afford  any  very  precise  infor- 
mation, when  employed  as  re-agents. 
Fi'om  the  colour  of  the  precipitate,  as  it 
approaches  to  a  pure  white,  or  recedes 
from  it,  an  experienced  eye  will  judge, 
that  the  precipitated  earth  contains  less  or 
more  of  metallic  admixture;  and  its  pre- 
cise composition  must  be  ascertained  by 
rules  which  will  presently  be  given.  ■ 


TES 


TES 


Z.  Ture  fixed  alkalies  also  decompose 
all  salts  with  basis  of  ammonia,  which 
becomes  evident  by  its  smell  (except  the 
salts  are  dissolved  in  much  water),  and 
also  by  the  white  fumes  it  exhibits  when 
a  stopper,  moistened  with  muriatic  acid, 
is  brought  near. 

3.  Carbonates  of  potash  and  of  soda 
have  similar  effects. 

4.  Pure  ammonia  precipitates  all  earthy 
and  metallic  salts.  Besides  this  property, 
it  also  imparts  a  deep  blue  colour  to  any 
liquid  that  contains  copper  or  nickel  in  a 
state  of  solution. 

5.  Carbonate  of  ammonia  has  the  same 
properties,  except  that  it  does  not  preci- 
pitate magnesia  from  its  combinations 
Hence,  to  ascertain  whether  this  earth  be 
present  in  any  solution,  add  the  carbonate 
of  ammonia  till  no  farther  precipitation  en- 
sues ;  filter  the  liquor ;  raise  it  nearly  to 
212°  Fahrenheit ;  and  then  add  pure  am- 
monia. If  any  precipitation  now  occurs, 
we  may  infer  the  presence  of  magnesia. 
It  must  be  acknowledged,  that  zircon,  yt- 
tria,  and  glucine,  would  escape  discovery 
by  this  process ;  but  they  have  never  yet 
been  found  in  mineral  waters ;  and  their 
presence  can  scarcely  be  expected. 

yill.  Lime-Water. 

1.  Lime-water  is  applied  to  the  pur- 
poses of  a  test,  chiefly  for  detecting  car- 
bonic acid.  Let  any  liquor  supposed  to 
contain  this  acid  be  mixed  with  an  equal 
bulk  of  lime-water.  If  carbonic  acid  be 
present,  either  free  or  combined,  a  pi*eci- 
pitate  will  immediately  appear,  which,  on 
adding  a  few  drops  of  muriatic  acid,  will 
again  be  dissolved  with  effervescence. 

2.  Lime-water  will  also  show  the  pre- 
sence of  corrosive  sublimate  by  a  brick- 
dust-coloured  sediment.  If  arsenous  acid 
(common  arsenic)  be  contained  in  a  li- 
quid, lime-water,  when  added,  will  occa- 
sion a  precipitate,  consisting  of  lime  and 
arsenous  acid,  which  is  very  difficultly 
soluble  in  water.  This  precipitate,  when 
mixed  up  with  oil,  and  laid  on  hot  coals, 
yields  the  well  known  garlic  smell  of 
arsenic. 

IX.  Pure  Bc.rytes,  and  its  Solution  in  Wa- 
ter. 

1.  A  solution  of  pure  barytes  is  even 
more  effectual  than  lime-water  in  detect- 
ing the  presence  of  carbonic  acid,  and  is 
much  more  portable  and  convenient  ; 
since,  from  the  crystals  of  this  earth,  the 
barytic  solution  may  at  any  time  be  im- 
mediately prepared.  In  discovering  car- 
bonic acid,  the  solution  of  barytes  is  used 
similarly  to  lime-water,  and,  if  this  acid 
be  present,  gives,  hi  like  maimer,  a  preci- 


pitate soluble  with  effervescence  in  dilute 
muriatic  acid. 

2  The  barytic  solution  is  also  a  most 
sensible  test  of  sulphuric  acid  and  its 
combinations,  which  it  indicates  by  a  pre- 
cipitate not  soluble  in  muriatic  acid. — 
Pure  strontites  has  similar  virtues  as  a 
test.  The  quantity  of  the  precipitated 
substance,  indicated  by  the  weight  of  the 
precipitate,  will  be  stated  in  No.  XV. 

X.  Metals. 

1.  Of  the  metals,  silver  and  mercury 
are  tests  of  the  presence  of  hydro-sul- 
phurets,  and  of  sulphuretted  hydrogen 
gas.  If  a  little  quick-silver  be  put  into  a 
bottle  containing  water  impregnated  with 
either  of  these  substances,  its  surface  soon 
acquires  a  black  film,  and,  on  shaking  the 
bottle,  a  blackish  powder  separates  from 
it.  Silver  is  speedily  tarnished  by  the 
same  cause. 

2.  Metals  may  be  used  also  as  tests  of 
each  other,  on  the  principle  of  elective  af- 
finity. Thus,  for  example,  a  polished  iron 
plate,  immersed  in  a  solution  of  sulphate 
of  copper,  soon  acquires  a  coat  of  this 
metal ;  and  the  same  in  other  similar  ex- 
amples. 

XI.  Sulphate  of  Iron. 
This  is  the  only  one  of  the  sulphates, 
except  that  of  silver,  applicable  to  the 
purposes  of  a  test  When  used  with  this 
view,  it  is  generally  employed  for  ascer- 
taining the  presence  of  oxygen  gas,  of 
which  a  natural  water  may  contain  a  small 
quantity. 

A  water,  suspected  to  contain  this  gas, 
may  be  mixed  with  a  little  recently-dis- 
solved sulphute  of  iron,  and  kept  corked 
up,  in  a  vial  completely  filled  by  the  mix- 
ture- If  an  oxide  of  iron  be  precipitated 
in  the  course  of  a  few  days,  the  water 
may  be  inferred  to  contain  oxygen  gas. 

XII.   Sulphate,  Nitrate,  and  Acetate  oj 
Silver. 

These  solutions  are  all,  in  some  mea- 
sure, applicable  to  the  same  purpose. 

1.  They  are  peculiarly  adapted  to  the 
discovery  of  muriatic  acid  and  of  mu- 
riates. For  the  silver,  quitting  its  solvent, 
combines  with  the  muriatic  acid,  and 
forms  a  flaky  precipitate,  which,  at  first, 
is  white,  but,  on  exposure  to  the  sun's 
light,  acquires  a  bhieish,  and  finally  a 
black  colour.  This  precipitate  Dr.  Black 
states  to  contain,  in  1000  parts,  as  much 
muriatic  acid  as  would  form  425^  of  crys- 
tallized muriate  of  soda,  which  estimate 
scarcely  differs  at  all  from  that  of  Klap- 
roth.  The  same  quantity  of  muriate  of 
silver  (1000  parts)  indicates,  according  tc 


TES 


TES 


Kirvvan,  454$  of  muriate  of  potash.  A 
prestation,  however,  may  arise  from 
other  causes,  which  it  may  be  proper  to 
state. 

2.  The  solutions  of  silver  in  acids  are 
precipitated  by  carbonated  alkalies  and 
earths.  The  agency  of  the  alkalies  and 
earths  may  be  prevented,  by  previously 
saturating1  them  with  a  few  drops  of  the 
same  acid  in  which  the  silver  is  dissolved. 

3.  The  nitrate  and  acetate  of  silver  are 
decomposed  by  the  sulphuric  and  sulphu- 
rous acids  ;  but  this  may  be  prevented  by 
adding1,  previously,  a  lew  drops  of  nitrate 
or  acetite  of  barytes,  and,  after  allowing- 
the  precipitate  to  subside,  the  clear  liquor 
may  be  decanted,  and  the  solution  of  sil- 
ver added.  Should  a  precipitation  now 
take  place,  the  presence  of  muriatic  acid, 
or  some  one  of  its  combinations,  may  be 
suspected.  To  remove  uncertainty,  whe- 
ther a  precipitation  be  owing  to  sulphuric 
or  muriatic  acid,  a  solution  of  sulphate  of 
silver  may  be  employed,  which,  when  no 
uncombined  alkali  or  earth  is  present,  is 
affected  only  by  the  latter  acid.  Accord- 
ing to  professor  Pfaff,  one  part  of  mu- 
riatic acid  of  the  specific  gravity,  1.15, 
diluted  with  70,000  parts  of  water,  bare- 
ly exhibits  a  slight  opaline  tinge,  when 
tested  with  nitrate  of  silver ;  and,  when 
diluted  with  80,000  parts  of  water,  it  is 
not  affected  at  all. 

4.  The  solutions  of  silver  are  also  pre- 
cipitated by  sulphuretted  hydrogen,  and 
by  hydro-sulphurets';  but  the  precipitate 
is  then  reddish,  or  brown,  or  black  ;  or  it 
may  be,  at  first,  white,  and  afterwards  be- 
come speedily  brown  or  black.  It  is  solu- 
ble, in  great  part,  in  dilute  nitrous  acid, 
which  is  not  the  case  if  occasioned  by 
muriatic  or  sulphuric  acid. 

5.  The  solutions  of  silver  are  precipi- 
tated by  extractive  matter ;  but,  in  this 
case,  also,  the  precipitate  has  a  dark  co- 
lour, and  is  soluble  in  nitrous  acid. 

XIII.  Nitrate  and  Acetate  of  J^ead. 

1.  Acetate  of  lead,  the  most  eligible  of 
these  two  tests,  is  precipitated  by  sulphu- 
ric and  muriatic  acids ;  but,  as  of  both 
these  we  have  much  better  indicators,  I 
do  not  enlarge  on  its  application  to  this 
purpose. 

2.  The  acetate  is  also  a  test  of  sulphu- 
retted hydrogen  and  of  hydro-sulphurets 
of  alkalies,  which  occasion  a  black  preci- 
pitate ;  and,  if  a  paper,  on  which  charac- 
ters are  traced  with  a  solution  of  acetate 
of  lead,  be  held  over  a  portion  of  water 
containing"  sulphuretted  hydrogen  gas, 
they  are  soon  rendered  visible  j  especially 
when  the  water  is  a  little  warmed. 

3.  The  acetate  of  lead  is  employed  in 


the  discovery  of  uncombined  boracic  acid, 
a  very  rare  ingredient  of  waters.  To 
ascertain  whether  this  be  present,  some 
cautions  are  necessary.  [aS  The  uncom- 
bined alkalies  and  earths  (if  any  be  sus- 
pected) must  be  saturated  with  acetic  or 
acetous  acid,  (Z\)  The  sulphates  must 
be  decomposed  by  acetate  or  nitrate  of 
barytes,  and  the  muriates  by  acetate  or  ni- 
trate of  silver.  The  filtered  liquor,  if  bo- 
racic acid  be  contained  in  it,  will  continue 
to  give  a  precipitate,  which  is  soluble  in 
nitric  acid  of  the  specific  gravity  1.3. 

4.  Acetate  of  lead  is  said,  also,  by 
Pfaff,  to  be  a  very  delicate  test  of  carbo- 
nic acid  ;  and  that  it  renders  milky,  water 
which  contains  the  smallest  quantity  of 
this  acid. 

XIV.  Nitrate  of  Mercury,  prepared  faith 

and  without  Jleat. 
This  solution,  differently  prepared,  is 
sometimes  employed  as  a  test. 

1.  The  solution  of  nitrate  of  mercury, 
prepared  without  heat,  has  been  found  by 
Pfaff  to  be  a  much  more  sensible  test  of 
muriatic  acid,  than  nitrate  of  silver.  Its 
sensibility,  indeed,  is  so  great,  that  one 
part  of  muriatic  acid,  of  the  specific  gra- 
vity 1.50  diluted  with  300,000  parts  of 
water,  is  indicated  by  a  slightly  dull  tint 
ensuing  on  the  addition  of  the  test. 

2.  It  is,  at  the  same  time,  the  most 
sensible  test  of  ammonia,  one  part  of 
which,  with  30,000  parts  of  water,  is  in- 
dicated by  a  slight  blackish  yellow  tint, 
on  adding  the  nitrate  of  mercury. 

3.  The  nitrate  of  mercury  is  also  pre- 
cipitated by  highly  diluted  phosphoric 
acid  ;  but  the  precipitate  is  soluble  in  an 
excess  of  phosphoric  or  nitric  acid,  which 
is  not  the  case  if  it  has  been  occasioned 
by  muriatic  acid. 

XV.  Muriatei  Nitrate;  and  Acetate  of  Ba- 

rytes. 

1.  These  solutions  are  all,  most  delicate 
tests  of  sulphuric  acid  and  of  its  combi- 
nations, with  which  they  give  a  white  pre- 
cipitate, insoluble  in  dilute  muriatic  acid. 
They  are  decomposed,  however,  by  car- 
bonates of  alkali ;  but  the  precipitate  oc- 
casioned by  carbonates  is  soluble  in  di- 
lute muriatic,  or  nitric  acid,  with  efferves- 
cence, and  may  even  be  prevented  by 
adding,  previously,  a  few  drops  of  the 
same  acid  as  that  contained  in  the  barytic 
salt,  which  is  employed. 

One  hundred  grains  of  dry  sulphate  of 
barytes  contain  (according  to  Klaproth, 
vol.  i.  p.  168.)  about  45A  of  sulphuric  acid 
of  the  specific  gravity  1850 ;  according  to 
Clayfield  (Nicholson's  Journal,  4to.  in. 
38.)  33  of  acid,  of  specific  gravity  ??40  ; 


TEb 


1ES 


according  to  Thcnard,  after  calcination, 
about  25;  and,  according  to  Mr.  Kirvvan, 
after  ignition,  23  . 5  of  real  acid.  The  same 
chemist  states,  that  170  grains  of  ignited 
sulphate  of  barytes  denote  100  of  dried 
sulphate  of  soda;  while  136  36  of  the 
same  substance  indicate  100  of  dry  sul- 
phate of  potash ;  and  100  parts  result 
from  the  precipitation  of  52.11  of  sulphate 
of  magnesia. 

From  Klaproth's  experiments,  it  ap- 
pears, that  1000  grains  of  sulphate  of  ba- 
rytes indicate  595  of  desiccated  sulphate 
of  soda,  or  141(3  of  the  crystallized  salt 
The  same  chemist  has  shown,  that  100 
grains  of  sulphate  of  barytes  are  produc 
ed  by  the  precipitation  of  71  grains  of  sul- 
phate of  lime. 

2-  Phosphoric  salts  occasion  a  precipi- 
tate also,  which  is  soluble  in  muriatic  acid 
without  effervescence. 

XVI.  Prussiates  of  Potash  and  of  Lime. 

Of  these  two,  the  prussiate  of  potash 
is  the  most  eligible.  When  pure,  it  does 
not  speedily  resume  a  blue  colour  on  the 
addition  of  an  acid,  nor  does  it  immediate- 
ly precipitate  muriate  of  barytes. 

Prussiate  of  potash  is  a  very  sensible 
test  of  iron,  with  the  solutions  of  which 
in  acids  it  produces  a  Prussian  blue  pre- 
cipitate, in  consequence  of  a  double  elec- 
tive affinity.  To  render  its  effect  more 
certain,  however,  it  may  he  proper  to  add, 
previously,  to  any  water  suspected  to  con- 
tain iron,  a  little  muriatic  acid,  with  a 
view  to  the  saturation  of  uncombined 
alkaiies  or  earths,  which,  if  present,  pre- 
vent the  detection  of  very  minute  quanti- 
ties of  iron. 

1.  If  a  water,  after  boiling  and  filtra- 
tion, does  not  afford  a  blue  precipitate,  on 
the  addition  of  prussiate  of  potash,  the 
solvent  of  the  iron  may  be  inferred  to  be 
a  volatile  one,  and  probably  the  carbonic 
acid. 

2.  Should  the  precipitation  ensue  in  the 
boiled  water,  the  solvent  is  a  fixed  acid, 
the  nature  of  which  must  be  ascertained 
by  other  tests. 

In  using  the  prussian  test  for  the  disco- 
very of  iron,  considerable  caution  is  ne- 
ces  ary,  in  order  to  attain  accurate  re- 
sults. The  prussiate  should,  on  all  occa- 
sions, be  previously  crystallized;  and  the 
quantity  of  oxide  of  iron,  essential  to  its 
constitution,  or  at  least  an  invariable  ac- 
companiment, should  be  previously  ascer- 
tained in  the  following  manner.  Expose 
a  known  weight  of  the  crystallized  salt 
to  a  low  red-heat  in  a  silver  crucible.  Af- 
fusing  and  boiling  up,  it  will  become  dry, 
and  will  then  blacken.  Let  it  cool ;  wash 
off  the  soluble  part  j  collect  the  rest  on  a 


iilter ;  dry  it,  and  again  calcine  it  with  a 
little  wax.  Let  it  be  again  weighed?  and 
the  result  will  show  the  proportion  of  ox- 
ide of  iron  present  in  the  salt  which  has 
been  examined.  This  varies  from  22  to 
30  and  upwards  per  cent-  When  the  test 
is  employed  for  discovering  iron,  let  a 
known  weight  of  the  salt  be  dissolved  in 
a  given  quantity  of  water  ;  add  the  solu- 
tion gradually  ;  and  observe  how  much  is 
expended  in  effecting  the  precipitation 
Before  collecting  the  precipitate,  warm 
the  liquid,  which  generally  throws  down 
a  further  portion  of  prussian  blue.  Let 
the  whole  be  washed  and  dried,  and  then 
calcined  with  wax.  From  the  weight  of 
the  oxide  obtained,  deduct  that  quantity 
which,  by  the  former  experiment,  is 
known  to  be  present  in  the  prussiate  that 
has  been  added ;  and  the  remainder  will 
denote  the  quantity  of  oxide  of  iron,  pre- 
sent in  the  liquid  which  is  under  exami 
nation. 

3.  Besides  iron,  the  prussiated  alkalies 
also  precipitate  muriate  of  alumine.  No 
conclusion,  therefore,  can  be  deduced,  re- 
specting the  non-existence  of  muriate  of 
alumine  from  any  process,  in  which  the 
prussic  test  has  previously  been  used.  It 
will,  therefore,  be  proper,  if  a  salt  of  alu- 
mine be  indicated  by  other  tests,  to  exa- 
mine the  precipitate  effected  by  prussiate 
of  potash.  This  may  be  done  by  repeat 
ediy  boiling  it  to  dryness  with  muriatic 
acid,  which  takes  up  the  alumine,  and 
leaves  the  prussiate  of  iron.  From  the 
muriatic  solution,  the  alumine  may  be  pre- 
cipitated by  a  solution  of  carbonate  ot 
potash. 

4.  According  to  Klaproth  (ii.  55.)  solu- 
tions of  yttria,  (which  earth,  however,  is 
not  likely  to  be  present  in  any  mineral 

.  water)  afford  with  the  prussian  test,  a 
j  white  precipitate,  passing  to  pearl-gray, 
|  which  .consists  of  prussiate  of  yttria. 
'  This  precipitate  disappears  on  adding  an 
'  acid,  and  hence  may  be  separated  from 
prussiated  iron.  The  same  accurate  che- 
mist states,  that  the  prussian  test  lias  no 
i  action  on  salts  with  base  of  glucine  (ib.)  ; 
j  but  that  it  precipitates  zircon  from  its  so- 
'  lutions.  (ii.  214.) 

The  prussiated  alkalies  decompose,  al- 
so, all  metallic  solutions,  excepting  those 
of  gold,  platina,  iridium,  rhodium,  osmi- 
um, and  antimony. 

XVII.  Succinate  of  Soda  and  Ammonia. 
L  The  succinate  of  soda  was  first  re- 
commended by  Gehlen,  and  afterwards 
employed  by  Klaproth  (Contributions,  II, 
48.)  for  the  discovery  and  separation  of 
iron.  The  salt  with  base  of  ammonia  has 
also  been  used  for  a  similar  purpose  by 


rFES 


TES 


Dp.  Marcet,  physician  to  Guy's  Hospital, 
in  a  skilful  analysis  of  the  Brighton  cha- 
lybeate, which  is  published  in  the  new 
edition  of  Dr.  Saunders's  Treatise  on  Mi- 
neral Waters. 

The  succinic  test  is  prepared  by  satu- 
rating- carbonate  of  soda  or  ammonia  with 
this  acid.  In  applying-  the  test,  it  is  ne- 
cessary not  to  use  more  than  is  sufficient 
for  the  purpose ;  because  an  excess  of  it 
re-dissolves  the  precipitate.  The  best 
mode  of  proceeding,  is  to  heat  the  solu- 
tion containing  iron,  and  to  add  gradually 
the  solution  of  succinate,  until  it  ceases 
to  produce  any  effect.  A  brownish  pre- 
cipitate is  obtained,  consisting  of  succi- 
nate of  iron  This,  when  calcined  with  a 
little  wax,  in  a  low  red  heat,  gives  an  ox- 
ide of  iron,  containing  about  70  per  cent 
of  the  metal.  From  Dr.  Marcet's  experi- 
ments, it  appears,  that  100  grains  of  iron, 
dissolved  in  sulphuric  acid,  then  precipi- 
tated by  the  succinate  test,  and  after- 
wards burned  with  wax,  gave  148  of  ox- 
ide of  iron  ;  that  is,  100  grains  of  the  oxide 
indicate  about  67^  of  metallic  iron. 

2.  The  succinates,  however,  it  is  stated 
by  Dr.  Marcet  and  Mr.  Ekeberg,  precipi- 
tate alumine,  provided  there  be  no  consi- 
derable excess  of  acid  in  the  aluminous 
salt.  On  magnesia  it  has  no  action,  and 
hence  may  be  successfully  employed  in 
the  separation  of  these  two  earths.  If  100 
parts  of  octaedral  crystals  of  alum  be 
entirely  decomposed  by  succinate  of  am- 
monia, they  give  precisely  12  parts  of  alu- 
mine calcined  in  a  dull  red  heat.  The 
succinate  of  ammonia,  it  is  stated  by  Mr. 
Ekeberg  (Journ.  des  Mines,  No.  70.)  pre- 
cipitates glucine ;  and  the  same  test,  ac- 
cording to  Klaproth,  (II,  214.)  throws 
down  zircon  from  its  solutions. 

XVIFT.  Phosphate  of  Soda. 
An  easy  and  valuable  method  of  preci- 
pitating magnesia  has  been  suggested  by 
Dr.  Wollaston.  It  is  founded  on  the  pro- 
perty which  fully  neutralized  carbonate 
of  ammonia  possesses ;  first  to  dissolve 
the  carbonate  of  magnesia,  formed  when 
it  is  added  to  the  solution  of  a  magnesian 
salt,  and  afterwards  to  yield  the  earth  to 
phosphoric  acid,  with  which  and  ammo- 
nia it  forms  a  triple  salt  For  this  pur- 
pose, a  solution  of  carbonate  of  ammonia, 
prepared  with  a  portion  of  that  salt  which 
has  been  exposed,  spread  on  a  paper,  for 
a  few  hours  to  the  air,  is  to  be  added  to 
the  solution  of  the  magnesian  salt  suffi- 
ciently concentrated ;  or  to  a  water  sus- 
pected to  contain  magnesia,  after  being 
very  much  reduced  by  evaporation.  No 
precipitate  will  appear,  till  a  solution  of 
phosphate  of  soda  is  added,  when  an 


abundant  one  will  fall  down.  Let  this  be 
dried  in  a  temperature  not  exceeding  100 
degrees  of  Fahrenheit.  One  hundred  grs. 
of  it  will  indicate  19  of  pure  magnesia,  or 
about  64  of  muriate  of  magnesia. 

XIX.  Muriate  of  Lime. 

Muriate  of  lime  is  principally  of  use  in 
discovering  the  presence  of  alkaline  car- 
bonates,  which  though  they  very  rarely 
occur,  have  sometimes  been  found  in  mi- 
neral waters.  Carbonate  of  potash  exists 
in  the  waters  of  Aix-la-Chapelle  ;  that  of 
soda,  in  the  water  of  a  few  springs  and 
lakes  ;  and  the  ammoniacal  carbonate  was 
detected  by  Mr.  Cavendish  in  the  waters 
of"  Rathbone-place.  Of  all  the  three  car- 
bonates, muriate  of  lime  is  a  sufficient  in- 
dicator ;  for  those  salts  separate  from  it  a 
carbonate  of  lime,  soluble  with  efferves- 
cence in  muriatic  acid. 

With  respect  to  the  discrimination  of 
the  different  alkalies,  potash  may  be  de- 
tected by  the  nitro  muriate  of  platina, 
which  distinctly  and  immediately  precipi- 
tates that  alkali  and  its  compounds,  and 
is  not  affected  by  soda.  Carbonate  of  am- 
monia may  be  discovered  by  its  smell,  and 
by  its  precipitating  a  neutral  salt  of  alu- 
mine, while  it  has  no  action  apparently  on 
magnesian  salts. 

To  estimate  the  proportion  of  an  alka- 
line carbonate  present  in  any  water,  satu- 
rate with  sulphuric  acid,  and  note  the 
weight  of  real  acid  which  is  required. 
Now  100  grains  of  real  sulphuric  acid  sa- 
turate 121.43  potash,  and  78.32  soda. 

XX.  Solution  of  Soap  in  Alcohol. 

This  solution  may  be  employed  to  as- 
certain the  comparative  hardness  of  wa- 
ters. With  distilled  water  it  may  be  mix- 
ed, without  any  change  ensuing;  but  if 
added  to  a  hard  water,  it  produces  a 
milkincss,  more  considerable  as  the  water 
is  less  pure  ;  and,  from  the  degree  of  this 
milkiness,  an  experienced  eye  will  derive 
a  tolerable  indication  of  the  quality  of  the 
water.  This  effect  is  owing'  to  the  alkali 
quitting  the  oil,  whenever  there  is  present 
in  a  water  any  substance,  for  which  the 
alkali  has  a  stronger  affinity  than  it  has 
for  oil.  Thus  all  uncombined  acids,  and 
all  earthy  and  metallic  salts,  decompose 
soap,  and  occasion  that  property  in  wa- 
ters which  is  termed  hardness. 

XXI.  Alcohol. 
Alcohol,  when  mixed  with  any  water, 
in  the  proportion  of  about  an  equal  bulk, 
precipitates  all  the  salts  which  it  is  inca- 
pable of  dissolving.  (See  Kirwan  on  Wa- 
ters, p.  263.) 


TES 

XXII.  Hydro-sulphuret  of  Ammonia. 

This  and  other  sulphurets,  as  well  as 
water  saturated  with  sulphuretted  hydro- 
gen, may  be  employed  in  detecting-  lead 
and  arsenic;  with  the  former  of  which 
they  give  a  black,  and  with  the  latter  a 
yellowish  precipitate.  As  lead  and  arse- 
nic, however,  are  never  found  in  natural 
waters,  I  shall  reserve,  for  another  occa- 
sion, what  I  have  to  say  on  the  application 
of  these  tests. 

TABLE, 

Showing  the  Substances  that  may  be  expect- 
ed in  Mineral  tVaters,  and  the  Means  of 
detecting  them. 

Acids,  in  general.  Infusion  of  litmus. — 
Syrup  of  violets,  I. 

Acid,  boracic.    Acetate  of  lead,  XIII.  3. 

Acid,  carbonic.  Infusion  of  litmus,  I.  1. 
2.— Lime-water,  VII.  1. — Barytic  water, 
IX.  1. 

Acid  muriatic.  Nitrate  and  acetite  of 
silver,  XII. 

Acid,  nitric.    Sulphuric  acid,  TV.  4. 
Acid,  phosphoric.    Solutions  of  barytes, 

XV.  2. 

Acid,  sulphurous.  By  its  smell, — and 
destroying-  the  colour  of  litmus,  and  of  in- 
fusion of  red  roses :  by  the  cessation  of 
the  smell  a  few  hours  after  the  addition  of 
black  oxyd  of  manganese. 

Acid,  sulphuric.  Solution  of  pure  ba- 
rvtes,  IX.  Barytic  salts,  XV  Acetite  of 
lead,  XII. 

Alkalies  in  general.  Vegetable  colours, 
II.    Muriate  of  lime,  XIX. 

Ammonia,  by  its  smell,  and  tests,  II. 

Barytes,  and  its  compounds,  by  sulphu- 
ric acid,  IV. 

Carbonates  in  general.  Effervesce  on 
adding  acids. 

Earths  dissolved  by  carbonic  acid.  By  a 
precipitation  on  boiling-, — bv  pure  alka- 
lies, VII. 

Iron  dissolved  by  carbonic  acid  Tinc- 
ture of  galls,  III  1.    Prussiate  of  potash, 

XVI.  1.    Succinate  of  ammonia,  XVII. 
Iron  dissolved  by  sulphuric  acid.  Same 

tests,  III.  3.  XVI.  2.  XVII. 

Lime  in  a  pure  state.  Water  saturated 
with  carbonic  acid  Blowing-  air  from  the 
lungs.    Oxalic  acid,  VI. 

Lime  dissolved  by  carbonic  acid.  Preci- 
pitation on  boiling. — Caustic  alkalies,  VII. 
Oxalic  acid,  VI. 

Lime  dissolved  by  sulphuric  acid.  Oxa- 
late of  ammonia,  VI.  Barytic  solutions, 
IX.  and  XV. 

Magnesia  dissolved  by  carbonic  acid  — 
Precipitation  on  boiling, — the  precipitate 
soluble  in  dilute  sulphuric  acid. 


TES 

Magnesia  dissolved  by  other  acids.  Pre 
cipitated  by  pure  ammonia,  not  by  the 
carbonate,  VII.  5.  Phosphate  of  soda, 
XVII. 

Muriates  of  alkalies.  Solutions  of  sil- 
ver, XII. 

Muriates  of  lime.  Solutions  of  silver, 
XII.  Oxalid  acid,  and  oxalate  of  ammo- 
nia, VI. 

Sulphates  in  general.  Barytic  solutions, 
IX.  and  XV.    Acetite  of  lead,  XIII. 

Sulphate  of  alumine.  Barytic  solutions, 
IX.  and  XV. — A  precipitate  by  carbonate 
of  ammonia  not  soluble  in  acetous  acid, 
but  soluble  in  pure  fixed  alkalies  by  boil- 
ing.   Succinates,  XVII  2. 

Sulphate  of  lime.    Barytic  solutions, 

IX.  and  XV  — Oxalic  acid,  and  oxalates, 
VI. — A  precipitate  by  alkalies  not  soluble 
in  dilute  sulphuric  acid. 

Sulphurets  of  alkalies.  Polished  metals, 

X.  Smell  on  adding  sulphuric  or  muria- 
tic acid — Nitrous  acid,  V. 

Sulphuretted  hydrogen  gas.  By  its  smell. 
Infusion  of  litmus,  I.  Polished  metals,  X. 
Acetite  of  lead,  XIII.  2. 

The  vapour  of  putrefying  animal  or 
vegetable  maiter  dissolved  in  water,  ac- 
cording to  Klaproth,  vol.  i,  p.  590,  often 
gives  a  deceptive  indication  of  sulphuret- 
ted hydrogen. 

Besides  the  remarks  already  offered,  it 
may  not  be  improper  to  add,  for  the  in- 
formation of  our  readers,  the  following 
list  of  re-agents,  together  with  the  neces- 
sary fluxes  for  the  blow-pipe,  which  we 
have  extracted  from  a  publication,  entitled 
"  A  description  of  a  portable  chest  of  che- 
mistry ;  or  a  complete  collection  of  che- 
mical tests  for  the  use  of  chemists,  phy- 
sicians, mineralogists,  metallurgists,  sci- 
entific artists,  manufacturers, farmers,  &c. 
by  J.  F.  A.  Gottling,  of  Jena,  in  Saxony, 
translated  from  the  German, 1791, 12mo." 
This  book  describes  more  than  150  expe- 
riments, and  which  the  young  practioner 
should  consult  at  the  time  of  commencing 
his  operations. 

First  Draper. 

1  Tincture  of  Litmus. 

2.  Lixivium  of  Prussian  blue. 

3.  Vitriolic  acid. 

4.  Nitrous  acid. 

5.  Marine  acid. 

6.  Acetous  acid. 

7.  Mild  volatile  alkali. 

8.  Mild  vegetable  alkali. 

9.  Highly  rectified  spirit  of  wine. 

10.  Lime-water. 

11.  Distilled  water. 

12.  Calcareous  liver  of  sulphur. 

13.  Crystals  of  tartar  in  powder. 


TES 


TES 


14.  A  phial  containing  a  wine-test  for 

detecting  bad  wines. 

15.  Vitriolic  argilla  (alum.) 

16.  Oil  of  olives. 

17.  Oil  of  linseed. 

18.  Oil  of  turpentine. 

19.  Ether. 

20.  Acid  of  sugar. 

21.  Solution  of  alum. 

22.  Oil  of  tartar  per  deliquium. 

23.  Salt  of  tartar. 

24.  Aqua  regia  for  gold,  two  nitre  and 

one  marine. 

25.  Aqua  regia  for  platina,  half  marine 

and  half  nitrous  acid. 
The  three  following  are  the  most  es- 
teemed fluxes,  to  be  used  with  the  blow- 
pipe. 

26.  Dry  mineral  alkali. 

27.  Glass  of  borax. 

28.  f  Jlaciacal  acid  of  phosphorus. 

29.  Nitre  powdered. 

30.  Red  tartar  powdered. 

31.  White  arsenic. 

32.  Vitriol  of  iron,  and  copper. 

Second  Drawer. 

1.  Caustic  vegetable  alkali. 

2.  Caustic  volatile  alkali. 

3.  A  solution  of  lead  in  acetous  acid. 

4.  A  solution  of  soap. 

5.  A  solution  of  arsenic. 

6.  A  solution  of  corrosive  sublimate 

in  distilled  water. 

7.  A  solution  of  mercury  in  nitrious 

acid,  prepared  with  heat. 

8.  A  solution  of  mercury  in  nitrous 

acid,  prepared  without  heat. 

9.  Volatile  liver  of  sulphur. 

10.  Spirituous  tincture  of  galls. 

11.  Ponderous  earth  dissolved  in  ma- 

rine acid. 

12.  Nitrous  solution  of  silver. 

13.  Nitrous  solution  of  copper. 

14.  Purified  sal-ammoniac. 

15.  Purified  Epsom-salt. 

16.  A  solution  of  vitriol  in  copper. 

17.  Cuprum  ammoniacum. 

18.  Quicksilver. 

19.  Mineral  alkali. 

20.  Calcined  borax. 

21.  Fusible  salt  of  urine. 

22.  Essential  salt  of  wild  sorrel. 

23.  Salited  lime. 

24.  Sugar  of  lead. 

25.  Tincture  of  turmeric. 

26.  Tincture  of  Brazil  wood. 

7  o  the  preceding  are  added  prepared  pa- 
pers, viz. 

1.  Litmus  paper. 

2.  Brazil  wood  paper, 

3.  Turmeric  paper. 


4.  Litmus  paper  reddened  with  vine- 
gar. 

And  occasionally  are  packed  with  the 
same  apparatus,  two  cylindrical  glass 
cups,  to  exhibit  the  operations  by  ;  two 
or  three  glass  mattrasses,  to  contain  the 
substances  with  their  solvents  over  the 
(ire ;  a  small  glass  funnel,  a  small  porce- 
lain pestle  and  mortar,  one  or  two  small 
crucibles,  a  wooden  trough  to  wash  the 
ground  ores ;  some  sticks  of  glass,  and 
other  small  articles  convenient  in  the  pro- 
cesses. 

The  above  constitute  what  has  been 
called  the  humid  laboratory.  A  blow- 
pipe with  fluxes,  silver  spoon,  and  other 
uselul  mineralogical  implements,  are 
packed  into  a  pocket  fish-skin  case,  and 
are  called  the  dry  laboratory. 

In  a  small  tract  published  by  Mr.  F. 
Accum,  we  have  a  catalogue  of  re-agents, 
Which  are  selected  from  a  number,  adapt- 
ed to  the  analysis  of  ores,  earths,  and 
stones,  sails,  mineral  and  native  salts,  and 
inflammable  fossils,  viz,. 

List  of  Chemical  re-agents,  or  te&te. 
Sulphuric  acid. 
Nitric  acid. 
Muriatic  acid. 
Nitro-muriatic  acid. 
Oxygenized  muriatic  acid. 
Phosphoric  acid. 
Acetous  acid. 
Tartareous  acid. 
Boracic  acid. 
Crystallized  potash. 

soda, 
barytes. 
Liquid  ammonia. 
Carbonate  cf  potash. 
Carbonate  of  soda  freed  from  its  wa-  ' 
ter  of  crystallization. 
Muriate  of  tin. 

platina. 
gold, 
barytes. 
mercury, 
ammonia. 
Nitrate  of  lead. 

mercury, 
silver, 
potash, 
barytes. 
Barytic  water. 
Sulphate  of  potash. 

soda, 
iron. 

Alcohol. 

Tincture  of  galls. 

turmeric. 

litmus. 
Prussiate  of  potash. 
Black  flux. 


TES 


TES 


White  flux. 
Oxalate  of  ammonia. 
Tluate  of  ammonia. 
Acetite  of  silver. 
Hydro-sulphuret  of  ammonia. 
Phosphate  of  soda  and  ammonia.. 
Cylinders  of  copper. 

tin. 

zinc. 

iron. 

As  a  short  account  of  the  analysis  of  in- 
flammable fossils  and  ores,  may  be  use- 
ful to  the  reader,  we  extract  the  following- 
observations  from  Henry's  Chemistv,  8vo. 
p.  352  I 

Analysis  of  Inflammable  Fossils. 
The  exact  analysis  of  inflammable  fos- 
sils is  seldom  necessary,  in  directing'  the 
most  beneficial  application  of  them.  It 
may  be  proper,  however,  to  offer  a  few 
general  rules  for  judging- of  their  purity. 

I.  Sulphur. 

Sulphur  should  be  entirely  volatilzed 
by  distillation,  in  a  glass  retort.  If  any 
thing  remain  fixed,  it  must  be  considered 
as  an  impurity,  and  may  be  examined  by 
the  preceding  rules. 

Sulphur,  also,  should  be  totally  dissolv- 
ed by  boiling  with  solution  of  pure  pot 
ash,  and  may  be  separated  from  its  impu- 
rities by  this  alkali. 

Impure  sulphur,  consumed  by  burning 
in  a  small  crucible,  leaves  a  residue  of 
oxide  of  iron,  and  silex. 

II.  Coals. 

1.  The  proportion  of  bituminous  matter 
in  coal,  may  be  learnt  by  distillation,  in  an 

*  earthen  retort,  and  collecting  their  pro- 
duct. 

2.  The  proportion  of  earth)-  or  metal- 
lic ingredients  may  be  found,  by  burning 
the  coal,  with  access  of  air,  on  a  red-hot 
iron.  What  remains  unconsumed  must 
be  considered  as  an  impurity,  and  may  be 
analized  by  the  foregoing  rules. 

3.  The  proportion  of  carbon  may  be 
ascertained  by  observing  the  quantity  of 
nitrate  of  potash,  which  a  given  weight 
of  the  coal  is  capable  of  decomposing. — 
For  this  purpose,  let  500  grains  or  more, 
of  perfectly  pure  nitre  be  melted  in  a  cru- 
cible, and  when  red-hot,  let  the  coal  to 
be  examined,  reduced  to  a  coarse  powder, 
be  projected  on  the  nitre,  by  small  por- 
tions at  once,  not  exceeding  one  or  two 
grains.  Immediately!  when  the  fiame, 
occasioned  by  one  projection,  has  ceased, 
let  another  be  made,  and  so  on,  till  the 
effect  ceases.  The  proportion  of  carbon 
in  the  coal,  is  directly  proportionate  to  the 


quantity  required  to  alkalize  the  nitre.— 
Thus,  since  12.709  of  carbon  are  re- 
quired to  alkalize  100  of  nitre,  it  will  be 
easy  to  deduce  the  quantity  of  carbon,  in 
a  given  weight  of  coal,  from  the  quantity 
of  nitre  which  it  is  capable  of  decompos- 
ing. This  method,  however,  is  liable  to 
several  objections,  which  its  inventor,  Mr. 
Kirwan,  seems  fully  aware  of.  See  his 
Elements  of  Mineralogy,  vol.  ii.  p.  514. 

Plumbago,  or  Black-lead. 
Is  another  inflammble  substance,  which 
it  may  sometimes  be  highly  useful,  to  be 
able  to  identify,  and  to  judge  of  its  puri 
ty.  When  projected  on  red-hot  nitre,  it 
should  detonate  ;  and,  on  dissolving  the 
decomposed  nitre,  an  oxide  of  iron  should 
remain,  amounting  to  one-tenth  the  weight 
or"  the  plumbago.  Any  mineral,  therefore, 
that  answers  to  these  characters,  and 
leaves  a  shining  trace  on  paper,  like  that 
of  the  black-lead  pencils,  is  plumbago. 

Analysis  of  Metallic  Ores. 

The  class  of  metals  comprehends  so 
great  a  number  of  individuals,  that  it  is 
almost  impossible  to  offer  a  comprehen- 
sive formula,  for  the  analysis  of  ores. — 
Ores  of  the  same  metal,  also,  as  the  mine 
ralizing  ingredients  vary,  require  very- 
different  treatment.  Yet  some  general 
directions  are  absolutely  necessary,  to 
enable  the  naturalist  to  judge  of  the  com- 
position of  bodies  of  this  class 

The  ores  of  metals  may  be  analized  in 
two  modes,  in  the  humid  and  the  dry  way. 
The  first  is  effected  with  the  aid  of  acids, 
and  other  liquid  agents,  and  may  often  be 
accomplished  by  persons  who  are  prevent- 
ed, by  the  want  of  furnaces,  and  other  ne- 
cessary apparatus,  from  attempting  the 
second.  If  sulphur,  however,  be  present 
in  an  ore,  which  may  be  generally  known 
by  its  external  characters,  as  described 
by  mineralogical  writers,  it  impedes  the 
action  of  scids;  and  should  be  separated, 
either  by  roasting  the  ore  on  a  muflfie,  or 
by  projecting  it,mixed  with  twice  or  thrice 
its  weight  of  nitre  into  a  red-hot  cruci- 
ble, washihg  off  the  alkali  afterwards,  by 
hot  water. 

It  is  hardly  possible  to  employ  a  solvent, 
capable  of  taking  up  all  the  metals.  Thus, 
the  nitric  acid  does  not  act  on  gold  or 
pLatina ;  and  the  nitro-muriatic,  which 
dissolves  these  metals,  has  no  solvent  ac- 
tion on  silver.  It  will  be  necessary,  there- 
fore, to  vary  the  solvent  according  to  the 
nature  of  the  ore  under  examination. 

1  For  Ores  of  Gold  and  Platina- 
The  nitro-muriatic  acid  is  the  most  pro- 
per solvent.    A  given  weight  of  the  ore 


TES 


TES 


may  be  digested  with  this  acid,  as  long  as 
it  extracts  any  thing.  The  solution  may  be 
evaporated  to  dryness,  in  order  to  expel 
the  excess  of  acid,  and  dissolved  in  water. 
The  addition  of  a  solution  of  tin  and  mu- 
riatic acid,  will  shew  the  presence  of  gold 
by  apurple  precipitate;  and  platina  will  be 
indicated  by  a  precipitate,  on  adding  a  so- 
lution  of  muriate  of  ammonia.  When  gold 
and  platina  are  both  contained  in  the  same 
solution,  they  may  be  separated  from  each 
other,  by  the  last  mentioned  solution, 
which  throws  down  the  platina,  but  not 
the  gold.  In  this  way  platina  may  be  de- 
tached, also,  from  other  metals. 

When  gold  is  contained  in  a  solution, 
along  with  several  other  metals,  it  may 
be  separated  from  most  of  them,  by  add  - 
ing a  dilute  solution  of  sulphate  of  iron. 
The  only  metals,  which  this  salt  precipi- 
tates, are  gold,  palladium,  silver  and  mer- 
cury. 

2.  For  extracting  silver  from  its  ores, 
the  nitric  acid  is  the  most  proper  solvent. 
Nitric  acid,  however,  does  not  act  on  horn- 
silver  ore,  which  must  be  decomposed  by 
carbonate  of  soda.  The  silver  may  be 
precipitated  from  nitric  acid,  by  muriate 
of  soda,  (common  salt.)  Every  hundred 
parts  of  the  precipitate  contains  75  of  sil- 
ver. But,  as  lead  may  be  present  in  the 
solution,  and  this  metal  is  also  precipi- 
tated by  muriate  of  soda,  it  may  be  pro- 
per to  immerse  in  the  solution,  (which 
should  not  have  any  excess  of  acid,)  a 
polished  plate  of  copper.  This  will  pre- 
cipitate the  silver,  if  present,  in  a  metallic 
form.  The  muriate  of  silver  is  also  solu- 
ble in  liquid  ammonia,  which  that  of  lead 
is  not.  For  examples  of  the  analysis  of 
silver  ores,  the  reader  may  consult  Klap- 
roth,  i.  p.  554,  Sec. 

3.  Copper  Ores  may  be  analized  by  boil- 
ing them  with  five  times  their  weight,  of 
concentrated  sulphuric  acid,  till  a  dry 
mass  is  obtained,  from  which  water  will 
extract  the  sulphate  of  copper.  This  salt 
is  to  be  decomposed  by  a  polished  plate 
of  iron,  immersed  in  a  dilute  solution  of 
it.  The  copper  will  be  precipitated  in  a 
metallic  state,  and  may  be  scraped  off  and 
weighed; 

If  silver  be  suspected  along  with  cop- 
per, nitrous  acid  must  be  employed  as  the 
solve.*;  and  a  plate  of  polished  copper 
will  detect  the  silver. 

The  reader,  who  engages  in  the  analy- 
sis of  copper  ores,  will  derive  much  ad- 
vantage from  the  examples  to  be  found  in 
Klaproths'  Essays,  vol.  i.  p.  54,  541,  &c. ; 
and  also  from  Mr.  Chenevix's  paper  on 
the  analysis  of  arseniates  of  copper  and 
?.ron,  Phil.  Trans.  1801 ;  Nicholson's  Jour- 
nal, 8vo.  vol.  i.  ;  or  Phil.  Mag. 

VOL.  II. 


4.  Iron  ores  may  be  dissolved  in  dilute 
muriatic  acid,  or,  if  the  metal  be  too 
highly  oxydized,  to  be  dissolved  by  this 
acid,  they  must  be  previously  mixed  with 
one-eighth  of  their  weight  of  powdered 
charcoal,  and  calcined  in  a  crucible  forone 
hour.    The  iron  is  thus  rendered  soluble. 

The  solution  must  then  be  diluted  with 
ten  or  twelve  times  its  quantity  of  water, 
previously  well  boiled,  to  expel  the  air, 
and  must  be  preserved  in  a  well-stopped 
glass  bottle  for  six  or  eight  days.  The 
phosphate  of  iron  will,  within  that  time, 
be  precipitated,  if  any  be  present,  and  the 
liquor  must  be  decanted  off. 

The  solution  may  contain  the  oxides  of 
iron,  manganese  and  zinc.  It  may  be  pre- 
cipitated by  carbonate  of  soda,  which  will 
separate  them  all.  The  oxide  of  zinc  will 
be  taken  up  by  a  solution  of  pure  ammo- 
nia; distilled  vinegar  will  take  up  the 
manganese,  and  will  leave  the  oxide  of 
iron.  From  the  weight  of  this,  after  igni- 
tion, during  a  quarter  of  an  hour,  28  per 
cent,  may  be  deducted.  The  remainder 
shows  the  quantity  of  iron. 

5.  Tin  ores.  To  that  most  accomplish- 
ed analyst,  Klaproth,  we  owe  the  disco, 
very  of  a  simple  and  effectual  mode  of 
analizing  tin  ores  in  the  humid  way. 

Boil  100  grains,  in  a  silver  vessel,  with 
a  solution  of  600  grains  of  pure  potash. — 
Evaporate  to  dryness,  and  then  ignite, 
moderately,  for  half  an  hour.  Add'  boil- 
ing water,  and  if  any  portion  remain  un- 
dissolved, let  it  undergo  a  similar  treat- 
ment. 

Saturate  the  alkaline  solution  with  mu- 
riatic acid,  which  will  throw  down  an  ox- 
ide of  tin.  Let  this  be  redissolved  by  an 
excess  of  muriatic  acid ;  again  precipitated 
by  carbonate  of  soda ;  and,  being  dried 
and  weighed,  let  it,  after  lixiviation,  br 
once  more  dissolved  in  muriatic  acid. 
The  insoluble  part  consists  of  silex.  Into 
the  colourless  solution,  diluted  with  two 
or  three  parts  of  water,  put  a  stick  of 
zinc,  round  which  the  reduced  tin  will 
collect.  Scrape  off  the  deposit,  wash, 
dry,  and  fuse  it  under  a  cover  of  tallow 
in  a  capsule  placed  on  charcoal.  A  but- 
ton of  pure  metallic  tin  will  remain  at  the 
bottom,  the  weight  of  which,  deducted 
from  that  of  the  ore,  indicates  the  propor- 
tion of  oxygen. 

The  presence  of  tin  in  an  ore  is  indica- 
ted by  a  purple  precipitate,  on  mixing  its 
solutoin  in  muriatic  ac  id  with  one  of  gold 
in  nitro-muriatic  acid. 

6.  Lead  ores  may  be  analyzed  by  solu- 
tion in  nitric  acid,  diluted  with  an  equal 
weight  of  water.  The  sulphur,  if  any, 
will  remain  undissolved.  Let  the  solution 
be  precipitated  by  carbonate  of  soda.  If 

3  N 


TES 


TES 


any  silver  be  present,  it  will  be  taken  up 
by  pure  liquid  ammonia.  Wash  off  the 
excess  of  ammonia  by  distilled  water; 
and  add  concentrated,  sulphuric  acid,  ap- 
plying- heat,  so  that  the  muriatic  acid 
may  be  wholly  expelled.  Weigh  the  sul- 
phate of  lead,  and,  after  deducting-  70 
per  cent,  the  remainder  shows  the  quan- 
tity of  lead. 

Muriate  of  lead  may  also  be  separated 
from  muriate  of  silver  by  its  greater  solu- 
bility in  warm  water.  From  the  solution, 
iron  may  be  separated  by  prussiate  of  pot- 
ash, and  tiie  solution  decomposed  by  sul- 
phuric acid. 

7.  Mercury  may  be  detected  in  ores 
that  are  supposed  to  contain  it,  by  distil- 
lation in  an  earthen  retort  with  half  their 
weight  of  iron  filings  or  lime.  The  mer- 
cury, if  any  be  present,  will  rise  and  be 
condensed  in  the  receiver. 

8.  Ores  of  Zinc  may  be  digested  with 
the  nitric  acid,  and  the  part  that  is  dis- 
solved boiled  to  dryness,  again  dissolved 
in  the  acid,  and  again  evaporated.  By 
this  means  the  iron,  if  any  be  present, 
will  be  rendered  insoluble  in  dilute  nitric 
acid,  which  will  take  up  the  oxide  of  zinc. 
To  this  solution  add  pave  liquid  ammonia, 
in  excess,  which  vviil  separate  the  lead 
and  iron,  if  any  should  have  been  dissolv- 
ed ;  and  the  excess  of  alkali  will  retain 
the  oxide  of  zinc-  This  may  be  separated 
by  the  addition  of  an  acid. 

9-  Antivrwnial  ores.  Dissolve  a  given 
weight,  in  three  or  lour  parts  of  muriatic 
and  one  of  nitric  acid.  This  will  take  up 
the  antimony,  and  ieave  the  sulphur,  if 
any.  On  dilution  with  water,  the  oxide 
of  antimony  is  precipitated,  and  the  iron 
and  mercury  remain  dissolved.  Lead  may- 
be detected  by  sulphuric  acid.  See  Kla- 
proth  on  the  Analysis  of  Antimoniated 
Silver  Ore,  I,  p.  560. 

10.  Ores  of  arsenic  may  be  digested 
u  ith  nitro-muriatic  acid,  composed  of  one 
part  nitric,  and  one  and  a  half  or  two  or 
muriatic  acids.  Evaporate  the  solution 
to  one  fourth,  and  add  water,  which  will 
precipitate  the  arsenic-  The  iron  may  af- 
terwards be  separated  by  ammonia.  See 
(Jhenevix,  Phil.  Trans.  1801,  p.  215. 

11.  Ores  of  bismuth  are  also  assayed  by 
digestion  in  nitric  acid  moderately  dilu- 
ted. The  addition  of  water  precipitates 
the  oxide,  and,  it  not  wholly  separated  at 
first,  evaporate  the  solution  ;  after  which, 
a  farther  addition  of  water  will  precipitate 
the  remainder.  See  Analysis  of  an  Ore  of 
Bismuth  and  Silver,  in  Kiaproth,I,  p.  554. 
Mode  of  detecting  a  small  Quantity  of 
Silver  in  Bismuth,  ditto;  p.  220,  c. 

12.  Ores  of  cobalt  maV  be  dissolved  in 


nitro-nmriatic  acid.  Then  add  carbonate 
of  potash,  which,  at  first,  separates  iron 
and  arsenic.  Filter,  and  add  a  farther 
quantity  of  the  carbonate,  when  a  grey- 
ish red  precipitate  will  fall  down,  which 
is  oxide  of  cobalt.  The  iron  and  arsenic 
may  be  separated  by  heat,  which  volati- 
lizes the  arsenic.  Cobalt  is  also  ascer- 
tained, if  the  solution  of  an  ore  in  muriatic 
acid  gives  a  sympathetic  ink.  See  Chap, 
xix,  sect  IS.  An  example  of  the  analysis 
of  an  ore  of  cobalt  may  be  seen  in  Kla- 
proth,  I,  p.  5G4,  and  sulphate  of  cobalt, 
p.  579. 

13.  Ores  of  nickel.  Dissolve  them  in 
nitric  acid,  and  add  to  the  solution  pure 
ammonia,  in  such  proportion  that  the  al- 
kali may  be  considerably  in  excess.  This 
will  precipitate  other  metals,  and  will  re- 
tain the  oxide  of  nickel  in  solution,  which 
may  be  obtained  by  evaporation  to  dry- 
ness, and  heating  the  dry  mass  till  the  ni- 
trate of  ammonia  has  sublimed. 

14.  Ores  of  manganese .  The  earths,  and 
several  of  the  metals,  contained  in  these 
ores,  may  first  be  separated  by  diluted 
nitric  acid,  which  does  not  act  on  highly 
oxydized  manganese.  The  ore  may  af- 
terward be  digested  with  strong  muriatic 
acid,  which  will  take  up  the  oxide  of 
manganese.  Oxygenized  muriatic  acid 
will  arise,  if  a  gentle  heat  be  applied,  and 
may  be  known  by  its  peculiar  smell,  and 
by  its  discharging  the  colour  of  wet  lit- 
mus paper  exposed  to  the  fumes.  From 
muriatic  acid  the  manganese  is  precipi- 
tated by  carbonate  of  soda,  in  the  form  of 
a  white  oxide,  which  becomes  black  when 
heated  in  a  crucible.  Ores,  suspected  to 
contain  manganese,  may  also  be  distilled 
per  se^  or  with  sulphuric  acid,  when  oxy- 
gen gas  will  be  obtained.  Oxide  of  man- 
ganese may  be  separated  from  oxide  of 
iron  by  solution  of  pure  potash,  which 
takes  up  the  former  but  not  the  latter. 
See  the  analysis  of  an  ore  of  manganese, 
•via  huniida,  in  Klaproth,  I,  p.  510;  and  of 
a  cobaltic  ore  of  manganese,  p.  569. 

Ores  of  manganese  may  also  be  distin- 
guished by  the  colour  they  impart  to  bo- 
rax, when  exposed  together  to  the  blow- 
pipe. 

15.  Ores  of  Uranium.  These  may  be 
dissolved  in  dilute  nitric  acid,  which  takes 
up  the  uranitic  oxide,  and  leaves  .hat  of 
iron ;  or  in  dilute  sulphuric  acid,  which 
makes  the  same  election  ;  or,  if  any  iron 
has  got  into  the  solution,  it  may  be  preci- 
pitated by  zinc.  Then  add  caustic  pot- 
ash, which  throws  down  the  oxide  of  zinc 
and  uranium.  The  former  may  be  sepa* 
rated  by  digestion  in  pure  ammonia, 
which  leaves,  undissolved,  the  oxide  or 


TES 


TES 


uranium.  This,  when  dissolved  by  dilute 
sulphuric  acid,  affords,  on  evaporation, 
crystals  of  a  lemon-yellow  colour. 

If  copper  be  present,  it  will  be  dissolv- 
ed, along-  with  the  zinc,  by  the  ammonia. 
If  lead,  it  will  form,  with  sulphuric  acid,  a 
salt  much  less  soluble  than  the  sulphate 
of  uranium,  and  which,  on  evaporation, 
will  therefore  separate  first. 

16.  Ores  of  tungsten.  For  these  the 
most  proper  treatment  seems  to  be  diges- 
tion in  nitro-muriatic  acid,  which  takes 
up  the  earths  and  other  metals.  The 
tungsten  remains  in  the  form  of  a  yellow 
oxide,  distinguishable,  by  its  becoming 
white  on  the  addition  of  liquid  ammonia, 
from  the  oxide  of  uranium.  To  reduce 
this  oxide  to  tungsten,  mix  it  with  an 
equal  weight  of  dried  blood,  heat  the  mix- 
ture to  redness,  press  it  into  another  cru- 
cible, which  should  be  nearly  full,  and  ap- 
ply a  violent  heat  for  an  hour  at  least. 

17.  Ores  of  molybdena.  Repeated  dis- 
tillation to  dryness,  with  nitric  acid,  con- 
verts the  oxide  into  an  acid,  w  hich  is  in- 
soluble in  nitric  acid,  and  may  be  ihus  se- 
parated from  other  metals,  except  iron, 
which  nfay  be  dissolved  by  sulphuric 
or  muriatic  acids.  The  solution  in  sul- 
phuric acid  is  blue,  when  cold,  but  co- 
lourless, when  heated.  That  in  muriatic 
acid  is  only  blue  when  the  acid  is  heated 
and  concentrated.  (See  Hatchett's  Analy- 
sis of  the  Carinthian  Molybdate  of  Lead, 
Phil.  Trans.  1796;  and  Klaproth,  vol.  I, 
p.  534.  538.) 

Respecting  the  ores  of  the  remaining 
metals,  sufficient  information  has  been  al- 
ready given  ;  and  they  are  of  such  rare  oc- 
currence, that  it  is  unnecessary  for  us  to 
describe  them  in  this  place.  It  may  be 
proper,  however,  to  State  where  the  "best 
examples  of  the  analysis  of  each  may  be 
found. 

18.  Ores  of  titanium.  Consult  Gregor, 
in  Journ.  de  Physique,  xxxix.  72-  152; 
Klaproth,  1.  496;  and  Chencvix,  Nich. 
Journ.  V.  132. 

19.  Ores  of  tellurium.  See  Klaproth, 
11,1. 

20-  Ores  of  tantalium.  Ann.  de  Chim. 
xliii.  276. 

21.  Ores  of  chromium.  Vauquelin, 
Ann.  de  Chim.  xxv. 

22.  Ores  of  columbium.  Hatchett,  Phil. 
Trans.  1802. 

23.  Ores  of  palladium  and  rhodium. 
Wollaston,  Phil.  Trans.  1805. 

24.  Ores  of  iridium  and  osmium.  Ten- 
nant,  Phil.  Trans.  1804. 

25.  Ores  of  cerium.  Hisenger  and  I3cr- 
zelius,  and  Vauquelin,  Nich.  Journ.  xii. 

Besides  the  information  given  in  the 


preceding  pages,  we  might  enumerate 
the  application  of  these  and  other  re- 
agents, to  the  purposes  of  the  physician, 
artist,  manufacturer,  farmer  and  the  do- 
mestic economist.  We  have  already  men- 
tioned their  use  in  the  discovery  of  poi- 
sons See  Poisons.  And  have  also,  on 
several  occasions,  given  their  miscellane- 
ous uses.  We  will  add,  however,  the  fol- 
lowing article,  which  we  have  taken  from 
the  same  excellent  work,  for  which  we 
were  originally  indebted  for  its  arrange- 
ment, to  Goetling  a  celebrated  German 
professor. 

RULES  FOR  ASCERTAINING  THE  PURI- 
TY OF  CHEMICAL  PREPARATIONS, 
EMPLOYED  FOR  THE  PURPOSES  OF 
MEDI  CI  N  E,  AND  FOR  OTHER  USES. 

1.  Sulphuric  acid — Acidum  Vitriolicum  of 
the  London  Pharmacopoeia — Oil  of  Vi- 
triol. 

The  specific  gravity  of  sulphuric  acid 
should  be  18.50.  It  should  remain  per- 
fectly transparent  when  diluted  with  dis- 
tilled water.  If  a  se  diment  occur,  on  di* 
lution,  it  is  a  proof  of  ihe  presence  of  sul- 
phate of  lead  or  of  lime. 

Iron  may  be  detected  in  sulphuric  acid, 
by  sat  urating  a  diluted  portion  of  it  with 
pure  carbonate  of  soda,  and  adding  prus- 
siate  of  potash,  which  will  manifest  the 
presence  of  iron  by  a  prussian  blue  preci- 
pitate ;  or  it  will  be  discovered  by  a  pur- 
plish or  blackish  tinge,  on  the  addition  of 
tincture  of  galls  to  a  similarly  saturated 
portion.  Copper  may  be  discovered,  by 
pouring,  into  a  similarly  saturated  solu- 
tion, pure  solution  of  ammonia;  and  lead 
may  be  detected  by  the  sulphuret  of  am- 
monia. The  latter  metal,  however,  is  ge- 
nerally precipitated,  on  dilution,  in  combi- 
nation with  sulphuric  acid. 

Sulphate  of  potash  or  of  soda  may  be 
found  by  saturating  the  diluted  acid  with 
ammonia,  evaporating  to  dryness,  and  ap- 
plying a  pretty  strong  heat.  The  sulphate 
of  ammonia  will  escape,  and  that  of  pot- 
ash or  of  soda  will  remain,  and  may  be 
distinguished  by  its  solubility  and  other 
characters. 

2.  Nitric  and  Nitrous  Acids. — Qcidum  Ni- 
trosum,  P/wrm.  Lond. — Aqua  Fortis. 
The  nitric  acid  should  be  perfectly  co- 
lourless, and  as  limpid  as  water.  It  should 
be  preserved  in  a  dark  place,  to  prevent 
its  conversion  into  the  nitrous  kind. 

These  acids  are  most  likely  to  be  adul- 
terated with  sulphuric  and  muriatic,  acids. 
The  sulphuric  acid  may  be  discovered  by 
adding  to  a  portion  of  the  acid,  largely 


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dilated,  nitrated  or  muriated  barytes, 
which  will  occasion,  with  sulphuric  acid, 
a  white*  and  insoluble  precipitate.  The 
muriatic  acid  may  be  ascertained  by  ni- 
trate of  silver,  which  affords  a  sediment, 
at  first  white,  but  which  becomes  colour- 
ed by  exposure  to  the  direct  light  of*  the 
sun.  Both  these  acids,  however,  may  be 
present  at  once ;  and,  in  this  case,  it  will 
be  necessity  to  add  a  solution  of  nitrate 
of  barytes,  as  long-  as  any  precipitate 
falls,  which  will  separate  the  sulphuric 
acid.  Let  the  sediment  subside,  decant 
the  clear  liquor,  and  add  the  nitrate  of 
silver.  If  a  precipitate  appear,  muriatic 
acid  may  be  interred  to  be  present  also. 
Muriatic  acid  may,  also,  be  detected  by- 
adding  a  solution  of  sulphate  of  silver. 

These  acids  should  have  the  specific 
gravity  of  1550. 

3.  JMuriatic  Acid — Acidum  Muriaticum, 

P  L. — Spirit  of  Salt. 

This  acid  generally  contains  iron,  which 
may  be  known  by  its  yellow  colour ;  the 
pure  acid  being  perfectly  colourless.  It 
may  also  be  detected  by  the  same  mode 
as  was  recommended  in  examining  sul- 
phuric acid. 

Sulphuric  acid  is  discoverable  by  a  pre- 
cipitation, on  adding  to  a  portion  of  the 
acid,  diluted  with  five  or  six  parts  of  pure 
water,  a  solution  of  the  muriate  of  ba- 
rytes. 

The  specific  gravity  of  this  acid  should 
be  at  least  1170. 

4.  Acetic  Acid— Acidum  Acetosum,  P.  L. 

— Radical  or  concentrated  Vinegar. 

This  acid  is  often  contaminated  by  sul- 
phurous and  sulphuric  acid.  The  first 
may  be  known  by  drawing  a  little  of  the 
vapour  into  the  lungs,  when,  if  the  acid 
be  pure,  no  unpleasant  sensation  will  be 
felt;  but,  if  sulphurous  acid  be  contained 
in  the  acetic,  it  will  not  fail  to  bt  discover- 
ed in  this  mode.  The  sulphuric  acid  is 
detected  by  muriated  barytes  ;  copper,  by 
supersaturation  with  pure  ammonia;  and 
lead,  by  sulphuretof  ammonia. 

The  specific  gravity  of  this  acid  should 
be  1060  at  least. 

5.  Acetous  Acid — Zcetum  Distillatum,  P. 

L. — Distilled  Vinegar. 
If  vinegar  be  distilled  in  copper  vessels, 
it  can  hardly  fail  being  contaminated  by 
that  metal ;  and,  if  a  leaden  worm  be  us- 
ed for  its  condensation,  some  portion  of 
lead  will  certainly  be  dissolved.  The  for- 
mer metal  will  appear  on  adding  an  ex- 
cess of  solution  of  pure  ammonia  ;  and 
lead  will  be  detected  by  the  sulphuretted 


ammonia,  or  by  water  saturated  with  sul- 
phuretted hydrogen. 

It  is  not  unusual,  in  order  to  increase 
the  acid  taste  of  vinegar,  to  add  sulphu- 
ric acid.  Tnis  acid  may  be  immediatel) 
discovered  by  solutions  of  barytes,  which, 
when  vinegar  has  been  thus  adulterated, 
throw  down  a  white  precipitate. 

6.  Boracic  Acid— Sedative  Salt  of  Rom- 
berg. 

Genuine  boracic  acid  should  totally  dis- 
solve in  five  times  its  weight  of  boiling 
alcohol :  and  the  solution,  when  set  on 
fire,  should  emit  a  green  flame.  The  best 
boracic  acid  forms  small  hexangular  sca- 
ly crystals  of  a  shining  silvery  white  co- 
lour.   Its  specific  gravity  is  1480- 

7.  Tartarous  Acid. 

Tins  acid  contains  sulphuric  acid;  to 
discover  which,  let  a  portion  be  dissolved 
in  water,  and  a  solution  of  acetite  of  lead 
be  added.  A  precipitate  will  appear, 
which,  if  the  acid  be  pure,  is  entirely  re- 
dissolved  by  a  few  drops  of  pure  nitric 
acid,  or  by  a  little  pure  acetic  acid.  If 
any  portion  remain  undissolved  sulphu- 
ric acid  is  the  cause.  Muriate  of  barytes, 
also,  when  the  acid  is  adulterated  with 
sulphuric  acid,  but  not  otherwise,  gives  a 
precipitate  insoluble  by  an  excess  of  mu- 
riatic acid. 

8.  Acid  of  Amber. 

Acid  of  amber  is  adulterated,  some 
times  with  sulphuric  acid  and  its  combi- 
nations ;  sometimes  with  tartarous  acid  , 
and  at  others  with  muriate  of  ammonia. 

Sulphuric  acid  is  detected  by  solutions 
of  barytes ;  tartarous  acid  by  carbonate 
of  potash,  which  forms  a  difficultly  solu- 
ble tart  rite  ;  and  muriate  of  ammonia  by- 
nitrate  of  silver j  which  discovers  the  acid, 
and  by  a  solution  of  pure  potash,  which 
excites  a  strong  smell  of  ammonia. 

Pure  acid  of  amber  is  a  crystalline 
white  salt  of  an  acid  taste,  soluble  in 
twenty -four  parts  of  cold,  or  eight  of  hoi 
water,  and  is  volatilized,  when  laid  on 
red-hot  iron,  without  leaving  any  ashes  or 
other  residue. 

9.  Acid  of  Benzoin — .Flores  Benzoes,  P.  L. 
This  acid  is  not  very  liaole  to  adultera- 
tion. The  best  has  a  brilliant  white  co- 
lour and  a  peculiarly  grateful  smell.  It 
is  soluble  in  a  large  quantity  of  boiling 
water  or  alcohol,  and  leaves  no  residue 
when  placed  on  a  heated  iron. 

10.  Sub-carbonate  of  Potash— Kali  Prepa- 

ratum-y  P.  L. 
The  salt  of  tartar  of  the  shops  gene- 


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rally  contains  sulphate  and  muriate  of  pot- 
ash, and  siliceous  and  calcareous  earths. 
It  should  dissolve  entirely,  if  pure,  in 
twice  its  weight  of  cold  water ;  and  any 
thing  that  remains  undissolved  may  be 
regarded  as  an  impurity.  Sometimes  one 
fourth  of  foreign  mixtures  may  thus  be 
detected,  the  greater  part  of  which  is 
sulphate  of  potash.  To  ascertain  the  na- 
ture of  the  adulteration,  dissolve  a  por- 
tion in  pure  and  diluted  nitric  acid :  the 
siliceous  earth  only  will  remain  undissolv- 
ed. Add,  to  one  portion  of  the  solution, 
nitrate  of  barvtes  ;  this  will  detect  sul- 
phate of  potash  by  a  copious  precipitate. 
To  another  portion  add  nitrate  of  silver, 
which  will  discover  muriatic  salts ;  and, 
to  a  third,  oxidate  or  filiate  of  ammonia, 
which  will  detect  calcareous  earth. 

The  solution  of  carbonate  of  potash 
{Aqua  Kali,  P.  L.)  may  be  examined  in  a 
similar  manner. 

11.  Solution  of  pure  Potash — ftqua  Kali 

Puri,  P.  L, 

This  may  be  assayed,  for  sulphuric  and 
muriatic  salts,  by  saturation  with  nitric 
acid,  and  by  the  tests  recommended  in 
speaking"  of  carbonate  of  potash.  A  per 
fectly  pure  solution  of  potash  should  re- 
main transparent  on  the  addition  of  bary- 
tic  water.  If  a  precipitate  should  ensue, 
which  dissolves  with  effervescence  in  di- 
lute muriatic  acid,  it  is  owing  to  the  pre- 
sence of  carbonic  acid  :  if  the  precipitate 
is  not  soluble,  it  indicates  sulphuric  acid. 
A  redundancy  of  carbonic  acid  is  also 
shown  by  an  effervescence,  on  adding  di- 
luted sulphuric  acid,  and  an  excess  of 
lime  by  a  white  precipitate,  on  blowing 
air  from  the  lungs,  through  the  solution, 
by  means  of  a  tobacco-pipe,  or  a  glass 
tube. 

The  solution  should  be  of  such  a 
strength,  as  that  an  exact  wine-pint  may 
weigh  18  ounces  troy. 

12.  Carbonate  of  Soda — Natron  Prepara- 

tum,  P.  L. 

Carbonate  of  soda  is  scarcely  ever  found 
free  from  muriate  and  sulphate  of  soda. 
These  may  be  discovered  by  adding,  to  a 
little  of  the  carbonate  saturated  with  pure 
nitric  acid,  first  nitrate  of  barvtes,  to  de- 
tect sulphuric  acid,  and  afterwards  ni- 
trate of  silver,  to  ascertain  the  presence 
of  muriatic  acid.  Carbonate  of  potash 
will  be  shown  by  a  precipitate  ensuing  on 
the  addition  of  tartarous  acid  to  a  strong 
solution  of  the  alkali ;  for,  this  acid  forms 
a  difficultly  soluble  salt  with  potash,  but 
not  with  soda, 


13.  Solution  of  Carbonate  of  Ammonia — 
Ac/ua  Ammoniac,  P.  L. 

This  should  have  the  specific  gravity  of 
1150  ;  should  effervesce  on  the  addition 
of  acids  ;  and  should  afford  a  strong  coa- 
gulum  on  adding  alcohol. 


14.  Carbonate  of  Ammonia — Ammonia 
Preparata,  P.  L. 

This  salt  should  be  entirely  volatilized 
bv  heat,  if  any  thing  remain,  when  it  is 
laid  on  a  heated  iron,  carbonate  of  potash 
or  of  lime  may  be  suspected ;  and  these 
impurities  are  most  likely  to  be  present  if 
the  carbonate  of  ammonia  be  purchased 
in  the  form  of  a  powder.  It  should  there- 
fore always  be  bought  in  solid  lumps. 
Sulphuric"  and  muriatic  salts,  lime  and 
iron,  may  be  discovered  by  adding  to  the 
alkali,  saturated  with  nitric  acid,  the  ap- 
propriate tests  already  often  mentioned. 

15.  Solution  of  pure  Ammonia  in  Water — 
Aqua  Ammonite  Puree,   P.  L. — Strong 

Spirit  of  Sal  Ammoniac. 

The  volatile  alkali,  in  its  purest  state, 
exists  as  a  gas  condensable  by  water,  and 
is  the  only  form  under  which  it  is  applica- 
ble to  useful  purposes.  This  solution 
should  contain  nothing  besides  the  vola- 
tile alkali ;  the  alkali  should  be  perfectly 
free  from  carbonic  acid,  and  should  be 
combined  with  water  in  the  greatest  pos- 
sible proportion.  The  presence  of  other 
salts  may  be  discovered  by  saturating  a 
portion  of  the  solution  with  pure  nitric 
acid,  and  adding  the  tests  for  sulphuric 
and  muriatic  acids.  Carbonic  acid  is 
shown  by  a  precipitation  on  mixing  the 
solution  with  one  of  muriate  of  lime;  for 
this  earthy  salt  is  not  precipitated  by  pure 
ammonia.  The  only  mode  of  delermin. 
ingthe  strength  of  the  solution  is  bytak. 
ing  its  specific  gravity,  which,  at  60°  Fah- 
renheit, should  be  as  905,  or  thereabouts, 
to  1000. 

16.  Spirit  of  Hartshorn — Liquor  Volatilit 
Cornu  Cervi,  P.  L. 

This  may  be  counterfeited  by  mixing 
the  aqua  ammonia  purs  with  the  distilled 
spirit  of  hartshorn,  in  order  to  increase 
the  pungency  of  its  smell,  and  to  enable 
it  to  bear  an  addition  of  water.  The 
fraud  is  detected  by  adding  alcohol  to  the 
sophisticated  spirit ;  for,  if  no  considera- 
ble coagulation  ensues,  the  adulteration  is 
proved.  It  may  also  be  discovered  by  the 
usual  effervescence  not  ensuing  with 
acids.  The  solution  should  have  the  spe- 
cific gravity  of  1500. 


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1 7-  Sulphate  of  Soda — Natron  Vitriolatuvi; 
P.  L.— Glauber's  Salt. 
This  salt  ought  not  to  contain  an  excess 
of  either  acid  or  alkali,  both  of  which  may 
be  detected  by  the  vegetable  infusions. 
Nor  should  it  be  mixed  With  earthy  or 
metallic  salts ;  the  former  of  which  are 
detected  by  carbonate,  and  the  latter  by 
prussiate  of  potash.  Muriate  of  soda  is 
discovered  by  adding  nitrate  of  barytes 
till  the  precipitate  ceases,  and  afterwards 
nitrate  of  silver,  or  more  simply  by  a  so- 
lution of  sulphate  of  silver.  Sulphate  of 
potash  is  discovered  by  its  more  sparing' 
solubility.  The  sulphate  of  soda,  howe- 
ver, being  itself  one  of  the  cheapest  salts, 
there  is  little  risk  of  its  being  intention- 
ally sophisticated. 

18,  Sulphate  of  Potash — Kali  I'itriolatum, 

P.  L. —  Vitriolated  Tartar. 
The  purity  of  this  salt  may  be  ascer- 
tained by  the  same  means  as  that  of  the 
former  one.  The  little  value  of  ibis  salt 
renders  it  pretty  secure  from  wilful  adul- 
teration. 

19.  Nitrate  of  Potash — Xitrum  Purifcu- 
tum,  P.  L. — Nitre  or  Salt  Petre. 

Nitrate  of  potash  is,  with  great  difficul- 
ty, freed  entirely  from  muriate  of  soda  ; 
and  a  small  portion  of  the  latter,  except 
for  nice  chemical  purposes,  is  an  admix- 
ture of  little  importance.  To  discover 
muriate  of  soda,  a  solution  of  nitrate  of 
silver  must  be  added  as  long  as  any  sedi- 
ment is  produced.  The  precipitate,  wash- 
ed and  dried,  must  be  weighed.  Every 
hundred  grains  will  denote  42$  of  muri- 
ate of  soda. 

Sulphate  of  potash  or  soda  may  be  dis- 
covered by  nitrate  or  muriate  of  barvtes. 

20.  Muriate  of  Soda.— Common  Silt. 

Common  salt  is  scarcely  ever  found 
free  from  salts  with  earthy  bases,  chiefly 
muriates  of  magnesia  and  lime,  which  are 
contained  in  the  brine,  and  adhere  to  the 
crystals.  The  earths  may  be  precipitat- 
ed by  carbonate  of  soda,  and  the  precipi- 
tated lime  and  magnesia  may  be  separat- 
ed from  each  other. 

21.  Muriate  of  Am  mom a  —Ammonia 
Muriata,  P.  L. —  Sal  Am  moniac. 
This  salt  ought  to  be  entirely  -volatiliz- 
ed, by  a  low  heat,  when  laid  on  a  heated 
iron.  It  sometimes  contains  sulphate  of 
ammonia,  however,  which  being  also  vo- 
latile, cannot  be  thus  detected.  To  as- 
certain the  presence  of  the  latter  salt,  acid 
the  muriate  or  nitrate  of  barvtes,  which 
will  indicate  the  sulphate  by  a  copious  and 
Insoluble  precipitate. 


22.  Acetate  of  Potash— Kali  Acetaium, 

P.  L. 

Genuine  acetate  of  potash  is  perfectly 
soluble  in  four  times  its  weight  of  alcohol, 
and  may  thus  be  separated  from  other 
salts  that  are  insoluble  in  alcohol.  The 
tartrite  of  potash  (soluble  tartar)  is  the 
adulteration  most  likely  to  be  employed. 
This  may  be  discovered  by  adding-  a  so- 
lution of  tartareous  acid,"  svhich,  if  the 
suspected  salt  be  present,  will  occasion  a 
copious  precipitate.  The  tartrite  is  also 
detected  by  its  forming  a  precipitate  with 
acetate  of  lead,  or  muriate  of  barytes,  so- 
luble in  acetic  or  muriatic  acid  :  and  sul- 
phates by  a  precipitate  with  the  same 
agents,  insoluble  in  acids. 

23.  JYiutral  Tartrite  of  Potash — KaliTar- 
tanzatum,  P  L. — Soluble  Tartar 

This  salt  should  afford  a  very  copious 
precipitate  on  adding  tartareous  acid. — 
The  only  salt  likely  to  be  mixed  with  rt 
is  sulphate  of  soda,  which  may  be  de- 
tected by  a  precipitate  with  muriated 
barytes,  insoluble  in  diluted  muriatic 
aciel. 

24.  Acidulous  T:rtrite  of  Potash — Tar- 
tarum  Pwifcatum,  P.  L. —  Cream  of 
Tartar. 

The  only  substance  with  which  this 
salt  is  likely  to  be  adulterated  is  sulphate 
of  potash.  To  determine  whether  this  be 
present,  pour  on  about  half  an  ounce  of 
the  powdered  crystals,  two  or  three  ounce 
measures  of  distilled  water;  shake  the 
mixture  frequently,  and  let  it  stand  one 
or  two  hours.  The  sulphate  of  potash, 
being  more  soluble  than  the  tartrite,  will 
be  taken  up  ;  and  may  be  known  by  the 
bitter  taste  of  the  solution,  and  by  a  pre- 
cipitate, on  adding  muriate  of  barytes, 
which  will  be  insoluble  in  muriatic  acid. 

25.  Compound  Tartrite  of  Soda  and  Pot- 
ash— Natron  Tartarizatum,   P.  L  

Rochellc  or  Seignette's  Salt. 

Sulphate  of  soda,  the  only  salt  with 

which  this  may  be  expected  to  be  adul- 
terated, is  discovered  by  adding  to  a  so- 
lution of  Rochelle  salt,  the  acetite  of  lead 
or  muriate  of  barytes.  The  former,  if  the 
sulphate  be  present,  affords  a  precipitate 
insoluble  in  acetous  acid,  and  the  latter 
one,  insoluble  in  muriatic  acid. 

26.  Sulphate  of  Magnesia — Magnesia  Vi- 

triolata,  P.  L. — Epsom  Salt. 
This  salt  is  very  likely  to  be  adulterat- 
ed with  sulphate  of  soda,  or  Glauber's 
salt,  which  may  be  made  to  resemble  the 
magnesian  salt  in  appearance,  by  stirring 
it  briskly  at  the  moment  it  is  about  tr 


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crystallize.  The  fraud  may  be  disco- 
vered very  readily,  if  the  salt  consists 
entirely  of  the  sulphate  of  soda,  because 
no  precipitation  will  ensue  on  adding 
carbonate  of  potash.  If  only  a  part  of 
the  sulphate  of  soda,  detection  is  not  so 
easy,  but  may  still  be  accomplished.  For, 
since  100  parts  of  pure  sulphate  of  mag- 
nesia, give  between  30  and  40  of  the  dry 
carbonate,  when  completely  decomposed 
by  carbonate  of  potash,  if  the  salt  under 
examination  afford  a  considerably  less 
proportion,  its  sophistication  may  be  fairly 
inferred  :  or,  to  discover  the  sulphate  of 
soda,  precipitate  all  the  magnesia,  by 
pure  ammonia,  with  the  aid  of  beat.  De- 
cant the  clear  liquor  from  the  precipitate, 
filter  it,  and,  alter  evaporation  to  dryness, 
apply  such  a  heat,  as  will  volatilize  the 
sulphate  of  ammonia,  when  that  of  soda 
will  remain  fixed. 

Muriate  of  manganese  or  of  lime,  may 
be  detected  by  the  salt  becoming  moist, 
when  exposed  to  the  air,  and  by  a  preci- 
pitation with  nitrated  silver,  after  nitrate 
of  barytes  has  separated  all  the  sulphuric 
acid  and  magnesia.  Lime  is  discoverable 
by  oxalic  acid. 

27.  Sulphate  of  Alumine — Alum. 
Perfectly  pure  alum,  should  contain 
neither  iron  or  copper.  The  formes  is 
manifested  by  adding,  to  a  solution  of 
alum,  prussiale  of  potash,  and  the  latter 
by  an  excess  of  pure  ammonia. 

23.  Borate  of  Soda — Borax. 
Borate  of  soda,  if  adulterated  at  all, 
will  probably  be  so  with  alum,  or  fused 
muriate  of  soda.  To  discover  these,  bo- 
rax must  be  dissolved  in  water,  and  its 
excess  of  alkali  be  saturated  with  nitric 
acid.  Nitrate  of  barytes,  added  to  this 
saturated  solution,  will  detect  the  sulphu- 
ric salt,  and  nitrate  of  silver  the  muriate 
of  soda. 

29.  Sulphate  of  Iron — Ferrum  Vitriolatum, 

P.  L. —  Green  Vitriol. 
If  this  salt  should  contain  copper,  which 
is  the  only  admixture  iikely  to  be  found 
in  it,  pure  ammonia,  added  till  a  precipi- 
tation ceases,  will  afford  a  blue  liquor. 
Any  copper  that  may  chance  to  be  pre- 
sent,  may  be  separated,  and  the  salt  pu- 
rified, by  immersing  in  a  solution  of  it,  a 
clear  polished  plate  of  iron. 

30.  Tartarized  Antimony  intimonium 

Tartarizatum,  P.  L. — Emetic  Tartar. 
A  solution  of  this  salt  should  afford, 

with  acetate  of  lead,  a  precipitate  perfect- 
ly soluble  in  dilute  nitric  acid.  A  few 
drops  of  the  sulphuret  of  ammonia,  also, 


should  immediately  precipitate  a  gold-co- 
loured  sulphuret  of  ammonia. 

3 1 .  Muriate  of  Mercury — Jlydrar gyrus  Mu- 
riatus,  P.  Ij — Corrosive  Sublimate. 
If  tthere  be  any  reason  to  suspect  ar- 
senic in  this  salt  the  fraud  may  be  disco- 
vered as  follows  :  Dissolve  a  small  quan- 
tity of  the  sublimate,  in  distilled  water  ; 
add  a  solution  of  carbonate  of  ammonia, 
till  the  precipitate  ceases,  and  filter  the 
solution.  If,  on  the  addition  of  a  few  drops 
of  ammoniated  copper,  (prepared  by  di- 
gesting a  little  verdegris  in  the  solution 
of  pure  ammonia,)  to  this  solution,  a  pre- 
cipitate of  a  yellowish  green  colour,  is 
produced,  the  sublimate  contains  arse- 
nic. 

32.  Sub-muriate  of  Mercury — Calomel, 
P.L. 

Calomel  should  be  completely  saturat- 
ed  with  mercury.  This  may  be  ascertain- 
ed by  boiling,  for  a  few  minutes,  one  part 
of  calomel  with  one-thirty-second  part  of 
muriate  of  ammonia,  (sal  ammoniac)  in 
ten  parts  of  distilled  water.  When  car- 
bonate of  potash  is  added  to  the  filtered 
solution,  no  precipitation  will  ensuse,  if 
the  calomel  be  pure.  This  preparation, 
when  rubbed  in  an  earthen  mortar  with 
pure  ammonia,  should  become  intensely 
black,  and  should  exhibit  nothing  of  an 
orange  hue. 

33.  Mercury ',  or  Quicksilver — Hydrargyrus 
P.  L. 

Scarcely  any  substance  is  so  liable  to 
adulteration  as  mercury,  owing  to  the  pro- 
perty which  it  possesses  of  dissolving 
completely  some  of  the  baser  metals.  This 
union  is  so  strong  that  they  even  rise  along 
with  the  quicksilver  when  distilled.  The 
impurity  of  mercury  is  generally  indica- 
ted by  its  dull  aspect ;  by  its  tarnishing 
and  becoming  covered  with  a  coat  of  ox- 
ide on  long"  exposure  to  the  air ;  by  its 
adhesion  to  the  surface  of  glass  ;  and, 
when  shaken  with  water  in  a  bottle,  by 
the  speedy  formation  of  a  black  powder. 
Lead  and  tin  are  frequent  impurities,  and 
the  mercury  becomes  capable  of  taking 
up  more  of  these  if  zinc  or  bismuth  be 
previously  added.  In  order  to  discover 
lead,  the  mercury  may  be  agitated  with  a 
little  water,  in  order  to  oxydize  that  me- 
tal. Pour  off  the  water,  and  digest  the 
mercury  with  a  little  acetous  acid.  This 
will  dissolve  the  oxide  of  lead,  which  will 
be  indicated  by  a  blackish  precipitate  with 
sulphuretted  water.  Or,  to  this  acetous 
solution,  add  a  little  sulphate  of  soda, 
which  will  precipitate  a  sulphate  of  lead, 
containing,  when  dry,  72  per  cent,  of  mc- 


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tal.  If  only  a  very  minute  quantity  of 
lead  be  present,  in  a  large  quantity  of 
mercury,  it  may  be  detected  by  solution 
in  nitric  acid  and  the  addition  of  sulphu- 
retted water.  A  dark  brown  precipitate 
will  ensue,  and  will  subside  if  allowed  to 
stand  a  few  days.  One  part  of  lead  may 
thus  be  separated  from  15-63  parts  of 
mercury.  (See  Mr.  Accum's  valuable  pa- 
pers on  the  detection  of  adulterations,  in 
^Nicholson's  Journal,  4to.)  Bismuth  is  de- 
tected by  pouring  a  nitric  solution,  pre- 
pared without  heat,  into  distilled  water ;  a 
white  precipitate  will  appear  if  this  metal 
be  present.  Tin  is  manifested,  in  like 
manner,  by  a  weak  solution  of  nitro-mu- 
riate  of  gold,  which  throws  down  a  purple 
sediment,  and  zinc  by  exposing  the  metal 
to  heat. 

34.  Red  Oxide  of  Mercury — JJydrargyrus 

Calcinatus,  P.  L. 
This  substance  is  rarely  found  adulte- 
rated, as  it  would  be  difficult  to  find  a 
substance  well  suited  to  this  purpose.  If 
well  prepared,  it  may  be  totally  volati- 
lized by  heat. 

35.  Red  Oxide  of  Mercury  by  Nitric  Mid 
—  JJydrargyrus  JVitratus  Ruber,  1>.  £  — 
Red  Precipitate 

This  is  very  liable  to  adulteration  with 
minium,  or  red  lead.  The  fraud  may  be 
discovered  by  digesting  it  in  acetic  acid, 
and  adding  to  the  solution  sulphuretted 
water,  or  sulphuret  of  ammonia,  which 
produce,  with  the  compounds  of  lead,  a 
dirty  dark  coloured  precipitate.  It  should 
also  be  totally  volatilizabie  by  heat. 

36.  White  Oxide  of  Mercury —  Calx  Hy- 
drargyri  Alba,  P.  L. —  White  Precipi- 
tate. 

"White  lead  is  the  most  probable  adul- 
teration of  this  substance,  and  chalk  may 
also  be  occasionally  mixed  with  it.  The 
oxide  of  lead  may  be  discovered  as  in  the 
last  article ;  and  chalk,  by  adding  to  the 
dilute  solution  a  little  oxalic  acid. 

37.  Red  Sulphuretted  Oxide  of  Mercury — 
JJydrargyrus  Sulphur atus  Ruber,  I*.  L. — 
Factitious  Cinnabar. 
This  substance  is  frequently  adulte- 
rated with  red  lead,  which  may  be  detect- 
ed by  the  foregoing  rides.  Chalk  and  dra- 
gon's blood  are  also  sometimes  mixed 
with  it    The  chalk  is  discovered  by  an 
effervescence  on  adding  acetic  acid,  and 
by  pouring  oxalic  acid  into  the  acetous 
solution.  "Dragon's  blood  will  be  left  un- 
volatilized  when  the  sulphuret  is  exposed 
to  heat,  and  may  be  detected  by  its  giving 


a  colour  to  alcohol,  when  the  cinnabar  is 
digested  with  it. 

38.  Black  Sulphuretted  Oxide  of  Mercury 
— JJydrargyrus  cum  Sulphure,  P.  L. — 
Ethiops  Mineral. 

The  mercury  and  sulphur,  in  this  pre- 
paration, should  be  so  intimately  com- 
bined, that  no  globules  of  the  metals  can 
be  discovered  by  a  magnifier ;  and  that, 
when  rubbed  on  gold,  no  white  stain  may 
be  communicated.  The  admixture  of 
ivory  black  may  be  detected  by  its  not 
being  wholly  volatilized  by  heat;  or,  by 
boiling  with  alkali  to  extract  the  sulphur, 
and  afterwards  exposing  the  residuum  to 
heat,  which  ought  entirely  to  evaporate. 

39.  Yellow  Oxide  or  Sub- Sulphate  of  Mer- 
cury— JJydrargyrus  Vitriolatus,  P.  L.— 
Turbith  Mineral. 

This  preparation  should  be  wholly  eva- 
porable ;  and,  when  digested  with  distill- 
ed water,  the  water  ought  not  to  take  up 
any  sulphuric  acid,  which  will  be  disco- 
vered by  muriate  of  barytes. 

40.  Fused  Nitrate  of  Silver — Argentum  JYi- 

tratum,  P.  L. —  Lunar  Caustic. 
The  most  probable  admixture  with  this 
substance  is  nitrate  of  copper,  derived 
from  the  employment  of  an  impure  silver. 
In  moderate  proportion  this  is  of  little  im- 
portance. It  may  be  ascertained  by  solu- 
tion in  water,  and  adding  an  excess  of 
pure  ammonia,  which  will  detect  copper 
by  a  deep  blue  colour. 

41.  White  Oxide  of  Zinc — Zincum  Calci- 

natum,  P.  Jj. — Flowers  of  Zinc. 
Oxide  of  zinc  may  be  adulterated  with 
chalk,  which  is  discoverable  by  an  effer 
vescence  with  acetous  acid,  and  by  the 
precipitation  of  this  solution  with  oxalic 
acid.  Lead  is  detected  by  adding,  to  the 
acetous  solution,  sulphuretted  water,  or 
sulphuret  of  ammonia.  Arsenic,  to  which 
the  activity  of  this  medicine  has  been 
sometimes  ascribed,  is  detected,  also,  by 
sulphuretted  water,  added  to  tne  acetous 
solution ;  but  in  this  case  the  precipitate 
has  a  yellow  colour,  and,  when  laid  on  red 
hot  charcoal,  gives  first  a  smell  of  sul- 
phur, and  afterwards  of  arsenic. 

42.  White  Oxide  of  J^ead—Cerussa,  P.  Z. 

White  J.ead. 
This  is  frequently  sophisticated  with 
chalk  ;  the  presence  of  which  may  be  de- 
tected by  cold  acetous  acid,  and  by  add- 
ing, to  this  solution,  oxalic  acid.  Carbo- 
nate of  barytes  is  detected  by  sulphate  of 
soda  added  to  the  same  solution,  very 


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largely  dilated  with  distilled  water ;  and 
sulphate  of  barytes,  or  sulphate  of  lead, 
by  the  insolubility  of  the  ceruse  in  boiling- 
distilled  vinegar. 

43.  Acetate  of  Lead—Cerusa  Acetata,  P 

L. — Sugar  of  Lead. 

If  the  acetate  of  lead  should  be  adulte- 
rated with  acetate  of  lime  or  of  barytes, 
the  former  may  be  detected  by  adding,  to 
a  dilute  solution,  the  oxalic  acid ;  and  the 
latter  by  sulphuric  acid,  or  solution  of 
sulphate  of  soda,  added  to  a  solution  very 
largely  diluted  with  water.  Acetate  of 
lead  ought  to  dissolve  entirely  in  water, 
and  any  thing  that  resists  solution  may  be 
regarded  as  an  impurity. 

44.  Green  Oxide  or  Sub-acetate  of  Copper. 

Verdigris. 

This  substance  is  scarcely  ever  found 
pure,  being  mixed  with  pieces  of  copper, 
grape-stalks,  and  other  impurities.  The 
amount  of  this  admixture  of  insoluble  sub- 
stances may  be  ascertained  by  boiling  a 
portion  of  verdigris  with  12  or  14  times 
its  weight  of  distilled  vinegar,  allowing 
the  undissolved  part  to  settle,  and  ascer- 
taining its  amount.  Sulphate  of  copper 
may  be  detected  by  boiling  the  verdigris 
with  water,  and  evaporating  the  solution. 
Crystals  of  acetite  of  copper  will  first  se- 
parate, and,  when  the  solution  has  been 
farther  concentrated,  the  sulphate  of  cop- 
per will  crystallize.  Or,  it  may  be  disco- 
vered by  adding  to  the  watery  solution 
muriate  of  barytes,  which  will  throw 
down  a  very  abundant  precipitate.  Tar- 
trite  of  copper,  another  adulteration  some- 
times met  with,  is  discovered  by  dissolv- 
ing a  little  of  the  verdigris  in  acetous  acid, 
and  adding  acetite  or  muriate  of  barytes, 
which  will  afford,  with  the  tartarous  acid, 
a  precipitate  soluble  in  muriatic  acid. 

45.  Crystallized  Acetate  of  Copper— Dis- 

tilled or  Crystalliztd  Verdigris. 

This  is  prepared  by  dissolving  the  com- 
mon verdigris  in  distilled  vinegar,  and 
crystallizing  the  solution.  These  crys- 
tals should  dissolve  entirely  in  six  times 
their  weight  of  boiling  water,  and  the  so- 
lution should  give  no  precipitation  with 
solutions  of  barytes  ;  for,  if  these  solu- 
tions throw  down  a  precipitate,  sulphate 
of  copper  is  indicated.  This  impurity, 
which  I  have  frequently  met  with,  may 
be  discovered  by  evaporating  the  solution 
•very  low,  and  separating  the  crystals  of 
acetate  of  copper.  Farther  evaporation 
and  cooling  will  crystallize  the  sulphate, 
if  any  be  present. 

VOL.  II. 


46.  Carbonate  of  Magnesia— Magnesia  Al- 
ba, P.  L. 

Carbonate  of  magnesia  is  most  liable  to 
adulteration  with  chalk;  and,  as  lime 
forms  with  sulphuric  acid  a  very  insolu- 
ble salt,  and  magnesia  one  very  readily 
dissolved,  this  acid  may  be  emploved  in 
detecting  the  fraud.  To  a  suspected  por- 
tion of  magnesia  add  a  little  sulphuric 
acid,  diluted  with  8  or  10  times  its  weight 
of  water.  If  the  magnesia  should  entire- 
ly be  taken  up,  and  the  solution  should  re- 
main transparent,  it  may  be  pronounced 
pure,  but  not  otherwise.  Another  mode 
of  discovering  the  deception  is  as  follows  : 
Saturate  a  portion  of  the  suspected  mag- 
nesia with  muriatic  acid,  and  add  a  solu- 
tion of  carbonate  of  ammonia.  If  any 
lime  be  present,  it  will  form  an  insoluble 
precipitate,  but  the  magnesia  will  remain 
in  solution. 

47'  Pure  Magricsia — Magnesia  Usta,  P. 
L.— Calcined  Magnesia. 
Calcined  magnesia  may  be  assayed  by 
the  same  tests  as  the  carbonate.  It  ought 
not  to  effervesce  at  all  with  dilute  sulphu- 
ric acid ;  and,  if  the  earth  and  acid  be 
put  together  into  one  scale  of  a  balance, 
no  diminution  of  weight  should  ensue  on 
mixing  them  together,  It  should  be  per- 
fectly free  from  taste,  and,  when  digested 
with  distilled  water,  the  filtered  liquor 
should  manifest  no  property  of  lime-water. 
Calcined  magnesia,  however,  is  very  sel- 
dom so  pure  as  to  be  tot  ally  dissolved  by 
diluted  sulphuric  acid ;  for  a  small  inso- 
luble residue  generally  remains,  consist- 
ing chiefly  of  siliceous  earth,  derived  from 
the  alkali.  The  solution  in  sulphuric  acid, 
when  largely  diluted,  ought  not  to  afford 
any  precipitation  with  oxalate  of  ammonia. 

48.  Spirit  of'  Wine,  Alcohol,  and  AEthers. 

The  only  decisive  mode  of  ascertaining 
the  purity  of  spirit  of  wine  and  of  aethers, 
is  by  determining  their  specific  gravity. 
Highly  rectified  alcohol  should  have  the 
specific  gravity  of  820  to  1000.  Common 
spirit  of  wine  837.  Sulphuric  aether  739- 
The  spiritus  setherius  vitriolicus,  P.  L.,  or 
sweet  spirit  of  vitriol,  about  753,  and  ni- 
tric aether,  the  spiritus  setherius  nitrosus, 
or  sweet  spirit  of  nitre,  908.  The  others 
ought  not  to  redden  the  colour  of  litmus, 
nor  ought  those  formed  from  sulphuric 
acid  to  give  any  precipitation  with  solu 
tions  of  barytes. 

49.  Essential,  or  Volatile  Oil. 
As  essential  oils  constitute  only  a  ver\ 
small  proportion  of  the  vegetables  from 
which  they  are  obtained,  and  bear  gene- 
rally a  very  high  price,  there  is  a  consi- 
3  o 


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devable  temptation  to  adulterate  them. 

They  are  found  sophisticated,  either  with 
cheaper  volatile  oils,  with  fixed  oils,  or 
w'uh  the  spirit  of  wine  The  fixed  oils  are 
discovered  by  distillation  with  a  very 
gentle-  heat,  which  elevates  the  essential 
oik,  and  Leaves  the  fixed  ones.  These  last 
may,  aNo,  be  detected  by  moistening  a 
little  wi;iting  paper  with  the  suspected 
oil,  and  holding  it  before  the  fire.  If  the 
oil  be  entirely  essential,  no  stain  will  re- 
main on  the  paper.  Alcohol,  also,  detects 
the  fixed  oils,  because  it  only  dissolves 
the  essential  ones,  and  the  mixture  be- 
comes milky.  The  presence  of  cheaper 
essen  lal  ons  is  discovered  by  the  smell. 
Alcohol,  a  cheaper  liquid  than  some  of 
the  most  costly  essential  oils,  is  discover- 
ed by  adding  water,  whieh,  if  alcohol  be 
present,  occasions  a  milkiness. 

TESTS,  OR  CUPELS,  in  assaying.  See 
Assaying. 

TESTS,  Manufacture  of. 

The  preparation  of  re-agents  may  be 
noticed  in  a  general  manner.  Although 
the  formation  of  a  number  of  articles, 
which  are  used  for  the  purpose  of  chemi- 
cal investigation,  has  been  noticed  in  dif- 
ferent parts  of  our  work,  yet  we  shall  enu- 
merate them,  and  treat  of  such  in  this 
place,  whose  preparation  has  not  been 
heretofore  mentioned. 

1.  Infusion  of  Litmus. 

This  preparation  is  made  as  before  no-' 
ticed,  namely,  by  steeping  litmus,  first 
bruised  in  a  mortar,  and  tied  up  in  a  thin 
rag,  in  distilled  water. 

2.  Syrup  of  Violets. 

Is  prepared  by  making  a  decoction  of 
the  violets,  adding  white  sugar,  and  boil- 
ing it  down  to  a  syrup.  As  sold  in  the 
shops,  it  is  mostly  impure  :  directions  for 
discovering  its  sophistication,  may  be 
found  in  the  article,  on  the  use  of  re 
agents. 

3.  Litmus  Paper.    See  Tests. 

4.  Litmus  Paper,  or  the  infusion,  reddened 
by  an  acid. 

This  operation  is  performed,  on  the  pa- 
per, by  immersing  it  in  a  weak  acid,  the 
phosphoric  diluted,  is  generally  preferred; 
or  by  adding  to  the  infusion,  a  portion  of 
acid  until  the  colour  is  sufficiently  chang- 
ed. 

A  drop  of  sulphuric  acid  put  into  a  half 
pint  of  water,  or  common  vinegar  alone, 
may  be  employed. 


5.  Tincture  of  Tut  meric,  of  Brazil-wood, 

or  of  Rnubarb. 
May  be  mad;  by  digesting  the  mate- 
rial, previously  bruised,  in  a  mixture  of 
equal  parts  of  alcohol  and  water  ;  after- 
wards filtering  the  fluid. 

6.  Turmttic,  Hazel-woody  or  Rhubarb 
Paper 

Is  prepared  by  staining  unsized  pa- 
per with  the  tincture,  or  infusion  of  these 
substances. 

7.  Gallic  Acid.    See  Gallic  Acid. 

8.  Tincture  of  Galls. 
Is  prefered  to  the  gallic  acid  as  a  test : 
it  is  prepared  by  digesting  the  bruised 
galls  in  alcohol,  or  in  common  spirit,  and 
afterwards  filtering  the  liquor. 

9.  Sulphuric  Acid.  See  Sulphuric 
Acid. 

As  the  acid  should  be  pure  when  used 
as  a  test,  drections  are  given  for  that 
purpose,  in  the  article  on  its  manufacture; 
and  to  determine  its  purity,  if  purchased 
out  of  the  stores,  see  the  uses  of  tests,  un- 
der the  head  of  test. 

10.  Mtric  Acid.    See  Nitric  Acid. 

11.  Otcalic  Acid.  It  may  be  obtained, 
readily  and  economically  from  sugar  in 
the  following  way  :  to  six  ounces  of  nitric 
acid  in  a  stoppered  retort,  to  which  a 
large  receiver  is  luted,  add  by  degrees  one 
ounce  of  lump  sugar,  coarsely  powdered. 
A  gentle  heat  may  be  applied  during  the 
solution,  and  nitric  oxide  will  be  evolved 
in  abundance.  When  the  whole  of  the 
sugar  is  dissolved,  distil  off  a  part  of  the 
acid,  all  what  remains  in  the  retort  has  a 
sirupy  consistence,  and  this  will  form  re- 
gular crystals,  amounting  to  58  parts  from 
1U0  of  sugar.  These  crystals  must  be 
dissolved  in  water,  re-crystallized,  and 
dried  on  blotting  paper. 

12.  Oxalate  of  Potash. 
May  be  formed  by  saturating  oxalic 
acid  dissolved  in  water  with  pure  potash  ; 
or  by  saturating  the  excess  of  acid  in  salt 
of  sorrel  with  potash. 

13.  Super -Oxalate  of  Potash. 
Is  the  salt  of  sorrel,  which  may  be  ob- 
tained in  a  crystallized  state,  by  evapo- 
rating the  juice  of  that  plant ;  or  by  super- 
saturating  potash  with  oxalic  acid. 

14.  Oxalate  of  Ammonia, 
Is  made  by  saturating  oxalic  acid,  with 


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ammonia  or  pure  volatile  alkali.  For  this 
purpose,  the  oxalic  acid  may  be  saturated 
with  the  carbonate  of  ammonia,  which  is 
known  when  the  effervescence  ceases. 

15.  Oxalate  of  Soda, 
May  be  made  by  saturating"  the  acid 
with  soda,  or  its  carbonate  in  a  similar 
manner. 

16  Fluate  of  Ammonia, 

May  be  formed  by  adding  carbonate  of 
ammonia, to  diluted  fluoric  acid  in  a  leaden 
vessel,  observing-  that  there  be  a  small 
excess  of  acid.  The  fluoric  acid  is  form- 
ed, by  distilling-  two  parts  of  fiuor  spar, 
and  one  of  oil  of  vitriol ;  the  gas  comes 
over  and  may  be  condensed. 

17.  Pure  Ammonia  (aqua  ammonice  puree.) 

Is  a  solution  of  ammoniacal  gas  in  water, 
made  by  receiving  the  gas  disengaged 
from  two  parts  of  sal  ammoniac,  and  one 
of  quicksilver,  previously  placed  in  a  re- 
tort and  heated,  in  a  vessel  containing 
distilled  water.  It  is  the  caustic  spirit  of 
sal  ammoniac  of  the  shops. 

18.  Pure  Potash.  See  Potash 
This  alkali  is  obtained  in  a  state  of  pu- 
rity, by  depriving  the  common  potash  of 
carbonic  acid  by  means  of  lime,  and  then 
evaporating  the  alkaline  solution  to  dry- 
ness, and  dissolving  it  in  alcohol  The 
solution  in  alcohol  is  then  evaporated  to 
dryness.  If  caustic  potash  be  dissolved 
in  alcohol,  and  treated  in  the  same  man- 
ner, the  same  preparation  will  be  formed. 
For  more  minute  directions,  See  Pot- 
ash. 

19.  Pure  Soda, 
May  be  formed  in  the  same  manner. 

20.  Carbonate  of  Ammonia. 
This  salt  may  be  made  by  saturating< 
the  liquid  ammonia  with  carbonic  acid : 
it  is  the  sal.  volat.  ammonia  of  the  shops. 
This  last,  however,  contains  a  variable 
quantity  of  carbonic  acid. 

21.  Carbonate  of  Potash. 
This  salt  may  be  prepared  by  saturat- 
ing the  pure  alkali  with  carbonic  acid,  in 
a  Nooth's  machine  :  the  sub  carbonate,  is 
the  salt  of  tartar  of  the  shops. 

22.  Carbonate  of  Soda, 

May  be  prepared  in  the  same  manner. 
The  carbonate  of  the  shops,  is  the  prepar. 
ed  Natron  of  the  dispensatories,  and  con 
<ains  a  variable  quantity  of  carbonic  acid. 


23.  Lime  Water. 
This  is  made  by  putting  pure  water  on 
quicklime,  or  fresh  burnt  lime  ;  and  after 
standing  some  time  decanting  the  pure 
solution,  bee  Lime. 

24.  Barytic  Water, 

Is  made  by  dissolving  pure  barytes  in 
water.  For  the  preparation  of  pure  ba- 
rytes.   See  Earths. 

25.  Strontian  Water. 

Is  made  in  the  same  manner.  See 
Strontian, article  Earths. 

26.  Sulphate  of  Iron.    See  Iron. 


27.  Nitrate  of  Silver.' 

28.  Sulphate  of  Silver.  j 

29.  Acetate  of  Silver.  ' 


See  Silver, 


30.  Acetate  of  Lead.    See  Lead. 

31.  Mtrate  <f  Lead, 
Is  made  by  dissolving  lead,  to  satura- 
tion, in  nitric  acid.    See  Lead. 

32  Nitrate  of  Mercury, 
Prepared  with  or  without  heat,  is  made 
by  dissolving  mercury  to  saturation  in 
nitric  acid,  with  or  without  the  assistance 
of  heat.    See  Mercury. 

33.  Prussiate  of  Potash. 
For  the  mode  of  making  an  impure 
prussiate  for  the  use  of  the  colour  maker, 
see  Colour  Making.  But  for  the  pur- 
poses of  the  chemist,  it  is  made  generally 
in  the  following  manner :  Prussian  blue 
is  pulverized,  and  a  solution  of  common 
potash  is  added,  and  digested  on  it ;  this 
is  then  decanted,  and  another  portion  add- 
ed. This  operation  is  to  be  continued 
until  the  colour  ceases  to  be  discharged. 
Filter  the  liquor,  wash  the  sediment  with 
water,  till  it  ceases  to  extract  any  thing, 
mix  the  washings  together,  and  pour  the 
mixture  into  an  earthen  dish,  in  a  sand- 
heat.  When  the  solution  has  become  hot, 
add  a  little  dilute  sulphuric  acid,  and 
continue  the  heat  about  an  hour.  A  co- 
pious precipitate  of  Prussian  blue  will  be 
formed,  which  must  be  separated  by  fil- 
tration, and  assay  a  small  quantity  of  the 
filtered  liquor  in  a  wine  glass,  with  a  little 
dilute  sulphuric  acid.  If  an  abundant 
production  of  Prussian  blue  still  takes 
place,  the  whole  liquor  must  be  again  ex- 
posed to  heat,  with  a  little  dilute  sulphu- 
ric acid,  and  this  must  be  repeated  as  of- 
ten as  necessary.  Into  the  liquor  thus 
far  purified,  pour  a  solution  of  sulphat  of 
copper,  into  four  or  six  times  its  weight  of 


TES 


TES 


warm  water,  as  long  as  a  reddish  brown 
precipitate  continues  to  appear.  Wash 
this  precipitate,which  is  a  prussiate  of  cop- 
per, with  repeated  affusions  of  warm  wa- 
ter ;  and  when  these  come  off  colourless 
lay  the  precipitate  on  a  linen  filter  to  drain, 
after  which  it  may  be  dried  on  a  chalk 
stone.  When  the  precipitate  is  dry,  pow- 
,der  it,  and  add  it  by  degrees  to  a  solution 
of  pure  potash,  which  will  take  the  prus- 
sic  acid  from  the  oxide  of  copper.  This 
prussiate  of  potash,  however,  will  be  con- 
taminated by  some  portion  of  sulphat  of 
potash,  from  part  of  which  it  may  be  freed 
by  gentle  evaporation,  as  the  sulphat  crys- 
tallizes first.  To  the  remaining  liquor 
add  a  solution  of  barytes  in  warm  water, 
as  long  as  a  white  precipitate  ensues,  ob- 
serving not  to  add  more  after  its  cessation. 
The  solution  of  prussiate  of  potash,  will 
now  be  freed  in  agreat  measure  from  iron, 
and  entirely  from  sulphats,  and  by  gentle 
evaporation,  will  form  on  cooling  beauti- 
ful crystals.  These  dissolved  in  cold  wa- 
ter, afford  the  best  prussiate  of  potash,that 
can  be  prepared.  If  pure  barytes  be  not  at 
hand,  acetate  of  barytes  may  be  used  in- 
stead ;  as  the  acetate  of  potash  formed, 
not  being  crystallizable,  will  remain  in  the 
mother-water. 

The  common  prussiate  of  potash,  or 
properly  triple  prussiate  of  potash,  may 
be  formed,  by  digesting  a  solution  of  the 
carbonate  of  potash  of  the  shops,  in  Prus- 
sian blue. 

34.  Prussiate  of  Soda. 

May  be  prepared  in  a  similar  manner, 
to  the  foregoing. 

35.  Prussiate  of  Lime. 

This  preparation  is  made  by  digesting 
lime  water  on  prussian  blue.  Made  in 
this  way,  it  is  a  triple  prussiate. 

36.  Succinic  Acid, 
Is  formed  by  the  sublimation  of  amber. 
It  is  purified  by  solution  and  crystalliza- 
tion. 

37.  Succinate  of  Ammonia, 
Is  formed  by  saturating  the  succinic 
acid  with  the  carbonate  of  ammonia,  or 
the  pure  ammonia. 

38.  Succinate  of  Soda, 
Is  formed  in  the  same  manner. 

39.  Phosphate  of  Soda. 

This  phosphat  is  now  commonly  pre- 
pared by  adding  to  the  acidulous  phos- 
phate of  lime  as  much  carbonate  of  soda 
in  solution  as  will  fully  saturate  the  acid. 
The  carbonate  of  lime,  which  precipi- 
tates, being  separated  by  filtration,  the 


liquid  is  duly  evaporated  so  as  to  crystal- 
lize the  phosphate  of  soda ;  but  if  there 
be  not  a  slight  excess  of  alkali,  the  crys- 
tals will  not  be  large  and  regular.  Mr 
Funcke,  of  Linz,  recommends,  as  a  more 
economical  and  expeditious  mode,  to  sa- 
turate the  excess  of  lime  in  calcined 
bones  by  dilute  sulphuric  acid;  and  dis- 
solve the  phosphate  of  lime  that  remains 
in  nitric  acid.  To  this  solution  he  adds 
an  equal  quantity  of  sulphate  of  sodas 
and  recovers  the  nitric  acid  by  distilla 
tion.  He  then  separates  the  phosphate 
of  soda  from  the  sulphate  of  lime,  by  elu- 
triation  and  crystallization  as  usual.  The 
crystals  are  rhomboidal  prisms  of  differ- 
ent shapes  ;  efflorescent ;  soluble  in  3 
parts  of  cold  and  H  of  hot  water.  They 
are  capable  of  being  fused  into  an  opake 
white  glass,  which  may  be  again  dissolv  - 
ed  and  crystalliied.  It  may  be  converted 
into  an  acidulous  phosphate  by  an  addi- 
tion  of  acid,  or  by  either  of  the  strong 
acids,  which  partially,  but  not  wholly,  de 
compose  it.  As  its  taste  is  simply  saline, 
without  any  thing  disagreeable,  it  is  much 
used  as  a  purgative,  chiefly  in  broth,  in 
which  it  is  not  distinguishable  from  com- 
mon salt.  For  this  elegant  addition  to 
our  pharmaceutical  preparations  we  are 
indebted  to  Dr.  Pearson.  In  assays  with 
the  blowpipe  it  is  of  great  utility ;  and  it 
has  been  used  instead  of  borax  for  sol- 
dering. 

40.  Muriate  of  Lime, 

Is  made  by  saturating  the  pure  muria- 
tic acid  with  lime :  the  carbonate  of  lime 
is  generally  added  until  the  effervescence 
ceases.  The  solution  is  afterwards  fil- 
tered. 

41.  Alcoholized  Soap, 

Is  formed  by  dissolving  white  soap  in 
alcohol,  and  filtering  tl>e  solution.  Thiii 
preparation  is  generally  called  the  solu 
tion  of  soap  in  alcohol. 

42-  Alcohol.    See  Alcohol. 

43.  Sulphuret,  and  Hydrosulphuret  of  Am* 
mania. 

Ammonia  may  be  combined  with  sul- 
phur by  mixing  together  two  parts  of  mu- 
riate of  ammonia,  two  of  lime,  and  one  of 
sulphur,  and  distilling  in  the  pneumatic 
apparatus,  with  a  small  quantity  of  water 
in  the  receiver.  A  yellow  liquor  is  ob- 
tained, containing  sulphuret  of  ammonia, 
formerly  known  by  the  name  of  Boyle's 
fuming  liquor.  If  sulphuretted  hydro- 
gen gas  be  passed  through  liquid  ammo- 
nia, a  compound  of  a  green  colour  will 
be  formed,  which  is  hydrosulphuret  of 
ammonia. 


TES 


TES 


44.  Water,  impregnated  with  sulphuretted 
Hydrogen, 

May  be  formed  on  letting  them  come 
in  contact,  by  passing  a  stream  of  the  gas 
through  water- 

45.  Uydrosufphuret  of  Potash  ">  Tnese 

46.  hydr osulphuret  of  Soda.  3 
preparations  may  be  made  by  saturating 
their  respective  alkalies  with  sulphuret- 
ted hydrogen  gas,  by  passing  the  gas 
through  the  alkaline  solution;  or  by 
melting  the  alkalies  with  sulphur,  and 
dissolving  the  compounds  in  water. 

47.  Nitro  Muriatic  Mid,  or  Aqua  Regia, 

Is  usually  made  by  mixing  two  parts  of 
nitric  acid  and  one  part  of  muriatic  acid. 

48.  Oxygenized  Muriatic  Acid 
For  the  preparation  of  this  acid,  see 
Bleaching,  and  Appendix  to  vol.  1. 

49.  Phosphoric  Acid. 

Although  this  acid  is  obtained  from 
bones  by  calcination,  and  the  addition  of 
sulphuric  acid,  yet,  by  that  mode,  it  is  al- 
ways impure ;  we  have  therefore  added 
the  following  more  approved  process  for 
obtaining  it  in  a  state  of  purity. 

Phosphorus  may  be  converted  into  this 
acid  by  treating  it  with  nitric.  In  this  ope- 
ration, a  tubulated  retort  with  a  ground 
stopper,  must  be  half  filled  with  nitric 
acid,  and  a  gentle  heat  applied.  A  small 
piece  of  phosphorus  being  then  introduc- 
ed through  tiie  tube,  will  be  dissolved 
with  effervescence,  produced  by  the  es- 
cape of  a  large  quantity  of  nitric  oxide. 
'The  addition  of  phosphorus  must  be  con- 
tinued until  the  last  piece  remains  undis- 
solved. The  fire  being  then  raised  to 
drive  over  the  remainder  of  the  nitric 
acid,  the  phosphoric  acid  will  be  found  in 
the  retort,  partly  in  the  concrete  and  par  t- 
ly in  the  liquid  form. 

We  have  made  this  acid  by  the  acidifi- 
cation of  phosphorus,  in  a  white  china 
bowl. 

50.  Acetous  Acid.  See  Acetous  Acid. 

51.  Tartarous  Acid.    See  Tartar. 

52.  Boracic  Acid.    See  Borax. 

53.  Muriate  of  Tin.    See  T 1  n. 

54.  Muriate  of  Barytes,  ~) 

55.  Nitrate  of  Barytes,    C  Are  made 

56.  Acetate  of  Barytes,  3 

by  dissolving  barytes,  either  the  pure 
earth,  or  its  carbonate,  in  the  respective 
acids.  For  the  preparation  of  pure  bary- 
tes, see  Earths,  article  Barytes. 

57.  Nitrate  of  Potash,   See  Nitre. 


58.  Sulphuret  of  JJme, 
Which  is  made  by  melting  two  parts  of 
sulphur  and  one  of  lime  together,  is  used 
not  as  a  reagent,  but  as  an  article,  from 
which  with  cream  of  tartar,  is  disengag- 
ed sulphuretted  hydrogen  gas  for  the 
purpose  of  detecting  the  presence  of  lead 
in  mines.  See  Hah  Neman's  Wine 
Test. 

59.  Muriated  Mercury,  or  Corrosive 
Sublimate.    See  Mercury. 

60  Ammoniated  Copper, 
May  be  made  by  dissolving  the  oxide  of 
copper  in  ammonia  :  if  the  dry  powder, 
which  remains  after  evaporation,  be  dis- 
solved in  water,  one  of  the  tests  for  the 
discovery  of  arsenic  will  be  formed.  See 
Poisons. 

61.  Nitro  Muriate  of  Platina. 
Is  prepared  by  dissolving  platina  in  ni- 
tro muriatic  acid,  which  is  a  mixed  acid 
prepared  as  directed  in  this  article.  This 
test  is  used  to  discriminate  between  pot- 
ash and  the  other  alkalies ;  it  will  produce 
a  precipitate  with  a  very  weak  solution  of 
any  salt  with  potash. 

62  Metallic  Cylinders. 
Several  of  the  metals,  as  has  been  ob- 
served, are  made  use  of  in  experiments  , 
for  the  convenience  of  use,  they  are  ge- 
nerally cast  or  made  into  the  cylindrical 
form.  Copper,  tin,  zinc,  and  iron,  are 
each  of  them  employed ;  and  occasionally 
silver,  mercury,  &c.  The  general  princi- 
ple on  which  they  act  may  be  noticed  ;  to 
wit.  Iron  precipitates  copper  from  its  so- 
lution ;  copper,  that  of  mercury  and  sil- 
ver ;  and  zinc,  that  of  tin  in  the  same  man- 
ner. Sometimes,  however,  metals  are  us- 
ed for  a  different  purpose. 

63.  Tincture  and  Infusion  of  red  Cabbage. 

The  latter  is  made  by  infusing  the  red 
leaves  of  this  plant  in  a  warm  water  of 
about  120  degrees  for  a  few  hours,  and 
the  former  by  digesting  the  leaves  in  dilut- 
ed alcohol.  To  preserve  the  cabbage  for  a 
length  of  time,  Mr.  Watt  advises,  to  mince 
the  leaves,  spread  them  on  paper,  and  dry 
them  with  a  gentle  heat,  and  put  them  in 
closely  stopped  bottles.  When  to  be  us- 
ed, digest  some  of  the  leaves  in  very  di- 
lute sulphuric  acid,  which  will  give  a  red 
colour;  bring  this  toexaci  neutralization 
with  chalk,  so  that  the  colour  is  a  pure 
blue  inclining  to  green  or  purple,  and  then 
pour  off  the  clear  liquor  and  employ  it. 
By  adding  a  little  alcohol,  it  will  keep  for 
some  time. 

This  test  is  changed  to  red  by  acids, 
and  is  therefore  a  test  fof  uncombined 


THE 


THE 


acid,  and  to  green  by  alkalies,  and  is  there- 
fore a  test  for  alkali. 

64  CWuriated  Alumine, 
Is  made  by  saturating  muriatic  acid 
with  alumine,  and  is  used  as  a  test  to  de- 
tect carbonate  of  magne  ia  in  waters.  By 
adding  this  test  to  a  boiled  water,  a  solu- 
tion, a  precipitate  of  carbonate  of  magne- 
sia, will  be  found,  if  carbonate  of  magne- 
sia is  present,  but  in  no  other  case,  unless 
there  be  an  excess  of  alkali,  which  may 
easily  be  neutralized.  , 

65.  .Muriate  of  Gold, 
Is  formed  by  dissolving  gold  in  nitro 
muriatic  acid,  prepared  in  the  manner  be- 
fore noticed.  It  is  used  for  several  pur- 
poses. With  a  solution  of  tin,  it  forms  a 
purple  precipitate  j  see  Gold  and  Tiw. 

66.  .Muriate  cf  Strontian, 

67.  Nitrate  of  Strontian,   \.  Are  form- 

68.  Acetate  of  Strontian,  j 

ed  by  dissolving  the  earth  of  strontian  in 
the  muriatic,  nitric,  and  acetic  acid.  The 
solution,  when  effected,  may  be  concen- 
trated by  evaporation. 

69.  Sulphate  cf  Soda. 

70.  Sulphate  of  Potash. 

71.  Muriate  of  Soda. 

72.  Sulphate  of  Mignesia. 

73.  Super  Sulphate  if  Alumir.e  and  y 
Potash. 

74  Muriate  of  Ammonia. 

75.  Acetic  Acid. 

76.  Arsenic  and  arsenous  Acids.  j 

The  above  also  constitute  some  of  the 
substances  used  in  sundry  investigations  ; 
ihe  saline  compounds  are  formed  by  the 
combination  of  sulphuric  or  muriatic  acid 
with  alkaline  or  earthy  bases.  As  these, 
with  other  compounds,  are  employed  on 
some  occasions,  though  rarely  as  tests, 
we  will  not  trouble  the  reader  with  a  fur- 
ther notice  of  them. 

THERMOMETER.  In  the  present  cul- 
tivated state  of  philosophical  knowledge, 
it  can  hardly  be  supposed  that  the  reader 
has  not  seen  a  thermometer.  Minute  de- 
scription is  therefore  unnecessary.  But 
as  the  accurate  construction  and*  subse- 
quent improvement  of  this  instrument 
must  greatly  depend  on  the  knowledge 
which  those  who  use  it  may  possess  of  the 
method  of  making  it;  and  as  we  have  no 
perfect  account  of  this,  there  can  be  no 
doubt  but  a  short  relation  of  the  whole 
process,  from  experimental  knowledge, 
will  be  acceptable. 

The  tubes  may  be  had  at  the  glass- 
house ;  and  the  first  care  of  the  artist 


must  consist  in  examining  whether  then 
cavities  be  equal  or  cylindrical  through- 
out. This  is  done  by  immersing  one  end 
into  mercury,  and  withdrawing  it,  after 
closing  the  otiier  end  with  the  finger.  By 
this  means  a  small  quantity  of  mercury 
will  enter  the  tube,  which  will  occupy  a 
longer  space  the  deeper  the  tube  is  im- 
mersed. Lay  the  tube  horizontally  upon 
a  graduated  rule,  and  observe  the  length 
of  the  mercurial  column  in  different  parts 
of  the  tube,  to  which  it  may  be  made  to 
run  by  inclining  it  more  or  less  If  the 
length  continue  invariably  the  same,  it  is 
a  proof  that  the  tube  is  uniformly  cylin- 
drical ;  but  if  otherwise,  the  diameter  va- 
ries, and  the  tube  cannot  be  used  to  make 
a  good  thermometer,  unless  the  gradua- 
tions in  the  different  parts  of  the  tube  be 
lengthened  or  shortened,  in  proportion  to 
the  measures  ot"  the  mercurial  column. 

Direct  the  flame  of  a  large  candle,  a 
watch-maker's  lamp,  or,  which  is  clean 
liest  and  best  of  all,  a  lamp  with  alcohol, 
upon  one  end  of  the  glass  tube,  by  means 
of  the  blowpipe.  The  extremity  will  soon 
become  red-hot,  and  in  a  state  of  imper- 
fect fusion  Remove  the  tube  from  the 
flame,  and  blow  into  its  other  end,  and 
the  heated  part  will  be  inflated  so  as  to 
form  a  bulb.  This  last  inflation  is  the 
most  difficult  and  laborious  part  ot  the 
business ;  but  it  may  be  performed  with 
great  ease  and  advantage,  by  previously 
fastening  the  neck  of  one  of  the  small  bot- 
tles of  elastic  gum,  or  India  rubber,  about 
the  end  of  the  tube ;  which,  when  the 
other  end  is  ignited,  may  be  pressed  by 
the  hand,  so  as  to  blow  the  bulb  very 
commodiously,  and  without  the  introduc- 
tion of  any  moist  air. 

Immerse  the  open  end  of  the  thermo- 
meter tube  into  some  very  clean  dry  mer- 
cury, that  has  been  boiled,  and  warm  the 
bulb  with  a  candle ;  part  of  the  air  will 
be  immediately  heard  rushing  through 
the  mercury;  withdraw  the  candle,  and 
as  the  bulb  cools  the  mercury  will  rise  in 
the  tube.  This  will  be  facilitated  by  hold- 
ing the  tube  as  near  a  horizontal  position 
as  can  be  done,  without  raising  its  lower 
end  above  the  surface  of  the  mercury.  In 
this  way  the  bulb  will  be  nearly  half  fill- 
ed Without  altering  the  position  of  the 
apparatus,  move  the  whole  so  that  the 
bulb  may  be  held  over  a  candle.  A  small 
candle  newly  snuffed  is  best,  because  of 
the  steadiness  of  its  flame ;  and  it  will  be 
necessary  to  wrap  a  piece  of  paper  round 
the  tube^  to  defend  the  finger  and  thumb 
from  its  heat.  The  mercury  will  soon 
boil,  and  most  of  the  remaining  air  will 
be  heard  escaping  from  the  bulb.  As  sooh 
as  this  escape  has  ceased,  remove  the 


THE 


THE 


bulb  from  the  candle,  atul  the  thermome- 
ter will  be  suddenly  filled  with  mercury 
from  the  vessel. 

Take  the  thermometer  thus  filled  out 
of  the  mercury,  and  wrap  round  its  open 
end  a  piece  of  thin  paper,  in  such  a  man- 
net  as  to  leave  a  cavity  beyond  the  tube, 
at  least  sufficient  to  hold  as  much  mer- 
cury as  the  bulb  contains  ;  secure  this  by 
wrapping  it  tight  with  packthread  about 
the  tube ;  then  put  a  drop  of  mercury 
into  the  proper  cavity,  and  apply  the  bulb 
again  over  the  snuffed  candle,  holding  the 
tube  upright  between  the  finger  and 
thumb,  or  a  pair  of  small  pincers,  at  the 
part  wrapped  with  paper  and  packthread; 
the  mercury  will  soon  boil,  and  about  half 
the  contents  of  the  bulb  will  rush  violent* 
ly  up  the  tube  into  the  paper.  Remove 
the  bulb  from  the  candle,  and  the  mercu- 
ry will  suddenly  return  ;  then  boil  it  again, 
and  repeat  the  operation  till  the  sptedy 
boiling  of  the  mercury,  when  placed  over 
the  candle,  and  the  diminished  noise  and 
agitation,  show,  that  the  whole  has  been 
well  heated,  and  deprived  of  the  air  or 
moisture,  which  might  have  adhered  to  it. 

The  operation.of  boiling  will  fail,  if  the 
mercury  or  the  inside  of  the  hulb  be 
moist;  for  in  this  case  the  bulb  is  usually 
burst  by  the  mercurial  vapour :  the  ex- 
plosion, however,  is  not  dangerous;  it  is 
very  likely  to  happen  with  bulbs  blown 
by  the  mouth,  unless  they  be  kept  some 
weeks  in  a  dry  place  before  they  are  fill- 
ed. The  same  danger  makes  it  prudent 
not  to  boil  the  mercury  strongly  the  first 
or  second  time ;  and  it  is  likewise  of  im- 
portance, to  keep  the  bulb  clear  of  the 
flame,  as  the  contact  of  this  last  against 
the  empty  part  of  the  bulb  would  melt  it, 
and  a  hole  would  be  immediately  made 
by  the  excluded  vapour. 

After  tiie  boiling  is  completed,  plunge 
the  bulb  into  cold  water,  the  temperature 
of  which  is  known.  Melting  ice  or  snow 
(or  snow  and  water)  always  has  the  tem- 
perature of  32°  of  Fahrenheit's  scale. 
Then  take  off  the  paper,  and  put  the  bvdb 
into  the  hand,  and  afterward  into  the 
mouth ;  this  heating  will  cause  some  of 
the  mercury  to  drop  out  of  the  tube  Cool 
it  again  to  32°,  by  immersing  it  in  the 
cold  water,  and  mark  where  the  mercury 
stands.  The  distance  between  this  sta- 
tion and  the  top  of  the  tube  measures  the 
interval  between  freezing  and  blood  heat, 
or  32  and  95,  which  makes  63  degrees  ; 
and  will  consequently  show  whether  the 
degrees  will  be  large'  or  small,  and  what 
extent  the  scale  is  capable  of;  that  is  to 
say,  it  will  show  whether  the  bulb  be  of 
the  proper  size.  This  last,  supposing  the 
judgment  of  the  operator  not  sufficient  to 


proportion  the  bulb  nearly  to  the  tube  and 
the  intended  scale,  might  however  have 
been  more  conveniently  ascertained  after 
the  first  filling,  before  the  boiling  had 
been  undertaken. 

When  the  number  of  degrees  to  which 
the  length  of  the  tube  will  extend  is  thus 
known,  the  operator  must  settle  where- 
abouts he  will  have  the  freezing  point; 
which  may  be  nearer  or  farther  from  the 
bulb,  accordingly  as  he  intends  the  in- 
strument to  be  used,  more  particularly  to 
ascertain  great  degrees  of  heat  or  of  cold. 
At  this  stage  of  the  business,  likewise,  he 
may  heat  the  upper  part  of  the  tube  with 
the  blowpipe,  and  draw  it  out  to  a  fine 
capillary  tube  ready  for  sealing.  The  bulb 
must  then  be  heated  in  the  candle,  till  a 
few  particles  of  mercury  have  fallen  off 
the  top  of  the  tube  ;  and  notice  must  then 
be  taken  how  much  nearer  the  freezing 
point  is  to  the  bulb  than  before ;  which 
may  be  done  by  immersing  it  in  the  melt- 
ing -.now  as  before.  If  it  be  not  as  low  as 
desired,  the  heating  must  be  repeated, 
carefully  observing  not  to  throw  out  too 
much  mercury  at  a  time. 

When  the  due  quantity  of  mercury  is 
thus  adjusted,  two  candles  must  be  pre- 
pared, the  one  to  heat  the  bulb,  and  the 
other  to  close  the  tube.  The  blowpipe 
being  in  readiness,  the  upper  part  of  the 
tube  near  the  flame  of  one  candle,  and 
the  bulb  near  the  flame  of  the  other,  the 
mercury  will  rise,  and  at  last  begin  to 
form  a  globule  at  the  point  of  the  capilla- 
ry tube.  At  this  instant  the  bulb  must 
be  withdrawn  from  the  lower  candle,  at 
the  same  time  that  the  flame  of  the  upper 
is  directed  by  the  blowpipe  upon  the  point 
of  the  tube.  This  last  will  be  immediate- 
ly ignited,  and  will  close  by  the  melting 
of  its  parts,  before  the  mercury  has  per- 
ceptibly subsided.  When  the  mercury 
has  fallen,  this  closure  may  be  rendered 
more  secure  from  accidental  breaking,  by 
fusing  the  whole  point  of  the  tube  till  it 
becomes  round. 

If  this  business  be  properly  done,  the 
mercury  in  the  instrument  thus  filled,  will 
run  backwards  and  forwards  in  the  tube,, 
immediately  upon  inverting  its  situation. 

In  the  original  graduation  of  thermo- 
meters, two  fixed  points  of  temperature 
are  necessary.  These  are  the  freezing 
point  of  water,  or  temperature  of  ice  or 
snow,  at  the  instant  of  formation,  or  rather 
when  it  is  just  beginning  to  liquefy  ;  and 
the  boiling  point  of  water,  or  temperature 
at  which,  under  a  known  pressure,  it  is 
plentifully  converted  into  steam  For  the 
settling  of  the  freezing  point  nothing  more 
is  necessary  than  to  immerse  the  ruermc 
meter  so  deep  in  melting  snow  or  ice,  as 


THE 


THE 


that  the  mercury  may  be  barely  visible 
above  its  surface,  and  carefully  mark  the 
place  at  which  it  stands.  The  boiling- 
point  is  not  quite  so  easily  ascertained; 
crude,  hard,  or  saline  waters  acquire  a 
greater  heat  in  boiling-  than  such  as  are 
purer;  and  the  same  water  will  acquire 
a  greater  heat  under  a  greater  pressure. 
For  this  last  reason,  the  boiling-  point 
should  be  fixed  according-  to  the  decision 
of  the  committee  of  the  Royal  Society  j 
namely,  when  the  barometer  stands  at 
29.8  inches. 

The  best  method  is  to  provide  a  vessel 
somewhat  long-er  than  the  thermometer, 
with  a  cover  and  two  holes  in  it;  one 
about  an  inch  in  diameter  for  the  steam  to 
escape  ;  and  the  other  smaller,  for  the 
thermometer  tube  to  be  fastened  in  it. 
When  this  is  used,  the  thermometer  must 
be  fastened  in  the  cover,  so  that  the  esti- 
mated place  of  the  boiling  point  may  be 
just  above  the  hole.  Water  must  be  put 
into  the  vessel,  not  sufficient  to  touch  the 
bulb  of  the  thermometer  when  the  cover 
shall  be  put  on.  The  vessel  must  then  be 
covered,  a  thin  plate  of  metal  laid  on  the 
steam-hole,  and  the  water  made  to  boil 
by  heat  applied  to  the  bottom  only-  The 
thermometer  will  be  then  surrounded 
with  steam,  which  will  raise  its  tempera- 
ture to  the  boiling-  point ;  and  this  point 
must  be  carefully  marked  on  the  tube 
The  following-  method  may  be  more  con- 
venient to  those  who  are  not  provided 
with  such  a  vessel :  Wrap  several  folds  of 
linen  rags  or  flannel  round  the  tube,  near- 
ly as  high  as  the  supposed  boiling  point ; 
hold  the  ball  of  the  thermometer  in  the 
ascending  current  of  boiling  rain-water, 
about  two  or  three  inches  below  the  sur- 
face ;  pour  boiling  water  on  the  rags  three 
or  four  times,  waiting  a  few  seconds  be- 
tween each  time ;  and  wait  some  seconds 
after  the  last  time  of  pouring  on  water,  in 
order  that  the  water  may  recover  its  full 
strength  of  boiiing,  which  is  considerably 
checked  by  the  pouring  on  the  rags.  The 
place  where  the  mercury  stands  is  the 
boiling-water  point. 

Notwithstanding  the  accurate  adjust- 
ment of  the  fixed  points  of  a  thermome- 
ter, yet,  if  the  tube  be  not  truly  cylindri- 
cal, or  if  the  divisions  be  not  adjusted  to 
the  inequalities  of  its  diameter,  the  er- 
rors at  the  middle,  between  the  two  fixed 
points,  may  amount  to  more  than  a  whole 
degree.  A  small  error  in  the  standing  of 
thermometers  may  be  occasioned  by  the 
varying  pressure  of  the  atmosphere, 
which  alters  the  capacity  of  the  glass ; 
but  it  never  amounts  to  so  much  as  the 
tenth  part  of  a  degree.  Spherical  bulbs 
are  least  subject  to  this. 


Thermometers,  which,  from  the  great 
length  of  their  degrees,  or  for  any  other 
reason,  are  made  to  take  in  but  a  small 
part  of  the  interval  between  the  two  fix- 
ed points,  are  usually  graduated  by  com- 
parison with  a  standard  thermometer. 

The  very  careful  boiling  of  the  mercu- 
ry, as  above  described,  is  absolutely  ne- 
cessary for  such  thermometers  as  are  to 
be  sealed  when  full ;  for  if  there  were 
any  air  or  moisture  left  in  the  bulb,  it 
would  prevent  the  mercury  in  the  tube 
from  descending  into  the  bulb,  so  that  the 
tube  would  continue  always  full.  These 
thermometers  are  undoubtedly  the  best; 
but  the  vacuum  above  the  mercury  does 
not  seem  to  be  an  indispensable  requisite. 
It'  a  clean  dry  tube  be  filled  with  pure 
boiled  mercury,  and  a  small  bulb  be  left 
at  the  top  of  the  tube,  to  contain  common 
air,  in  order  that  its  expansion  or  conden- 
sation, produced  by  the  change  in  the 
mercurial  surface,  may  be  inconsidera- 
ble; there  will  be  few  practical  objec- 
tions against  such  a  thermometer,  more 
especially  if  it  be  a  secondary  instru- 
ment, graduated  by  means  of  a  standard. 
There  are  some  thermometers  made  with 
tubes  so  very  small,  and  bulbs  so  large  in 
proportion  to  them,  that  they  will  not  ad- 
mit of  boiling  the  mercury  in  thero,  but 
are  filled  with  boiled  mercury  by  means 
of  a  condenser.  These  are  necessarily  of 
the  kind  here  mentioned. 

The  thermometers  most  in  use  at  pre- 
sent are  Fahrenheit's,  Reaumur's,  and 
Celsius's.  The  centigrade  thermometer 
of  the  modem  French  writers  is  nothing 
more  than  the  common  Swedish  thermo- 
meter, or  that  of  Celsius  under  a  new 
name.  In  Fahrenheit's  scale,  the  num- 
ber of  degrees  between  the  freezing  and 
boiling-water  point  is  180;  the  freezing 
point  'being  at  32°,  and  the  boiling-water 
point  at  212°,  both  above  0°,  or  the  part 
from  which  the  degrees  are  reckoned  both 
ways.  In  Reaumur's  scale,  the  number 
of  degrees  between  these  two  points  is 
80,  and  the  freezing  point  is  called  0°, 
from  which  the  degrees  are  reckoned 
both  ways.  In  Celsius's  thermometer, 
the  interval  is  divided  into  100°,  and  the 
freezing  point  is  called  0°,  as  in  Reau- 
mur's. To  reduce  these  scales  to  each 
other,  it  must  be  observed,  that  one  de- 
gree of  Fahrenheit's  is  equal  to  four 
ninths  of  a  degree  of  Reaumur,  and  to 
five  ninths  of  a  degree  of  Celsius.  There- 
fore, if  the  number  of  degrees  of  Fahren- 
heit, reckoned  above  or  below  the  freez- 
ing point,  be  multiplied  by  4,  and  divided 
by  9,  the  quotient  will  be  the  correspond- 
ing number  on  Reaumur's  scale.  Or  U 
the  multiplier  5  and  the  divisor  9  be  used? 


TIN 


TIN 


the  quotient  will  give  the  degrees  of  Cel- 
sius's scale.  And,  contrariwise,  if  any 
number  of  degrees,  either  of  Reaumur  or 
Celsius,  be  multiplied  by  9,  and  divided 
by  4,  if  of  Reaumur,  or  by  5,  if  of  Cel- 
sius, the  quotient  will  give  the  degrees  ot 
Fahrenheit,  reckoned  either  above  or  be- 
low the  freezing  point,  as  the  case  may 
he. 

THUNDER.    See  Meteorology. 

TILE,  a  kind  of  thin  brick,  principally 
employed  for  covering  the  roofs  of  houses; 
though  it  is  sometimes  used  for  paving 
cellars,  kitchens,  areas,  Sic. 

Tiles  are  divided  into  various  sorts,  ac- 
cording to  the  purposes  to  which  they  are 
applied.  Thus,  plain  tiles  are  chiefly  us- 
ed for  covering  houses  :  and  they  ought 
to  be  1 0 i  inches  in  length,  6^  in  breadth, 
and  5-8ths  of  an  inch  in  thickness.  Ridge- 
tiles  are  of  a  semi-cylindrical  form,  and,  by 
the  English  statute,  must  be  13  inches  in 
length,  and  also  6|  inches  in  breadth  : 
they  are  chiefly  laid  on  the  ridges  of 
houses.  Corner-tiles  are  first  made  flat, 
in  the  manner  of  plain  tiles,  excepting 
that  they  are  quadrangular ;  the  two  sides 
forming  right  lines ;  and  their  ends, 
arches  of  circles  :  previously  to  burning, 
they  are  bent  on  a  mould,  like  ridge-tiles; 
and  ought  to  be  10£  inches  in  length,  and 
of  a  convenient  size,  being  generally 
placed  on  the  corners  of  roofs. 

TILLAGE.    See  Agricultre. 

TIN.  The  ores  of  this  metal  have  been 
noticed  under  the  article  ore. 

The  method  of  treating  the  ores  of  tin 
in  Cornwall,  England,  is  two-fold.  The 
first  that  we  shall  mention, is  that  to  which 
the  tin-stone  from  the  mines  or  vein-tin  is 
subjected  ;  the  second  is  that  by  which 
the  stream  tin  is  reduced. 

1.  The  vein-tin  is  procured  by  blasting, 
and  when  brought  to  the  top  of  the  pit,  is 
in  fragments  of  various  sizes,  and  mixed 
so  largely  with  quartz,  argillaceous  scliis- 
tus,  granite,  and  other  impurities  as  rarely 
to  contain  more  than  2  per  cent,  of  metal. 
The  first  preparation  that  it  receives,  is 
being  broken  by  hand  hammers,  about 
ihe  size  of  hens'  eggs,  after  which  it  is 
ready  to  be  stamped.  The  stamping-mill 
is  of  the  usual  construction,  (see  the  arti- 
cle Gold,)  except  that  the  stampers  are 
only  three  in  number,  and  in  front  of  the 
trough  or  coffer,  there  is  inserted  a  plate 
of  tin  about  a  foot  square,  pierced  full  of 
holes,  large  enough  to  admit  a  moderate 
sized  knitting-needle;  that  surface  of  the 
plates  which  is  occupied  by  the  rough  ex- 
tremities of  the  holes,  is  placed  on  the 
inside  of  the  trough,  by  which  simple  and 
effectual  contrivance,  the  holes  a/e  pre- 

VOL.  II. 


vented  from  being  plugged  up  by  the  ore. 
In  proportion  as  the  tin-stone  is  reduced 
to  the  proper  degree  of  fineness,  it  passes 
with  the  water  through  these  holes  into 
a  labyrinth,  of  very  simple  construction  ; 
here  the  oxyd  of  tin  is  separated  from 
much  of  the  lighter  impurities,  and  by 
subsequent  washing  on  a  wooden  table, 
it  is  sufficiently  dressed  to  be  sent  to  the 
roasting  furnace  ;  in  this  state  it  is  called 
black  tin,  and  is  generally  mixed  in  con- 
siderable proportion  with  mispickle,  and 
iron  and  copper  pyrites. 

It  is  now  calcined  at  a  low  red-heat  in 
a  large  reverberatory  furnace  for  several 
hours,  in  order  to  volatilize  the  arsenic  and 
burn  off  the  sulphur,  (a  part  of  this  last 
after  being  acidified,  combines  with  the 
oxyds  of  copper  and  iron.)  The  ore 
comes  out  of  the  roasting  furnace,  of  a 
bright  ochery  red  colour,  owing  to  the 
decomposition  and  oxydation  of  the  pyri- 
tes and  mispickel,  the  oxyd  of  tin,  if  the 
operation  has  been  well  performed  having 
undergone  not  the  least  alteration.  The 
ore  is  now  washed  a  second  time,  by  which 
nearly  the  whole  of  the  impurities  are  se- 
parated. The  water  employed  in  this 
process,  being  considerably  impregnated 
with  sulphat  of  copper  is  reserved,  and 
afterwards  decomposed,  by  the  addition 
of  pieces  of  old  iron.  The  next  step  is  the 
reduction,  properly  speaking  ;  for  this 
purpose  a  reverberatory  furnace,  about 
sevai  feet  long  and  three  and  a  half  feet 
wide,  is  charged  with  seven  hundred  cwt. 
of  roasted  ore  mixed  with  one-fifth  of  its 
bulk  of  culm  (Welch  small  coal)  no  lime 
or  any  other  kind  of  flux  being  made  use 
of;  the  fire  is  kept  up  pretty  brisk  for 
about  six  hours,  and  the  tin  in  proportion 
as  it  is  reduced,  sinks  down  to  the  bed  of 
the  furnace,  being  covered  with  a  boiling 
hot  bath  of  black  scoriae. 

At  the  expiration  of  this  period,  the 
furnace  is  tapped  by  means  of  an  iron  bar, 
and  the  hot  metal  flows  into  a  shallow  pit 
at  the  foot  of  the  furnace.  When  the 
whole  of  the  metal  has  run  out,  the  sco- 
riae are  drawn  out  of  the  furnace  with  a 
rake,  and  a  fresh  charge  is  immediately 
thrown  in.  While  the  metal  in  the  pit  is 
red-hot,  it  throws  up  a  quantity  of  slag 
very  rich  in  metal,  which  js  immediately 
returned  into  the  furnace,  and  the  melted 
tin  after  it  has  become  sufficiently  cool, 
is  taken  out  with  iron  ladles  and  poured 
into-  moulds  of  granite,  where  it  consoli- 
dates, each  charge,  affording  on  an  aver- 
age, from  four  to  five  hundred  weight  of 
metal.  The  first  scoria?  are  not  entirely 
exhausted  of  metal,  and  are  therefore 
transferred  to  the  stamp-mill,  and  after- 
3  P 


TIN 


TIN 


wards  washed,  in  order  to  separate  the 
richer  particles,  which  are  then  mixed 
with  the  next  parcel  of  roasted  ore. 

The  pigs  of"  tin  thus  procured  arc  next 
put  without  any  addition,  into  a  small  re- 
verberatory  furnace,  where  they  are  ex- 
posed to  a  very  gentle  heat,  the  purest 
part  of  the  tin,  first  melts  as  it  is  drawn 
off,  farming  the  common  grain  tin  ;  the 
more  refractory  part  containing  a  small 
but  variable  portion  of  copper,  arsenic  and 
iron,  is  then  brought  to  a  state  of  fusion, 
and  cast  into  pigs,  forming  the  common 
or  ordinary  tin. 

2.  The  stream  tin-stone  is  not,  we  be- 
lieve, found  in  any  other  part  of  Europe, 
than  Cornwall,  (Eng.)  It  differs  from  the 
former  in  its  extreme  purity,  and  absolute 
freedom  from  arsenic,  and  in  its  occurring 
in  alluvial  beds.  The  largest  stream-tin 
work  is  at  Carn,  about  two  miles  to  the 
S.  E.  of  Perran,  not  far  from  Redruth.  It 
is  situated  in  a  valley,  through  which 
flows  a  stream,  the  course  of  which  has 
been  turned,  for  the  sake  of  getting  at  the 
treasure  concealed  beneath  its  bed.  The 
workmen  first  dig  through  a  stratum  a- 
bout  fifty  feet  thick  of  clay,  shells  and 
black  earth,  in  which  has  been  found  ha- 
zel nuts,  the  antlers  of  an  animal  of  the 
stag  kind,  a  human  scull,  and  a  copper 
battle-axe  ;  to  this  succeeds  a  layer  of 
rounded  stones,  beneath  which  is  the  bed 
of  tin  ore,  in  grains  and  lumps  of  various 
sizes.  The  thickness  of  this  bed  varies 
from  one  to  five  feet,  but  the  thickest 
part  is  comparatively  the  poorest.  The 
whole  of  the  superincumbent  strata  is  cut 
away,  as  the  workmen  proceed,  so  that 
the  general  appearance  of  the  cavity  is  that 
of  a  vast  gravel  or  sand  pit,  near  half  a 
mile  long,  and  about  two  hundred  feet 
broad,  which  is  kept  clear  of  water  by  the 
powerful  action  of  two  water-mill  pumps. 
The  tin  ore,  as  it  lies  quite  loose,  is  mere- 
ly shovelled  into  barrows,  and  wheeled  to 
the  head  of  the  works,  where  it  is  thrown 
under  a  thin  sheet  of  water  which  washes 
away  the  earth,  leaving  the  pure  ore  be- 
hind. After  this  simple  purification  the 
ore  is  sent  to  St.  Austle,  a  distance  of 
about  twenty  miles,  to  be  smelted.  Here 
all  the  preparation  for  the  furnace,  that 
it  receives  is  being  bruised  and  passed 
through  wire  sieves,  containing  sixteen 
meshes  in  the  square  inch.  The  furnace 
employed  is  called  in  Cornwall,  England, 
a  blowing  furnace,  and  is  in  fact  only  a 
blast  furnace  of  the  simplest  construction, 
about  seven  feet  high,  and  supplied  with 
air  from  two  cylinders,  worked  by  an 
overshot  water-wheel.  The  only  fuel  made 
use  of  is  charcoal,  and  after  the  furnace  is 
fully  heated,  it  is  fed  at  short  intervals 


with  the  following  charge,  viz.  three  or 
tour  shovels-full  of  ore,  aid  two  or  three 
half-bushels  of  charcoal,  no  flux  of  any 
kind  being  employed.  At  the  bottom  of 
the  furnace  is  a  small  channel,  through 
which  the  reduced  tin  is  constantly  flow- 
ing into  a  pit  below,  accompanied  by  a 
small  quantity  of  slag,  which  is  removed 
from  time  to  time,  and  thrown  again  into 
the  furnace.  "When  the  pit  is  full  of  tin, 
it  is  ladled  out  into  an  iron  boiler,  about 
three  feet  in  diameter,  with  a  small  fire 
under  it,  to  keep  the  metal  sufficiently 
fluid  :  two  or  three  large  pieces  of  char- 
coal are  then  laid  upon  the  tin,  and  plung- 
ed to  the  bottom  by  means  of  an  iron  in- 
strument resembling  a  wheel,  with  a  long 
handle  fixed  in  the  axle.  A  violent  ebul- 
lition is  immediately  excited,  and  a  httle 
slag,  which  was  before  mixed  with  the 
metal,  rises  to  its  surface,  and  is  scum- 
med oft*.  In  a  minute  or  two  after,  the 
•metal  is  tried,  by  taking  up  a  ladleful  and 
pouring  again  into  the  mass,  when  if  it 
appears  quite  bright  like  silver,  and  of  an 
uniform  consistence,  the  purification  is 
complete,  and  nothing  more  is  requisite 
than  to  cool  it  to  a  proper  degree,  and  lade 
it  into  the  moulds,  by  which  it  is  formed 
into  pigs,  weighing  from  two  to  three  hun- 
dred weight  each.  If  the  metal  is  pour- 
ed too  hot  into  the  moulds,  it  is  apt  to  be 
brittle.  Good  stream-tin  affords  from  65 
to  75  per  cent,  of  the  very  best  and  purest 
grain  tin. 

Xone  of  the  Cornish  tin  may  be  sold 
till  it  has  been  coined ;  for  this  purpose  a 
small  piece  is  cut  off  from  every  pig  and 
assayed  j  if  it  appears  of  the  requisite  pu- 
rity, it  receives  the  stamp  of  the  Duchy, 
and  pays  to  the  Prince  of  Wales,  as  Duke, 
four  shillings  per  cwt. 

Tin  is  a  metal  of  a  yellowish  white  co- 
lour,considerably  harder  than  lead,scarce- 
lyat  all  sonorous,  very  malleable,  though 
not  very  tenacious.  Wires  cannot  be 
made  of  it;  but  under  the  hammer  it  is 
extended  into  the  leaves,  called  tin  foil, 
which  are  about  one  thousandth  of  an 
inch  thick,  and  might  easily  be  beaten  to 
less  than  half  that  thickness,  if  the  pur- 
poses of  trade  required  it. 

The  process  for  making  tin  foil,  consists 
simply  in  hammering  out  a  number  of 
plates  of  this  metal,  laid  together  upon  a 
smooth  block  or  plate  of  iron.  The  small- 
est sheets  are  the  thinnest.  Its  specific 
g  ravity  is  less  than  that  of  any  other  mal- 
leable metal.  Long  before  ignition,  it  melts 
at  about  the  410th  degree  of  Fahrenheit's 
thermometer,  and  by  a  continuance  of  the 
heat,  it  is  slowly  converted  into  a  white 
powder  by  oxidation.  Like  lead,  it  is 
brittle  when  heated  almost  to  fusion,  and 


TIN 


TIN 


exhibits  a  grained  or  fibrous  texture,  if 
broken  by  the  blow  of  a  hammer  ;  it  may 
also  be  granulated  by  agitation,  at  the 
time  of  its  transition  from  the  fluid  to  the 
solid  state.  The  oxyd  of  tin  resists  fu- 
sion more  strongly,  than  that  of  any  other 
metal :  from  which  property  it  is  useful, 
to  form  an  opake  white  enamel,  when 
mixed  with  pure  glass  in  fusion.  The 
brightness  of  its  surface  when  scraped, 
soon  goes  off  by  exposure  to  the  air  ;  but 
it  is  not  subject  to  rust  or  corrosion,  by 
exposure  to  the  weather. 

A  preparation  of'the  oxyd  of  tin  is  made 
for  the  purpose  of  giving  the  highest  po- 
lish to  steel,  and  to  glass  and  metal  mir- 
rors, which  is  called  tin  putty.  It  is  pre- 
pared according  to  Beaume  in  the  follow- 
ing way. 

Some  tin  is  melted  in  an  iron  vessel, 
with  a  low  red  heat,  and  the  oxyd  that 
forms  on  the  surface,  is  successively  re- 
moved till  enough  of  it  is  procured.  This 
is  then  spread  on  a  red-hot  muffle,  and 
heated  for  half  an  hour,  with  frequent 
stirring,  to  complete  the  calcination  of 
any  particles  of  tin,  that  may  be  entangled 
in  the  oxyd.  When  cold  it  is  powdered 
and  sifted,  and  the  finer  part  is  again  cal- 
cined for  six  or  seven  hours  on  a  muffle, 
with  a  stronger  heat,  till  it  becomes  al- 
most white,  and  considerably  hard,  and 
in  this  state  it  forms  the  tin  putty. 

This  substance  is  made  in  this  country 
in  a  similar  way.  For  the  finest  putty  the 
purest  grain  tin  is  employed,  which  is 
calcined  in  a  muffle,  finely  levigated  and 
washed.  This  is  nearly  white,  but  the 
ordinary  and  cheaper  sorts  are  browner, 
and  are  made  by  calcining  old  pewter,  or 
a  mixture  of  tin  and  lead,  or  any  other 
alloy  of  these  metals,  which  when  in  mix- 
ture, oxydate  still  more  readily  than  ei- 
ther of  the  metals  separately,  and  will 
easily  take  fire,  as  soon  as  the  heat  is  rais- 
ed to  redness.  As  the  oxyd  of  lead  is  very 
fusible,  and  the  oxyd  of  tin  very  little  so, 
the  subsequent  calcination  in  this  case,  is 
probably  made  at  a  lower  heat,  than  when 
pure  tin  is  used,  otherwise  the  whole 
would  run  into  a  dense  glass.  This  pre- 
paration must  not  be  confounded  with  gla- 
zier's putty,  which  is  only  chaik  beat  up 
with  linseed  oil. 

Concentrated  sulphuric  acid,  assisted 
by  heat,  dissolves  half  its  weight  of  tin, 
at  the  same  time  that  sulphureous  gas 
escapes  in  great  plenty.  By  the  addition 
of  water,  an  oxyd  of  tin  is  precipitated. — 
Sulphuric  acid,  slightly  diluted,  likewise 
acts  upon  the  metal ;  but  if  much  water 
be  present,  the  solution  does  not  take 
place. 

Nitric  acid  arid  tin  combine  together 


very  rapidly,  without  the  assistance  of 
heat.  Most  of  the  metal  falls  down  in  the 
form  of  a  white  oxyd,  extremely  difficult 
of  reduction  ;  and  the  small  portion  of  tin, 
which  remains  suspended,  does  not  afford 
crystals,  but  falls  down,  for  the  most  part, 
upon  the  application  of  heat,  to  inspissate 
the  fluid. 

The  muriatic  acid  dissolves  tin  very 
readily,  at  the  same  time  that  it  becomes 
of  a  darker  colour,  and  ceases  to  emit 
fumes.  A  slight  effervescence  takes  place 
with  the  disengagement  of  a  fetid  inflam- 
mable gas.  Muriatic  acid  suspends  half  its 
weight  of  tin,  and  does  not  let  it  fall  by 
repose.  It  affords  permanent  crystals  by 
evaporation.  If  the  tin  contains  arsenic, 
it  remains  undissolved  at  the  bottom  of 
the  fluid.  Recent  muriate  of  tin  is  a  very 
delicate  test  of  mercury.  Mr.  Chenevix 
says,  if  a  single  drop  of  a  saturated  solu- 
tion of  neutralized  nitrate  or  muriate  of 
mercury,  be  put  into  500  grains  of  water, 
a  few  drops  of  solution  of  muriate  of  tin, 
will  render  it  a  little  turbid,  and  of  a  smoke 
gray.  He  adds,  that  the  effect  is  per- 
ceptible, if  ten  times  as  much  water  be 
added. 

Oxygenized  muriatic  acid  dissolves  tin 
very  readily,  and  without  sensible  effer- 
vescence.  The  solution  itself  does  not 
appear  to  differ  from  the  foregoing. 

A  muriate  of  tin  at  a  much  higher  de« 
gree  of  oxydizement,  and  very  different 
in  its  properties,  may  be  formed  by  an  in- 
direct process. 

When  equal  parts  of  an  amalgam  of  tin 
and  mercury,  and  of  corrosive  muriate  of 
mercury,  are  triturated  together,  and  the 
mixture  exposed  to  distillation  in  a  retort, 
by  a  very  gentle  heat,  a  colourless  fluid 
first  comes  over.  This  is  followed  by  a 
thick  white  fume,  which  becomes  con- 
densed into  a  transparent  liquor,  called 
the  fuming  liquor  of  Libavius,  on  account 
of  the  copious  fumes  it  emits,  when  the 
vessel  that  contains  it  is  opened.  On  ac- 
count of  the  considerable  volatility  of  this 
liquid,  it  rises  partly  in  the  form  of  flow- 
ers to  the  top  of  the  bottle,  into  which  it 
is  put ;  so  that  in  the  course  of  several 
months,  it  becomes  entirely  closed. 

The  residue,  after  the  "distillation  by 
which  the  fuming  liquor  of  Libavius  is 
produced,  consists  of  tin  combined  with 
the  muriatic  acid,  calomel  and  running 
mercury,  which  sublime  into  the  roof  and 
neck  of  the  retort ;  and  at  the  bottom  is 
found  an  amalgam  of  mercury  and  tin, 
covered  with  a  saline  combination  of  mu- 
riatic acid  with  tin,  and  such  other  metaU 
as  the  tin  may  have  been  adulterated  with, 
Much  information  may  be  derived  from 
the  foregoing  experiments  of  Mr.  Adet, 


TJX 


TIN 


respecting*  the  phenomena  produced, 
when  tin  is  dissolved  in  aqua  regia. 

Proust  makes  this  Aiming-  liquor  with- 
out any  amalgam.  He  mixed  24  ounces 
of  corrosive  muriate  of  mercury,  with  8 
ounces  of  powdered  tin,  and  from  these 
obtained  9  ounces  of  the  liquor  of  Liba- 
vius.  As  a  great  excess  of  pure  and 
oxyded  tin  was  found  in  the  residuum,  he 
tried  the  proportion  of  52  ounces  to  8,  but 
this  gave  him  only  10  ounces  of  the  li- 
quor. 

Pelletier  prepared  it  by  passing  oxyge- 
nized muriatic  acid  gas,  through  a  solu- 
tion of  muriate  of  tin,  and  expelling  the 
excess  of  muriatic  acid  by  heat. 

Aqua  regia,  consisting  of  two  parts  ni- 
tric and  one  muriatic  acid,  combines  with 
tin,  with  effervescence,  and  the  develope- 
ment  of  much  heat.  In  order  to  obtain  a 
permanent  solution  of  tin  in  this  acid,  it 
is  necessary  to  add  the  metal,  by  small 
portions  at  a  time  ;  so  that  the  one  por- 
tion may  be  entirely  dissolved  before  tlie 
next  piece  is  added.  Aqua  regia,  in  this 
manner,  dissolves  half  its  weight  of  tin. 
The  solution  is  of  a  reddish  brown,  and 
in  many  instances,  assumes  the  form  of  a 
concrete  gelatinous  substance.  The  ad- 
dition of  water,  sometimes  produces  the 
concrete  form  in  this  solution,  which  is 
then  of  an  opal  colour,  on  account  of  the 
oxyd  of  tin,  diffused  through  its  sub- 
stance. 

The  solution  of  tin  in  aqua  regia,  is  used 
by  dyer's  to  heighten  the  colours  of  co- 
chineal, gum  lac,  and  some  other  red 
tinctures,  from  crimson  to  a  bright  scarlet, 
in  the  dyeing  of  woollens. 

The  solution  actually  made  by  the 
scarlet  dyer's,  and  called  by  them  spirit, 
is  prepared  with  that  species  of  dilute  ni- 
tric acid,  termed  single  aqua  fortis,  to 
every  pound  of  which  are  added,  from  one 
to  two  ounces  of  common  salt,  or  sal-am- 
moniac. The  acid  thus  prepared,  will 
dissolve  about  an  eighth  of  its  weight  of 
tin,  which  is  previously  granulated  by 
being  poured,  when  melted,  into  water 
briskly  agitated  by  rods.  This  acid  is 
still  further  diluted,  and  the  heat  of  solu- 
tion is  checked  by  setting  it  in  cold  water, 
and  adding  the  water  very  gradually.  The 
process  of  solution  is  thus  protracted  to 
two  or  three  days. 

The  acetous  acid  scarcely  acts  upon 
tin.  The  operation  of  other  acids  upon 
this  metal  has  been  little  inquired  into. 
Phosphat,  fluat,  and  borat  of  tin  have  been 
formed  by  precipitating  the  muriat  with 
the  respective  neutral  salts. 

Tin  is  soluble  in  the  acid  of  tartar,  and 
this  solution  is  of  importance  in  manufac- 
ture, as  it  is  the  method  by  which  wet 


tinning  is  performed  on  copper  and  brass. 
Pins  are  whitened  in  this  manner,  but  by 
a  compound  menstruum. 

This  process  is  easily  performed :  a  so- 
lution of  about  one  part  of  cream  of  tar- 
tar, two  parts  of  alum,  and  as  much  com- 
mon salt,  is  made  in  a  moderate  quantity 
of  water,  and  tin  filings,  or  granulated  tin 
is  thrown  in,  and  the  liquor  boiled.  The 
pins,  which  are  made  of  brass  wire,  and 
perfectly  bright,  are  then  put  in,  and  alter 
remaining  in  the  boiling  liquor  for  a  time, 
they  are  completely  covered  with  a  beau- 
tiful white  uniform  coating  of  tin,  which 
is  the  state  in  which  they  are  used. 

It  is  not  necessary  to  employ  this  mix- 
ture of  salts  for  the  mere  tinning  of  cop- 
per or  brass.  Either  of  these  three  salts 
singly  with  tin  filings  will  answer  the  pur- 
pose, but  cream  of  tartar  gives  a  duller 
and  more  leaden  looking  tinning,  and  alum 
on  the  other  hand  gives  a  very  fine  silver 
white  but  without  gloss,  so  that  the  mix- 
ture above-mentioned  is  found  to  produce 
tlie  most  desirable  hue. 

In  a  chemical  point  of  view  this  opera- 
tion is  curious,  and  appears  to  present  a 
contradiction  to  the  usual  laws  of  affinity, 
for  when  tin  is  immersed  in  a  common  so- 
lution of  copper,  it  precipitates  most  of 
the  copper  in  the  metallic  state. 

The  circumstances  requisite  to  produce 
a  precipitate  of  metallic  tin  on  copper, 
have  been  examined  in  an  able  set  of  ex- 
periments by  Professor  Gadoiin,  a  Swe- 
dish chemist,  an  account  of  which  is  in- 
serted in  the  Stockholm  Transactions,  for 
1788,  to  which  are  added  some  other  ex- 
periments and  remarks  by  Baron  de  Ged- 
da.  It  is  to  be  observed,  that  the  circum- 
stances relating  to  the  oxygenation  of  me- 
tals in  their  solutions  in  acids  were  very 
incompletely  known  at  that  time,  so  that 
we  may  now  account  for  phenomena, 
which  must  have  been  inexplicable  at  that 
period.  The  facts,  however,  canrot  vary, 
and  are  always  valuable.  This  chemist 
chiefly  confined  himself  to  the  action  of  a 
single  salt,  namely  tartar,  or  its  acid. 

Earthy  substances  do  not  appear  to  af- 
fect this  metal  in  the  dry  way.  It  deto- 
nates very  rapidly  with  nitre,  and  becomes 
converted  into  an  oxide,  which  partly 
combines  with  the  alkali.  All  the  sul- 
phate are  decomposed  by  tin.  The  tin 
becomes  oxided,  and  the  sulphuric  acid 
converted  into  sulphur,  which  forms  a  sul- 
phuret  with  the  alkali,  or  earth  of  the 
salt,  and  dissolves  part  of  the  oxide. 

Sal  ammoniac  is  very  readily  decom- 
posed by  tin. 

If  the  crystals  of  the  saline  combination 
of  copper  with  the  nitric  acid  be  grossly 
powdered,  moistened,  and  rolled  up  in 


TIN 


TIN 


tinfoil,  the  salt  deliquesces,  nitrous  fumes 
are  emitted,  the  muss  becomes  hot,  and 
suddenly  takes  fire.  In  this  experiment 
the  rapid  transition  of  the  nitric  acid  to 
the  tin,  is  supposed  to  produce  or  devt- 
lope  heat  enough  to  set  fire  to  the  nitric 
salts ;  but  by  what  particular  changes  of 
capacity  has  not  been  shown. 

If  sulphur,  in  powder,  be  added  to 
about  five  times  its  weight  of  melted  tin, 
the  two  substances  combine,  and  form  a 
black  compound,  which  takes  fire,  and  is 
much  less  easily  filled  than  tin  itself. 
The  mass  is  brittle,  and  of  a  needled  tex- 
ture. 

A.  beautiful  golden  coloured  species  of 
sulphuret  of  tin  has  long  been  known  in 
the  arts,  under  the  name  of  aurum  musi- 
vum, or  mosaicum  (Mosaic  gold).  It  is 
Ml  the  form  of  a  scaly  mass,  sometimes 
crystallized  in  six-sided  plates,  very  soft 
and  glossy  to  the  touch,  readily  rubbed 
down  between  the  fingers,  and  when  the 
colour  is  brought  out  by  a  little  friction, 
having  a  fine  golden  metallic  lustre.  It  is 
still  prepared  in  pretty  large  quantities 
by  some  artists,  and  is  supposed  to  be 
used  principally  in  artificial  bronzing  and 
other  ornamental  purposes.  It  was  for- 
merly employed  in  medicine.  A  great 
number  of  receipts  have  been  given  lor 
preparing  it,  most  of  which  succeed  near- 
ly equally  well,  provided  the  same  atten- 
tion to  management  of  the  heat,  &c.  be 
observed.  It  is  also  interesting  to  expe- 
rimental chemistry,  and  its  properties 
have  been  examined  by  several  excellent 
chemists,  among  whom  may  be  enumera- 
ted Mr.  Woulfe,  the  Marquis  de  Bullion, 
and  M.  Pelletier. 

The  old  process  for  aurum  musivum, 
and  which  is  one  of  the  best,  is  the  fol- 
lowing ;  as  contained  in  the  London  Dis- 
pensatory. 

Take  12  oz.  of  tin,  7oz.of  flowers  of 
sulphur;  sal-ammoniac  and  quicksilver, 
of  each  6oz. ;  melt  the  tin  by  itself,  add 
to  it  the  quicksilver,  and  when  the  amal- 
gam is  cold  reduce  it  to  powder,  and  mix 
it  with  the  sulphur  and  sal  ammoniac,  and 
sublime  the  whole  in  a  glass  matrass, 
standing  in  a  sand  bath.  Apply  a  gentle 
fire  for  some  time,  till  the  white  fumes 
which  arise  copiously  at  first,  begin  to 
abate,  then  raise  the  fire  till  the  sand  be- 
comes red  hot,  and  keep  it  at  this  point, 
neither  increasing  nor  diminishing  it,  for 
a  considerable  time,  according  to  the 
quantity  of  the  materials,  till  you  judge 
the  operation  to  be  completed.  The  ma- 
trass being  broken  when  cold,  the  mosaic 
gold  is  found  at  the  bottom,  and  above  it 
a  sublimed  substance,  the  composition  of 
which  will  be  presently  mentioned, 


The  mosaic  gold  therefore  is  not  a  sub. 
limate,  but  is  a  fixed  substance,  and  it 
cannot  be  raised  by  heat  unchanged.  It 
weighs  considerably  more  than  the  tin 
employed,  but  the  actual  product  is  ex- 
tremely uncertain.  A  good  deal  of  care 
is  required  in  managing  the  fire,  for  if  too 
slack,  none  of  the  mosaic  gold  will  be 
formed,  and  if  urged  beyond  a  moderate 
redness  it  is  again  decomposed  into  a  dark 
sulphuret  of  tin,  totally  without  lustre. 
The  proportion  of  the  ingredients  are  va- 
riously given.  Formerly,  equal  parts  of 
all  the  substances  were  empoyed,  but  they 
may  be  reduced  to  the  proportions  here 
given  without  diminishing  the  product. 

As  soon  as  the  ingredients  are  mixed, 
an  odour  of  sulphuretted  hydrogen  is 
given  out,  which  increases  rapidly  as  heat 
is  applied ;  and  if  the  process  be  perform- 
ed in  a  retort,  with  a  receiver  attached  to 
it,  a  quantity  of  hydrosulphuret  of  ammo- 
nia or  volatile  liver  of  sulphur,  comes 
over,  which  condenses  in  the  extremity 
of  the  receiver,  partly  as  a  liquid,  and 
partly  in  beautiful  crystalline  needles. 
The  sublimate  wh  -ch  is  formed  above  the 
aurum  musivum,  and  which  is  much  less 
volatile  than  the  ammoniacal  hydrosul- 
phuret, is  an  extremely  compound  sub- 
stance, (in  the  usual  way  of  preparing  it) 
consisting  chiefly  of  cinnabar,  of  muriated 
ammonia,  and  some  muriat  of  tin,  from 
which  by  a  fresh  sublimation  an  addition- 
al quantity  of  the  aurum  musivum  may  be 
obtained.  This  latter  appears  to  be  con- 
tained in  the  first  sublimate,  and  indeed 
may  often  be  found  interspersed  in  it  in 
shining  hexagonal  plates,  but  as  aurum 
musivum  alone  cannot  be  sublimed,  this 
portion  is  supposed  to  be  formed  by  the 
muriat  of  tin  and  sulphur  combining  in 
the  act  of  volatilization. 

Tin  unites  with  most  of  the  metals,  and 
some  of  these  alloys  are  much  used  in  the 
arts.  Of  these  the  most  important  are  : 
the  alloy  of  tin  and  copper,  with  other  ad- 
ditions, which  forms  bronze,  bell  metal, 
speculum  metal,  &c. — The  alloy  of  tin 
and  lead  in  equal  parts,  which  forms  the 
common  plumber's  solder :  the  alloy  of 
tin,  lead,  and  bismuth,  which  forms  the 
very  fusible  compounds  described  under 
Bismuth  :  the  amalgam  of  tin  and  mer- 
cury used  in  silvering  mirrors,  the  pro- 
cess of  which  is  mentioned  under  the  ar- 
ticle Glass,  and  the  alloys  commonly 
called  pewter. 

Pewter  was  formerly  more  extensively 
used  than,  perhaps,  any  other  metallic  al- 
loy, being  the  common  material  for  plates, 
dishes,  and  other  domestic  utensils,  but 
its  use  is  now  almost  universally  super- 
seded by  potten-,  which  is  lighter,  more 


TIN 


TIT 


easily  kept  clean,  and  cheaper,  though 
less  durable.  The  name  of  pewter  has 
been  given  to  any  malleable  white  alloy, 
into  which  tin  largely  enters,  and  its  com- 
position is  so  various,  that  hardly  any  two 
manufacturers  employ  precisely  the  same 
ingredients,  and  in  the  same  proportion. 
The  finest  kind  of  pewter  contains  no  lead 
whatever,  but  consists  of  tin  with  a  small 
alloy  of  antimony,  and  sometimes  a  little 
copper.  Wallerius  gives  the  proportions 
of  12  parts  of  tin,  1  of  antimony,  and 
about  one-forty-eighth  of  copper.  A  very 
fine  metal  is  made  of  100  putts  of  tin,  8 
of  antimony,  1  of  bismuth,  and  4  of  cop- 
per. The  use  of  these  additions  to  the 
tin  is  to  harden  it,  and  preserve  its  white- 
ness; and  this  fine  kind  of  pewter  takes  a 
Very  high  polish,  has  a  beautiful  silvery 
lustre,  and  is  not  readily  tarnished.  Tin, 
with  a  little  zinc  or  brass,  makes  a  very 
fine,  hard  alloy.  In  all  these  superior 
kinds  of  pewter,  the  tin  jbrms  by  far  the 
greater  part  of  the  mixture. 

It  is  to  be  observed,  that  the  antimony 
is  so  intimately  united  to  the  tin,  that  it  is 
not  volatilized  when  strongly  heated,  or 
only  in  a  very  small  degree,  and  it  is  not 
easily  dissolved  by  any  weak  acid,  so  that 
there  is  no  danger  of  producing  the  com- 
mon effects  of  this  metal  in  employing 
this  kind  of  pewter.  There  is  a  natural 
limit  to  the  use  both  of  all  the  brittle  me- 
tals,  and  of  copper  in  alloying  tin,  which 
is  the  brittlcness  which  they  impart  10  the 
alloy  when  they  exceed  certain  propor- 
tions. But  it  is  not  so  with  lead,  which 
may  be  mixed  with  tin  in  any  proportion, 
and  the  alloy  will  remain  perfectly  mal- 
leable; and  this  with,  or  without  other 
smaller  additions,  forms  the  ordinary 
pewter,  such  as  is  used  for  measures  for 
liquor,  and  many  similar  purposes,  and 
in  other  countries  of  Europe,  for  many 
other  domestic  uses.  As  lead  is  by  much 
the  cheapest  of  the  two  metals,  it  is  the 
interest  of  the  manufacturer  to  employ  it 
in  as  large  a  proportion  as  possible  ;  but 
as  much  danger  to  health  may  be  appre- 
hended from  this  noxious  metal,  this  sub- 
ject was  examined  particularly  by  a  com- 
mission from  the  French  government  of 
some  very  able  chemists.  These  gentle- 
men found,  that  when  wine  or  vinegar  is 
allowed  to  stand  in  vessels  composed  of 
an  alloy  of  lead  and  tin  in  different  pro- 
portions, the  tin  is  first  dissolved,  that  the 
lead  is  not  sensibly  oxydated  by  these  li- 
quors, except  at  the  line  of  contact  of  the 
air  and  the  liquor,  and  that  no  sensible 
quantity  of  lead  is  dissolved  even  by  vine- 
gar after  standing  for  some  days  in  ves- 
sels that  contained  no  more  than  about 
18  per  cent,  of  lead.    Therefore,  as  no 


noxious  effect  is  produced  by  the  very 
minute  quantity  of  tin  which  is  dissolved, 
a  pewter  may  be  considered  as  perfectly 
safe  which  contains  about  80  or  82  per 
cent,  of  tin  ;  and  where  the  vessels  are 
employed  merely  for  measures,  a  much 
less  proportion  of  tin  may  be  allowed. 
But  the  common  pewter  of  Paris  was 
found  to  contain  no  more  than  about  25 
or  30  percent,  of  tin,  and  the  remainder 
was  lead.  The  specific  gravity  of  a  mix- 
ture of  tin  and  lead  is  less  than  the  mean 
specific  gravity  of  t^e  same  proportion  of 
the  two  metals  separately ;  consequently, 
the  bulk  of  the  alloy  is  greater  than  the 
hulks  of  the  metals  before  union,  which 
is  the  contrary  to  what  happens  in  most 
other  alloys.  This  alloy,  when  in  equal 
parts,  forms  also  the  common  plumbers' 
solder.  When  melted,  it  oxydates  at  its 
surface  with  great  rapidity,  much  more 
than  either  of  the  metals  separately, 
and  this  oxyd  is  the  basis  of  the  finest 
Enamel  white. 

The  uses  of  tin  are  considerable.  It  is 
employed  for  many  purposes  in  fine  leaf, 
about  the  thickness  of  writing  paper,  when 
it  is  called  Tin  fail.  This  is  made  from 
the  very  finest  tin,  which  is  first  cast  into 
an  ingot,  then  laminated  to  a  moderate 
extent,  and  afterwards  beat  out  with  a 
hammer,  with  very  great  manual  labour 
and  skill,  till  it  is  brought  to  the  requisite 
thickness,  and  esrtended  perfectly  uni- 
formly without  any  flaw  or  break.  The 
other  uses  of  tin  are,  very  largely,  for  tin- 
ning iron  and  copper,  in  pewter,  solder, 
and  other  alloys  ;  and  the  salts  of  this  me- 
tal are  employed  in  dyeing. 

When  tin  is  heated  with  phosphoric 
and  charcoal,  the  metal  appears  to  be 
very  little  changed.  A  combination,  how- 
ever, seems  to  take  place,  for  the  phos- 
phorus burns  on  the  surface  of  the  metal 
when  heated  by  the  blowpipe.  If  small 
pieces  of  phosphorus  be  thrown  on  tin  in 
fusion,  it  will  take  up  from  15  to  20  per 
cent,  and  form  a  silvery  white  phosphu- 
ret  of  a  foliated  texture,  and  soft  enough 
to  be  cut  with  a  knife,  though  but  little 
malleable.  This  phosphuret  may  be  form- 
ed likewise  by  fusing  tin  filings  with  con^ 
crete  phosphoric  acid. 

TINCAL.    See  Borax. 

TIN-GLASS.    See  Bismuth. 

TINNING  OF  IRON.    See  Inox. 

TINNING  OF  BRASS,  COPPER,  &c. 
See  Tin. 

TITANIUM. — This  metal  was  found  in 
the  state  of  oxide  combined  with  others, 
in  the  vale  of  Manachan,  in  Cornwall,  En- 
gland, whence  it  was  named  man achanite, 
or  oxide  of  titanium  combined  with  iron. 
Klaproth  found  it  in  an  ore  named  titan- 


TOO 


TOO 


ile,  or  oxide  of  titanium,  combined  with 
lime  and  silex.  It  exists  also  in  an  ore 
called  red  schorl  of  Hungary,  or  red  oxide 
of  Titanium. 

It  is  extremely  difficult  to  reduce  the 
oxide  of  titanium  to  the  metallic  state. 
However,  the  experiments  of  Klaproth, 
Hecht,  and  Vauquelin,  have  proved  its  re- 
ducibility. 

According  to  the  two  latter,  one  part  of 
the  oxide  of  titanium  is  to  be  melted  with 
six  of  potash  ;  the  mass  when  cold  is  to 
be  dissolved  in  water.  A  white  precipi- 
tate will  be  formed,  which  is  carbonate  of 
titanium.  This  carbonate  is  then  made 
into  a  paste  with  oil,  and  the  mixture  is 
put  into  a  crucible  filled  with  charcoal 
powder  and  a  little  alumina.  The  whole 
is  Chen  exposed  for  a  few  hours  to  the  ac- 
tion of  a  strong  heat.  The  metallic  tita- 
nium will  be  found  in  a  blackish  puffed 
up  substance,  possessing  a  metallic  ap- 
pearance. 

Titanium  has  only  been  obtained  in  ve- 
ry small  agglutinated  grains.  It  is  of  a 
red  yellow  and  crystalline  texture,  brit- 
tle, and  extremely  refractory.  Its  speci- 
fic gravity  is  about  4.2;  when  broken 
with  a  hammer  while  yet  hot  from  its  re- 
cent reduction,  it  shows  a  change  of  co- 
lours of  purple,  violet,  and  blue;.  In  very 
intense  heat  it  is  volatilized.  Most  of  the 
acids  have  a  striking  action  on  this  metal. 
Nitric  acid  has  little  effect  upon  it.  It  is 
very  oxidable  by  the  muriatic  acid.  It  is 
not  attacked  by  the  alkalies.  Nitro-mu- 
riatic  acid  converts  it  into  a  white  powder. 
Sulphuric  acid  when  boiled  upon  it  is 
partly  decomposed.  It  is  one  of  the  most 
infusible  metals.  It  does  not  combine 
with  sulphur,  but  it  may  be  united  to 
phosphorus.  It  does  not  alloy  with  cop- 
per, lead,  or  arsenic  ;  but  combines  with 
iron.  See  Chenevix's  paper  in  Nichol- 
son's Journal,  v.  134,  and  Accum. 

TOBACCO,  various  manufactures  of. 
See  Snuff,  S*c. 

TOBACCO  PIPES,  how  made.  See 
Pottery. 

TOMBAC,  a  white  alloy  of  copper  with 
arsenic,  which  is  sometimes  called  white 
copper.    See  Copper. 

TOOL,  a  general  term,  denoting  any 
small  implement,  which  is  used  both  for 
manufacturing  other  complex  instruments 
or  machines,  and  also  those  employed  in 
the  mechanical  arts. 

Tools  are  divided  into  edged-tools, 
spring-tools,  pointed-tools,  Sec.  But,  con- 
sistently with  the  advanced  state  of  the 
present  work,  we  shall  only  give  an  ac- 
count of  a  patent,  granted  in  January, 
1795,  to  Mr.  Arnold  Wilde,  for  making 
plane-irons,  sickles,  scythes,  drawing- 


knives,  and  other  kinds  of  edged-tools, 
from  a  preparation  of  cast-steel  and  iron, 
incorporated  by  means  of  fire....He  directs 
a  piece  of  wrought-iron  to  be  previously 
heated  in  the  fire,  and  hammered ;  after 
which  it  should  be  formed  of  the  rccpii- 
site  size  :  it  is  then  to  be  fixed  in  a  mould 
of  proper  dimensions,  and  in  such  a  direc- 
tion that,  when  the  cast-steel  is  poured 
into  the  latter,  the  iron  may  settle  in  the 
middle,  or  on  either  side... .Next,  the  steel 
must  be  melted  in  a  crucible  exposed  to 
a  strong  fire  ;  and,  when  it  is  nearly  in  a 
fluid  state,  the  iron  should  be  prepared 
in  a  welding  heat.    After  clearing  it  from 
scales,  or  other  extraneous  matters,  the 
iron  is  again  to  be  fixed  in  the  mould, 
and  the  fluid  steel  poured  into  the  vacan- 
cy left  for  that  purpose  ;  when  the  whole 
will  be  united  into  one  solid  mass....The 
various  tools,  above-mentioned,  may  then 
be  made  of  such  compound  metal  in  the 
usual  manner ;   or  by  any  method  that 
should  be  deemed  most  convenient  to  the 
workman,  or  manufacturer. 

The  following  remarks  on  the  subject 
of  Pettibone's  patent  for  making  edge- 
tools,  accompanying  a  certificate  of  seve- 
ral eminent  gentleman  of  our  city,  may 
be  here  noticed. 

From  the  "  Useful  Cabinet,"  published  at 
Boston,  in  monthly  numbers, for  the  Mas- 
sachusetts Association  of  Inventors,  and 
Patrons  of  Useful  Jirts,  for  the  year 
1808,  commenced  at  page  26. 
The  superiority  of  edge-tools,  made  of 
cast-steel,  is  too  well  known  to  need  any 
recommendation.  The  art  of  welding  the 
best  kind  of  cast-steel  to  iron,  without  in- 
juring its  texture,  is  an  American  disco- 
very.   Mr.  Daniel  Pettibone,  of  Roxbury, 
Massachusetts,  is  the  inventor ;  for  which 
he  has  a  patent,  dated  March,  1806.  This 
is  a  valuable  invention  ;  as  tools  made  of 
cast-steel  welded  to  iron,  by  his  process, 
sufficiently  prove. 

Although  we  have  tools  imported  from 
England,  which  are  said  to  be  cast-steel 
welded  to  iron  ;  yet,  according  to  the  ac- 
count of  sir  T.  Frankland,  communicated 
in  1795,  to  the  lloyal  Society  of  London, 
it  appears  that  the  cast-steel  which  they 
weld  to  iron  is  a  soft  kind  ;  little  better,  if 
any,  than  common  steel.  For  lie  says, 
that  the  heat  which  they  find  necessary 
to  weld  their  cast-steel  would  either  melt 
the  best  kind,  (such  as  Mr.  Pettibone 
uses)  or  render  it  unable  to  bear  the 
hammer;  in  which  case,  the  goodness  of 
the  steel  would  be  wholly  ruined :  so 
that  Mr.  Pettibone's  discovery  may  be 
justly  considered  a  great  and  valuable 
improvement,  in  extending  the  use  of  the 


TOU 


best  cast-steel  to  those  tools  which  re- 
quire a  part  of  them  to  be  iron  ;  and  this 
too  without  the  least  injury  to  the  good- 
ness of  the  steel  which  it  possesses  be- 
fore it  is  welded.  His  process  is  simple, 
not  expensive,  and  easy  to  be  understood. 
Edge-tool  makers  will  find  it  advantage- 
ous to  them  to  obtain  of  him  a  right  to 
use  this  valuable  art. 

At  the  desire  of  Mr.  Pettibone,  we 
have  evidenced  and  examined  his  pro- 
cess for  welding  iron  and  cast-steel  toge- 
ther, and  have  seen  several  of  the  edged 
tools  formed  from  the  welded  masses,  by 
means  of  rollers,  as  described  in  his  spe- 
cification, which  appear  to  us  to  be  very 
good  ;  and  we  have  no  hesitation  in  de- 
claring, that  we  consider  this  invention  of 
Mr.  Pettibone,  as  likely  to  be  of  great  be- 
nefit to  the  public,  and  well  worthy  of 
their  patronage. 

R.  Patterson, 
Joseph  Cloud, 
Adam  Eckfeldt, 
Oliver  Evans. 
Philadelphia,  June  20,  1812. 
TORRE  FACTION,   an  operation  of 
roasting,  by  which  ores  are  deprived  of 
sulphur,  arsenic,  &.c.  which  they  might 
contain,  and  sundry  articles,  as  rhubarb 
rendered  crisp.    See  Ore. 

TORTOISE  SHELL,  imitation  of  See 
Horn. 

TOUCHSTONE.— The  black  basaltes 
is  used  for  examining  the  precious  metals 
by  the  touch,  and  is  commonly  distin- 
guished by  this  name.    See  Assay. 

The  touchstone,  as  described  by  some 
mineralogists,  is  a  sub-species  or  variety 
of  flint-slate.  It  is  called  also  Lydian 
stone.  The  mode  of  trying  metal,  as 
gold  or  silver,  by  the  ancients  with  this 
stone,  is  different  from  the  moderns.  The 
former  drew  the  metal  to  be  examined  on 
the  stone,  and  judged  of  the  purity  by  the 
colour  of  the  metallic  streak;  but  the 
latter,  after  drawing  the  metal  on  the 
stone,  ascertain  its  quality,  or  purity,  by 
the  agency  of  acids,  such  as  aqua  fortis, 
which  has  no  effect  on  pure  gold,  if  it  be 
that  metal  which  is  examined.  To  ascer- 
tain the  probable  quantity  of  alloy  in  a 
specimen,  a  number  of  needles  are  obtain- 
ed, which  contain  various  known  propor- 
tions of  alloy,  which,  when  rubbed  on  the 
stone,  and  examined  in  the  same  manner, 
will  give  a  probable  idea  of  the  compara- 
tive purity,  quality,  and  consequently  va- 
lue. This  stone  was  called  "  the  trier," 
from  this  circumstance ;  and  the  Lydian 
stone,  according  to  Theophrastus,  from 
its  being  found  most  abundantly  in  the  ri- 
ver Timolus  in  Lydia- 


TOUCHWOOD,  or  Spunk,  Boletus  ig< 
niarius,  L.  a  species  of  fungus,  or  sponge, 
which  grows  on  the  trunks,  particularly 
those  of  cherry  or  plum-trees  ;  where  it 
frequently  extends  to  a  size  of  from  two 
to  eight  inches. 

The  substance  of  this  vegetable  is  ve- 
ry hard  and  tough,  of  a  tawny-brown  co- 
lour, and  is  sometimes  employed,  both  in 
England  and  in  Germany,  as  a  substitute 
for  tinder :  with  this  design,  it  is  boiled  in 
a  strong  ley,  or  urine,  after  which  it  is 
dried,  and  boiled  a  second  time  in  a  solu- 
tion cf  saltpetre. 

TRAGACANTH  (Gum).— This  sub, 
stance,  which  is  vulgarly  called  gum  dra- 
gon, exudes  from  a  prickly  bush,  the  as- 
tragalus tragacanth  3,  Lin.  which  grows 
w  ild  in  the  warmer  climates,  and  endures 
the  cold  of  our  own,  but  does  not  here 
yield  any  gum.  This  commodity  is 
brought  chiefly  from  Turkey,  in  irregular 
lumps,  or  long  vermicular  pieces  bent  in- 
to a  variety  of  shapes ;  the  best  sort  is 
white,  semi-transparent,  dry,  yet  some- 
what soft  to  the  touch. 

Gum  tragacanth  differs  from  all  the 
other  known  gums,  in  giving  a  thick  con- 
sistence to  a  much  larger  quantity  of  wa- 
ter ;  and  in  being  much  more  difficultly 
soluble,  or  rather  dissolving  only  imper- 
fectly. Put  into  water,  it  slowly  imbibes 
a  great  quantity  of  the  liquid,  swells  into 
a  large  volume,  and  forms  a  soft  but  not 
fluid  mucilage  :  if  more  water  be  added, 
a  fluid  solution  may  be  obtained  by  agita- 
tion ;  but  the  liquor  looks  turbid  and 
wheyish,  and  on  standing  the  mucilage 
subsides,  the  limpid  water  on  the  surface, 
retaining  little  of  the  gum.  Nor  does  the 
admixture  of  the  preceding  more  solu- 
ble gums  promote  its  union  with  the  wa- 
ter, or  render  its  dissolution  more  dura- 
ble :  when  gum  tragacanth  and  gum  ara- 
ble are  dissolved  together  in  water,  the 
tragacanth  seems  to  separate  from  the 
mixture  more  speedily  than  when  dissolv- 
ed by  itself. 

TRAIN-OIL,  is  a  general  name  for  dif- 
ferent sorts  of  fish  oils ;  such  as  whale, 
seal,  cod,  elephant,  pilchard  oil,  £cc. 
Among  these,  whale  oil  is  by  far  the  most 
important  article. 

In  the  Greenland  whale  fishery,  when 
the  fat  is  all  got  off  from  the  whale,  it  is 
cut  in  small  pieces,  and  put  up  in  tubs  in 
the  hold,  cramming  them  very  full  and 
close ;  and  when  the  ships  get  home,  this 
fat  is  boiled  and  melted  down  into  train 
oil.  In  the  south  sea  fishery,  the  fat  is 
boiled  on  board  the  ships,  as  the  fish  are 
caught. 

Greenland  oil  is  purer  than  southern 

oil,  and  fit  for  different  purposes  where 


TUA 


TRO 


the  latter  will  not  answer;  it  is  on  that 
account  generally  worth  four  and  five 
pounds  per  ton  more 

The  seal  is  a  native  of  the  north  seas ; 
it  is  an  amphibious  animal  with  four  feet, 
and  called  in  many  places  the  sea-calf,  or 
sea-wolf.  Its  fat,  which  is  near  four  inches 
thick,  is  converted  into  train  oil,  and  the 
train  winch  drops  from  that  blubber,  is 
not  more  rancid,  than  stale  oil  of  olives. 

Train-oil  is  used  by  leather-dressers, 
soap-boilers ;  for  burning1,  8cc. 

TRANSPARENCIES,  painting  of— 
The  effect  of  this  kind"  of  painting,  which 
has  lately  become  very  fashionable,  though 
by  no  means  a  modern  invention,  is  very 
pleasing,  if  managed  with  judgment,  par- 
ticularly in  fire  and  moon-light  scenes, 
where  brilliancy  of  light  and  strength  of 
shade  are  so  very  desirable. 

The  very  great  expense  attending  the 
purchase  of  stained  glass,  and  the  risk 
of  keeping  it  secure  from  accident,  al- 
most precludes  the  use  of  it  in  ornament- 
ing rooms ;  but  transparencies  form  a 
substitute  nearly  equal,  and  at  a  very  small 
expense. 

The  paper  upon  which  you  intend  to 
paint  must  be  fixed  in  a  straining-frame, 
in  order  that  you  may  be  able  to  place  it 
between  you  and  the  light,  when  you  see 
occasion  in  the  progress  of  your  work. 
After  tracing  in  your  design,  the  colours 
must  be  laid  on  in  the  usual  method  of 
stained  drawings.  When  the  tints  are  got 
in,  you  must  place  your  picture  against 
the  window,  on  a  pane  of  glass  framed 
for  the  purpose,  and  begin  to  strengthen 
the  shadows  with  Indian-ink,  or  with  co- 
lours, according  as  the  effect  requires, 
laying  the  colours  sometimes  on  both 
sides  of  the  paper,  to  give  greater  force 
and  depth  of  colour.  The  last  touches  I 
for  giving  final  strength  to  shadows  and  [ 
forms,  are  to  be  done  with  ivory-black,  or  '. 
lamp-black,  prepared  with  gum-water,  as  ; 
there  is  no  pigment  so  opake  and  capa- 
ble of  giving  strength  and  decision. 

When  the  picture  is  finished,  and  eve- 1 
ry  part  has  got  its  depth  of  colour  and 
brilliancy,  being  perfectly  dry,  you  touch  ; 
very  carefully  with  spirits  of  turpentine 
on  both  sides,  those  parts  which  are  to  be 
the  brightest,  such  as  the  moon  and  fire, 
and  those  parts  requiring  less  brightness,  j 
only  on  one  side.    Then  lay  on  immedi- 
ately with  a  pencil,  a  varnish  made  by 
dissolving  one  ounce  of  Canada  balsam  in 
an  equal  quantity  of  spirit  of  turpentine. 
You  must  be  cautious  with  the  varnish, 
as  it  is  apt  to  spread.    When  the  varnish 
is  dry,  you  tint  the  flame  with  red-lead 
and  gamboge,  slightly  tinging  the  smoke 

VOL,  II. 


next  the  flame :  the  moon  must  not  be 
tinted  with  colour. 

Much  depends  upon  the  choice  of  the 
subject,  and  none  is  so  admirably  adapted 
to  this  species  of  effect  as  the  gloomy 
gothic  ruin,  whose  antique  towers  ani 
pointed  turrets  finely  contrast  their  dark 
battlements  with  the  pale  yet  brilliant 
moon.  The  effect  of  rays  passing  through 
the  ruined  windows,  half  choaked  with 
ivy,  or  of  a  fire  amongst  the  clustering 
pillars  and  broken  monuments  of  the 
choir,  round  which  are  figures  of  bandit- 
ti ;  or  others  whose  haggard  faces  catch 
the  reflecting  light :  these  afford  a  peculi- 
arity of  effect,  not  to  be  equalled  in  any 
other  species  of  painting.  Internal  views 
of  cathedrals,  also,  where  windows  of 
stained  glass  are  introduced,  have  a  beau- 
tiful effect. 

The  great  point  to  be  attained,  is  a  hap- 
py coincidence  between  the  subject  and 
the  effect  produced.  The  fire  light  should 
not  be  too  near  the  moon,  as  its  glare 
would  tend  to  injure  her  pale  silver  light ; 
those  parts  which  are  not  interesting 
should  be  kept  in  an  undistinguishable 
gloom,  and  where  the  principal  light  is, 
they  should  be  marked  with  precision. 
Groups  of  figures  should  be  well  contrast- 
ed ;  those  in  shadow,  crossing  those  that 
are  in  light,  by  which  means  the  opposi- 
tion of  light  against  shade  is  effected. 

TRIPOLI. — An  earth,  used  for  the  po- 
lishing of  metals,  &c.  similar  to  the  rot- 
ten-stone. It  was  originally  brought  from 
Tripoli,  whence  its  name ;  but  it  is  now 
found  in  other  countries  besides  Barbary. 

TRITURATION,  is  an  operation  of 
grinding,  performed  in  mortars,  on  por- 
phyries, and  in  mills. 

TROMPE, — The  trompe,  or  blowing 
machine,  is  formed  of  a  hollow  tree  which 
rests  upon  a  cask  whose  lower  head  is 
knocked  out,  and  the  open  part  of  the 
cask  itself  plunged  to  a  certain  depth  un- 
der water.  A  current  of  water  is  made 
to  fall  through  this  wooden  trunk  upon  a 
stone  which  is  erected  in  the  middle  of 
the  cask.  The  air  becomes  disengaged, 
and  is  obliged  to  pass  out  at  a  collateral 
aperture  in  the  cask,  by  means  of  a  tube 
which  carries  it  to  the  lower  part  of  the 
furnace.  This  air  is  afforded,  1.  by  that 
air  which  the  water  carries  along  with  it : 
2.  by  a  current  which  passes  through 
apertures  made  at  the  distance  of  six  feet 
from  the  summit  of  a  tree,  and  called 
trompilles.  We  use  the  French  names, 
because  we  do  not  know  of  any  appropri- 
ated English  terms. 

The  dimensions  of  a  good  trompe,  ac- 
cording to  Chaptal,  are  the  following : 

3  o. 


TRO 


TRO 


Length  of  tbe  tree,  or  wooden  trunk, 
from  its  summit  to  the  side  apertures  or 
trompilles,  six  feet. 

Length  of  the  tree,  from  the  trompilles 
to  the  cask,  eight  feet. 

Height  of  the  cask,  five  feet. 

Diameter  of  the  cask,  four  feet  six 
inches. 

The  form  of  the  internal  part  of  the 
trunk,  ahove  the  trompilles,  is  that  of  a 
funnel,  whose  superior  opening  is  eigh- 
teen inches,  and  its  inferior  diameter  five. 

The  diameter  of  the  cavity  of  the  tree, 
below  the  trompilles,  is  eighteen  inches. 

The  diameter  of  the  trompilles  is  six 
inches. 

Dr.  Lewis,  in  his  Philosophical  Com- 
merce of  Arts,  treats  expressly  on  this 
simple  and  useful  instrument,  on  which  he 
made  many  experiments.  The  following 
remarks,  references,  and  investigations, 
are  abridged  from  his  work. 

The  earliest  method  of  animating  the 
large  fires  of  the  furnace9  for  smelting 
ores,  appears  to  have  been  by  exposing 
them  to  the  wind.  Such  was  the  practice 
of  the  Peruvians  before  the  arrival  of  the 
Spaniards  in  that  country.  Alonso  Barba 
relates,  that  their  furnace,  called  guairas, 
were  built  on  eminences,  where  the  air 
was  freest ;  that  they  were  perforated 
on  all  sides  with  holes,  through  Which 
the  air  was  driven  when  the  wind  blew, 
which  was  the  only  time  the  work  could 
be  carried  on  ;  thajt  under  each  hole  was 
made  a  projection  of  the  stone  work  on 
the  outside,  and  that  on  these  projections 
were  laid  burning  coals  to  heat  the  air  be- 
fore its  entrance  into  the  furnace.  Some 
authors  speak  of  several  thousands  of 
these  guairas  burning  at  once  on  the  sides 
and  tops  of  the  hills  of  Potosi. 

It  is  said  that  several  remains  of  a  like 
rude  process,  are  to  be  seen  in  some  parts 
of  our  own  country.  The  old  bl  ornery 
hearths,  as  they  are  called,  for  the  running 
down  of  iron  ore,  are  all  on  the  tops  of 
hills ;  a  situation  which  can  scarcely  be 
supposed  to  have  been  chosen  on  any 
other  account  than  for  the  conveniency  of 
the  wind,  being  in  other  respects  extreme- 
ly incommodious. 

The  gradual  succession  of  bellows  to 
this  insufficient  mode  of  supplying  air, 
cannot  perhaps  be  traced.  It  appears, 
that  at  some  of  cur  iron -furnaces,  and 
others,  the  befiows  were  formerly  moved 
by  a  handle,  as  those  of  the  smith's  forge, 
or  by  the  pressure  of  the  foot  upon  a 
treadle,  or  by  other  means  requiring  the 
strength  of  men;  and  that  since  the  force 
of  water  has  been  called  in  aid  to  move 
them,  the  quantity  of  ore  run  down  has 


not  only  been  far  greater,  but  the  separa- 
tion of  the  metal  more  complete. 

The  first  account  that  is  to  be  met  with 
of  a  machine  for  propelling  air  into  fur- 
naces, by  a  fall  of  water  carrying  down 
air  with  it,  is  of  one  at  the  copper  or 
brass  furnaces  at  Tivoli,  near  Rome.  In 
this  machine  a  square  wooden  pipe  of 
considerable  width,  and  open  at  both 
ends,  is  placed  upright.  A  stream  of  wa- 
ter runs  in  at  the  top,  and  is  discharged 
at  the  bottom  :  and  about  the  middle  of 
the  height  of  the  pipe  a  smaller  horizon- 
tal one  is  inserted,  which  reaches  to  the 
furnace,  and  is  said  to  convey  to  it  a 
strong  blast  of  air. 

According  to  Mr.  Belidor,  a  pipe  with 
air  holes,  inserted  into  an  air  vessel,  is 
used  for  this  purpose  in  some  parts  of 
France. 

Mr.  Mariotte  gives  an  account  of  a  con- 
trivance for  blowing  fire  by  a  fall  of  wa- 
ter, which  consists  of  a  funnel  and  pipe, 
without  air  holes,  inserted  into  an  air  ves- 
sel. 

Mr.  Stirling  describes  a  machine  erect- 
ed in  Scotland,  for  blowing  air  ;nto  the 
furnace  in  which  lead  ores  are  smelted, 
and  for  conveying  fresh  air  into  the  works. 
This  machine  consists  of  a  funnel  and 
pipe,  with  air  holes,  inserted  into  an  air 
vessel- 

The  blowing  machines  used  in  Dauphi- 
ny,  for  the  forges  and  smelting  furnaces, 
have  a  great  resemblance  in  their  gene- 
ral structure  to  the  foregoing. 

In  the  county  of  Foix,  the  blowing  ma- 
chines, as  described  by  Reaumur,  are 
considerably  different  from  the  foregoing. 
The  pipe  is  rectangular,  and  the  part 
above  the  choak  divides  into  three  funnel- 
shaped  partitions.  On  the  top  is  a  reser- 
voir or  cistern  of  water :  and  two  of  the 
partitions,  close  on  all  sides,  pass  up 
above  the  surface  of  the  water,  for  carry- 
ing down  air,  and  thus  supplying  the 
place  of  the  lateral  air  holes  :  the  water 
enters  into  the  third  partition,  which  is 
only  the  space  between  the  two  forego- 
ing, and  which  has  but  two  sides,  formed 
by  the  two  opposite  sides  of  the  others. 

Mr.  Barthes  gives  a  minute  descrip- 
tion of  a  blowing  machine  at  the  forge  of 
St.  Pierre,  on  the  river  Obriou.  Its  gene- 
ral structure  is  nearly  the  same  with  that 
of  Foix,  but  the  height  of  water  above 
the  choak  much  less. 

Dr.  Lewis's  trials,  though  not  carried 
to  such  a  length  as  he  could  have  wish- 
ed, satisfied  him  and  those  who  assisted 
at  them,  that  much  more  air  is  to  be  ob- 
tained by  dividing  the  stream  by  means 
of  a  cullender,  than  by  any  other  me- 


TRO 

thods  that  have  been  tried ;  and  that  with 
such  a  machine  as  that  of  St.  Pierre 
above  described,  a  stream  of  a  hundred 
and  fifty  gallons  at  most  in  a  minute  is 
sufficient  to  produce  a  continued  blast 
from  a  pipe  of  three  quarters  of  an  inch 
bore,  of  such  strength  as  to  support  a  co- 
lumn of  water  of  three  feet  or  more. 

His  summary  view  of  the  most  mate- 
rial particulars  which  his  experiments 
have  discovered,  with  regard  to  the  per- 
fection of  the  structure  of  blowing  ma- 
chines, and  his  description  from  them  of 
such  a  machine  as  promises  to  be  the 
most  effectual,  are  as  follow  : 

The  bottom  of  the  reservoir  of  the  wa- 
ter should  be  about  fourteen  feet  above 
the  level  of  the  ground :  we  need  not  be 
very  solicitous  about  procuring  a  greater 
height ;  for  though  a  greater,  would  be  of 
some  advantage,  yet  this  advantage  ap- 
pears to  be  much  less  considerable  than 
has  been  commonly  imagined.  In  the 
channel  by  which  the  water  is  conveyed, 
are  to  be  placed  gratings  of  different 
sizes ;  and  before  the  aperture  a  finer 
grating,  which  may  be  either  a  perforat- 
ed iron  plate  or  a  wire  sieve,  to  serve  as 
strainers  for  keeping  back  such  matters 
as  would  obstruct  the  apertures  which 
the  water  is  afterward  to  pass  through. 
The  stream  should  enter  at  one  side,  or 
be  so  managed,  that  the  water  in  the  re- 
servoir or  funnel  may  not  be  agitated  by 
it,  or  put  into  a  spiral  motion,  which  Dr. 
Lewis's  experiments  showed  to  be  very  in- 
jurious. 

In  the  bottom  of  the  reservoir  is  to  be 
made  a  round  hole,  for  admitting  the  up- 
per end  of  a  cylindrical  pipe  of  copper  or 
cast  iron,  five  or  six  inches  in  the  bore, 
and  seven  feet  long.  To  the  end  of  this 
pipe  is  to  be  fitted  a  cullender  about  a  foot 
long,  with  the  holes  triangular,  of  half  an 
inch  each  side ;  and  six  or  seven  spaces 
from  top  to  bottom,  at  equal  distances, 
must  be  left  without  holes,  for  admitting 
air  to  pass  down  to  the  lower  streams. 
All  the  holes  should  be  directed  down- 
wards, that  the  streams  may  not  be  forci- 
bly projected  against  the  sides  of  the 
pipe  which  is  to  receive  them,  so  as  to 
have  their  velocity  too  much  diminished. 

If  there  are  six  of  the  perforated  spaces 
in  the  cullender,  the  number  of  holes  in 
each  may  be  twenty ;  so  that  the  whole 
number  will  be  one  hundred  and  twenty. 
The  side  of  each  of  the  triangular  holes 
being  half  an  inch,  the  area  of  each  will 
be  the  eighth  part  of  a  square  inch,  and 
the  sum  of  their  areas  will  be  fifteen 
square  inches.  The  quantity  of  water 
running  through  one  aperture  of  such  an 


TRO 

area,  at  the  depth  of  seven  feet  and  a  half 
under  the  surface,  comes  out  on  calcula- 
tion about  six  hundred  and  twenty-two 
gallons  in  a  minute ;  but  the  real  quanti- 
ty will  doubtless  be  much  less  than  this, 
on  account  of  the  great  friction  of  the 
water  in  passing  through  a  number  of 
small  holes,  and  of  the  resistance  of  the 
air,  which  increases  in  a  very  high  ratio 
according  to  the  increase  of  the  velocity 
and  enlargement  of  the  surface:  it  is  in 
part  to  make  up  for  these  retardations, 
that  the  pipe  is  directed  to  be  made  so 
high.  The  surface  of  the  water  is  here 
above  thirteen  times  greater  than  if  it 
passed  all  through  one  circular  aperture. 

Both  the  pipe  and  the  cullender  should 
have  a  flanch  or  rim  round  their  orifices, 
and  be  secured  to  one  another  by  screws 
passing  through  the  rims  of  both,  with  a 
plate  of  lead  between  them  to  make  the 
juncture  tight,  as  commonly  practised  in 
joining  iron  pipes  for  water  works.  This 
way  of  joining  them  admits  the  cullender 
to  be  taken  off  and  cleaned,  when  a  dimi- 
nution of  the  effect  of  the  machine  shows 
the  holes  to  be  choked  up  ;  which,  howe- 
ver, it  is  apprehended,  will  seldom  if  ever 
happen. 

As  the  holes  will  permit  more  water  to 
run  through,  than  may  at  all  times  be 
wanted,  it  is  proper  to  have  some  contri- 
vance for  occasionally  closing  a  part  of 
them.  This  may  be  effected  by  means  of 
a  thin  copper  pipe,  open  at  both  ends,  as 
high  as  the  cullender,  and  of  such  width 
as  just  to  drop  into  it.  It  will  be  easily 
conceived,  that  when  this  register  is  let 
entirely  down,  the  lateral  holes  will  be 
covered,  and  the  water  admitted  only  to 
those  in  the  bottom ;  and  that  by  raising 
it  farther  and  farther,  more  and  more  of 
the  lateral  holes  will  be  uncovered.  The 
register  is  to  be  hung  by  a  wire  to  a  cross- 
bar over  the  reservoir,  by  which  it  may 
be  raised  or  lowered ;  and  a  scale  or  di- 
vided board  may  be  adjusted  against  the 
upper  part  of  the  wire,  for  showing  the 
height  of  the  register,  or  the  number  of 
holes  closed  by  it. 

The  most  commodious  and  effectual 
way  of  admitting  air  to  the  water  appears 
to  be  that  of  hanging  the  throat  of  the 
funnel,  in  this  case  the  cullender,  within 
the  wider  receiving  pipe;  for  by  this 
means  the  air  is  admitted  freely  and  uni- 
formly all  round.  This  last  pipe  should 
likewise  be  of  iron  or  copper,  twelve 
inches  in  diameter,  and  spread  out  at 
top  to  the  width  of  sixteen  or  eighteen 
inches,  that  a  large  space  may  be  kit 
round  the  cullender :  this  space  should 
reach  three  or  four  inches  above  the  up- 


_  TRO 

permost  perforations  of  the  cullender,  to 
prevent  any  of  the  water  from  being  dash- 
ed over  the  top. 

A  pit  is  to  be  sunk  in  the  ground,  not 
less  than  six  feet  deep.  In  this  is  to  be 
placed  an  air  vessel,  made  of  wood  lined 
with  lead,  without  a  bottom,  three  or  four 
feet  in  width,  and  ten  or  eleven  high.  The 
vessel  should  be  supported  on  feet  of  a 
proper  strength,  with  sufficient  spaces  be- 
tween them  for  the  water  to  pass  freely 
out :  tliis  way  is  preferable  to  the  com- 
mon one  of  placing- the  lower  edge  of  the 
vessel  on  the  bottom  of  the  pit,  and  cut- 
ting- an  aperture  in  the  side,  because  the 
heig-ht  of  the  aperture  is  so  much  taken 
off*  from  that  of  the  vessel  The  reser- 
voir  being  fourteen  feet  above  the  ground, 
and  the  upper  pipe  and  cullender  reach- 
ing down  eight  feet,  only  six  feet  remain 
below  the  cullender;  so  that  the  air  ves- 
sel having  six  feet  sunk,  the  ground  will 
reach  nearly  up  to  the  cullender,  and  al- 
most the  whole  height  of  the  undermost 
pipe  will  be  included  within  the  vessel. 
This  pipe  may  be  above  nine  feet  long, 
three  feet  or  more  of  it  going  down  into 
the  pit ;  which  three  feet  are  here  an  en- 
tire gain  in  the  height  of  the  fall,  for  the 
pipe  in  the  other  machines  comes  at  most 
no  lower  than  the  level  of  the  ground 
where  the  water  runs  off  on  the  outside. 
This  height  is  gained  in  virtue  of  the  com- 
pressed air  in  the  vessel  pushing  down 
the  water  below  :  it  may  be  always  as 
great  as  the  height  to  which  the  water  is 
intended  to  rise  in  the  guage.  At  the  dis- 
tance of  five  or  six  inches  under  the  ori- 
fice of  the  pipe  is  to  be  placed  the  con- 
cave iron  plate  or  stone  for  the  water  to 
fall  on.  In  the  top  of  the  air  vessel  is  to 
be  fixed  the  guage  and  the  blowing  pipe. 

Such  is  the  general  construction  of  the 
blowing  machine,,  which  (says  Dr.  Lewis) 
promises  to  be  particularly  useful  in  cases 
where  water  is  scarce,  or  where  the  want 
of  a  natural  fall  renders  it  necessary  to 
raise,  by  very  expensive  means,  the  great 
quantities  requisite  for  working  the  com- 
mon bedovvs.  Dr.  Lewis  thinks  too,  that 
one  of  these  machines  will  be  sufficient 
for  the  iron  forge,  and  for  sundry  other 
purposes  where  the  quantity  of  air  is  not 
required  to  be  very  great ;  that  it  will  be 
less  expensive,  on  account  of  the  durabi- 
lity of  its  materials  and  the  simplicity  of 
its  structure,  than  any  kind  of  bellows 
now  in  use  ;  and  what  is  of  principal  im- 
portance, that  much  less  water  will  serve 
for  working  it.  He  adds,  in  cases  where 
one  of  the  machines  cannot  supply  air 
enough,  as  for  the  large  iron  smelting 
furnace,  two  pipes  may  be  used,  both  fed 
by  one  reservoir,  and  entering  into  one  air 


TRO 

vessel.  The  using  of  two  pipes  appears 
more  eligible  than  enlarging  the  bore  of 
one  ;  for  air  cannot  be  so  freely  introduced 
into  a  large  body  of  water,  though  divided 
into  streams  by  "the  cullender,  as  into  two 
smaller  ones  of  equal  quantity. 

It  may  be  observed,  that  the  blast  will 
be  stronger  in  a  dense  state  of  the  atmos- 
phere, than  when  it  is  more  rare  or  ex- 
panded, a  greater  quantity  of  air  being 
then  introduced  under  an  equal  volume. 
If,  therefore,  the  quantity  of  water  has 
been  adjusted  so  as  to  raise  the  guage  to 
a  proper  height  when  the  air  was  light,  it 
will  frequently  happen,  that  the  same 
quantity  of  water  shall  raise  it  higher,  and 
consequently,  if  no  greater  height  is  re- 
quired, that  a  part  of  the  water  may  be 
saved.  As  the  guage  of  the  machine  dis- 
covers by  inspection  the  variations  in  its 
effect,  the  register  affords  convenient 
means  of  regulating  its  power,  and  in- 
creasing or  diminishing  the  quantity  of 
water. 

The  method  of  blowing  in  our  large 
furnaces  is  by  iron  bellows  or  machines, 
worked  by  a  steam  engine.  Some  years 
ago  1  had  a  conversation  on  this  subject 
with  one  of  our  most  eminent  iron  mas- 
ters, whose  name  I  should  be  glad  to 
mention  as  a  credit  to  m}  self,  if  1  had  at 
this  time  an  opportunity  of  asking  his  per- 
mission. 

The  air  machines  are  iron  cylinders  six 
feet  in  diameter,  in  which  a  piston  works 
with  a  stroke  of  seven  feet  in  length. 
Each  stroke,  therefore,  intrudes  198  cu- 
bic feet  of  air.  At  best  the  rate  of  work- 
ing is  sixteen  strokes  in  a  minute.  The 
density  of  the  air  is  such  that  it  will  raise 
three  pounds  weight  on  a  square  inch 
hole  in  the  piston,  in  which  effect  the 
stroke  lias  some  part.  For  the  pressure 
in  the  reservoir  is  less,  being  about  two 
pounds  on  the  same  surface.  The  reser- 
voir, called  the  regulating  belly,  is  a  large 
close  chamber  open  below,  and  surround- 
ed with  a  sufficient  mass  of  water  to  rise 
within  it,  and  by  its  reaction  keep  up  the 
density  of  the  air  with  which  its  upper 
part  is  supplied  from  the  cylinder.  The 
differences  of  height  between  the  surfaces 
of  the  water  within  and  without  the  re- 
servoir is  between  six  and  seven  feet,  and 
the  rise  and  fall  at  each  stroke  of  the  pis- 
ton is  about  four  or  five  inches  on  the 
outer  surface.  1  think  he  afterward  said 
two  or  three.  From  this  last  datum  we 
may  deduce  the  size  of  the  regulating 
belly  or  its  horizontal  section.  For  its 
surface  will  be,  to  that  of  the  piston,  in- 
versely as  this  rise  is  to  the  length  of  the 
stroke.  If  the  medium  of  the  first  num- 
bers be  taken,  its  surface  will  be  19  times 


THO 


TUN 


that  of  the  piston,  which  is  28\  square 
feet,  that  is  to  say,  536  square  feet,  or  a 
square  whose  side  is  23  feet.  But  if  the 
medium  of  the  second  numbers  be  taken, 
the  surface  will  be  45  times  that  of  the 
piston,  tliat  is  1271  square  feet,or  a  square 
whose  side  is  about  36  £  feet.  The  larger 
this  surface,  the  steadier  the  blast.  From 
the  regulating  belly  proceeds  the  nozzle, 
or  twycr,  (tuyere)  as  it  is  called.  Its  dia- 
meter at  the  aperture  is  one,  two  or  three 
inches.  They  have  sometimes  enlarged 
them  for  experiment  as  tar  as  five  ;  but 
they  then  found  the  apparatus  not  to  sup- 
ply the  air  quickly  enough,  or  at  least  not 
with  the  same  advantage  as  when  a 
smaller  aperture  was  used.  « 

If  we  attend  to  the  height  of  the  water 
on  the  outside  of  the  reservoir,  we  shall 
find  the  force  of  this  apparatus  to  be 
greatly  beyond  that  of  the  other  bellows 
in  use.  Six  or  seven  feet  of  water  upon 
the  base  of  a  square  inch  will  give  72  or 
84  solid  inches,  and  those  at  a  thousand 
ounces  to  the  cubic  foot,  or  1728  inches, 
will  give  41  ounces,  or  two  pounds  nine 
ounces  for  the  pressure  upon  a  square 
inch,  represented  by  the  first  of  these 
numbers.  The  second  number  will  give 
near  48  ounces,  or  three  pounds.  These 
pressures  referred  to  a  column  of  mercu- 
ry, which  is  a  very  usual  and  convenient 
method  of  admeasurement,  will  corres- 
pond to  5.3  and  6.2  inches  elevation  of 
that  fluid  ;  that  is  to  sayj  at  most  not  one- 
fifth  of  an  atmosphere. 

In  some  of  the  early  volumes  of  the 
Abridgment  of  the  Transactions,  there  is 
an  account  of  a  method  of  conveying  air 
to  vast  distances,  through  pipes  for  the 
purpose  of  blowing,  and  as  1  think,  speak- 
ing from  recollection,  for  the  communica- 
tion of  mechanic  effect.  This  scheme  was 
put  in  practice  by  the  father  of  the  iron- 
master from  whom  the  preceding  infor- 
mation was  received.  The  project,  which 
did  not  succeed,  cost  four  thousand 
pounds.  Three  engines  were  erected,  con- 
sisting of  bellows  worked  by  large  water 
wheels,  at  a  fall  of  water  eighteen  hun- 
dred yards  distant  from  the  iron  work  to 
which  the  air  was  intended  to  be  convey- 
ed. A  pipe,  ten  inches  diameter,  convey- 
ed the  air  from  the  engine  to  the  works, 
and  the  stream  of  air  was  never  so  strong 
as  to  blow  out  a  candle.  So  1  find  it  in 
my  notes ;  but  I  think,  from  recollection, 
the  expression  was  to  affect  the  flame  of  a 
candle,  and  certainly  a  very  gentle  breath 
of  air  was  meant.  The  engine  worked 
but  a  few  strokes  before  it  stopped.  The 
proprietor  concluded,  that  the  pipe  was 
in  some  part  designedly  obstructed  ;  but 
upon  advice,  he  put  a  cat  into  the  pipe, 


which  -walked  through  it  and  came  out  at 
the  other  end. 

It  remained,  therefore,  to  ascertain 
whether  the  obstruction  of  the  air  arose 
merely  from  the  length  of  the  pipe  For 
this  purpose  holes  were  cut  in  the  pipe  at 
various  distances  from  the  end  at  which 
the  air  entered  and  proper  coverings  pre- 
pared, that  each  might  be  opened  at  plea- 
sure. It  was  found,  that  the  engine  work- 
ed slower,  the  remoter  the  hole  which 
was  opened,  the  wind  issuing  of  course 
with  less  strength ;  and  when  the  hole 
was  made  at  a  certain  distance,  it  stop- 
ped. 1  did  not  ask  the  distance.  It  is 
said,  that  the  passage  of  air  from  a  blow- 
ing machine  to  its  place  of  escape  is  con- 
siderably impeded  through  pipes  of  the 
length  of  40  or  50  feet.  The  fact,  which 
is  perfectly  authentic,  is  certainly  very  cu- 
rious. Whether  it  is  to  be  ascribed,  to 
the  loss  by  friction  of  a  momentum,  in 
which  the  velocity  is  so  great  and  the 
mass  so  small,  or  whether  there  be  any 
effect  similar  to  that  stickage  which  takes 
place  when  wool,  or  other  elastic  bodies 
are  rammed  into  a  tube,  must  be  deter- 
mined from  a  numerical  estimate  of  all 
the  facts,  and  may  perhaps  require  new 
experiments.  I  cannot  help,  however, 
entertaining  the  opinion,  that  the  former 
cause  is  the  most  effectual  in  this  busi- 
ness ;  and  that  the  undertaking  here  de- 
scribed might  have  been  made  to  answer, 
by  enlarging  the  diameter  of  the  tube. 
For  if  the  impediment  be  friction  arising 
from  the  velocity  of  the  mass,  that  element 
will  diminish  in  proportion  as  the  diame- 
ter of  the  tube  is  increased,  and  the  quan- 
tity of  surface  rubbed  against  by  the  same 
mass  of  air  will  not  alter.  Hence  it  slrould 
follow,  that  if  a  tube,  of  an  inch  diameter 
and  three  feet  long,  do  not  perceptibly  re- 
sist the  passage  of  the  air,  another  tube, 
thirty  feet  long,  will  afford  no  more  re- 
sistance, provided  its  diameter  be  ten 
inches,  that  is  to  say,  proportional  to  its 
length: 

TRUNDLE.    See  Mechanics. 

TUNGSTEN". — Tungsten  is  obtained 
from  a  mineral  called  wolfram,  which 
contains  the  oxyds  of  tungsten,  manga- 
nese and  iron,  with  earthy  matter.  Mine- 
ralogists cail  tungsten  a  mineral,  which 
contains  the  oxyd  or  acid  combined  with 
lime.  Although  several  attempts  have 
been  made  by  different  chemists  to  obtain 
this  metal,  yet  very  few  have  succeeded. 
It  may  be  produced  in  the  following  man- 
ner, according  to  Reenter. 

Let  equal  parts  of  tungstic  acid  and 
dried  blood  be  exposed  for  some  time  to 
a  red  heat  in  a  crucible;  press  the  black 
powder  which  is  formed  into  another 


TUR 


TUR 


amaller  crucible,  and  expose  it  again  to  a 
violent  heat  in  a  forge  for  at  least  an  hour. 
Tungsten  will  then  be  found,  according 
to  this  chemist,  in  its  metallic  state  in  the 
crucible. 

To  produce  the  metal  pure,  the  follow- 
ing process  has  been  recommended. 

Boil  finely  pulverized  wolfram  in  strong 
muriatic  acid  for  some  time ;  separate  the 
solution  ;  the  residuum  contains  a  yellow 
powder;  it  is  to  be  washed,  dissolved  in 
ammonia,  evaporated  to  dryness,  and  mix- 
ed with  a  fine  charcolian  powder,  and  ex- 
posed to  a  very  intense  heat  for  about  20 
minutes  in  a  covered  Hessian  crucible  — • 
Small  grains  of  puie  tungsten  will  be 
found  at  the  bottom  of  the  crucible. 

Tungsten  in  its  metallic  form,  was  first 
procured  by  Messrs  D'Ethuryrs  in  1782. 

Tungsten,  or  Scheelium  of  the  Ger- 
mans, is  of  a  grayish  white  colour.  Its 
specific  gravity  is  17.3-  It  requires  for 
fusion  about  170°  Wedgwood.  It  com- 
bines with  oxygen,  forming  a  blue  and 
yellow  oxyd.  The  prot  oxyd  is  blue,  and 
the  per  oxyd  is  yellow,  "known  by  the 
name  of  tungstic  acid. 

TURF.    See  Peat. 

TURNSOLE.  See  Litmus  and  Dye- 
ing. 

TURKEY  STONE.  Cos  Turcica.  This 
.stone  is  of  a  dull  white  colour,  and  often 
of  an  uneven  texture,  some  parts  appear- 
ing more  compact  than  others,  so  that  it 
is  in  some  measure  shattery.  It  is  used 
as  a  whetsone  :  and  those  of  the  finest 
grain  are  the  best  hones,  for  the  most  de- 
licate cutting  tools,  and  even  for  razors, 
lancets,  &c.  Its  specific  gravity  is  2.598. 
It  gives  fire  with  steel,  yet  effervesces 
with  acids.  Kirwan  found,  that  luU  parts 
of  it  contain  25  of  carbonate  of  lime,  and 
no  iron. 

There  probably  are  two  sorts  of  stones 
known  by  this  name,  as  Wallerius  affirms, 
that  which  he  describes,  neither  to  give 
fire  with  steel,  nor  efiervesce  with  acids. 
Workmen  affirm,  that  this  stone  hardens 
with  oil.  The  value  of  such  specimens 
as  contain  a  very  fir.e  grit,  or  siliceous 
part,  is  much  greater  than  that  of  com- 
mon samples.  Artists  select  them  by 
trial;  but  it  is  not  generally  known,  that 
most  of  these  stones,  have  a  fine  and  a 
coarse  side,  and  ought  therefore  to  be 
sawed  with  an  attention  to  this  circum- 
stance. It  naturally  arises  from  the  stone 
having  been  formed  from  subsidence  in 
water. 

This  stone  is  found  in  several  places 
in  the  United  States,  equal  in  quality  to 
the  imported. 

TURKEY-RED.    See  Dyeing. 


TURKISH,  OR  ORIENTAL  PASTE. 

The  jewellers  of  Paris  have  of  late  years, 
formed  many  handsome  ornaments,  such 
as  ear-rings,  bracelets,  broaches,  made  of 
a  kind  of  stone  or  perfumed  paste.  On 
the  examination  of  this  mock  jewellery,  it 
has  been  found  to  be  made  from  the  Japan 
earth,  known  by  the  name  of  mimosa  ca- 
techu, an  article  well  known  in  the  materia 
medica,  and  being  mixed  with  musk  or 
ambergris,  to  render  it  perfumed,  and 
diluted  with  gum  dragant,  it  is  rendered 
into  the  requisite  form  by  proper  moulds, 
according  to  the  following  process  : 

They  first  take  the  requisite  quantity 
ot'eatechou,  reduced  into  small  bits,  on  this 
is  then  poured  eight  times  its  weight,  m 
equal  quantities  of  strong  water  and  vine- 
gar, and  rose  water ;  this  mixture  is  then 
put  into  a  glass-bottle,  stopped  with  a 
piece  of  moistened  bladder,  pierced  with 
a  pin-hole  to  give  access  to  the  air,  it  is 
then  placed  in  a  sand-bath,  or  on  a  stove 
moderately  heated,  until  the  catechou  is 
dissolved. 

Thus  dissolved  it  is  suffered  to  grow 
cool,  and  then  filtered  through  gray  pa- 
per ;  it  is  then  put  into  a  retort,  to  which 
is  attached  a  recipient.  The  whole  of 
the  spirit  is  then  distilled,  until  it  emits 
nothing  but  clear  water. 

The  residue  at  the  bottom  of  the  retort 
is  then  put  into  a  china  bowl,  and  to  every 
ounce  of  dissolved  catechou  is  then  add- 
ed half  a  drachm  of  the  solution  of  gum 
dragant,  and  the  whole  is  mixed  up  into 
a  thick  paste,  which  congeals  in  the  cold. 
Whilst  the  paste  remains  ductile,  there 
is  added  the  quantity  of  from  four  to  six 
grains  well  pulverized,  to  the  quantity  of 
every  half  ounce,  and  the  whole  is  to  be 
v.  t  li  mixed  up  together. 

This  preparation  of  the  paste  is  then 
put  into  the  requisite  shaped  moulds, 
made  of  either  copper  or  brass,  and  the 
inside  of  which  must  be  well  polished, 
and  anointed  with  oil  of  almonds  or  jessa- 
mine, to  prevent  the  paste  from  adhering 
thereto.  It  is  then  covered  over,  and  left 
to  harden  gradually. 

TURMERIC,  (terra  merita,)  curcuma 
longa,  is  a  root  broug'ht  to  us  from  the 
East  Indies.  Bei  thollet  had  an  opportu- 
nity of  examining  some  turmeric,  that 
came  from  Tobago,  which  was  superior 
to  that  which  is  met  with  in  commerce, 
both  in  the  size  of  the  roots,  and  the  abun- 
dance of  the  colouring  particles.  This  sub- 
stance is  very  rich  in  colour,and  there  is  no 
other  which  gives  a  yellow  colour  of  such 
brightness ;  but  it  possesses  no  durability, 
nor  can  mordants  give  it  a  sufficient  de- 
gree.  Common  salt  and  sal  ammoniac. 


Tin 


TUR 


are  those  whicb  fix  the  colour  best,  but 
they  render  it  deeper,  and  make  it  incline 
to  brown  ;  some  recommend  a  small 
quantity  of  muriatic  acid.  The  roots 
must  be  reduced  to  powder  to  be  fit  for 
use.  It  is  sometimes  employed  to  give 
the  yellows  made  with  weld  a  gold  cast, 
and  to  give  an  orange  tinge  to  scarlet ; 
but  the  shade  the  turmeric  imparts,  soon 
disappears  in  the  air. 

iMr.  Guhliche  gives  two  processes  for 
fixing  the  colour  of  turmeric  on  silk  — 
The  first  consists  in  aluming  in  the  cold 
for  12  hours,  a  pound  of  silk  in  a  solution 
of  two  ounces  of  alum,  and  dyeing  it  hot, 
but  without  boiling,  in  a  bath  composed 
of  two  ounces  of  turmeric,  and  a  quart 
(measure)  of  aceto-citric  acid,  mixed  with 
three  quarts  of  water.  The  second  pro- 
cess, consists  in  extracting  the  colouring 
particles  from  the  turmeric,  by  aceto-ci- 
tric  acid,  in  the  way  described  for  Brazil- 
wood,  and  in  dyeing  the  silk  sdumed,  .is 
already  mentioned  in  this  liquor,  either 
coid  or  moderately  warm.  The  colour 
is  rendered  more  durable  by  this,  than  by 
the  former  process. 

The  first  parcel  immersed,  acquires  a 
gold  yellow  ;  the  colour  of  the  second  and 
third  parcels,  is  lighter,  but  of  the  same 
kind  ;  that  of  the  fourth  is  a  straw  colour. 
Mr.  Guhliche  employs  the  same  process, 
to  extract  fine  and  durable  colours  from 
fustic,  broom,  and  French  berries  :  he  pre- 
pares the  wool  by  a  slight  aluming,  to 
which  he  adds  a  little  more  muriatic  acid. 
He  seems  to  content  himself  in  these  cases 
with  vinegar,  or  some  other  vegetable 
acid,  instead  of  his  aceto-citric  acid,  for 
the  extraction  of  the  colour ;  he  directs 
that  a  very  small  quantity  of  solution  of 
tin,  should  be  put  into  the  dye-bath. 

TURPENTINE,  and  other  resinous 
products  of  the  Pine. 

Under  this  head,  we  shall  describe  the 
methods  of  procuring  and  preparing  a  va- 
riety of  very  important  articles  of  com- 
merce, such  as  turpentine,  resin,  pitch, 
tar,  &c.  which  are  employed  so  extensive- 
ly in  ship-building  and  rigging,  in  var- 
nishes, and  many  other  purposes  of  infe- 
ferior  interest. 

AH  these  are  the  products  of  one  or 
other  species  of  pine,  and  sometimes  the 
same  substance  is  yielded  by  different 
species,  as  all  the  varieties  of  the  native 
resin,  or  turpentine,  have  a  very  great  re- 
semblance in  chemical  properties. 

There  are  three  varieties  of  pine  tur- 
pentine, commonly  known  under  that 
name  in  Europe. 

1.  The  common  turpentine,  obtained 
chiefly  from  the  Pir.us  Svlvestris  (Scotch 
Fir.) 


2.  The  Strasburgh  turpentine  yielded 
by  the  Pinus  Picea  (Silver  Fir.) 

3.  The  Venice  turpentine  procured  from 
the  Pinus  Larix  (Larch.)  To  these  may 
be  added  two  liquid  turpentines. 

4  The  Carpathian  or  Hungary  balsam, 
which  it  exsudes  from  the  Pinus  Cem- 
bra  (Siberian  Stone  Pine.) 

5.  The  Canada  balsam,  the  resinous 
juice  of  the  Pinns  Balsamea  (Balm  of 
Gilead  Fir.) 

The  fine  fragment  Chio  turpentine,  is 
not  procured  from  a  pine,  but  from  a  low 
shrub  (the  Pistacia  Lentiscus)  which  will 
be  described  in  the  next  article. 

Of  the  three  first-mentioned  turpentines, 
the  Venice  is  the  thinnest  and  most  aro- 
matic, the  Strasburg  the  next,  in  these 
qualities,  and  the  common,  is  the  firmest 
and  coarsest.  The  two  former  are  often 
adulterated  by  a  mixture  of  the  common 
turpentine,  and  oil  of  turpentine,  and  it  is 
to  be  observed,  that  the  terms  Venice  and 
Strasburg  turpentine,  are  not  now  appro- 
priate, as  they  are  procured  from  various 
countries. 

Common  turpentine  is  obtained  largely 
in  the  pine  forests,  in  the  south  of  France, 
in  Switzerland,  in  the  countries  on  the 
north  of  the  Pyrenees,  in  Germany,  and 
in  many  of  the  southern  states  of  North 
America.  The  greater  part  of  what 
is  consumed  in  Europe,  is  imported 
from  North  America.  The  method  of 
obtaining  it,  is  by  making  a  series  of  inci- 
sions through  the  bark  of  the  tree,  from 
winch  the  turpentine  exsudes,  and  falls 
down  into  holes,  or  other  receptacles  at 
the  foot.  The  process  is  described  very 
accurately  by  Duhamel  and  Moringlane, 
as  practised  in  the  south  of  France. 

The  fir  is  generally  allowed  to  remain 
untouched,  till  it  is  thirty  or  forty  years 
old.  When  it  is  to  be  worked,  which  is 
early  in  the  spring,  a  small  hole  is  first 
made  in  the  ground  at  the  foot  of  the  tree, 
the  earth  of  which  is  well  rammed,  and 
serves  as  a  receptacle  for  the  juice.  The 
coarse  bark  is  then  stripped  off  from  the 
tree,  a  little  above  the  hole  down  to  the 
smooth  inner  bark,  after  which  a  portion  of 
the  inner  bark  together  with  a  little  of  the 
wood,  is  cut  out  with  a  very  sharp  tool, 
so  that  there  may  be  a  wound  in  the  tree 
about  three  inches  square,  and  an  inch 
deep.  Immediately  afterwards,  the  tur- 
pentine begins  to  exsude  in  very  transpa- 
rent drops,  which  escape  chiefly  from  the 
wood,  immediately  under  the  inner  bark. 
The  hotter  the  weather  is,  the  greater  is 
the  supply  of  resin,  and  to  facilitate  the 
supply,  the  incisions  are  enlarged  every 
three  or  four  days,  by  cutting  off  thin 
slices, till  at  the  end  of  the)  ear,  it  is  about 


TUIi 


TUR 


a  loot  and  a  half  wide,  and  two  or  three 
inches  deep.  The  whole  time  during 
which  the  turpentine  flows,  is  from  the 
end  of  February  to  October.  In  the  win- 
ter it  entirely  ceases,  but  in  the  ensuing- 
spring',  a  fresh  incision  is  begun  a  little 
above  the  former,  and  managed  in  the 
same  manner.  This  practice  is  continued 
annually,  for  about  twelve  or  fifteen  years, 
in  some  parts,  and  in  others  a  shorter  time, 
on  the  same  side  of  the  tree,  till  the  latter 
incisions  are  so  high,  as  to  be  out  of  reach 
without  the  assistance  of  steps ;  after 
which  the  contrary  side  of  the  tree  is  be- 
gun upon,  and  worked  in  a  similar  man- 
ner for  as  many  years,  during  which  time 
the  first  incisions  are  grown  up,  and  are 
fit  to  be  cut  afresh.  In  this  way,  a  healthy- 
tree  in  a  favourable  soil,  may  be  made  to 
yield,  from  six  to  twelve  or  more  pounds 
of  turpentine  annually,  sometimes  for  a 
century,  and  even  the  timber  is  not  soon 
injured  by  this  constant  drain. 

The  flow  of  turpentine  discontinues  al- 
together about  October,  and  the  liquid  re- 
sin collected  during  the  year  from  each 
tree,  is  put  together  for  further  purifica- 
tion. But  a  considerable  quantity  of  the 
resin,  has  concreted  during  that  time 
around  the  incision,  particularly  as  the 
heat  declines  ;  and  in  the  winter  when  it 
has  hardened  considerably  it  is  scraped 
off,  and  forms  what  is  technically  called 
Barras,  or  in  some  provinces  Galipot, 
which  differs  from  the  more  liquid  tur- 
pentine in  consistence,  and  probably  con- 
tains a  less  proportion  of  essential  oil  — 
The  galipot  is  much  used  in  making  flam- 
beaux, when  mixed  with  suet,  but  the 
greater  part  of  it,  as  well  as  the  liquid 
turpentine,  is  subjected  to  further  pro- 
cesses. 

These  we  shall  resume  when  we  have 
described  the  method  of  obtaining  the 
other  kinds  of  turpentine,  which  however, 
is  so  ?ery  similar  that  a  few  words  will 
suffice. 

The  Strasburgh  turpentine,  the  produce 
of  the  silver  fir,  is  the  most  fragrant  of  all 
the  pipe  turpentines,  and  only  inferior  to 
the  true  Chio,  but  it  is  not  often  seen  in 
the  shops.  It  is  obtained  by  rude  incision 
of  the  bark  by  the  peasants  in  the  va&t 
pine  forests  on  the  western  Alps.  The 
first  cut  is  made  as  high  as  the  hatchet 
will  reach,  and  these  are  renewed  an- 
nually from  above  downwards  to  within  a 
foot  of  the  ground.  But  the  finest  kind 
of  turpentine  yielded  by  this  tree,  is  that 
which  exudes  from  soft  tubercles  or  swell- 
ings of  the  inner  bark.  The  peasants  car- 
rv  with  them  a  large  cow's  horn,  with  the 
point  of  which  they  pierce  these  tubercles 


and  collect  the  juice  in  its  hollow.  Only 
a  few  drops  are  yielded  from  each  tuber- 
cle, so  that  this  turpentine  is  rare,  and 
bears  a  higher  price.  It  is  called  techni- 
cally Bigoin  or  Oil  of  Pine,  and  when 
thickened  by  exposure  to  the  air,  it  re- 
mains clear  like  mastich,  whereas  the  tur- 
pentine obtained  from  the  same  tree  by 
incision  of  the  bark,  becomes  white  and 
opake  by  age. 

The  true  Venice  turpentine,  or  resin  of 
the  larch,  is  obtained  from  the  Tyrol,  and 
Savoy,  and  also  from  Dauphiny,  by  boring 
holes  about  an  inch  in  diameter,  with  a 
gentle  descent,  in  the  most  knotty  parts 
of  the  tree.  To  these  are  adapted  long 
perforated  pegs,  which  serve  as  gutters 
to  convey  the  juice  into  troughs  placed 
beneath.  It  is  yielded  during  the  whole 
of  the  summer,  and  is  simply  purified  by 
straining  through  hair  sieves.  A  full- 
grown  larch  will  sometimes  yield  seven 
or  eight  pounds  of  turpentine  annually  for 
forty  or  fifty  years. 

The  Carpathian,  or  Hungary  balsam,  is 
obtained  from  the  stone  pine  in  Hungary 
and  the  Tyrol,  either  by  breaking  off  the 
twigs  of  the  tree,  and  collecting  in  a  glass 
the  fine  resin  that  exudes;  or  by  boiling  the 
ends  of  the  fresh  boughs  in  water,  when 
the  balsam  rises  to  the  top.  The  former 
method  yields  by  far  the  best.  This  is  a 
whitish,  pellucid,  and  very  fluid  turpen- 
tine, which  does  not  harden  by  keep- 
ing. 

The  Canada  balsam  is  a  transparent 
whitish  juice,  of  the  consistence  of  Copai- 
va  balsam,  and  of  a  very  fragrant  smell 
and  bitterish  taste,  obtained  from  tiie 
balm  of  Gilead  fir,  and  imported  from 
Canada :  but  the  mode  of  collection  is  not 
well  known. 

To  return  to  the  various  operations  per- 
formed with  the  common  turpentine,\vhich 
as  above  mentioned  is  obtained  in  two  de- 
grees of  liquidity,  the  most  fluid  being 
called  properly  turpentine,  and  the  least 
fluid  having  the  name  of  barras  or  galipot 
in  the  south  of  Trance,  whence  it  is  pro- 
duced. 

The  turpentine  contains  a  number  of 
impurities  entangled  in  its  substance, 
from  which  it  is  purified  by  two  methods. 
One  of  them  is  to  inclose  it  in  a  cask  per- 
forated at  bottom,  and  by  exposure  to  a 
hot  sun  it  becomes  so  fluid  as  to  filter 
through,  which  gives  the  finest  and  most 
valued  turpentine.  The  other  method  is 
to  heat  it  moderately  in  a  large  copper, 
till  it  is  quite  liquid,"  and  then  to  filter  it 
through  a  strainer  made  of  rows  of  straws 
laid  close  to  each  other.  This  gives  it  a 
golden  colour. 


TUR 


TUR 


The  harder  turpentine,  or  Barms,  is 
also  purified  in  the  latter  mode,  but  in- 
stead of  being  merely  liquefied  in  the 
copper  heat  is  continued  for  some  time, 
till  part  of  the  essential  oil  is  so  far 
dissipated,  that  a  little  of  it  cooled  on  a 
piece  of  wood  may  be  crushed  to  powder 
by  the  fingei  s.  It  is  then  strained  through 
straw  while  hot,  and  the  pure  resin  on 
cooling  hardens  into  a  yellow  opake  muss, 
which  is  called  Brai-sec,  or  Rase.  This 
is  sometimes  sold  as  Burgundy  pitch,  which 
however  appears  to  be  properly  the  pro- 
duct of  another  species  of  pine,  as  we 
shall  presently  mention.  This  opake  yel- 
low brown  resin  is  rendered  transparent, 
and  of  a  fine  clear  amber  yellow,  by  mix- 
ing it  when  melted  with  about  an  eighth 
of  boiling  water,  and  stirring  it  incessant- 
ly for  a  considerable  time  till  the  water  is 
cold.  The  resin  is  then  cast  into  moulds 
and  cooled. 

Essential  Oil  of  Turpentine. 
This  valuable  oil  is  prepared  largely, 
both  in  the  countries  where  the  turpen- 
tine is  extracted,  and  from  turpentine  im- 
ported into  this  country.  The  process  is 
the  following :  an  alembic,  with  a  worm 
and  cooler,  is  used,  precisely  of  the  same 
construction  as  what  is  employed  for  the 
distillation  of  spirits;  this  is  filled  with 
turpentine  and  water  in  due  proportions, 
and  the  volatile  part  after  distillation  is 
found  to  consist  of  oil  of  turpentine  swim- 
ming on  water.  This  oil  is  perfectly  lim- 
pid and  colourless,  has  a  very  strong 
smell,  a  bitterish  taste,  is  extremely  in- 
flammable, and  in  short  possesses  all  the 
properties  of  the  other  essenial  oils.  It  is 
employed  in  immense  quantities  in  a  va- 
riety of  varnishes  and  similar  prepara- 
tions ;  but  for  the  finer  purposes,  such 
(for  example)  as  that  of  dissolving  gum 
copal,  it  is  necessary  to  rectify  it  by  a  se- 
cond distillation  with  water,  in  a  still, 
using  a  very  gentle  heat,  and  keeping 
apart  the  first  product  which  is  the  best. 
From  250  pounds  of  good  turpentine, 
about  60  pounds  of  oil  may  be  obtained. 

Common  Rosin,  Yellovo  Resin,  Colophony. 

The  residue  from  the  distillation  of  the 
oil  of  turpentine,  is  an  opake,  brittle,  light 
yellow  mass,  much  less  clammy  and  cohe- 
sive than  inspissated  turpentine,  and  re- 
quiring a  greater  heat  for  fusion  :  it  is  the 
common  resin  or  rosin  of  the  shops.  It  is 
also  called  by  the  French  Brai-sec,  as 
well  as  the  boiled  galipot,  or  harder  tur- 
pentine ;  but  the  latter  is  more  esteemed, 
as  it  still  contains  a  good  deal  of  essen- 
tial oil,  and  is  fitter  for  most  of  the  pur- 
VOL.  II. 


poses  for  which  the  terebinthinate  sub- 
stances are  employed.  When  common 
rosin  is  boiled  with  water  for  a  time,  it 
becomes  yellow  and  transparent,  and  BH 
then  the  rosin  used  by  musicians  to  rub 
the  bows  and  strings  of  violins.  When 
common  rosin  is  kept  in  fusion  for  a  con- 
siderable time,  it  becomes  of  a  browner 
colour,  is  still  harder,  and  less  adhesive 
to  the  fingers  when  cold,  and  is  then  call- 
ed Black  rosin,  or  Colophony,  and  this  is 
the  ultimate  point  to  which  the  inspissa- 
tion  of  turpentine  is  carried. 

There  are  orfier  less  important  varieties 
in  the  products  of  common  turpentine, 
which  it  is  needless  to  describe. 

A  very  fine  essential  oil  is  prepared  in 
some  parts  of  Germany,  by  distillation  of 
the  green  tops  and  cones  of  the  stone  pine 
(Pinus  cembra)  which  is  known  in  medi- 
cine by  the  name  of  Oleum  tcmplinum,  or 
properly,  Krumholzoel,  and  is  an  approved 
remedy  for  a  number  of  complaints  It  is 
somewhat  greenish,  or  sometimes  of  a 
golden  yellow,  very  fragrant  and  aro- 
matic. 

The  true  Burgundy  pitch  is  a  brittle, 
opake,  light  yellow,  or  sometimes  reddish 
brown  resin,  of  a  fine  terebinthinate  smell 
and  taste,  which  is  chiefly  imported  from 
Saxony,  and  is  collected  in  quantity  in  the 
neighbourhood  of  Neufchatel  from  the 
Norway  spruce  fir. 

Incisions  are  made  in  the  usual  manner, 
and  the  surface  of  the  wood  laid  bare, 
which  is  soon  covered  with  a  turpentine, 
less  liquid  than  the  common  sort,  and 
which,  therefore,  soon  concretes  on  the 
incision  without  flowing  down.  This  is 
pic  ked  off,  and  when  a  sufficient  quantity 
is  collected,  it  is  put  with  water  into  large 
boilers,  melted,  and  then  strained  under  a 
press,  through  close  cloths  into  barrels, 
in  which  it  is  transported  for  sale.  Bur- 
gundy pitch  is  of  such  a  consistence  that 
it  will  barely  soften  by  the  heat  of  the  hu- 
man body,  and  is  much  used  in  plasters. 
It  is  often  adulterated  (as  is  supposed)  by 
a  mixture  of  rosin  and  turpentine. 

Burgundy  pitch  is  also  obtained  from 
the  larch. 

The  substance  commonly  called  Frank, 
incense  {Thus,)  is  a  solid  brittle  resin,  in 
small  roundish  masses,  of  a  brownish  yel- 
low on  the  outside,  and  white  internally. 
It  possesses  the  common  properties  of  the 
turpentines,  and  has  a  very  pleasant  smell 
when  burned.  It  is  supposed  to  exude 
spontaneously  (and  not  by  incision)  from 
the  Norway  spruce,  and  to  undergo  no 
preparation. 

All  the  terebinthinate  substances  above 
described  are  either  nearly  in  the  state  in 
3  R 


TUR 


run 


which  they  exude  from  the  tree,  or  are 
prepared  by  heat  with  the  intervention  of 
a  suitable  apparatus. 

*  There  is  another  product  more  impor- 
tant than  any  other,  especially  in  a  mari- 
time country,  which  is  prepared  by  a  kind 
of  distillation  per  descensum,  with  no  in- 
considerable skill,  but  olten  without  any 
other  apparatus  than  the  substance  itself 
that  yields  it,  and  this  is  common  tar. 

Tar. — Goudron,  French,  is  a  thick  dark 
brown  or  black  resinous  adhesive  juice, 
melted  by  fire  from  the  wood  and  roots 
of  old  pine  and  fir  trees,  during  which 
process  the  wood  itself  is  reduced  to 
charcoal. 

Every  part  of  the  tree  which  is  at  all 
resinous,  is  fit  for  obtaining  tar,  but  in  par- 
ticular it  is  the  red  wood  and  the  hard 
roots  that  yield  the  greatest  quantity  and 
the  best.  As  the  wood  is  entirely  charred 
in  the  process,  all  the  sap  and  other  vola- 
tile parts  must  be  expelled,  most  of  which 
mixes  with  the  turpentiue,  which  sweats 
out  and  constitutes  tar,  and  hence  this 
substance  must  considerably  vary,  in  the 
quality  and  proportion  of  resin,  empyreu- 
matic  oil  and  acid  which  it  contains,  ac- 
cording to  the  age  of  the  tree,  the  soil  on 
which  it  grows,  the  part  selcted,  the  ma- 
nagement of  the  heat,  &c. 

The  extraction  of  tar  from  pine-trees  is 
very  ancient,  being  described  by  Theo- 
phrastus,  Dioscorides,  and  other  old  au- 
thors, and  the  method  of  proceeding  was 
extremely  simple.  Very  large  stacks 
were  made  of  billets  of  pine,  and  covered 
with  turf,  to  prevent  the  volatile  parts 
from  being  dissipated.  They  were  then 
kindled,  and  suffered  to  burn  with  a  low 
smothered  flame;  during  which  the  tar 
melted  out  by  the  heat,  flowed  to  the  bot- 
tom of  the  stack,  and  ran  out  by  a  small 
channel  cut  for  the  purpose.  A  very  large 
proportion  of  the  tar  actually  made  in 
Norway,  and  the  other  Baltic  countries, 
is  prepared  in  this  rude  manner.  The 
stacks  are  built  upon  the  slope  of  a  hill, 
covered  with  moss  and  turf,  kindled,  and 
the  tar  that  oozes  out  is  collected  and  put 
into  barrels. 

But  a  more  economical  and  scientific 
method  is  practised  in  France,  and  Swit- 
zerland, which  is  to  heat  the  wood  in  large 
brick  ovens  built  for  the  purpose,  where- 
by the  wood  is  charred  much  more  equal- 
ly, and  the  tar  is  of  a  more  uniform,  and 
probably  a  better  quality.  The  following 
is  the  method  of  proceeding  in  the  Valais: 
the  pines  are  previously  felled  in  the  pre- 
ceding year,  that  the  wood  may  be  dry 
enough  when  wanted,  and  the  outer  bark 
and  twigs  being  stripped  off,  the  rest  of 
the  tree  is  cut  up  into  billets  of  tolerably 


equal  size.  The  oven  is  built  of  stone  or 
brick,  in  the  form  of  an  egg  standing  on 
its  small  end.  The  floor  is  made  either 
of  a  single  stone  scooped  out  into  a  hoi 
low,  or  of  several  joined  very  accurately. 
On  one  side  of  it,  about  five  inches  above 
the  lowest  part,  is  a  hole  in  which  a  large 
gun  barrel  is  thrust,  which  serves  to  con- 
vey oil'  the  liquid  tar  as  it  collects.  A 
large  iron  grate  is  laid  at  the  bottom  of 
the  oven.  The  largest  of  these  ovens  are 
about  ten  feet  high,  and  five  or  six  feet  in 
the  largest  diameter.  To  charge  the 
oven,  bundles  of  these  billets  are  thrown 
in,  and  the  wood  spread  as  evenly  as  pos- 
sible, filling  the  interstices  with  the  chips, 
till  it  nearly  reaches  the  top.  The  whole 
is  then  covered  with  a  layer  of  chips,  and 
the  top  of  the  furnace  is  closed  with  flat 
stones;  heaped  one  upon  the  other,  gra- 
dually lessening  the  opening,  and  form- 
ing a  kind  of  vaulted  chimney,  the  mouth 
of  which  is  four  or  five  inches  across. 
The  dry  chips  at  top  of  the  furnace  are 
then  set  on  fire,  and  the  heat  spreads 
downwards  till  the  whole  of  the  charge 
is  judged  to  be  sufficiently  kindled.  The 
chimney  is  then  entirely  closed  with  a 
large  stone,  and  wet  earth  is  heaped  on 
the  stones  at  top,  and  thrown  on  wherever 
the  smoke  bursts  out  too  strongly.  The 
melting  now  begins,  the  tar  falls  down 
to  the  bottom,  fills  the  hollow  of  the 
floor,  (which  last  detains  any  bits  of 
wood  and  other  impurities)  and  runs  of!" 
through  the  gun  barrel  into  casks  placed 
to  receive  it  Some  skill  is  required  in 
managing  the  fire,  which  must  sometimes 
be  refreshed  by  letting  in  a  small  draught 
of  air  through  small  holes  left  for  the 
purpose  in  the  sides  of  the  kiln.  When 
the  process  is  over,  the  wood  is  found 
completely  charred,  and  is  taken  out,  and 
the  oven  after  being  cleared  out  is  again 
filled.  It  is  found  that  the  red  wood  and 
knots,  which  are  the  richest  in  the  resin, 
will  yield  about  a  fourth  of  their  weight 
of  tar,  but  the  general  average  of  pro- 
duct is  about  10  or  12  per  cent,  of  the 
weight  of  the  whole  charge.  After  each 
process,  a  quantity  of  lamp»black  is  col- 
lected beneath  the  stones,  that  form  the 
vault  of  the  temporary  chimney. 

This  latter  substance  is  also  another 
product  from  the  pine,  and  in  the  large 
way  is  procured  by  a  different  process,  as 
described  under  the  article  Carbon. 

A  substance  somewhat  resembling  tar, 
called  Brai-gras,  and  much  used  in  the 
French  ports  for  careening  ships,  is  made 
in  the  following  way.  The  oven  above 
described  is  charged  with  alternate  lay- 
ers of  chips  of  green  wood,  and  billets  ol 
dry,  and  all  the  refuse  matter  of  turpen- 


TUR 


TUT 


tine,  the  straw  through  which  it  is  strain- 
ed, and  the  like.  Over  the  whole  is  laid 
a  stratum  of  brai-sec,  or  rosin,  and  the 
gun-barrel  pipe  is  stopped  up,  and  not 
topped  till  the  whole  of  the  wood  is  re- 
duced to  charcoal.  The  vault  of  the 
oven  is  also  covered  more  carefully  after 
the  charge  is  sufficiently  kindled,  and  the 
whole  process  is  carried  on  more  slow iy. 
The  heat  of  the  fire  melts  the  rosin  at 
Top,  which  mixes  with  the  resinous  sap,  I 
and  the  whole  collects  into  a  dark  resi- 
nous liquid  at  the  bottom.  When  suffi- 
ciently cooled,  it  is  drawn  oft'  and  barrel- 
led. The  brai-gras  is  of  an  intermediate 
consistence,  between  tar  and  rosin. 

Pitch. — The  substance  called  pitch  in 
this  country,  is  simply  tar,  inspissated  to 
the  requisite  degree  by  boiling. 

It  does  not  appear,  however,  that  the 
French  have  this  precise  preparation,  as 
the  substance  called  Poix  is  made  either 
by  melting  together  due  proportions  of 
rosin  with  tar,  or  else  by  filling  a  kind  of 
oven  with  various  refuse  matters  from  the 
turpentine,  such  as  the  straw  through 
which  it  has  strained,  together  with  the 
coarse  strainings,  chips  of  bark,  soaked  in 
turpentine,  the  broken  earth  of  the  moulds 
in  which  the  resin  collects,  &c  kindling  it 
till  all  the  resin  fulls  down  into  a  reser- 
voir, and  continuing  the  heat  till  it  is  suf- 
ficiently inspissated.  This  forms  a  hard 
black  mass  called  Poix  dure,  or  Pegle. 

The  pitch  made  in  England  by  boil- 
ing down  tar  to  the  proper  consistence,  is 
now  performed  near  London,  and  in  some 
other  parts,  in  a  still  with  a  worm-tub  at- 
tached to  it,  in  order  to  collect  the  valua- 
ble volatile  products  of  the  tar.  The  pro- 
cess is  the  following  :  the  barrels  of  tar 
being  of  various  consistence,  their  con- 
bents  are  first  emptied  into  a  copper,  and 
gently  heated  and  well  stirred,  to  render 
them  thin  and  uniform.  The  tar  is  then 
Jaded  into  the  still,  passing  through  a 
sieve  to  keep  out  chips  of  wood  and  other 
impurities. 

When  the  still  is  properly  luted,  the 
fire  is  kindled  and  kept  up  very  moderate 
for  three  hours,  as  the  tar  is  very  apt  to 
boil  up  in  the  early  part  of  the  process. 
The  first  product  that  distils  over  is  prin- 
cipally a  brown  acid  water,  mixed  howe- 
ver with  a  good  deal  of  oil.  As  the  pro- 
cess advances,  and  the  heat  is  increased, 
the  quantity  of  acid  lessens,  and  that  of 
oil  increases,  and  towards  the  end  of  the 
distillation  the  product  is  chiefly  oil.  The 
length  of  the  process  varies  according  to 
the  quality  and  hardness  of  the  pitch  re- 
quired. In  general,  a  still  that  holds 
about  600  gallons  will  work  IB  or  20  bar- 
rels of  tar  in  8  hours,  the  produce  of 


which  will  be  about  10  barrels  of  pitch 
(or  22  cwt.)  176  gallons  of  oil;  and 
about  40  gallons  of  acid.  The  pitch  re- 
mains in  the  still  for  12  hours,  after  which 
it  is  barrelled,  and  hardens  as  it  cools. 

The  oil  and  acid  water,  which  distil 
over  do  not  mix,  so  that  they  may  be  ea- 
sily separated  by  decantation.  The  oil  is 
a  brownish  inferior  kind  of  oil  of  turpen- 
tine, which  is  very  usef  ul  in  painting  ships 
I  and  other  coarse  out-door  work.  The 
acid  is  a  very  strong  brownish  empyreu- 
matic  acid,  which  appears  very  closely  to 
resemble  the  pyroligneous  acid  obtained 
from  the  distillation  of  wood,  during  its 
conversion  to  charcoal,  and  is  now  em- 
ployed pretty  largely  in  composing  seve- 
ral of  the  mordants  in  calico  printing. 

TURPENTINE  (Chio.)—  This  is  a  ve- 
ry fragrant  resin,  obtained  sparingly  by 
incision  of  the  bark  of  the  Pistacia  Ttre- 
binthus,  a  small  tree  growing  in  the  isle  of 
Chio,  and  in  many  other  parts  of  the  Le- 
vant. 

It  is  a  thick  and  tenacious  substance, 
whitish,  nearly  transparent,  highly  fra- 
grant, and  almost  tasteless.  It  is  seldom 
found  genuine,  the  common  Chio  turpen- 
tine of  the  shops  being  largely  adulterat- 
ed with  the  finer  sorts  of  the  pine  turpen- 
tines 

TUTENAG,  an  alloy  of  copper— This 
name  is  given  in  India  to  the  semi-metal 
zinc.  It  is  sometimes  applied  to  denote 
a  white  metallic  compound  brought  from 
China,  called  also  Chinese  copper,  the  art 
of  making  which  is  not  known  in  Europe. 
It  is  very  tough,  strong,  malleable,  may 
be  easily  cast,  hammered,  and  polished  ; 
and  the  better  kinds  of  it,  when  well  ma- 
nufactured,  are  very  white,  and  not  more 
disposed  to  tarnish  than  silver  is.  Three 
ingredients  of  this  compound  may  be  dis- 
covered by  analysis ;  namely,  copper, 
zinc,  and  iron. 

Some  of  the  Chinese  white  copper  is 
said  to  be  merely  copper  and  arsenic. 

Mr.  Engestrom,  in  the  Memoirs  of 
Stockholm  for  the  year  1775,  quoted  by 
Kirwan,  has  given  us  an  analysis  of  a  tu- 
tenag  ore  from  China.  It  was  of  a  white 
colour,  interspersed  with  red  streaks  of 
oxide  of  iron,  and  so  brittle  as  to  be  easi- 
ly broken  betwixt  the  fingers.  In  the  dry 
way  it  exhibited  the  same  appearances  a* 
zinc  spar,  except  that  it  lost  no  part  of 
its  weight.  It  was  soluble  in  the  mineral 
acids,  particularly  with  the  assistance  of 
heat,  and  with  the' sulphuric,  afforded  sul- 
phates both  of  zinc  and  iron.  The  quan- 
tity of  carbonic  acid  was  so  small  as  to 
be  absorbed  by  solution.  It  contained  in 
various  specimens  from  60  to  90  per  cent, 
of  zinc ;  the  remainder  was  iron,  and  a 


ULT 


ULT 


small  proportion  of  clay.  This  variety 
of  calciform  ores,  which  was  mixed  with 
a  notable  proportion  of  iron,  was  also  dis- 
covered in  Germany  by  Mr.  Bindheim, 
who  found  it  to  consist  of  zinc,  a  little 
iron,  and  silex. — 4  B'erl.  Schrift.  400. 

TUTTY. — A  metallic  substance,  va- 
rious in  its  composition  and  properties, 
which  nevertheless  appear  to  depend  on 
the  presence  of  zinc.  The  better  sorts 
of  lutty,  according1  to  Neumann,  are  in 
semi-cylindiical  concave  pieces,  like  the 
bark  of  a  tree  ;  ponderous  and  somewhat 
sonorous ;  moderately  compact,  and  ge- 
nerally not  easy  to  break;  of  an  ash  or 
mouse-gray  colour,  often  with  yellow  or 
green  variegations ;  pretty  smooth  on  the 
inside,  full  of  cavities  or  protuberances 
on  the  outside.  The  entire,  compact, 
gray  pieces  are  preferred;  the  broken, 
powdery,  crumbly,  yellow,  or  reddish,  re- 
jected. Boeder  relates,  that  Tulty  has  a 
sharp  taste,  but  no  such  taste  is  percept- 
ible in  the  English. 

Wiegleb  affirms,  that  the  matter  which 
in  the  fusion  of  brass  is  deposited  over  the 
melted  metal,  is  called  tutty  ;  but  Neu- 
mann made  various  unsuccessful  inqui- 
ries relative  to  its  origin,  and  the  place 
where  it  may  be  produced.  That  it  is  not 
produced  at  Goslar,  or  Schneeberg,  or  at 
any  of  the  considerable  founderies  of 
brass,  bronze,  bell -metal,  &c.  in  Germa- 
ny, Holland,  France,  Italy,  and  England, 
he  affirms  from  his  own  experience.  He 
therefore  concludes,  that  it  is  an  artificial 


production,  expressly  made  up  of  the  ox 
ide  of  zinc  with  clay  and  other  matters. 

TYPE  METAL. — The  basis  of  type 
metal  for  printers  is  lead,  and  the  princi- 
pal article  used  in  communicating  hard- 
ness is  antimony,  to  which  copper  and 
brass  in  various  proportions  are  added. 
The  properties  of  good  type  metal  are, 
that  it  should  run  freely  into  the  mould, 
and  possess  hardness  without  being  ex- 
cessively brittle.  The  smaller  letters  are 
made  of  a  harder  composition  than  those 
of  a  larger  size.  It  does  not  appear,  that 
our  type  founders  are  in  possession  of  a 
good  composition  for  this  purpose.  The 
principal  defect  of  their  composition  ap- 
pears to  be,  that  the  metals  do  not  uni- 
formly unite.  In  a  piece  of  casting  per- 
formed at  one  of  our  principal  founde- 
ries, the  thickness  of  which  was  two 
inches,  we  found  one  side  hard  and  brittle 
when  scraped,  and  the  other  side,  consist- 
ing of  nearly  half  the  piece,  was  soft  like 
lead.  The  transition  from  soft  to  hard 
was  sudden,  not  gradual.  If  a  parcel  of 
letter  of  the  same  size  and  casting  be  ex- 
amined, some  of  them  are  brittle  and 
hard,  and  resist  the  knife,  but  others  may 
be  bent  and  cut  into  shavings.  It  may  ea- 
sily be  imagined,  that  the  duration  and 
neatness  of  these  types  must  considera- 
bly vary.  We  have  been  informed,  but  do 
not  know  the  fact,  that  the  t\pes  cast 
in  Scotland  are  harder  and  more  uni- 
form in  their  qualities. 

TYPE-FOUNDERY.  See  Founders 


u. 


ULTRA -MARINE.  Outremire,  French. 
— This  precious  colour,  so  remarkable  for 
its  beauty  and  durability,  is  a  pure  deep 
sky  blue.  It  is  capable  of  bearing  a  low 
red  heat  without  injury,  and  it  is  not  sen- 
sibly impaired  by  the  action  of  the  air  and 
w  eather.  It  is  the  colouring  matter  of  the 
mineral  already  described  under  the  name 
Lapis  Lazuli,  and  appears,  according  to 
an  analysis  by  Klaproth,  to  consist  of  lit- 
tle else" than  oxide  of  iron.  The  method 
in  which  this  pigment  is  separated  from 
the  earthy  parts  of  the  above  mineral  is 
as  follows.  Let  the  lapis  lazuli  be  heat- 
ed just  to  redness,  and  then  suddenly 
quenched  in  cold  water,  and  let  this  be 
repeated  two  or  three  times  till  the  stone 
becomes  almost  friable;  then  let  it  be 
ground  down  with  a  few  drops  of  water 
in  a  clean  iron  mortar,  or  still  better,  in 
an  agate  one,  till  it  is  reduced  to  a  per- 


fectly impalpable  powder".  Then  take 
one  pint  of  linseed  oil,  warm  it  over  the 
fire  in  a  clean  vessel,  and  add  one  pound 
of  bees-wax,  one  pound  of  turpentine, 
half  a  pound  of  rosin,  and  half  a  pound 
of  gum  mastich  :  keep  the  ingredients 
over  the  fire,  with  constant  stirring  till 
they  are  melted  and  thoroughly  incorpo- 
rated together  ;  the  result  will  be  a  tena- 
cious adhesive  mass.  Of  this  take  any 
quantity,  6  oz.  for  example,  melt  it  and 
pour  it  into  a  warm  clean  mortar ;  then 
sprinkle  upon  it  3  oz  of  pulverized  lapis 
lazuli,  and  incorporate  it  thoroughly  by 
lone-  beating  with  the  pestle  ;  this  being 
done,  pour  in  some  water,  and  again 
work  it  about  in  the  same  manner  as  be* 
fore :  in  a  short  time  the  water  will  be- 
come charged  with  the  blue  colouring 
matter;  it  must  then  be  poured  into  a 
clean  tall  glass,  and  replaced  by  fresh.. 


URA 


proceeding  in  this  manner  till  the  paste 
will  give  out  no  more  colour  on  the  addi- 
tion of  fresh  water.  By  standing  a  few 
days,  the  colour  will  subside  from  the 
water  in  which  it  was  suspended;  the 
clear  fluid  being  then  decanted  off,  and 
the  rest  got  rid  of  by  evaporation,  there 
will  remain  a  deep  blue  powder  which  is 
ultramarine.    See  Colour-making. 

UMBER. — There  are  two  kinds  of 
umber,  the  one  called  Cologne  Umber,  is 
a  variety  of  peat  or  of  earthy  brown  coal. 
There  are  large  beds  of  it  wrought  in  the 
neighbourhood  of  Cologne,  principally  as 
an  article  of  fuel ;  a  pretty  considerable 
quantity  is  also  imported  into  Holland, 
where  it  is  used  in  the  manufacture,  or 
more  properly  in  the  adulteration  of 
snufF,  for  which  purpose  it  appears  to  be 
better  than  the  common  peat  of  the  coun- 
try ;  a  still  smaller  quantity  is  consumed 
by  the  paint-makers. 

The  colour  of  this  vegetable  umber  is 
a  warm  somewhat  pinkish  brown,  and  is 
an  useful  ingredient  to  the  painter  in  wa- 
ter colours. 

The  second  kind  of  umber  goes  by  the 
name  of  Turkish  umber,  and  appears  to 
be  a  variety  of  the  iron  ore  called  brown 
ironstone  ochre.  A  specimen  from  Cy- 
prus was  analysed  by  Klaproth,  and  af- 
forded him, 

48  Oxide  of  iron 

20  Oxide  of  manganese 

13  Silex 

5  Alumine 

14  Water 

100 

See  Colours. 

UNDERSHOT-MILLS.  See  Mecha- 
nics. 

UK  AX-GLIMMER. — An  ore  of  ura- 
nium, formerly  called  green  mica,  a^nd  by 
Werner  chalcolite.  See  the  following  ar- 
ticle. 

UR.VNTTE,  or  URANIUM. — A  new 
metallic  substance  discovered  by  the  ce- 
lebrated Klaproth  in  the  mineral  called 
Peek  blende.  In  this  it  is  in  the  state  of 
sulphuret.  But  it  likewise  occurs  as  an 
oxide  in  the  green  mica,  or  uran-glimmer, 
and  in  the  uran-ochre. 

The  uran-glimmer  is  in  thin  leaves,  or 
small  quadrangular  tables  ;  of  an  emerald 
green,  lemon-yellow,  and  sometimes  sil- 
ver-white colour ;  more  or  less  transpa- 
rent ;  soft  and  easily  broken  ;  specific  gra- 
vity from  2.19  to  3.1.  This  is  nearly  pure 
oxide  of  uranium,  but  sometimes  "conta- 
minated with  a  little  copper,  which  ap- 
pears to  give  it  a  green  colour.  The  re- 
verend Mr.  Gregor  found  oxide  of  lead, 


lime,  and  silex,  in  some  Cornish  speci- 
mens. 

The  uran-ochre  is  generally  an  incrus- 
tation or  efflorescence,  of  a  light  yellow 
colour,  sometimes  tinged  green,  brown, 
or  i -cel.  Specific  gravity  3  2.  This  too  is 
nearly  pure  oxide  of  uranium,  mixed 
with  a  little  oxide  of  iron  when  of  a  red 
or  green  colour. 

By  treating  the  ores  of  the  metal  with 
the  nitric  or  nitromuriatic  acid,  the  oxide 
will  be  dissolved  ;  and  may  be  precipitat 
ed  by  the  addition  of  a  caustic  alkali.  It 
is  insoluble  in  water,  and  of  a  yellow  co- 
lour; but  a  strong  heat  renders  it  of  a 
brownish  gray. 

To  obtain  ii  pure,  the  ore  should  be 
treated  with  nitric  acid,  the  solution  eva- 
porated to  dryness,  and  the  residuum 
heated,  so  as  to  render  any  iron  it  may 
contain  insoluble.  This  being  treated 
with  distilled  water,  ammonia  is  to  be 
poured  into  the  solution,  and  digested 
with  it  for  some  time,  which  will  precipi- 
tate the  uranium  and  retain  the  copper. 
The  precipitate,  well  washed  with  ammo- 
nia, is  to  be  dissolved  in  nitric  acid,  and 
crystallized.  The  green  crystals,  dried 
on  blotting  paper,  are  to  be  dissolved  in 
water,  and  recrystallized,  so  as  to  get  rid 
of  the  lime.  Lastly,  the  nitrate,  being 
exposed  to  a  red  heat,  will  be  converted 
into  the  yellow  oxide  of  uranium. 

It  is  very  difficult  of  reduction.  Fifty 
grains,  after  being  ignited,  were  formeci 
into  a  ball  with  wax,  and  exposed,  in  a 
well-closed  charcoal  crucible,  to  the  most 
vehement  heat  of  a  porcelain  furnace,  the 
intensity  of  which  gave  170°  on  Wedge  - 
wood's  pyrometer.  Thus  a  metallic  but- 
ton was  obtained,  weighing  28  grains,  of 
a  dark  gray  colour,  hard,  firmly  coher- 
ing, fine-grained,  of  very  minute  pores, 
and  externally  glittering.  On  filing  it,  or 
rubbing  it  with  another  hard  bodv,  the 
metallic  lustre  has  an  iron  gray  colour ; 
but  in  less  perfect  assays  it  verges  to  a 
brown.  Its  specific  gravity  was  8.1.  Bu- 
cholz,  however,  obtained  it  as  high  as 
9.0. 

When  heated  to  redness  in  an  open  ves 
sel,  it  undergoes  a  species  of  combustion, 
and  is  soon  converted  into  a  grayish  black 
powder,  containing  about  5  per  cent,  ci 
oxigen.  According  to  Bucholz,  it  forms 
six  distinct  oxides,  in  the  following  order 
of  succession,  as  marked  by  their  co- 
lours ;  grayish  black,  dark  gray  inclining 
to  violet,  greenish  brown,  grayish  green, 
orange,  and  lemon-yellow. 

The  oxide  is  soluble  in  dilute  sulphu- 
ric acid  gently  heated,  and  affords  lemon- 
coloured  prismatic  crystals.  Its  solution 
in  muriatic  acid,  in  which  it  is  but  imper- 


VAL 


VAL 


fectly  soluble,  affords  yellowish  green 
rhomboidal  tablets.  Phosphoric  acid  dis- 
solves it,  but  after  some  time  the  phos- 
phate, falls  down  in  a  flocculent  form,  and 
of  a  pale  yellow  colour. 

It  combines  with  verifiable  substances, 
and  gives  them  a  brown  or  green  colour. 


On  porcelain,  with  the  usual  flux,  it  pro- 
duces an  orange. 

URANOCHE — An  ore  of  uranium, 
containing  this  metal  in  the  oxided  state 
See  the  preceding  article. 

USQUEBAUGH.  SeeDisxiLLED  Spi- 
rits. 


V. 


VALVE.  The  use  of  valves  has  al- 
ready been  mentioned  when  treating  of 
sundry  engines  for  raising  water :  we 
shall  here  add  a  few  remarks  on  the  dif- 
ferent kinds  of  valves.  There  are  three 
kinds  of  valves,  the  clack-valve,  the  but. 
terfij. valve,  and  the  button  or  tail-vr<lve. 

The  Clack-Valve. 
Is  of  all  others  the  most  obvious  and 
common.  It  consists  merely  of  a  leather 
flap  covering  the  aperture,  and  having  a 
piece  of  metal  on  the  upper  side,  both  to 
strengthen  and  to  make  it  heavier,  that 
it  may  shut  of  itself.  Sometimes  the 
hinge  is  of  metal.  The  hinge  being  liable 
to  be  worn  by  such  incessant  motion,  and 
as  it  is  troublesome,  especially  in  deep 
mines,  and  under  water,  to  undo  the  joint 
of  the  pump,  in  order  to  put  in  a  new  valve, 
it  is  frequently  annexed  to  a  box  like  a 
piston,  made  a  little  conical  on  the  out- 
side, and  dropt  into  a  conical  seat,  made 
for  it  in  the  pipe,  where  it  sticks  fast ;  and 
to  draw  it  up  again,  there  is  a  handle  like 
that  of  a  basket,  fixed  to  it,  which  can  be 
laid  hold  of  by  a  long  grappling-iron.  The 
only  defect  of  this  valve,  is,  that  by  open- 
ing very  wide,  when  pushed  up  by  the 
stream  of  water,  it  allows  a  good  deal  to 
go  back  during  its  shutting  again. 

The  Butterfly-valve. 
Is  free  from  most  of  these  inconvenien 
ces,  and  seems  to  be  the  most  perfect  of 
the  clack-valves.  It  consists  of  two  semi- 
circular flaps,  revolving  round  their  dia- 
meters, which  are  fixed  to  a  bar  placed 
across  the  opening  through  the  piston. — 
Some  engineers  make  their  great  valves 
of  a  pyramidal  form,  consisting  of  four 
clacks,  whose  hinges  are  in  the  circumfe- 
rence of  the  watery-way,  and  which  meet 
with  their  points  in  the  middle,  and  are 
supported  by  four  ribs,  which  rise  up 
from  the  sides,  and  unite  in  the  middle. 
This  is  a  most  excellent  form,  affording  a 
more  spacious  water-way,  and  shutting 
very  readily. 


The  Button,  or  Tail-Valve. 

It  consists  of  a  plate  of  metal  turned 
conical  on  the  edge,  so  as  exactly  to  fit 
the  conical  cavity  of  its  box.  A  tail  pro- 
jects from  the  under  side,  which  passes 
through  a  cross  bar  in  the  bottom  of  the 
box,  and  has  a  little  knob  at  the  end,  to 
hinder  the  valve  from  rising  too  high. — 
This  valve,  when  nicely  made,  is  unexcep- 
tionable. It  has  great  strength,  and  is 
therefore  proper  for  all  severe  strains  ; 
and  it  may  be  perfectly  tight  by  grinding. 
Accordingly,  it  is  used  in  all  cases  where 
tightness  is  of  indispensable  consequence. 
It  is  most  durable,  and  the  only  kind  that 
wiil  do  for  passages  where  steam  or  hot 
water,  is  to  pass  through. 

In  addition  to  the  valves  mentioned, 
there  are  other  shapes,  as  pyramids,  &c. 
The  pyramid  valve  consists  of  four  trian- 
gular flaps,  which  represents  the  sides 
of  the  pyramid,  and  moves  upon  hinges 
fixed  on  the  circumference  of" the  opening. 
Their  vertices  meet  in  the  middle  of  the 
opening,  and  are  supported  by  lour  bars 
which  meet  in  the  centre.  The  operation 
of  all  kinds  of  valves,  is  on  the  same  prin- 
ciple, viz.  either  to  admit  the  entrance  of 
a  fluid  and  prevent  its  return,  or  per- 
mit it  to  escape,  and  prevent  its  re-en- 
trance. 

VALVE  OF  SAFETY.  The  steam 
valves,  of  steam  engines,  as  they  are  call- 
ed, which  are  adjusted  to  certain  weights 
of  pressure,  in  order  to  prevent  accidents, 
are  called  valves  of  safety.  See  Steam 
Engine.  There  are  also  valves  of  safety 
made  use  of,  in  several  chemical  opera- 
tions. 

VALONEA  is  the  husks  of  the  acorn, 
generally  mixed  with  that  fruit ;  though 
this  diminishes  its  value.  It  is  brought 
to  us  from  Italy  and  the  Levant,  and  used 
as  a  dyeing  ingredient. 

VANILLA  in  commerce,  is  the  pod  of 
a  species  of  epidendrum,  which  is  brought 
to  us  entire,  and  with  the  seeds  in  it,  being 
usually  about  five  or  six  inches  long,  and 
half  an  inch  broad,  and  containing  an  al 


TAP 


VAR 


most  innumerable  quantity  of  minute  and 
glossy  black  seeds. 

The  vanilla  plant  is  a  native  of  Mexico, 
where,  like  the  ivy,  it  grows  to  the  trees 
it  meets  with,  coders  them  almost  entire- 
ly, and  raises  itself  by  their  aid. 

This  plant  produces  but  one  crop  of 
fruit  in  a  year,  which  is  commonly  ripe 
towards  the  end  of  September,  or  eather 
fit  for  gathering;  for  it  is  not  suffered  to 
remain  till  perfectly  mature,  because  it  is 
then  not  so  lit  for  use.  The  pods  grow 
in  pairs,  are  generally  the  thickness  of  a 
child's  finger,  green  at  first  then  yellowish, 
and  turning  to  a  brownish  cast,  when  com- 
pletely ripe.  When  it  is  about  half  chang- 
ed yellow,  it  is  esteemed  better  for  ga- 
thering, than  when  changed  to  a  brown 
colour,  at  which  time  it  splits  and  dis- 
closes its  seeds. 

The  aromatic  odour  that  is  peculiar  to 
them,  cannot  be  obtained  without  prepa- 
ration. This  preparation  consists  in  thread- 
ing several  pods,  and  dipping  them  for  a 
moment  in  a  caldron  of  boiling  water  to 
whiten  them.  They  are  afterwards  sus- 
pended in  a  place  exposed  to  the  open  air, 
and  to  the  rays  of  the  sun.  A  thick  and 
plentiful  liquor  then  distils  from  their  ex- 
tremity, the  exit  of  which  is  facilitated  by 
a  slight  pressure,  repeated  two  or  three 
times  in  the  course  of  the  day.  In  order 
to  retard  the  drying,  which  ought  to  go 
on  slowly,  they  are  rubbed  over  at  seve- 
ral different  times  with  oil,  which  pre- 
serves their  suppleness,  and  keeps  them 
from  insects.  They  are  also  tied  round 
with  a  cotton  thread,  to  prevent  them  from 
opening.  When  they  are  sufficiently  dried 
they  are  rubbed  with  the  hands,  anointed 
with  oil,  and  put  into  a  pot  that  is  var- 
nished, in  older  to  keep  them  fresh.  In 
some  parts  after  gathering  as  before  men- 
tioned, they  scald  the  pods  in  the  follow- 
ing' liquor :  viz.  a  brine  is  made  with  salt 
and  water,  strong, enough  to  bear  an  egg. 
To  this  are  added  a  fourth  part  of  urine, 
and  a  small  quantity  of  quicklime:  these 
are  boiled  together  for  half  an  hour  and 
then  taken  off.  The  vanillas  are  put  into 
this  liquor,  until  thoroughly  scalded,  then 
taken  out  and  dried  in  the  shade.  When 
fit  for  market  they  are  put  up,  from  50  to 
150  in  little  bags. 

Vanilla  is  used  in  the  manufacture  of 
chocolate,  likewise  to  perfume  snuff  and 
other  substances. 

VAPOUR.  The  elastic  fluids,  or  sub- 
tile invisible  matters,  which  fly  off  from 
bodies  subjected  to  chemical  operations 
or  otherwise,  are  called  vapours.  But 
accurate  chemical  writers  confine  this 
appellation  to  such  exhalations,  only  as 
may  be  condensed  into  the  fluid  state  by 


cold,  in  contra-distinction,  to  the  aerial 
fluids,  or  gasses,  of  which  scarcely  any 
are  so  convertible,  by  any  means  in  our 
power. 

VARIATION  OF  THE  COMPASS 

See  Magnetism. 

VARNISHING,  and  LACQUERING, 
the  Jlrt  of —The  number  of  formulae  for 
the  preparation  of  varnishes  is  very  exten- 
sive, and  therefore,  without  troubling  our 
readers  with  a  great  number  of  super- 
fluous receipts,  we  shall  enumerate  those 
which  have  been  approved,  at  the  same 
time  give  some  general  directions  for  fa- 
cilitating the  processes. 

A  varnish,  in  the  most  extensive  appli- 
cation of  the  term,  is  any  fluid,  which 
when  spread  thin  upon  a  solid  substance 
adheres  to  it,  and,  becoming  dry,  forms 
upon  its  surface  a  shining  coating  imper- 
vious  to  the  air  and  to  moisture. 

In  treating  of  this  subject  the  most 
convenient  method  of  arranging  it,  w  ill  be 
according  to  the  nature  of  the  menstrua 
from  which  the  different  varnishes  derive 
their  fluidity.  These  menstrua  are  three 
in  number,  namely  alcohol,  essential  oil, 
and  tat  oil. 

The  solid  substances  which  by  solution 
in  the  above  menstrua,  compose  the  body 
of  the  different  varnishes  are  the  followr- 

1.  Benzoin.  This  substance  is  used  in 
compound  alcoholic  varnishes,  chiefly  on 
account  of  its  fragrant  odour :  by  itself,  it 
forms  a  tenacious  but  soft  varnish,  which 
requires  the  addition  of  some  of  the  hard- 
er resins. 

2-  Lac.  This  is  one  of  the  most  useful 
ingredients  in  alcoholic  varnishes:  it  forms 
a  body  of  great  toughness  and  hardness  : 
the  only  objection  to  it,  is  its  colour,v/hich 
is  a  brownish  red. 

3-  Mastkh.  This  is  a  resin  of  prime 
importance  to  the  varnisher ;  if  well  se- 
lected, it  has  scarcely  any  colour,  and 
possesses  both  toughness  and  hardness  in 
a  very  considerable  degree. 

4.  Jinime.  This  resin  is  employed  in 
some  compound  alcoholic  varnishes,chief- 
ly  on  account  of  its  agreeable  odour. 

5.  Elani.  Of  this  resin  there  are  two 
sorts,  the  Ethiopian  and  South  American. 
The  former  is  greatly  preferable  to  the  lat- 
ter; it  is  of  a  solid  but  tough  consistence,  a 
greenish  colour,  and  possesses  an  odour 
resembling  that  of  fennel;  it  communi- 
cates to  the  compound  varnishes  great 
toughness  and  durability. 

6.  Sar.darach.  This  resin  communicates 
remarkable  splendour  to  alcoholic  var- 
nishes, but  on  account  of  its  softness  re- 
quires to  be  mixed  with  the  harder  and 
tougher  resins. 


VAR 


VAR 


7.  Turpentine.    Almost  all  the  different 


varieties  of  turpentine  are  employed  by 
the  varnisher:  they  affoflt  glossiness  and 
body  at  small  expense,  but  require  the 
admixture  of  some  of  the  harder  resins. 

8.  Gamboge.  9.  Dragon's  blood.  These 
are  never  employed  by  themselves,  but 
are  used  in  small  proportions,  for  the 
purpose  of  colouring-  compound  var- 
nishes, especially  those  used  in  lacquer- 

10.  Copal.  This  valuable  substance  is 
employed  in  all  the  three  kinds  of  varnish, 
to  which  it  communicates  an  uncommon 
degree  of  hardness. 

11.  Amber.  This  is  also  a  very  valua- 
ble ingredient,  but  its  application  is  prin- 
cipally confined  to  the  coloured  and  opake 
oil  varnishes. 

12.  Asphaltum.  This  bitumen  is  ex- 
tensively used  in  the  best  black  oil  var- 
nishes. 

13  Caoutchouc.  This  substance  is  used 
only  in  the  oil  varnish  with  which  bal- 
loons are  covered. 


mig  but  very  sparingly  soluble  by 


Preparation  of  Alcoholic  Varnishes. 

Alcoholic  varnishes  are  prepared  with 
less  trouble  than  others,  they  are  easily 
applied,  they  soon  dry,  and  are  entirely 
tree  from  any  disagreeable  odour ;  on  this 
account  they  are  in  very  general  estima- 
tion. They  are,  however,  very  liable  to 
crack,  or  scale  off,  and  are  incapable  of 
resisting  blows  or  long  continued  friction. 

The  composition  of  these  varnishes, 
though  upon  the  whole  sufficiently  sim- 
ple, requires  a  few  precautions  which  we 
shall  proceed  to  mention.  In  the  first 
place,  care  should  be  taken  not  to  add 
more  resin  than  the  spirit  can  take  up ; 
for  most  resins,  however  homogeneous 
they  may  appear  to  be,  consist  of  parts 
unequally  soluble  in  alcohol;  the  conse- 
quences Of  a  superfluity  of  resin  there- 
fore will  be,  that  the  most  soluble  parts 
alone  will  be  taken  up,  and  the  resulting 
varnish  will  be  found  to  be  much  softer 
and  less  durable  than  if  only  such  a  quan- 
tity of  resin  was  added  as  just  sufficed  to 
saturate  the  alcohol.  Indeed  the  very 
best  way  of  proceeding  is,  to  add  the  re- 
sin by  small  portions  at  a  time,  taking 
care  not  to  add  a  fresh  quantity  lill  the 
whole  of  the  preceding  is  taken  up. 

Secondly,  a  mixture  of  two  or  more  re- 
sins is  soluble  in  a  less  quantity  of  alco- 
hol than  would  have  been  required  for 
the  solution  of  each  separately.  This  is 
particularly  the  case  with  those  com- 
pounds into  which  copal  or  sandarach  en- 
ter; these  substances,  especially  the  for- 


themselves  in  alcohol. 

Thirdly,  much  depends  upon  the  purity 
of  the  alcohol.  If  diluted  to  a  certain  de- 
gree with  water,  it  is  incapable  of  acting 
even  on  the  softest  resins;  and  for  copal 
varnishes  the  highest  possible  degree  of 
rectification  is  absolutely  essential.'  The 
addition  of  camphor  singularly  facilitates 
the  solution  of  copal, and  the  more  intract- 
able resins  ;  but  if  used  in  too  great  a  pro- 
portion, it  makes  the  varnish  mealy,  and 
diminishes  its  tenacity. 

Fourthly,  during  the  solution  of  the  re- 
sins, it  is  expedient  that  they  should  ex- 
pose as  large  a  surface  as  possible  to  the 
action  of  the  spirit ;  for  it  not  (infrequent- 
ly happens,  especially  when  heat  is  ap- 
plied, that  the  resins  run  together  into  a 
tough  mass,  after  which  their  solution 
goes  on  very  slowly  :  this  inconvenience 
may  be  obviated  by  mixing  the  resins 
with  rather  coarsely  pounded  glass. 

The  following  are  some  of  the  most  ap- 
proved receipts  for  alcoholic  varnishes. 

1.  Take  of  clean  mastich  6  ounces  ;  and 
of  sandarach  3  ounce-:,  and  reduce  the 
mixture  to  fine  powder  in  a  clean  Wedg- 
wood mortar  :  to  this  add  4  ounces  of 
coarsely  pounded  glass,  and  pour  the 
mixture  into  a  three  pint  Mask  containing 
a  quart  of  highly  rectified  alcohol :  stop 
the  flask  loosely  with  a  cork,  and  let  the 
ingredients  digest  together  in  a  warm 
room  for  three  days,  shaking  the  mixture 
frequently  in  the  interval.  Then  melt  3 
ounces  of  very  clear  Venice  turpentine, 
by  putting  it  into  a  cup  set  in  hot.  water, 
and  as  soon  as  it  is  perfectly  liquefied, 
pour  it  into  the  alcoholic  solution,  also 
previously  warmed,  and  then  digest  the 
whole  in  hot  water  for  two  hours;  stir- 
ling  it  up  frequently  with  a  rod  of  glass, 
or  a  stick  of  white  wood.  When  the  di- 
gestion is  finished  let  the  flask  stand  quiet 
for  about,  a  week  in  a  warm  room,  and 
after  that  strain  the  varnish  into  a  bottle 
through  a  little  cotton  wool. 

2.  Take  of  copal  that  has  been  lique- 
fied, and  afterwards  very  finely  pounded, 
3  ounces,  of  clean  mastich  3  ounces,  of 
gum  sandarach  6  ounces,  and  of  pounded 
glass  4  ounces  :  mix  the  ingredients  with 
a  quart  of  alcohol  and  digest  them  as  al- 
ready directed:  then  add  2^  ounces  of 
clear  turpentine. 

This  is  a  strong  and  durable  varnish, 
which  may  be  applied  to  chairs  and  other 
articles  of  furniture. 

3.  Take  of  sandarach  4  ounces,  of  seed 
lac  2  ounces,  of  mastich  2  ounces,  and  of 
elemi  1  ounce ;  digest  the  whole  in  a  quart 
of  alcohol  moderately  warm,  and  when 


VAR 

the  solution  is  complete,  add  2  ounces  of 
Venice  turpentine.  This  forms  a  good 
varnish  for  violins  and  other  musical  in- 
struments. 

4.  Take  of  seed  lac  8  ounces,  and  di- 
gest it  for  three  or  four  days  in  a  warm 
place  with  a  quart  of  alcohol ;  when  the 
solution  is  complete,  strain  it  through 
flannel  to  separate  the  impurities,  and  the 
clarified  liquor  is  the  common  iac  varnish. 

5.  Take  of  mastich  half  an  ounce,  of 
white  frankincense  a  quarter  of  an  ounce, 
of  sandarach  half  an  ounce,  of  benzoin 
half  an  ounce,  and  dissolve  the  ingre- 
dients in  a  pint  of  highly  rectified  alco- 
hol :  a  colourless  varnish  is  thus  formed, 
which  is  employed  for  defending  the  sil- 
vering of  clock  faces,  of  barometer  scales, 
and  other  similar  articles,  from  the  action 
of  the  air. 

6.  Take  of  sandarach  6  ounces,  of  ele- 
mi  4  ounces,  of  anime  1  ounce ;  pound  the 
whole  together,  and  then  add  4  ounces  of 
coarsely  pulverized  glass  ;  infuse  the  mix- 
ture in  a  quart  of  rectified  alcohol,  and 
add  at  intervals  as  the  solution  goes  on 
half  an  ounce  of  camphor.  The  result  is 
a  very  good  colourless  varnish  for  boxes 
of  papier  mache,  and  similar  articles. 

7.  A  similar  varnish  to  the  above,  but 
somewhat  coarser,  is  Composed  of  white 
frankincense  6  ounces,  anime  and  elemi  of 
each  2  ounces,  pounded  glass  4  ounces, 
and  a  quart  of  alcohol. 

The  following  account  of  an  excellent 
colourless  copal  varnish  is  by  Mr.  Lenor- 
mand. 

"  All  copal  is  not  fit  for  making  this 
varnish  ;  it  must  therefore  be  selected 
with  care,  and  the  following  method  will 
show  when  it  is  good.  Take  each  piece 
of  copal  separately,  and  let  fall  on  it  a 
single  drop  of  very  pure  essential  oil  of 
rosemary,  not  altered  by  keeping.  Those 
pieces  on  which  the  oil  makes  a  certain 
impression,  that  is  to  say,  which  soften  at 
the  part  that  imbibes  the  oil,  are  good, 
and  should  be  reserved  for  making  var- 
nish.   The  other  ought  to  be  rejected. 

Powder  the  pieces  of  copal  thus  select- 
ed, sift  the  powder  through  a  very  fine 
hair  sieve,  and  put  it  into  a  glass,  on  the 
bottom  of  which  it  must  not  lie  more  than 
a  finger's  breadth  thick.  On  it,  pour  es- 
sence of  rosemary  to  a  similar  height,  stir 
the  whole  together  with  a  stick  for  a  few 
minutes,  the  copal  will  dissolve  into  a  vis- 
cous substance,  and  the  whole  will  form 
a  very  thick  fluid.  Let  it  stand  for  a  cou- 
ple of  hours,  after  which  pour  on  gently 
two  or  three  drops  of  very  pure  alcohol, 
which  you  will  distribute  over  the  oily 
mass  by  inclining  the  glass  in  different  di- 
rections with  averv  gentle  motion.  In 

VOL.  II. 


VAR 

this  way,you  will  effect  their  incorporation. 
Repeat  this  operation,  little  by  little,  till 
the  varnish  is  reduced  to  a  proper  degree 
of  fluidity.  Jtemembei ,  the  first  drops  of 
alcohol  are  the  most  difficult,  and  require 
the  longest  time  to  incorporate ;  and  that 
the  difficulty  diminishes  as  each  succes- 
sive addition  is  incorporated,  or  as  the 
mass  approaches  the  state  of  saturation. 

When  the  varnish  has  attained  the  suit- 
able degree  of  fluidity,  it  is  to  be  suffered, 
to  stand  a  few  days  ;  and  when  it  has  be- 
come very  clear,  the  varnisli  is  to  be  de- 
canted off. 

The  magma  that  remains  at  the  bot- 
tom may  still  be  rendered  useful,  by  pour- 
ing on  alcohol  in  the  manner  directed 
above  ;  but  care  must  be  taken,  to  add 
very  little  at  a  time. 

This  varnish  is  made  without  heat,  is 
very  clear  and  colourless,  may  be  applied 
with  equal  success  on  pasteboard,  wood, 
and  metals,  and  may  be  wovked  and  po- 
lished with  ease,  indeed  better  than  any 
known  varnish.  It  may  be  used  on 
paintings,  and  singularly  heightens  their 
beauty. 

Essential  Oil  Varnishes. 
The  high  price  of  most  of  the  essential 
oils  is  such  as  to  preclude  the  varnisher 
from  the  use  of  them ;  oil  of  lavender  is 
occasionally  employed,  but  the  usual  men- 
struum  is  oil  of  turpentine  The  purity 
of  this  latter  fluid  is  of  the  utmost  impor- 
tance; that  which  is  commonly  sold  at 
the  oil  and  colour  shops,  though  suffi* 
ciently  pure  for  oil  painting,  will  very 
rarely  answer  the  purpose  of  the  varnish- 
er,  who  if  he  wishes  to  save  himself  from 
much  mortification  and  disappointment 
will  apply  for  this  article  to  ehemists  and 
apothecaries,  where  it  may  be  procured 
(provided  it  be  particularly  so  ordered,) 
in  the  greatest  purity. 

Varnishes  with  oil  of  turpentine  and  the 
resins  are  somewhat  softer,  but  conside- 
rably tougher  than  those  prepared  with 
alcahol ;  hence  they  are  not  so  liable  to 
crack  and  scale  off.  They  are  principally 
used  for  varnishing  oil  paintings,  for  mix- 
ing up  colours  with,  and  for  lacquering. 
A  composiion  applicable  to  the  first  of 
these  purposes  is  the  following. 

8.  Take  of  pure  and  washed  mastich 
12  ounces,  and  of  pounded  glass  five 
ounces,  infuse  the  mixture  in  a  quart  of 
pure  oil  of  turpentine,  adding  at  intervals 
half  an  ounce  of  caniphoi  in  small  pieces : 
when  the  mastich  is  dissolved  add  to  the 
warmed  fluid  an  ounce  and  a  half  of  clear 
turpentine  previously  melted,  and  stir  the 
mixture  together  till  it  is  thoroughly  in» 
corporated. 

3  « 


VAK 


VAR 


Several  of  the  copal  varnishes  may  be 
also  arranged  under  this  section,  espe- 
cially those  that  are  best  fitted  for  var- 
nishing- articles  of  wood  and  pasteboard. 
Several  of  these  have  been  already  de- 
scribed under  the  article  Co  pal,  to  which 
we  refer  the  reader.  To  those  may  be 
added  the  following  very  simple  and  very 
efficacious  one. 

9  Take  from  3  to  4  ounces  of  copal, 
that  has  previously  been  liquefied  in  as 
gentle  a  heat  as  possible,  and  20  ounce 
measures  of  the  purest  oil  of  turpentine  ; 
put  this  latter  in  a  mattrass  set  in  boiling 
water,  and  add  the  pulverized  copal  in 
small  quantities  ajt  a  time,  in  proportion 
as  it  is  dissolved.  If  the  materials  are 
good,  and  the  process  well  conducted, 
somewhat  more  than  3  ounces  of  copal 
will  be  taken  up,  ard  the  liquid  will  be 
a  little  cloudy  :  by  standing  for  a  few  days 
it  will  become  clear,  and  should  then  be 
strained  through  cotton.  This  is  a  thick 
varnish,  and  will  generally  require  to  be 
diluted  with  a  little  warm  oil  of  turpen- 
tine before  it  can  be  used  ;  it  forms  a  very 
hard  and  durable  glazing,  which  will  dry 
in  summer  in  the  space  of  two  or  three 
days,  or  in  a  less  time  if  put  into  a  warm 
stove. 

Of  Fat  Oil  Varnishes. 

These  are  tougher  and  less  liable  to 
crack  than  the  preceding,  and  by  expo- 
sure to  a  proper  degree  of  heat,  may  be 
made  to  acquire  a  very  great  hardness  : 
they  are,  however,  without  the  assistance 
of  a  stove,  very  long  in  drying,  during 
winch  they  give  out  an  extremely  disa- 
greeable odour:  they  are  also,  for  the  most 
part,  highly  coloured,  and  are  therefore 
seldom  used  by  themselves,  but  mixed 
up  with  some  opake  colour.  The  mate- 
rials employed  in  the  composition  of  these 
varnishes,  with  the  exception  of  mere  co- 
louring substances,  are  the  following: — 
copal,  amber,  asphaltum,  drying  oil,  and 
oil  of  turpentine. 

The  most  colourless  of  the  fat  var- 
nishes is  thus  prepared. 

10.  Take  of  copal  liquefied,  according 
to  Tingry's  method,  and  finely  pulverised 
4  ounces,  of  drying  linseed  oil  and  oil  of 
turpentine,  each  10  ounces ;  put  the  whole 
into  a  mattrass,  and  apply  a  very  gentle 
heat  till  the  copal  is  dissolved :  this  being 
done,  let  the  varnish  stand  for  a  few  days 
to  clear,  and  afterwards  strain  it  through 
cotton.  This  forms  a  solid  and  nearly  co- 
lourless glazing,  and  dries  easily  at  the 
common  temperature. 

11.  Take  of  picked  copal  16  ounces, 
and  melt  it  in  a  clean  iron  pot  with  as 
gentle  a  heat  as  possible ;  when  its  fusion 


is  complete,  pour  in  3  ounces  of  drying 
linseed  oil,  boiling  hot,  and  incorporate 
the  ingredients  by  stirring ;  then  remove 
it  from  the  fire,  and  while  it  is  yet  warm, 
pour  in  a  pint  of  oil  of  turpentine,  also 
warm;  strain  the  varnish  before  it  gets 
cold,  through  a  piece  of  linen,  and  bottle 
it.  The  older  it  is  before  being  used  the 
better.  This  is  a  very  valuable  varnish, 
though  higher  coloured  than  the  pre- 
ceding; when  dried  carefully  in  a  stove 
it  becomes  very  hard.  Amber  varnish  is' 
reckoned  harder  than  copal  varnish,  on 
which  account  it  is  preferred  for  some 
works  ;  it  has  the  disadvantage,  however, 
of  being  much  deeper  coloured.  To  pre- 
pare this  varnish, 

12.  Take  of  amber  coarsely  pounded 
16  ounces,  and  melt  it  in  a  clean  iron  pot, 
then  add  to  it  2  ounces  of  melted  lac  and 
10  ounces  of  drying  oil  boiling  hot;  in- 
corporate the  whole  accurately  by  stir- 
ring, then  remove  it  from  the  fire,  and 
add  a  pint  of  warm  oil  of  turpentine. 

The  beautiful  black  varnish  used  by 
the  coach-makers  is  thus  prepared. 

13.  Take  of  amber  16  ounces,  and 
melt  it  in  a  clean  iron  pot,  then  add  to  it 
half  a  pint  of  drying  linseed  oil  boiling 
hot,  and  3  ounces  of  rosin,  and  the  same 
quantity  of  asphaltum,  each  in  fine  powr- 
der,  stir  the  materials  together  till  they 
are  thoroughly  melted  and  incorporated  ; 
then  remove  the  varnish  from  the  fire,  and 
add  to  it  a  pint  of  warm  oil  of  turpen- 
tine. 

The  above  oil  varnishes  are  intended  to 
dry  to  a  very  hard  consistence ;  those, 
however,  that  are  employed  for  making 
silk,  and  linen,  water,  and  air  tight,  are  re- 
quired to  be  tough,  without  any  degree  of 
hardness.  A  varnish  of  this  kind,  which 
was  first  applied  to  balloons,  is  thus  com- 
posed. 

Recipe  for  an  elastic  and  permanent  Var- 
nish for  Hats  or  Helmets  of  Felt,  Gai- 
ters, or  other  Parts  of  Dress  in  Lea- 
ther, as  Hoots  and  Shoes,  and  which 
may  be  also  employed  with  success  in 
'varnishing  Cloth  and  Linen. 

First  Operation. — It  is  necessary,  in  the 
first  place,  to  free  the  hats,  or  other  arti- 
cles of  felt,  from  all  the  gum  which  they 
may  contain.  This  may  be  easily  effected 
by  washing  them  in  warm  water,  and  af- 
terwards pressing  them.  Before  they  are 
perfectly  dry,  they  must  be  placed  on 
moulds  in  order  that  they  may  be  pre- 
served in  their  proper  shape,  and  be 
without  wrinkles — a  very  essential  requi- 
site.  New  leather,  as  well  as  old,  must 


VAR 


YAK 


be  scraped  in  order  to  clear  its  superfi- 
cies from  the  wax  or  grease,  with  which 
it  is  impregnated.  Colophony,  or  resin 
in  powder,  laid  upon  a  coarse  brush,  will 
remove  the  grease  perfectly  well. 

Second  Operation. — All  felt  hats  have  a 
kind  of  down  or  nap,  of  which  they  must 
be  cleared,  when  dry,  by  means  of  pu- 
mice stone ;  and  every  part  of  the  hat 
where  the  varnish  is  to  be  applied  must 
be  smoothed  in  this  manner.  Leather 
must  be  smoothed  in  the  same  manner  al- 
so, to  remove  all  inequalities,  and  even 
the  marks  of  the  scraper. 

The  same  method  must  be  pursued 
with  cloths  or  linens. 

Third  Operation. — The  down  being1  re- 
moved in  the  manner  above  described,  a 
coat  of  the  black  varnish,  to  be  after- 
wards  mentioned,  must  be  laid  on  the  ar- 
ticles to  be  varnished.  They  must  be  al- 
lowed to  dry  well  upon  their  moulds, 
that  they  may  not  assume  any  wrinkles, 
which  prevent  the  proper  distribution  of 
the  varnish. 

Fourth  Operation. — This  first  coat  of 
varnish  being"  perfectly  dry,  the  pumice 
stone  must  be  again  resorted  to,  in  order 
to  remove  any  small  inequalities  which 
may  remain. 

Fifth  Operation. — When  the  air  is  dry 
and  warm,  a  second  coat  of  the  black 
varnish  must  be  applied,  and  also  polish- 
ed with  the  pumice  stone. 

Sixth  Operation. — The  finishing-  hand 
must  now  be  put  to  the  article  by  laying 
on  the  varnish  to  be  afterwards  describ- 
ed, taking  care  to  employ  for  this  pur- 
pose a  small  and  compact  pencil,  in  order 
to  spread  the  varnish  uniformly  and 
equally. 

When  the  first  coat  of  varnish  is  well 
dried,  it  must  be  sprinkled  with  pumice 
stone  reduced  to  fine  powder,  and  then 
rubbed  all  over  with  a  wet  sponge,  or  a 
piece  of  fine  linen  rag  also  wetted,  in  or- 
der to  render  the  varnish  perfectly 
smooth ;  or  in  place  of  pumice  stone, 
with  tripoli,  soaked  in  oil  and  rubbed  with 
the  palm  of  the  hand.  As  to  the  second 
.and  last  coat  of  varnish,  it  must  be  po- 
lished when  well  dried,  by  sprinkling'  it 
with  starch  and  rubbing  it  with  a  piece 
of  old  linen  rag,  which  will  give  it  a  very 
fine  lustre. 

In  the  event  of  the  varnish  being  tar- 
nished, or  losing  its  lustre  by  long  usage, 
in  order  to  restore  it,  place  the  articles  of 
felt  or  leather  in  boiling  water  for  a  mi- 
nute, then  let  them  dry  thoroughly, 
sprinkle  them  with  starch,  and  rub  them 
with  a  piece  of  dry  linen,  and  they  will 
resume  their  former  lustre. 


Preparation  of  Linseed  Oil,  under  the  dr> 
nomination  of  Oil  af  Marmitc. 
Take  Linseed  oil    15  pounds 
Umber  4  ounces 

Red  Lead  1  pound  8  ounces 
White  Lead  2  pounds  4ounces 
Put  the  whole  into  a  pot  placed  upon  a 
coal  fire ;  boil  it  for  thirty-six  or  forty  mi- 
nutes; stir  it  from  time  to  time  with  a 
wooden  spatula ;  and  care  must  be  taken 
that  it  is  neither  too  little  boiled,  nor  vis- 
cous, from  being  too  much  so. 

Upon  taking  the  pot  off  the  fire,  throw 
in  a  piece  of  bread,  both  crust  and  crumb, 
of  the  size  of  a  small  loaf.  Cover  it,  and 
let  it  cool  for  twenty-four  hours.  The  oil 
thus  prepared  is  made  iuj  of  for  various 
purposes. 

Composition  of  the  Black  Varnish. 

1.  Take  of  black  umber  two  pounds 
thirteen  ounces ;  cut  it  into  small  pieces, 
and  place  them  in  a  frying  pan  upon  a 
very  brisk  fire,  and  roast  it  like  coffee  for 
about  three  quarters  of  an  hour  ;  bruise 
it  afterwards  upon  a  marble-slab,  by  mix- 
ing it  in  the  manner  of  painters,  with  a 
little  boiled  linseed  oil,  and  keep  it  in  a 
stone  pot. 

2.  Take  three  pounds  of  verdigrise; 
reduce  it  to  an  impalpable  powder ;  mix 
it  with  the  boiled  linseed  oil ;  then  put  it 
into  the  stone  pot  which  contains  the  um- 
ber. 

3.  Take  of  lamp-black  one  pound,  mix 
it  also  with  boiled  linseed  oil,  and  after 
putting  it  also,  into  the  stone  pot,  blend 
the  whole  well  together. 

This  is  the  mixture  made  use  of  to 
varnish  articles  of  felt,  cloth,  or  leather, 
observing  that  when  leather  is  to  be  var- 
nished, it  is  essential  to  give  it  previously 
two  or  three,  and  sometimes  even  six, 
coats  of  linseed  oil ;  it  must  be  well  dri- 
ed each  time,  in  order  to  extract  the 
grease  from  the  leather,  wax,  or  fish  oil, 
in  order  that  the  varnish  may  incorporate 
with  the  leather  more  easily.  This  pre- 
caution must  be  made  use  of  with  soft 
boots,  when  placed  upon  moulds  or  boot- 
trees  ;  and,  without  even  taking  them  off, 
as  many  coats  of  varnish  may  be  laid  on 
as  necessary. 

Method  of  preparing  the  Varnish. 
Take  of  Prussian  blue    12  ounces 
Indigo  12 
Bruise  these  two  separately  upon  a  mar- 
ble slab ;  mix  them  up  with  a  little  oil, 
and  put  them  in  a  pot  by  themselves. 
Afterwards  take  of  gum  copal  8  ounces 
Prepared  nut  oil  5 
Spirit  of  turpentine  14 


VAR 


VAIi 


Put  the  gum-copal,  bruised  in  a  matrass 
with  a  large  neck,  upon  a  strong  fire,  but 
not  flaming-,  taking  care  to  stir  it  often, 
and  to  keep  it  uncovered  We  know  that 
the  gum  is  totally  dissolved  when  the 
smoke  has  entirely  abated  in  the  matrass  t 
pour  into  it,  by  little  and  little,  prepared 
nut  oil,  stirring  it  in  order  to  incorporate 
the  whole  completely.  Afterwards,  and 
in  the  same  manner,  the  spirit  of  turpen- 
tine is  poured  in,  and  the  mixture  is  then 
taken  from  the  fire,  filtered,  and  cooled  ; 
it  is  then  made  use  of  to  grind  with  the 
Prussian  blue  and  indigo  in  small  quanti- 
ties at  a  time,  and  the  whole  is  well  mix- 
ed together. 

This  mixture)  forms  the  fine  varnish  for 
the  purposes  indicated. 

14.  Take  of  the  best  oil  of  turpentine 
o  ounces,  and  of  Indian  rubber  in  slips  a 
third  of  an  ounce ;  put  the  whole  in  a 
close  corked  bottle,  and  keep  it  at  the 
usual  temperature  for  three  or  four  days, 
in  which  time  the  Indian  rubber  will  for  the 
most  part  be  dissolved,  forming  a  tena- 
cious thick  fluid ;  pour  this  into  a  pint  of 
drying  linseed  oil,  and  heat  the  mixture 
for  a  few  minutes  nearly  to  boiling,  then 
take  it  from  the  fire  and  strain  it  while 
warm  through  a  piece  of  linen.  This  is 
a  very  effectual  varnish,  but  it  is  long  in 
drying.  The  following  therefore  is  to  be 
preferred. 

15  Take  of  very  drying  linseed  oil,  hall' 
a  pint,  and  of  birdlime  1  pound,  put  the 
mixture  in  an  iron  'pot,  and  heat  it  nearly 
to  boiling,  till  the  birdlime  ceases  to  crac- 
kle, then  pour  in  2$  pints  more  of  drying 
oil,  and  boil  it  for  about  an  hour  with 
constant  stirring,  taking  care  that  it  does 
not  boil  over.  When  it  has  acquired  so 
much  tenacity  that  a  little,rubbed  between 
two  knife  blades,  will  draw  out  into 
threads  on  the  separation  of  the  blades 
from  each  other,  it  may  be  removed  from 
the  fire,  and  well  mixed  with  a  quart  of 
oil  of  turpentine,  and  then  strained  and 
bottled.  In  order  to  apply  it,  the  silk  or 
linen  must  be  quite  dry  and  the  varnish 
lukewarm  ;  a  thin  coat  is  to  be  first  laid 
on  one  side,  and  about  iwelve  hours  after, 
two  other  coats  should  belaid  on,  one  on 
each  side,  and  in  twenty -four  hours  after, 
the  stuff  will  be  dry  enough  to  be  used. 

The  following  varnishes  may  be  also 
noticed. 

Black  Vimish  for  Coaches  and  Iron-Work 
This  varnish  is  composed  of  asphaltum, 
resin,  and  amber,  melted  separately,  and 
afterwards  mixed ;  the  oil  is  then  added, 
and  afterwards  the  turpentine,  as  direct- 
ed above.   The  usual  proportions  are, 


twelve  ounces  of  amber,  two  of  resin* 
two  of  asphaltum,  six  of  oil,  and  twelve 
of  turpentine. 

A  Varnish  for  rendering  Silk  water  ancl 
air  tight. 

To  render  the  linseed-oil  drying,  boil 
it  with  two  ounces  of  sugar  of  lead,  and 
three  ounces  of  litharge,  for  every  pint 
of  oil,  till  the  oil  has  dissolved  them  j  then 
put  a  pound  of  bird-lime,  and  half  a  pint 
of  the  drying-oil,  into  a  pot  of  iron  or 
copper,  holding  about  a  gallon  ;  and  let  it 
boil  gently  over  a  slow  charcoal  fire,  till 
the  bird-lime  ceases  to  crackle  ;  then  pour 
upon  it  two  pints  and  a  half  of  drying-oil, 
and  boil  it  for  an  hour  longer,  stirring  it 
often  with  an  iron  or  wooden  spatula.  As 
the  varnish,  in  boiling,  swells  much,  the 
pot  should  be  removed  from  the  fire,  and 
replaced  when  the  varnish  subsides. 
While  it  is  boiling,  it  should  -be  occasion- 
ally examined,  in  order  to  determine  whe- 
ther it  has  boiled  enough.  For  this  pur- 
pose, take  some  of  it  upon  the  blade  of  a 
large  knife,  and  after  rubbing  the  blade 
of  another  knife  upon  it,  separate  the 
I  knives;  and  when,  on  their  separation, 
the  varnish  begins  to  form  threads  be- 
tween the  two  knives,  it  has  boiled 
enough,  and  should  be  removed  from  the 
fire-  When  it  is  almost  cold,  add  about 
an  equal  quantity  of  spirits  of  turpen- 
tine ;  mix  both  well  together,  and  let  the 
mass  rest  till  the  next  day ;  then,  having 
warmed  it  a  little,  strain  and  bottle  it  If 
it  is  too  thick,  add  spirits  of  turpentine. 
This  varnish  should  be  laid  upon  the  stuff 
when  perfectly  dry,  in  a  lukewarm  state ; 
a  thin  coat  of  it  upon  one  side,  and,  about 
12  hours  after,  two  other  coats  should  be 
laid  on,  one  on  each  side;  and  in  24 
hours  the  silk  may  be  used. 

Jlr.  Blanchard's  Varnish  for  Air-balloons. 

Dissolve  elastic  gum  (Indian-rubber) 
cut  small,  in  five  times  its  weight  of  spi- 
rits of  turpentine,  by  keeping  them  some 
days  together ;  then  boil  one  ounce  of 
this  solution  in  eight  ounces  of  drying 
linseed-oil  for  a  few  minutes,  and  strain 
it    Use  it  warm. 

A  Varnish  for  Wainscot,  Cane  Chairs, 

Ufa 

Dissolve  in  a  quart  of  spirits  of  wine, 
eight  ounces  of  gum-sandarach,  two 
ounces  of  seed-lac,  and  four  ounces  of 
•  esin  ;  then  add  six  ounces  of  Venice-tur- 
pentine. If  the  varnish  is  to  produce  a 
red  colour,  more  of  the  lac  and  less  of 
sandarach  should  be  used,  and  a  little 
dragon's-blood  should  be  added.  This 
varnish  is  Very  strong. 


VAR 


VAR 


A  Varnish  for  Toilet-Boxes,  Cases,  Fans, 
life. 

Dissolve  two  ounces  of  gum-mastich, 
rind  eight  ounces  of  gum -sandarach,  in  a 
quart  of  alcohol ;  then  add  four  ounces 
of  Venice  turpentine. 

A  Varnish  fur  Violins,  and  other  Musical 
Instruments. 
Ptit  four  ounces  of  gum-sandarach, 
two  ounces  of  lac,  two  ounces  of  gum- 
mastich,  an  ounce  of  gum-elemi,  into  a 
quart  of  alcohol,  and  hang  them  over  a 
slow  fire  till  they  are  dissolved,  then  add 
two  ounces  of  turpentine. 

Varnish  for  employ hig  Vermilion  for  paint- 
ing Equipages. 
Dissolve  in  a  quart  of  alcohol  six 
ounces  of  sandarach,  three  ounce  of  gum- 
lac,  and  four  ounces  of  resin  ;  afterwards 
add  six  ounces  of  the  cheapest  kind  of 
turpentine ;  mix  it  with  a  proper  quanti- 
ty of  vermilion  when  it  is  to  be  used. 

White  Varnish  for  Clock  Faces,  lD"c. 

Take  of  spirits  of  wine  (highly  rectifi- 
ed) one  pint,  which  divide  into  four  parts  ; 
then  mix  one  part  with  half  an  ounce  of 
gum-mastich,  in  a  phial  by  itself;  one 
part  of  spirits,  and  half  an  ounce  of  gum- 
sandarach  in  another  phial ;  one  part  of 
spirits,  and  half  an  ounce  of  the  whitest 
parts  of  gum-benjamin.  Then  mix  and 
temper  them  to  your  mind.  It  would  not 
be  amiss  to  add  a  little  bit  of  white  resin, 
or  clear  Venice-turpentine,  in  the  mastich 
bottle  ;  it  will  assist  in  giving  a  gloss.  If 
your  varnish  prove  too  strong  and  thick, 
add  spirits  of  wine  only  ;  if  too  hard, 
some  dissolved  mastich  ;  if  too  soft,  some 
sandarach  or  benjamin. 

Varnishes  should  be  carefully  kept  from 
dust,  and  in  very  clean  vessels  :  they 
should  be  laid  as  thin  and  even  as  possi- 
ble with  a  large  flat  brush,  taking  care  to 
lay  the  strokes  all  one  way.  A  warm 
room  is  best  for  varnishing  in,  as  cold 
chills  the  varnish,  and  prevents  it  from 
laying  even. 

Varnishes  are  polished  with  pumice- 
stone  and  tripoli.  The  pumice-stone  must 
be  reduced  to  a  very  fine  powder,  and  put 
upon  a  piece  of  serge  moistened  with  wa- 
ter ;  with  this  the  varnished  substance  is 
to  be  rubbed  equally  and  lightly.  The 
tripoli  must  also  be  reduced  to  a  fine 
powder,  and  put  upon  a  clean  woollen 
cloth  moistened  with  olive-oil,  with  which 
the  polishing  is  to  be  performed.  The  var- 
nish is  then  to  be  wiped  with  soft  linen, 
and,  when  quite  dry,  cleaned  with  starch, 
or  Spanish-white,  and  rubbed  with  the 
palm  of  the  hand,  or  with  a  linen  cloth. 


Of  Lacquers. 
A  lacquer  is  a  transparent  varnish  ap- 
plied to  i he  surface  of  metals,  both  for  the 
purpose  of  protecting  them  from  the  ac- 
tion of  air  and  moisture,  and  lor  heighten- 
ing their  colour,  and  bringing  it  nearer  to 
that  of  gold.  The  metals  that  are  com- 
monly lacquered  are  brass  and  tin.  The 
following  are  some  of  the  best  varnishes 
for  the  purpose. 

17.  Take  of  turmeric  pulverized,  one 
ounce,  and  of  saffron  and  annotto  each  2 
drachms  ;  infuse  thern  at  a  moderate  tem- 
perature for  a  week  or  more  in  a  pint  of 
rectified  alcohol  :  separate  the  yellow 
tincture  thus  obtained,  by  straining 
through  a  piece  of  clean  linen,  and  add 
to  the  clear  liquor  three  ounces  of  good 
seed  lac :  let  the  materials  digest  toge- 
ther for  some  days  in  a  bottle,  with  fre- 
quent shaking,  and  then  strain  oil'  the 
clear  part,  which  is  the  lacquer.  If  the 
piece  of  brass  to  which  it  is  to  be  applied 
is  large,  as  a  lock  for  example,  it  is  to  be 
warmed,  and  the  lacquer  also  warm  is  to 
be  spread  on  with  a  brush  ;  if  the  arti- 
cles are  small  they  are  to  be  made  up  into 
packets,  then  warmed,  and  afterwards 
dipped  into  the  varnish. 

Another  lacquer  for  brass  still  cheaper 
than  the  foregoing,  and  nearly  as  good,  is 
made  by  substituting  half  a  drachm  of 
the  best  dragon's  blood  instead  of  the 
saffron  and  annotto. 

The  following  varnish  may  be  applied 
to  lamps,  and  other  articles  of  tinned 
ware,  in  order  to  make  them  resemble 
brass. 

18.  Take  of  turmeric  one  ounce,  and 
of  dragon's  blood  two  drachms;  infuse 
the  ingredients  in  a  pint  of  alcohol,  and 
when  the  tincture  is  completed,  strain  it 
through  a  piece  of  clean  linen,  and  add  to 
the  ciear  liquor  three  ounces  of  seed  lac  ; 
in  a  few  days  the  solution  will  be  com- 
pleted, after  which  the  varnish  is  to  be 
strained,  and  is  then  fit  for  use. 

One  more  lacquer  remains  to  be  men- 
tioned, namely,  that  which  is  employed  in 
the  preparation  of  gilt  leather  as  it  is 
called.  The  appearance  of  gilding  is  pro- 
duced on  leather  by  fixing  upon  it,  by 
means  of  strong  size,  very  highly  bur- 
nished tinfoil  or  silver  leaf,  and  then  coat 
ing  the  polished  surface  over  with  the 
following  varnish. 

19.  Take  of  fine  white  resin  4 h  pounds, 
of  common  resin  the  same  quantity,  of 
gum  sandarach  2h  pounds,  and  of  com- 
mon aloes  2  pounds :  melt  the  whole 
over  a  gentle  lire,  stirring  them  well  at 
the  same  time  with  an  iron  spatula:  when 
the  fusion  is  complete  add  by  degrees  7 
pints  of  linseed  oil,  and  make  the  whol** 


VEG 


VEG 


boil  for  six  or  seven  hours,  stirring-  it 
carefully  all  the  time.  When  the  varnish 
begins  to  get  ropy,  stir  in  half  an  ounce 
of  red  lead  finely  pulverized :  as  soon  as 
this  latter  is  completely  dissolved,  re- 
move the  varnish  from  the  fire  and  strain 
it  while  Warm  through  a  linen  or  flannel 
bag. 

VEG-ALKALT.  The  name  given  by 
Dr.  Pearson,  to  Potash. 

VEGETABLE  ALKALI,  in  contra- 
distinction of  mineral  alkali,  a  name  given 
to  potash.    See  Po  tash. 

VEGETABLE  KINGDOM.  In  the  mi- 
neral kingdom  little  of  chemical  operation 
takes  place,  wherein  the  peculiar  locality 
or  disposition  of  the  principles,  which  act 
upon  each  other,  appears  to  have  any  con- 
siderable effect.  The  principles,  for  the 
most  partjsimple,  act  upon  each  other  by 
virtue  of  their  respective  attractions  ;  if 
beat  be  developed,  it  is  for  the  most  part 
speedily  conducted  away;  it  elastic  pro- 
ducts be  extricated,  ihey  in  general  make 
their  escape ;  in  a  word,  we  seldom  per- 
ceive in  the  operations  in  the  mineral 
kingdom  any  arrangement,  which  at  all 
resembles  the  artificial  dispositions  of  the 
chemist. 

But  in  the  animal  and  vegetable  king- 
doms it  is  far  otherwise.  In  the  former 
of  these,  bodies  are  regularly  changed  by 
mechanical  division,  by  digestion,  and  the 
application  of  peculiar  solvents,  in  a  tem- 
perature exceeding  that  ofthe  atmosphere, 
and  the  whole  of  the  effects  are  assisted, 
modified  and  kept  up  by  an  apparatus  for 
admitting  the  air  ofthe  atmosphere.  The 
subjects  of  the  vegetable  kingdom  pos- 
sess, undoubtedly  a  structure  less  elabo- 
rate. They  exhibit  much  less  of  those 
energies,  which  are  said  to  be  spontane- 
ous. The  form  of  their  vessels  is  much 
simpler,  and,  as  far  as  we  can  perceive, 
their  action  is  obedient  to  the  changes  of 
the  atmosphere  in  quality  and  moisture, 
the  mechanical  action  of  winds,  the  tem- 
perature ofthe  weather,  and  the  influence 
of  light.  In  these  organized  beings,  the 
chemist  discovers  principles  of  a  more 
compounded  nature  than  any  which  can 
be  obtained  from  the  mineral  kingdom. 
These  do  not  previously  exist  in  the  earth, 
and  must  therefore  be  results  of  vegeta- 
ble life. 

The  most  obvious  difference  between 
vegetables  and  animals,  is,  that  the  latter 
are  in  general,  capable  of  conveying  them- 
selves from  place  to  place ;  whereas  ve- 
getables, being  fixed  in  the  same  place, 
absorb  by  means  of  their  roots  and  leaves, 
such  support  as  is  within  their  reach. — 
This  appears  on  the  whole,  to  consist  of 
air  and  water.   The  greatest  part  of  the 


support  of  animals,  are  the  products  al- 
ready elaborated  in  the  vegetable  king- 
dom. The  products  of  these  two  king- 
doms in  the  hands  of  the  chemist  are  re- 
markably different,  though  perhaps  not 
exclusively  so.  One  of  the  most  distinc- 
tive characters,  seems  to  be  the  presence 
of  nitrogen  or  azotic  gas,  which  may  be 
extricated  from  animal  substances,  by  the 
application  of  nitric  acid,  and  enters  into 
the  composition  of  the  ammonia,  afforded 
by  destructive  distillation.  It  was  long 
supposed,  that  ammonia  was  exclusively 
the  product  of  the  animal  kingdom,  but  it 
is  now  well  known,  that  certain  plants 
likewise  afford  it. 

When  it  is  considered,  that  by  far  the 
greater  pan  of  every  organized  substance, 
is  capable  of  assuming  the  elastic  form, 
and  being  volatilized  by  heat;  that  the  pro- 
!  ducts  during  life,  are  brought  into  combi- 
|  nation  by  slow  and  long-continued  pro- 
cesses, and  are  kept  separate  from  each 
other,  in  the  vessels  of  the  plant  or  ani- 
mal ;  that  these  combinations  are  liable 
to  be  altered  by  the  destruction  of  those 
vessels,  as  well  as  by  every  notable  change 
of  temperature,  it  will  not  nppear  sur- 
prising, that  the  chemical  analysis  of 
plants,  should  be  in  a  very  imperfect 
state. 

The  ancient  chemists  had  no  other  me- 
thods of  examining  plants,  than  by  de- 
structive distillation,  and  the  successive 
application  of  water  and  alcohol.  They 
had  no  method  of  examining,  the  elastic 
products  of  their  distillations.  This  me- 
thod is  on  every  account  of  little  value. 
For  the  new  combinations  produced  by 
the  heat,  exhibit  products  nearly  similar 
from  substances,  originally  very  different. 
The  other  method  by  the  application  of 
solvents,  is  somewhat  more  accurate,  and 
has  besides  affoi  ded  products  of  consider- 
able utility  in  the  arts,  and  for  the  ordi- 
nary purposes  of  life. 

In  the  structure  of  vegetables,  we  ob- 
serve the  external  covering  or  bark,  the 
ligneous  or  woody  matter,  the  vessels  or 
tubes,  and  certain  glandular  or  knotty 
parts.  The  comparative  anatomy,  and 
immediate  uses  of  these  parts,  form  an 
object  of  interesting  research,  but  less 
immediately  within  the  province  of  a  che- 
mical work. 

The  nutrition  or  support  of  plants  ap- 
pears to  require  water,  earth,  light,  and 
air.  There  are  various  experiments, which 
have  been  instituted  to  show,  that  water 
is  the  only  aliment,  which  the  root  draws 
from  the  earth.  Van  llelmont  planted  a 
willow,  weighing  fifty  pounds,  in  a  cer- 
tain quantity  of  earth  covered  \yith  sheet 
lead  .-  he  watered  it  for  five  years  with 


VEG 


VEG 


distilled  water ;  and  at  the  end  of  that 
time,  the  tree  weighed  169  pounds  three 
ounces,  and  the  earth  in  which  it  had  ve- 
getated, was  found  to  have  suffered  a  loss 
'of  no  more  than  three  ounces.  Boyle  re- 
peated the  same  experiment  upon  a  plant, 
which  at  the  end  of  two  years,  weighing 
14  pounds  more,  without  the  earth  in 
which  it  had  vegetated,  having  lost  any 
perceptible  portion  of  its  weight. 

Messrs.  Duhamel  and  Bonnet  support- 
ed plants  with  moss,  and  fed  them  with 
mere  water:  they  observed,  that  the  ve- 
getation was  of  the  most  vigorous  kind  ; 
and  the  naturalist  of  Geneva,  observes, 
that  the  flowers  were  more  odoriferous, 
and  the  fruit  of  a  higher  flavour.  Care 
was  taken  to  change  the  supports,  before 
they  could  suffer  any  alteration.  Mr. 
Tillet  has  likewise  raised  plants,  more 
especially  of  the  gramineous  kind,  in  a 
similar  manner  ;  with  this  difference  only, 
that  his  supports  were  pounded  glass,  or 
quartz  in  powder.  Hales  has  observed, 
that  a  plant,  which  weighed  three  pounds, 
gained  three  ounces  after  a  heavy  dew. 
Do  we  not  every  day  observe,  hyacinths 
and  other  bulbous  plants,  as  well  as  gra- 
mineous plants,  raised  in  saucers  or  bot- 
tles containing  mere  water  ?  And  Bracan- 
not  has  lately  found  mustard  seed  to  ger- 
minate, grow,  and  produce  plants,  that 
came  to  maturity,  flowered,  and  ripened 
their  seed,  in  litharge,  flowers  of  sulphur, 
and  very  small  unglazed  shot.  The  last 
appeared  least  favourable  to  the  growth 
of  the  plants,  apparently  because  their 
roots  could  not  penetrate  between  it  so 
easily. 

All  plants  do  not  demand  the  same 
quantity  of  water  ;  and  nature  has  varied 
the  organs  of  the  several  individuals,  con- 
formable to  the  necessity  of  their  being 
supplied  with  this  food.  Plants  which 
transpire  litttle,  such  as  the  mosses  and 
the  lichens,  have  no  need  of  a  consider- 
able quantity  of  this  fluid  ;  and  accord- 
ingly they  are  fixed  upon  dry  rocks,  and 
have  scarcely  any  roots ;  but  plants  which 
require  a  larger  quantity,  have  roots 
which  extend  to  a  great  distance,  and  ab- 
sorb humidity  throughout  their  whole 
surface. 

The  leaves  of  plants  have  likewise  the 
property  of  absorbing  water,  and  of  ex- 
tracting from  the  atmosphere  the  same 
principle,  which  the  root  draws  from  the 
earth.  But  plants  which  live  in  the  water, 
and  as  it  were  swim  in  the  element,  which 
serves  them  for  food,  have  no  need  of 
roots  ;  they  receive  the  fluid  at  all  their 
pores  :  and  we  accordingly  find  that  the 
fucus,  and  the  ulva,  &c,  have  no  roots 
whatever, 


The  purer  the  water,  the  more  saluta- 
ry it  is  to  plants.  Mr  Duhamel  has  drawn, 
this  consequei.ee  from  a  series  of  well- 
made  experiments,  by  which  he  has  prov- 
ed, that  water  impregnated  with  suits  is 
fatal  to  vegetation  Hales  caused  them 
to  absorb  various  fluids  by  making  inci- 
sions in  their  roots,  and  plunging  them 
into  alcohol,  mercury,  and  various  saline 
solutions  ;  but  he  was  convinced,  that  all 
these  were  poisons  to  the  vegetables.  Be- 
sides, if  these  salts  were  favourable  to  the 
plants,  they  would  be  again  found  in  the 
individual,  which  had  been  watered  with 
a  solution  of  them  ;  whereas  Messrs. 
Thouvenel  and  Cornette  have  proved, 
that  these  salts  do  hot  pass  into  the  vege- 
table. We  must  nevertheless  except  the 
marine  plants,  because  the  sea-salt  of 
which  they  have  need,  is  decomposed  in 
them  ;  and  produces  a  principle,  which 
appears  necessary  to  their  existence,  since 
they  languish  without  it. 

Though  it  is  proved,  that  pure  water 
is  more  proper  for  vegetation  than  water 
charged  with  salts,  it  must  not  on  this  ac- 
count be  concluded,  that  water  cannot  be 
disposed  in  a  more  favourable  manner  to 
the  developement  of  vegetables,  by  charg- 
ing with  the  remains  of  vegetable  and 
animal  decomposition.  If,  for  example, 
the  water  be  loaded  with  principles  dis- 
engaged by  fermentation  or  putrefaction, 
the  plant  then  receives  juices  already  as- 
similated to  ks  nature,  and  these  prepar- 
ed aliments  must  hasten  its  growth.  Inde- 
pendent of  those  juices  already  formed, 
the  nitrogen  gas,  which  constitutes  one 
of  the  nutritive  principles  of  plants,  and 
is  abundantly  afforded  by  the  alteration 
of  vegetables  and  animals,  must  facilitate 
their  developement.  A  plant  supported 
by  the  remains  of  vegetables  and  animals, 
is  in  the  same  situation  as  an  animal  fed 
on  milk  only ;  its  organs  have  less  diffi- 
culty in  elaborating  this  drink,  than  that 
which  has  not  yet  been  animalized.  W 

From  the  preceding  circumstances  it 
appears  that  the  influence  of  the  earth  in 
vegetation,  is  almost  totally  confined  to 
the  conveyance  of  water,  and  probably  the 
elastic  products  from  putrefying  substan- 
ces to  the  plant. 

Vegetables  cannot  live  without  air.  

From  the  experiments  of  Priestley,  Ingen- 
houtz  and  Sennebier,  it  is  ascertained, 
that  plants  absorb  the  azotic  part  of  the 
atmosphere  ;  and  this  principle  appears  to 
be  the  cause  of  the  fertility,  which  arises 
from  the  use  of  putrefying  matters  in  the 
form  of  manure.  The  carbonic  acid  is 
likewise  absorbed  by  vegetables,  when  its 
quantity  is  small.  If  in  large  quantity,  it 
is  fatal  to  them. 


VEG 


TEG 


Chaptal  has  observed,  that  carbonic 
acid  predominates  in  the  fungus,  and  oth  - 
er subterraneous  plants.  But  by  causing 
these  vegetables,  fr  gether  with  the  body 
upon  which  they  were  fixed,  to  pass,  by 
imperceptible  gradations,  from  an  abso- 
lute darkness  into  the  light,  the  acid  very 
nearly  disappeared ;  tlv  vegetable  fibres 
being  proportionally  increased,  at  the 
same  time  that  the  resin  and  colouring 
principles  were  developed,  which  he  as- 
cribes to  the  oxygen  of  the  same  acid. — 
Sennebier  has  observed, -that  the  plants 
which  he  was  watered  with  water,  im- 
pregnated with  carbonic  acid,  transpired 
an  extraordinary  quantity  of  oxygen,which 
likewise  indicates  a  decomposition  of  the 
acid. 

Light  is  almost  absolutely  necessary  to 
plants.  In  the  dark  they  grow  pale,  lan- 
guish and  die.  The  tendency  of  plants 
toward  the  light,  is  remarkably  seen  in 
such  vegetation,  if  it  is  effected  in  a 
chamber  or  place  where  the  light  is  ad- 
mitted on  one  side  ;  for  the  plant  never 
fails  to  grow  in  that  direction.  Whether 
the  matter  of  light  be  condensed  into  the 
substance  of  plants,  or  whether  it  acts 
merely  as  a  stimulous  or  agent,  without 
which  the  other  requisite  chemical  pro- 
cesses cannot  be  effected,  is  uncertain. 

It  is  ascertained,  that  the  processes  in 
plants  serve,  like  those  in  animals,  to  pro- 
duce a  more  equable  temperature,  which 
is  for  the  most  pait  above  that  of  the 'at- 
mosphere. Dr.  Hunter,  quoted  by  Chap- 
tal, observed  by  keeping  a  thermometer 
plunged  in  a  hole  made  in  a  sound  tree, 
that  it  constantly  indicated  a  temperature 
several  degrees  above  that  of  the  atmos- 
phere, when  it  was  below  the  fifty-sixth 
division  of  Fahrenheit ;  whereas  the  ve- 
getable beat,  in  hotter  weather,  was  al- 
ways several  degrees  below  that  of  the 
atmosphere.  The  same  philosopher  has 
likewise  observed,  that  the  sap,  which  out 
of  the  tree,  would  freeze  at  32°  Fah.  did 
not  freeze  in  the  tree  unless  the  cold  were 
augmented  15°  more. 

The  vegetable  heat  may  increase  or  di- 
minish by  several  causes,  of  the  nature  of 
disease;  and  it  may  even  become  per- 
ceptible to  the  touch  in  very  coid  weather, 
according  to  Buffon. 

The  principles  of  which  vegetables  are 
composed,  if  we  pursue  their  analysis 
hs  far  as  our  means  have  hitherto  allow- 
ed, are  chiefly  carbon,  hydrogen,  and  ox- 
ygen. 

The  number  of  principles,  both  simple 
and  compound  [possessed  of  distinct  cha- 
racters] which  have  been  extracted  from 
vegetables,  has  been  much  increased  by 
the  investigation  of  modern  chemists.  Of 


j  these  principles  we  shall  here  give  an  enu- 
meration from  the  works  of  Dr.Thompson, 
a  late  celebrated  writer  on  the  subject,  of 
their  chemical  characters  ;  referring  the 
reader  for  a  further  account  of  such  of 
them  as  come  within  the  nature  of  our 
work,  to  their  place  in  alphabetical  order. 

1-  Sugar.  Crystallizes.  Soluble  in  wa- 
ter and  alcohol.  Taste  sweet.  Soluble 
in  nitric  acid,  and  yields  oxalic  acid. 

2.  Sarcocol.  Does  not  crystallize.  Solu- 
ble in  water  and  alcohol.  Taste  bitter 
sweet.  Soluble  in  nitric  acid,  and  yields 
oxalic  acid. 

3.  Aspciragtn.  Crystallizes.  Taste  cool 
ing  and  nauseous.  Soluble  in  hot  water 
Insoluble  in  alcohol.  Soluble  in  nitric 
acid,  and  converted  into  bitter  principle 
and  artificial  tannin. 

4.  Gum.  Does  not  crystallize.  Taste 
insipid.  Soluble  in  water,  and  forms  mu- 
cilage Insoluble  in  alcohol.  Precpitat* 
ed  by  siheated  potash.  Soluble  in  nitric 
acid,  and  forms  mucous  and  oxalic  acids. 

5.  Uhnin.  Does  not  crystallize-  Taste 
insipid.  Soluble  in  water,  and  does  not 
form  mucilage.  Precipitated  by  nitric  and 
oxymuriatic  acids,  in  the  state  of  resin. 
Insoluble  in  alcohol. 

6.  Inulin.  A  white  powder.  Insoluble 
in  cold  water.  Soluble  in  boiling  water  ; 
but  precipitates  unaltered  after  the  so- 
lution cools.  Insoluble  in  alcohol.  So- 
luble in  nitric  acid,  and  vields  oxalic 
acid. 

7.  Starch.  A  white  powder.  Taste  in- 
sipid. Insoluble  in  cold  water.  Soluble 
in  hot  water  ;  opake  and  glutinous.  Pre- 
cipitated by  an  infusion  of  nutgalls  ;  pre- 
cipitate redissolved  by  a  heat  of  120°  Fah . 
Insoluble  in  alcohol.  Soluble  in  dilute 
nitric  acid,  and  precipitated  by  alcohol. 
With  nitric  acid  yields  oxalic  acid  and  a 
waxy  matter. 

8.  Indigo.  A  blue  powder.  Taste  in- 
sipid. Insoluble  in  water,  alcohol,  ether. 
Soluble  in  sulphuric  acid.  Soluble  in  ni- 
tric acid,  and  converted  into  bitter  princi- 
ple, and  artificial  tannin. 

9.  Gluten.  Forms  a  ductile  elastic  mass 
with  water.  Partially  soluble  in  water ; 
precipitated  by  infusion  of  nutgalls,  and 
oxigenized  muriatic  acid.  Soluble  in  ace- 
tic and  muriatic  acid.  Insoluble  in  alco- 
hol. By  fermentation  becomes  viscid  and 
adhesive,  and  then  assumes  the  properties 
of  cheese.  Soluble  in  nitric  acid,  and 
yields  oxalic  acid. 

10.  Albumen  Soluble  in  cold  water. 
Coagulated  by  heat,  and  becomes  insolu- 
ble. Insoluble  in  alcohol.  Precipitated 
by  infusion  of  nutgalls.  Soluble  in  nitric 
acid.    Soon  putrefies. 

11.  Fibrin.  Tasteless.  Insoluble  in  w? 


AEG 


YEN 


ter  and  alcohol.  Soluble  in  diluted  alka- 
lies, and  in  nitric  acid.    Soon  putrefies. 

12.  Gelatin.  Insipid.  Soluble  in  water. 
Does  not  coagulate  when  heated.  Preci- 
pitated bs  inf  usion  of  galls. 

13.  Bitter  principle.  Colour  yellow  or 
brown.  Taste  bitter.  Equally  soluble  in 
water  and  alcohol.  Soluble  in  nitric  acid. 
Precipitated  by  nitrate  of  silver. 

14.  Extractive.  Soluble  in  water  and  al- 
cohol. Insoluble  in  ether.  Precipitated  by 
oxigenixed  muriatic  acid,  muriate  of  trn, 
and  muriate  of  illumine  ;  but  not  by  gela- 
tine.   Dyes  fawn  colour. 

15.  Tannin.  Taste  astringent.  Soluble 
in  water  and  in  alcohol  of  0.810.  Preci- 
pitated by  gelatine,  muriat  of  alumiuc, 
and  muriat  of  tin. 

16.  Narcotic  principle.  Crystallizes. 
Sparingly  soluble  in  hot  water  and  alcohol. 

17.  Fixed  oils.  No  smell.  Insoluble 
in  water  and  alcohol.  Forms  soaps  with 
alkalis.  Coagulated  by  earthy  and  me- 
tallic salts. 

18.  Wax.  Insoluble  in  water.  Soluble 
in  alcohol,  ether,  and  oils.  Forms  soap 
with  alkalis.  Fusible. 

19.  Volatile  oil.  Strong  smell.  Insolu- 
ble in  water.  Soluble  in  alcohol.  Liquid. 
Arolatile.  Oily.  By  nitric  acid  inflamed, 
and  converted  into  resinous  substances. 

20.  Camphor.  Strong  odour.  Crys- 
tallizes. Very  little  soluble  in  water.  So- 
luble in  alcohol,  oils,  acids.  Insoluble  in 
alkalis.  Burns  with  a  clear  flame,  and 
volatilizes  before  melting. 

21.  Birdlime.  Viscid.  Taste  insipid.  In- 
soluble in  water.  Partially  soluble  in  alco- 
hol. Very  soluble  in  ether.  Solution  green. 

22.  Resins.  Solid.  Melt  when  heated. 
Insoluble  in  water.  Soluble  in  alcohol, 
ether,  and  alkalies.  Soluble  in  acetic  acid. 
By  nitric  acid  converted  into  artificial  tan- 
nin. 

23.  Guaiacum.  Possesses  the  charac- 
ters of  resins,  but  dissolves  in  nitric  acid, 
and  yields  oxalic  acid  and  no  tannin. 

24-  Balsams.  Possess  the  characters 
of  the  resins,  but  have  a  strong  smell  ; 
when  heated,  benzoic  acid  sublimes.  It 
sublimes  also  when  they  are  dissolved  in 
sulphuric  acid.  By  nitric  acid  converted 
into  artificial  tannin. 

25.  Caoutchouc.  Very  elastic.  Insolu- 
ble in  water  and  alcohol.  When  steeped 
in  ether  reduced  to  a  pulp,  which  adheres 
to  every  thing.  Fusible,  and  remains  li- 
quid.   Very  combustible. 

26.  Gum  resins.  Form  milky  solutions 
with  water,  transparent  with  alcohol.  So- 
luble in  alkalies.  With  nitric  acid  con- 
verted into  tannin.  Strong  smell.  Brittle, 
opake,  infusible. 

27.  Cotton.  Composed  of  fibres.  Taste- 
VOL.  II. 


less.  Very  combustible.  Insoluble  in  wa- 
ter, alcohol,  and  ether.  Soluble  in  alka« 
lis.    Yields  oxalic  acid  to  nitric  acid. 

28.  Suher.  Burns  bright  and  swells. 
Converted  by  nitric  acid  into  suberic  acid 
and  wax.  Partially  soluble  in  water  and 
alcohol, 

29  Wood.  Composed  of  fibres.  Taste- 
less.  Insoluble  in  water  and  alcohol.  So- 
luble in  weak  alkaline  lixivium.  Precipi- 
tated by  acids.  Leaves  much  charcoal 
when  distilled  in  a  red  heat.  Soluble  in 
nitric  acid,  and  yields  oxalic  acid. 

VEINS.  See  Metals,  Metallur- 
gy, and  Ores. 

VENETIAN  BED.     See  Colour- 

MAKING. 

V  ENEER1NG. — Veneering  is  a  species 
of  inlaying  or  marquetry,  in  which  several 
thin  leaves,  or  slips  of  fine  wood,  are  ap- 
plied to  a  ground-work  of  common  wood. 
It  is  performed  in  the  following  manner. 

The  wood  intended  for  veneering,  is 
first  fixed  in  a  vice,  or  sawing  press,  where 
it  i:>  divided  into  leaves,  not  exceeding 
one  line  in  thickness.  Such  leaves  are 
then  cut  into  small  slips  of  various  forms, 
according  to  the  design  proposed :  and, 
when  the  ground-work  is  duly  prepared, 
they  are  cemented  by  means  of  glue,  and 
submitted  to  the  action  of  a  press,  till  the 
whole  becomes  perfectly  dry ;  after  which, 
the  articles  are  scraped  and  polished. 

The  veneering  with  mahogany,  in  con- 
sequence of  the  high  price  of  that  wood, 
is  now  generally  adopted  by  the  cabinet- 
makers. 

VENUS,  Crystals  of.    See  Copper. 

VENTILATION.  Various  contrivances 
have  been  made  for  ventilating  with  fresh 
air  the  holds  of  ships,  hospitals,  grana- 
ries, &c. 

For  warming  and  ventilating  ships  Mr. 
Pettibone  has  given  the  following  obser- 
vations. 

The  application  of  the  following  plan  is 
manifestly  advantageous  in  warming  and 
ventilating  merchant  ships  and  vessels  of 
war,  viz. — A  boiler,  or  air-vessel,  may  be 
fixed  in  furnace,  fire-place  or  camboose; 
and  to  the  bottom  of  the  boiler  a  tube  is 
introduced,  which  passes  from  it  down  the 
inside  of  the  ship  or  vessel,  nearly  to  the 
keel,  where  it  forms  a  curve  and  returns 
again  above  the  deck.  At  this  place  it 
admits  the  external  air,  which  passes 
through  the  tube  into  the  boiler  or  air- 
vessel  ;  and,  after  it  is  heated,  it  passes 
out  of  another  tube  inserted  into  the  up- 
per part  of  the  air-vessel;  and  the  heated 
air  may  then  be  conducted  into  any  part 
of  the  ship  or  vessel.  These  tubes  must 
be  made  double,  and  the  intermediate 
space  between  the  tubes  should  be  filled 
3  T 


VEN 


VER 


with  powdered  charcoal,  so  as  to  prevent 
the  escape  of  heat.  Also,  if  tlx*  receiving 
tube  penetrates  into  the  hold  of  the  ship, 
and  conducts  the  foul  air  within  the  ship, 
into  the  boiler  or  air-vessel,  and,  after  be- 
ing heated  there,  into  another  tube  fixed 
into  the  superior  part  of  the  boiler  or  air- 
vessel,  which  conveys  it  into  the  atmos- 
phere above  the  deck,  where  it  mixes 
With  the  general  mass.  This  improve- 
ment can  be  very  beneficially  applied  to 
ventilate  mines,  wells,  school  rooms,  as- 
sembly rooms,  and  any  apartments  or 
places,  impregnated  with  foul  air. 

To  effect  this  without  warming  the 
room,  the  boiler  or  air-vessel  and  stove 
should  be  placed  above  it.  However,  the 
room  can  be  warmed  with  the  stove  above 
(if  rightly  fitted)  nearly  as  well  as  if  the 
stove  was  below. 

When  it  is  found,  (says  Mr.  Pettibone,) 
that  the  external  air  is  warm,  and  the 
apartment  is  crowded  with  people,  it  is 
proper  that  ventilation  should  take  place 
at  the  top,  at  or  near  the  ceiling. — When- 
ever an  apartment  is  filled  with  contami- 
nated air,  particularly  in  the  summer,  by 
the  perspiration  or  breath  of  a  crowded 
assembly,  or  from  burning  of  candles  or 
lamps,  or  from  any  other  cause,  it  is  of 
much  consequence,  that  tin^pasteboafd, 
or  other  tubes  (filled  between  with  char- 
coal,) should  be  placed  just  above  the 
lights,  and  carried  into  the  external  at- 
mosphere, by  placing  one  or  more  of  Ar- 
gand's  patent  lamps  in  or  near  the  end  of 
the  tubes. — The  air  in  the  tube  becomes 
rarefied ;  and  by  the  current  of  air  up  the 
tubes,  the  ventilation  is  made  to  be  more 
complete. 

An  account  of  Hale's  ventilators  may 
be  seen  in  the  Philosophical  Transactions, 
and  that  of  Abernethy  in  a  late  volume  of 
Phillips's  Monthly  Magazine,  and  in  Dr. 
Gleig's  supplement  to  the  Encyclopedia 
Britannica  of  Edinburgh. 

Mr.  Benjamin  Wynkoop's  contrivance 
for  ventilation  consists  of  four  bellows 
connected  in  a  frame,  and  having  their 
nozzles  opening  into  one  tube  which  de- 
scends from  the  deck  to  any  distance  in 
the  hold  of  the  vessel  ;  and  as  the  frame 
of  the  upper  part  of  the  bellows,  or 
moving  frame,  is  furnished  at  bottom  with 
a  heavy  pendulum  or  weight,  and  the 
other  or  standing  part  of  the  frame,  is  at- 
tached either  to  the  side  of  the  ship,  and 
parallel  therewith,  or  to  some  partition  at 
right  angles  with  the  keel,  or  which  is 
preferable,  to  both,  the  motion  of  the  ship 
keeps  one  or  other  of  them  in  constant 
operation,  and  precludes  the  necessity  of 
manual  labour. 

Jlir-pump  ventilatory  for  the  ventilating  of 
ships,  mines,  prisons,  hospitals,  &c.  in- 


v"nted  by  Richard  Robotham,  of  the  at) 
of  Hudson  (N.  Y.). 

"  It  is  a  single  bellows,  fitted  upon  the 
top  of  a  tube  of  wood,  or  a  trunk  made 
of  plank,  which,  in  a  ship,  stands  in  the 
lowest  part  of  the  hold,  by  the  kelson, 
and  runs  up  through  the  lower  deck. 
The  bellows  is  fixed  on  the  top  of  this 
trunk,  with  a  valve  at  the  usual  place,  at 
the  inlet.  The  outlet  of  the  bellows  is 
made  of  wood,  with  a  square  angle,  which 
turns  upwards,  and  a  valve  in  the  upright 
part,  that  shuts  down,  in  such  manner 
that  the  bellows  fills  from  the  bottom,  and 
discharges  at  the  top.  ]f  the  bellows  dis- 
charges one  barrel  at  a  time,  the  insides 
of  the  trunks  must  be  six  inches  square ; 
it  will  be  then  sufficient  for  a  vessel  of 
three  hundred  tons  ;  but  if  they  are  four 
or  five  times  this  size,  the  machine  may 
be  worked  by  the  labour  of  one  man  ;  or, 
about  one  square  inch  of  enlargement 
may  be  made  in  the  trunks  to  each  gal- 
lon in  the  bellows  :  then  it  will  fill  and 
discharge  about  twenty  times  in  a  minute. 
The  bellows  may  be  made  in  various 
shapes  and  sizes  at  pleasure.  This  im- 
provement consists  altogether  in  filling 
the  bellows  at,  or  from  the  bottom,  and 
discharging  the  contents  at  the  top,  above 
the  upper  deck,  or  out  of  a  port-hole." 
Ventilation  of  Ovens. 

Ventilation  in  the  oven  (says  Mr.  Pet- 
tibone)  is  of  importance.  It  not  only  adds 
to  the  flavour  of  the  articles  baked  or 
cooked,  but  tends  to  expedite  the  process 
In  order  to  perform  this  operation,  a  cast 
or  wrought  iron  pipe  or  tube,  of  the  size, 
of  a  gun-barrel,  should  be  placed  in  the 
hottest  part  of  the  stove  under  the  oven 
plate,  and  one  end  connected  with  the  air 
of  the  room,  or  the  external  air  which  is 
preferable. — The  other  end  is  to  enter  the 
oven  through  the  oven  plate,  at  the  back 
end  of  the  plate  or  oven  ;  then  it  is  to  rise 
nearly  to  the  top.  I  have  then  another 
pipe  leading  downward  from  the  under 
side  of  the  smoke  tube  or  flue,  within  the 
oven,  near  the  oven  plate.  In  this  oven, 
as  the  hot  air  from  without  enters  the  top 
of  the  oven,  it  forces  the  fumes  down- 
wards to  enter  the  pipe  that  leads  into 
the  smoke  flue. —Dampers  or  registers 
are  fitted  in  the  pipes,  to  regulate  the 
current  of  air  going  in  or  out  of  the  oven, 
to  ventilate  it  more  or  less-  Ventilators 
were  invented  by  Dr.  Hales  in  1740. 

VERD1GRISE  is  copper  corroded,  and 
reduced  to  a  very  beautiful  green  rust,  by 
a  vinous  acid.  This  matter,  which  is  use- 
ful to  painters,  is  conveniently  manufac- 
tured at  Montpellier ;  the  vines  of  Lan 
guedoc,  of  which  that  city  is  the  capital  , 
being  very  proper  for  this  preparation. 

The  following  process  for  making  ver* 


VEIi 


digrise  is  described  by  Mr.  Monnet  of  the 
Hoyal  Society  of  Montpellier,  and  is  pub- 
lished among-  the  Memoirs  of  the  Acade- 
my tor  the  years  1750  and  1753. 

Vine-Stalks,  well  dried  in  the  sun,  are 
steeped  during-  eight  days  in  strong  wine, 
and  afterwards  drained.  They  are  then 
put  into  earthen  pots,  and  upon  them 
wine  is  poured  The  pots  are  carefully 
covered.  The  wine  undergoes  the  ace- 
tous fermentation,  which  in  summer  is 
finished  in  seven  or  eight  days,  but  re- 
quires a  longer  time  in  winter,  although 
this  operation  is  always  performed  in  cel- 
lars. When  the  fermentation  is  suffi- 
ciently advanced,  which  may  be  known 
by  observing  the  inner  surface  of  the  lids 
of  the  pots,  which  during  the  progress 
of  the  fermentation  is  continually  wetted 
by  the  moisture  of  the  rising  vapours,  the 
stalks  are  then  to  be  taken  out  of  the 
pots.  These  stalks  are  by  this  method 
impregnated  with  the  acid  of  the  wine, 
and  the  remaining  liquor  is  but  a  very 
weak  vinegar.  The  stalks  are  to  be 
drained  during  some  time  in  baskets,  and 
layers  of  them  are  to  be  put  into  earthen 
pots,  with  plates  of  Swedish  copper,  so 
disposed  that  each  plate  shall  rest  upon, 
and  be  covered  with  layers  of  stalks. 
The  pots  are  to  be  covered  with  lids,  and 
the  copper  is  thus  exposed  to  the  action 
of  the  vinegar,  during  three  or  four  days, 
or  more,  in  which  time  the  plates  become 
covered  with  verdigrise.  The  plates  are 
then  to  be  taken  out  of  the  pots,  and  left 
in  the  cellar  three  or  four  days;  at  the 
end  of  which  time  they  are  to  be  moist- 
ened with  water,  or  with  the  weak  vine- 
gar above  mentioned,  and  left  to  dry. 
When  this  moistening  and  drying  of  the 
plates  has  been  thrice  repeated,  the  ver- 
digrise will  be  found  to  have  considera- 
bly increased  in  quantity,  and  it  may  then 
be  scraped  off  for  sale. 

A  solution  or  corrosion  of  copper,  and 
consequently  a  verdigrise,  may  be  pre- 
pared by  employing  ordinary  vinegar  in- 
stead of  wine,  as  is  directed  in  the  above 
process.  But  it  would  not  have  the  unc- 
uiosity  of  ordinary  verdigrise,  which  qua- 
lity is  necessary  in  painting.  Good  ver- 
digrise, according  to  Macquer,  must  be 
prepared  by  means  of  a  vinous  acid, 
half  acid  and  half  spirit.  Accordingly 
the  success  of  the  operation  depends 
chiefly  on  the  degree  of  fermentation, 
to  which  the  wine  employed  has  been 
carried  :  for  this  fermentation  must  not 
have  been  so  far  advanced,  that  no  sensi- 
bly vinous  or  spirituous  part  remains  in 
the  liquor. 

Verdigrise  is  used  for  painting,  as  it 
furnishes  a  fine  green  colour,  when  mix- 


ed with  oil.  It  enters  also  as  an  ingre- 
dient into  several  plasters  and  ointments. 
In  chemistry,  verdigrise  is  used  for  the 
extraction  of  acetic  acid,  and  for  the  pre- 
paration  of  crystals  of  verdigrise,  or  of 
Venus. 

Chaptal  informs  us,  that  the  fabrication 
of  this  article  was  till  lately  confined  to 
Montpellier,  from  a  prejudice,  that  the 
cellars  of  that  city  alone  were  proper  for 
the  ope  ration.  His  account  of  the  manu- 
facture is  less  ample  than  the  foregoing, 
but  in  effect  the  same.  This  article  is 
also  made  at  Grenoble,  where  ready  made 
vinegar  is  used,  and  sprinkled  on  plates 
of  copper.  This  verdigrise  contains  one- 
sixth  part  less  of  copper  than  that  of 
Montpellier,  and  has  not  the  empyreuvna- 
tic  smell  of  the  latter.  The  vinegar  it 
affords  by  distillation  is  likewise  stronger 
and  in  greater  plenty.  Whence  he  con- 
cludes, that  part  of  the  oxide  of  copper  in 
this  compound  is  really  dissolved,  and 
brought  into  the  saline  state. 

VERDITER  is  a  blue  pigment,  obtain- 
ed by  adding  chalk  or  whiting  to  the  so- 
lution of  copper  in  aquafortis.  It  is  pre- 
pared by  the  refiners,  who  employ  for 
tins  purpose  the  solution  of  copper,  which 
they  obtain  in  the  process  of  parting,  by 
precipitating  silver  from  aquafortis  with 
plates  of  copper.  It  is  said,  that  a  fine 
coloured  verditer  cannot  be  obtained 
from  a  solution  of  copper  prepared  by 
dissolving  directly  that  metal  in  aquafor- 
tis ;  and  that  the  silver  is  necessary. 
We  know,  that  it  is  actually  made  of  a 
good  quality  by  the  refiners  only.  Dr. 
Merret  says  that  it  is  prepared  in  the  fol- 
lowing manner  j  A  quantity  of  whiting  is 
put  into  a  tub,  and  upon  this  the  solution 
of  the  copper  is  poured.  The  mixture  is 
to  be  stirred  every  day  for  some  hours 
together,  till  the  liquor  loses  its  colour. 
The  liquor  is  then  to  be  poured  off,  and 
more  solution  of  copper  is  to  be  added. 
This  is  to  be  repeated  till  the  whiting  has 
acquired  the  proper  colour.  Then  it  is 
to  be  spread  on  large  pieces  of  chalk  and 
dried  in  the  sun. 

We  have  two  kinds  of  verditer  in  the 
English  market :  the  one,  called  refiners* 
verditer,  has  the  form  of  a  very  soft  im- 
palpable powder,and  possesses  a  stronger 
body  of  colour  than  the  other.  The  other 
verditer  has  the  form  either  of  hard  irre- 
gular lumps,  or  powder,  in  which  last 
state  it  is  much  harsher  to  the  feel,  and 
is  by  no  means  so  readily  diffusible  in 
water.  The  best  verditer  is,  as  we  un. 
derstand,  made  by  the  refiners,  not  be- 
cause their  solution  of  copper  possesses 
any  peculiar  advantage  over  any  other 
nitric  solution,  but  because  they  obtain 


TER 


YIN 


it  more  cheaply,  than  if  the  acid  had  not 
been  already  paid  for  in  their  process  of 
parting.  The  value  of  the  article  is  not 
sufficient  to  pay  for  the  expense  of  a  di- 
rect solution  in  that  country. 

Common  verditer  is  made  from  thesul- 
phut  of  copper,  which  may  be  had  at  a 
reasonable  rate  from  the  manufacturers 
at  Sheffield  and  Birmingham  (England). 
We  are  not  acquainted  with  that  part  o; 
their  manufactories  winch  affords  it,  but 
understand,  that  it  is  not  produced  in  a 
direct  way,  but  from  clipping  of  metal, 
or  other  savings]  It  is  frequently  conta- 
minated with  iron.  The  copper  of  a  so- 
lution of  this  sulphat,  is  precipitated  by 
an  addition  of  lime  in  the  making  of 
co7>imon  verditer.  "Whiting  will  not  ef- 
fect a  separation.  The  precipitate  afford- 
ed by  the  lime  is  blue,  but  requires  some 
management  as  to  the  quantities  of  water 
as  well  as  of  the  other  principles,  and  the 
method  of  the  drying,  to  produce  the  best 
effect. 

The  flintiness  or  harshness  of  the  com- 
mon verditer  arises  no  doubt  from  an  ad- 
mixture of  su  '  hat  of  lime;  whereas  in 
the  refiners  -  Mher,  little  of  lime  is 
found;  because  the  nitrate  of  lime  is  very 
soluble  iu  the  w  ater.  If  the  object  should* 
be  found  of  tufficent  commercial  impot- 
tance,  it  i  probable  that  the  blue  oxide 
of  copper  m  ve.diter  might  be  obtained 
by  an  indirect  process  of  transferring  ni- 
tric acid  to  the  metal  Thus,  if  the  so- 
lutions of  nitre,  and  of  sulphat  of  copper, 
be  mixed,  the  alkali  unites  with  the  sul- 
phuric acid,  and  sulphat  of  potash  falls 
down,  if  the  quantity  of  w  ater  be  not  con- 
siderable; at  the  same  time  that  the  nitric 
acid  transferred  to  the  copper  remains  in 
solution. 

Other  methods  of  decomposition  might 
be  easily  pointed  out,  but  every  thing  of 
this  nature  must  be  referred  to  the  test  of 
experiment.  For  in  some  instances,  triple 
compounds  are  formed  where  perfect  de- 
composition was  expected,  and  in  most 
instances  the  complete  edulcoration  of 
the  product  is  required,  and  many  appa- 
rently minute  circumstances  must  be  in- 
vestigated and  attended  to,  where  so  de- 
licate a  thing  as  the  colour  of  a  metallic 
oxide  is  the  object  aimed  at. 

The  refiners'  verditer,  is  more  than 
twice  as  dear  as  the  common.  Both,  are 
used  in  water  colours  only,  chiefly  by  the 
paper  stainers.  It  is  said,  that  the  greater 
intensity  of  colour,  added  to  the  facility 
with  which  it  may  be  uniformly  spread 
over  any  surface,  affords  the  advantage 
even  of  cheapness  to  the  refiners'  verdi- 
ter ;  but  the  last  mentioned  quality  is 
communicated  to  common  Yerditer,  by 


steeping  it  for  several  days  in  water  be. 
fore  it  is  used. 

VERJUICE.— A  kind  of  harsh  austere 
vinegar,  made  of  the  expressed  juice  of 
the  wild  apple  or  crab. 

VERMILION.    See  Mercury. 
VIBRATION  OF  THE  PENDULUM. 
See  Mechanics. 

V1COGNF,  DYE — The  milky  juice  of 
the  white  bell  flowers  is  said  to  impart  a 
beautiful  green  colour,  by  the  addition  of 
alum.  The  juice  of  the  blue  flowers 
alone  lias  been  used  for  painting  and  wri- 
ting; and  Dambourney  asserts,  that  with 
these  flowers  he  dyed  wool  and  cloth  of 
a  fine  vigogne  colour,  having  previously 
immersed  them  in  a  properly  diluted  so- 
lution of  bismuth. 

Dambourney  obtained  from  the  stalks 
and  leaves  of  the  mezereon,  a  fine  vi- 
gogne dye  ;  and  the  stalks  alone,  imparted 
a  beautiful  gold-brown  shade  to  wool, 
previously  dipped  in  a  diluted  solution  of 
bismuth.  From  the  ripe  berries  of  this 
plant,  an  excellent  red  lake  is  prepared 
by  painters. 

VINEGAR.  Essig,  Germ. — Vinegar  is 
a  liquor  of  an  agreeable  smell,  a  plea- 
sant and  strongly  acid  taste,  and  of  a  hue 
varying  from  light  red  to  brown  straw 
colour,  and  is  prepared  by  fermenting 
any  substance  or  compound  which  has 
already  undergone  the  spirituous  fermen- 
tation. Vinegar  therefore  may  be  made 
immediately  from  any  wine,  malt  liquor, 
cyder,  &c.  or  from  the  juice  of  the  grape 
and  other  fruits,  from  infusion  of  malt, 
or  any  saccharine  liquid,  through  the  in- 
termedium of  vinous  fermentation.  Both 
these  methods  are  actually  practised  with 
complete  success. 

The  chemical  properties  of  the  pure 
acid  of  the  different  kinds  of  vinegar 
(which  appears  to  be  the  same  in  all) 
have  been  already  described  under  the 
article  Acetous  Acid,  and  we  shall 
therefore  only  mention  the  usual  pro- 
cesses of  manufacture. 

To  make  vinegar  out  of  a  liquor  con- 
taining suitable  materials,  it  is  only  ne- 
cessary, 1st.  to  allow  some  access  of  air 
to  the  vessel  in  which  it  is  kept,  and,  2d. 
to  keep  it  in  a  temperature  rather  higher 
than  that  of  the  atmosphere  in  this  cli- 
mate, that  is  to  say,  about  75°  to  80°.  It 
is  also  almost  essential  where  a  liquor  al- 
ready fermented  is  employed,  to  add  a 
portion  of  yeast,  or  any  other  ferment, 
for  though  any  fermented  liquor,  if  kept 
in  a  moderate  temperature  in  an  open 
vessel,  will  spontaneously  turn  sour  or  be- 
come changed  to  vinegar,  this  change  is 
too  gradual  to  produce  this  acid  in  per- 
fection, and  the  first  acetified  portion 


VIN 


YIN 


turns  mouldy  before  the  last  has  become 
sour.  But  where  the  substance  employ- 
ed has  not  yet  undergone  fermentation, 
the  whole  process  of  the  vinous  and  sub- 
sequent acetous  fermentation  will  go  on 
uninterruptedly  with  the  same  ferment 
which  at  first  set  it  in  action,  which  hap- 
pens, for  example,  in  the  making  vinegar 
from  malt,  or  from  sugar  and  water. 

As  even  vinegar  is  not  the  ultimate 
change  which  a  vinous  liquor  spontane- 
ously assumes,  there  is  a  period  in  the 
process  of  the  manufacture  in  which  the 
acid  is  in  its  highest  degree  of  strength 
and  perfection,  after  which,  if  the  pro- 
cess is  not  stopped,  the  liquor  speedily 
deteriorates,  the  acetous  acid  gradually 
disappears,  and  only  an  offensive  mouldy 
watery  liquid  remains,  with  scarcely  any 
sourness.  It  belongs  therefore  to  the 
skill  and  experience  of  the  manufacturer 
to  know  when  his  vinegar  is  complete, 
and  fit  to  be  drawn  off  and  close! v  bar- 
relled. 

Vinegar  was  doubtless  (as  its  name 
imports)  originally  made  from  w  ine,  and 
this  is  the  material  which  furnishes  it  pro- 
bably in  the  greatest  perfection,  and  is 
employed  solely  in  the  wine  countries. 
It  is  prepared  by  adding  wine  lees  to 
wine,  which  excites  a  new  fermentation 
that  is  kept  up  till  the  whole  is  changed 
to  vinegar.  Any  wine  will  answer  the 
purpose ;  the  best  and  fullest-bodied 
wine  gives  the  strongest  vinegar,  and  that 
which  is  already  soured  and  injured  by 
keeping  may  be  applied  to  this  use.  The 
actual  method  pursued  in  Paris  is  the  fob 
mowing.  A  quantity  of  wine  lees  is  put 
Into  a  large  tun,  and  worked  up  with 
wine  sufficient  to  render  it  very  fluid. 
This  is  then  put  into  cloth  sacks,  which 
are  arranged  in  a  large  iron-bound  wood- 
en vat,  the  heavy  cover  of  which  is  laid 
over  them,  and  serves  as  a  press,  that  is 
gradually  screwed  down  till  all  the  li- 
quor is  pressed  out.  The  wine,  thus  load- 
ed with  the  extractive  and  tartareous 
matter  of  the  lees,  is  distributed  in  large 
casks  set  upright,  through  the  heading  of 
which  a  hole  is  cut  which  is  constantly 
left  open.  In  summer  these  casks  are 
simply  set  in  the  sun,  but  in  winter  they 
are  arranged  in  a  stoved  room.  The  fer- 
mentation comes  on  in  a  day  or  two,  and 
when  it  has  got  to  its  height,  so  much 
heat  is  excited,  that  sometimes  the  hand 
can  hardly  be  borne  in  it.  In  this  case,  it 
must  be  checked  by  a  cooler  air,  and  by 
adding  some  fresh  wine  to  the  casks,  and 
indeed  it  is  in  a  due  regulation  of  the  heat 
that  most  of  the  practical  skill  of  the  ma- 
ker consists.  The  process  goes  on  in  this 
M  ay  till  the  whole  of  the  wine  is  tho- 


roughly acidified,  which  requires  about  a 
fortnight  in  summer  and  a  month  in  win- 
ter; after  which  the  new  vinegar  is  put 
into  barrels,  at  the  bottom  of  which  are 
laid  a  good  many  chips  of  beech  wood. 
Here  it  remains  for  about  a  fortnight, 
during  which  time  it  clarifies,  and  the 
clear  part  is  then  drawn  off  and  kept  in 
well  closed  casks.  These  beech  chips 
may  be  used  over  and  over  again  for  se- 
veral years. 

The  natural  colour  of  good  wine  vine- 
gar is  a  very  pale  red,  but  a  higher  colour 
is  given,  it'  cU  sired,  by  the  addition  of  el- 
der-berries. 

There  are  several  slight  variations  in 
the  mode  of  making  wine  vinegar,  but 
which  need  not  be  detailed.  They  all 
consist  in  exciting  a  fresh  fermentation  in 
wine,  and  keeping  it  up  in  a  moderate 
degree  till  acetiheation  is  complete.  Ma- 
ny refuse  parts  of  the  vine  are  of  use  for 
this  purpose,  such  as  the  husks,  the  sour 
succulent  twigs,  the  marc  or  cake  left  in 
the  wine  press,  and  the  like  ;  and  after 
they  have  once  served,  they  are  still  more 
valuable,  as  the  acid  which  they  natural- 
ly contain,  or  which  is  evolved  by  them, 
is  more  readily  produced. 

Wine  may  also  be  converted  to  good 
vinegar  without  these  additions,  simply  by 
adding  wine,  especially  when  on  the  fret, 
to  vinegar  already  made,  and  exposing  it 
to  a  proper  heat.  In  this  way  many  ma- 
nufacturers proceed,  keeping  their  casks 
always  full  by  taking  out  of  them  at  inter- 
vals about  a  third  or  fourth  par*,  reple- 
nishing them  with  wine,  and  again  bring- 
ing the  contents  to  the  state  of  vinegar. 

In  Europe  vinegar  is  chiefly  made  from 
\v.u\i  The  following  is  the  usual  process 
in  London.  A  mash  of  malt  and  hot  wa- 
ter is  vr.ade,  which,  after  infusion  for  an 
hour  and  a  half,  is  conveyed  into  a.  cooler 
a  few  inches  deep,  and  thence,  when  suf- 
ficiently cooled,  into  large  and  deep  fer- 
menting tuns,  where  it  is  mixed  with 
yeast,  and  kept  in  fermentation  for  four 
or  five  days.  The  iiquor  (which  is  now  a 
strong  ale  without  hops)  is  then  distribut- 
ed into  smaller  barrels  set  close  together 
in  a  stoved  chamber,  and  a  moderate 
heat  is  kept  up  for  about  six  weeks,  dur- 
ing which  the  fermentation  goes  on  equal- 
ly and  uniformly  till  the  whole  is  soured. 
This  is  then  emptied  into  common  bar- 
rels, which  are  set  in  rows  (often  of  many 
hundreds)  in  a  field  in  the  open  air,  the 
bung-hole  being  just  covered  with  a  tile 
to  keep  ofT  the  wet,  but  to  allow  a  free  ad- 
mission of  air.  Here  the  liquor  remains 
for  four  or  five  months,  according  to  the 
heat  of  the  weather,  a  gentle  fermentation 
being  kept  up,  till  it  becomes  perfect  vi- 


V1N 


VIN 


negar.  This  is  finished  in  the  following1 
way.  Large  tuns  are  employed,  with  a 
false  bottom,  on  which  is  put  a  quantity 
of  the  refuse  of  raisins  or  other  fruit  left 
by  the  makers  of  raisin  and  other  home- 
made wines,  called  technically  rape. 
These  rape  tuns  are  worked  by  pairs ; 
one  of  them  is  quite  filled  with  the  vine- 
gar from  the  barrels,  and  the  other  only 
three-quarters  full,  so  that  the  fermenta- 
tion is  excited  more  easily  in  the  latter 
than  the  former,  and  every  day  a  portion 
of  the  vinegar  is  laded  from  one  to  the 
other  till  the  whole  is  completely  finished 
and  fit  for  sale. 

Vinegar,  as  well  as  fruit-wines,  is  often 
made  in  small  quantity  for  domestic  uses, 
and  the  process  is  by  no  means  difficult. 
The  materials  may  be  either  brown  sugar 
and  water  alone,  or  sugar  with  raisins, 
currants,  and  especially  ripe  gooseber- 
ries. These  should  be  mixed  in  the  pro- 
portions which  would  give  a  strong  wine, 
put  into  a  small  barrel,  which  it  should 
■fill  about  three-fourths,  and  the  bung- 
hole  very  loosely  stopped.  Some  yeast, 
or,  what  is  better,  a  toast  sopped  in  yeast 
should  be  put  in,  and  the  barrel  set  in 
the  sun  in  summer,  or  a  little  way  from  a 
fe^in  winter,  and  the  fermentation  will 
soon  begin.  This  should  be  kept  up  con- 
stant but  very  moderate,  till  the  taste 
and  smell  indicate  that  the  vinegar  is  com- 
plete It  should  be  poured  off  clear  and 
bottled  carefully,  and  it  will  keep  much 
better  if  it  is  boiled  for  a  minute,  cooled 
and  strained  before  bottling. 

Mr.  Joseph  Cooper,  of  New  Jersey, 
says  Dr.  Mease,  makes  his  vinegar  of 
good  bodied  cyder,  fills  the  barrel  one- 
third  full,  and  "permits  it  to  stand  with 
the  bung-holes  slightly  covered  for  at 
least  nine  months.  If  the  fermentation 
does  not  proceed  with  sufficient  rapidity, 
he  draws  off  a  few  quarts  of  the  liquor, 
and  after  boiling  and  skimming  it,  returns 
it  again  into  the  cask.  Mr.  Cooper  con- 
firms the  utility  of  the  practice  of  adding 
cyder  or  rye-spirit  to  weak  vinegar  to  in- 
crease its  strength. 

Mr.  William  SheafT,  of  Philadelphia, 
continues  the  Dr.  adds  one  quart  of  bruis- 
ed and  ripe  sumach-berries,  after  being 
boiled  with  half  an  ounce  of  cream  of  tar- 
tar, to  every  barrel  of  cyder  destined  for 
vinegar.  He  fines  it,  by  pouring  in  one 
quart  of  fresh  blood,  beaten  up  with  a 
handful  of  salt. 

To  prevent  a  mould  forming  on  vine- 
gar, several  methods  have  been  propos- 
ed. 1.  To  prepare  vinegar  very  strong 
and  sour.  2.  To  concentrate  the  vinegar 
by  freezing,  after  which  a  hole  is  made  in 
the  crust  of  ice  which  covers  it,  through 


which  the  part  not  congealed  is  let  out, 
and  afterwards  may  be  bottled.  By  this 
process,  more  than  one  half  is  lost.  3. 
To  fill  the  bottles  and  keep  them  well 
corked.  4.  To  distil  the  vinegar  in  a 
glass  retort.  The  following  is  the  easiest 
method. 

Boil  vinegar  in  a  well  tinned  kettle  for  a 
quarter  of  an  hour,  and  bottle  it,  or  fill 
the  bottles  with  vinegar,  and  put  them  in- 
to a  kettle  full  of  water  upon  the  fire. 
After  the  water  has  boiled  for  an  hour, 
the  bottles  are  taken  out  of  the  pot,  and 
corked.  Vinegar  thus  boiled  will  keep 
for  several  years  without  growing  turbid 
or  mouldy. 

The  following  remarks  are  from  the 
pen  of  Dr.  Willich. 

Wine-vinegar. ...Let  any  quantity  of  vi- 
nous liquor  be  mixed  with  its  own  lees  or 
faeces,  or  with  the  acid  and  austere  stalks 
of  the  vegetable  from  which  wine  was 
prepared.  The  whole  must  be  frequent- 
ly stirred,  and  either  exposed  to  the  sun, 
or  deposited  in  a  warm  place  :  after  stand- 
ing a  few  days,  it  will  ferment,  become 
sour;  and,  in  a  fortnight,  it  will  be  con- 
veited  into  vinegar.. ..Such  is  the  usual 
manner  of  producing  this  acid  ;  which  is 
frequently  rectified  by  distillation,  when 
it  is  known  under  the  name  of  distilled 
vinegar. 

Cyder. vinegar,  may  be  made  by  ferment- 
ing new  cyder  with  the  must  of  apples,  in 
a  warm  room,  or  in  the  open  air,  where  it 
should  be  exposed  to  the  sun  ;  and,  in  the 
course  of  a  week  or  nine  days,  it  will  be 
fit  for  use. 

Another  method  of  preparing  vinegar, 
is  that  published  by  M  Heber :  it  consists 
in  exposing  a  mixture  of  72  parts  of  wa- 
ter, a  id  four  of  rectified  malt-spirit,  in  a 
temperature  of  from  70  to  80°  of  Fahren- 
heit, for  about  two  months  ;  at  the  expi- 
ration of  which  the  acetous  process  will 
be  completed....A  cheaper,  though  more 
tedious  mode,  is  that  of  dissolving  2  lbs. 
of  molasses  in  nine  quarts  of  boiling  wa- 
ter :  this  solution  must  be  poured  into  a 
vessel  containing  a  large  quantity  of  cow- 
slips ;  and,  when  the  mixture  becomes 
cool,  a  gill  of  yeast  should  be  added. 
The  whole  is  then  to  be  exposed  to  the 
rays  of  the  sun:  at  the  end  of  three 
months,  it  may  be  bottled  for  use,  and 
will  be  of  peculiar  service  in  pickling. 

Tarragon-vifiegar,  is  manufactured,  by 
infusing  one  pound  of  the  leaves  of  that 
vegetable  (winch  have  been  gathered  a 
short  time  before  it  flowers)  in  one  gallon 
of  the  best  vinegar,  for  the  space  of  14 
days  ;  when  it  should  be  strained  through 
a  flannel  bag;  and  a  drachm  of  isinglass, 
dissolved  in  cyder,  must  then  be  added  j 


VOL 


VOL 


the  whole  be  carefully  mixed,  and  de- 
canted into  bottles  for  a  month.  Thus, 
the  liquor  will  acquire  a  most  exquisite 
flavour  ;  it  will  become  remarkably  fine, 
and  almost  colourless. 

Vinegar  contains  a  considerable  quan- 
tity of  colouring  extractive  matter,  from 
which  it  can  only  be  freed  by  distillation, 
the  process  of  which,  together  with  the 
chemical  properties  of  this  acid,  have 
been  mentioned  under  the  article  Acetous 
Jcid. 

When  vinegar  is  long  kept,  especially 
exposed  to  the  air,  it  becomes  muddy,  ac- 
quires a  mouldy  unpleasant  smell,  loses 
its  clear  red  colour  and  all  its  properties, 
and  finally  is  changed  to  a  slimy  muci- 
lage and  water. 

VIOLET.— The  odorata,  or  Sweet 
Violet,  is  perennial;  grows  in  warm 
lanes,  hedges,  and  ditch-banks,  especially 
in  clayey  or  rnarly  soils  :  flowers  in  the 
months  of  April  and  May...  Both  the  blos- 
soms and  seeds  of  this  plant  are  mildly 
laxative;  and,  when  taken  in  doses  of 
from  40  to  80  grains,  the  powdered  root 
operates  as  a  purgative,  and  likewise  as 
an  emetic. ...Large  quantities  of  violets  are 
cultivated  at  Stratford-upon-Avon,  for 
their  petals,  to  impart  their  colour  to  «;r- 
rup  of  violets  ;  an  officinal  preparation  of 
which  is  kept  in  the  shops,  and  proves  an 
agreeable  and  useful  laxative  for  children. 
Such  syrup  may  also  be  employed  in  ma- 
ny chemical  inquiries,  for  discovering  the 
presence  of  an  acid,  or  an  alkali ;  the 
former  changing  the  blue  colour  to  a  red, 
and  the  latter  to  a  green  :  though  slips  of 
white  paper,  stained  with  this  juice,  and 
preserved  from  the  access  of  air  and 
light,  may  serve  as  a  substitute  for  that 
purpose. 

VIOLET  DYE.    See  Dyeing. 

VITAL  AIR.    See  Oxygen. 

VITRIFICATION.    See  Glass. 

VITRIOL,  native.— It  is  more  or  less 
soluble  in  water,  and  is  a  mixture  in  va- 
rious proportions  of  the  sulphates  of  iron, 
copper,  and  zinc. 

It  not  unfrequently  occurs  in  caverns 
and  shafts,  in  argillaceous  schistus,  and  in 
old  mines,  especially  such  as  abound  in 
blende  and  pyrites. 

VITRIOL,  blue.    See  Copper. 

VITRIOL,  green.    See  Iron. 

VITRIOL,  white.    See  Zinc 

VITRIOLIC  ACID.  See  Sulphuric 
Acid. 

VOLATILITY.  That  property  of  bo- 
dies  by  which  they  are  disposed  to  as- 
sume  the  vapourous  or  elastic  state,  and 
quit  the  vessels  in  which  they  are  placed. 
In  many  instances  of  chemical  operation, 
the  most  simple  substances  are  found  to 


be  the  most  volatile,  and  many  principles 
are  rendered  more  fixed  by  combination. 
This  is  the  most  general  observation  ;  but 
there  area  number  of  instances,  in  which 
volatility  follows  from  combination,though 
for  the  most  part  less  in  degree  than  was 
possessed  before  by  the  more  volatile  of 
the  matters  so  combined.  Of  all  substan- 
ces known  the  earths,  are  the  less  vola- 
tile, next  to  these  are  some  of  the  metals, 
and  these  are  followed  by  the  fixed  alka- 
lies, and  a  few  of  the  acids.  All  other 
bodies  possess  considerable  volatility.— 
Very  volatile  bodies,  are  in  many  instan- 
ces fixable  in  combination  with  others, 
by  the  sudden  application  of  a  fusing 
heat. 

VOLCANOES.  The  combustion  of 
those  enormous  masses  of  bitumen,  which 
are  deposited  in  the  bowels  of  the  earth, 
produces  \olcanoes.  They  owe  their 
origin  more  especially  to  the  strata  of 
pyritous  coal.  The  decomposition  or  ac- 
tion of  water  upon  the  pyrites,  determines 
the  heat,  and  the  production  of  a  great 
quantity  of  hydrogen,  which  exerts  itself 
against  the  surrounding  obstacles,  and 
at  length  breaks  them.  This  effect  ap- 
pears to  be  the  chief  cause  of  earth- 
quakes ;  but  when  the  concourse  of  air, 
facilitates  the  combustion  of  the  bitumen, 
and  the  hydrogen,  the  flame  is  seen  to 
issue  out  of  the  chimneys  or  vents,  which 
are  made :  and  this  occasions  the  fire  of 
volcanoes. 

There  are  many  volcanoes  still  in  an 
active  state  on  our  globe,  independent  of. 
those  of  Italy,  which  are  the  most-known. 
The  Abbe  Chappe  has  described  three 
burning  in  Siberia.  Anderson  and  Von 
Troil  has  described  those  of  Iceland. — 
Asia  and  Africa  contain  several :  and  we 
find  the  remains  of  these  fires  or  volacnic 
products,  in  all  parts  of  the  globe. 

Naturalists  inform  us,  that  all  the  sou- 
thern islands  have  been  volcanized  ;  and 
they  are  seen  daily  to  be  formed  by  the 
action  of  these  subterraneous  fires.  The 
black  colour  of  the  stones,  their  spongy 
texture,  the  other  products  of  fire,  and 
the  identity  of  these  substances,with  those 
of  the  volcanoes  at  present  burning,  are 
all  in  favour  of  the  opinion,  that  their  ori- 
gin was  the  same. 

When  the  decomposition  of  the  pyrites 
is  advanced,  and  the  vapours  and  elastic 
fluids  can  no  longer  be  contained  in  the 
bowels  of  the  earth,  the  ground  is  shaken, 
and  exhibits  the  phenomena  of  earth- 
quakes. Mephitie  vapours  are  multipli- 
ed on  the  surface  of  the  ground,  and 
dreadful  hollow  noises  are  heard.  In  Ice- 
land, the  rivers  and  springs  are  swallow- 
ed up  ;  a  thick  smoke  mixed  with  spark* 


VOL 


VOL 


and  lightning,  is  then  disengaged  from 
the  crater ;  and  naturalists  have  observed, 
that,  when  the  smoke  of  Vesuvius  takes 
the  form  of  a  pine,  the  eruption  is  near  at 
hand. 

To  these  preludes,  which  show  the  in- 
ternal agitation  to  be  great,  and  that  ob- 
stacles oppose  the  issue  of  the  volcanic 
matters,  succeeds  an  eruption  of  stones 
and  other  products,  which  the  lava  drives 
before  it;  and  lastly  appeals  a  river  of 
lava,  which  Hows  out,  and  spreads  itself 
down  the  side  of  the  mountain.  At  this 
period  the  calm  is  restored  in  the  bowels 
of  the  earth,  and  the  eruption  continues 
without  earthquakes.  The  violent  efforts 
of  the  included  matter,  sometimes  cause 
the  sides  of  the  mountain  to  open  ;  ftid 
this  is  the  cause  which  has  successively 
formed  the  smaller  mountains  that  sur- 
round volcanoes.  Montenuevo,  which  is 
180  feet  high,  and  300  in  breadth,  was 
formed  in  a  night. 

This  crisis  is  sometimes  succeeded  by 
an  eruption  of  ashes,  which  darken  the 
air.  These  ashes  are  the  last  result  of  the 
alteration  of  the  coals  ;  and  the  matter 
which  is  first  thrown  out,  is  that  which 
the  heat  has  half  vitrified.  In  the  year 
1767,  the  ashes  of  Vesuvius  were  carried 
20  leagues  out  to  sea,  and  tae  streets  of 
Naples  were  covered  with  them.  The 
report  of  Dion,  concerning  the  eruption 
of  Vesuvius  in  the  reign  of  Titus,  wherein 
the  ashes  were  carried  into  Africa,  Egypt 
and  Syria,  seems  to  be  fabulous.  Mr.  de 
Saussure-pbserves,  that  the  soil  of  Rome 
is  of  this  character,  and  that  the  famous 
catacombs,  are  all  made  in  the  volcanic 
ashes. 

It  must  be  admitted,  however,  that  the 
force  with  which  all  the  products  are 
thrown  is  astonishing.  In  the  year  1769, 
a  stone  12  feet  high  and  4  in  circumfer- 
ence, was  thrown  to  the  distance  of  a 
quarter  of  a  mile  from  the  crater :  and 
in  the  year  1771,  Sir  William  Hamilton 
observed  stones  of  an  enormous  size, 
which  employed  eleven  seconds  in  fall- 
ing. This  indicates  an  elevation  of  near 
2000  feet. 

The  eruption  of  volcanoes  is  frequent- 
ly aqueous  :  the  water,  which  is  confined. 


and  favours  the  decomposition  of  the  py- 
rites, is  sometimes  strongly  thrown  out 
Sea  salt  is  found  among  the  ejected  mat- 
ter, and  likewise  sal  ammoniac.  In  the 
year  1630,  a  torrent  of  boiling  water,  mix- 
ed with  lava,  destroyed  Portici  and  Torre 
del  G  eco.  Sir  W.  Hamilton  saw  boihnjr 
water  ejected.  The  springs  of  boiling 
water  in  Iceland,  and  all  the  hot  springs 
which  abound  at  the  surface  of  the  globe, 
owe  their  heat  only  to  the  decomposition 
of  pyrites. 

Some  eruptions  are  of  a  muddy  sub- 
stance ;  and  these  form  the  tufa,  and  the 
puzzolano.  The  eruption  which  buried 
Herculaneum  is  of  this  kind.  Sir  W.  Ha- 
milton found  an  antique  head,  the  impres- 
sion of  which  was  well  enough  preserved 
to  answer  the  purpose  of  a  mould.  Her- 
culaneum at  the  least  depth  is  70  feet  un- 
der the  surface  of  the  ground,  and  in  ma- 
ny places  120. 

The  puzzolano  is  of  various  colours. 
It  is  usually  reddish  ;  sometimes  gray, 
white,  or  green  ;  it  frequently  consists  of 
pumice  stone  in  powder  ;  but  sometimes 
it  is  formed  of  oxided  clay.  One  hun- 
dred parts  of  red  puzzolano  afforded 
Bergman,  silex  55,  alumine  20,  lime  5, 
iron  20.- 

When  the  lava  is  once  thrown  out  of 
the  crater,  it  rolls  in  large  rivers  down 
the  side  of  the  mountain  to  a  certain  dis- 
tance, which  forms  the  currents  of  lava, 
the  volcanic  causeways,  &.c.  The  surface 
of  the  lava  cools,  and  forms  a  solid  crust, 
under  which  the  liquid  lava  flows.  After 
the  eruption,  this  crust  sometimes  re- 
mains, and  forms  hollow  galleries,  which 
Messrs.  Hamilton  and  Ferber  have  visit- 
ed :  it  is  in  these  hollow  places  that  the 
sal  ammoniac,  the  muriate  of  soda,  and 
other  substances,  sublime.  A  lava  may 
be  turned  out  of  its  course,  by  opposing 
banks  or  dikes  against  it :  this  was  done 
in  1669,  to  save  Catania  ;  and  Sir  W.  Ha- 
milton proposed  it  to  the  king  of  Naples, 
to  preserve  Portici. 

The  currents  of  lava  sometimes  remain 
several  years  in  cooling.  Sir  W.  Hamil- 
ton observed,  in  1769,  that  the  lava  which 
flowed  in  1766  was  still  smoking  in  some 
places. 


WAG 


WAG 


W 


WADD,  a  name  given  to  plumbago,  or 
black  lead. 

WADD,  BLACK,  an  ore  of  manganese, 
found  in  Derbyshire,  F.ngland,  remarka- 
ble for  taking  fire  with  linseed  oil. 

WAGGON,  a  species  of  wheel  car- 
riage, the  form  of  which  varies  according 
to  the  purpose  designed.  We  do  not 
mean  to  treat  very  extensively  on  this 
subject,  but  to  add  a  few  remarks  on  car- 
riages, wheels,  the  draught  of  horses,  &c. 
and  refer  the  reader  for  more  particular 
information  to  Anderson's  Dissertation, 
Recreations  in  Agriculture,  and  Walker's 
Lectures.  For  information  on  rail-roads, 
see  Railway. 

The  following  observations  are  made 
principally  from  facts. 

Dr.  Wiltich  observes,  that  few  imple- 
ments of  husbandry  are  of  greater  im- 
portance, or  admit,  perhaps,  of  more  es- 
sential improvements,  than  wheel-car- 
riages. Hence  we  cannot  but  express 
our  surprise  at  the  infatuation  of  those 
farmers,  who  employ  large  waggons,  on 
the  erroneous  principle,  that  a  greater 
quantity  may  thus  be  carried  atone  time; 
while  they  overlook  the  injury  which 
such  unwieldy  machines  occasion,  both 
iii  their  fields,  and  particularly  on  roads, 


by  making  deep  ruts,  and  otherwise  tear- 
ing or  breaking  up  the  soil.  The  princi- 
pal objection  tq  the  use  of  these  heavy 
vehicles  on  farms,  is  their  weight;  which 
requires  an  increased  number  of  horses  or 
cattle,  that  might  be  more  profitably  em- 
ployed in  tillage.  The  same  observation 
is  applicable  to  the  common  road  or  stage- 
waggons  :  these  usually  weigh  about  2^ 
tons,  and  are  drawn  by  8,  10,  or  more 
horses,  according  to  the  distance  to  which 
they  travel.  Now,  a  single  horse,  of  a 
moderate  size,  will,  in  a  well-constructed 
vehicle,  and  on  tolerable  roads,  draw 
30  cwt.  with  ease,  independently  of  the 
weight  occasioned  by  the  cart :  and  it 
will  perform  this  task  for  a  series  of  days, 
months,  and  even  years.  But,  if  the  com- 
mon waggons  were  laden  according  to 
such  draught,  they  ought  to  carry  from 
20  to  40  tons  ;  a  weight  exceeding  their 
strength,  and  incompatible  with  their 
mode  of  construction.  The  superiority 
of  small  carriages  being  too  evident  to 
require  any  farther  demonstration,  we 
shall  subjoin  a  table,  exhibiting  the  load 
which  waggons  and  carts  are  permitted  to 
draw  on  the  turnpike-roads  in  England ; 
and  which  includes  both  the  whole  inGum- 
bent  load,  and  the  vehicle  itself. 


Summer  Weight.  Winter  Weight, 


Waggons,  with  wheels  not  exceeding  9  inches, 
Ditto,  with  wheels  not  exceeding  6  inches, 
Ditto,  with  wheels  not  exceeding  3  inches, 
Carts,  with  wheels  not  exceeding  9  inches, 
Ditto,  with  wheels  not  exceeding  6  inches, 
Ditto,  with  wheels  not  exceeding  3  inches, 


tons.  cwt.  qrs. 
6    0  0 
5 
10 
0 
12 
10 


tons.  cwt.  qrs, 

~  10  0 

15  0 

0  0 

15  0 

7  0 

7  0 


We  do  not  know,  whether  any  regula- 
tion exists  with  respect  to  the  turnpike 
roads  of  the  United  States,  but  this  much 
is  certain,  that  if  an  uniform  custom  was 
established,  the  teams  would  be  restrict- 
ed in  their  loads,  and  carriages  generally 
be  subject  to  better  regulation.  In  a  re- 
port made  to  the  house  of  commons,  it 
appears  that  this  subject  has  been  se- 
riously considered,  and  several  acts  of 
parliament  have  been  made  to  this  end. 

Mr.  Walker  made  several  experiments 
on  the  subject  of  draught  horses,  and  in 
relation  generally  to  wheel  carriages.  He 
observes,  that  single  horse  carts  are  pre- 
ferable to  teams ;  that  tour,  horses,  with 
VOL.  II. 


each  a  properly  constructed  cart,  will 
draw  much  more,  and  with  more  eas<J  to 
themselves,  than  when  they  are  yoked  in 
a  team  to  one  cart ;  because,  in  that  case, 
three  of  the  horses  must  draw  horizontal- 
ly, and  consequently  in  a  m^ner  incon- 
sistent with  their  mechanism,  and  the 
established  laws  of  n*echanics.  The 
horse's  collar  is  also  drawn  against  his 
throat,  by  which  hi."  breathing  is  inter- 
rupted ;  and  in  c*rt  teams,  (where  the 
horses  are  not  marshalled,  as  in  wag. 
gons,)  one  horse  is  standing  still,  perhaps, 
while  another  *s  wasting  his  strength  in 
pulling  him  forward...  One  horse,  to  re- 
lieve himself,  leans  on  one  way  out  of  the 
3  u 


WAG 


WAG 


Jine  of  draught,  while  another  is  leaning 
a  contrary  way ;  in  short,  their  strength 
is  seldom  united. 

From  a  number  of  expei'iments  made 
by  Mr  Walker,  for  the  purpose  of  deter- 
mining the  proper  draught,  there  ap- 
peared to  be  an  evident  disadvantage  in 
drawing  from  above  the  centre  ;  and  on 
tne  contrary,  a  considerable  increase  of 
power  in  drawing  from  the  axles.  Hence 
he  concludes,  as  the  splinter  bar,  or 
point  of  draught,  in  most  carriages,  is 
placed  about  one  fourth  the  diameter  of 
the  fore  wheel  above  its  centre,  it  is  evi- 
dent, that  a  pressure  equal  to  one  fifth  of 
whatever  weight  lies  upon  it,  is  actually 
added  to  the  natural  weight,  by  this  situa- 
tion of  the  point  of  draught.  For  24  oz. 
surmounted  the  obstacle  when  the  pull 
was  from  the  centre,  and  30  oz.  were  re- 
quired to  surmount  it,  at  half  the  length 
of  a  spoke  above  the  centre. 

From  Mr.  Walker's  experiments  to 
ascertain  the  best  proportions  between 
the  height  of  the  fore  and  hind  wheels,  it 
appeared,  that  there  was  little  superiority 
or  inferiority  in  all  the  variety  of  combina- 
tions of  heights  between  fore  and  hind 
wheels.  Fore  wheels,  however,  of  four 
feet  eight  inches,  and  hind  wheels  of  five 
feet  six  inches,  seem  to  have  what  little 
advantage  there  is.  To  the  objection 
which  might  be  made  against  these  di- 
mensions, founded  upon  the  inconveni- 
ences arising  to  the  coach-maker  in  alter- 
ing the  routine  of  his  business,  he  replies, 
it  is  certainly  as  easy  to  fix  the  splinter- 
bar  under  the  futchells,  as  upon  them  ; 
and  1  see  no  great  outrage  that  would  be 
done  to  appearance  and  fashion,  if  the 
buttons  on  which  the  traces  are  looped, 
were  wider  the  splinter-bar  instead  of  be- 
ing at  the  top.  In  these  cases  the  draught 
would  have  all  its  mechanical  advan- 
tages, and  the  horses  would  draw  agree- 
ably to  their  form  and  anatomy  ;  the  pole 
would  have  the  same  command  of  the 
carriage  down  hill,  and  the  same  com- 
mand in  turning,  as  in  the  present  me- 
thod. 

Common  experience  will  inform  us, 
that  when  &  horse  is  to  convey  a  certain 
weight,  he  ot^ht,  that  he  may  draw  the 
belter,  to  have  ^  proportionable  weight 
on  his  back  or  shoulders.  A  horse  in  a 
two-wheeled  cart,  m  which  there  is  a  ton 
weight,  when  it  is  in  tquilibrio,  will  not 
be  able  to  draw  it ;  but  when  there  are 
fifty  or  sixty  pounds  bearing  on  his  back, 
he  will  draw  it  with  ease.  if  it  be  two  or 
three  tons,  when  he  bears  one  hundred 
or  two  hundred  pounds  on  his  back,  he 
will  be  able  to  draw  the  load,  because  the 
wheels  of  a  cart  are  very  high. 


When  a  horse  draws  hard,  he  bends 
forward,  and  brings  his  breast  nearer  the 
ground  ;  and  then,  if  the  wheels  be  very 
high,  he  is  pulling  the  carriage  against 
the  ground. 

A  horse,  tackled  in  a  waggon,  will 
draw  two  or  three  tons  weight,  because 
the  line  of  traction  is  below  his  breast. 

It  is  very  common,  when  one  horse  is 
drawing  a  heavy  load,  to  see  his  fore-fed 
rise  from  the  ground,  and  he  will  nearly 
stand  an  end.  It  is  usual  in  this  case  to 
add  a  weight  on  his  back,  to  keep  his 
fore-feet  down,  by  a  person  mounting  on 
him,  which  will  enable  him  to  draw  the 
load  he  could  not  move  before. 

The  case  is  nearly  the  same  in  apply- 
ing the  strength  of  a  man  in  wheeling  a 
load  in  a  wheelbarrow.  When  most  of 
the  load  lies  on  the  wheel,  he  will  slip 
and  not  be  able  to  get  forward  ;  but  when 
bringing  the  weight  nearer  his  arms,  he 
will  be  able  to  drive  it  forward.  In  draw- 
ing a  heavy  garden-roll,  if  the  axis  of  mo- 
tion were  even  with  that  part  of  his  body 
where  his  arms  are  extended,  he  could 
not  be  able  to  draw  it  along ;  but  will 
draw  it  easily  if  the  line  of  traction  be 
low. 

In  a  loaded  cart  which  hangs  nearly  in 
equilibrio,  if  two  men  were  to  take  it  by 
the  shafts,  then  they  would  not  be  ablo 
to  move  it ;  but  one  of  them  in  the  shafts, 
and  the  other  behind  the  cart,  pushing 
the  breech  upward  as  well  as  forward, 
he  lays  the  load  on  the  first  man's  back, 
and  so  pressing  both  the  feet  against  the 
ground,  they  will  easily  draw  the  load. 

In  a  long  team,  where  only  one  hind 
horse  bears  on,  if  we  take  off  half  the 
number,  and  fix  them  to  a  lower  poini 
of  traction,  they  will  be  able  to  move  a 
much  greater  weight. 

Sledges  were  probably  the  first  ma- 
chines used  in  carrying  loads;  we  find 
them  thus  employed  in  Homer,  in  con- 
veying wood  for  the  funeral  pile  of  Fatro- 
clus.  There  are  some  countries  also, 
that  preserve  their  use  to  this  day.  How- 
ever, men  early  began  to  find  how  much 
more  easily  a  machine  could  be  drawn 
upon  a  rough  road  that  run  upon  wheels, 
than  one  that  thus  went  with  a  sliding 
motion.  Though  indeed,  if  all  surfaces 
were  smooth  and  even,  bodies  could  be 
drawn  with  as  much  ease  upon  a  sledge 
as  upon  wheels :  and  in  Holland,  Lap- 
land, and  other  countries,  they  use 
sledges  upon  the  smooth  surface  of  the 
ice ;  for,  as  every  surface  upon  which  we 
travel  is  usually  rough,  wheels  have  been 
made  use  of,  which  rub  less  against  the 
inequalities  than  sledges  would  do.  hi 
fact,  wheels  would  not  turn  at  all  upon 


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ke,  if  it  were  perfectly  smooth,  since  the 
cause  of  I  lie  wheels  turning  upon  a  com- 
mon road  is  the  obstacles  they  continual- 
ly meet.  For,  if  we  suppose  the  wheels 
lo  be  lifted  from  the  ground  and  carried 
along  in  the  air,  the  wheels  in  this  case 
would  not  turn  at  all,  for  there  would  be 
nothing  to  put  one  part  in  motion  rather 
than  another  ;  in  the  same  manner,  if  they 
were  carried  along  upon  perfectly  smooth 
ice,  they  would  meet  nothing  to  give  a 
beginning  to  the  rotatory  motion,  and  all 
their  parts  would  rest  equally  alike.  But, 
if  we  suppose  the  wheel  drawn  along  a 
common  road,  then  the  parts  will  receive 
unequal  obstructions,  for  it  meets  with  ob- 
stacles that  retard  it  at  bottom,  therefore 
t  he  upper  part  of  the  wheel,  which  is  not 
retarded,  will  move  more  swiftly  than  the 
lower  part,  which  is ;  but  this  it  cannot 
<to,  unless  the  wheel  moves  round.  And 
'bus  it  is,  that  the  obstacles  in  the  rough 
road  cause  this  rotatory  motion  in  the 
wheel. 

The  utility  of  wheels  arises  therefore, 
from  their  turning  upon  their  axes,  the 
resistance  arising  from  friction  being  very 
much  diminished,  and  the  draught  there- 
by rendered  more  easy ;  and  it  will  be 
found  by  experiment,  that  it  requires 
onsiderably  less  force  to  draw  a  car- 
riage when  the  wheels  are  free  to  turn 
about  their  axis,  than  when  they  are 
>  hained  together  and  cannot  turn.  A- 
eording  to  llelsbam,  a  carriage  with  four 
wheels  will  be  drawn  with  one  fifth  of  the 
effort  required  for  one  that  slides  on  the 
same  surface  in  a  sledge.  From  the  fore- 
going experiment,  it  not  only  appears 
:  hat  the  friction  is  very  much  lessened, 
but  that  this  diminution  does  not  arise 
from  the  wheels  touching  the  plane  in  a 
few  points,  but  from  their  rotation  on  their 
:txis.# 

A  sledge  passing  over  a  plane  under- 
goes a  friction,  or  rubbing  of  its  parts 
Against  the  plane  equal  to  the  distance 
through  which  it  moves ;  but  if  an  axis  be 
applied  whose  circumference  is  six 
inches,  and  on  that  a  wheel  be  placed 
whose  circumference  is  eighteen  feet,  it 
is  evident,  that  in  moving  the  carriage 
.  igbteen  feet  over  a  plane,  the  wheels  will 
make  but  one  revolution  ;  and,  as  there 
is  no  sliding  of  the  parts  between  the 
plane  and  the  wheels,  but  only  a  mere 
Hiange  of  surface,  by  one  part  of  the 
wheel  rising  and  the  other  descending 
nearly  perpendicular  to  the  plane,  no 
friction  will  take  place  there,  the  whole 
being  transferred  to  the  nave  acting  on 
the  axis;  which  nave  having  made  but 
one  revolution  in  the  same  time,  there 
has  been  only  a  sliding  of  the  parts  equal 


to  the  circumference  of  the  hole  in  the 
nave,  here  supposed  to  be  about  six 
inches,  so  that  the  friction  is  lessened 
about  as  »ne  to  thirty-six ;  besides  the 
advantage  gained  by  confining  it  to  so 
small  a  surface,  whereby  the  parts  are 
more  easily  kept  smooth  and  fitted  to 
each  other,  and  substances  applied  and 
retained  to  lessen  the  remaining  friction. 

By  the  application  of  wheels  to  a  car- 
riage, the  friction  is  lessened  in  the  pro- 
portion of  the  diameters  of  the  axis,  and 
concave  part  of  the  nave,  to  those  of  the 
wheels. 

When  a  carriage  is  drawn  up  hill,  or 
any  regular  plane  ascent  without  wheels, 
you  have  not  only  the  friction  to  over- 
come, but  the  power  must  also  be  suffi- 
cient to  overcome  that  proportion  of  the 
weight  of  the  carriage,  which  the  perpen- 
dicular part  of  the  inclined  plane  bears  to 
that  proportion  of  the  plane. 

Wheels  applied  to  a  carriage  moving 
up  a  regular  plane  of  ascent  appear  only 
to  act  as  removing  the  friction ;  for, 
though  they  may  be  considered  as  levers, 
yet,  as  each  arm  of  the  lever  is  lengthen- 
ed in  proportion  to  the  size  of  the  wheels, 
the  power  will  be  only  augmented  as  fai1 
as  the  ascent  can  be  considered  as  a  me- 
chanical power  for  raising  the  wheels, 
carriage,  &c.  to  the  top  of  the  hill. 

Large  wheels  have  the  advantage  of 
small  ones  in  overcoming  obstacles,  be- 
cause  they  act  as  levers  in  proportion  to 
their  sizes.  And  in  general  the  centre  of 
gravity  should  be  as  near  as  may  be  to  the 
axis  of  the  wheel ;  and  where  safety  is 
particularly  considered,  the  nearer  that 
centre  is  to  the  ground,  the  better. 

If  the  suspension  be  below,  and  the  bo- 
dy be  turned  forwards,  as  is  the  case 
with  two-wheeled  carriages  descending 
hills,  then  will  the  greater  part  of  the 
weight  be  thrown  before  the  axis,  and 
must  be  partly  borne  up  by  the  horse  that 
draws ;  in  ascending,  the  same  propor- 
tion will  be  thrown  backwards,  and  tend 
to  lift  the  animal.  If  the  body  be  sus- 
pended above  the  centre  of  gravity,  the 
disadvantages  will  be  equal,  but  the  ef- 
fect will  be  reversed. 

The  latest  experiments  on  this  subject 
have  been  made  by  the  Rev.  Mr.  Vince. 

Mr.  Vince,  on  Wheel  Carriages  on  plane 
hard  Ground. 
If  the  wheels  be  all  equal  and  narrow, 
it  requires  the  same  weight  to  draw  the 
carriage,  whether  it  be  loaded  before  or 
behind. 

If  broad  wheels  be  put  on,  of  the  same 
size  and  weight,  it  requires  the  same 
weight  to  draw  the  carriage  as  for  th£ 


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narrow  wheels,  at  whatever  part  it  is 
loaded. 

If*  two  wheels  be  low,  and  two  high,  it 
requires  a  greater  weight  to  draw  the 
carriage  than  when  all  are  high. 

In  this  case  it  makes  no  sensible  differ- 
ence which  go  before.  The  common  opi- 
nion, therefore,  that  the  high  wheels 
drive  on  the  lower  when  they  go  forward, 
is  not  true. 

If  the  wheels  be  all  equal,  it  requires  a 
greater  weight  to  draw  the  carriage,  the 
less  the  wheels  are. 

The  disadvantage  of  small  wl*eels  ari- 
ses from  hence,  that  the  resistance  of  the 
ground,  which  turns  the  wheels  about, 
more  easily  overcomes  the  friction  at  the 
axle  in  a  large  than  a  small  wheel,  be- 
cause it  acts  at  a  greater  distance.  For, 
the  mechanical  advantage  of  wheels  is, 
that  the  resistance  which  must  be  over- 
come by  a  force  more  than  equivalent  lo 
it,  if  the  wheels  could  not  turn,  is  over- 
come by  a  less  force  in  the  proportion  of 
the  radius  of  the  wheel,  to  the  radius  of 
the  axle,  when  the  wheels  do  turn.  Hence 
the  disadvantage  of  laying  the  load  upon 
the  low  wheels,  as  it  increases  the  fric- 
tion where  there  is  the  least  power  to 
overcome  it.  Where  the  load  is  but 
small,  and  consequently  the  friction  but 
small,  there  is  but  a  small  difference  be- 
tween the  small  and  large  wheels  ;  but 
when  the  load  is  great,  the  difference  be- 
comes considerable. 

On  hard  Ground  with  Obstacles. 
If  W  be  the  weight  of  the  carriage,  and 
the  centre  of  gravity  be  in  the  middle ; 
also  if  r  —  the  radius  of  the  wheel,  and 
x  =  the  height  of  the  obstacle,  then  the 
power  P  acting  parallel  to  the  horizon, 
which  is  just  sufficient  to  balance  the 
carriage  at  the  obstacle  without  drawing 

it  over=  1 

2r — 2x. 

For  the  power  may  be  conceived  to  be 
drawing  a  weight  up  an  inclined  plane, 
which  is  a  tangent  to  the  circle  at  the 
point  where  it  touches  the  obstacle ;  and 
as  when  that  end  rises,  the  other  rests 
upon  the  horizontal  plane,  the  power  has 
to  elevate  a  weight  only  equal  to  $  TV. 

Experiments  of  this  kind  are  subject  to 
inaccuracies  which  cannot  be  accounted 
for.  The  power  will  sometimes  hang  for 
some  time  without  moving  the  carriage, 
and  then  it  will  suddenly  draw  the  car- 
riage over  the  obstacle.  Sometimes  there 
will  be  a  difference  of  half  an  ounce  out 
of  about  ten  ounces  in  drawing  the  same 
carriage  over  the  same  obstacle,  although 
every  care  is  taken  to  have  all  the  cir- 


cumstances accurately  the  same.  Many 
of  the  experiments,  however;  answer  ve- 
ry nearly  to  the  .theory,  nor  do  any  of 
them  differ  from  it  very  materially. 

The  use  of  high  wheels  in  going  over 
obstacles  is  very  manifest  from  this  pro- 
position, and  as  carriages  are  continually 
going  over  obstacles,  high  wheels  will  al- 
ways have  the  advantage.  Moreover,  in 
sinking  into  holes,  they  have  a  double  ad- 
vantage ;  first,  they  do  not  sink  so  deep 
as  low  ones  would ;  and  secondly,  after 
sinking,  they  ascend  again  with  less  pow- 
er. As,  when  the  centre  of  gravity  is  in 
the  middle  of  the  carriage,  the  power  has 
but  half  its  weight  to  elevate  in  going 
over  an  obstacle ;  therefore,  when  the 
load  is  not  in  the  middle,  it  throws  the 
centre  of  gravity  towards  one  end,  and, 
therefore,  when  that  end  goes  over  an  ob- 
stacle, the  power  has  more  than  half  the 
weight  to  raise,  the  pressure  upon  each 
wheel  being  inversely  as  the  distance  of 
the  centre  of  gravity  from  them.  Hence, 
every  carriage  should  be  loaded  most  to- 
wards the  higher  wheels,  by  which  means 
less  than  half  the  weight  will  be  thrown 
upon  the  lower  wheels,  and  thus  each 
pair  of  wheels  may  be  made  to  require 
the  same  power  to  draw  them  over  an  ob- 
stacle. The  same  power,  however,  that 
may  be  necessary  for  one  obstacle,  will 
not  be  sufficient  fpr  another. 

If  the  height  of  the  obstacle  be  incon- 
siderable in  respect  to  the  radius  of  the 
wheel,  which  is  the  case  with  the  com- 
mon obstacles,  as  stones,  &c-  which  car- 
riages usually  meet  with,  then  P  =  JYX 

Now  as  each  pair  of  wheels  has 

the  same  obstacles  to  go  over,  x  is  given, 
and  that  P  may  be  given,  or  that  it  may 
require  the  same  power  tor  each  pair,  W 
must  vary  as  ^/r;  now  the  weight  sup- 
ported by  each  wheel  is  inversely  as  its 
distance  from  the  centre  of  gravity 
Hence,  to  overcome  small  obstacles,  the 
distance  of  the  centre  of  gravity  from  the 
great  wheels  :  its  distance  from  the 
small  :  :  the  square-root  of  the  radius  of 
the  small  wheel  :  the  square -root  of  the 
radius  of  the  large  wheel,  The  diame- 
ters of  the  wheels  of  a  common  waggon 
are  about  five  feet  eight  inches,  and  four 
feet  eight  inches,  and  the  distance  of  the 
wheels,  when  narrow,  about  six  feet  six 
inches  ;  hence  the  centre  of  gravity  of  the 
load  of  a  waggon  ought  to  be  about  three 
feet  six  inches  nearer  to  the  higher  than 
to  the  lower  wheels.  For  a  broad  wheel 
waggon,  where  the  distance  of  the  wheels 
is  about  seven  feet  ten  inches,  the  centre 
of  gravity  ought  to  be  about  four  feet 


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two  inches  nearer  to  the  higher  than  to 
the  lower. 

It  appears  also  that  when  W  svndx  are 
given,  and  x  is  very  small,  P  varies  in- 
versely as  the  square-root  of  the  radius 
of  the  wheel.  Hence  the  advantage  of  a 
wheel  to  overcome  a  small  obstacle  va- 
ries as  the  square-root  of  the  radius  of 
the  wheel.  This  resistance  of  the  obsta- 
cle causes  the  wheel  to  turn,  but  this  re- 
sistance is  not  friction  ;  the  friction  arises 
from  the  rubbing'  of  the  parts  of  one  bo- 
dy against  those  of  another,  whereas 
where  the  wheel  only  turns  upon  a  point, 
the  friction  therefore  only  takes  place  at 
the  axle,  where  the  parts  rub  one  against 
another.  There  is  therefore  no  friction  at 
the  ground,  unless  when  the  wheels  slide, 
which  is  the  case  when  they  are  chained 
together,  as  is  frequently  done  to  prevent 
them  from  running  too  fast  down  hill. 

Upon  Sand. 
It  requires  a  less  force  to  draw  a  nar- 
row than  a  broad  wheel  carriage  upon 
sand. 

The  disadvantage  of  the  broad  wheels 
seems  to  arise  from  their  driving  the 
sand  before  them. 

If  two  wheels  be  high  and  two  low,  it 
requires  a  greater  force  to  draw  the  car- 
riage than  when  all  the  wheels  are  high. 

if  all  the  wheels  be  low,  it  requires  a 
greater  force  to  draw  the  carriage  than 
in  the  last  case. 

In  all  these  cases  it  requires  less  force 
to  draw  the  carriage,  when  loaded  behind 
than  before. 

Whatever  permits  the  load  to  rise  gra- 
dually over  an  obstacle,  without  obstruct- 
ing the  velocity  of  the  carriage,  will  tend 
to' facilitate  its  draught,  and  the  applica- 
tion of  springs  has  this  effect  to  a  very 
considerable  degree  ;  the  same  weight  of 
four  pounds,  being  drawn  over  the  same 
obstacles,  when  springs  Were  put  between 
the  load  and  the  carriage,  by  four  pounds 
instead  of  fourteen.  This  remarkable  dif- 
ference, points  out  the  great  advantage 
of  springs  in  rough  roads,  an  advantage 
which  might  be  obtained  for  heavy  wag- 
gons, as  well  as  for  other  carriages,  by 
a  judicious  application  of  the  same 
means. 

Tt  appears  from  the  Memoirs  of  the 
French  Academy,  that  the  idea  of  apply- 
ing springs  to  carriages,  had  occurred  to 
M .  Thomas,  in  the  year  1703,  who  has 
given  a  drawing  of  a  carriage  construct- 
ed upon  this  principle,  many  years  before 
it  was  attempted  to  be  put  in  execution. 
So  little  expectation  had  he  of  success, 
that  he  expressly  mentions  it  as  a  theory, 
which  could  not  be  reduced  to  practice ; 


he  had,  however,  no  notion  of  applying 
springs  to  faciliate  the  draught,  but  mere- 
ly for  the  convenience  of  the  rider;  and 
1  apprehend  that  it  is  not  at  present  com- 
monly imagined,  that  springs  are  advan- 
tageous for  this  purpose  ;  nor  would  it 
at* first  sight  appear  credible,  that,  upon 
a  rough  paved  road,  such  as  are  common 
in  Cheshire,  and  other  parts  of  England, 
a  pair  of  horses  could  draw  a  carriage 
mounted  upon  springs  with  greater  ease 
and  expedition,  than  four  could  draw  the 
same  carriage,  if  the  springs  and  braces 
were  removed,  and  tli£  carriage  bolted 
fast  down  to  the  perch. 

The  reasons  why  springs  so  much  fa- 
cilitate  the  draught  of  carriages,  seems 
to  be,  not  only  that  they  allow  the  wheels 
to  pass  more  gradually  over  the  obsta- 
cles, but  that  by  their  elasticity,  they 
make  the  carriage  bound  upwards  every 
moment  for  a  small  way ;  thus  its  gravity- 
is  for  that  moment  in  a  great  measure 
counteracted,  and  the  progressive  mo 
tion  which  it  has  already  acquired,  is  at 
liberty  to  act  more  freely  in  pushing  i; 
forward ;  for  were  it  possible  very  sud- 
denly to  take  away  the  horses  from  a 
carriage  mounted  on  springs,  and  mov 
ing  with  a  considerable  velocity,  it  would 
continue  for  some  time  to  move  of  itself , 
the  weight  in  this  case  acting  as  a  fly. 
upon  any  mechanical  engine,  by  means 
of  which  the  machine  accumulates  a  cer- 
tain quantity  of  power,  and  will  keep  it- 
self in  motion  for  a  considerable  time  after 
the  hand  is  taken  away  from  it.  The 
weight  of  all  carriages,  indeed,  has  some 
effect  of  this  kind,  otherwise  the  draugh;: 
would  require  an  Intolerable  exertion  o: 
strength :  and  it  is  to  be  observed,  that 
this  tendency  to  proceed  in  the  direction 
in  which  it  is  once  set  a  going,  is  remarks 
able  in  all  great  quantities  of  matter,  and 
very  perceptible  even  when  weights  are 
pulled  directly  upwards;  for  in  raising 
great  weights  by  a  crane,  the  burden  is 
lifted  with  considerable  more  ease,  when 
near  the  top  than  at  the  bottom,  even  afuer 
making  every  necessary  allowance  for 
the  weight  of  the  rope. 

WATER. — It  is  scarcely  necessary  to 
give  any  definition  or  description  of  this 
universally  known  fluid.  It  is  a  very  trans- 
parent fluid,  possessing  a  moderate  de- 
gree of  activity,  with  regard  to  organized 
substances,  which  renders  it  friendly  to 
animal  and  vegetable  life,  for  both  which 
it  is  indeed  indispensably  necessary. — 
Hence  it  acts  but  slightly  on  the  organs 
of  sense,  and  is  therefore  said  to  have  nei- 
ther taste  nor  smell. 

Water  does  not  possess  any  considera- 
ble density.  Most  mineral  substances  are 


WAT 


WAT 


heavier  than  this  fluid,  and  among  orga- 
nized matters,  there  are  perhaps  none, 
except  oils,  and  the  products  of  art, 
which,  if  lighter  than  water,  do  not  owe 
this  property  to  their  mechanical  struc- 
ture. At  a  moderate  temperature  water 
assumes  the  solid  state,  or  freezes  ;  and 
at  a  degree  of  heat  far  below  that  requir- 
ed to  fuse,  any  of  the  simple  metals  but 
mercury,  its  internal  parts  assume  the 
elastic  state,  and  fly  oiF  with  ebullition. 
The  freezing  and  boiling  points  of  water, 


The  eolipile  is  a  copper  vessel  or  globe, 
with  a  small  apperture  on  one  side.  If 
this  be  heated  and  then  immersed  in  wa- 
ter, it  will  be  partly  filled  by  the  pressure 
of  the  atmosphere  ;  and  if  this  water  be 
then  made  to  boil,  the  steam  will  issue 
out  with  considerable  violence,  and  ex- 
cite a  fire  in  the  same  manner  as  bellows. 
This  has  been  thought  to  indicate  a  de- 
composition of  the  water  •  but  it  is  not 
the  steam  which  produces  this  effect,  but 
the  air  it  carries  with  it  bv  its  mechanical 


are  assumed  at  the  standards  for  admea-j  impulse  ;  for  if  the  nozzie  of  an  eolipile 
surements  of  heat.  See  Thermome i  er.  i  be  inserted  directly  into  the  fire,  without 


Its  weight  is  also  used  as  the  standard  !  leaving  any  space  for  the  interposition  of 


for  specific  gravities  :  see  Specific  Gra 
vity,  also  Alcohol. 

Its  capacity  for  heat  is  taken  as  the 
standard  of  the  specific  heats  of  bodies 


body  of  air,  it  will  not  excite  but  ex- 
tinguish the  fire,  as  Dr.  Lewis  proved  by 
experiment. 

Water  is  not  onlv  the  common  measure 


And  in  a  word,  the  solubility  or  insolu- :  of  specific  gravities,  but  the  tables  of  this 
bility  of  bodies  in  this  fluid,  composes  a' 
large  part  of  the  science  of  chemistry 

When  water  is  cooled  gradually,  it  con- 
tracts in  its  dimensions,  till  within  eight 
degrees  of  freezing,  and  then  expands, 
till  it  begins  to  assume  the  solid  suite. — 
Congealed  water  or  ice  is  considerably 
larger  in  its  dimensions  than  water,  upon 
which  it  therefore  floats.  The  expansion 
of  ice,  at  the  time  of  its  formation,  is  made 
with  such  force,  as  to  burst  the  strongest 
metallic  vessels.  The  assumption  of  the 
solid  state  in  water  is  effected,  hke  other 
crystallizations,  under  a  symmetrical  fi- 
gure. The  pdirts  which  become  solid  first 
by  freezing,  have  the  form  of  daggers, 
crossing  each  other  at  angles  of  60  de- 
grees. The  crystallization  of  ice  is  also 
seen  to  advantage  in  snow  and  hoar  frost, 
which  are  of  the  nature  of  the  vegeta- 
tion of  salts,  though  probably  they  may 
not  require  the  co-operation  of  light. 

Steam,  or  the  vapour  of  water,  posses- 
ses a  strong  power  of  expansion,  which 
is  greater  the  higher  its  temperature. 
This  power  has  within  the  last  century, 
been  very  advantageously  applied  to  me- 
chanical purposes.  The  vapour  of  water 
is  more  expansible  in  the  same  weight 
and  temperature,  than  air ;  whence  the 
steam  in  haif-filled  vessels,  always  occu- 
pies the  upper  place,  and  moist  air  is  less 
heavy  than  dry.  Common  air  imbibed  by 
water,  and  afterwards  expelled  again,  is 
found  to  contain  somewhat  more  of  oxy- 
gen than  before.  It  follows  therefore,  that 
the  vital  pari  of  the  atmosphere,  is  more 
disposed  to  combine  with  water  than  the 
azotic  part.  This  effect  is  remarkably 
perceived  in  fogs,  which  commonly  exhi- 
bit the  peculiar  smell  of  burned  gunpow- 
der or  nitrogen  gas  ;  and  must  be  ascrib- 
ed to  a  proportion  of  the  oxygen  having 
combined  with  the  water  of  the  fog. 


element  may  be  usefully  employed  in  the 
admeasurement  of  irregular  solids  ;  for 
one  cubic  foot  is  very  nearly  equal  to  1000 
ounces  avoirdupois.  The  numbers  of  the 
table  denoting  the  specific  gravities,  do 
therefore  denote  likewise  the  number  of 
ounces  avoirdupois,  in  a  cubic  foot  of  each 
substance. 

Native  water  is  seldom,  if  ever,  found 
perfectly  pure.  The  waters  that  flow 
within,  or  upon  the  surface  of  the  earth, 
contain  various  earthy,  saline,  metallic, 
vegetable,  or  animal  particles,  according 
to  the  substances,  over  or  through  which 
they  pass.  Main  and  snow  waters  are 
much  purer  than  these,  although  they 
also  contain  whatever  floats  in  the  air,  or 
has  been  exhaled  along  with  the  watery 
vapours. 

The  purity  of  water  may  be  known  by 
the  following  marks  of  the  properties  of 
pure  water  t 

1.  Pure  water  is  lighter  than  water 
that  is  not  pure  ;  for  not  only  the  sub- 
stances usually  dissolved  in  water,  are 
heavier  than  water,  but  also  the  specific 
gravity,  of  a  solution  of  any  ot  these  sub- 
stances in  water,  is  generally  greater  than 
the  intermediate  specific  gravity  of  the 
water,  and  of  that  substance. 

2  Pure  water  is  more  fluid  than  water 
that  is  not  pure  ;  hence  it  is  said  to  occa- 
sion a  louder  sound,  when  poured  from 
one  vessel  into  another. 

3.  It  has  no  colour,  smell  or  taste. 

4.  It  wets  more  easily  than  the  waters, 
containing  metallic  and  earthy  salts,  call- 
ed hard  waters,  and  feels  softer  when 
touched. 

5.  Soap,  or  a  solulion  of  soap  in  alco- 
hol, mrsea  easily  and  perfectly  with  it. 

6.  It  is  not  rendered  turbid  by  adding 
to  it  a  solution  of  gold  in  aqua  regia,  or 
a  solution  of  silver,  or  of  lead,  or  of  mer 


AVAT 

cury,  in  nitric  acid,  or  a  solution  of  ace- 
tate of  lead  in  water. 

The  action  of  water  upon  various  saline 
substances,  or  their  respective  solubili- 
ties, constitutes  an  object  of  great  value, 
in  the  science  of  chemistry.  This  has 
been  occasionally  shown  under  tl>e  res- 
pective articles.  But  as  these  results  may 
be  of  value  seen  all  together,  I  shall  here 
insert  three  tables  from  the  Notes  on 
Macquer's  Dictionary. 

The  following  table  shows  the  quanti- 
ties of  the  saline  substances,  that  could 
be  dissolved  in  an  ounce  of  water,  with 
the  heat  of  fifty  degrees  of  Fahrenheit's 
scale,  according  to  experiments  made  by 
Mr.  Spielmann.    Instil.  Chenme,  p.  48. 


Grains. 

Acetate  of  potash     .       .       .  470 

Salt  of  Sedlitz    .    <  .       .       .  "84 

Sulphate  of  magnesia         .       .  324 

Subcarbonate  of  potash      .       .  240 

Neutral  tartrite  of  potash          .  212 

Sulphate  of  z'mc        .       .       .  210 

Sal  gem   200 

Subcarbonate  of  soda        .       .  200 

Sal  ammoniac    ....  176 

Common  salt     ....  170 

Sulphate  of  soda        ...  168 

Salt  of  Lorraine         .       .       .  168 

Muriate  of  potash       .       •        .  160 

Tartrite  of  soda         .       .       .  137 

Sulphate  of  copper    .       .       •  124 

Sulphate  of  iron        ...  80 

Purified  nitre     ....  60 

Sal  poiychi'est  of  Glaser     .       .  40 

Sulphate  of  potash     ...  30 

Corrosive  muriate  of  mercury     ,  30 

Borax       .....  20 

Alum        .       .       .  14 

Succinc  acid      ....  5 

Arsenious  acid          ...  5 

Crude  tartar  4 

Cream  of  tartar          ...  3 


Water  when  saturated  with  one  salt  is 
capable  of  dissolving  a  considerable  por- 
tion of  another  salt ;  and  when  saturated 
With  this  also,  it  may  still  dissolve  a  third, 
a.  fourth,  or  more  suits.  Thus,  according 
to  Neumann,  four  ounces  of  water  that 
have  been  saturated  with  a  drachm  and 
h  few  grains  of  alum,  will  still  dissolve 
iive  drachms  of  nitre,  then  half  an  ounce 
of  sulphate  of  iron,  six  drachms  of  com- 
mon salt,  three  drachms  of  neutral  tar- 
trite of  potash,  and  five  drachms  of  sugar. 
In  the  same  manner  also,  four  ounces  of 
water,  saturated  with  half  an  ounce  of 
nitre,  will  dissolve  half  an  ounce  of  sul- 
phate of  zinc,  six  drachms  of  common 
salt,  six  drachms  of  sal  ammoniac,  half 
an  ounce  of  neutral  tartrite  of  potash ; 


^\AT 

and  after  all  these  an  entire  ounce  of 
sugar. 

Mr.  Eller  has  published  an  account  of 
his  experiments,  concerning  the  solutions 
of  different  salts  in  the  same  water.  See 
Mem.  of  the  Acad,  of  Berlin,  for  the  year 
1750. 

"Water  lias  long  been  considered,  as  an 
elementary  or  simple  substance.  But  the 
chemists  of  our  own  time,  in  their  re- 
searches into  the  nature  of  elastic  fluids, 
have  obtained  water  in  circumstances 
where  there  is  the  highest  reason  to  con- 
clude, that  it  is  produced  by  combination  ; 
and  in  other  experiments  its  decompo- 
sition into  two  principles,  namely,  oxy. 
gen  and  hydrogen,  is  judged  to  take 
place. 

The  powers  of  nature,  which  are  ever 
the  same,  and  are  continually  performing 
their  operations  before  us,  whether  we 
understand  them  or  not,  often  present 
facts  of  the  utmost  value  and  importance, 
which  we  overlook,  or  regard  with  indif  • 
ference.  llcnceit  happens,  that,  when  an 
enlightened  observer  makes  any  disco- 
very,  it  is  almost  always  remarked,  that 
somebody  has  seen  the  fact  before  him, or 
given  some  confused  hints  respecting  its 
theory.  It  is  evident,  however,  that  tht 
first  discoverer,  if  there  be  any  merit  in 
discovery,  is  not  the  man  who  finds  the 
treasure,  and  supposes  it  to  be  none,  bun 
he  who  is  conscious  of  its  value,  and  ap- 
plies it  to  use.  On  these  principles  it  is, 
that  the  claims  of  the  discoverers  of  the 
composition  of  water  must  be  estimated. 
The  facts  appear  to  be  as  follows  : 

Previous  to  the  month  of  October,l776, 
the  celebrated  Macouer,  assisted  by  Mr. 
Sigaud  de  la  Fond,  made  an  experiment 
by  burning  hydrogen  gas  in  a  bottle,  with- 
out explosion,  and  holding  a  white  china 
saucer  over  the  flame.  His  intention  ap- 
pears to  have  been  that  of  ascertaining 
whether  any  fuliginous  smoke  was  pro- 
duced ;  and  he  observes,  that  the  saucer 
remained  perfectly  clean  'and  white,  but 
was  moistened  with  perceptible  drops  ot 
a  clear  fluid,  resembling  water,  and 
which  in  fact  appeared  to  him  and  his 
assistant,  to  be  nothing  but  pure  water. 

In  tiie  month  of  September,  177?, 
Messrs.  Bucquet  and  Lavoisier,  not  being 
acquainted  with  the  fact,  which  is  inci- 
dently  and  concisely  mentioned  by  Mac- 
quer,  made  an  experiment  to  discover 
what  is  produced  by  the  combustion  of 
hydrogen.  They  fired  five  or  six  pints  of 
hydrogen,  in  an  open  and  wide-mouthed 
bottle,  and  instantly  poured  two  ounces 
of  iime-water  through  the  flame,  agitat- 
ing the  bottle,  during  the  time  the  com- 
bustion lasted.   The  result  of  this  expe 


WAT 


MAT 


riment  showed,  that  carbonic  acid  was 
not  produced. 

Before  the  month  of  April,  1781,  Mr. 
John  Waltire,  encouraged  by  Dr.  Priest- 
ley, fired  a  mixture  of  common  air  and 
hydrogen  gas,  in  a  close  copper  vessel, 
and  found  its  freight  diminished.  Dr. 
Priestley,  likewise,  before  the  same  pe- 
riod, fired  a  like  mixture  of  hydrogen  and 
oxygen  gas,  in  a  closed  vessel,  Mr.  Warl- 
tire  being  present.  The  inside  of  the  ves- 
sel, though  clean  and  dry  before,  became 
dewy,  and  was  lined  with  a  sooty  sub- 
stance. These  experiments  were  after- 
wards repeated  by  Mr.  Cavendish  and  Dr. 
Priestley,  and  it  was  found,  that  the  dimi- 
nution of  weight  did  not  take  place,neither 
was  the  sooty  matter  perceived.  These 
circumstances,  therefore,  must  have  ari- 
sen from  some  imperfection  in  the  appa- 
ratus or  materials,  with  which  the  former 
experiments  were  made. 

It  was  in  the  summer  of  the  year  1781, 
that  Mr.  Henry  Cavendish  was  busied  in 
examining  what  becomes  of  the  air  lost 
by  combustion,  and  made  those  valuable 
experiments,  which  were  read  before  the 
Koyal  Society  on  the  15th  of  January, 
1784.  He  burned  500,000  grain  measures 
of  hydrogen  gas,  with  about  2  J  times  the 
quantity  of  common  air,  and  by  causing 
the  burned  air  to  pass  through  a  glass 
tube  of  8  feet  in  length,  135  grains  of  pure 
water  were  condensed.  He  also  explod- 
ed a  mixture  of  19,500  grain  measures  of 
oxygen  gas,  and  37,000  of  hydrogen,  in 
a  close  vessel.  The  condensed  liquor 
was  found  to  contain  a  small  portion  of 
nitric  acid,  when  the  mixture  of  the  air 
was  such,  that  the  burned  air  still  con- 
tained a  considerable  proportion  of  oxy- 
gen. In  this  case  it  may  be  presumed, 
that  some  of  the  oxygen  combines  with  a 
portion  of  nitrogen  present.  This  great 
philosopher,  who  may  be  considered  as 
the  true  discoverer,  of  the  composition  of 
water,  appears  to  think  with  Mr.  Watt, 
that  in  those  experiments  of  Dr.  Priestley, 
w  herein  the  sulphuric  and  nitric  acids, 
seemed  to  be  converted  into  oxygen,  the 
acids  served  only  to  decompose  the  wa- 
ter, by  depriving  it  according  to  the  theo- 
ry of  that  day,  of  its  phlogistic  or  com- 
bustible part ;  but  he  thinks  it  unneces- 
sary to  r.iclude  the  consideration  of  ele- 
mentary heat,  as  Mr.  Watt  does,  because 
in  his  opinion  it  is  more  likely,  that  there 
is  no  such  thing,  and  that  the  bringing 
the  consideration  forward,  in  every  che- 
mical experiment,  in  which  increase  or 
diminution  of  heat  takes  place,  might  oc- 
casion more  trouble  and  perplexity  than 
it  is  worth. 

In  the  mean  time,  Mr.  Lavoisier  con- 


tinued his  researches,  and  during  the  win.- 
ter  of  1781,  1782,  together  with  Mr.  Gin  • 
gembre,  he  filled  a  botde  of  six  pints 
with  hydrogen,  which  being  fired,  and 
two  ounces  of  lime-water  poured  in,  w  as 
instantly  stopped  with  a  cork,  through 
which  a  flexible  yabe  communicating  with 
a  vessel  of  oxygen,  was  passed.  The  in- 
flammation ceased,  except  at  the  orifice 
of  the  tube,  through  which  the  oxygen 
was  pressed,  where  a  beautiful  flame  ap- 
peared. The  combustion  continued  a 
considerable  time,  during  which  the  lime- 
water  was  agitated  in  the  bottle.  Neither 
this,  nor  the  same  experiment  repeated 
with  pure  water,  and  with  a  weak  so- 
lution of  alkali  instead  of  lime-water, 
afforded  the  information  sought  after, 
for  these  substances  were  not  at  all  al- 
tered. 

The  inference  of  Mr.  Warltire,  respect- 
ing the  mosture  on  the  inside  of  the  glass, 
in  which  Dr.  Priestley  first  fired  hydro- 
gen and  common  air,  was,  that  these  airs 
by  combustion  deposited  the  moisture 
they  contained.  Mr.  Watt,  however,  in- 
ferred from  these  experiments,  that  wa- 
ter is  a  compound  of  the  burned  airs, 
which  has  given  out  their  latent  heat  by 
combustion,  and  communicated  his  sen- 
timents to  Dr.  Priestley,  in  a  letter  dated 
April  26,  1783,  and  he  concludes,  that  in 
every  case  where  oxygen  gas  was  pro- 
duced, water  had  been  decomposed  by 
the  use  of  some  substance,  which  had  a 
stronger  attraction  to  its  phlogiston  than 
is  possessed  by  the  oxygen  gas,  which  is 
therefore  set  at  liberty.  He  repeated 
some  experiments,  particularly  with  a 
view  to  decide  this  point ;  and  in  several 
of  them  the  quantity  of  oxygen  gas,  add- 
ed to  the  acid  which  came  over,  greatly 
exceeded  the  original  weight  of  acid  em- 
ployed. He  dissolved  magnesia,  calcare- 
ous earth,  and  minium,  respectively,  in 
pale  nitric  acid,  and  on  distilling  to  dry- 
ness, found  nearly  the  whole  of  the  nitric 
acid  in  the  retort,  highly  saturated  writh 
nitrogen.  From  common  nitre,  the  oxy- 
gen gas  was  sixteen  times  the  weight  of 
the  nitric  acid  which  wras  missing.  Mr. 
Watt  has  therefore  a  claim  to  the  merit 
of  a  discoverer,  with  regard  to  the  com- 
position of  water,  and  has  the  advantage 
of  priority,  in  the  discovery  of  its  decom- 
position. 

It  does -not  appear,  that  the  composi- 
tion of  water  was  known  or  admitted  in 
France,  till  the  summer  of  1784,  when 
Mr.  Lavoisier  and  Mr.  de  la  Place,  on  the 
24th  of  June,  repeated  the  experiment  of 
burning  hydrogen  and  oxygen  in  a  glass, 
vessel  over  mercury,  in  a  still  greater 
quantity  than  had  been  burned  by  Mr. 


WAT 


WAT 


Cavendish.  The  result  was  nearly  five 
gros  of  pure  water.  Mr.  Monge  made  a 
similar  experiment  at  Paris,  nearly  at  the 
same  time,  or  perhaps  before. 

The  theory  which  was  proposed  and 
explained  by  Mr.  Lavoisier,  wherein  such 
phenomena  as  chemists  have  usually  ac- 
t  bunted  for  by  the  disengagement  or  tran- 
sition of  phlogistion  are  explained,  mere- 
ly by  the  engagement  or  contrary  tran- 
sition of  oxygen  gas,  or  its  base,  by  him 
called  the  oxygenous  or  acidifying  princi- 
ple, and  it  received  a  great  accession  from 
the  discovery  of  the  composition  of  water. 
For  it  was  easy  to  attribute  the  hydro- 
gen, which  is  disengaged  in  many  pro- 
cesses, to  the  decomposition  of  water, 
which  is  undoubtedly  present  in  most  of 
them  ;  instead  of  supposing  it  to  come 
f  rom  such  bodies,  as  former  chemists  had 
imagined  to  contain  the  principle  of  in- 
flammability. In  the  month  of  September, 
1783,  Mr.  de  la  Place  communicated  to 
Mr.  Lavoisier,  his  thoughts  on  the  decom- 
position of  water,  which  from  Mr.  Lavoi- 
sier's former  experiments,  he  concluded 
to  take  place  in  metallic  solutions  ;  and 
these  reasons,  added  to  Mr.  Lavoiser's 
own  reflections,  induced  him  to  pursue 
the  subject  by  a  new  series  of  experi- 
ments. 

This  assiduous  and  accurate  philoso- 
pher was  the  first,  who  placed  a  quantity 
of  iron  filings,  and  pure  water  in  the  up- 
per part  of  a  vessel,  inverted  over  mercu- 
ry, and  observed,  that  the  iron  became 
oxided,  hydrogen  being  at  the  same  time 
disengaged,  the  water  being',  as  he  says, 
truly  decomposed,  lie  then  proceeded, 
in  conjunction  with  Mr.  Meusnier,  to  pass 
the  steam  of  water,  through  a  red-hot 
iron  tube,  and  found  that  the  iron  was 
oxyded,  and  hydrogen  disengaged ;  and 
the  steam  of  water  being  passed  over  a 
variety  of  other  combustible  or  oxydable 
substances,  produced  similar  results,  the 
water  disappearing,  and  hydrogen  being 
disengaged.  These  capital  experiments 
were  accounted  for  by  Mr.  Lavoisier,  by 
supposing  the  water  to  be  decomposed 
into  its  component  parts,  oxygen  and  hy- 
drogen, the  former  of  which  unites  with 
the  ignited  substance,  while  the  latter  is 
disengaged. 

The  grand  experiment  of  the  composi- 
tion of  water  by  Fourcroy,  Vauquelin  and 
Seguin,  w  as  begun  on  Wednesday,  May 
1.3,  1790,  and  was  finished  on  Friday  the 
22d  of  the  same  month.  The  combustion 
was  kept  up  185  hours  with  little  inter- 
ruption, during  which  time  the  machine 
was  not  quitted  for  a  moment.  The  ex- 
perimenters alternately  refreshed  thein- 

VOL.  II. 


selves  when  Fatigued,  by  lying  for  a  few 
hours  on  mattresses,  in  the" laboratory. 

To  obtain  the  hydrogen,  1st,  Zinc  was 
melted  and  rubbed  into  a  powder,  in  a 
very  hot  mortar.  2d.  This  metal  was  dis- 
solved in  concentrated  sulphuric  acid,  di- 
luted with  seven  parts  of  water.  The  air 
procured,  was  made  to  pass  through 
caustic  alkali.  To  obtain  the  oxygen, 
two  pounds  and  an  half  of  crystal! ized 
hvperoxymuriate  of  potash,  were  distill- 
ed, and  the  air  w.as  transferred  through 
caustic  alkali. 

Upon  the  whole,  as  the  fidelity  of  these 
philosophers,  cannot  be  suspected,  as  the 
product  of  water,  so  remarkably  coincides 
with  the  weight  of  the  air  which  was 
burned,  as  there  was  no  vestige  of  acid 
produced,  and  the  residue  of  azotic  air 
was  not  greater  than  might  be  accounted 
for,  on  the  supposition  of  original  impu- 
rity ;  the  experiment  may  be  admitted  to 
prove  that  oxygen  and  hydrogen,  in  cer- 
tain proportions,  do  unite  at  the  tempe- 
rature of  moderate  combustion,  and  form 
water.  Whether  these  principles  may 
in  any  other  proportion,  or  at  any  differ- 
ent temperature,  or  by  any  order  of  ar- 
rangement as  to  primary  and  secondary 
composition,  produce  any  other  result, 
are  circumstances  which,  for  any  thing 
we  know,  are  within  the  limits  of  possi- 
bility ;  and  it  does  not  appear  that  this 
really  happens. 

Subsequent  to  the  alleged  decompo- 
sition of  water,  by  means  of  iron,  Messrs, 
Paets  Van  Trootswyk  and  Deiman,  gave 
an  account  of  some  experiments,  by  which 
they  produced  gradually,  a  quantity  of 
air  from  water,  and  instantly  caused  it  to 
disappear.  Their  own  account  is  insert- 
ed in  the  Journal  de  Physique,  for  No- 
vember 1789.  They  filled  with  distilled 
water  a  glass  tube,  one-eighth  of  an  inch 
in  diameter,  and  twelve  inches  long,  En- 
glish measure.  One  extremity  of  this 
tube,  was  hermetically  sealed  ;  but  at  the 
time  of  sealing  a  small  gold  wire  was  in- 
serted, and  by  that  means  passed  through 
the  glass  into  the  tube,  for  the  length  of 
one  inch  and  a  half.  At  the  distance  of 
five-eighths  of  an  inch  from  the  end  of 
this  wire,  another  wire  was  placed  in  the 
tube,  which  came  out  at  the  open  end  into 
a  small  vessel  of  distilled  water,  in  winch 
that  end  was  immersed.  For  the  purpose 
of  passing  the  electric  commotion  through 
these  wires,  and  consequently  through 
the  water  between  them,  the  sealed  end 
of  the  tube  with  its  wire,  was  applied  to 
an  insulated  copper  ball,  at  a  certain  dis- 
tance from  the  prime  conductor,  of  their 
electrical  machine,  at  the  same  time  that 
3  X 


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WAT 


the  extremity  of  the  other  wire,  which 
passed  through  the  vessel  filled  with  wa- 
ter, was  made  to  communicate  with  the 
external  surface,  of  an  electrical  jar  of 
one  foot  square,  the  knob  of  which  touch- 
ed the  prime  conductor. 

When  the  electric  shock  was  passed 
through  the  water*  with  a  very  small  in- 
terval, between  the  copper  ball  and  the 
conductor,  nothing  of  consequence  hap- 
pened ;  but  when  the  distance  and  con- 
sequently the  shock  was  increased,  so 
that  the  extremity  of  each  wire,  became 
tipped  with  light,  a  great  many  of  very 
minute  bubbles  of  air,  were  produced  at 
each  commotion,  which  had  the  appear- 
ance of  a  continual  flux  between  the  two 
extremites.  This  production  of  air  was 
more  considerable,  and  the  bubbles  at. 
the  same  time  larger,  when  the  distance 
between  the  copper  ball  and  the  prime 
conductor  was  increased,  so  that  some- 
times a  small  spark  was  seen,  to  pass  from 
the  upper  wire  into  the  water.  The  air 
obtained  in  this  manner,  occupied  the  up- 
per part  of  the  tube,and  gradually  increas- 
ed in  quantity,  by  the  continuance  of  the 
process,  until  the  water  became  depress- 
ed, below  the  extremity  of  the  upper 
wire.  At  this  instant  the  electric  spark, 
which  passed  through  a  small  portion  of 
the  air,  from  the  upper  wire  to  the  water, 
set  fire  to  the  air,  precisely  in  the  same 
manner,  as  happens  with  a  mixture  of  hy- 
drogen and  oxygen,  and  the  whole  dis- 
appeared, excepting  a  very  small  residue. 
This  residue  being  taken  out,  the  experi- 
ment was  again  repeated  several  times 
with  the  same  result ;  excepting  only, 
that  the  residue  of  the  air  after  each 
inflammation  appeared  to  be  less  and  less. 

Several  chemists  found  it  difficult  to  re- 
peat this  experiment,  on  account  of  the 
facility,  with  which  the  electric  shock 
from  wires  under  water,  breaks  the  con- 
taining tube.  To  prevent  this  effect,  these 
^philosophers  were  careful,  that  the  dis- 
tance between  the  two  wires,  should  be 
too  great  for  a  spark  to  pass,  from  the 
one  to  the  other.  And  Dr.  Pearson,  be* 
fore  whom  the  experiments  were  repeated 
by  Mr.  Cuthbertson,  asserts,  that  the  dis- 
charges were  interrupted ;  by  which  word 
electricians  commonly  understand,  that 
part  of  the  circuit  is  an  imperfect  con- 
ductor. It  is  probably  of  consequence, 
that  the  stream  of  electricity  should  be 
kept  up  almost  steadily,  when  the  expan- 
sion from  the  extricated  bubbles  has  once 
been  produced.  The  plate-machine  of' 
thirty -two  inches  in  diameter,  used  by 
these  philosophers,  was  so  powerful,  as 
to  occasion  nearly  two  full  explosions 
from  a  square  foot  of  glass,  in  each  turn: 


The  smaller  shocks  here  mentioned,  musi 
therefore  have  been  extremely  numerous. 

Since  the  discovery  of  galvanism,  the 
apparent  decomposition  of  water,  has 
been  effected  by  its  means,  with  more  sin- 
gular phenomena.  If  two  wires,  about  an 
inch  distant,  be  inserted  in  a  tube  0.2  of 
an  inch  in  diameter,  and  these  wires  be 
made  to  communicate  with  the  opposite 
extremities  of  a  galvanic  pile  or  trough, 
water  in  the  tube  will  be  decomposed  ra 
pidly.  The  effect  takes  place,  even  it 
the  wires  be  several  inches  distant,  when 
the  pile  is  powerful.  But  what  is  very 
remarkable,  the  decomposition  may  bej 
effected  in  two  different  tubes,  the  wire 
from  one  extremity  of  the  pile  being 
introduced  into  one,  and  that  from  the 
opposite  extremity  into  the  other;  pro- 
vided a  communication  be  established 
by  another  wire,  or  good  conductor, 
between  the  water  in  the  two  tubes 
and  the  air  evolved  from  the  water  ii- 
one  of  the  tubes,  is  hydrogen  only,  both 
of  them  nearly  pure.  The  hydrogen 
uniformly  appears  in  the  tube,  commu- 
nicating with  what  is  commonly  con- 
sidered  as  the  negative  end  of  the  pile, 
and  the  oxygen  at  the  positive  end. 

It  has  been  asserted  by  some,  that  the 
water,  instead  of  being  decomposed  into 
oxygen  and  hydrogen,  is  converted  into 
an  acid  and  an  alkali.  This  acid  is  said 
to  be  the  muriatic,  though  some  assert  it 
to  be  the  nitric  ;  and  the  alkali  according 
to  some  is  soda. 

Dr.  Priestley  published  in  a  separate 
pamphlet,  experiments  on  the  generation 
of  air  from  water. 

Water  we  have  said,  under  the  ordina- 
ry atmospheric  pressure,  is  converted  into 
steam,  at  212°  Fahr.  of  temperature,  and 
by  so  doing,  it  expands  to  about  1800 
times  its  former  bulk  :  the  elastic  force 
which  it  thus  acquires  is  very  considera- 
ble, and  constitutes  the  moving  powei 
of  that  most  important  machine,the  steam 
engine.  Steam  readily  and  entirely  conden  - 
ses  into  water  as  it  cools,  and  it  is  in  this 
way,  that  is  by  distillation,  that  pure  wa- 
ter is  obtained  ;  for  the  most  delicate  che- 
mical uses,  the  distillation  must  be  car- 
ried on  in  glass  vessels,  and  even  with 
every  possible  precaution,  it  is  by  no 
means  easy  to  obtain  this  fluid  of  absolute 
purity. 

It  does  not  appear  that  mere  heat  is  ca- 
pable of  effecting  any  change  in  water, 
for  steam  may  be  passed  through  a  red- 
hot  glass  tube,  and  be  condensed  at  the 
other  end  again  into  pure  water. 

A  considerable  affinity  subsists  between 
water  and  atmospheric  air ;  for  if  this 
fluid  recently  distilled,  be  exposed  for  a 


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WAT 


few  days  to  the  air,  and  afterwards  be 
boiled  or  subjected  to  tbe  action  of  the 
air-pump,  a  considerable  quantity  of  bub- 
bles of  gas  will  be  disengaged  ;  there  still 
remains  a  portion  combined  with  the  wa- 
ter, which  it  is  very  difficult  to  get  rid  of, 
even  by  long  boiling. 

Oxygen  gas  is  absorbed  by  water,  in 
preference  to  atmospheric  air,  and  by 
means  of  strong  agitation  and  pressure, 
according  to  the  experiments  of  M.  Paul, 
of  Geneva,  100  cubic  inches  of  this  Huid, 
may  be  made  to  take  up  50  cubic  inches 
of  oxygen  gas,  33  cubic  inches  of  hydro- 
gen, and  66  cubic  niches  of  carburetted 
hydrogen. 

Water  is  capable  of  combining  with, 
and  dissolving  the  acids,  the  alkalies  and 
alkaline  earths,  and  all  the  compound 
salts  ;  with  several  of  these  substances 
it  unites  in  two  proportions,  forming  in 
one  case  a  solid,  and  in  the  other  case  a 
.fluid  compound;  thus  if  calcined  gypsum, 
or  barytes,  or  lime,  or  sulphat  of  soda, 
are  mixed  with  a  certain  proportion  of 
water,  the  resulting  mass  is  quite  as  solid 
as  before,  and  during  this  first  combina- 
tion, a  quantity  of  heat  is  constantly  ex- 
tricated, but  if  to  the  salts  thus  saturated 
more  water  is  added,  solution  takes  place, 
and  cold  is  generated.  From  this  solu- 
tion, the  salt  may  again  be  in  most  cases 
procured,  by  evaporating  and  cooling-,  in 
a  crystalline  form,  in  which,  though  solid, 
it  is  still  saturated  with  water:  this  pro- 
portion of  water  appears  to  be  necessary, 
to  the  crystalline  form  of  the  salt,  and 
hence  it  is  usually  called  its  water  of  crys- 
tallization ;  by  a  dry  heat  it  is  driven  off, 
and  the  salt  alone  remains  in  a  pulveru- 
lent or  amorphous  state. 


A  considerable  affinity  subsists  between 
water  and  alcohol :  if  determinate  bulks 
of  these  two  fluids  be  mixed  together, 
the  resulting  mass  will  be  found  to  have 
a  specific  gravity,  superior  to  that  of  the 
mean  of  the  ingredients,  and  a  sensible 
degree  of  heat  will  be  disengaged  during 
mixture:  there  appears  however,  to  be  no 
point  of  saturation^  which  they  will  com- 
bine together  in  all  proportions.  Resins 
and  most  other  substances  insoluble  in 
water,  but  soluble  in  alcohol,  are  precipi- 
tated from  their  solution,  by  the  addition 
of  the  former  fluid  :  as  on  the  other  hand, 
all  salts  that  are  soluble  in  water,  and  not 
in  alcohol  are  precipitated  by  means  of 
this,  from  their  watery  solution. 

Ether  and  water  are  capable  of  uniting 
in  two  different  proportions.  If  equal 
bulks  of  the  two  fluids  are  shaken  toge- 
ther, and  then  allowed  to  rest  for  a  few 
seconds,  the  mass  will  divide  into  two 
distinct  liquids,  of  which  the  upper  and 
lighter  is  ether,  holding  a  little  water,  and 
the  lower  and  denser,  is  water  combined 
with  a  little  ether. 

None  of  the  simple  combustibles  ap- 
pear to  be  soluble  in  water,  nor  have  they 
any  marked  action  on  this  fluid,  at  the 
common  temperature. 

Of  the  metallic  substances,  iron,  zinc, 
tin,  and  manganese  decompose  water  by 
the  assistance  of  h^&t,  hydrogen  gas  being 
produced,  and  the  metals  being  reduced 
to  the  state  of  oxyd.  Gold,  silver,  platina, 
and  copper  have  no  action  on  water  even 
at  a  red  heat ;  the  effect  of  the  other  me- 
tals has  not  been  examined. 

The  proportion  of  the  ingredients  that 
compose  water,  as  deduced  from  the  pre- 
ceding experiments,  are  according  to 


Lavoisier       .       .       .       15.      of  Hydrogen  to  85.    of  Oxygen 
Le  Fevre  Gineau    .       .       15.2  84.8 
Vauquelin  8c  Fourcroy    .       14.33  85  66 


Water  is  known  to  become  putrid, 
when  kept  in  casks,  as  in  sea-voyages, 
i'hls  is  owing  to  the  matter  it  takes 
up  from  the  wood,  and  may  be  prevent- 
ed by  charring  the  inside  of  the  cask. 

WATER  OF  CRYSTALLIZATION. 
Many  salts  require  a  certain  proportion 
of  water,  to  enable  them  to  retain  the 
crystalline  form,  and  this  is  called  their 
water  of  crystallization.  Some  retain 
ibis  so  feebly,  that  it  flies  off  on  exposure 
to  the  air,  and  they  fall  to  powder.  These 
are  tbe  efflorescent  salts.  Others  have 
so  great  an  affinity  for  water,  that  their 
crystals  attract  more  from  the  air,  in 


which  they  dissolve.  These  are  the  del" 
quescent. 

The  proportion  of  this  water  in  various 
salts,  likewise  differs  greatly  ;  some  hav- 
ing but  a  very  small  quantity,  others  suf- 
ficient to  hold  the  whole  of  the  salt  in 
solution,  by  the  assistance  of  heat. 

WATERS  (MINERAL.)  Theexann- 
nation  of  mineral  waters,  with  a  view  to 
ascertain  their  ingredients,  and  thence 
their  medical  qualities,  and  the  means  of 
compounding  them  artificially,  is  a  i  ob- 
ject of  considerable  importance  to  socie- 
ty. It  is  likewise  a  subject  which  de- 
serves to  be  attended  to,  because  it  af 


WAT 


WAT 


lords  no  mean  opportunity  for  the  agree 
able  practice  of  chemical  skill.  But  this 
investigation  is  more  especially  of  impor- 
tance to  the  daily  purposes  of  life,  and 
the  success  of  manufactures.  It  cannot 
but  be  an  interesting  object,  to  ascertain 
the  component  parts  and  qualities  of  the 
waters  daily  consumed  by  the  inhabitants 
of  large  towns  and  vicinities.  A  very 
minute  portion  of  unwholesome  matter, 
daily  taken,  may  constitute  the  principal 
cause,  of  the  differences  in  salubrity, 
which  are  observable  in  different  places. 
And  with  regard  to  manufactures,  it  is 
well  known  to  the  brewer,  the  paper- 
maker,  the  bleacher,  and  a  variety  of 
other  artists,  of  how  much  consequence 
it  is  to  them,  that  this  fluid  should  either 
be  pure,  or  at  least  not  contaminated  with 
such  principles,  as  tend  to  injure  the  qua- 
lities of  the  articles  they  make.  This 
analysis  has  accordingly  employed  the 
attention  of  the  first  chemists.  Bergman 
has  written  an  express  treatise  on  the 
subject,  which  may  be  found  in  the  first 
volume  of  the  English  translation  of  his 
Essays.  Fourcroy  has  written  largely  on 
this  subject.  Chaptal  in  his  Elements  of 
Chemistry,  has  given  a  very  concise  and 
perspicuous  account  of  mineral  waters, 
and  the  methods  of  examining  them.  And 
more  recently,  Kirwan  has  published  an 
octavo  volume,  on  the  analysis  of  wa- 
ters. 

The  topography  of  the  place  where 
these  waters  rise,  is  the  first  tiling  to  be 
considered.  By  examining  the  ooze  form- 
ed by  them,  and  the  earth  and  stones 
through  which  they  are  strained  and  fil- 
tered, some  judgment  may  be  formed  of 
their  contents.  In  filtering  through  the 
earth,  and  meandering  on  its  surface, 
they  take  with  them  particles  of  various 
kinds,  which  their  extreme  attenuation, 
renders  capable  of  being  suspended  in 
the  fluid,  that  serves  for  their  vehicle. — 
Hence,  we  shall  sometimes  find  in  these 
waters,  siliceous,  calcareous,  or  argilla- 
ceous earth,  and  at  other  times,  though 
less  frequently, sulphur,  magnesian  earth, 
or  from  the  decomposition  of  carbonated 
iron  ;  ochre ! 

The  following  are  the  ingredients  that 
may  occur  in  mineral  waters  : 

1.  Air  is  contained  in  by  far  the  greater 
number  of  mineral  waters  :  its  propor- 
tion does  not  exceed  one-twenty -eighth, 
of  the  bulk  of  the  water. 

2.  Oxygen  gas  was  first  detected  in 
waters  by  Scheele.  Its  quantity  is  usually 
inconsiderable  :  and  it  is  incompatible 
with  the  presence  of  sulphuretted  hydro- 
gen gas,  or  iron. 

3.  Hydrogen  gas  was  first  detected  in 


Buxton  water  by  Dr.  Pearson.  After- 
wards it  was  discovered  in  Harrowgate 
(England)  waters,  by  Dr.  Garnet,  and  in 
those  of  Lemington  Priors,  by  Mr.Lambe. 

4.  Sulphuretted  hydrogen  gas,  consti- 
tutes the  most  conspicuous  ingredient  in 
those  waters,  which  are  distinguished  by 
the  name  of  hepatic,  or  sulphureous. 

The  only  acids  hitherto  found  in  wa- 
ters, except  in  combination  with  a  base, 
are  the  carbonic,  sulphurous,  and  bo- 
racic. 

5.  Carbonic  acid  was  first  discovered 
in  Pyrmont  water,  by  Dr.  Brownrigg.  It 
is  the  most  common  ingredient  in  mine- 
ral waters,  100  cubic  inches  of  the  water, 
generally  containing  from  6  to  40  cubic 
inches  of  this  acid  gas.  According  to 
Westrumb,  100  cubic  inches  of  Pyrmont 
water,  contains  187  cubic  inches  of  it,  or 
almost  double  its  own  bulk. 

6.  Sulphureous  acid  has  been  observed 
in  several  of  the  hot  mineral  waters  in 
Italy,  which  are  in  the  neighbourhood  of 
volcanoes. 

7.  The  boracic  acid  has  also  been  ob- 
served in  some  lakes  in  Italy. 

The  only  alkali  which  has  been  observ- 
ed in  mineral  waters,  uncombincd,  is  so- 
da ;  and  the  only  earthy  bodies  are  silex 
and  lime. 

8.  Dr.  Black  delected  soda  in  the  hot 
mineral  waters  and  Geyser  and  liykum  in 
Iceland  ;  but  in  most  other  cases  the  soda 
is  combined  with  carbonic  acid. 

9.  Silex  was  first  discovered  in  waters 
by  Bergman.  It  was  afterwards  detected 
in  those  of  Geysser  and  Itykum  by  Dr. 
Black,  and  in  those  of  Carlsbad  by  Klap- 
roth.  Hassenfratz  observed  it  in  the  wa- 
ters of  Pougues,  as  Breze  did  in  those 
of  the  Pu.  It  has  been  found  also  in  many 
other  mineral  waters. 

10.  Lime  is  said  to  have  been  foumj 
uncombined  in  some  mineral  waters  ;  but 
this  has  not  been  proved  in  a  satisfactory 
manner. 

The  only  salts  hitherto  found  in  the  mi- 
neral  waters  are  the  following  sulphates, 
nitrates, muriatesjcarbonates  and  borates; 
and  of  these  the  carbonates  and  muriates 
peenr,  by  far  most  commonly,  and  the 
borates  and  nitrates  most  rarely. 

11.  Sulphate  of  soda  or  Glauber  salt, 
is  not  uncommon,  especially  in  those  mi- 
neral waters,  which  are  distinguished  by 
the  epithet  saline. 

12.  Sulphate  of  ammonia  is  found  in 
mineral  waters  near  volcanoes. 

13.  Sulphate  of  lime  is  exceedingly 
common  in  water.  Its  presence  seems  to 
have  been  first  detected  by  Dr.  Lister,  in 
1682. 

14.  Sulphate  of  magnesia  or  Epsom 


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salt,  is  almost  constantly  an  ingredient  in 
'  hose  mineral  waters  which  has  purgative 
properties.  It  was  detected  in  Epsom 
waters,  in  1610,  and  in  1696,  Dr.  Grew 
puhlished  a  treatise  on  it. 

15.  Alum  is  sometimes  found  in  mine- 
ral waters,  but  it  is  exceedingly  rare. 

16.  Sulphate  of  iron  occurs  sometimes 
in  volcanic  mineral  waters,  and  has  even 
been  observed  in  other  places. 

17.  Sulphate  of  copper,  is  only  found 
in  the  waters  which  issue  from  copper 
mines. 

18.  Nitre  has  been  found  in  some 
spring-s  in  Hungary,  but  it  is  exceedingly 
uncommon. 

19.  Nitrate  of  lime  was  first  detected 
in  water,  by  Dr.  Home  of  Edinburgh  in 
1756.  It  is  said  to  occur  in  some  springs 
in  the  sandy  deserts  of  Arabia. 

20.  Nitrate  of  magnesia  is  said  to  have 
■been  found  in  some  springs. 

21.  Muriate  of  potash  is  uncommon  ; 
but  it  has  lately  been  discovered  in  the 
mineral  springs  of  Uhleaborg  in  Sweden, 
by  Julin. 

22.  Muriate  of  soda  or  common  salt, 
is  so  extremely  common  in  mineral  wa- 
ters, that  hardly  a  single  spring"  has  been 
analized  without  detecting  some  of  it. 

23.  Muriate  of  ammonia  is  uncommon, 
but  it  has  been  found  in  some  mineral 
springs  in  Italy,  and  in  Siberia. 

24.  Muriate  of  barytes  is  still  more 
uncommon,  but  its  presence  in  mineral 
waters,  has  been  announced  by  Berg- 
man. 

25  and  26.  Muriates  of  lime  and  mag- 
nesia, are  common  ingredients. 

27-  Muriate  of  alumine  has  been  ob- 
served by  Dr.  Withering,  but  it  is  very 
uncommon. 

28.  Muriate  of  manganese  was  men- 
tioned by  Bergman,  as  sometimes  occur- 
ring in  mineral  waters.  It  has  lately  been 
detected  by  Lambe  in  the  waters  of  Le- 
mington  Priors,  but  in  an  extremely  limit- 
ed proportion. 

29.  The  presence  of  carbonate  of  pot- 
ash in  mineral  waters,  has  been  mention- 
ed by  several  chemists  :  if  it  do  occur,  it 
must  be  in  a  very  small  proportion. 

30.  Carbonate  of  soda,  is  perhaps,  one 
of  the  most  common  ingredients  of  these 
liquids,  if  we  except  common  salt  and 
carbonate  of  lime. 

31.  Carbonate  of  ammonia  has  been 
discovered  in  waters,  but  it  is  uncom- 
mon. 

32.  Carbonate  of  lime  is  found  in  al- 
most all  waters,  and  is  usually  held  in 
solution,  by  an  excess  of  acid.  It  appears 
from  the  different  experiments  of  che- 
mists, as  stated  by  Mr.  Kirwan,  and  espe- 


cially from  those  of  Berthollet,  that  wa- 
ter saturated  with  carbonic  acid,  is  capa- 
ble of  holding  in  solution,  0. 002  of  carbo- 
nate of  lime.  Now  water  saturated  witji 
carbonic  acid,  at  the  temperature  of  50° 
Fahr.  contains  very  nearly  000.2  of  its 
weight  of  carbonic  acid.  Hence  it  follows, 
that  carbonic  acid,  when  present  in  such 
quantity  as  to  saturate  waters,  is  capabk" 
of  holding  its  own  weight  of  carbonate  ot 
lime  in  solution.  Thus  we  see  1000  parts 
by  weight  of  water,  when  it  contains  two 
parts  of  carbonic  acid,  is  capable  of  dis- 
solving two  parts  of  carbonate  of  lime. 
When  the  proportion  of  water  is  increas- 
ed, it  is  capable  of  holding  the  carbonate 
of  lime  in  solution,  even  when  the  propor- 
tion of  carbonic  acid,  united  with  it,  is  di- 
minished. Thus  24.000  parts  of  water 
are  capable  of  holding  two  parts  of  car- 
bonate of  lime  in  solution,  even  whenthey 
contain  only  one  part  of  carbonic  acid. 
The  greater  the  proportion  of  water,  the 
smaller  proportion  of  carbonic  acid  is  ne 
cess-ary  to  keep  the  lime  in  solution ;  and 
when  the  water  is  increased  to  a  certain 
proportion,  no  sensible  excess  of  carbonic 
acid  is  necessary.  It  ought  to  be  remarked 
also,  that  when  water  is  increased  to  a  cer- 
tain  proportion,  no  sensible  excess  of  car- 
bonic  acid  is  necessary.  It  ought  to  be  re- 
marked further  that  water,  however  small 
a  quantity  of  carbonic  acid  it  contains,  is 
capable  of  holding  carbonate  of  lime  in 
solution,  provided  the  weight  of  the  car- 
bonic acid  present,exceedthat  of  the  lime. 
These  observations  apply  equally  to  the 
other  earthy  carbonates,  held  in  solution 
by  mineral  waters. 

33.  Carbonate  of  magnesia  is  also  very 
common  in  mineral  waters,  and  is  almost 
always  accompanied  by  carbonate  6t 
lime. 

34.  Carbonate  of  alumine.  is  said  to 
have  been  found  in  waters,  but  its  pre- 
sence has  not  been  properly  ascertained. 

35.  Carbonate  of  iron  is  by  no  means, 
uncommon,  indeed  it  forms  the  most  re- 
markable ingredient  in  these  waters, 
which  are  distinguished  by  the  epithet  ot 
chalybeate. 

36.  Borax  exists  in  some  lakes  in  Per- 
sia and  Thibet,  but  the  nature  of  these 
waters  has  not  been  ascertained. 

37  and  38.  The  hydro-sulphurets  of 
lime  and  of  soda,  have  been  frequently 
detected  in  those  waters,  which  are  call- 
ed sulphureous,  or  hepatic. 

Mr.  Westrumb  says,  that  all  sulphure- 
ous waters,  contain  more  or  less  hydro - 
sulphuret  of  lime. 

To  detect  this,  he  boiled  the  mineral 
water,  excluding  the  contact  of  atmos 
pheric  air,  to  expel  the  sulphuretted  hy- 


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drogen  gas,  and  carbonic  acid.  Into  the 
water  thus  boiled,  he  poured  sulphuric 
acid,  when  more  sulphuretted  hydrogen 
gas  was  evolved,  and  sulphateof  lime 
was  thrown  down  :  fuming  nitric  acid, 
which  separated  from  it  sulphur :  and 
oxalic  acid,  which  expelled  sulphuretted 
hydrogen,  and  formed  oxalate  of  lime 
The  water  evaporated  in  open  vessels,  let 
fall  sulphate  of  lime,  and  gave  cut  sul 
phuretted  hydrogen  gas. 

To  ascertain  the  quantity  of  sulphu 
retted  hydrogen  gas,  and  carbonic  acid, 
Mr.  We'strumfa  proceeded  as  follows 
He  introduced  thesulphureouswaterintoa 
mattras,  till  it  was  filled  to  a  certain  point, 
which  he  marked :  fitted  to  it  a  curved 
tube,  which  terminated  in  a  long  cylinder 
filled  this  cylinder  with  lime-water  for 
the  one  experiment,  and  with  acetate  o( 
lead,  with  excess  of  acid  for  the  other  ; 
luted  the  apparatus,  and  boiled  the  wa- 
ter till  no  more  gas  was  expelled.  •  When 
the  lime-water  is  used,  carbonate  of  lime 
is  precipitated  in  the  proportion  of  20 
grains  to  every  10  cubic  inches  of  carbo- 
nic acid  gas;  when  the  solution  of  ace- 
tate of  lead,  hydro-sulphuret  of  lead,  is 
thrown  down  in  the  proportion  of  19  grains 
to  10  cubic  inches  of  sulphuretted  hydro- 
gen gas. 

Another  observation,  not  less  remark- 
able, relates  to  sulphuretted  nitrogen 
gas. 

It  is  known,  that  Dr.  Gimbernat,  a 
Spanish  chemist,  asserts,  that  the  thermal 
waters  of  Aix-la-Chapelle  contain  sul- 
phuretted nitrogen  gas.^  Mr,  Schaub  too 
says,  that  he  has  obtained  it  from  the 
sulphureous  waters,  of  Nenndorf  in  Hesse- 
The  following  characters  are  ascribed  to 
this  gas  : 

1.  In  smell  it  resembles  sulphuretted 
hydrogen. 

2.  It  is  not  decomposable  by  carbonic 
acid. 

3.  It  is  not  inflammable. 

4.  It  will  not  contain  combustion. 

5.  It  is  not  decomposable  by  nitrous 
acid. 

6.  It  is  decomposed  by  concentrated 
nitric  acid,  which  separates  from  it  sul- 
phur. 

7.  It  decomposes  metallic  solutions, 
and  forms  sulphurets. 

8.  It  has  a  great  affinity  for  water, 
from  which  it  is  only  separable  by  long 
boiling. 

But  Mr.  Westrumb  has  found,  that 
sulphuretted  hydrogen  gas,  when  wash- 
ed with  milk  or  lime,  if  passed  through 
lime  diluted  with  water,  acquires  all  the 
properties  here  mentioned.  Whether  the 
sulphuretted  hydrogen  gas  be  obtained 


from  sulphureous  waters,  or  prepared 
artificially,  the  same  phenomena  take 
place.  If  the  milk  of  lime  be  taken  from 
it  by  an  acid,  sulphuretted  hydrogen  is 
disengaged,  which  is  inflammable,  and 
possesses  the  usual  properties.  Sulphu- 
retted hydrogen  gas,  therefore,  is  a  pro- 
duct of  "the  operation.  Mr.  Westrumb, 
however,  is  in  doubt,  whether  this  new 
gas  be  produced  by  the  action  of  quick- 
lime on  sulphuretted  hydrogen,  or  whe- 
ther the  sulphuretted  hydrogen  gas  con- 
tain sulph vi retted  nitrogen. 

A  third  observation,  not  less  interest- 
ing, is  the  presence  of  carbon  and  car- 
buretted  substances  in  sulphureous  mi- 
neral waters. 

Mr.  Wcstnimb  has  discovered  in  them 
a  new  principle,  a  fetid  resin  of  sulphur 
( stinkendes  schvefelharz. )  To  obtain  this 
the  sulphureous  water  must  be  evapora- 
ted in  open  vessels  and  the  residuum  dis- 
solved in  alcohol,  which  takes  up  this 
resin  and  the  earthy  muri  ts.  By  evapo- 
rating the  alcohol,  this  substance  appears 
at  first  as  a  yellowish  fat,  which  gradu- 
ally assumes  a  brown  colour,  and  be- 
comes resinous.  By  repeated  solutions 
in  alcohol  and  evaporations,  it  is  decom- 
posed into  sulphur  and  a  blackish  brown 
resin.  It  emits  a  garlic  smell,  which  be- 
comes very  strong,  and  similar  to  that  of 
assafrctida'if  water  bepoured  into  the  alco- 
holic solution.  Its  solution  acts  as  an  acid. 

The  resin  is  soluble  in  ammonia,  and 
communicates  to  it  a  yellow  colour.  This 
liquor  comports  itself  like  that  of  Beguin. 
With  lime  water  a  hydrosulphuret  is 
formed.  All  these  solutions  act  on  me- 
tallic compounds  in  the  same  manner  as 
sulphuretted  hydrogen. 

As  sulphureous  mineral  waters  arise 
from  strata  of  pitcoal,  perhaps  the  source 
of  this  bituminous  principle  may  be  traced 
to  pitcoal  itself. 

Beside  these  substances,  certain  vege 
table  and  and  animal  matters  have  been 
occasionally  observed  in  mineral  waters. 
But  in  most  cases  these  are  rather  to  be 
considered  in  the  light  of  accidental  mix- 
tures, than  of  real  component  parts  of  the 
waters  in  which  they  occur. 

From  this  synoptical  view  of  the  differ- 
ent ingredients  contained  in  mineral  wa- 
ters, it  is  evident,  that  these  substances 
occur  in  two  different  distinct  states,  viz 
1.  As  being  suspended  in  them :  and  2. 
as  being  dissolved  in  them  chiefly  in  the 
form  of  a  salt. 

The  investigation  of  mineral  water", 
consists:  1.  In  the  examination  of  them 
by  the  senses.  2.  In  the  examination  o! 
them  by  re-agents.  3.  In  the  analysis  pro- 
perly so  called. 


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The  examination  by  the  senses  consists 
in  observ  ing  the  effect  of  the  water  as  to 
appearance,  smell  and  taste. 

The  appearance  of  the  water,  the  in- 
stant in  which  it  is  pumped  out  of  the 
v. (  II,  as  well  as  after  it  has  stood  for 
sonic  lime,  affords  several  indications, 
from  which  we  are  enabled  to  form  a 
judgment  concerning  its  contents.  If  the 
water  be  turbid  at  the  well,  the  substan- 
ces are  suspended  only,  and  not  dissolv- 
ed ;  but  if  the  water  be  clear  and  trans- 
parent at  the  well,  and  some  time  inter- 
venes before  it  becomes  turbid,  the  con 
tents  are  dissolved  by  means  of  carbonic 
acid. 

The  presence  of  this  gas  is  likewise 
indicated  by  small  bubbles,  that  rise  from 
the  bottom  of  the  well,  and  burst  in  the 
air  while  they  are  making  their  escape, 
thotigh  the  water  at  the  same  time  per- 
haps has  not  an  acid  taste.  This  is  the 
case,  according  to  count  Iiazoumowski, 
with  respect  to  the  tepid  spring  in  VaU 
lais,  and  the  cold  vitriolated  chalybeate 
springs  at  Astracan.  But  the  most  evi- 
dent proof  of  a  spring  containing  carbo- 
nic acid,  is  the  generation  of  bubbles 
on  the  water  being  shaken,  and  their 
bursting  with  more  or  less  noise,  while 
the  air  is  making  its  escape. 

The  sediment  deposited  by  the  water 
in  the  well,  is  likewise  to  be  examined ; 
if  it  be  yellow,  it  indicates  the  presence  of 
iron  r  if  black,  that  of  iron  combined  with 
sulphur  ;  but  chalybeate  w  aters  being  sel- 
dom sulphuretted,  the  latter  occurs  very 
rarely.  As  to  the  colour  of  the  water  it- 
self, there  are  few  instances  where  this 
can  give  any  indication  ol'its  contents,  as 
there  are  not  many  substances  that  co- 
lour it. 

The  odour  of  the  water  serves  chiefly 
to  discover  the  presence  of  sulphuretted 
hydrogen  in  it:  such  waters  as  contain 
this  substance  have  a  peculiar  fetid  smell, 
somewhat  resembling  rotten  eggs. 

The  taste  of  a  spring',  provided  it  be 
perfectly  ascertained  by  repeated  trials, 
may  afford  some  useful  indications  with 
respect  to  the  contents.  It  may  be  made 
very  sensible  by  tasting  water,  in  which 
the  various  salts  that  are  usually  found 
in  such  waters  are  dissolved  in  various 
proportions.  There  is  no  <  ertatn  depend- 
ance, however,  to  be  plac  ;d  on  this  mode 
of  investigation  ;  for  in  many  springs  the 
taste  of  sulphate  of  soda  is  disguised  by 
that  of  the  sea  salt  united  with  it.  The 
water  too  is  not  only  to  be  tasted  at  the 
spring,  but  after  it  has  stood  for  some 
time.  This  precaution  must  be  particu- 
larly observed  with  respect  to  such  wa- 
ters as  are  impregnated  with  carbonic 


acid ;  tor  the  other  substances  contained 
in  them  make  no  impression  on  the 
tongue,  till  the  carbonic  acid  has  made 
its  escape  ;  and  it  is  for  the  same  reason, 
that  these  waters  must  be  evaporated  in 
part,  and  then  tasted  again. 

Though  the  specific  gravity  of  any 
water  contributes  but  very  little  towards 
determining  the  contents,  still  it  may  not 
be  entirely  useless  to  know  the  specific 
weight  of  the  water,  the  situation  of  the 
spring,  and  the  kind  of  sediment  deposit- 
ed by  it. 

The  examination  of  the  water  by  means 
of  reagants  shows  what  they  contain,  but 
nothow  much  of  each  principle.  In  many 
instances  this  is  as  much  as  the  inquiry 
demands;  but  it  is  always  of  use  to  di- 
rect t  he  proceedings  to  the  proper  an- 
alysis. 

It  is  absolutely  necessary  to  make  the 
experiment  with  water  just  taken  up  from 
the  spring,  and  afterwards  w  ith  such  as 
has  been  exposed  for  some  hours  to  the 
open  air  ;  and  sometimes  a  third  essay  is 
to  be  made  with  a  portion  of  the  water 
that  has  been  boiled  and  afterwards  fil- 
tered. If  the  water  contain  but  a  few 
saline  particles,  it  must  be  evaporated ; 
as  even  the  most  sensible  re-agents  do  not 
in  the  least  affect  it,  if  the  salts,  the  pre- 
sence of  which  is  to  be  discovered  by 
them,  are  diluted  with  too  great  a  quan- 
tity of  water.  Now,  it  may  happen,  that 
a  water  shall  be  impregnated  with  a  con- 
siderable number  of  saline  particles  of 
different  kinds,  though  some  of  them 
may  present  in  a  very  small  quantity :  for 
which  reason  the  water  must  be  examin- 
ed a  second  time,  after  having  been  boih 
ed  down  to  three  fourths.  For  the  analy- 
sis  of  mineral  waters  see  Tests. 

By  reagants  we  may  detect  the  presence 
of  the  different  substances  commonly 
found  in  waters,  but  as  they  are  general- 
ly combined  so  as  to  form  salts,  it  is  ne- 
cessary we  should  know  what  these 
combinations  are.  This  is  a  more  diffi- 
cult task,  which  Mr.  Kirwan  teaches  us 
to  accomplish  by  the  following  methods  : 

1.  To  ascertain  the  presence  of  the 
different  sulphats. 

The  sulphats  which  occur  in  water  are 
seven  ;  but  one  of  these,  namely,  sulphate 
of  copper,  is  so  uncommon,  that  it  may  be 
excluded  altogether.  The  same  remark 
applies  to  sulphate  of  ammonia.  It  is  al- 
most unnecessary  to  observe,  that  no 
sulphate  need  be  looked  for,  unless  both 
its  acid  and  base  have  been  previously  de- 
tected in  the  water. 

Sulphate  of  soda  may  be  detected  by 
the  following  method  :  free  the  water  to 
be  examined  of  all  earthy  sulphats,  by 


9^ 


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WAT 


evaporating  it  to  one  half,  and  adding 
lime  water  as  long  as  any  precipitate  ap- 
pears. By  these  means  the  earths  will 
all  be  precipitated  except  lime,  and  the 
only  remaining  earthy  sulphate  will  be 
sulphate  of'lime,  which  will  be  separated 
by  evaporating  the  liquid  till  it  becomes 
concentrated,  and  then  dropping  into  it  a 
little  alcohol,  and  after  filtration  adding  a 
little  oxalic  acid. 

With  the  water  thus  purified,  mix  so- 
lution  of  lime.  If  a  precipitate  appear, 
either  immediately  or  on  the  addition  of 
a  little  alcohol,  it  is  a  proof  that  sulphate 
of  potash  or  of  soda  is  present.  Which 
of  the  two  may  be  determined,  by  mixing 
some  of  the  purified  water  with  acetat  of 
barytes.  Sulphate  of  barytes  precipitates. 
Filter  and  evaporate  to  dryness.  Digest 
the  residum  in  alcohol.  It  wili  dissolve 
alkaline  acetat.  Evaporate  to  dryness, 
and  the  dry  salt  will  deliquesce  if  it  be 
acetat  of  potash,  but  effloresce  if  it  be 
acetat  of  soda. 

Sulphate  of  lime  may  be  detected,  by 
evaporating  the  water  suspected  to  con- 
tain it,  to  a  few  ounces.  A  precipitate 
appears,  which,  if  it  be  a  sulphate  of 
lime,  is  soluble  in  500  parts  of  water ; 
and  the  solution  affords  a  precipitate  with 
Lie  muriat  of  barytes,  oxalic  acid,  carbo- 
nat of  magnesia,  and  alcohol. 

Alum  may  be  detected  by  mixing  car- 
bonat of  lime  with  the  water  suspected  to 
contain  it.  If  a  precipitate  appear,  it  in- 
dicates  the  presence  of  alum,  or  at  least 
of  sulphate  of  alumine  ;  provided  the  wa- 
ter  contains  no  muriat  of  barytes,  or  me- 
tallic sulphats.  The  first  of  these  salts 
is  incompatible  with  alum.  The  second 
may  be  removed  by  the  alkaline  prussiats. 
When  a  precipitate  is  produced  in  water 
by  muriat  of  lime,  carbonat  of  lime,  and 
muriat  of  magnesia,  we  may  conclude, 
that  it  contains  alum  or  sulphate  of 
alumine. 

Sulphate  of  magnesia  may  be  detected 
by  means  of  hydrosu'.phuret  of  strontian, 
which  occasions  an  immediate  precipitate 
with  this  salt,  and  with  no  other  ;  provi- 
ded the  water  be  previously  deprived  of 
alum,  if  any  be  present,  by  means  of  car- 
bonat of  lime,  and  provided  also  that  it 
contains  no  uncombined  acid. 

Sulphate  of  iron  is  precipitated  from 
water  by  alcohol,  and  then  it  may  be 
casilv  recognized  by  its  properties. 

2  To  ascertain  the  presence  of  the  dif- 
ferent muriats. 

The  ir.uriats  found  in  waters  amount  to 
eight,  or  *o  nine,  if  muriat  of  iron  be  in- 
cluded. The  most  common  by  far,  is  mu- 
riat. ol  soda. 

Muriat  of  soda  and  of  potash  may  be 


detected  by  ahc  following  method  .  sepa- 
rate the  sulphuric  acid  by  alcohol  and 
nitrate  of  barytes.  Decompose  the  earthy 
nitrates  and  muriats,  by  adding  the  sul- 
phuric acid.  Expel  the  excess  of  muri- 
atic, and  nitric  acids  by  heat.  Separate 
the  sulphates  thus  formed  by  alcohol  and 
barytes  water.  The  water  thus  purified 
can  contain  nothing  but  alkaline  nitrats 
and  muriats.  If  it  form  a  precipitate  with 
acetat  of  silver,  we  may  conclude,  that  it 
contains  muriat  of  soda  or  of  potash.  To 
ascertain  which,  evaporate  the  liquid 
thus  precipitated  to  dryness.  Dissolve 
the  acetat  in  alcohol,  and  again  evaporate 
to  dryness.  The  salt  will  deliquesce,  if 
it  be  acetat  of  potash  ;  but  effloresce,  if  it 
be  acetat  of  soda. 

Muriat  of  barytes  may  be  detected  by 
sulphuric  acid,  as  it  is  the  only  barylic 
salt  hitherto  found  in  water. 

Muriat  of  lime  may  be  detected  by  the 
following  method :  Free  the  water  from 
sulphate  of  lime  and  other  sulphats,  by 
evaporating  it  to  a  few  ounces,  mixing  it 
with  alcohol,  and  adding  last  of  all  nitrate 
of  barytes*  as  long  as  any  preipitate  ap- 
pears. Filter  the  water  ;  evaporate  to 
dryness;  treat  the  dry  mass  with  alcohol ; 
evaporate  the  alcohol  to  dryness;  and 
dissolve  the  residum  in  water.  If  this 
solution  give  a  precipitate  with  acetat  of 
silver  and  oxalic  acid,  it  may  contain  mu- 
riat of  lime.  It  must  contain  it  in  that, 
case,  if,  after  being  treated  wi'di  carbonat 
of  lime,  it  give  no  precipitate  with  ammo  - 
nia. If  the  liquid  in  the  receiver  give  a 
precipitate  with  nitrate  of  silver,  muriat 
of  lime  existed  in  the  water. 

Muriat  of  magnesia  may  be  detected 
by  separating  all  the  sulphuric  acid  by 
means  of  nitrate  of  barytes.  Filter,  eva- 
porate to  dryness,  and  treat  the  dry  mass 
with  alcohol.  Evaporate  the  alcoholic  so- 
lution to  dryness,  and  dissolve  the  resir 
duurn  in  water.  The  muriat  of  magnesia, 
if  the  water  contained  any,  will  be  found 
in  this  solution.  Let  us  suppose  that,  by 
the  tests  formerly  described,  the  pre- 
sence of  muriatic  acid  and  of  magnesia  in 
this  solution  has  been  ascertained.  In 
that  case,  if  carbonate  of  lime  afford  no 
precipitate,  and  if  sulphuric  acid  and  eva- 
poration, together  with  the  addition  of  a 
little  alcohol,  occasion  no  precipitate,  the 
solution  contains  only  muriat  of  magne- 
sia. If  these  tests  give  precipitates,  we 
must  separate  the  lime  which  is  present 
by  sulphuric  acid  and  alcohol,  and  distil 
oil"  the  acid  with  which  it  was  combined. 
Then  the  magnesia  is  to  be  separated  by 
the  oxalic  acid  and  alcohol,  and  the  acid 
wilhwhich  it  was  united  is  to  be  distilled 
off.    If  the  liquid  in  the  retort  give  a  pre- 


WAT 


WAT 


cipitate  w  ith  nitrate  of  silver,  the  water 
contains  muriat  of  magnesia. 

iNIuriat  of  alumine  may  be  discovered 
by  saturating  the  water,  if  it  contain  an 
excess  of  alkali,  with  nitric  acid,  and  by 
separating  the  sulphuric  acid  by  means  of 
nitrate  of  barytes.  If  the  liquid  thus  pu- 
rified give  a  precipitate  with  carbonate  of 
lime,  it  contains  muriat  of  alumine.  The 
muriat  of  iron,  manganese,  if  any  be  pre- 
sent, is  also  decomposed,  and  the  iron 
precipitated  by  this  salt.  The  precipi- 
tate may  be  dissolved  to  muriatic  acid,  and 
the  alumine,  iron  and  manganese,  if  they 
be  present,  may  be  separated  by  the  rules 
laid  down  below. 

3.  To  ascertain  the  presence  of  the  dif- 
ferent nitrates.  The  nitrates  but  seldom 
occur  in  waters  ;  but  when  they  do,  they 
may  be  detected  by  the  following  re- 
sults: 

Alkaline  nitrates  may  be  detected  by 
freeing  the  water  examined  from  sulphu- 
ric acid  by  means  of  acetat  of  barytes, 
and  from  muriatic  acid  by  acetat  of  sil- 
ver. Evaporate  the  filtered  liquid,  and 
treat  the  dry  mass  with  alcohol ;  what 
the  alcohol  leaves  can  consist  only  of 
the  alkaline  nitrates  and  acetat  of  lime. 
Dissolve  it  in  water.  If  carbonate  of  mag- 
nesia occasion  a  precipitate,  lime  is  pre 
sent.  Separate  the  lime  by  means  of  car- 
bonate of  magnesia.  Filter  and  evaporate 
to  dryness,  and  treat  the  dried  mass  with 
alcohol  The  alcohol  now  leaves  only  the 
alkaiine  nitrates,  which  may  be  easily  re- 
cognised, and  distinguished  by  their  res 
pective  properties. 

Nitrate  of  lime.  To  detect  this  salt, 
concentrate  the  water,  and  mix  it  with 
alcohol  to  separate  the  sulphates.  Filter 
and  distil  off  the  alcohol ;  then  separate 
the  muriatic  acid  by  acetat  of  silver.  Fil 
ter,  evaporate  to  dryness,  and  dissolve 
the  residuum  in  alcohol.  Evaporate  to 
dryness,  and  dissolve  the  dry  mass  in  wa- 
ter* li  this  last  solution  indicate  the  pre- 
sence of  lime  by  the  usual  tests,  the  water 
contained  nitrate  of  lime. 

To  detect  nitrate  of  magnesia,  the  water 
is  to  be  freed  from  sulphate  and  muriats 
exactly  as  described  in  the  last  para- 
graph. The  liquid  thus  purified  is  to  be 
evaporated  to  dryness,  and  the  residuum 
treated  with  alcohol.  The  alcoholic  so- 
lution is  to  be  evaporated  to  dryness,  and 
the  dry  mass  dissolved  in  water.  To  this 
solution  potash  is  to  be  added,  as  long  as 
any  precipitate  appears.  The  solution 
filtered,  and  again  evaporated  to  dryness, 
is  to  be  treated  with  alcohol  If  it  leave 
a  residuum  consisting  of  nitre  (the  only 
residuum  which  it  can  leave)  the  water 
centained  nitrate  of  magnesia. 

VOL.  II. 


Such  are  the  methods,  by  which  the 
presence  of  the  different  saline  contents 
of  waters  may  be  ascertained.  The  la- 
bour of  analysis  may  be  considerably 
shortened,  by  observing  that  the  follow- 
ing salts  are  incompatible  with  each 
other,  and  cannot  exist  together  in  water, 
except  in  very  minute  proportion. 

Salts.  Incompatible  with 

ritrates  of  lime  and  mag- 
nesia. 

sulphats 


>  Muriats  of  lime  and  mag- 
t  nesia. 
C  Alkalis, 

^  Carbonat  of  magnesia, 
£  Muriat  of  barytes. 
f  Alkalis, 

j  Muriat  of  barytes, 
«(  Nitrate,  muriat,  carbonat 
j     of  lime, 

^Carbonat  of  magnesia. 
CAlkalis, 

<  Muriat  of  barytes, 
<[_ Nitrate  &  muriat  of  lime. 
CAlkalis, 

<  Muriat  of  barytes, 
C.Edrthy  Carbonats. 
CSulphates, 

<  Alkaline  carbonats, 
£  Earthy  Carbonats 

Sulphates,  except  of  lime, 
Alkaline  carbonats, 
Earthy  carbonats 
C  Alkaline  carbonats 
(_  Alkaline  sulphates 
("Alkaline  carbonats, 
J  Carbonat  of  magnesia  8c 
"j  alumine, 
^  Sulphates,  except  of  lime. 
Beside  the  substances  above  described 
there  is  sometimes  found  in  water  a  quan- 
tity of  bitumen  combined  with  alkali, 
and  in  the  state  of  soap.  In  such  waters, 
acids  occasion  a  coagulation  ;  and  the  co- 
agulum  collected  on  a  filter  discovers  its 
bituminous  nature  by  its  combustibi- 
lity. 

Water  also  sometimes  contains  ex- 
tractive matter  ;  the  presence  of  which 
may  be  detected  by  means  of  nitrate  of 
silver.  The  water  suspected  to  contain 
it  must  be  freed  from  sulphuric  and  ni- 
trie  acid  by  means  of  nitrate  of  lead  :  af- 
ter this,  if  it  give  a  brown  precipitate 
with  nitrate  of  silver,  we  may  conclude, 
that  extractive  matter  is  present. 

But  it  is  not  sufficient  to  know,  that  a 
mineral  water  contains  certain  ingredients 
it  is  necessary  to  ascertain  the  propor. 
tions  of  these,  and  thus  we  arrive  at  their 
complete  analysis 

The  proportion  of  all  the  saline  ingre- 
dients, held  in  solution  by  any  water,  may 
3  Y 


Sulphate  of 
lime 


Alum 


Sulphate  of 

magnesia 

Sulphate  of 
iron 

Muriat  of 
barytes 

Muriat  of  . 
lime 

Muriat  of 
magnesia 

Nitrate  of 
lime 


WAT 


WAT 


be  in  some  measure  estimated  from  its 
specific  gravity.  The  lighter  a  water  is 
the  less  saline  matter  does  it  contain  ;  and 
on  the  other  hand,  the  heavier  it  is,  the 
greater  is  the  proportion  of  saline  con- 
tents. Mr.  Kirwan  has  pointed  out  a 
very  ingenious  method  of  estimating  the 
saline  contents  of  a  mineral  water,  the 
specific  gravity  of  which  is  known  ;  so 
that  the  error  will  not  exceed  one  or  two 
parts  in  the  hundred.  The  method  is 
this :  Subtract  the  specific  gravity  of 
pure  water  from  the  specific  gravity  of 
the  mineral  water  examined  (both  ex- 
pressed in  whole  numbers)  and  multiply 
the  remainder  by  1-4.  The  product  is  the 
saline  contents  in  a  quantity  of  the  water 
denoted  by  the  number  employed  to  indi- 
cate the  specific  gravity  of  distilled  wa- 
ter. Thus  let  the  water  be  of  the  speci- 
fic gravity  1-079,  or  in  the  whole  numbers 
10/' 9.  Then  the  syecific  gravity  of  dis- 
tilled  water  will  be  1000.  And  1U79-1000 
X  1*4  =  110-6  the  saime  contents  in  1000 
parts  of  the  water  in  question  ;  and  con- 
sequently 11  06  in  100  parts  of  the  same 
water.  This  formula  will  often  be  of  con 
siderabie  use,  as  it  serves  as  a  kind  of 
standard,  to  which  we  may  compare  oui 
anal)  sis.  The  saline  contents  indicated 
by  it,  are  supposed  io  be  treed  from  their 
water  of  crystallization,  in  which  state 
they  ought  only  io  be  considered,  as  Mr. 
Kirwan  has  very  properly  observed,  when 
we  speak  of  the'  saline  contents  ol  a  mine- 
ral w..  er. 

Having  by  this  formula  ascertained 
pretty  near!}  the  proportion  of  saline  con- 
tends in  the"  water  examined,  and  having 
by  the  test  just  described,  determined  the 
particular  substances  that  exist  in  it,  we 
may  proceed  to  ascertain  the  proportion 
of  each  of  these  ingredients. 

1.  The  different  aerial  fluids  ought  to 
be  first  separated  and  estimated  For 
this  purpose  a  tvtort  should  be  filled  two 
thirds  with  the  water,  and  connected  with 
a  jar  full  of  mercury,  standing  over  a 
mercurial  trough  Let  the  water  be  made 
to  boil  for  a  quarter  of  an  hour.  The 
aerial  fluids  will  pass  over  into  the  jar. 
"When  the  apparatus  is  cool,  the  quantity 
ofai.  expehea  from  the  waver  ma)  be  de- 
termined either  by  bringing  the  mercury 
witl'im,  and  without  the  jar  to  a  level ;  or 
if  this  cannot  be  done,  by  reducing  the  air 
to  the  proper  density  by  calculation.  The 
air  of  the  retort  ought  to  be  carefully 
subtracted,  and  the  jar  should  be  divided 
into  cubic  inches  and  tenths 

The  only  gaseous  bodies  contained  in 
water,  are  common  air,  oxygen  gas,  ni- 
trogen gas,  carbonic  ar  id,  sulphuretted 
hydrogen  gas,  and  sulphurous  acid.  The 


last  two  never  exist  in  water  together. 
The  presence  of  either  of  them  must  be 
ascertained  previously  by  the  application 
of  the  proper  tests.  If  sulphuretted  hy- 
drogen gas  be  present,  it  will  be  mixed 
with  the  air  contained  in  the  glass  jar, 
and  must  be  separated  before  this  air  be 
examined.  For  this  purpose  the  jar  must 
be  removed  into  a  tub  of  warm  water, 
and  nitric  acid  introduced,  which  will  ab- 
sorb the  sulphuretted  hydrogen.  The 
residuum  is  then  to  be  again  put  into  a 
mercurial  jar  and  examined. 

If  the  water  contain  sulphurous  acid, 
this  previous  step  is  not  necessary.  In- 
troduce  into  the  air  a  solution  of  pure  pot- 
ash and  agitate  the  whole  gently.  The 
carbonic  acid  and  sulphurous  acid'  gas 
will  be  absorbed,  and  leave  the  other  gas- 
ses.  The  bulk  of  this  residuum  subtract- 
ed from  the  bulk  of  the  whole,  will  give 
the  bulk  of  the  carbonic  acid  and  sul- 
phurous acid  absorbed 

Evaporate  the  potash  slowly,  almost  to 
dryness,  and  leave  it  exposed  to  the  at- 
mosphere. Sulphate  of  potash  wii!  be 
formed,  which  may  be  separated  b\  dis- 
solving the  carbonat  of  potash  by  means 
of  diluted  muriatic  acid,  and  filtering  the 
solution.  100  grains  of  sulphate  of  pot- 
ash indicate  3ij  grains  of  sulphurous  acid, 
or  42  72  cubic  inches  of  that  acid  in  the 
state  of  gas.  The  bulk  of  sulphurous 
acid  gas  ascertained  by  this  method,  sub- 
tracted f;  'om  the  bulk  of  the  gas  absorb- 
ed by  the  potash,  gives  the  bulk  of  the 
carbonic  acid  gas.  Now  100  cubic  in- 
ches of  carbonic  acid,  at  the  temperature 
of  60°  and  barometer  30  inches,  weigh 
43'j93  grains.  Hence  it  is  easy  to  ascer- 
tain its  weight. 

The  gas  remaining  may  be  examined 
by  the  common  eudiometrical  processes. 

When  a  water  contains  sulphuretted 
hydrogen  gas,  the  bulk  of  this  gas  is  to 
be  ascertained  in  the  folio  •  ing  manner  - 
Fill  three  fourths  of  ajar  with  the  water 
to  be  examined,  and  invert  it  in  a  water 
trough,  and  introduce  a  little  nitrous  gas. 
This  gas,  mixing  with  the  air  in  the  up- 
per part  of  the  jar,  wiil  form  nitrous  acid, 
which  will  render  the  water  turbid,  by 
decomposing  the  sulphuretted  hydrogen 
and  precipitating  sulphur.  Continue  to 
add  nitrous  gas  at  intervals  as  long  as  red 
furnes  appear,  then  turn  up  the  jar  and 
blow  out  the  air.  If  the  hepatic  smell 
continue,  repeat  this  process.  The  sul- 
phur precipitated,  indicates  the  propor- 
tion of  hepatic  gas  in  the  water;  one 
grain  of  sulphur  indicating  the  presence 
of  3'3  >  cubic  niches  of  this  gas. 

2.  After  having  estimated  the  gaseous 
bodies,  the  next  step  is  to  ascertain  the 


WAT 

proportion  of  the  earthy  carbonats.  For 
this  purpose  it  is  necessary  to  deprive 
the  water  of  its  sulphuretted  hydrogen, 
if  it  contain  any.  This  may  be  done, 
either  by  exposing  it  to  the  air  lor  a  con- 
siderable time,  or  treating  it  with  litharge. 
A  Mifticient  quantity  of  the  water,  thus 
purified  if  necessary,  is  to  be  boiled  tor  a 
quarter  of  an  hour,  and  filtered  when 
cool.  The  earthy  carbonats  remain  on 
the  filter. 

The  precipitate  thus  obtained  may  be 
carbonat  of  lime,  of  magnesia,  of  iron,  of 
alumine,  or  even  sulphate  of  lime.  Let 
us  suppose  all  of  these  substances  to  be 
present  together.  Treat  the  mixture  with 
diluted  muriatic  acid,  which  will  dissolve 
the  whole  except  the  alumine  and  sul- 
phate of  lime.  Dry  this  residuum  in  a 
red  heat,  and  note  the  Weight.  Then 
boil  it  in  carbonat  of  soda ;  saturate  the 
soda  with  muriatic  acid,  and  boil  the 
mixture  for  half  an  hour.  Carbonat  of 
lime  and  alumine  precipitate.  Dry  this 
precipitate  and  treat  it  with  acetic  acid. 
The  lime  will  be  dissolved,  and  the  alu- 
mine will  remain.  Dry  it  and  weigh  it. 
Its  weight  subtracted  from  the  original 
weight  gives  the  proportion  of  sulphate 
of  lime. 

The  muriatic  solution  contains  lime, 
magnesia  and  iron.  Add  ammonia  as  long 
as  a  reddish  precipitate  appears.  The 
iron  and  part  of  the  magnesia  are  thus 
separated.  Dry  the  precipitate,  and  ex- 
pose it  to  the  air  for  some  time  in  a  heat 
of  200°;  then  treat  it  with  the  acetic 
acid  to  dissolve  the  magnesia,  which  so- 
lution is  to  be  added  to  the  muriatic  so 
lution.  The  iron  is  to  be  re-dissolved  in 
muriatic  acid,  precipitated  by  an  alkaline 
carbonat,  dried  and  weighed. 

Add  sulphuric  acid  to  the  muriatic  so- 
lution as  long  as  any  precipitate  appears ; 
then  heat  the  solution  and  concentrate. 
Heat  the  sulphate  of  lime  thus  obtained 
to  redness,  and  weigh  it.  luO  grains  of  it 
are  equivalent  to  70  of  carbonat  lime  dri- 
ed. Precipitate  the  magnesia  by  means 
of  carbonat  of  soda  Dry  it  and  weigh  it. 
But  as  part  remains  in  solution,  evaporate 
to  dryness,  and  wasli  the.  residuum  with 
a  sufficient  quantity  of  distilled  water,  to 
dissolve  the  muriat  of  soda  and  sulphate 
of  lime,  if  any  be  still  present.  What  re- 
mains behind  is  carbonat  of  magnesia. 
Weigh  it,  and  add  its  weight  to  the  form- 
er. The  sulphate  of  lime,  if  any,  must 
also  be  separated  and  weighed. 

3.  We  have  next  to  ascertain  the  pro- 
portion of  mineral  acids  or  alkalis,  if  any 
be  present  uncombined.  The  acids  which 
may  be  present,  omitting  the  gaseous, 
are  the  sulphuric,  muriatic  and  boracic. 


WAT 

The  proportion  of  sulphuric  acid  is 
easily  determined.  Satura  e  it  with  ba- 
rytes water,  and  ignite  the  precipitate. 
'100  grains  of  sulphate  of  barytes  thus 
formed  indicate  23  5  of  real  sulphuric 
acid. 

Saturate  the  muriatic  acid  with  bary- 
tes water,  and  then  precipitate  the  bary- 
tes by  sulphuric  acid.  One  hundred  parts 
of  the  ignited  precipitate  are  equivalent 
to  21  grains  of  real  muriatic  acid. 

Precipitate  the  boracic  acid  by  ■means 
of  acetat  of  lead.  Decompose  the  borat 
of  lead  by  boiling  it  in  sulphuric  acid. 
Evaporate  to  dryness.  Dissolve  the  bo- 
racic acid  in  alcohol,  and  evaporate  the 
solution  ;  the  acid  left  behind  may  be 
weighed. 

To  estimate  the  proportion  of  alkaline 
carbonat  present  in  a  water  containing  it, 
saturate  it  with  sulphuric  acid,  and  note 
the  weight  of  real  acid  necessary.  Now 
100  grains  of  real  sulphuric  acid  saturate 
121-48  potash,  73-32  soda. 

4.  The  alkaline  sulphate  may  be  esti- 
mated by  precipitating  their  acid  by  means 
of  nitrate  of  barytes,  having  previously 
freed  the  water  from  all  other  sulphats ; 
for  170  grains  of  ignited  sulphate  of  ba- 
rytes indicate  100  grains  of  dried  sul- 
phate of  soda ;  while  13636  grains  of  ba- 
rytes indicate  100  of  dry  sulphate  of  pot- 
ash. 

Sulphate  of  lime  is  easily  estimated  by 
evaporating  the  liquid  containing  it,  to  a 
few  ounces  (having  previously  saturated 
the  earthy  carbonats  with  nitric  acid,)  and 
precipitating  the  sulphate  of  lime  by 
means  of  weak  alcohol.  It  may  then  be 
dried  and  weighed. 

The  quantity  of  alum  may  be  estimated 
by  precipitating  the  alumine  by  carbonat 
of  lime  or  of  magnesia  (if  no  lime  be  pre- 
sent in  the  liquid.)  Twelve  grains  of  the 
alumine  heated  to  incandescence  indicate 
100  of  crystallized  alum,  or  49  of  dried 
salt. 

Sulphate  of  magnesia  may  be  estima- 
ted, provided  no  other  sulphate  be  pre- 
sent, by  precipitating  the  acid  by  means 
of  a  barytic  salt,  as  100  parts  of  ignited 
sulphate  of  barytes  indicate  52T1  of  sul- 
phate of  magnesia.  If  sulphate  of  lime, 
and  no  other  sulphate,  accompany  it,  this 
may  be  decomposed,  and  the  lime  preci- 
pitated by  carbonat  of  magnesia.  The 
weight  of  the  lime  thus  obiained  enables 
us  to  ascenain  the  quantity  of  sulph.  te  of 
lime  contained  in  the  water.  The  whole 
of  the  sulphuric  acid  is  then  to  be  preci- 
pitated by  barytes.  This  gives  the  quan- 
tity ofsuiphuiic  acid;  and  subtracting 
the  portion  which  belongs  to  the  sulphate 
of  lime,  there  remains  that  which  was 


WAT 


WAT 


combined  with  the  magnesia,  from  which 
the  sulphate  of  magnesia  may  be  easily 
estimated. 

If  sulphate  of  soda  be  present,  no 
earthy  nitrate  or  muriat  can  exist-  There- 
fore, if  no  other  earthy  sulphate  be  pre- 
sent, the  magnesia  may  be  precipitated 
by  soda,  dried  and  weighed  ;  c6  68  grains 
of  which  indicate  100  grains  of  dried  sul- 
phate of  magnesia.  The  same  process 
succeeds  when  sulphate  of  lime  accom- 
panies these  two  sulphates ;  only  in  this 
ca.se  the  precipitate,  which  consists  both 
of  lime  and  magnesia,  is  to  be  dissolved 
in  sulphuric  acid,  evaporated  to  dryness, 
and  treated  with  twice  its  weight  of  cold 
water,  which  dissolves  the  sulphate  of 
magnesia,  and  leaves  the  other  salt  Let 
the  sulphate  of  magnesia  be  evaporated  to 
dryness,  exposed  to  a  heat  of  400°  and 
weighed.  The  same  process  succeeds, 
if  alum  be  present  instead  of  sulphate  of 
lime.  The  precipitate  in  this  case,  pre- 
viously dried,  is  to  be  treated  with  acetic 
acid,  which  dissolves  the  magnesia  and 
leaves  the  alumine.  The  magnesia  may- 
be again  precipitated,  dried  and  weigh- 
ed. If  sulphate  of  iron  be  present,  it  may 
be  separated  by  exposing  the  water  to 
the  air  for  some  days,  and  mixing  with  it 
a  portion  of  alumine.  Both  the  oxide  of 
iron  and  the  sulphate  of  alumine,  thus 
formed,  precipitate  in  the  state  of  an  inso- 
luble powder.  The  sulphate  of  magne- 
sia may  then  be  estimated  by  the  rules 
above  given. 

Sulphate  of  iron  may  be  estimated  by 
precipitating  the  iron  by  means  of  prus- 
sic  alkali,  having  previously  determined 
the  weight  of  the  precipitate  produced  by 
the  prussiat  in  a  solution  of  a  given 
weight  of  sulphate  of  iron  in  water.  If 
muriat  of  iron  be  also  present,  which  is  a 
very  rare  case,  it  may  be  separated  by 
evaporating  the  water  to  dryness,  and 
treating  the  residuum  with  alcohol,  which 
dissolves  the  muriat,  and  leaves  the  sul- 
phate. 

5.  If  muriat  of  potash  or  of  soda,  with- 
out any  other  salt  exist  in  water,  we  have 
only  to  decompose  them  by  nitrate  of  sil- 
ver, and  dry  the  precipitate ;  for  217-65 
of  muriat  of  silver  indicate  100  of  muriat 
of  potash  ;  and  235  of  muriat  of  silver  in- 
dicate 100  of  common  salt. 

The  same  process  is  to  be  followed,  if 
the  alkaline  carbonats  be  present;  only 
these  carbonats  must  be  previously  satu- 
rated with  sulphuric  acid  ;  and  we  must 
precipitate  the  muriatic  acid  by  means  of 
sulphate  of  silver,  instead  of  nitrate.  The 
presence  of  sulphate  of  soda  does  not  in- 
jure the  success  of  this  process. 

If  muriat  of  ammonia  accompany  either 


of  the  fixed  alkaline  sulphats,  without 
the  presence  of  any  other  salt,  decom- 
pose the  sal  ammoniac  by  barytes  water, 
expel  the  ammonia  by  boiling,  precipi- 
tate the  barytes  by  diluted  sulphuric 
acid,  and  saturate  the  muriatic  acid  with 
soda.  The  sulphate  of  barytes  thus  pre- 
cipitated, indicates  the  quantity  of  muriat 
of  ammonia  ;  100  grains  of  sulphate  indi- 
cating 49  09  grains  of  this  salt.  If  any  sul- 
phats be  present  in  the  solution,  they 
ought  to  be  previously  separated. 

If  common  salt  be  accompanied  by  mu- 
riat of  lime,  muriat  of  magnesia,  muriat. 
of  alumine,  or  muriat  of  iron,  or  by  all 
these  together,  without  any  other  salt, 
the  earths  may  be  precipitated  by  bary- 
tes water,  and  re -dissolved  in  muriatic 
acid.  They  are  then  to  be  separated 
from  each  other  by  the  rules  formerly 
laid  down,  and  their  weight  being  deter- 
mined, indicates  the  quantity  of  every 
particular  earthy  muriat  contained  in  the 
water.  For  50  grains  of  lime  indicate  100 
of  dried  muriat  of  lime ;  30  grains  of 
magnesia  indicate  100  of  the  muriat  of 
that  earth  •  and  21  8  grains  of  alumine  in- 
dicate 100  of  the  muriat  of  alumine.  The 
barytes  is  to  be  separated  fiom  the  solu- 
tion by  sulphuric  acid,  and  the  muriatic 
acid  expelled  by  heat,  or  saturated  with 
soda;  the  common  salt  may  then  be  as- 
certained by  evaporation,  subtracting  in 
the  last  case  the  proportion  of  common 
salt,  indicated  by  the  known  quantity  of 
muriatic  acid,  from  which  the  earths  had 
been  separated. 

When  sulphats  and  muriats  exist  to- 
gether, they  ought  to  be  separated  either 
by  precipitating  the  sulphats  by  means 
of  alcohol,  or  by  evaporating  the  whole 
to  dryness,  and  dissolving  the  earthy  mu- 
riats in  alcohol.  The  salts  thus  separa- 
ted may  be  estimated  by  the  rules  already 
laid  down. 

When  alkaline  and  earthy  muriats,  and 
sulphate  of  lime  occur  together,  the  last 
is  to  be  decomposed  by  means  of  muriat 
of  barytes.  The  precipitate  ascertains 
the  weight  of  sulphate  of  lime  contained 
in  the  water.  The  estimation  is  then  to 
be  conducted  as  when  nothing  but  muri- 
ats are  present;  only  from  the  muriat  of 
lime,  that  proportion  of  muriat  must  be 
deducted,  which  is  known  to  have  been 
formed  by  the  addition  of  the  muriat  of 
barytes. 

When  muriats  of  soda,  magnesia  and 
alumine,  are  present  together  with  sul* 
phats  of  lime  and  magnesia,  the  water  to 
be  examined  ought  to  be  divided  into  two 
equal  portions.  To  the  one  portion  add 
carbonat  of  magnesia,  till  the  whole  of  the 
lime  and  alumine  is  precipitated.  Ascev- 


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tain  the  quantity  of  lime,  which  gives  the 
proportion  of  sulphate  of  lime.  Precipi- 
tate the  sulphuric  acid,  by  muriate  of 
barytes.  This  gives  the  quantity  contain- 
ed in  the  sulphate  of  magnesia,  and  sul- 
phate of  lime;  subtracting  this  last  por- 
tion, we  have  the  quantity  of  sulphate  of 
magnesia. 

From  the  second  portion  of  water,  pre- 
cipitate all  the  magnesia  and  alumine  by 
means  of  lime-water.  The  weight  of 
these  earths,  enables  us  to  ascertain  the 
weight  of  muriate  of  magnesia  and  of 
alumine  contained  in  the  water,  subtract- 
ing that  part  of  the  magnesia,  which  ex- 
isted in  the  state  of  sulphate,  as  indicated 
by  the  examination  of  the  first  portion  of 
water.  After  this  estimation,  precipitate 
the  sulphuric  acid  by  barytes  water,  and 
the  lime  by  carbonic  acid.  The  liquid 
evaporated  to  dryness,  leaves  the  com- 
mon salt. 

6.  It  now  only  remains  to  explain  the 
method  of  ascertaining  the  proportion  of 
the  nitrates  which  may  exist  in  waters. 

When  nitre  accompanies  sulphates  and 
muriates  without  any  other  nitrates,  the 
sulphates  are  to  be  decomposed  by  ace- 
tate of  barytes,  and  the  muriates  by  ace- 
tate of  silver.  The  water,  after  filtration, 
is  to  be  evaporated  to  dryness,  and  the 
residuum  treated  with  alcohol,  which  dis- 
solves the  acetates,  and  leaves  the  nitre, 
the  quantity  of  which  may  be  easily  cal- 
culated. Jf  an  alkali  be  present,  it  ought 
to  be  previously  saturated  with  sulphu- 
ric or  muriatic  acid. 

If  nitre,  common  salt,  nitrate  of  iime, 
and  muriate  of  lime  or  magnesia,  be  pre- 
sent together,  the  water  ought  to  be  eva- 
porated to  dryness,  and  the  dry  mass 
treated  with  alcohol,  which  takes  up  the 
earthy  salts.  From  the  residuum  re-dis- 
solved in  water,  the  nitre  may  be  sepa- 
rated, and  calculated  as  in  the  last  case. 
The  alcoholic  solution  is  to  be  evaporated 
to  dryness,  and  the  residuum  re-dissolv- 
ed in  water.  Let  us  suppose  it  to  contain 
muriate  of  magnesia,  nitrate  of  lime,  and 
muriate  of  lime.  Precipitate  the  muria- 
tic acid,  by  nitrate  of  silver,  which  gives 
the  proportion  of  muriate  of  magnesia  and 
of  lime.  Separate  the  magnesia  by  means 
of  carbonate  of  lime,  and  note  its  quantity. 
This  gives  the  quantity  of  muriate  of  mag- 
nesia; and  substracting  the  muriatic  acid 
contained  in  that  salt,  from  the  whole 
acid,  indicated  by  the  precipitate  of  sil- 
ver, we  have  the  proportion  of  muriate  of 
lime. 

Lastly,  saturate  the  lime  added  to  pre- 
cipitate the  magnesia,  with  nitric  acid. 
Then  precipitate  the  whole  of  the  lime, 
by  sulphuric  acid ;  and  substracting  from , 


the  whole  of  the  sulphate  thus  formed, 
that  portion  formed  by  the  carbonate  of 
lime  added,  and  by  the  lime  contained  in 
the  muriate,  the  residuum  gives  us  the 
lime  contained  in  the  original  nitrate  ; 
and  35  grains  of  lime,  form  100  of  dry- 
nitrate  of  lime. 

WATER,  MINERAL,  ARTIFICIAL. 
Mineral  waters,  exactly  in  imitation  of  the 
natural,  are  not  kept  in  the  shops  of  the 
apothecaries,  but  if  the  exact  ingredients 
in  proper  proportions  were  used,  the  imi- 
tation would  be  precise.  Hence  it  is,  that 
the  water  generally  sold,  as  the  Pyrmont, 
Seltzer,  &c.  are  variable  in  their  contents. 
We  shall  here  observe,  that  all  the  wa- 
ters, called  mineral,  as  sold  in  our  city, 
and  we  are  informed,  in  Europe,  (except 
otherwise  ordered)  contain  carbonic  acid 
gas,  or  fixed  air,  either  alone  or  combin- 
ed with  a  base,  or  mixed  with  certain  sa- 
line substances.  We  shall  first  enume- 
rate the  contents  of  those  mineral  waters, 
which  are  mostly  imitated,  and  treat  ge- 
nerally of  the  artificial. 

Aix-la-Chapelle,  see  the  latter  part  of 
this  article. 

Bath  of  Somersetshire,  England.  As  it 
comes  from  the  pump,  it  contains  a  quan- 
tity of  air,  which  rises  through  the  water 
in  the  bath,  in  large  clusters  of  bubbles, 
This  is  found  to  consist  of  equal  parts  of 
carbonic  acid  gas,  and  hydrogen  gas, 
mixed  with  a  little  atmospheric  air, 
amounting  in  the  whole  to  16  cubic  in- 
ches in  the  gallon. 

Its  solid  contents  are,  in  the  gallon, 
sulphate  of  lime  31.5  grs.,  carbonate  of 
lime  7.25  grs  ,  sulphate  of  soda  26  grs., 
muriate  of  soda  52  grs.,  silex  15.25,  oxyd, 
of  iron  0.25. 

Bordscheit,  or  Borset,  about  a  mile  and 
a  half  from  Aix-la-Chapelle,  Germany. 

One  of  the  springs  of  Borset  resembles 
those  of  Aix,  in  all  its  constituent  parts,, 
but  the  impregnation  with  sulphur  is 
much  weaker.  It  deposits  however,  some 
sulphur  in  its  course,  through  any  con- 
fined channel  on  its  upper  part,  but  not 
sufficient  to  be  worth  collecting.  It  is  pret- 
ty strongly  alkaline.  Its  temperature  is 
132°  Fahr.  which  is  nearly  as  high  as  the 
hottest  bath  at  Aix. 

The  other  hot  spring  differs  consider- 
ably from  the  former,  in  containing  no 
sulphur  in  any  form  ;  it  therefore  has  no 
smell,  nor  does  it  blacken  the  solutions 
of  silver  or  lead.  It  is,  however  equally 
alkaline,  and  the  heat  is  as  high  as  152° 
Fahr.  and  therefore  much  exceeds  the 
hottest  of  the  Aken  waters.  In  this  spring 
there  is  a  large  quantity  of  earth  suspend- 
ed, which  is  deposited  as  the  water  cools,, 
and  forms  hard  incrustations,  to  a  consi  • 


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derable  thickness  round  every  substance, 
that  may  lie  in  its  w  ay,  and  will  serve  as 
a  nucleus. 

Brighton.  The  chalybeate  spring  near 
Brighton,  commonly  called  the  Wick, 
has  long  been  noticed  as  a  ferruginous 
water. 

A  gallon  of  the  water,  according  to  Dr. 
Marcet's  analysis,  contains  sulphate  of 
iron  11.2  grs.,  sulphate  of  lime  52.72  grs., 
muriate  of  soda  12  24  grs  ,  muriate  of 
magnesia  6  grs.,  siliceous  earth  1.12  grs., 
all  dried  at  160°  Fahr.  carbonic  acid  gas 
about  18  cubic  inches,  or  one-thirteenth 
part  of  its  volume. 

Bristol,  in  Somersetshire. 

The  springs  are  known  by  the  name  of 
the  Not  Wtlls. 

The  water  at  its  origin  is  wa  m,  clear, 
pellucid  and  sparkling  ;  and  if  suffered 
to  stand  in  a  glass,  covers  its  inside  with 
small  air  bubbles.  It  has  no  smell,  and 
is  soft  and  agreeable  to  the  taste.  It 
raises  the  thermometer  to  about  seventy 
or  eighty  degrees.  It  contains  in  the  gal- 
lon 12.75  grs.  of  chalk,  7.25  of  muriate  of 
magnesia,  4  of  sea  salt,  (sulphate  of  soda) 
11.25,  sulphate  of  lime  11.75,  carbonate 
of  lime  13.5,  and  30  cubic  inches  of  car- 
bonic acid  gas 

Caroline  Baths,  at  Carlsbad  in  Bohemia, 
Germany. 

The  waters  of  this  place  are  hot.  The 
highest  temperature  is  165°  Fahr.  the 
lowest  114°. 

According  to  Klaproth  the  Sprudel  con- 
tains in  100  cubic  inches,  carbonate  of 
soda  39  grs  ,  sulphate  of  soda  70.5,  mu- 
riate of  soda  34.6,  chalk  12  grs.,  silex  2  5 
grs.,  iron  0.125  grs.,  carbonic  acid  gas  32 
cubic  inches. 

The  JVeubrunnen,  carbonate  of  soda  38.5 
grains,  sulphate  of  soda  66  75,  muriate 
of  soda  32  5,  chalk  12.4,  silex  2.5  iron 
0.125  grs.,  carbonic  acid  gas  50  cubic 
inches. 

The  Schlonsbrunnen,  carbonate  of  soda 
37.5  grains,  sulphate  of  soda  66.5  muriate 
of  soda  33,  chalk  12.75,  silex  2.125,  iron 
0.0625,  carbonic  acid  gas  fifty -three  cubic 
inches. 

Cheltenham,  in  Gloucestershire,  six 
miles  from  Gloucester,  England. 

The  gallon  contains  eight  drachms  of 
a  purging  salt,  partly  sulphate  of  soda, 
partly  sulphate  of  magnesia ;  twenty-five 
grains  of  magnesia,  part  of  which  is  unit- 
ed with  muriatic,  part  with  carbonic  acid; 
and  nearly  five  grains  of  oxide  of  iron.  It 
also  yields  30.368  cubic  inches  of  carbo- 
nic acid  gas,  and  15.184  of  a  mixture  con- 
sisting chiefly  of  nitrogen  gas,  with  a  lit- 
tle sulphuretted  hydrogen. 


Epsom,  in  Surry,  about  sixteen  miles 
from  London. 

This  water  has  never  been  analysed 
with  much  nicety.  Its  solid  contents  have 
been  made  to  amount  to  an  ounce  and  a 
half  in  the  gallon,  but  according  to  Dr. 
Lucas,  they  are  only  320  grs.  Of  these 
two-thirds  or  more  are  sulphate  of  mag- 
nesia, the  remainder  probably  muriate  of 
lime  and  magnesia,  with  sulphate  and 
carbonate  of  lime. 

Harrowgnte,  near  Knaresborough,York- 
shire,  England. 

There  are  four  springs  at  this  place, 
but  the  waters  of  all  of  them  are  nearly 
alike,  except  in  the  quantity  of  the  saline 
matter  they  contain. 

Of  the  three  old  springs,  the  highest 
gave  three  ounces  of  solid  matter  to  the 
gallon  ;  the  lowest  an  ounce  and  a  half ; 
and  the  middle  one,  only  half  an  ounce. 
Of  the  last  one  hundred  and  forty  grains 
were  earth. 

Of  the  upper,  which  alone  is  used  inter- 
nally, the  contents  are  muriate  of  soda 
6l5'6  grs.,  muriate  of  lime  13,  muriate  of 
magnesia  91,  carbonate  of  lime  18.5  car- 
bonate of  magnesia  5.5  sulphate  of  mag- 
nesia 10.5  carbonic  acid  gas  8  cubic  in- 
ches, nitrogen  gas  7,  sulphuretted  hydro- 
gen 19. 

The  water  as  it  springs  up  is  clear  and 
sparkling,  and  throws  up  a  quantity  of  air 
bubbles. 

Pyrmont,  in  Westphalia,  Germany. 

This  is  a  very  brisk  chalybeate,  abound- 
ing in  carbonic  acid ;  and  when  taken  up 
from  the  fountain,  sparkles  like  the  brisk- 
est Champaign  wine.  It  has  a  fine,  plea- 
sant, vinous  taste,  and  a  somewhat  sul- 
phureous smell.  It  is  perfectly  clear, 
and  bears  carriage  better  than  the  Spa 
water. 

A  gallon  of  it  contains  46  grains  of 
carbonate  of  lime,  15  6  of  carbonate  of 
magnesia,30  of  sulphate  of  magnesia,  10  of 
sea  salt,  2-6  of  oxyd  of  iron  ;  and  upwards 
of  200  cubic  inches  of  carbonic  acid  gas. 

Seltzer,  in  Germany. 

The  water  is  remarkably  clear  and 
light,  and  in  pouring  it  from  one  vessel 
to  another,  plenty  of  air  bubbles  arise. 

It  has,  at  first,  somewhat  of  a  brisk, 
sub-acid  pungent  taste,  but  leaves  behind 
a  lixivial  one. 

It  contains  14  grains  of  carbonate  of 
lime,  20^  of  carbonate  of  magnesia,  141.6 
of  carbonate  of  soda,  and  92  of  muriate 
of  soda,  in  the  gallon.  From  this  quan- 
tity of  the  water  128  ounce  measures  ot 
carbonic  acid  gas  were  obtained. 

Seydschutz,  in  Germany. 

It  is  situate  near  to  that  of  Sedlitz,  and 


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rs  of  the  same  purgative  nature,  but  some- 1 
what  stronger.  The  gallon  contains  of 
sulphate  of  magnesia  1620  grs.,  muriate 
of  magnesia  42  grs.,  sulphate  of  soda  33 
grs.,  sulphate  of  lime  33  grs.,  carbonate 
of  magnesia  30  grs.,  carbonate  of  lime  9 
grs.,  and  twenty-seven  cubic  inches  of  car- 
bonic acid  gas. 

Tun  bridge.  This  water  contains  in  a 
gallon,  1  grain  of  oxyd  of  iron,  muriate 
of  soda  U  5,  muriate  of  magnesia  2-25, 
sulphate  of  lime  1.25,  of  carbonic  acid 
gas  10  6  cubic  inches,  azotic  gas  4,  atmos- 
pherical air  1.4. 

Some  of  these  waters,  and  we  believe 
all,  in  Europe,  are  made  artificially.  Of 
the  mineral  waters  of  the  United  States, 
though  they  are  generally  chalybeate, 
none  exct  p\  the  Ballslown  are  artificially 
made. 

The  waters  of  Saratoga,  Bath,  Yellow 
Spring,  York,  Colestown  and  others  ot 
an  inferior  note,  ihough  resorted  to  in  the 
summer  months,  and  found  benefical  to 
the  invalid,  are  not  prepared  artificially 
as  before  observed.  We  shall  therefore 
enumerate  the  contents  of  the  latter. 

The  Saratoga  water,  according  to  Dr. 
Seaman,  p.  51,  contains  carbonic  acid, 
carbonate  of  iron,  super-carbonate  of  lime, 
muriatic  salt,  carbonated  alkali,  carbo- 
nated magnesia,  and  a  sulphureous  im- 
pregnation, and  ten  pounds  of  this  water 
consists  of  carbonic  acid  gas,  or  fixed  air 
200  cubic  inches,  carbonate  of  soda  2.6 
grs.,  muriate  of  soda,  1.73  grs.,  super  car- 
bonate of  lime  1.90  grs.,  and  carbonate  of 
lime  8£  grs. 

The  Ballstown  water,  according  to  the 
same  author,  p.  78,  contains,  carbonic 
acid,  muriate  of  soda,  carbonate  of  lime, 
carbonare  of  soda,  carbonate  of  iron,  and 
carbonate  of  magnesia.  The  imitation  of 
these  waters  was  made  by  Dr.  Seaman,  in 
the  follow  ing  manner. 

To  a  gallon  of  simple  water  in  Nooth's 
apparatus,  I  added  some  pieces  of  mar- 
ble, (carbonate  of  lime)  1384  grs.  com- 
mon salt,  and  20.8  of  carbonated  soda ; 
that  quantity  being  just  the  proportion 
obtained  from  the  mineral  water.  I  also 
suspended  ink  some  rust  of  iron,  tied  up 
in  a  linen  rag.  I  then  caused  the  air  that 
was  discharged  from  powdered  lime- 
stone, by  a  diluted  vitriolic  acid,  to  pass 
through  the  water  above-mentioned,  till 
it  appeared  to  be  fully  saturated.  To 
this  water  was  added  some  coarsely  pow- 
dered sulphur,  which  after  standing 
awhile,  was  decanted  off. 

This  liquor  was  now  acknowledged  by 
several  persons,  who  had  drank  of  the 


Saratoga  waters,  perfectly  to  resemble 
them  in  taste. 

Most  of  the  re-agents  used  on  the  na- 
tural waters,  were  repeated  on  these,  and 
with  like  effects.  Here  then  is  a  clear 
proof  of  the  success  of  the  analysis;  for 
synthesis,  or  the  re-composition  of  a  sub- 
stance, with  similar  ingredients  to  what 
were  obtained  from  it,  is  the  surest  evi- 
dence of  the  correctness  of  an  analysis. 

Notwithstanding  I  have  not  had  an  op- 
portunity of  trying  the  effects  of  this  wa- 
ter in  many  diseases,  yet  it  being  com- 
posed of  the  same  ingredients  as  the  na- 
tural waters,  leaves  no  doubt  but  that 
it  must  possess  the  same  medicinal  vir- 
tues. 

As  mineral  waters  general;)'  contain 
more  or  less  carbonic  acid,  and  as  it  is 
always  preferred,  when  combined  with 
water  as  a  beverage  ;  it  is  obvious  that 
the  manufacturers  of  these  waters  often 
super-saturate  the  water,  with  the  acid 
gas.  This  is  done  by  pressure.  The 
means  usually  emplo)ed,  consists  in  dis- 
engaging the  gas  from  chalk,  by  sulphu- 
ric acid  or  oil  of  vitriol,  receiving  it  in  a 
suitable  vessel,  and  literally  pumping  and 
forcing  it,  by  means  of  a  forcing  pump, 
into  a  turned  copper  vessel,  previously 
filled  with  water,  or  the  solution  intended 
for  saturation. 

Soda  water,  is  nothing  more  than  four 
or  more  grains  of  soda,  contained  in  a 
pint  or  more  of  water,  and  saturated  with 
carbonic  acid  ;  or  by  adding  a  solution  of 
soda,  to  the  aerated  water. 

Fourcroy,  in  his  General  System  of 
Chemical  Knowledge,  has  given  the  fol- 
lowing observations,  on  the  artificial  fa- 
brication of  mineral  waters. 

A  chemical  analysis  has  long  been  con» 
sidered  as  well  executed,  when  by  the  aid 
of  synthesis,  we  can  re-compose  the  mat- 
ter analized.  This  truth  is  applicable  to 
mineral  waters,  though  the  synthesis  of 
these,  is  to  be  classed  among  the  number 
of  things,  that  have  been  discovered  within 
a  few  j  ears.  In  fact,  we  should  not  de- 
pend on  the  accuracy  of  an  analysis  of  a 
water,  till  we  have  made  an  exact  imita- 
tion of  it,  by  dissolving  in  the  pure  fluid, 
the  same  principles  as  we  had  discovered, 
and  in  the  same  proportions,  so  that  this 
imitation  shall  exhibit  the  same  appear- 
ances on  every  trial,  and  with  every  re- 
agent, as  the  natural  water. 

Since  the  discoveries  of  the  carbonic 
acid,  and  the  great  variety  of  saline  sub- 
stances, we  have  succeeded  so  well  in 
making  accurate  analyses  of  mineral  wa- 
ters, and  consequently  in  re-composing 
them,  that  it  has  given  birth  to  a  new  art. 


WAT 


WAT 


of  no  imall  importance  to  mankind,  being 
employed  as  a  remedy  in  a  considerable 
number  of  diseases.  For  this  purpose  the 
first  thing'  to  be  done,  is  to  choose  very 
pure  spring  or  river  water,  which  con- 
tains little  or  no  foreign  matter  :  in  this, 
carbonic  acid  is  to  be  dissolved,  if  for  an 
acidulous  water,  and  then  the  salts  which 
analysis  has  shown  the  water,  we  would 
imiiate  to  contain.  If  it  be  a  chalybeate 
water  we  would  fabricate,  iron  is  to  be 
added. 

When  we  would  prepare  sulphureous 
waters,  we  saturate  water  well  boiled  and 
deprived  of  its  air,  with  sulphuretted  hy- 
drogen gas,  disengaged  from  alkaline 
sulphuret,  or  sulphuret  of  iron,  on  which, 
previously  reduced  to  powder,  is  to  be 
poured  sulphuric  or  muriatic  acid  dilut- 
ed with  water.  When  this  water  is  so 
saturated  by  means  of  gentle  agitation, 
the  salts  or  fixed  matters  we  know  to 
be  contained  in  it  are  to  be  introduced. 
In  this  imitation  we  do  not  employ  the 
inert  substances,  as  the  carbonate,  and 


sulphate  of  lime,  which  are  found  ir$ 
the  natural  water  we  would  imitate; 
we  admit  only  the  active  sapid  salts, 
which  are  taken  in  a  pure  and  crystalliz- 
ed state.  We  may  even  employ  them  in 
greater  quantity,  tnan  the  natural  water 
contains,  and  thus  prepare  waters  of  great- 
er strength,  and  more  penetrating,  than 
those  we  would  imitate. 

Bergman  has  given  the  means  of  thus 
imitaiiug  the  waters  of  Seidschutz,  Selt- 
zer, Spa,  Pyrmont,  St.  Charles  in  Bohe- 
mia, and  Aix-la-Chapelle.  The  following 
are  the  principles,  which,  conformably  ta 
his  analysis,  he  proposed  to  be  dissolved, 
to  imitate  each  of  these  mineral  waters, 
most  of  which  in  fact,  are  in  high  repute. 
In  this  table  we  shall  first  give  the  quantity 
of  the  principles  in  grains,  proportioned 
thus  by  Bergman,  to  a  quantity  of  water 
also  estimated  in  grains,  and  then  their 
proportions  in  decimal  fractions,  or  in 
thousandth  parts  of  the  water  containing 
them. 


SEIDSCHUTZ  WATER. 


Weight     .  <  . 
Specific  gravity 
Pure  air 
Carbonic  acid 
Carbonate  of  lime 
Sulphate  of  lime 
Carbonate  of  magnesia 
Sulphate  of  magnesia 
Muriate  of  magnesia 


17991  £|  grains 
1,0060 

T40^  cubic  inches 
T^5T  cubic  inches 
1  Jl  grains 
5  T\  grains 
10  |  grains 
363  grains 
7  T\-  grains 


ZT  1000 


:  0,0:5 
:  0,106 

:  0,294 

:  0,577 

120,812 

:  0,512 


SELTZER  WATER. 


Weight 
Specific  gravity 
Pure  air    .  . 
Carbonic  acid  . 
Carbonate  of  lime 
Carbonate  of  magnesia 
Carbonate  of  soda 
Muriate  of  soda 


17932  ■§§  grains 
1,0027 

■jjpg  cubic  inches 


24  cubic  inches 
7      grains  . 
12  A  grains 
10  3%  grains  . 


ZZ  46 


12 


g 


rains 


1000 

0,011 
0,910 
0,396 
0,697 
0,566 
2,684 


SPA  WATER. 


Weight  . 
Specific  gravity 
Carbonic  acid 
Carbonate  of  lime 
Carbonate  of  magnesia 
Carbonate  of  soda 


—  17902  *  grains 
zz  1,0010 

—  18  cubic  inches 

—  3  grains 

=  8  tV  grains  * 

S=  3  ||  grains  . 


zz  1000 

—  0,684 
ZZ  0,201 
ZZ  0,479 
ZZ  0,201 


WAT 


WAT 


Carbonate  of  iron 
Muriate  of  soda 


ZZ  1  $  grains 
ZZ      £  grains 


0,077 
0,023 


PYRMONT  WATER. 


Weight 

Specific  gravity 
Carbonic  acid  . 
Carbonate  of  lime 
Carbonate  oF magnesia 
Carbonate  of  iron 
Sulphate  of  lime 
Sulphate  of  magnesia 
Muriate  of  soda 


17927  &  grains 
1,0024 

37  •§  cubic  inch 

8  T7T  grains 

19  2V  grains  • 

1  ih  Srains  • 
16  T3^  grains 

10  I  grains 

2  3i  grains 


1000 


0,473 
1,063 
0,079 
0,907 
0,579 
0,165 


WATER  OF  ST.  CHARLES  IN  BOHEMIA. 


Weight  . 
Specific  gravity 
Sulphuretted  hydrogen  gas 
Carbonate  of  lime 
Carbonate  of  soda 
Sulphur  . 
Sulphate  of  soda 


ZZ  17900  grains  . 

ZZ  24  cubic  inches 

ZZ  1 0  -/f  grains 

ZZ  28  -3  grains 

ZZ  3  ~  grains 


100 


grains 


Heat  58  I 

zz  1000 

ZZ  0,442 
ZZ  0,568 
ZZ  1,585 
ZZ  0,188 
ZZ  5,593 


WATER  OF  AIX-L A-CH APELLE. 


Weight     .  . 
Specific  gravity 
Sulphuretted  hydrogen  gas 
Carbonate  of  lime 
Carbonate  of  soda 
Sulphur  .... 
Muriate  of  soda 


Lately,  art  has  gained  much  in  the  imi- 
tation of  mineral  waters,  particularly  of 
those  which  are  impregnated  with  elastic 
fluids,  and  are  indebted  to  these  for  their 
virtues.  By  the  help  of  machines,  exert- 
ing great  pressure,  water  is  made  to  im- 
bibe four,  five,  or  even  six  times  its  bulk, 
of  carbonic  acid,  so  that  art  thus  impreg- 
nates it,  with  more  than  nature  does. 
The  same  is  effected  with  sulphuretted 
hydrogen  gas,  and  even  with  oxygen  gas ; 
and  there  i#  reason  to  presume,  that  by 
this  process  will  be  formed  a  new  materia 
medica,  derived  from  the  properties  of 
elastic  fluids. 

The  saturation  of  water  with  carbonic 
acid  gas,  may  be  accomplished  in  the 
small  waj',  by  means  of  Priestley's  or 
VOL.  J  I. 


ZZ    17897  grains 


24  cubic  inches 

1 1  ||  grains 
29  I  grains 
3  T\  grains 

12  3^  grains 


ZZ  1000 

ZZ  0,443 
ZZ  0,638 
ZZ  1,655 
ZZ  0,i  88 
ZZ  0,692 


Nooth's  apparatus  ;  but  in  the  large  way, 
no  other  mode  is  used  than  the  pressure 
of  a  forcing  pump. 

We  shall  not  attempt  a  description  of 
the  apparatus  minutely,  as  it  would  be 
of  little  or  no  advantage,  and  require 
the  assistance  of  several  plates ;  but 
generally  observe,  that  the  aerated  wa- 
ters, are  made  by  impregnating  water 
with  fixed  air,  and  in  order  to  saturate 
the  fluid,  to  make  it  absorb  several  times 
its  bulk  of  air,  the  means  employed  is  a 
forcing-pump,  which  is  worked  by  differ- 
ent contrivances,  as  a  wheel,  lever,  &c. 
The  quantity  of  gas  to  be  produced,  is 
to  be  calculated  from  the  quantityof  chalk, 
marble,  or  lime-stone  employed,  always 
allowing  about  one  part  of  oil  of  vitriol. 
Z 


WAT 


AVAT 


to  two  parts  of  the  chalk,  &c.  previously 
diluting  it  with  water.  The  gas  will  be 
instantly  extricated,  and  is  then  to  be 
conveyed  by  a  pipe  into  a  vessel,  from 
Which  it  is  conducted,  and  at  the  same 
time  forced  into  a  copper  vessel,  tinned 
inside  and  containing  water,  by  a  forcing 
pump.  When  the  vessel  holding  the  aerat- 
ed water  is  removed,  and  the  necessary 
pipes  affixed;  by  turning  a  stop -cock  the 
water  will  extricate  itself  with  consider- 
able power,  producing  a  sparkling  ap- 
pearance. Although  the  discharging  pipe 
may  be  several  feet  perpendicular,  and 
the  vessel  itself  not  holding  more  than 
16  or  20  gallons,  yet  the  effect  is  such, 
that  nearly  ail  the  water  will  ascend  the 
pipe,  owing  to  the  great  pressure  of  the 
gas,  and  the  exertion  it  makes  to  obtain 
an  equilibrium.  These  remarks,  there- 
fore, on  the  manufacture  generally  of  mi- 
neral waters,  however  imperfect  they  may 
appear,  and  however  confined,  may  at 
least  be  productive  of  some  advantage, 
and  especially  lead  to  more  correct  for- 
mulae than  heretofore  adopted,  by  some 
of  the  fabricators  of  these  waters.  We 
may  however  state,  that  so  far  from  fol- 
lowing any  given  rule,  some  of  the  manu- 
facturers merely  add  the  particular  sub- 
stance, (as  soda  in  solution)  to  water  sa- 
turated with  the  gas,  without  observing 
an  uniformity,  and  so  frequently,  of  other 
waters,  which  they  would  imitate. 

WATER  COLOURS.  See  Colour 
Making. 

WATER-FILTERING-MACHINES. 
See  Filtration. 

WATER,  preservation  and  purification 

of- 

We  shall  here  give  some  general  ob- 
servations, on  the  preservation  of  water, 
as  it  is  a  subject  of  importance,  especially 
at  sea  on  long  voyages. 

It  has  been  recommended  to  add  a 
small  quantity  of  lime,  to  every  cask  of 
water.  Dr.  Butler  advises  four  ounces  of 
fine  clear  pearl-ash,  to  be  dissolved  in  100 
gallons  of  fresh  water,  and  the  cask  to  be 
closed  in  the  usual  manner. 

Dr.  Butler  relates,  that  he  put  one  oz. 
of  such  alkali,  into  a  cask  containing  25 
gallons  of  Thames-water,  and  suffered  it 
to  stand  for  upwards  of  a  year  and  a  half, 
opening  it  once  in  four  months  ;  when  he 
found  it  perfectly  sweet. 

M.  Vauquelin,  has  recommended  seve- 
ral means  of  preserving  water,  on  long 
voyages.  With  this  view,  the  inside  of 
the  casks  was  washed  with  lime-water, 
which  changed  into  calcareous  carbonate, 
and  thus  effectually  prevented  putrefac- 
tion. The  same  desirable  object  may  be 
attained,  by  adding  a  small  portion  of  vi- 


triolic acid,  and  of  alkali,  to  every  cask  ; 
which  will  preserve  the  water  in  a  pure 
and  salubrious  state,  for  at  least  twelve 
months.  Charcoal  has  also  proved  to  be 
eminently  adapted  to  such  purpose  :  the 
most  advantageous  mode  of  employing 
this  substance,  is  that  of  charring  the  in- 
ner surface  of  the  staves,  previously  to 
constructing  the  casks. 

The  latest  method  of  preserving  fresh 
water  in  a  sweet  state,  is  by  Samuel  Ben- 
tham.  It  consists  simply  in  stowing  wa- 
ter in  wooden  casks  or  tanks,  lined  with 
metallic  plates,  known  under  the  name  ot 
tinned  copper-sheets ;  the  joinings  of  such 
cases  being  carefully  soldered,  so  that 
the  water  cannot  find  the  least  access  to 
the  wood.  These  tanks  may  be  manu- 
factured of  any  shape,  adapted  to  the 
hold  of  the  ship,  and  thus  contain  any 
quantitp  of  water ;  so  that  considerable 
stowage-room  may  be  saved  on  board  ol 
vessels,  which  is  at  present  occupied  by 
the  casks. 

On  the  other  hand,  if  water  has  become 
putrid,  it  may  be  divested  of  its  pernici- 
ous properties,  by  boiling  or  by  distilla- 
tion ;  and  by  filtering  it  through  ma- 
chines described  in  the  article  Filtra- 
tion. 

To  restore  putrid  water  to  its  original 
purity,  Dr,  Lind  directs  a  small  cask,  open 
at  both  ends,  to  be  placed  within  a  larger 
vessel,  the  head  of  which  has  been  taken 
out :  clean  sand  and  gravel  are  then  to 
be  put  into  both  vessels,  so  that  the  level 
of  the  sand  in  the  inner  cask,  be  higher 
than  the  bed  in  the  intermediate  space 
between  the  two  barrels  ;  sufficient  room 
being  left  for  pouring  in  the  water.  A 
cock  should  now  be  placed  in  the  external 
cask,  above  the  gravel  or  sand ;  and  some- 
what lower  than  the  surface  of  the  mate- 
rials in  the  interior  vessel.  The  water  is 
poured  in,  at  the  top  of  the  cask  last  men- 
tioned ;  it  sinks  through  the  mass  of  sand; 
and,  after  passing  through  the  bed  in  the 
intervening  space,  it  ascends,  so  that  it 
may  be  drawn  off  perfectly  sweet  and 
clear  .-  when  the  surface  of  the  gravel  be- 
comes loaded  with  impurities,  it  should 
be  removed,  and  fresh  sand  be  substi- 
tuted. 

According  to  the  experiments  of  M. 
Lowitz,  one  and  a  half  ounces  of  pulve- 
rized charcoal,  and  24  drops  of  the  sul- 
phuric or  vitriolic  acid,  are  sufficient  to 
purify  three  and  a  half  pints  of  putrid  or 
corrupted  water,  without  communicating 
to  it  any  perceptible  acidity  :  he  directs 
the  oil  of  vitriol  to  be  first  mixed  with  the 
water ;  after  which  the  charcoal  must  be 
added ;  but,  if  the  sulphuric  acid  be  omit- 
ted, it  will  be  requisite  to  employ  a  triple 


WAT 


WAT 


portion,  or  four  and  a  half  oOnces  of  char- 
coal. When  spring-water  has  acquired 
an  unpleasant,  hepatic  flavour,  it  may  be 
greatly  improved  by  filtering  it,  through 
a  bag  with  powdered  charcoal.  This  sub- 
stance  may  again  be  dried,  and  pulveriz- 
ed, when  it  will  answer  the  same  pur- 
pose a  second  time  ;  and,  if  it  lose  its  pu- 
rifying effect,  by  repeated  use,  such  pro- 
perty may  be  recovered,  by  making  it  red- 
hot  in  a  close  vessel. 

WATER  MILLS.    £  See  Mecha- 

WATER  WHEELS. 3  nics. 

WATER  PUMP.     See  Engine  and 

IIVDUAULICS. 

WATER  BLOWING  MACHINE  — 
This  is  a  contrivance  so  formed  as  to  oc- 
casion a  blast  of  wind,  through  an  aper- 
ture at  the  top,  placed  in  a  horizontal  di- 
rection, by  the  tailing  of  water  on  a  stone, 
placed  at  the  bottom  of  the  box.  The 
water  runs  from  a  trough,  then  descends 
through  a  wooden  tube  pierced  with  a 
number  of  small  holes,  by  which  a  quan- 
tity of  air  is  taken  down  along  with  it, 
and  is  dashed  against  the  stone  placed  at 
the  bottom ;  the  water  is  thus  divided, 
the  air  is  disengaged  from  it,  and  is  press- 
ed through  the  pipe  before-mentioned, 
and  directed  on  the  burning  fuel.  While 
the  air  is  driven  in  one  direction,  the  wa- 
ter runs  out  through  an  opening  at  bot- 
tom. 

The  principal  object  in  the  construc- 
tion of  these  machines,  is  to  combine  as 
much  air  as  possible,  with  the  descend- 
ing current.  With  this  view  the  water 
is  often  made  to  pass  through  a  kind  of 
cullender,  placed  in  the  open  air,  and 
perforated  with  a  great  number  of  small 
triangular  holes.  Through  these  aper- 
tures the  water  descends  in  many  small 
streams,  and  by  exposing  a  greater  sur- 
face to  the  atmosphere,  it  carries  along 
with  it,  an  immense  quantity  of  air,  and 
is  conveyed  to  the  pedestal  by  a  tube, 
open  and  enlarged,  so  as  to  be  considera- 
bly wider  than  the  end  of  the  pipe,  which 
holds  the  cullender. 

It  has  been  generally  supposed  that 
the  water-fall  should  be  very  high,  but 
Dr.  Lewis  has  shown  by  a  variety  of  ex- 
periments, that  a  fall  of  four  or  five  feet 
is  sufficient,  and  that  when  the  height  is 
greater  than  this,  two  or  more  blowing 
machines  may  be  erected,  by  conducting 
the  water  from  which  the  air  is  extricated, 
into  another  reservoir,  from  which  it  again 
descends,  and  generates  air  as  formerly. 
That  the  air,  which  is  necessarily  loaded 
with  moisture,  may  arrive  at  the  furnace, 
in  as  dry  a  state  as  possible,  the  condens- 
ing vessel,  should  be.  as  high  as  circum- 


stances will  permit ;  and  in  order  to  de« 
termine  the  strength  of  the  blast,it  should 
be  furnished  with  a  gage  filled  with  wa- 
ter. 

Franciscus  Tertius  de  Lanis,  observes, 
that  he  has  seen  a  greater  wind  generated 
by  a  blowing  machine  of  this  kind,  than 
could  be  produced  by  bellows  10  or  12 
feet  long. 

For  a  particular  description  of  this  ma- 
chine, see  Ferguson's  Lectures.  See  also 
the  article  Trompe. 

WATER,  how  conveyed  over  hills,  val* 
leys,  l£tc. 

The  horizontal  distance  to  which  fluid 
will  spout,  from  a  horizontal  pipe,  in  any 
part  of  the  side  of  an  upright  vessel,  be- 
low the  surface  of  the  fluid,  is  equal  to 
twice  the  length  of  a  perpendicular,  to 
the  side  of  the  vessel,  drawn  from  the 
mouth  of  the  pipe,  to  a  semicircle  des- 
cribed  upon  the  altitude  of  the  fluid;  and 
therefore,  the. fluid  will  spout  to  the  great- 
est distance  possible  from  a  pipe,  whose 
mouth  is  at  the  centre  of  the  semicircle ; 
because  a  perpendicular  to  its  diameter, 
(supposed  parallel  to  the  side  of  the  ves- 
sel) drawn  from  that  point,  is  the  longest 
that  can  possibly  be  drawn  from  any  part 
of  the  diameter,  to  the  circumference  of 
the  semicircle. 

Fluids  by  their  pressure,  may  be  con- 
veyed over  hills  and  vallies,  in  bended 
pipes,  to  any  height  not  greater  than  the 
level  of  the  spring,  from  whence  they 
flow.  But  when  they  are  designed  to  be 
raised  higher  than  the  springs,  forcing 
engines  must  be  used.  See  Hydraulics. 

It  frequently  happens  that  in  the  win- 
ter-season a  supply  of  water  is  cut  off,  by 
the  congelation  of  the  water  in  the  pipes ; 
and  the  tubes  themselves  are  often  burst 
by  the  expansion  that  takes  place,  during 
the  freezing  of  the  included  water.  For 
remedying  these  inconveniencies,  Mr. 
Wright  of  Kennington,  England,  recom- 
mends the  application  of  an  air-valve,  by 
means  of  which,  the  conduit-pipes  may 
be  kept  empty,  when  there  is  no  occasion 
for  a  supply  of  water-  For  a  description 
of  this  valve,  and  for  farther  information 
upon  this  useful  subject,  we  must  refer 
the  reader  to  the  Philosophical  Magazine 
for  July  1804,  No.  74,  page  147.  English 
edition. 

WATER  PROOF.  A  term  applied  to 
certain  stuffs,  which  have  become  either 
by  a  mechanical  or  chemical  process,  im- 
pervious to  moisture. 

The  art  of  rendering  cloth  impermea 
ble  to  water,  has  lately  been  practised  to 
some  extent.  Vauquclin  says,  that  a  fluid 
effectual  for  this  purpose,  may  be  made 


WAT 


WAT 


by  dissolving  soap  and  glue,  in  water ; 
adding  a  solution  of  alum,  which  will  oc- 
casion a  flocculent  precipitate :  and  then 
mixing  with  it  a  little  dilute  sulphuric 
acid,  which  re-dissolves  the  alumine  in 
part,  renders  the  precipitate  lighter,  and 
prevents  it  from  falling  down.  He  does 
not  give  the  proportions,  but  observes, 
that  there  must  not  be  too  much  acid. 

The  Chinese  employ  the  following  sim- 
ple process,  for  rendering  cloth  water- 
proof. 

Let  an  ounce  of  white  wax  be  dissolv- 
ed in  one  quart  of  spirit  of  turpentine  ; 
the  cloth  be  immersed  in  the  solution, 
and  then  suspended  in  the  air,  till  it  be 
perfectly  dry.  B>  this  method  the  most 
open  muslin,  as  well  as  the  strongest 
cloths,  may  be  rendered  impenetrable  to 
the  heaviest  snowers;  nor  will  such  com- 
position fill  up  the  interstices  of  the  finest 
lawn  ;  or  in  the  least  degree  afj'ect  the 
most  brilliant  colours. 

We  shall  now  enumerate  several  pa- 
tents, which  have  been  granted  in  Eu- 
rope, for  the  same  purpose. 

In  July,  1797,  a  patent  was  granted  to 
Mr.  Henry  Johnson,  for  his  invention  of  a 
vegetable  liquid,  the  design  of  which  is 
to  bleach  and  cleanse  woollen,  or  other 
stuffs  ;  to  prepare  them  for  the  recep- 
tion of  a  certain  compound,  calculated 
to  render  them  not  only  water-proof, 
but  also  more  durable  and  elastic,  when 
manufactured  into  articles  of  dress, 
which  he  terms  Hydrolaines.  In  order 
to  obtain  first  the  vegetable  liquid,  the 
patentee  directs  horse  chesnuts,  or  the 
rinds  and  kernels  of  oranges,  that  are 
usually  thrown  away,  or  the  offals  and 
gall  of  fish,  to  be  boiled  for  four  or  five 
hours;  after  which  they  are  suffered  to 
cool  and  settle,  for  a  few  days  :  iu  cases 
where  these  substances  cannot  be  easily 
procured,  eight  quarts  of  water  may  be 
added  to  every  pound  of  barilla,  and  the 
mixture  allowed  to  dissolve  for  two  or 
three  days.  Next,  one  pint  of  pearl-ashes, 
or  of  purified  kelp,  or  wood  ashes,  must 
be  added  to  either  of  these  preparations; 
and,  after  the  whole  has  been  duly  mixed, 
for  24  hours,  a  certain  portion  of  lime 
is  slacked  in  the  compound,  for  the  pur- 
pose of  imparting  the  caloric  ;  of  preci- 
pitating the  carbon  of  the  ashes  ;  and  mo- 
derating the  causticity  of  the  liquor — 
Now  40  quarts  of  water  are  to  be  boiled 
with  one  quart  of  fish,  linseed  or  other 
oil;  adding  to  this  decoction,  half  an  ounce 
of  the  salt  of  sorrel,  or  of  sugar,  or  of  the 
rectified  salt  of  tartar;  the  object  of  which 
is  to  combine  the  oil  with  the  water. — 
Lastly,  after  this  composition  has  stood 
for  12  hours,  it  is  to  be  strained,  and  one 


quart  of  such  oily  water,  to  be  mixed 
with  every  twelve  quarts  of  the  liquid, 
prepared  in  the manner  above  described  : 
when  the  mixture  is  completely  settled, 
it  forms,  what  the  patentee  calls  a  blanch- 
ing lixivium. 

The  linen,  woollen, cotton  or  silk  stuffs, 
hats  or  leather,  are  to  be  immersed  in  lix- 
ivium, and  extended  on  a  frame.  Caout- 
chouc is  then  to  be  dissolved  in  spirit  of 
turpentine,  (the  smell  of  which  may  be 
dissipated,  by  the  addition  of  equal  parts 
of  oil  of  wormwood,  and  spirit  of  wine,) 
so  as  to  form  a  varnish  ;  this  liquor  must 
now  be  applied  to  the  wrong  side  of  the 
stuffs  that  are  to  be  prepared,  by  means 
of  a  solid  piece  of  India  rubber  ;  and  mi 
nute  shreds  of  cloth,  wool,  silk  or  worst- 
ed,  should  be  sifted  over  the  varnish  :  in 
the  course  of  two  or  three  days,  it  will  be 
perfectly  dry  ;  and  the  shreds,  by  their 
adhesion  to  the  dissolved  caoutchouc, 
will  form  a  lining  impermeable  to  wa- 
ter. 

In  1801,  another  patent  was  granted  to 
Messrs.  Ackermann,  Suardy  and  Co.  for 
the  invention  of  a  process,  by  which  every 
species  of  cloth  may  be  rendered  water- 
proof. As  the  patentees  have  not  thought 
proper  to  publish,  the  particulars  of  their 
process,  Dr.  Wiliich  observes,  that  wc 
shall  briefly  remark,  from  our  own  ob- 
servation, that  their  method  appears  to 
be  a  simple  impregnation  of  cloth,  with 
wax  previously  dissolved,  and  incorporat- 
ed with  water,  by  the  addition  of  pure 
vegetable  alkali  or  pot-ash.  This  being 
the  cheapest  and  most  expeditious  mode 
of  reducing  wax  to  a  fluid  state,  we  are 
farther  inclined  to  believe,  that  our  con- 
jecture is  well  founded;  because  all  the 
woollen  cloth,  prepared  in  the  manufac- 
tory of  Messrs.  Ackermann,  Suardy,  and 
Co.  reels  somewhat  harder  than  such  as 
has  not  been  waxed ;  for  the  same  reason, 
it  will  stand  a  shower  of  rain,  only  so 
long  as  it  has  not  been  subject  to  friction; 
and  we  understand  from  those,  who  have 
worn  patent  water-proof  coats,  that  in  the 
sleeves  particularly,  they  are  very  apt  to 
admit  moisture  through  the  different 
folds.  Nevertheless,  their  process  is  en- 
titled to  attention  ;  and  it  deserves  to  be 
adopted  principally  in  those  cases,  where 
the  manufacture  is  not  liable  to  be  im- 
paired by  friction  ;  such  as  coverings  for 
tents;  for  horses  exposed  to  the  rain  when 
at  rest ;  and  especially  for  paper  in  which 
gunpowder,  or  steel  and  other  goods,  are 
to  be  packed. 

Mr.  Bellamy's  invention  for  making  all 
kinds  of  leather  water-proof;  consists  of 
two  compositions,  which  are  prepared  in 
the  following  manner. 


WAT 


WAT 


First  Method. 
One  gallon  of  nut-oil,  and  an  equal 
quantity  of  poppy-oil,  are  to  be  mixed 
with  three  gallons  of  linseed-oil,  or  one 
gallon  of  nut,  or  poppy-oil,  may  be  add- 
ed to  three  of  that  expressed  from  lin- 
seed :  or,  two  gallons  of  the  latter  may 
be  combined  with  one  pint  of  nut,  and  a 
similar  quantity  of  poppy-oil.  These  in- 
gredients (in  the  proportions  above  men- 
tioned, or  such  as  the  nature  of  the  oil 
may  require,)  are  to  be  poured  together 
into  an  earthen  pot,  and  placed  over  a  gen- 
tle fire  :  to  each  gallon  of  oil,  must  be 
allowed  one  pound  of  white  copperas,  su- 
gar of  lead,  colcothar,  or  any  other  dry- 
ing substance.  The  whole  is  to  remain 
for  the  space  of  six  or  seven  hours  over 
such  a  degree  of  heat,  as  it  will  bear  with- 
out rising,  till  it  become  sufficiently  dry ; 
when  it  may  be  taken  off;  and,  as  soon  as 
it  is  cool,  the  compound  will  be  fit  for 
use. 

Second  Method. 

Gum  resin,  one  pound ;  pitch  half  a 
pound ;  tar  of  turpentine,  of  each  4  ounces, 
are  to  be  added  to  one  gallon  of  the  oils 
prepared,  according  to  the  first  method  : 
these  ingredients  are  to  be  well  mixed 
with  the  oils,  first  by  gently  heating  the 
whole  mass,  then  increasing  the  fire,  till 
the  whole  become  thoroughly  incorpo- 
rated. The  patent  specifies  various  pro- 
portions, in  which  the  ingredients  may  be 
used  ;  but  experience  will  be  the  best 
guide  to  ascertain  them. 

When  the  oils,  prepared  conformably 
to  the  first  method,  or  the  gums,  &.c.  ac- 
cording to  the  second,  are  sufficiently 
cool,  Mr.  Bellamy  directs  a  brush  to  be 
dipped  in  the  preparation,  which  should 
be  rubbed  into  the  leather.  As  soon  as 
that  article  is  thoroughly  impregnated,  it 
ought  to  be  laid  on  an  even  board  and 
the  superfluous  matter  removed  from  its 
surface  With  respect  to  sole  leather,  or 
similar  thick  substances,  he  observes, 
that  they  should  first  be  gently  warmed ; 
the  composition  is  then  to  be  applied  till 
they  are  fully  saturated  ;  and  after  being 
properly  dried  in  a  warm  place,  they  will 
be  ready  for  use 

In  the  Memoirs  of  the  Academy  of  Sci- 
ences of  Turin,  for  1789,  we  meet  with  an 
interesting  communication  by  M.  de  St. 
Ileal ;  on  the  means  of  rendering  leather 
(especially  that  destined  for  soles,)  im- 
permeable to  water,  without  diminishing 
its  strength.  This  object,  he  conceives, 
may  be  effected,  without  any  alteration  in 
the  usual  method  of  tanning,  by  the  com- 
mon operations  of  currying ;  provided  the 
skins  be  compressed  in  certain  heavy  roll- 


ers, after  being  previously  immersed  in 
beef-fat,  or  oil.  The  additional  greasing, 
and  pressing,  will  not  greatly  increase  the 
price  of  sole  leather  ;  which,  after  being 
a  whole  year  in  tanning,  imbibes  water  in 
a  much  smaller  proportion  than  cow- 
leather,  when  dressed  with  fat.  We  re- 
gret that  our  limits  do  not  permit  us  to 
specify  the  very  ingenious  experiments, 
made  by  M.  de  St.  Real ;  as  we  are  con- 
vinced, they  will  contribute  to  improve 
the  art  of  tanning. 

Another  method  of  preventing  leather 
from  being  penetrated  by  water,  consist* 
in  exposing  it  with  the  fiesh-sid£"  towards 
the  fire  :  after  which,  a  coat  of  warmed 
tar  is  to  be  applied  with  a  proper  brush, 
three  or  four  times  successively,  accord- 
ing to  the  thickness  of  the  leather,  till  the 
liquid  matter  penetrate  through  the  whole 
skin.  The  durability  and  strength  of 
shoes,  Sic.  will  be  considerably  increased, 
if,  in  laying  on  the  last  coat  of  tar,  they 
be  sprinkled  over  with  a  small  quantity 
of  fine  iron-filings,  which  will,  in  a  man- 
ner, fill  up  the  pores  of  the  leather.  Last- 
ly, shoes  may  be  rendered  impermeable 
to  moisture,  by  occasionally  rubbing  the 
soles  with  hot  tar :  thus  the  feet  may  be 
preserved  dry  and  warm  :  an  important: 
object  in  this  climate,  especially  during 
the  winter  season. 

The  fishermen  of  New-England  pre- 
serve their  boots  water-proof,  by  the  fol- 
lowing composition  :  One  pint  of  boiled 
lint-seed  oil,  half  a  pound  of  mutton  suet, 
six  ouuees  of  pure  bees-wax,  and  four 
ounces  of  rosin.  These  ingredients  are 
melted  together  over  a  slew  fire,  and  the 
boots  or  shoes,  when  new  and  quite  clean, 
are  warmed,  and  rubbed  with  the  compo- 
sition, till  the  leather  is  completely  satu- 
rated. 

There  is  an  improved  composition  for 
preserving  leather,  the  good  effects  of 
which,  are  sufficiently  ascertained.  One 
pint  of  drying  oil,  two  ounces  of  yellow 
wax,  two  ounces  of  spirit  of  turpentine., 
and  half  an  ounce  of  Burgundy  pitch, 
should  be  carefully  melted  together  over 
a  slow  fire.  With  this  mixture  new  shoes 
and  boots  are  rubbed  either  in  the  sun,  or 
at  some  distance  from  a  fire,  with  a  sponge 
or  brush  :  the  operation  is  to  be  repeated 
as  often  as  they  become  dry,  until  they 
be  fully  saturated.  In  this  manner,  the 
leather  becomes  impervious  to  wet,;  the 
shoes  or  boots  made  of  it,  last  much  Ion- 
ger  than  those  made  of  common  leather  ; 
acquire  such  softness  and  pliability  that 
they  never  shrivel,  nor  grow  hard  and  in- 
flexible ;  and,  in  that  stale,  are  the  most 
effectual  preservatives,  against  cold  and 
chilblains.    It  is,  however,  necessary  to 


WAX 


WAX 


remark,  that  shoes  or  boots,  thus  prepar- 
ed, ought  not  to  be  worn,  till  they  have 
become  perfectly  dry,  and  elastic  ;  as,  in 
the  contrary  case,  the  leather  will  be  too 
soft,  and  wear  out  much  sooner  than  even 
the  common  kind. 

In  "  An  Essay  on  Shooting,*''  the  follow- 
ing  composition  is  given. 

Tallow,  half  a  pound. 

Hog's  lard,  4  oz. 

Turpentine,  ~) 

New  bees  wax,  C  2  oz.  each. 

Olive  oil,  3 

To  be  melted  by  a  gentle  heat,  and 
rubbed  on  the  leather  (when  free  from 
dampness,)  the  night  before  the  shoes  or 
boots  are  wanted. 

Mr.  Johnson,  of  New-Brunswick,  has 
given  the  following  receipt. 

Take  five  parts  tallow,  seven  ditto  bees- 
wax, twelve  ditto  size,  one  ditto  brown 
soap,  four  ditto  lamp-black  ;  incorporate 
the  whole  over  a  fire,  (adding  the  ingre- 
dients one  by  one,  and  stirring  the  mass 
well,)  then  make  it  into  cakes. 

The  size  is  either  glue  dissolved  in  wa- 
ter to  a  jelly,  or  else  strong  jelly  made  of 
gum  tragacanth  in  water  ;  or  a  jelly  made 
by  boiling  glue  pieces  (bought  of  tanners) 
in  water,  to  a  proper  consistency,  and 
strained. 

Blacking  made  agreeably  to  the  fore- 
going receipt,  feeds  the  leather,  and  when 
brushed  bright,  gives  it  the  colour  and 
appearance  of  new  leather.  It  is  also  best 
adapted  for  cleaning  ladies'  Morocco 
shoes  :  and,  if  it  be  required  to  make 
it  more  shining,  more  size  may  be  add- 
ed. 

Several  receipts,  for  the  same  purpose, 
may  be  found  in  the  Sporting  Magazine, 
and  in  Tilloch's  Magazine. 

WAX.  There  are  two  or  three  sub- 
stances which  resemble  each  other  so 
closely,  as  to  have  received  the  name  of 
wax.  The  first,  and  by  far  the  most  im- 
portant, is  Bees  Wax,  which  is  consumed 
in  such  vast  quantities  for  giving  light, 
and  is  also  used  for  a  variety  of  other 
purposes.  Another  kind  of  wax  is  the 
myrtle  wax,  which  is  extracted  pretty 
largely  in  Louisiana,  and  some  othe  parts 
of  our  country,  from  the  Myrica  Ccrifera. 
Another  substance  very  similar  to  wax  is 
the  Pe  La,  of  the  Chinese,  the  product 
of  an  insect,  the  exact  species  of  which 
is  not  known  ;  and  the  white  matter  which 
Yields  the  Laccic  acid,  has  also  a  strong 
resemblance  to  wax. 

The  properties  which  all  these  sub- 
stances have  in  common,  are  fusibility  at 
a  moderate  heat ;  when  kindled,  burning 
with  much  flame  ;  insolubility  in  water, 
solubility  in  alkalies,  and  also  in  alcohol 


and  ether.  In  these  two  latter  properties 
all  the  species  of  wax  differ  from  the 
concrete  oils,  with  which  in  other  res- 
pects they  have  a  very  strong  resem- 
blance. 

Bees  Wax  is  the  substance,  excreted 
from  the  body  of  the  bee,  of  which  these 
insects  construct  their  cells,  both  those 
for  containing  honey  and  for  the  lodge- 
ment of  their  young.  It  is  collected  for 
the  use  of  man  wherever  bees  are  kept. 
A  young  hive  will  yield  at  the  end  of  the 
season  about  a  pound  of  wax  ;  and  an  old 
hive  about  twice  as  much.  The  colour 
of  wax,  when  fresh  from  the  bee,  is  near- 
ly white,  but  it  soon  grows  considerably 
yellow  in  the  hive,  or  if  very  old  is  of  a 
dark  brown.  The  origin  of  the  wax  we 
shall  mention  afterwards.  The  finest  wax 
is  found  to  be  made  in  dry,  healthy,  or 
hilly  countries,  but  it  is  decidedly  inferi- 
or, in  parts  fall  of  vineyards.  The  loaves 
of  common  bees  wax  are  made  immedi- 
ately from  the  common  honey-comb,  by 
a  slight  preparation.  The  combs  are  first 
emptied  of  all  the  honey  that  can  be  col- 
lected by  the  press,  and  are  then  either 
soaked  for  some  days  in  clear  water,  to 
extract  all  the  remaining  honey,  or  in 
some  parts  they  are  broken  down  and 
spread  on  a  sheet  in  the  neighbourhood 
of  the  hives,  and  in  time  the  bees  suck 
out  all  the  honey  that  is  left,  and  reduce 
the  wax  to  small  pieces  like  bran.  The 
whole  of  the  wax  is  then  melted  in  a 
clean  copper,  with  boiling  water,  and 
strained  by  a  press  through  cloth  bags,  to 
free  it  from  every  impurity.  It  is  then 
cast  into  cakes,  in  which  form  it  is  re- 
ceived by  the  wax-refiners. 

The  wax  of  these  cakes,  which  is  the 
ordinary  bees  wax  of  the  shops,  is  a  pale 
yellow  substance,  of  an  agreeable  honey- 
like smell,  soft,  and  somewhat  unctuous 
to  the  touch,  but  without  sticking  to  the 
fingers,  in  winter  becoming  considerably 
hard  and  tough,  and  meiting  at  about 
142°. 

This  yellow  colour  and  the  smell  of 
wax  are  entirely  taken  away  by  exposing 
it,  when  divided  into  thin  laminae,  to  the 
united  action  of  the  light  and  air,  and  by 
this  means  it  becomes  perfectly  white, 
scentless,  somewhat  harder  and  less 
greasy  to  the  touch,  and  in  this  state  it  is 
employed  for  candles  and  many  other 
purposes.  The  process  of  bleaching  wax 
is  the  following :  The  yellow  wax  is  first 
broken  into  small  pieces  and  melted  in  a 
copper  cauldron,  along  with  a  very  little 
water,  just  sufficient  to  prevent  the  wax 
from  burning,  for  it  is  of  importance  to 
use  no  more  heat  than  is  necessary.  The 
plug  of  the  copper  is  then  drawn,  and 


WAX 


WAX 


the  melted  wax  and  water  fall  together 
into  a  vessel  below,  where  it  is  covered 
with  a  thick  cloth,  to  keep  in  the  heat 
for  some  time,  that  the  water  and  impu- 
rities may  settle.  The  clear  melted  wax 
is  then  suffered  to  flow  into  a  vessel  with 
tiie  bottom  full  of  small  holes,  about  the 
size  of  a  grain  of  wheat,  whence  it  falls 
in  small  streams  upon  a  cylinder  kept 
constantly  revolving  over  water,  in  which 
it  partly  dips,  by  which  the  wax  is  im- 
mediately cooled,  and  at  the  same  time 
drawn  out  into  ttnn  shreds  or  ribbands. 
These  shreds  are  then  spread  upon 
cloths  stretched  on  large  frames,  which 
are  supported  a  foot  or  two  from  the 
ground,  and  after  exposure  to  the  sun 
and  air  tor  several  days,  with  frequent 
turning,  their  yellow  colour  nearly  disap- 
pears. The  half-bleached  wax  is  then 
heaped  up  in  a  solid  mass,  and  allowed 
to  remain  lor  a  month  or  six  weeks,  alter 
which,  to  give  it  complete  whiteness,  it 
is  re-melted,  and  ribbanded,  and  bieach- 
ed  as  before,  till  it  is  entirely  void  of  co- 
lour and  smell.  Some  manufactures  add 
in  the  re-melting,  either  alum  or  cream 
of  tartar,  or  sometimes  milk,  all  ol 
which  are  supposed  to  increase  the  white- 
ness and  solidity  of  the  wax. 

Instead  of  spreading  the  ribbands  of 
wax  on  cloths,  some  employ  a  broad 
course  of  bricks  laid  evenly,  which  are 
frequently  watered  to  prevent  the  wax 
from  melting  by  the  heat  of  the  sun  ab- 
sorbed by  the  bricks. 

Although  the  bleaching  of  wax  is  gene- 
rally, if  not  always,  performed  in  the  air, 
by  the  assistance  of  the  sun  and  moisture, 
vet  the  operation  may  be  considerably  fa- 
cilitated by  means  of  oxymuriatic  acid, 
or  the  saline  combinations  formed  with 
this  acid.  For  this  purpose,  the  acid  is 
prepared  as  formerly  directed  in  the  ar- 
ticle on  bleaching,  and  in  the  appendix  to 
Vol.  1.  and  the  wax  after  having  been  re- 
duced in  the  manner  before  stated,  may  be 
put  into  it,  or  in  the  solution  of  the  oxy,  or 
hyperoxy  muriatic  acid,  and  in  a  few  hours 
will  be  completely  bleached.  The  ex- 
pense of  bleaching  required,  is  not  so 
considerable ;  and  we  think  it  economi- 
cal, Vhen  it  is  considered  that  the  pro- 
cess may  be  performed  at  all  seasons  of 
the  year,  and  the  facility  with  which  the 
operation  is  finished. 

Wax  is  frequently  adulterated  by  tal- 
low, suet,  or  animal  fat  of  some  kind  or 
other.  This  gives  the  mixture  a  great  fu- 
sibility, so  that  when  ribbanded  and  ex- 
posed to  a  hot  sun,  it  is  extremely  apt  to 
cake.  It  also  takes  away  from  it  the  se- 
mi-transparency, which  is  a  distinguish- 
ing property  of  pure  bleached  wax ;  for 


though  fine  tallow  la  full  as  white  as  wax, 
it  is  always  a  dead  opake  white-  The 
adulteration  may  also  be  detected  by 
boiling  alcohol,  which  dissolves  wax  but 
not  tallow. 

Bleached  wax  burns  with  a  very  pure 
white  light,  and  gives  no  offensive  smell, 
and  very  little  smoke  compared  with  tal- 
low. Being  less  sensible  than  tallow,  it 
requires  a  smaller  wick.  Bleached  wax 
melts  at  about  lo5y  or  7°  higher  than 
the  unbleached.  Its  specific  gravity  is 
less  than  that  of  water,  being  about  .96. 

Alcohol  has  no  sensible  action  on  wax 
when  cold,  but  on  boiling  this  fluid,  it 
dissolves  rather  less  than  one -twentieth 
of  its  weight  of  wax. 

Sulphuric  ether  dissolves  wax  when  a 
little  heated. 

When  wax  is  boiled  in  caustic  potash, 
the  fluid  becomes  turbid,  but  after  a  time 
most  of  the  wax  rises  to  the  surface,  and 
in  a  flocculent  form. 

Pure  ammonia  acts  nearly  as  the  fixed 
alkalies. 

If  wax  is  distilled  with  a  greater  heat 
than  that  of  boiling  water,  it  is  decom- 
posed. 

As  the  distillation  advances  the  acid 
becomes  stronger,  and  the  oil  much  more 
copious  and  thicker,  till  at  last  its  con- 
sistence is  such  as  to  become  solid  in  the 
receiver,  when  it  is  called  Butter  of 
Wax. 

The  essential  oils  dissolve  wax  but 
sparingly. 

The  action  of  the  acids  upon  yellow 
wax,  has  been  examined  in  a  series  of  ex- 
periments by  Beckman,  particularly  with 
a  view  to  their  bleaching  power.  The 
6ame  subject  has  also  been  followed  by 
Sennebier,  who  has  added  some  remarks 
on  the  effect  of  light  and  other  supposed 
decolouring  agents. 

The  operation  of  light  was  thus  shewn  : 
some  yellow  wax  was  melted  and  thinly 
spread  on  a  plate  of  glass;  a  similia: 
plate  was  laid  upon  it  when  hot,  and  the 
edges  of  the  plates  were  closed  with  seal- 
ing wax.  The  bees  wax  therefore  was 
deprived  rof  the  access  of  air,  and  it  was 
placed  in  the  sun,  and  exposed  to  its  light 
for  four  or  five  days  daily.  Another  quan- 
tity of  wax  was  inclosed  between  plates  in 
a  similar  manner,  but  kept  in  the  dark. 
In  two  days  the  wax  kept  in  the  sun,  be- 
gan to  bleach,  and  in  a  month's  time  the 
whole,  where  it  did  not  exceed  two  lines 
(one  sixth  of  an  inch)  in  thickness,  was 
quite  white,  whilst  no  change  whaterer 
took  place  in  that  which  was  kept  in  dark- 
ness. 

If  thin  shavings  of  wax  are  immersed 
in  either  of  the  three  mineral  acids,  a  lit- 


WAX 


WEA 


tie  dilute,  in  a  few  hours  the  yellow  co- 
lour disappears;  and  the  wax  is  rendered 
partly  white,  partly  pellucid.  No  fur- 
ther  change  takes  place,  nor  is  the  co- 
lour of  the  acid  at  all  altered  (unless  heat 
he  applied)  for  many  weeks.  The  bits  of 
wax  are,  however,  much  hardened  by  re- 
maining in  the  acid,  so  as  to  rattle  when 
shaken  against  the  sides  of  the  glass,  and 
by  a  brisk  agitation  they  may  be  broken 
down  into  very  minute  white  flocculi. 
This  change  takes  place  much  the  most 
rapidly  in  the  nitric  acid,  or  in  the  nitro- 
muriatic,  and  it  is  completely  effected  in 
an  hour  or  two.  It  also  happens  when 
wax  is  melted  in  nitric  acid,  though  less 
rapidly.  This  circumstance  led  the  au- 
thor of  these  experiments  to  hope  that 
something  might  be  done  in  the  large 
way  in  bleaching  wax  by  nitric  acid,  but 
this  hope  proved  fallacious,  for  on  remov- 
ing the  wax  from  the  acid,  and  melting  it 
in  water,  (which  is  necessary  to  extract 
the  acid)  the  wax  resumes  a  yellow  co- 
lour, and  the  water  also  becomes  of  a  high 
brown  yellow.  By  repeatedly  melting  the 
wax  in  water  (without  any  additional  acid) 
;t  becomes  more  and  more  yellow,  and  at 
the  same  time  grows  harder,  and  much 
more  fusible  than  at  first. 

Neither  is  the  vapour  of  burning  sul- 
phur, which  so  speedily  bleaches  silk  and 
many  other  substances,  more  successful 
in  depriving  wax  of  its  colour. 

Professor  Beckman  then  tried  the 
whitening  effect  of  fuller's  earth,  or  some 
similar  substance,  being  led  to  use  it 
irom  the  known  power  which  it  has  in 
whitening  and  purifying  tartar.  Some 
yellow  wax  was  melted,  and  a  quantity  of 
this  earth  finely  powdered,  was  sprinkled 
;n.  The  wax  "was  then  melted  out,  and 
being  fused  in  water,  it  appeared  grey, 
like  wax  half  bleached  in  the  common 
way,  which  the  author  supposes  would 
save  much  time  in  the  whole  process. 

A  few  words  may  be  added  as  to  the 
origin  of  wax.  It  is  usually  supposed 
that  the  wax  is  the  pollen  of  howers, 
which  the  bees  visibly  collect  on  their 
thighs,  and  afterwards  elaborate  in  some 
unknown  way.  The  great  difference  be- 
tween wax  and  this  matter,  which  the 
bees  collect,  has  however  been  long  re- 
marked. When  examined  by  the  micro- 
scope, this  little  mass  of  pollen  is  obvi- 
ously composed  of  a  number  of  hard 
-rains  compressed  together,  and  if  it  is 
i aid  on  a  hot  plate,  it  does  not  melt  as 
wax  would  do,  but  smokes,  dries  and  is 
reduced  to  a  coal,  and  if  kindled  it  burns 
without  melting. 

Some  late  very  curious  experiments  of 
Huber,  one  of  the  most  celebrated  apia- 


rists in  Europe,  has  further  shewn  that 
the  pollen  has  no  share  whatever  in  the 
formation  of  wax,  but  that  this  latter  sub. 
stance  is  produced  indiscriminately  fiom 
honey,  sugar  or  any  other  saccharine 
matter  which  serves  as  food  for  the 
bees. 

The  Myrtle  Wax  is  a  concrete  sub- 
stance, moderately  hard,  nearly  of  the 
consistence  of  bees  wax,  and  of  a  dingy 
green  colour.  It  is  contained  in  abun- 
dance in  the  berries  of  the  Myrica  latifo- 
lia,  a  fragrant  bushy  shrub,  with  leaves  - 
like  the  myrtle,  which  grows  abundantly 
in  many  parts  of  North  America ;  it  is  al- 
so procured  from  another  species  of  the 
same  genus,  the  Myrica  Gale,  which  is 
common  in  boggy  mosses  in  several  coun- 
ties of  England. 

A  very  large  quantity  of  the  myrtle 
wax  is  extracted  from  this  shrub  in  Lou- 
isiana, by  collecting  the  berries,  boiling 
them  with  water,  and  bruising  them  at 
the  same  time,  by  which  the  wax  melts 
out  and  rises  to  the  top,  as  a  thick  oily 
scum,  which  is  easily  separated.  The 
berries  yield  about  a  fourth  of  their 
weight  of  this  wax.  They  contain  also, 
according  to  M.  Cadet,  a  considerable 
quantity  of  gallic  acid. 

This  wax  has  been  examined  chemical- 
ly both  by  the  above-mentioned  chemist 
and  Dr.  Bostock,  and  it  is  found  to  re- 
semble bees  wax  so  closely,  in  the  most 
important  properties,  that  they  may  be 
classed  under  the  same  genus  of  chemi- 
cal bodies. 

No  attempts  have  yet  been  made  to 
bleach  it  in  the  large  way,  by  exposure 
to  the  sun  and  air. 

The  myrtle  wax  is  used  largely  in 
some  parts  of  the  United  States,  as  a 
material  for  candles,  and  on  the  whole  it 
appears  worthy  of  further,  attention. 

WftATHS  R-GLAS.S,    or  barometer. 
See  Meteorology. 

WEA  VING.  The  art  of  plain  weaving 
is  so  well  understood  in  every  pare  oi  the 
country,  that  we  presume  it  quite  unne- 
cessary to  enter  into  the  detail  of  a  pro- 
cess, which  is  known  to  almost  every 
house-keeper.  We  shall  therefore,  on 
this  part  of  the  subject,  content  ourselves 
with  some  general  observations,  which 
we  have  taken  from  a  work  of  standard 
merit.  In  describing  the  faults  to  which 
cloths  are  subject,  in  consequence  of  bad 
weaving,  our  author  says  : 

"  When  from  any  cause  the  weft  is  not 
regularly  interwoven  with  the  warp,  a 
deficiency  must  happen  in  the  cloth,  j 
which  is  called  by  the  weavers  a  scobb. 
This  may  proceed  from  several  causes  : 
the  most  frequent,  is  some  obstruction  ia 


WE  A 


WE  A 


the  warp,  which  prevents  any  portion  of 
it  from  rising  or  sinking-  regularly  when 
the  shed  is  formed;  of  course  the  shuttle, 
instead  of  passing  fairly  between  the 
t  hreads  of  the  warp,  passes  either  over  or 
under  the  portion  which  is  obstructed, 
and  the  weft,  at  that  place,  is  not  at  all 
interwoven  with  the  warp.  A  knot  or 
lump  upon  the  warp,  if  not  picked  away 
in  the  dressing,  will  often  obst  ruct  two  or 
three  threads,  and  form  a  small  scobb. 
When  the  weaver,  from  inattention,  con- 
tinues to  weave,  after  a  thread  of  warp 
has  been  broken,  it  very  frequently  cross- 
es between  a  number  of  the  threads  near- 
est to  it,  and,  by  obstructing  the  shed  in 
that  place,  will  cause  a  large  scobb. 
Scobbs  are  also  sometimes  produced  by 
the  lay  being  too  low  hung,  but  this  is 
more  frequent  in  weaving  with  the  hand 
shuttle  than  with  the  fly.  In  this  case, 
the  scobbs  are  always  near  the  list  or  sel- 
vage of  the  cloth. 

A  second  fault  in  cloth  is  known,  among 
weavers,  by  the  name  of  ujisp.  This  is 
most  frequent  in  light  fabrics,  and  is  oc- 
casioned by  any  particular  thread  or  weft 
not  being  struck  up  so  close  as  the  rest. 
Jisps  are  very  frequently  occasioned  by 
defects,  either  in  the  construction  or 
mounting  of  the  loom.  If  either  the  yarn 
beam,  or  cloth  beam,  are  not  turned  very 
true,  jisping  will  be  unavoidable.  Or  if 
either  the  heddles,  or  the  lay,  be  not  hung 
parallel  to  the  beams,  the  same  defect 
will  ensue.  If  the  loom  is  correctly  made 
and  mounted,  the  fault  must  be  with  the 
weaver,  and  this  is  only  to  be  surmount- 
ed by  attention  and  practice. 

The  other  faults  in  cloth,  generally 
proceed  from  inattention  in  the  manage- 
ment of  the  warp  or  weft.  If  threads  are 
inaccurately  drawn  through  either  the 
heddles  or  the  reed,  the  defect  will  be  ap- 
parent in  the  cloth. 

There  is  nothing  which  adds  more  to 
the  beauty  of  cloth  of  every  description, 
and  about  which  good  weavers  are  more 
solicitous,  than  a  tight  uniform  selvage. 
In  order  to  produce  this,  the  warp  must 
be  dressed,  even  with  greater  care  than 
what  is  necessary  in  the  middle  of  the 
web.  The  tightness  of  the  weft  also,  con- 
tributes materially  to  the  beauty  of  the 
selvage.  It  is,  sometimes,  the  custom,  to 
warp  a  few  splitfuls  at  each  selvage,  with 
coarser  yarn  than  the  body  of  the  web. 
In  many  kinds  of  cloth,  however,  the 
common  practice  is,  to  draw  the  threads 
which  form  the  selvage,  double.  That  is, 
to  draw  two  threads  through  each  hed- 
dle. 

The  threads,  which  form  the  warp  of 
the  selvages,  being  coarser  than  the  rest, 
VOL.  II. 


and,  also,  being  more  drawn  towards  the 
middle  of  the  web,  by  the  weft,  the  splits 
of  the  reed,  through  which  they  pass,  are 
apt  to  be  worn  much  sooner  than  the 
others.  A  weaver  should  carefully  at- 
tend to  this,  for  it  the  reed  is  injured,  the 
work  cannot  be  good.  When  cane  reeds 
are  used,  and  when  the  webs  wrought  in 
them  are,  generally,  of  the  same  breadth, 
it  is  now  very  common  to  make  those 
splits,  through  which  the  warp  of  the  sel- 
vages passes,  of  brass. 

It  is  unnecessary  to  enumerate  fur- 
ther, the  defects  which  may  occur  in  the 
weaving  of  cloth,  for  no  instructions  can 
altogether  supply  the  want  of  that  skill, 
which  is  only  to  be  attained  by  practical 
experience. 

Tweeting. 

This  species  of  weaving,  which,  pro- 
bably, derives  its  name  from  the  French 
Word  tonaille,  a  hand  towel,  is,  almost  ex- 
clusively, confined  to  thick  fabrics  of 
cloth.  The  application  of  it  is  very  ex- 
tensive, and  it  is  much  used  in  the  manu- 
facturing of  cloth  from  each  kind  of  ma- 
terial. It  possesses  also  this  advantage, 
that,  besides  forming  a  species  of  ground, 
it  is  applicable  to  an  infinite  variety  of* 
ornamental  decoration.  To  the  investi- 
gation of  the  first  of  these  properties,  we 
will,  for  the  present,  confine  ourselves. 

In  analysing  the  fabric  of  plain  cloth, 
it  is  found  that  every  thread  of  the  warp 
and  the  woof,  cross  each  other,  and  are 
tacked  together  alternately.  This  is  not 
the  case  in  tweeting,  for  in  this  manufac- 
ture only  the  third,  fourth,  fifth,  sixth, 
&c.  threads  cross  each  other,  to  form  the 
texture.  Tweeled  cloths  have  been  fa- 
bricated of  many  different  descriptions. 
In  the  coarsest  kinds,  every  thread  is 
crossed  :  in  finer  fabrics,  they  cross  each 
other  at  intervals  of  4,  5, 6, 7,  or  8  threads ; 
and  in  some  very  fine  tweeled  silks,  the 
crossing  does  not  take  place  until  the 
16th  interval. 

Before  proceeding  further,  it  may  be 
proper  to  explain  what  is  known,  among 
weavers,  by  the  appellation  of  flushing. 
When  any  thread,  or  portion,  whether  of 
warp  or  woof,  is  not  regularly  interwoven 
with  the  fabric,  as  in  plain  weaving,  that 
thread,  or  portion  of  threads,  is  said  to 
be  flushed.  By  referring  to  Fig.  2. 
Plate  24.  this  will  be  better  illustrated 
than  by  any  description. 

In  Fig.  3.  is  a  specimen  of  plain  cloth, 
as  it  would  appear  when  viewed  through 
a  microscope,  the  intersections  of  the 
threads  are  evidently  alternate.  Fig.  2. 
may  be  considered  as  a  representation  of 
tweeled  cloth,  upon  the  same  principle 
4  A 


WEA 


WEA 


tiiat  Fig.  3.  represents  plain  cloth.  This 
figure  will  show,  that  the  same  thread  of 
woof  remains  flushed,  or  disengaged  from 
the  warp,  while  passing  over  three  threads 
and  is  tacked  down  hy  passing  under  the 
fourth.  Now  were  this  cloth  turned  up- 
side down,  the  same  appearance  would 
take  place  in  the  warp.  That  is  to  say, 
every  fourth  thread  of  warp  would  he  in- 
terwoven with  the  woof,  and  the  remain- 
ing three  threads  would  he  flushed.  An 
inspection  of  the  figure  will  also  evince, 
that  the  threads,  both  of  the  warp  and 
woof,  are  interwoven  in  regular  succes- 
sion, and  at  regular  intervals. 

To  produce  these  effects,  a  number 
of  leaves  of  heddles  is  required,  equal  to 
the  number  of  threads  contained  in  the 
interval  between  each  intersection,  inclu. 
sive.  Thus,  when  every  third  thread  is 
to  be  interwoven,  three  leaves  are  requi 
red  :  if  every  sixth  thread,  six  leaves  will 
be  necessary,  and  so  of  all  the  others. 
For  this  reason,  the  different  species  of 
tweels  are  distinguished  by  the  number 
of  leaves  which  are  requisite  in  weaving 
them  ;  as  a  four,  a  five,  or  a  six  Leafed 
tweel,  &c.  The  specimen  in  Fig.  2.  is  a 
four  leafed  tweel. 

Tweeling  is,  in  many  instances,  ap- 
plied to  the  weaving  of  cloths  which  re- 
quire a  great  portion  of  strength,  thick- 
ness, and  durability. 

For  instance,  in  the  linen  manufac- 
ture, every  description  of  bed  and  table 
linen,  is  generally  tweeled ;  sometimes 
with  ornaments,  and  sometimes  without 
them.  In  the  silk,  tweeling  is  very  com- 
mon. Sometimes  it  is  employed  for  the 
sake  of  strength,  but  more  frequently  for 
the  display  of  colour.  In  the  woolen, 
strength  is  the  general  object;  and  in 
the  cotton,  it  is  most  commonly  the 
same. 

It  may  be  necessary  in  this  place,  to 
inquire  shortly  into  the  causes  which  ren- 
der tweeled  cloths  stronger  than  plain, 
and  to  ascertain  the  difference. 

In  so  far  as  the  strength  of  tweeled 
cloths  depends  solely  on  the  mode  of 
weaving,  that  strength  will  be  rather  di- 
minished than  increased,  when  compared 
with  plain  cloth,  containing  an  equal 
quantity  of  similar  materials.  For,  in 
the  texture  of  plain  cloth,  every  thread  is 
constantly  interwoven  ;  whilst  in  that  of 
tweels,  they  are'  only  interwoven  at  inter- 
vals. Now,  in  the  latter  case,  the  threads 
can  derive  no  mutual  support  from  each 
other,  except  at  the  intervals  where  they 
are  interwoven  ;  and  that  part  of  them 
which  is  flushed,  must  depend  entirely  on 
the  strength  of  the  individual  threads  ; 
those  of  the  warp  being  flushed  upon 


one  side,  and  those  of  the  weft  upon  the 
other. 

The  following  inference  will  naturally 
ai'ise  from  this.  Let  two  webs  of  equal 
length,  equal  breadth,  and  equal  in  the 
quantity,  quality,  and  fineness  of  the  yarn, 
be  woven.  Let  the  first  be  plain,  and  the 
second  tweeled.  The  quantity,  quality, 
and  fineness  of  the  materials  being  equal, 
their  strength  ought  to  be  so  also  But, 
if  by  strength,  we  understand  that  quali- 
ty, which  opposes  the  most  effectual,  and 
most  continued  resistance  to  the  decay 
of  cloth,  from  common  wearing :  the 
tweeled  web  (if  equally  used)  would  be 
in  tatters,  long  before  the  plain  one  was 
materially  injured.  This  is  the  idea  com- 
monly, although  inaccurately,  attached  to 
the  word  strength,  when  applied  to  the 
fabric  of  cloth  ;  and,  indeed,  the  above 
remark  will  not  be  found  universally 
true,  for  the  durability  of  cloth,  exposed 
only  to  common  wearing,  depends  partly 
upon  its  strength,  and  partly  upon  its 
flexibility. 

It  is  not,  therefore,  in  the  effect  of 
the  mechanical  operation,  but  in  the  faci- 
lity of  combining  a  greater  quantity  of 
materials  in  the  same  dimensions,  which 
this  mode  of  weaving  affords,  that  we  are 
to  look  for  superior  strength  or  durabili- 
ty. This  may  be  easily  illustrated.  When 
the  shed  of  any  web  is  opened,  every 
thread,  either  above  or  below  the  thread 
of  woof,  which  has  been  driven  through 
the  web,  will  oppose  a  certain  resistance 
to  the  operation  of  the  lav  in  driving  the 
shot  home;  and  the  sum  of  all  thfse  re- 
sistances will  be  the  whole  resistance. 
Now,  in  plain  weaving,  every  thread  \s  in- 
terwoven, and  therefore  opposes  its  por- 
tion of  resistance  ;  whereas,  in  a  four  leaf, 
ed  tweel,  every  fourth  thread  only  is  in- 
terwoven, and,  of  course,  gives  resist- 
ance. The  ratio  of  resistance,  therefore, 
will  be  inversely  in  proportion  to  the  num- 
ber of  leaves  in  the  tweel,  compared  with 
unity. 

In  the  warp,  the  friction  in  the  reed 
will  be  diminished  in  the  same  propor- 
tion; for  each  thread,  instead  of  changing 
its  place  at  every  shot,  changes  only  once 
in  every  four  shots.  Consequently,  much 
more  warp  may  be  crowded  into  the 
same  space  without  injury,  than  could  be 
done  in  plain  weaving. 

From  the  above,  we  may  safely  de- 
duce, that  the  strength,  or  durability,  of 
a  tweeled  web  will  be  somewhat  less  than 
the  proportion  of  the  materials  which  it 
contains,  will  be  to  that  of  a  plain  web, 
supposing  each  to  be  of  equal  strength 
and  quality. 

But,  when  the  fabric  is  very  close, 


WE  A 


WEA 


tweeled  cloth  possesses  another  advan- 
tage over  plain,  in  point  of  durability. 
When  the  warp  of  plain  cloth  is  very 
much  crowded  in  the  reed,  and  the  weft 
driven  very  closely  home,  the  threads,  in 
order  to  cross  each  other  alternately, 
must  deviate  very  materially  from  their 
natural  form,  which  is  a  straight  line; 
whereas,  when  woven,  they  become  ser- 
pentine. This  renders  the  cloth  very  li- 
able to  be  easily  cut,  or  chafed,  especial- 
ly when  composed  of  hard,  and  compara- 
tively inflexible  materials.  This  defect 
is  chiefly  observable  in  stout  linens*  and 
arises  from  the  inelastic,  and  inflexible 
nature  of  the  fibres  of  the  flax.  But  when 
tweeled,  as  the  threads  only  cross  at  inter- 
vals, the  deviation  from  the  straight  line 
is  much  less,  and  the  flexibility  of  the 
cloth,  of  consequence  much  greater. 

Carpets  must  be  Wove  in  the  Draw 
Loom. 

I  shall  therefore,  before  proceeding,  en- 
deavour to  describe  and  illustrate  the 
principle  and  construction  of  this  exten- 
sive and  useful  machine,  and  to  trace  the 
differences  which  generally  subsist  be- 
tween those  which  are  used  for  double 
cloths  or  carpets,  and  those  employed  for 
the  manufacture  of  damasks,  which  are 
fancy  weels  of  the  most  extensive  range 
of  pattern.  Draw  looms,  are  used  for  spot 
weaving,  when  the  pattern  is  extensive  ; 
but  the  construction  of  these  differs  very 
little  from  the  others,  and  the  small  de- 
viations, shall  be  noticed  in  their  proper 
place.  I  preferred  postponing  the  de- 
scription of  the  damask  draw  loom,  until 
I  could  also  introduce  that  for  carpets  ; 
both  for  the  sake  of  tracing  the  analogy 
between  them,  and  to  aff  ord  further  opor- 
tunities,  of  extending  my  inquiries  and 
examinations,  respecting  these  machines, 
which  are,  by  much,  the  most  complicat- 
ed used,  by  weavers. 

It  would  be  difficult,  if  not  impossible, 
to  give  representations  of  the  full  mount- 
ing of  an  extensive  draw  loom,  for  the 
number  of  cords  are  so  immense,  and 
they  are  necessarily  placed  so  close  toge- 
ther to  save  room,  that  it  would  create 
unnecessary  confusion,  to  attempt  to  de- 
lineate the  whole.  I  have  lately  seen  a 
damask  draw  loom  at  Dunfermline,  where 
the  manufacture  is  carried  to  great  ex- 
tent and  perfection.  This  loom,  winch  I 
was  assured  was  not  the  most  extensive 
in  the  place,  contained  120  designs  of  10 
spaces  each,  and  consequently,  was  adapt- 
ed to  work  a  pattern,  as  extensive  as 
could  have  been  effected  by  1200  leaves', 
upon  the  plan  of  the  back  harness.  I 


have  therefore,  represented  specimens  of 
the  working  parts  upon  a  limited  plan,  for 
the  most  extensive  are  only  continua- 
tions of  the  most  limited,  in  the  same  re- 
gular succession. 

These  plans  will  be  found  in  Plate  21. 

The  use  of  the  draw  loom,  is  to  com- 
bine much  mounting  in  a  small  space  ; 
consequently  the  shafts,  and  every  other 
part  which  is  composed  of  wood,  are 
avoided,  and  the  moving  apparatus  con- 
sists entirely  of  cordage.  That  part  of 
the  apparatus  which  serves  as  a  sub- 
stitute for  the  heddles  of  other  looms, 
is  called  the  harness,  and  passes  through 
a  flat  board,  containing  a  number  of 
holes,  or  other  divisions.  In  Fig.  l.the 
edge  of  the  board  is  represented  at  C, 
and  the  harness  passing  through  it  at 
H.  The  figure  is  a  transverse  eleva- 
tion of  that  part,  which  is  peculiar  to  the 
draw  loom,  the  front  leaves,  which  are 
worked  by  treddles,  and  all  other  parts  in 
front,  being  taken  away,  for  the  purpose 
of  shewing  these  parts.  In  the  draw  loom, 
the  draught  of  the  warp  through  the 
mails  of  the  harness,  is  always  in  uniform 
succession,  as  in  tweeling ;  but  it  is  cus- 
tomary  to  draw  a  number  of  threads 
through  the  same  mail,  as  in  the  back 
harness  used  for  the  diaper.  Indeed,  the 
draw  loom  harness  is  merely  an  exten- 
sion of  the  former,  effecting  the  same  end 
by  different  means.  Fig.  2.  is  a  repre- 
sentation of  the  flat  side  of  the  board,  the 
edge  of  which  is  seen  in  Fig.  1.  to  show 
the  way  in  which  the  holes,  or  divisions, 
through  which  the  harness  passes,  are 
placed.  Near  the  centre  of  each  twine  of" 
the  harness,  is  the  copper  or  pewter  mail, 
which  serves  as  the  eye,  and  each  is  kept 
tight  by  a  small  weight,  (generally  of 
lead)  hung  to  the  bottom.  Now,  if  we 
are  to  suppose,  that  the  range  of  the  pat- 
tern is  100  spaces  of  the  design,  for  1000 
or  any  number,  is  only  an  extension  of 
the  same  principle,  then  the  1st,  101st, 
201st,  &c.  twines,  after  passing  through 
the  board,  are  to  be  knotted  together,  be- 
cause all  rise  at  once,  each  being  the  first 
of  a  new  design.  In  like  manner,  the  2d, 
102d,  &c.  are  knotted,  and  so  on  until  the 
whole  succession  of  100  is  completed  To 
each  of  these  a  cord  is  then  tied,  which 
after  passing  over  a  putty  in  the  box  A 
(containing  in  this  case  100  pullies,)  is 
fastened,  in  a  horizontal  direction,  to  a 
fixture  on  one  side  of  the  loom,  and  near- 
ly level  with  the  box  A.  The  horizontal 
part  of  these  cords  is  marked  B,  and 
this  part  of  the  mounting  is  called  the 
tail. 

To  each  cord  in  the  tail,  another  cord 
is  tied  at  a  convenient  distance  on  one 


WEA 


"WEA 


side  of  the  loom,  and  passes  perpendicu- 
larly towards  the  floor,  near  which  they 
are  all  made  fast  to  a  cross  piece  of  wood. 
These  cords  are  called  simples,  and  are 
distinguished  by  the  letter  D.  Another 
stout  cord  F,  is  then  stretched  from  the 
roof  to  the  floor,  parallel  to,  and  at  a  small 
distance  from  the  simples.  These  ope- 
rations being  performed,  the  whole  must 
be  made  uniformly  tight,  and  care  must 
be  taken  that  all  the  mails  are  level,  and 
of  a  proper  height.  The  warp  is  then  to 
be  drawn  through  the  mails,  and  front 
mounting;  successively,  as  before  men- 
tioned, and  the  remaining  parts  for  lift- 
ing the  harness  to  form  the  design,  are 
to  be  applied. 

If  the  connection  from  the  harness  to 
the  simples  is  traced,  it  will  be  evident 
that  when  any  simple  is  either  pulled 
down,  or  strongly  to  one  side,  it  will  raise 
all  the  twines  and  mails,  with  which  it  is 
connected  ;  and,  when  relieved,  they  will 
be  pulled  back  to  their  former  places,  by 
the  weights  which  are  fastened  to  each 
As  the  simples  are  very  numerous,  and 
close  to  each  other,  it  would  be  impossi- 
ble, in  a  heavy  design,  to  select  those 
which  should  be  successively  pulled, 
without  a  great  waste  of  time,  unless 
means  of  regular  and  speedy  selection  are 
employed.  This  is  effected  by  means  of 
another  set  of  cords  called  lashes,  repre- 
sented at  E,  and  connecting  the  simples 
with  the  cordF,  upon  both  of  which  the 
lashes  slide  easily  up  and  down.  The  ap- 
plication of  the  lashes  to  the  simples, 
must  be  regulated  by  the  pattern  to  be 
produced,  and  this  is  called 

Heading  on  the  Design. 
This  operation,  from  the  complexity  of 
the  patterns,  and  the  necessity  of  accura- 
cy, is  generally  performed  by  two  persons. 
The  pattern,  being  drawn  upon  design 
paper,  points  out  what  mails  are  to  be 
raised,  or  which  is  the  same,  what  sim- 
ples are  to  he  pulled  at  every  change  of 
the  harness.  It  is  the  business,  therefore, 
of  one  person  to  read,  or  rather  to  select, 
from  the  paper  what  simples  are  to  have 
lashes,  applied  to  them  at  every  change. 
The  other  person,  following  the  instruc- 
tions which  he  receives,  passes  a  lash 
round  every  simple,  which  is  pointed  out. 
He  then  knots  the  lashes  together,  and 
connects  the  other  end  with  the  cord  F, 
by  a  loop  round  it,  so  that  the  lashes  may 
slide  freely  upon  it.  The  other  end  pass- 
ing loosely  round  each  simple,  also  slides 
freely  upon  them.  The  lashes  must  be 
uniformly  tied,  that  the  simples  may  be 
pulled  equally.    A  single  instance  wiil  be 


sufficient  to  illustrate  how  the  design  is 

taken  from  the  design  paper. 

Let  Fig.  4.  Plate  24.  represent  the  de- 
sign of  a  flower,  any  number  of  which  are 
to  be  woven,  at  certain  intervals,  by  the 
draw  loom.  By  counting  the  spaces  upon 
the  design  paper,  it  will  uppear  that  this 
flower  covers  45  by  the  breadth,  and  35 
by  the  length.  The  former  gives  the 
number  of  mails  in  one  flower;  and  the 
latter,  the  number  of  changes  which  the 
harness  must  undergo  while  it  is  work- 
ing. When  the  warp  has  been  regularly 
drawn,  and  the  simples  applied,  the  lash- 
es are  to  be  placed  according  to  the  de- 
sign. In  this  case,  every  square  which  is 
black,  represents  a  simple  to  be  raised. 
Beginning  at  the  bottom,  it  appears  that 
only  two  mails  are  to  be  raised  for  the 
stem  of  the  flower,  and  counting  from  the 
right  hand,  these  will  be  raised  by  the 
3lst  and  32d  simple.  The  instruction, 
therefore,  given  to  the  person  who  ap- 
plies the  lash  is  ;  Pass  30  and  take  2.  On 
the  second  row  of  squares,  part  of  the 
flower  as  well  as  the  stem,  must  be  rais- 
ed, and  by  counting  as  before  from  the 
right,  passing  the  white,  and  taking  the 
black,  the  direction  will  be ;  Pass  18  take 
3  ;  pass  8  and  take  2.  On  the  third,  two 
other  parts  come  in  :  therefore,  pass  10, 
take  3  ;  pass  5,  take  5 ;  pass  7,  take  2  ; 
pass  7  and  take  4.  In  the  same  way,  the 
operations  are  continued,  until  the  whole 
35  are  completed,  always  passing  the 
white  and  taking  the  black. 

I  shall  add  the  whole  instructions  for 
this  flower,  by  comparing  which  with  the 
design,  the  principle  may  be  sufficiently 
understood,and  all  damask  patterns,  how- 
ever extensive,  are  done  exactly  on  the 
same  plan. 

1st,  Pass  30  and  take  2. 

2d,  Pass  18,  take  3  ;  pass  8  and  take 

2. 

3d,  Pass  10,  take  3  ;  pass  5,  take  5 ; 
pass  7,  take  2 ;  pass  7  and  take  4. 

4th,  Pass  9,  take  5  ;  pass  4,  take  5  ; 
pass  6,  take  3 :  pass  6  and  take  6. 

5th,  Pass  8,  take  7 ;  pass  3,  take  5 
pass  6,  take  4  ;  pass  4  and  take  7 

6th,  Pass  8,  take  7 ;  pass  4,  take  3  ;' 
pass  6,  take  2;  pass  2,  take  2  ;  pass  2  and 
take  8. 

7th,  Pass  8,  take  7  ;  pass  4,  take  2  ; 
pass  6,  take  3 ;  pass  2  and  take  11. 

8th,  Pass  9,  take  5 ;  pass  5,  take  2 ; 
pass  5,  take  4 ;  pass  2,  take  2  ;  pass  3  and 
take  4. 

9th,  Pass  10,  take  3 :  pass  8,  take  2  ; 
pass  2,  take  4  ;  pass  4  and  take  2. 

10th,  Pass  11,  take  2  ;  pass  10,  take  2; 
pass  2,  take  2 ;  pass  4  and  take  2. 


WE  A 


WE  A 


llth,  Pass  11,  take  2  ;  pass  10,  take  2  ; 
pass  2,  take  2  ;  pass  6  and  take  2. 

12th,  Pass  13,  take  3  ;  pass  3,  take  3  ; 
pass  4,  take  2  ;  pass  6  and  take  5. 

13th,  Pass  16,  take  4  ;  pass  5,  take  2 ;  j 
pass  8  and  take  8. 

14th,  Pass  25,  take  2;  pass  8  and  take  ; 


9. 


15th,  Pass  24,  take  2; 


;  pass  9,  take  3 

pass  8,  take  4. 
;  pass  7,  take  5 


9. 

16th,  Pass  8,  take  3  ; 
pass  11  and  take  8. 

17th,  Pass  7,  take  5 ;  pass  11,  take  2 
pass  14  and  take  6 

18th,  Pass  7,  take  6 
pass  16  and  take  3. 

19th,  Pass  7,  take  6; 

20th,  Pass  7,  take  6 
pass  7,  take  4. 

21st,  Pass  1,  take  3 ;  pass  4 
pass  6;  take  2 ;  pass  2,  take  3 ; 
take  6. 

22d,  Take  6,  pass  3  ;  take  4 
take  3,  pass  3,  take  14. 

23d,  Take  7,  pass  3 ;  take  2. 
take  2,  pass  3  ;  take  9. 

24th,  Take  8,  pass  2  ;  take  2,  pass  2 ; 
take  2,  pass  8 ;  take  2,  pass  3  ;  take  7. 

25th,  Pass  1,  take  13  ;  pass  10,  take  2  ; 
pass  5,  take  4. 

26th,  Pass  2,  take  5; 
pass  10,  take  2. 

27th,  Pass  10,  take  2; 
pass  7,  take  2. 

28th,  Pass  8,  take  4; 
pass  5,  take  2. 

29th,  Pass  7,  take  5; 
pass  5,  take  6. 

30th,  Pass  7,  take  5 
pass  5,  take  8. 

31st,  Pass  6,  take  6; 
pass  6,  take  8. 

32d,  Pass  6,  take  5; 
pass  6,  take  8. 

33d,  Pass  6,  take  5 ; 
pass  8,  take  7. 

34th,  Pass  6,  take  5  ; 

35th,  Pass  7,  take  3. 

From  this  it  will  appear,  that  the  shape 
of  every  pattern  wrought  in  the  draw 
loom,  depends  entirely  upon  the  mode  of 
connecting  the  lashes  and  the  simples. — 
Of  course,  the  pattern  may  be  altered  at 
pleasure,  to  any  other  which  does  not  ex- 
ceed the  range  of  the  mounting,  merely 
by  changing  the  order  of  this  connection. 
It  will  also  be  obvious,  that  in  ascertain- 
ing  the  order  from  the  design  paper,  the 
connection  of  the  lashes  with  the  simples, 
is  denoted  by  counting  from  right  to  left, 
or  vice  versa,  and  that  the  number  of 
changes,  and  consequently  the  number 
and  arrangement  of  sets  of  lashes,  on  the 
cord  F,  is,  in  like  manner,  ascertained  by 


counting  the  design,  from  the  bottom  to 
the  top.  The  first  set  is  generally  placed 
lowest  upon  the  cord,  and  the  rest  in  re- 
gular succession  above  it.    The  sets  are 
connected  with  each  other,  at  convenient 
distance,  by  pieces  of  twine  ;  so  that  by 
a  slight  pull,  they  will  follow  each  other 
:  in  regular  order.    When  the  connections 
pass  10  and  take  |  are  completed,  all  the  sets  are  pushed  up 
I  nearly  to  the  top  of  the  cord  F.  The 
pass  13,  take  2  j  loom  is  then  to  be  worked  by  two  per- 
|  sons,  one  of  whom  pulls  the  draught,  and 
j  the  other  manages  the  treddles,  shuttle, 
and  lay.    The  fore  mounting  is  exactly 
I  the  same,  in  every  respect,  as  the  diaper 
'  harness,  and  the  number  of  leaves  equal 
■  to  one  set  of  the  tweel.  For  the  ordinary 
i  qualities  of  damasks,  five  leaves  are  com- 
j  monly  used,  but  many  of  the  finest  are 
take  5  ;  |  wrought  with  eight. 

When  the  operators  are  ready  to  begin, 
i  the  person  who  draws,  pull  the  first  set 
!  of  lashes  down,  and  then  by  drawing  the 
simples,  and  consequently  the  tail,  raises 
!  that  part  of  the  harness,  attached  to  the 
!  part  which  is  pulled.    The  weaver  then 
;  works,  until  a  change  of  the  harness  be- 
|  comes  necessary.  The  person  who  draws, 
then  slacks  the  simples  which  had  been 
drawn,  pulls  down  the  second  set  of  lash- 
es and  draws  the  simples  as  before ;  the 
weaver  proceeds  to  work  until  another 
change  is  required,  and  so  on  until  the 
whole  pattern  is  completed.    In  the  de- 
sign given,  the  weaver  is  to  work  once 
over  his  treddles  between  every  change, 
and  this  is  generally  the  case  in  damask 
weaving. 

When  the  mounting  of  the  draw  loom 
is  very  extensive,  it  is  found  convenient 
to  have  two,  and  sometimes  three  boxes 
of  pullies  ;  for  were  the  whole  number 
of  pullies  placed  in  one  box  or  frame,  it 
must  be  extended  to  a  very  inconvenient 
size.  These  are  placed  parallel  to  each 
other,  as  represented  by  the  dotted  lines, 
in  Fig.  1.  PL  21.  and  an  equal  portion  of 
the  cordage  is  conducted  over  each,  ft 
is  also  common,  to  have  three  or  four  dif- 
ferent sets  of  simples,  and  lashes.  One 
set  of  these  is  stretched,  and  the  others 
are  loose  ;  and  each  set  is  stretched  in 
turn,  when  a  different  part  of  the  pattern 


pass  5 
pass  4 
pass  5 


pass  3,  take  4 ; 

;  pass  2,  take  4 
pass  2,  take  6 
pass  3,  take  6 

i  pass  3,  take  6 
pass  3,  take  6 
pass  5,  take  5 
pass  6,  take  3 
pass  19,  take  3 


is  to  be  wrought. 

"  Many  different  attempts  have  been 
made,  at  various  times,  and  with  various 
success,  to  supersede  the  necessity  of 
employing  an  additional  person  to  draw 
the  lashes,  by  constructing  the  appara- 
tus so,  that  the  weaver  may  draw  the 
harness,  as  well  as  work  the  treddles. 
The  most  recent,  and  probably  the  most 
generally  adopted  of  these  plans,  is  one 
which  has  been  lately  invented  and  in- 


WEA 


WEA 


troduced  at  Dunfermline,  where  it  is  now 
very  common.  It  is  known  there,  by  the 
name  of  the 

Patent  Draw  Loom . 
In  this  loom,  the  tail  of  the  harness, 
instead  of  being  carried  over  pullies  to 
one  side,  extends  perpendicularly  up- 
ward, and  is  fastened  to  the  roof  of  the 
shop.  Upon  each  cord  is  a  knot,  at  a 
convenient  distance  from  the  roof,  and  all 
the  knots  must  be  at  an  equal  heighth. 
The  simples  extend  horizontally  over  the 
Weaver's  head,  where  they  are  made  fast ; 
and  the  lashes  hang  down  from  these, 
and  have  generally  a  small  handle,  or 
bob,  as  it  is  frequently  called,  attached 
to  each.  An  instrument,  called  the  comb, 
from  its  figure,  is  hung  in  a  horizontal 
position,  and  moveable  on  its  centres.  The 


er,  and,  consequently,  require  less  cord 
age :  the  boxes  or  frames  of  pullies  are 
unnecessary,  and  the  space  occupied  by 
the  simples  at  the  side  of" the  loom  is  saved: 
and  3dly,  The  mechanical  apparatus  is  so 
applied,  that  much  less  power  is  required 
to  raise  the  harness,  which  must  be  of 
considerable  advantage  in  heavy  mounted 
looms,  where  the  strength  required  is  ve- 
ry considerable. 

By  reducing  the  way  in  which  the 
power  applied  in  both  cases,  to  the  ele- 
mentary principles,  the  difference  will  be 
found  to  he  very  great.  In  the  first  case, 
one  end  of  the  tail  is  made  fast,  and  the 
other  sustains  all  the  weights  attached  to 
the  harness  The  simples  which  are  pull- 
ed down  to  raise  the  harness  are  con- 
nected to  the  tail,  between  the  end  which 
^  is  fast  and  the  pullies.  Consequently,  the 
appearance  and  shape  of  the  comb  will  be  j  simples  act  in  the  same  ratio,  as  a  weight 
found  in  Fig.  4.  PI.  21.  which  represents  j  fixed  to  a  moving  pully,  suspended  by  a 
it  as  it  appears  when  viewed  from  above  rope  passing  through  the  pulley,  and  of 
or  below.  In  Fig.  5.  it  appears  as  view- !  which  rope  one  end  is  made  fast.  It  has 
ed  on  one  side.  In  both  these  figures  a  j  been  often  demonstrated,  that  a  weight, 
represents  the  centres,  b  the  teeth,  c  the  |  say  of  2  lbs.  in  this  situation,  will  be  ba- 
pull,  d  a  few  cords  representing  the  rela-  lanced  by  another  of  only  1  lb.  suspended 
tive  situation  of  the  tail  of  the  harness  to  !  from  the  other  end  of  the  rope,  after  pass- 
the  comb,  e  cords  representing  simples,  j  ing  over  a  fixed  pulley.  Hence  the  weight, 


and  f  Fig.  5.  the  situation  of  the  lashes. 
In  Fig.  5.  the  operation  is  represented  by 
two  cords  of  the  tail  d,  one  of  which  has 
the  knot  drawn  into  the  teeth  b,  and  the 
other  is  disengaged.  When  the  weaver 
pulls  down  any  particular  set  of  lashes, 
those  simples  to  which  they  are  attached, 
are  drawn  into  the  oblique  direction,  as 
ut  e,  and,  consequently,  pull  those  cords 
of  the  tail  to  which  they  are  tied,  between 
the  teeth  of  the  comb.  The  end  of  the 
lever  projecting  at  c,  being  then  pulled 
down,  and  secured  by  a  knot  in  a  notch, 
in  the  same  way  as  the  diaper  harness 
mounting,  the  teeth  rise,  and  by  means 
of  the  knots,  carry  up  that  part  of  the 
harness  which  is  drawn  betwixt  the 
teeth,  whilst  all  the  rest  remains  free. 
When  a  change  is  wanted,  the  comb  is  let 
down,  and  the  simples  being  slacked,  the 
cords  of  the  tail  quit  the  comb  ;  another 
set  is  drawn  in  by  pulling  another  set  of 
lashes,  the  comb  is  again  raised  and  se- 
cured as  before,  and  the  operation  pro- 
ceeds. The  weaver  pulls  the  lashes  with 
one  hand,  and  raises  the  comb  with  the 
other,  so  that  very  little  time  is  consumed 
in  changing  the  harness. 

The  patent  draw  loom  seems  to  pos- 
sess some  very  obvious  advantages,  which 
are  not  to  be  found  in  the  oid  loom.  It 
saves  the  labour  of  an  additional  person, 
and  the  operation  seems  to  be  conducted 
altogether,  or  nearly,  as  quick.  2diy, 
Both  the  tail  and  simples  are  much  short- 


or  the  power,  which  is  the  same  thing, 
applied  lo  the  simples  to  pull  them  down, 
must  be  somewhat  more  than  double  the 
sum  of  all  the  weights,  attached  to  that 
part  of  the  harness  which  is  to  be  raised. 
See  Mechanics. 

"But  in  the  case  of  the  patent  loom, 
the  harness  is  raised  perpendicularly  by 
the  comb  ;  consequently,  no  more  pow- 
er is  required  than  will  overcome  the  sum 
of  the  weights  to  be  raised;  and  if  the 
lever,  at  the  end  of  which  the  comb  is  fix- 
ed, be  divided  into  three  equal  parts,  and 
the  centres,  or  pivots,  placed  at  the  dis- 
tance of  one  of  these  parts  from  the  comb, 
the  power  will  be  again  doubled. 

From  these  calculations  we  may  de- 
duce, that  the  power  required  to  raise  the 
harness  of  the  patent  loom,  will  be  only 
about  one-fourth  of  that  required  for  the 
other. 

But  in  every  species  of  complicated 
mechanism,  many  deficiencies  and  objec- 
tions, which  may  not  be  obvious  to  the 
eye  of  a  transient  spectator,  frequently 
become  apparent  upon  practical  experi- 
ence. For  this  reason,  1  was  at  pains  to 
collect  from  these  who  were  daily  em- 
ployed in  working  them,  their  opinions  of 
the  comparative  merits  of  the  two 
plans. 

When  the  range  of  pattern  was  not 
very  great,  I  found  both  the  general  opi- 
nion and  practice,  which  is  still  more 
conclusive,  decidedly  in  favour  of  the  pa- 


WE  A 


"WEA 


tent  loom.  It  was  only  respecting  the 
very  highest  mounted  looms,  that  a  dif- 
ference of  opinion  seemed  to  exist.  I  was 
informed  that  two  looms,  of  very  exten- 
sive range,  had  been  lately  mounted ;  the 
first  of  120  designs,  upon  the  old  plan  ; 
the  second,  of  120  designs,  upon  the  pa- 
tent plan.  Both  looms  were  allowed  to 
execute  their  work  in  a  very  sufficient 
manner,  but  it  was  stated,  that  the 
mounting  of  the  patent  loom,  although 
last  set  to  work,  was  already  much  de- 
cayed, whilst  that  of  the  other,  which  had 
produced  more  cloth,  was  impaired  in  no 
perceptible  degree. 

Should  this  prove  to  be  generally  the 
case,  it  will  form  a  just  ground  of  hesita- 
tion, in  preferring  the  new  to  the  old  plan, 
in  looms  of  this  description.  The  mount- 
ing of  an  extensive  draw  loom,  is  a  w  ork 
necessarily  involving  much  time,  labour, 
and  expense,  and  the  loom  must  there- 
fore, be  employed  for  a  very  considerable 
portion  of  time,  before  it  will  indemnify 
the  proprietor.  But  it  may  be  possible, 
admitting  the  fact  to  be  as  stated,  which 
I  have  no  reason  to  doubt,  that  the  differ- 
ence of  the  mounting  of  these  two  looms, 
in  point  of  durability,  might  be  produced 
by  some  incidental  or  contingent  circum- 
stances in  their  construction,  independ- 
ent of  the  general  principle.  The  cord- 
age of  the  one  might  be  inferior  to  that 
of  the  other,  either  in  the  quality  of  the 
stuff,  in  the  spinning,  or  in  both.  Some 
part  of  the  machinery  might  have  been 
imperfect  in  the  workmanship,  and  caus- 
ed unnecessary  friction ;  the  mounting 
might  have  deviated  a  little  from  an 
equal  degree  of  tension,  or  from  the  true 
level,  which  must  produce  more  strain  on 
one  part  than  another.  Whether  any  of 
these  causes  did  operate  in  this  case,  I 
bad  no  means  of  ascertaining;  but,  in 
forming  opinions  respecting  complicated 
and  expensive  machines,  too  much  cau- 
tion cannot  be  used,  in  investigating,  not 
only  the  direct  principles  of  construction, 
but  all  the  minute  and  collateral  circum- 
stances which  may  affect  their  operations. 
Want  of  attention  to  this,  has  been  more 
injurious  to  the  improvement  and  exten- 
sion of  practical  mechanism,  than  any  cir- 
cumstance which  has  come  to  my  know- 
ledge upon  that  subject.  Therefore,  with- 
out offering  any  decided  opinion  upon 
the  fact  stated,  it  may  be  sufficient  to  re- 
mark, that  speculatively  and  abstractedly 
considered,  the  patent  loom,  particularly 
the  harness  part  of  it,  appears  to  possess 
some  advantage  over  the  other,  even  in 
point  of  durability.  The  tail,  instead  of 
being  conducted  over  pullies  to  one  side, 
rises  perpendicularly  to  the  roof;  consc. 


quently,  the  cords  deviate  much  less  f  rom 

a  straight  line,  and  the  decay  which  must 
be  produced,  both  by  the  friction  of  pul- 
lies, and  the  deflection  of  the  cords,  is, 
almost  entirely  avoided.  It  is,  however, 
to  be  allowed,  that  some  friction  will  be 
produced  by  pulling  the  cords  betwixt 
the  teeth  of  "the  comb,  and  afterwards,  by 
raising  the  harness,  and  that,  in  the  form* 
er  of  these  motions,  the  friction  is  almost 
at  right  angles  to  the  staple  of  the  hemp, 
or  lint,  which  is  a  very  unfavourable  di- 
rection. 

In  these  comparisons  of  the  old  and  pa- 
tent draw  looms,  I  have  endeavoured  im- 
partially., to  state  both  the  opinions  which 
1  had  collected,  and  the  remarks  Which 
occurred  to  myself  Probably,  some  time 
may  still  elapse,  before  the  superiority  of 
either  will  be  universally  admitted,  even 
by  those  who,  from  their  practic  al  expe- 
rience, have  the  best  opportunities  of 
forming  an  accurate  judgment  upon  the 
subject. 

But,  in  whatever  way  a  draw  loom  is 
mounted,  too  much  attention  cannot  be 
paid,  both  to  the  quality  of  the  materials 
and  accuracy  of  the  workmanship.  This, 
indeed,  is  a  general  rule,  and  will  be 
found  to  apply  to  every  description  of 
machinery.  No  plan  of  economy  can  be 
more  ruinous  in  its  effects,  than  that  of 
constructing  any  piece  of  mechanism  of 
insufficient  materials,  and  inaccurate 
workmanship,  for  the  sake  of  a  small  re- 
duction of  the  first  expense.  The  mount- 
ing of  an  extensive  draw  loom  will  occu- 
py a  man,  for  at  least  four  months.  Let 
us  then  suppose,  that  the  weaver  who 
works  this  loom,  besides  paying  the  per- 
son who  draws  the  harness,  if  he  em- 
ploys one,  can  earn  Is.  per  day,  more  than 
he  could  if  weaving  plain  cloth.  In  this 
case,  it  will  require  288  working  days  of 
constant  industry,  before  the  price  of  la- 
bour in  mounting  is  repaid,  exclusive  of 
the  whole  expense  of  the  materials.  It 
is  plain,  that  whether  a  weaver  mounts  a 
loom  for  himself,  or  employs  another  to 
do  it  for  him,  the  case  will  be  precisely 
the  same,  for  in  both  instances  the  price 
is  estimated  by  the  labour.  In  the  first 
instance,  labour  is  given  ;  in  the  second, 
money :  and,  by  the  supposition,  the  va- 
lue is  the  same.  But,  to  make  the  calcu- 
lation  simple,  let  us  suppose  that  an  ope- 
rative weaver  mounts  the  draw  loom 
which  he  is  afterwards  to  work.  By  the 
suppositions  which  we  have  made,  he 
will  expend  96  working  days,  in  the 
mounting,  before  he  begins  to  weave,  and 
288  working  days  in  weaving,  before  he 
recovers  common  wages  for  the  time 
which  he  has  expended.   These,  taken 


WE  A 


WE  A 


together,  amount  to  384  working1  days, 
to  which  adding  the  intervening  Sundays, 
(without  any  allowance  for  holidays, 
sickness,  or  other  causes  of  impediment,) 
he  will  at  the  end  of  one  year  and  83  days, 
or  nearly  15  months,  be  merely  paid  for 
his  labour.  Now  let  us  again  suppose 
that  the  money  expended  or  materials  of 
the  best  quality,  in  mounting  a  draw  loom, 
amounts  to  10*/.  and,  that  those  of  inferior 
quality,  might  be  purchased  for  6/.  Let 
us  suppose  also,  that  these  two  mountings 
will  last  in  proportion  to  their  prices, 
which,  in  practice,  is  never  the  case,  for 
the  vulgar  adage,  "the  best  is  always  the 
best  penny-worth,"  will  here  be  found  in- 
variably true.  In  this  case,  the  former 
will  last  ten  months  for  every  s  x  that  the 
latter  will.  Let  us  then  suppos  ,  that  the 
very  worst  mounting  will  last  for  two 
years,  and  the  best  for  three  years  and 
four  months  ;  the  calculation  will  then  be 


For  the  Worst. 
For  labour,  as  before  - 
For  materials 


L  14  8 
6  0 


20 


Return. 

Is  per  day  for  626  working  days    31  6 
The  profit  therefore,  to  the 

weaver,  will  be  10  18 

excluding  interest. 


For  labour 
For  materials 


For  the  Best. 


L.U  8 
10  0 


24  8 

Return. 

Is  per  day  for  1043  working  days  52  3 
Or  of  profit,  excluding  interest       28  15 

In  both  cases,  it  is  supposed,  that  each 
kind  of  material  has  been  laid  in  at  the 
fair  market  price,  and  that  no  impo- 
sition has  been  practised  on  the  buyer. 

The  grounds  upon  which  these  calcu- 
lations are  made,  have  been  taken  entire- 
ly at  random,  to  illustrate  and  prove  the 
position  advanced.  Whether  the  price 
of  wagesi  the  cost  of  materials,  or  the  du- 
rability of  the  apparatus,  be  taken  high 
or  low,  the  inference  will  be  nearly  the 
same.  In  every  state  of  the  price  of  la- 
bour, if  good  materials  1  only  repay  a 
weaver,  bad  will  ruin  him  ;  and,  if  bad 
materials  yield  him  a  profit,  good  ones 
would  yield  him  much  more.  Simple  as 
this  principle  is,  and  easily  demonstra- 
ble, there  are  few  from  which  there  are 
more  deviations  in  common  practice.  I 
have  known  incalculable  loss,  in  many 
instances,  arise  from  this  deviation,  and 
have,  therefore,  entered  more  into  the 


consideration  of  it,  than  I  should  have 
done,  were  it  more  generally  understood, 
and  practised  in  the  affairs  of  common 
life. 

We  now  proceed  to  consider  the  ap- 
plication of  the  draw  loom  to  the  weaving 
double  cloth,  and  explain  the  differ- 
ence which  exists  between  the  damask 
and 

Carpet  Draw  Loom. 

Carpets,  being  generally  composed  of 
coarse  and  bulky  materials,  there  are,  of 
course,  much  fewer  splits-  or  threads,  in 
the  warp,  than  in  that  of  a  damask  ;  and, 
consequently,  the  drawing  apparatus  is 
much  less  extensive.  The  common  run 
of  carpets  do  not  exceed  10  porters  of 
warp,  4  threads  in  the  split,  in  the  breadth 
of  37  inches,  which  is  equal  to  a  500, 
wrought  two  in  the  split  or  1000  threads 
The  harness  and  mails  of  the  carpet  draw 
loom,  are  perfectly  similar  to  those  of 
the  damask,  excepting  that  they  are 
larger  and  coarser.  In  drawing  a  carpet 
through  the  harness,  only  one  thread  pas  - 
ses through  each  mail,  and  one  thread  of 
each  of  the  two  warps  is  drawn  alternate- 
ly. The  draught,  through  the  harness, 
proceeds  in  regular  succession,  as  in  the 
damask,  and  two  threads  of  each  warp 
pass  between  the  same  splits  of  the  reed, 
which  is,  generally,  of  steel.  It  is  found 
in  general,  unnecessary  to  use  simples  in 
the  carpet  draw  loom  ;  the  lashes,  there- 
fore, are  attached  directly  to  the  cords  of 
the  tail,  from  which  they  hang  down  per- 
pendicularly at  one  side  of  the  loom.  To 
the  lower  end  of  each  set  of  lashes  is  tied 
a  cord,  and  to  the  other  end  of  this  cord, 
is  suspended  a  small  handle,  or  bob. 

Fig.  6.  Plate  21.  is  a  transverse  eleva- 
tion of  part  of  a  carpet  draw  loom,  show- 
ing how  the  lashes  and  bobs  are  attached 
to  the  tail.  A  is  the  box  or  frame  of  pul- 
lies,  B  the  tail,  C  the  lashes,  G  the  board 
through  which  the  cords  pass,  H  the  bobs. 
The  bobs  are  suspended  in  two  rows,  as 
represented  in  Fig  7.  which  is  a  section 
of  the  board  G,  showing  two  of  the  bobs. 
Of  these  bobs,  one  lifts  that  portion  of  the 
black  warp  which  is  to  be  uppermost ; 
the  other  lifts  the  white  in  the  same  man- 
ner, supposing  still  that  these  are  the  two 
colours  of  which  the  carpet  is  composed. 
The  four  front  leaves  open  the  sheds,  two 
being  set  apart  for  the  black  warp,  and 
two  for  the  white. 

The  front  leaves  of  the  carpet  draw 
loom  are  exactly  similar  to  those  of  the 
diaper,  the  eyes  being  of  a  length,  rather 
more  than  the  depth  of  the  shed,  so  that 
they  may  not  interrupt  the  harness  in  ris- 
ing. In  some  looms,  the  whole  is  mount- 
ed as  a  harness,  and  the  tfeddles  are  con- 


AVE  A 


WE  A 


nested  with  certain  of  the  tail  cords.  Up- 
on  inquiring"  of  persons,  who  had  been 
long  in  the  habit  of  working-  both,  I  could 
not  ascertain  that  any  decided  preference 
was  to  be  given  to  either  plan  Both  are 
found  to  do  very  well,  and  both  are  gene- 
rally used  in  different  manufactories. 

Let  us  now  suppose,  that  Fig.  4.  Plate 
24.  is  to  be  wrought  as  a  carpet,  and  that 
the  figure  is  black  upon  a  white  ground. 
In  this  case,  when  a  white  shot  is  thrown 
across,  the  figure  must  be  raised,  and  the 
ground  sunk  ;  and  when  a  black  shot  is 
inserted,  the  ground  is  to  be  raised,  and 
the  figure  sunk.  For  the  first,  the  instruc- 
tions, in  reading  on,  will  be  the  same  with 
those  given  for  damask,  and  for  the  se- 
cond, directly  the  reverse.  As  the  shots 
of  weft  are  thrown  in  alternately,  the  har- 
ness must  be  changed  at  every  shot,  and 
for  this  reason  the  bobs  are  placed  in 
pairs,  as  represented  by  Fig.  7-  Plate  21 
The  instructions,  therefore,  will  be 

1st.  White  shot,  pass  50  and  take  2. 
Black  shot,  take  30,  pass  2,  take  13. 

and  so  on,  whatever  is  passed  in  the  one 
case,  being  taken  in  the  other. 

Different  plans  have  been  tried  in  car- 
pet weaving,  as  well  as  damask,  to  su- 
persede the  use  of  the  draw  boy.  Hi- 
therto, none  of  them  have  come  into  ve- 
ry general  practice,  although  there  seems 
no  reason  to  doubt  that  some  saving  may 
be  effected  in  this  way.  Carpet  weaving, 
however,  does  not  possess  the  same  faci- 
lities for  this  as  damask,  for  in  the  form- 
er, as  the  harness  must  be  changed  at 
every  shot,  if  the  time  of  doing  so  should 
impede  the  weaver,  even  very  little,  more 
will  be  lost  than  an  equivalent  for  the 
wages  of  a  draw  boy.  Besides  this,  as 
the  weaver  must  shift  his  shuttle  at  every 
shot,  he  is  sufficiently  occupied  without 
being  obliged  to  change  his  harness. 

Carpets  are  seldom  warped  upon  mills, 
for  the  yarn  being  very  coarse,  the  wajp 
is  found"  not  to  be  sufficiently  stretched. 
A  square  frame  of  wood  is,  therefore, 
commonly  used,  with  pins  at  certain  dis- 
tances, over  which  the  warp  is  stretched 
by  the  warper,  in  a  manner  similar  to  the 
old  practice.  As  the  warps  of  carpets  do 
not  contain  many  threads,  this  practice 
is  considered  sufficiently  expeditious 

When  carpets  consist  of  more  than 
two  colours,  they  are  woven  exactly  as 
checks,  and  merely  require  additional 
shuttles  to  insert  the  weft,  the  same  as 
the  warp.  There  is  no  difference  in  the 
process  It  is  not  yet  customary  to  use 
the  fly  shuttle  in  carpet  weaving,  and 
when  the  webs  are  too  broad  for  one  man 
VOL.  II, 


to  stretch,  two  are  employed,  one  at  each 

side  of  the  loom. 

Many  kinds  of  carpeting  for  rugs,  pas- 
sage, and  stair  cloths,  fecare  also  woven 
in  the  plain  loom. 

Carpets  are  also  manufactured  with 
flushing  like  velvet,  which  is  afterwards 
cut.  When  this  is  the  case,  wires  are  in- 
troduced into  the  shed,  to  form  the 
length  of  the  flushing.  In  each  of  these 
wires  is  a  groove,  and  when  the  weft  has 
been  thrown  across,  a  sharp  pointed  knife 
is  passed  along  the  groove,  which  serves 
as  a  guide  for  it.  The  wire  is  thus  re- 
lieved, and  the  cut  warp  forms  the  flush- 
ing. These  may  be  either  wrought  plain, 
or  in  figures  raised  by  the  harness.  This 
manufacture  is  chiefly  carried  on  at  Kid- 
derminster, and  has  hardly  been  introdu- 
ced at  all  in  Scotland.  From  the  name, 
it  appears  to  have  been  originally  import- 
ed from  Turkey.  Very  elegant  carpets 
are  also  manufactured  in  France. 

Quiltings  are  also  double  cloths,  and 
are  manufactured  exactly  upon  the  same 
principle  as  carpets.  The  two  webs  are 
generally  of  the  same  colour.  This  man- 
ufacture is  also  derived  from  the  French, 
and  was  chiefly  carried  on  in  the  neigh- 
bourhood of  Marseilles.  Those  made  in 
England,  are  generally  of  cotton. 

Weaving  by  Mechanical  Power. 
I  now  come  to  consider  the  various 
plans,  which  have  been  lately  adopted  for 
the  purpose  of  working  the  weaving  loom, 
by  the  application  of  power.  Many  ex- 
periments, upon  a  small  scale,  have  been 
made  for  a  considerable  number  of  years 
past,  and  looms,  upon  various  plans,  con- 
structed. The  first  attempt  to  establish  a 
regular  manufactory  of  this  description, 
in  Scotland,  was,  I  believe,  that  of  Mr. 
Robert  Miller,  at  Milton  Printfield,  Dum- 
bartonshire, which  is  still  prosecuted. — 
These  looms,  for  which  a  patent  was  ob- 
tained, receivelheir  motion  from  treddles, 
moved  by  those  excentric  wheels,  which 
are  known  among  mechanics  by  the  name 
of  wipers. 

Another  loom,  the  origin  of  which  I  be- 
lieve to  be  English,  but  which  has  lately 
been  introduced  in  Scotland  to  a  consi- 
derable extent,  is  the  crank  loom.  The 
last  invented  by  Mr.  Johnson,  and  brought 
into  practice  by  Mr.  Pcobert  ShirrefT,  for 
which  also  a  patent  has  been  granted,  is 
the  vertical  loom. 

In  these  looms,  different  modes  of  con- 
struction have  been  adopted,  without  any 
materal  deviation  from  the  same  general 
principle.  The  plan  of  weaving  by  power, 
has  been  so  recently  introduced,  and  hi- 
therto confined  to  so  few  hands,  that  it  is 
4  B 


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natural  to  suppose,  that  many  improve  I 
ments  still  remain  to  be  made,  and  that  | 
much  difference  of  opinion,  respecting- j 
the  relative  merits  of  the  different  plans  j 
does,  and  will,  for  a  considerable  time, 
exist.    1  shall,  tor  these  reasons,  confine 
my  Observations  and  descriptions  to  the 
pr  ncipal  moving'  pans  of  each,  leaving 
the  connections,  and  framing  of  the  ma- 
chines, lo  the  judgment  and  discretion 
of  those,  who  may  apply  them  to  prac- 
tice. 

With  the  exception  of  the  motion  for 
winding  up  the  cloth,  and  unwinding  the 
■warp,  which  is  rotary  on  the  axes  of  the 
beams,  an  the  motions  of  the  loom  are  al- 
ternate, or  reciprocating.  The  two  me- 1 
thods,  most  common  among  mechanics, 
of  producing  these  motions,  are  cranks 
and  wipers,  or  excentric  wheels 

The  reciprocating  motion  derived  from 
the  evolution  of  a  crank  on  its  own  axis, 
is  not  uniform,  but  accelerated  at  one 
time,  and  retarded  at  another.  By  means 
of  wipers,  the  motion  may  be  made  uni- 
form, accelerated,  or  retarded,  at  any  part 
of  the  revolution,  according  to  the  effect 
which  the  engineer  wishes  to  produce. — 
In  many  machines,  this  property  gives 
the  wiper  a  very  decided  advantage  over 
the  crank:  but  in  the  weaving  loom,  the 
retardation  of  the  crank,  so  far  from  being 
disadvantageous,  is  of  considerable  ser- 
vice. 

In  Plate  22,  23,  and  24,  will  be  found 
representations  of  the  chief  working  parts 
of  the  different  power  looms  ;  and  as  the 
vertical  loom  is  the  one  most  recently  in- 
vented, 1  have  given  a  profile,  and  trans- 
verse elevation  of  it,  from  drawings,  for 
which  1  am  indebted  to  Mr.  Shirjreff. 

Wiper  Loom. 

Plate  22,  Fig.  1.  Weaving,  is  a  repre- 
sentation of  the  way  of  moving  the  hed. 
dies  in  this  loom,  so  as  to  open  the  sheds. 
This  figure  is  a  profile  elevated  section  of 
the  heddles  L.,  Fig.  9,  connected  with  the 
treddlts  R,Fig.l,  much  in  the  same  way  as 
in  a  common  loom.  In  some  power  looms, 
the  cords  above  the  heddles,  pass  oyer  pul- 
lies,  as  in  the  figure;  in  others,  Jacks  are 
used,  as  in  the  common  loom.  i  he  mo- 
tion is  given  to  this  loom,  by  a  horizontal 
cross  shaft,  upon  which  are  a  number  of 
wipers.  A  section  of  this  shaft,  with  the 
double  wiper,  winch  sinks  the  two  tred- 
dles  alternately,  is  represented  at  S. 

These  wipers  may  be  constructed  for 
any  range  of  motion,  in  the  following 
manner.  Describe  a  circle  of  a  conveni- 
ent diameter  on  the  piece  of  wood,  or  oth- 
er substance,  which  is  to  form  the  wiper. 
Having  considered  the  range  which  the 


wiper  is  to  communicate  to  the  treddle, 
draw  a  diameter  line  through  the  circle, 
and  upon  this  line,  set  off  the  length  of 
the  proposed  range  on  the  outside  of  the 
circle.  At  this  point,  describe  a  second 
circle  concentric  with  the  first,  and  divide 
the  circumference  into  a  great  number 
of  equal  parts.  From  the  centre  draw  a 
radius  to  each  of  these  divisions,  and  the 
wiper  will  be  ready  for  setting  off.  If  a 
uniform  reciprocating  motion  is  wanted, 
during  the  whole  revolution  of  the  wiper, 
it  is  only  necessary  to  divide  the  space 
between  the  inner  and  outer  circle,  into 
as  many  equal  parts  as  half  the  number 
of  radii.  Set  off'  one  of  these  parts  on  the 
|  first  radius  line,  two  on  the  second,  three 
on  the  third,  and  so  on,  until  the  whole 
are  set  off,  when  the  semi-circumference 
of  the  wiper  will  be  worked  off ;  and  the 
same  operation  reversed,  will  give  the 
other  or  returning  side.  This  forms  ex- 
actly the  common  heart  traverse.  In  the 
figure,  a  few  radii  are  drawn  upon  S,  to 
show  the  principle ;  but  it  will  appear 
that  each  of  these  two  wipers  is  con- 
structed on  half  the  circle,  so  that  each 
may  operate  alternately  on  its  respective 
treddle,  when  both  sheds  will  be  opened 
by  one  revolution  of  the  shaft.  As  it  is 
necessary  that  the  shed  should  remain 
open,while  the  shuttle  is  passing  through, 
all  the  range  must  be  set  oft",  some  time 
before  the  wiper  arrives  at  the  centre,and 
the  extremity  left  circular,  to  suspend  the 
motion  for  the  time  required.  This  is  the 
case  with  the  two  wipers  at  S. 

Fig.  2.  is  a  profile  elevation  of  the  ap- 
paratus, for  moving  the  lay.  E  is  the  lay 
vibrating  on  its  centres  above,  as  in  the 
common  loom.  1  he  lay  is  pulled  back 
by  the  operation  of  the  wipers  S,  upon  the 
treddle  11,  by  means  of  the  connection  re- 
presented in  the  figure.  After  the  shut- 
tle has  passed  through  the  shed,  the  lay 
is  pulled  forward  by  a  weight  attached  to 
a  cord  or  belt,  passing  over  a  pully,  as  re- 
presented. These  wipers  are  also  con- 
structed on  semi-c  rcles,  that  the  lay  may- 
operate  twice  in  one  revolution,  as  well 
as  die  heddles.  Both  wipers,  however, 
operate  upon  the  same  treddle,  as  they 
are  only  intended  to  repeat  the  same  mo- 
tion, while  those  which  move  the  heddles 
must  reverse  the  shed.  There  is  an  ap- 
paratus of  this  kind  at  each  side  of  the 
loom,  to  keep  the  lay  steady.  The  wipers 
for  this  motion  are  upon  the  same  shaft, 
with  those  for  the  heddles.  In  some  powei 
looms,  the  swords  of  the  lay  are  reversed, 
and  move  in  centres  below.  There  are 
different  ways  for  driving  the  shuttle.  In 
some,  the  driver  cords  are  attached  to 
the  point  of  a  lever,  with  two  cross  tails, 


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AVE  A. 


as  represented  by  Fig-.  3.  This  lever, 
being  placed  perpendicularly  under  the 
warp,  with  a  flat  side  parallel  to  the  hori- 
zontal shaft,  and  moving  freely  on  its  cen- 
tre, the  cross  tails  are  alternately  struck 
by  two  pieces  of  iron,  fixed  to  the  shaft, 
as  represented  at  U,  in  Fig.  7.  and,  by 
moving  the  lever,  drive  the  shuttle  across 
the  web.  In  other  looms,  two  treddles 
are  used,  which  are  moved  alternately, 
by  wipers  on  the  shaft,  and  produce  the 
same  effect.  Various  means  are  also  used 
for  winding  up  the  cloth,  of  which  some 
notice  will  be  taken,  when  we  come  to 
consider  the  vertical  loom.  In  the  mean 
time,  we  proceed  to  the 

Crank  Loom. 
In  this  loom  no  treddles  are  necessary, 
for  the  motion  is  communicated  directly 
by  the  cranks.  Fig.  4.  is  a  profile  of  the 
heddles,  and  section  of  the  heddle  crank 
shaft.  The  shape  of  the  cranks  will  ap- 
pear by  Fig.  5.  where  a  small  portion  of 
the  shaft  is  represented  in  a  transverse 
direction.  Fig.  6  is  a  profile  of  the  lay, 
and  section  of  the  lay  crank  shaft.  Fig. 

7.  is  a  transverse  view  of  the  shaft,  to 
show  the  way  of  disposing  the  cranks.  It 
will  be  obvious,  that  in  this  loom  two  ho- 
rizontal shafts  are  necessary,  for  only  one 
stroke  of*  the  lay,  can  be  effected  by  a 
whole  revolution  of  the  lay  shaft;  where- 
as in  the  wiper  loom,  the  double  wiper 
gives  two.  These  shafts  are  placed  pa- 
rallel to  each  other,  and  on  the  same  le- 
vel, the  heddle  cranks  being  perpendicu- 
larly under  the  heddles,and  the  lay  cranks 
behind.  As  it  is  necessary  that  the  lay 
shaft  should  revolve  twice,  while  the  hed- 
dle shaft  revolves  once,  the  latter  takes 
its  motion  from  the  former,  by  a  spur 
wheel  and  pinion,  as  represented  by  Fig. 

8.  The  wheel  containing  double  the  num- 
ber of  teeth  of  the  pinion,  is  fixed  on  the 
heddle  shaft,  the  pinion  on  the  lay  shaft 
The  pully,  which  receives  the  motion 
from  the  power,  is  also  on  the  lay  shaft. 
The  swords  of  the  lay  are  lengthened  be- 
low the  boxes,  to  bring  the  connecting 
rods  level  with  the  shaft,  and  these  con- 
necting rods,  in  both  motions,  are  usually 
of  iron.  The  shuttle  motion  is  effected 
by  either  of  the  two  plans  formerly  de- 
scribed. We  now  come  to  the  last  in- 
vention, the 

Vertical  Loom. 
Plates  23,  and  24,  are  elevations 
of  two  of  these  looms,  constructed  at  op- 
posite sides  of  the  same  frame,  and  will 
convey  a  tolerably  correct  idea  of  their 
framing  appearance.  Plate  24,  Fig.  1.  is 
a  transverse  elevation  of  one  end.  The 


figures,9to  13,  plate  22,  inclusive,  are  the 
several  working  parts.  The  whole  reci- 
procating motions  of  the  vertical  loom, 
are  also  effected  by  cranks,  and  these 
cranks  are  upon  two  shafts. 

A  is  a  balance  wheel  on  the  lay  crank 
shaft,  one  side  of*  which  is  so  much  hea- 
vier than  the  other,  as  to  counterpoise 
the  weight  of  the  lay  and  swords,  and 
make  them  ascend  and  descend  with 
equal  ease.  The  swords  rise  and  sink 
between  sheers,  or  guides,  to  keep  them 
steady. 

Ii  is  the  pully  which  takes  the  motion 
from  the  power,  and  which  is  also  on  die 
lay  shaft 

C  is  the  lay  shaft,  with  a  crank  at  ei- 
ther end,  similar  to  those  of  the  crank 
loom. 

D  is  a  wheel  on  the  heddle  shaft,  re- 
ceiving motion  fiom  a  pinion  of  half  the 
number  of  teeth  on  the  lay  shaft,  as  in  the 
crank  loom. 

E  is  the  lay  and  boxes,  with  the  reed 
placed  horizontally,  and  on  which  the 
shuttle  runs. 

F  is  the  yarn  beam,  from  which  the 
warp  ascends  perpendicularly  through 
the  mounting. 

G  is  the  cloth  beam  above,  for  receiv- 
ing the  cloth  when  woven. 

H  the  wheels  by  which  the  cloth  is 
wound  up. 

I  is  the  lever  and  fork,  for  engaging  or 
disengaging  the  machine  at  pleasure. 

K  is  a  catch,  by  which  the  loom  will 
be  instantly  stopped,  if  the  shuttle  should 
remain  in  the  shed.  All  the  power  looms 
have  contrivances  of  this  kind,  which 
will  be  more  particularly  noticed  after- 
wards. 

The  nature  and  construction  of  each 
particular  motion  will  appear  very  plain- 
ly, by  inspecting  the  supplementary  fi- 
gures. 

Fig.  9,  Plate  22,  contains  a  profile  of 
the  horizontal  heddles,  and  the  apparatus 
for  moving  them. 

At  L  are  the  heddles,  placed  horizon- 
tally, and  guided  by  belts,  passing  over 
pullies  before  and  behind.  To  one  of 
these  belts  is  attached  one  end  of  the 
bended  lever  M,  moving  freely  on  its  cen- 
tre, and  the  other  end  of  which  is  con- 
nected with  the  crank  N.  The  shape  of 
this  shaft  and  crank,  will  be  plainly  seen 
in  Fig.  10.  Besides  the  crank  for  the  hed- 
dles, upon  this  shaft  is  a  projecting  stud 
P,  operating  like  a  crank  for  giving  mo- 
tion to  the  shuttle. 

Fig.  11.  is  a  profile  elevation  of  the  ap- 
paratus by  which  the  shuttle  motion  is 
communicated.  O  is  a  sliding  bar  which 
moves  freely  in  two  bushes  backward  and 


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forward.  Upon  the  edge  of  this  slider,  is 
a  rack  which  moves  a  pinion  Q,  fixed  up- 
on an  upright  shaft,.on  the  upper  part  of 
which  is  a  cross  lever,  to  which  are  at- 
tached two  leather  thong's,  which  are  al- 
so connected  with  the  drivers.  The  stud 
P,  the  end  of  which  appears  here,  like  a 
round  dot,  moving  round  in  a  hollow  el- 
liptical piece,  forming  part  of  the  slider, 
alternately  moves  it  rapidly,  backwards 
and  forwards,  by  means  of  the  catches 
above  and  below.  This  motion  drives  the 
cross  lever  upon  the  top  of  the  upright 
shaft,  to  the  right  and  left  alternately,  by 
means  of  the  pinion  Q,  and  thus  the  mo- 
tion is  communicated  to  the  drivers. 

Fig.  12.  is  a  ground  plan  of  the  rack  and 
pinion. 

Fi^;.  13.  is  an  outline  of  the  plan  for 
winding  up  the  cloth.  On  the  axis  of  the 
cloth  beam  is  fixed  a  wheel,  on  the  out- 
side of  which  is  a  ratchet  wheel,  loose 
upon  the  axis.  This  ratche  ,  one  tooth 
of  which  is  represented,  is  moved  by  a 
catch,  jointed  to  the  end  of  a  spring  con- 
nected with  a  lever ;  the  other  end  of  this 
lever  is  connected  with  the  lay  This  soring 
may  be  siack^ned,  or  stiffened  at  pleasure. 
Every  time  the  lay  rises,  the  spring  and 
lever  are  pulled  down,  to  move  the  racket 
one  tooth  ;  but  the  spring  is  made  suf- 
ficiently slack,  to  yield  without  mov- 
ing the  racket,  unless  assisted  by  the 
stroke  of  the  reed,  upon  the  fell  of 
the  cloth.  Consequently,  if  the  weft 
breaks,  no  winding-up  motion  is  produc- 
ed. This  is  very  necessary;  for,  were 
the  loom  to  go  a  shot  or  two  without  weft, 
and  the  cloth  to  be  wound  up,  it  must 
either  be  let  back,  or  a  large  unweftcd 
interval  would  be  produced.  Upon  the 
ratchet  is  fixed  a  pinion,  which  moves  a 
wheel  turning  loosely  upon  a  stud.  Ano- 
ther pinion,  fixed  to  this  wheel,  gives  the 
motion  to  the  fast  wheel,  on  the  axis  of 
the  cloth  beam,  and  consequently  to  the 
beams.  The  relative  numbers  of  these 
wheels  and  pinions,  must  depend  on  the 
quantity  ot  weft  in  a  given  space,  and  they 
must  be  fitted  on,  so  as  to  be  easily  altered 
at  pleasure- 
In  all  the  different  experiments  upon 
weaving  by  power,  hitherto  made,  it  has 
been  found  advantageous  to  confine  the 
shuttle  when  lodged  in  either  box,  to  pre- 
vent it  from  recoiling.  This  has  been  ef- 
fected by  a  circular  piece  of  wood,  press- 
ed through  one  of  the  edges  of  the  box 
by  a  slight  spring,  which  yields  to  the 
pressure  of  the  shuttle  when  entering, 
and  by  its  friction,  prevents  the  recoil.  It 
is  also  ma'erial  to  disengage  the  loom 
from  the  power  instantly,  if  the  shuttle 
should  stop  in  the  shed  ;  "for  if  driven  up 


by  the  lay,  much  damage  will  be  the  pro- 
bable  consequence.  This  disengaging 
mot  ion,  is  taken  from  these  springs,  which 
are  connected  by  bended  levers,  and  a 
wire  across  the  lay,  so  that  either  will  ope- 
rate. In  the  vertical  loom,  the  disengag- 
ing lever  I,is  strongly  pressed  by  a  spring, 
to  force  out  the  driving  pully,  whenever 
the  catch  above  is  lifted.  To  the  spring 
for  securing  the  shuttle,  an  upright  piece 
of  iron  K,  moving  in  a  joint  is  attached. 
When  the  spring  is  pressed  back  by  the 
shuttle,  the  upper  part  of  this  is  thrown 
forward,  clear  of  a  notch  in  an  upright 
slide,  attached  to  the  disengaging  catch  ; 
but  if  one  spring  is  not  pressed,  K  not 
being  thrown  forward,  will  strike  the 
notch,  and  instantly  disengage  the  ma- 
chine. The  contrivances  for  disengaging 
the  other  looms,  are  exactly  upon  the 
same  principle,  a  little  differently  modifi- 
ed, to  suit  the  construction  of  the  looms. 

When  the  vertical  loom  is  to  work  yarn 
which  requires  dressing,  an  iron  roller  is 
placed  where  the  yarn  beam  is  represent- 
ed, and  the  beam  itself  in  a  small  addi- 
tional frame,  parallel  to,  and  on  a  level 
with  the  roller,  so  that  the  part  to  be 
dressed  is  in  a  horizontal  position,  as  in  a 
common  loom.  Every  power  loom  is  ge- 
nerally  furnished  with  a  circular  fan,  such 
as  formerly  described,  placed  under  the 
warp,  and  which  is  occasionally  set  in 
motion,  to  dry  the  yarn  after  being  dress- 
ed. Two  pair  of  temples  are  generally 
used  in  power  weaving. 

It  is  not  easy  to  decide,  justly  upon  the 
comparative  merits  of  these  looms,  and 
upon  this  subject  a  considerable  differ- 
ence of  opinion  still  prevails  The  wipers 
are,  without  doubt,  susceptible  of  a  mo- 
dification/if  the  motion,  to  suit  different 
fabrics,  in  a  much  greater  degree  than  the 
cranks  ;  but  in  the  coarse  fabrics,  hither- 
to woven  by  power,  the  crank  motions 
are  found  sufficiently  correct.  The  mode 
of  striking  up  the  lay,  by  means  of  a 
weight,  js  found  productive  of  one  very 
considerable  inconvenience.  The  force  of 
the  lay  has  a  tendency  to  slacken,  and, 
consequently,  to  spread  the  warp,  and 
when  the  shed  closes  in  this  state,  the 
threads  are  apt  to  obstruct  each  other, 
and  occasion  breaking,  A  very  simple 
and  ingenious  apparatus,  has  lately  been 
added  to  the  vertical  loom,  to  obviate 
this  disadvantage,  which  also  attends  the 
crank  loom,  although  not  to  an  equal  de- 
gree. This  is  merely  a  flat  board,  the 
edge  of  which  is  parallel  to  the  warp,  and 
which  moves  on  centres.  By  means  of 
two  bended  levers,  connected  by  cords, 
or  thongs,  to  the  lay,  this  board  presses 
the  warp  when  the  shed  closes,  and  re- 


wj:a 


AVE  A 


cedes  from  it  when  the  shed  is  opened.— 
Thus  the  warp  is  kept  uniformly  tight. 
The  same  contrivance  might  easiiy  be  ap- 
plied to  either  of  the  other  looms. 

The  vertical  loom  certainly  appears  to 
possess  some  decided  advantages  over 
the  others. 

lstly,  It  occupies  a  much  smaller  space 
of  room,  and  consequently,  in  a  large 
manufactory,  a  considerable-  saving  might 
be  effected,  both  in  the  expense  of  build- 
ing, and  in  that  of  shafts  or  other  mili- 
work. 

2dly,  From  the  shuttle  running  upon 
the  reed,  a  larger  pirn  may  be  used,  with- 
out any  risk  of  injuring  the  warp  by  fric- 
tion. 

3dly,  When  it  is  necessary  to  dress 
the  warp,  which,  in  power  weaving,  is 
usually  done  without  stopping  the  loom, 
it  presents  the  following  Very  important 
advantage.  The  operator,  while  dressing, 
remains  exactly  in  the  same  situation  as 
when  attending  the  working,  and  can, 
therefore,  see  in  a  moment,  any  thing 
Which  may  go  wrong  ;  whilst  in  the  other 
looms,  the  person  while  attending  the 
working,  must  be  in  front,  and  when  dres- 
sing, behind,  where  it  is  very  difficult  to 
see  any  obstruction,  which  may  happen 
before  the  reed. 

Practical  experience  has  proven,  the 
danger  and  inconvenience  of  working  a 
loom  beyond  a  proper  rate  of  velocity,  as 
highly  injurious  to  the  manual  op  ration, 
and  I  am  fully  convinced,  it  must  be  equal- 
ly, if  not  more  prejudicial,  in  weaving  by 
power.  It  has  been  common  to  drive 
power  looms,  at  the  rate  of  80  or  90  shois 
per  minute,  and  attempts  have  even  been 
made,  to  accelerate  this  velocity  much 
beyond  100  shots.  Mechanics  know  that 
even  rotatory  motion,  when  urged  beyond 
a  moderate  speed,  always  fails  in  produc- 
ing the  effect  expected.  This  has  been 
sufficiently  proved  in  spinning,  where  al- 
most all  the  motions  are  rotatory.  In 
weaving,  where  there  are  no  less  than 
three  reciprocating  motions,  the  effect 
must  be  still  more  injurious,  especially  in 
the  lay  and  heddle  motions.  The  shut 
tie,  indeed,  may  be  driven  with  consider- 
able swiftness,  for  no  injury  can  arise 
from  this,  unless  the  shuttle  is  thrown  out 
of  the  box,  or  the  weft  too  much  strained 
and  frequently  broken.  Suppose,  a  1000 
4-4th  shawl  cloth,  with  1200  weft,  to  be 
woven  at  the  rate  of  80  shots  per  minute. 
This  will  give  a  yard  in  30  minutes,  or  24 
yards  per  day  of  12  working  hours,  it' no 
stop  were  to  take  place.  1  cannot  state 
with  certainty,  what  has  been  the  great- 
est quantity  of  cloth  of  this  description, 
produced  by  power  looms.  The  average 


quantity  on  the  vertical  loom,  I  have 
been  informed,  is  about  15  yards,  so  that, 
if  the  loom  works  at  the  velocity  quoted, 
more  than  one-third  of  the  time  must  be 
lost  by  stopping.  Besides,  1  do  not  think 
that  goods  of  this  description  have,  in  ge- 
neral, so  much  weft,  as  I  have  taken  in 
the  calculation.  Upon  the  whole,  I  should 
suppose  70  or  80  shots  to  be  the  maxi- 
mum of  velocity,  at  which  it  is  prudent 
to  drive  a  power  loom,  even  with  the 
coarsest  and  strongest  materials  ;  and  if 
these  looms  are  applied  to  weave  finer 
and  lighter  fabrics,  I  suspect  even  this 
velocity  must  be  considerably  diminish- 
ed. 

The  last  plans  of  economy  in  weaving, 
which  it  will  be  necessary  to  discuss,  are 
those  which  relate  to  the  insertion  of  the 
weft.  The  process  of  winding  the  weft 
upon  the  pirn,  whether  from  the  hank  or 
the  cop,  is  tedious,  and  consequently  ex- 
pensive. Two  means  of  reducing  this 
expense,  have  been  devised.  The  first  of 
these  is,  by  placing  the  cop  itself  in  the 
shuttle  upon  aske\ver,by  which  the  whole 
expense  of  winding  is  saved.  As  the  cops, 
however,  are  generally  too  large  for  an 
ordinary  shuttle,  it  has  been  usual  to 
compress  them.  This  is  effected  by  means 
of  two  hollow  inverted  cones,  generally 
of  brass,  with  a  hole  through  the  vertex 
of  each,  to  admit  the  skewer,  the  two 
cones  are  pressed  together  by  means  of 
a  lever  or  screw  The  cop,  being  between 
the  cones,  is  thus  compressed  to  a  much 
smaller  space,  than  it  originally  occupied. 
The  compression  is  most  effectual,  when 
tiie  cop  has  been  boiled,  but  this  can  only 
be  done  when  the  weft  is  to  be  inserted 
in  a  wet  state. 

Machines  have  also  been  constructed 
for  winding  a  number  of  pirns  at  the  same 
time.  The  principle  is  entirely  the  same 
with  that  of  the  machine,  for  winding  the 
warp  bobbins  The  only  difference  is  in 
the  shape  of  the  traverse,  which  must  be 
constructed  to  wind  the  yarn  in  the  form 
of  a  cone,  instead  of  being  flat  or  barrel 
shaped.  Those  which  I  have  seen  are 
turned  by  the  hand,  which  1  cannot  think 
is  proper,  for  the  same  reason  which  I 
stated  before ;  namely,  that  in  all  these 
machines,  the  person  who  attends  ought 
to  have  both  hands  free,  and  should  be 
at  liberty,  to  shift  from  one  part  of  the 
machine  to  another,  to  remove  obstruc- 
tions, and  knot  broken  threads.  I  do 
not  think  that  these  machines  are,  as 
yet,  very  generally  employed,  and,  per- 
haps, they  have  not  yet  reached  such  a 
state  of  improvement,  as  to  render  the 
use  of  them  an  object  of  much  impor- 
tance, in  point  of  economy. 


AVEL 


WEL 


Having-  thus  given  a  concise  treatise  on 
some  of  the  most  important  parts  in  weav- 
ing, we  are  obliged  for  want  of  room,  to 
conclude,  referring  the  reader  who  is  de- 
sirous of  acquainting  himself  more  fully 
on  this  subject  to  a  book  entitled  "  Prac- 
tical and  Descriptive  Essays  on  the  Art 
of  Weaving,  by  John  Duncan,"  where  he 
will  find  a  full  and  complete  treatise  on 
every  part  of  this  ingenious  and  interest- 
ing art. 

WEDGE.    See  Mechanics. 

WEED-ASHES,  are  a  kind  of  wood 
ashes  not  lixivated,  but  repeatedly  wet- 
ted with  the  lye  of  wood-ashes,  and  cal- 
cined to  a  degree,  so  as  to  vitrify  ;  on  this 
account  it  is  difficult  to  extract  their 
salt. 

WELD,  is  a  plant  cultivated  in  Kent, 
Herefordshire,  and  many  other  parts  of 
this  kingdom.  It  is  likewise  very  com- 
mon in  the  environs  of  Paris,  in  most  of 
the  French  provinces,  and  in  a  great  part 
of  the  rest  of  Europe  It  pushes  out  long 
narrow  leaves,  of  a  lively  green.  From 
the  midst  of  these  leaves  the  stalk  rises 
to  the  height  of  three  or  four  feet,  fre- 
quently branchy,  and  furnished  with 
leaves,  narrow,  like  the  radical  ones,  but 
shorter  as  they  approach  the  flowers, 
which  are  disposed  in  long  spikes.  The 
whole  of  the  plant  is  used  for  dyeing  yel- 
low ;  though  some  assert  that  the  seeds 
only  afford  the  colouring  matter. 

Two  sorts  of  weld  are  distinguished : 
the  bastard  or  wild,  which  grows  natural- 
ly in  the  fields  ;  and  the  cultivated,  the 
stalks  of  which  are  smaller,  and  not  so 
high.  For  dyeing,  the  latter  is  preferred, 
as  abounding  more  in  colouring  matter. 
The  more  slender  the  stalk,  the  more  it  is 
valued. 

When  the  weld  is  ripe,  it  is  pulltd, 
dried  and  made  into  bundles,  in  which 
state  it  is  used. 

When  the  decoction  of  weld  is  very 
strong,  it  has  a  yellow  colour  inclining  to 
brown.  If  it  be  greatly  diluted  with  wa- 
ter, its  yellow,  which  is  more  or  less  pale, 
inclines  a  little  to  green. 

If  a  little  alkali  be  added  to  this  de- 
coction, its  colour  grows  deeper,  and  af- 
ter a  certain  time,  a  little  ash-coloured 
precipitate  falls  clown,  which  is  not  solu- 
ble m  alkalies- 

Acids  in  general  render  its  colour 
pales-,  and  occasion  a  little  precipitate, 
which  will  dissolve  in  alkalis,  giving  them 
a  yellow  colour  inclining  to  brown. 

A  um  forms  with  it  a  yellowish  preci- 
pitate, and  the  liquor  retains  a  fine  lemon- 
colour.  If  a  solution  of  alkali  be  poured 
into  this  liquor,  a  whitish  yellow  precipi- 


tate, soluble  in  alkalies,  is  thrown  down, 
but  the  liquor  still  remains  coloured. 

Solution  of  common  salt,  or  of  sal  am- 
moniac,  renders  the  liquor  turbid,  and  its 
colour  at  hi  st  a  little  deeper ;  by  degrees 
a  deep  yellow  precipitate  forms,  and  the 
supernatant  liquor  retains  a  pate  yellow 
colour,  a  little  inclining  to  green. 

Solution  of  tin  produces  a  copious 
bright  yellow  precipitate.  The  liquor  re- 
mains a  long  time  turbid,  but  slightly  co- 
loured. 

Sulphate  of  iron  produces  a  plentiful 
dark  grey  precipitate,  and  the  superna- 
tant liquor  is  brownish. 

Sulphate  of  copper  occasions  a  brown- 
ish green  precipitate,  and  the  liquor  pre- 
serves a  pale  green  colour. 

The  yellow  communicated  to  wool  by 
weld,  has  little  permanency,  if  the  wool 
be  not  previously  prepared  by  some  mor- 
dant. For  this  purpose  alum  and  tartar 
are  used,  by  means  of  which  this  plant 
gives  a  very  pure  yellow,  which  has  the 
advantage  of  being  permanent. 

For  the  boiling,  winch  is  conducted  in 
the  common  way,  Hellot  directs  lour 
ounces  of  alum  to  every  pound  of  wool, 
and  only  one  ounce  of  tartar :  many  dyers 
how  ever,  use  half  as  much  tartar  as  alum. 
Tartar  renders  the  colour  paler,  but  more 
hveiy. 

For  the  welding,  that  is,  for  the  dyeing 
with  v;eid,  the  plant  is  boiled  in  a  fresh 
bath,  enclosing  it  in  a  bag  of  thin  linen, 
and  keeping  it  from  rising  to  the  top  by 
means  oi  a  heavy  wooden  cross.  Some 
dyers  boil  it  till  it  sinks  to  the  bottom  of 
ttie  copper,  and  then  let  a  cross  down  up- 
on it;  others,  when  it  is  boiied,  take  it 
out  with  a  rake,  and  throw  it  away. 

Hellot  directs  five  or  six  pounds  of  weld 
for  every  pound  of  cloth ;  but  dyers  sel- 
dom use  so  much,  contenting  themselves 
with  three  or  four  pounds,  or  even  much 
less.  Many  indeed  add  to  the  weld  a 
little  quick-lime  and  ashes,  which  favour 
the  extraction  of  the  colouring  mutter, 
and  heighten  its  colour,  but  at  the  same 
time  render  it  liable  to  be  changed  by  the 
action  of  acids.  The  quantity  of  weld, 
however,  ought  to  be  proportionate  to 
the  depth  oi  the  siiade  to  be  obtained. 

Lighter  and  brighter  shades  may  be 
obtained  by  dyeing  after  deeper  ones, 
adding  water  at  eacn  dipping,  and  keep- 
ing tne  bath  boiling;  but  light  shades 
procured  in  this  way  are  rot  so  lively  as 
when  fresh  baths  are  used,  proportioning 
the  quantity  of  weld  to  the  depdi  of  the 
shade. 

Common  salt  added  to  the  weld-bath 
renders  its  colour  richer  and  deeper; 


WEL 


WEL 


sulphate  of  lime,  or  gypsum,  also  deep- 
ens it;  but  alum  renders  it  paler  and 
more  lively,  and  tartar  still  paler.  Sul- 
phate of  iron  makes  it  incline  to  brown. 

The  shades  obtained  from  weld  may 
be  modified,  by  such  additions,  by  the 
proportion  of  the  weld,  by  the  length  of 
the  operation,  and  by  the  mordants  em- 
ployed in  preparing  the  stuff.  Thus, 
Scheffer  says,  that  by  boiling-  the  wool 
two  hours  with  a  fourth  its  weight  of  so- 
lution of  tin,  and  the  same  of  tartar, 
washing  it  and  boiling  it  fifteen  minutes 
with  an  equal  weight  of  weld,  it  will  take 
a  line  yellow,  which,  however,  will  not 
penetrate  its  internal  texture.  Mr.  Poer- 
ner  also  directs  the  cloth  to  be  prepared 
as  for  dyeing  scarlet.  By  these  means 
greater  brightness  and  permanency  are 
given  to  the  colour,  which  cateris paribus, 
is  at  the  same  time  lighter. 

The  colour  may  be  modified  also  by 
passing  the  cloth,  when  it  comes  out  of 
the  dye,  through  another  bath.  Thus,  to 
produce  a  golden  yellow,  the  cloth,  when 
it  comes  out  of  the  welding-,  may  be  pass- 
ed through  a  slight  madder-bath ;  and 
for  a  tawny,  through  a  bath  made  with  a 
little  soot. 

To  dye  silk  plain  yellow,  in  general  no 
other  ingredient  than  weld  is  used.  The 
silk  ought  to  be  scoured  in  the  propor- 
tion of  twenty  pounds  of  soap  to  the  hun- 
dred, and  afterwards  alumed  and  refresh- 
ed, that  is,  washed  after  the  aluming. 

A  bath  is  prepared  with  two  pounds  of 
weld  for  each  pound  of  silk,  which,  after 
a  quarter  of  an  hour's  boiling,  is  to  be 
passed  through  a  sieve  or  cloth  into  a 
vat.  When  it  is  of  such  a  temperature 
as  the  hand  can  bear,  the  silk  is  put  in, 
and  turned  till  the  colour  becomes  uni- 
form. During  this  operation  the  weld  is 
boiled  a  second  time  in  fresh  water ; 
about  half  of  the  first  bath  is  taken  out, 
and  its  place  supplied  by  a  fresh  decoc- 
tion. This  fresh  bath  may  be  used  a  lit- 
tle hotter  than  the  former ;  too  great  a 
degree  of  heat,  however,  must  be  avoid- 
ed, that  no  part  of  the  colour  already  fix- 
ed may  be  dissolved  ;  it  is  to  be  turned  as 
before,  and  in  the  mean  time  a  quantity 
of  the  ashes  of  wine  lees  is  to  be  dissolved 
in  a  part  of  the  second  decoction ;  the 
silk  is  to  be  taken  out  of  the  bath,  that 
more  or  less  of  this  solution  may  be  put 
in,  according  to  the  shade  required  Af- 
ter it  has  been  turned  a  few  times,  a  hank 
is  wrung  with  the  pin,  that  it  may  be  seen 
whether  the  colour  be  sufficiently  lull, 
and  have  the  proper  gold  cast ;  if  it  should 
not,  a  little  more  of  the  alkaline  solution 
is  added,  the  effect  of  which  is  to  give  the 
colour  a  gold  cast,  and  to  render  it  deep- 


er. In  this  way  the  process  is  to  be  con- 
tinued, until  the  silk  has  attained  the  de- 
sired shade :  the  alkaline  solution  may 
also  be  added  along  with  the  second  de- 
coction of  the  weld,  always  taking  care, 
that  the  bath  is  not  too  hot. 

If  we  wish  to  produce  yellows,  with 
more  of  a  gold  or  jonquile  colour,  a  quan- 
tity of  anotta,  proportioned  to  the  shade 
required,  must  be  added  to  the  bath  along 
with  the  alkali. 

For  the  light  shades  of  yellow,  such  as 
pale  lemon,  or  canary-bird  colour,  the  silk 
ought  to  be  scoured  as  for  blue,  because 
the  shades  are  more  beautiful  and  trans- 
parent in  proportion,  as  the  ground  on 
which  they  are  laid  are  whiter.  The 
strength  of  the  bath  is  proportioned  to 
the  shade  we  wish  to  obtain ;  and  if  we 
intend,  that  the  yellow  should  have  a 
tinge  inclining  to  green,  more  or  less  of 
the  indigo  vat  is  added,  if  the  silk  has  not 
been  azured.  To  prevent  the  sluides  from 
being  too  deep,  the  silk  may  be  more 
slightly  alumed  than  usual. 

Scheffer  directs,  that  the  silk  should  be 
soaked  twenty-four  hours  in  a  solution  of 
tin,  made  with  four  parts  of  nitric  acid, 
one  of  common  salt,  and  one  of  tin,  and 
saturated  with  tartar ;  that  it  should  be 
washed,  and  boiled  half  an  hour  with  an 
equal  quantity  of  weld  flowers.  Ue  savs, 
that  a  fine  straw-colour  is  thus  obtained, 
which  possesses  the  advantage  of  resisting 
the  action  of  acids.  By  following  this  pro- 
cess, very  little  tin -can  remain  in  the  so- 
lution, because  the  acid  of  tartar  precipi- 
tates it. 

In  dyeing  cotton  yellow,  we  begin  by 
scouring  it  in  a  bath  prepared  with  the  ley 
of  the  ashes  of  green  wood ;  it  is  then 
washed,  dried,  and  alumed  with  one- 
fourth  of  its  weight  of  alum;  after  twen- 
ty-four hours  it  is  taken  out  of  the  alum- 
ing, and  dried  without  being  washed.  A 
weld  bath  is  then  prepared,  with  the  pro- 
portion of  a  pound  and  a  quarter  of  weld 
for  each  pound  of  cotton;  in  this  tiie  cot- 
ton is  dyed,  by  being  turned  and  wrought 
in  it  until  it  has  acquired  a  proper  shade; 
it  is  taken  out  of  this  bath  to  be  soaked 
for  an  hour  and  a  half,  in  a  solution  of 
sulphate  of  copper,  in  the  proportion  of 
one-fourth  of  the  weight  of  the  cotton  ;  it 
is  then  thrown,  without  being  washed,  in- 
to a  boiling  solution  of  w  hite  soap,  made 
with  the  same  proportions.  After  being 
well  stirred,  it  is  boiled  in  it  for  nearly  an 
hour,  then  well  washed  and  dried. 

A  water-colour,  called  weld-yellow,  is 
much  used  by  paper-hanging  manufactu- 
rers. This  is  the  colouring  matter  of  weld 
precjpitated  with  an  earthy  base.  The 
following  is  given  in  the  Philosophical 


Magazine : — Into  a  copper  vessel  put  four 
pounds  of  fine  washed  whittling,  and  as 
much  soft  water,  :md  boil  them  tog-ether, 
stirring  them  with  a  deal  stick,  till  the 
whole  forms  a  smooth  mixture  ;  then  add 
gradually  twelve  ounces  of  powdered 
alum,  still  stirring,  till  the  effervescences 
ceases,  and  the  whole  is  well  mixed.  In- 
to another  copper  put  any  quantity  of 
weld,  with  the  roots  uppermost,  pour  in 
soft  water,  enough  to  cover  every  part 
containing  seed  •  let  it  boil,  but  not  more 
than  a  quarter  of  an  hour;  take  out  the 
weld  and  set  it  to  drain  ;  and  pass  the 
whole  through  flannel.  To  the  hot  mix- 
ture of  earth  and  water,  add  as  much  of 
this  decoction  as  will  produce  a  good  co- 
lour, keep  it  on  the  fire  till  it  boils,  and 
then  pour  it  out  into  a  deal  or  earthen 
vessel.  The  next  day  the  liquor  may 
be  decanted,  and  the  colour  dried  on 
chalk. 

WELDING.  Steel  being  considerably 
more  expensive  than  iron,  it  is  customary 
in  making  the  larger  and  coarser  kinds  of 
cutting  instruments,  to  form  only  the  edge 
of  steel.  The  two  bars  of  iron  and  steel 
are  first  welded  together,  and  afterwards 
forged  into  the  requisite  shape,  in  the 
usual  manner.  Highly  carbonized  steel, 
is  however  incapable  of  being  thus  united 
to  iron,  because  the  same  temperature  at 
which  iron  welds  freely,  is  that  at  which 
this  kind  of  steel  enters  into  fusion,  and 
therefore  the  first  stroke  of  the  hammer, 
will  entirely  shatter  the  steel,  and  dis- 
perse it  about  in  small  fragments.  This 
however  is  a  difficulty  which  is  well  worth 
while  taking  some  pains  to  overcome,  as 
the  efficacy  and  durability  of  instruments 
thus  composed,  materially  depends  upon 
the  goodness  of  the  steel".  The  most  ef- 
fectual way  hitherto  discovered  of  uniting 
together,  iron  and  high  ly  carbonized  steel, 
is  that  published  by  Sir  Thomas  Frank- 
land.  The  iron  is  to  be  raised  to  a  weld- 
ing heat,  in  one  forge,  and  the  steel  is  to 
be  made  as  hot  as  ii  can  bear,  without  be- 
coming very  brittle,  in  another ;  both 
pieces  are  then  to  be  quickly  brought  to 
the  anvil,  and  made  to  adhere  together  by- 
gentle  hammering. 

No  less  than  three  experiments  failed 
to  wcid  Huntsman's  cast  steel  to  iron, 
agreeably  to  Sir  Thomas  Franklan's  pro- 
cess, conducted  in  the  presence  of  Dr 
Mease,  and  at  his  request,  by  the  late  Mr. 
'Schively,  cutler,  of  Philadelphia,  and  an 
expert  "workman.  The  degrees  of  heat 
prescribed  for  both  iron  and  steel,  were 
scrupulously  attended  to. 

This  secret  process  was  reserved  for 
the  United  Stales.  Mr.  Pettibone,  now 
of  Philadelphia,  welds  cast  steel  to  iron 


with  ease  and  expedition.  He  even  plates 
clothier's  shears  with  steel,  or  plates  iron 
of  any  length  or  breadth ;  or  faces  anvils, 
hammers  or  sledges.  See  Pettibone's 
list  of  patents  in  his  "  Economy  of  Fuel." 
See  also  Iron. 

WHALE  OIL.    See  Train  Oil. 

WHEAT,  starch  from.    See  Starch. 

WHEEL  WORK.    See  Mechanics. 

WHEEL  CARRIAGE.  See  Waggon. 

WHEEL  and  AXLE.  See  Mecha- 
nics. 

WHETSTONE,  is  a  kind  of  sand  stone, 
generally  of  a  dusky  yellow  colour,  and 
is  employed  for  sharpening  knives,  and 
other  edge  tools.  Quarries  of  whetstone 
are  found  in  several  places  of  the  United 
Slates  ;  and  some  of  an  excellent  quality. 
The  red  sand  stone,  owing  to  the  scarcity 
of  the  other  description,  have  been  made 
into  grind  stones,  but  we  are  sorry  to  say 
that  the  stone,  is  too  soft  and  friable,  for 
the  purpose. 

WHBTSLATE,  called  also  novaculite 
and  Turkey  stone,  we  have  mentioned 
under  the  head  of  Turkey  stone,  is  found 
in  abundance  of  an  excellent  quality,  in 
the  United  States. 

WHEY.  See  Milk. 

WHISKEY.  See  Spirits,  Distill- 
ed 

WHITE.    See  Colour  Making. 

WHITE  COPPER.    See  Copper. 

WHITE  LEAD     See  Lead. 

WHITE  WAX.    See  Wax. 

WHITING,  is  chalk  pulverized  and 
washed,  by  which  means  it  is  freed  from 
whatever  gritty  particles  it  may  contain, 
and  afterwards  dried.  Whiting  is  used 
largeh  for  polishing  metals  and  the  like. 

WHITE  WASH,  lime  slacked  in,  and 
mixed  with  water.  White  may  be  chang- 
ed into  yellow  wash,  very  expeditiously, 
by  mixing  with  it  a  solution  of  copperas, 
and  into  green  wash,  by  mixing  it  in  the 
same  manner  with  blue  vitriol.  Either 
wash  before  it  is  used  for  washing  the 
ceilings  of  rooms  &c.  may  be  rendered 
more  durable  by  mixing  with  it  a  solution 
of  glue  The  lime  which  is  first  caustic, 
becomes  hard,  in  consequence  of  the  eva- 
poration of  the  water,  and  the  absorption 
of  carbonic  acid. 

WHITE  WASH  WITH  MILK.  See 
Colour  Making. 

WILLOW.  We  mention  this  wood  in 
this  place,  principally  on  account  of  its 
use  when  charred,  in  the  manufacture  of 
gun  powder.  Some  observations  on  this 
subject  may  be  found  in  the  article  Gun 
Powder. 

Willow  is  a  genus  of  trees  comprising 
42  species,  a  great  number  of  which  is 
indigenous,  and  many  of  which  are  useful 

f 


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WIN 


m  making  handles,  cutting  and  whetting 
boards  for  shoemakers  ;  the  bark  of  the 
species  capreata  for  tanning,  with  the  al- 
der hark  for  dyeing  linen  yarn  of  a  black 
colour ;  the  shoots  of  the  rose,  purple, 
and  red  willow  for  baskets,  cradles,  and 
other  articles  of  wicker  work  ;  the  leaves 
of  the  sweet-leafed  willow  for  yellow  dye, 
the  plant  branches  for  hampers,  the  down 
of  the  seeds  with  cotton  for  the  manu- 
facture of  stockings,  and  other  articles, 
&c. 

WINCH.    See  Mechanics. 

WIND.    See  Meteorology. 

WIND  MILL.    See  Mechanics. 

WINE,  is  an  agreeable,  spirituous  aro- 
matic liquor,  prepared  by  fermenting  the 
juices  of  sundry  vegetable  products.  The 
following  is  a  receipt  to  make  an  excel- 
lent American  wine,  by  Joseph  Cooper, 
Esq.  of  Gloucester  county,  New-Jersey. 

"I  put  a  quantity  of  the  comb,  from 
which  the,  honey  had  been  drained,  into 
a  tub,  and  added  a  barrel  of  cyder,  im- 
mediately from  the  press ;  this  mixture 
was  well  stirred,  and  left  for  one  night. 
It  was  then  strained,  before  a  fermenta- 
tion took  place ;  and  honey  was  added, 
until  the  strength  of  the  liquor  was  suffi- 
cient to  bear  an  egg.  It  was  then  put 
into  a  barrel ;  and  after  the  fermentation 
commenced,  the  cask  was  filled  every 
day,  for  three  or  four  days,  that  the  filth 
might  work  out  of  the  bung-hole.  When 
the  fermentation  moderated,  I  put  the 
bung  in  loosely,  lest  stopping  it  tight 
might  cause  the  cask  to  burst.  At  the 
end  of  five  or  six  weeks,  the  liquor  was 
drawn  off  into  a  tub,  and  the  whites  of 
eight  eggs,  well  beat  up,  with  a  pint  of 
clean  sand,  were  put  into  it.  I  then  add- 
ed a  gallon  of  cyder  spirit,  and  after  mix- 
ing the  whole  well  together,  I  returned 
it  into  the  cask,  which  was  well  cleaned, 
bunged  it  tight,  and  placed  it  in  a  proper 
situation  for  racking  off,  when  fine.  In 
the  month  of  April  following,  1  drew  it 
off  into  kegs,  for  use,  and  found  it  equal, 
in  my  opinion,  to  almost  any  foreign 
wine.  In  the  opinion  of  many  judges,  it 
was  superior. 

"This  success  has  induced  me  to  re- 
peat the  experiment  for  three  years ;  and 
1  am  persuaded,  that,  by  using  clean  ho- 
ney, instead  of  the  comb,  as  above  de- 
scribed, such  an  improvement  might  be 
made,  as  would  enable  the  citizens  of  the 
United  States  to  supply  themselves  with 
a  truly  federal  and  wholesome  wine, 
which  would  not  cost  a  quarter  of  a  dol- 
lar per  gallon,  were  all  the  ingredients 
procured  at  the  market  price ;  and  would 
have  this  peculiar  advantage  over  every 

VOL.  II. 


other  wine,  hitherto  attempted  in  this 
country,  that  it  contains  no  foreign  mix- 
ture, but  is  made  from  ingredients,  pro- 
duced on  our  own  farms.'5 

Dr.  Aigster  observes,  in  the  Gleaner  (a 
periodical  work  published  at  Pittsburg) 
that  "  The  culture  of  the  vine  has  been  by 
no  means  yet  sufficiently  tried  in  the  U. 
S.  The  attempts,  however,  made  by  the 
American  Vineyard  Society,  near  Phila- 
delphia, by  the  Swiss  settlers,  on  the 
banks  of  the  Ohio,  in  Indianna,  by  the 
Harmony  Society,  near  Pittsburg,  and  by 
Mr.  Henderson,  on  the  Juniata,  deserve 
the  greatest  praise.  The  grapes  of  all 
the  vineyards  are  greatly  deficient  in  the 
saccharine  principle,  which  is  to  furnish 
the  alcohol,  and  consequently  the  wine 
made  from  them,  is  destitute  of  body,  and 
contains  a  superabundance  of  acid. — The 
Harmony  wine  is  certainly  of  all  the  most 
palatable,  which  is  not  so  much  owing  to 
the  local  position  of  the  vineyard,  a  cir- 
cumstance  in  which  tiie  Swiss  vineyard 
has  by  far  superior  advantages,  but  to  the 
judicious  method,  and  to  the  persevering 
labour,  with  which  this  industrious  bee- 
hive conduct  their  undertakings.  All  the 
vines  hitherto  cultivated  in  this  country, 
have  been  transported  from  Europe. 
Would  it  not  be  worth  while  to  try,  how 
far  culture  could  succeed  in  improving 
our  native  grapes  \  Besides  the  various 
kinds  of  grapes  which  are  common  on 
the  east  side  of  the  Alieghanies,  we  find 
on  the  Ohio  and  the  Mississippi,  two  par- 
ticular kinds  of  vines,  the  vitis  cestivolis 
and  the  vitis  riparia.  The  grape  of  the 
latter  is  said  to  be  very  fine,  and  there  is 
every  reason  to  suppose,  that  by  careful 
culture,  it  might  be  highly  improved  in 
its  native  soil." 

We  shall  now  state  the  method,  in 
which  foreign  wines  are  obtained  from  the 
fruit  of  the  vine. 

When  the  grapes  are  sufficiently  ripe, 
they  are  gathered,  and  submitted  to  the 
action  of  a  press  ;  from  which  their  juice 
runs  into  vessels  furnished  for  that  pur- 
pose. Here  it  remains  for  several  hours, 
or  for  a  few  days,  according  to  the  tem- 
perature of  the  atmosphere.  When  the 
fermentation  commences,  the  liquor  rises, 
and  a  considerable  portion  of  fixed  air, 
or  carbonic  acid  gas,  is  evolved.  At  the 
expiration  of  some  days,  the  fermentation 
ceases.  When  the  liquor  becomes  clear, 
and  cool,  it  is  poured  into  odier  casks  or 
vessels,  where  it  undergoes  a  slight  de- 
gree of  a  new  fermentation,  in  conse- 
quence of  which,  it  becomes  divested  of 
all  feculent  particles,  while  its  taste  and 
flavour  are  remarkably  improved. 
•  4  c 


WIN 


WIN 


Dr.  Thompson  observes,  that  the  must 
of  grapes,  which  is  ti  e  juice,  is  composed 
almost  entirely  of  nne  ingredients ;  name- 
ly, water,  sugar,  jelly,  gluten,  and  tarta- 
ric acid,  partly  saturated  with  potash. 
The  quantity  of  sugar  which  grapes  ful- 
ly ripe  contain,  is  considerable  ;  it  may 
be  obtained  by  evaporating  must  to  the 
consistence  of  syrup,  separating  the  tar- 
tar which  separates,  and  then  setting  the 
must  aside.  Crystals  of  sugar  gradually 
form.  The  component  parts  of  wine, 
with  observations  on  the  subject,  are  given 
by  the  Dr.  in  the  following  words  : 

The  properties  of  wine  differ  very 
much  from  each  other,  according  to  the 
nature  of  the  grapes  from  which  the  must 
was  extracted,  and  according  to  the  man- 
ner in  which  the  process  was  conducted. 
These  differences  are  too  well  known  to 
require  a  particular  description.  But  all 
wines  contain  less  or  more  of  the  follow- 
ing ingredients;  not  to  mention  water, 
which  constitutes  a  very  great  proportion 
of  every  wine. 

1.  An  acid. — All  wines  give  a  red  co- 
lour, to  paper  stained  with  turnsole,  and  of 
course  contain  an  acid.  Chaptal  has  as- 
certained  that  the  acid  found  in  greatest 
abundance  in  wine,  is  the  malic,  but  he 
found  traces  also  of  the  citric  acid,  and  it 
is  probable  that  the  wine  is  never  entirely 
destitute  of  tartar  All  wines  which  have 
the  property  of  frothing,  when  poured  in* 
to  a  glass,  contain  also  carbonic  acid,  to 
which  they  owe  their  briskness.  This  is 
the  case  with  Champagne.  These  wines 
are  usually  weak ;  their  fermentation  pro- 
ceeds slowly,  and  they  are  put  up  in  close 
vessels  before  it  is  over.  Hence  they  re- 
tain the  last  portions  of  carbonic  acid  that 
have  been  evolved. 

2.  Alcohol. — All  wines  contain  less  or- 
more  of  this  principle,  to  which  they  are 
indebted  for  their  strength  ;  but  in  what 
particular  state  of  combination  it  exists  in 
wine,  cannot  be  easily  ascertained.  It  is 
undoubtedly  intimately  combined  with 
the  other  component  parts  of  wine;  as 
Fabi  oni  has  shown  that  it  cannot  be  sepa- 
rated by  saturating  the  wine  with  dry  car- 


bonate of  potash,  though  a  very  small  por 
tion  of  alcohol,  added  on  purpose  to  wine, 
may  be  easily  separated  by  means  of  that 
salt.  But  if  alcohol  separate  along  with 
the  carbonic  acid  during  the  fermenta- 
tion, we  can  scarcely  doubt  that  it  lias 
been  formed.  When  wine  is  distilled,  the 
alcohol  readily  separates.  The  distilla- 
tion is  usually  continued  as  long  as  the 
liquid  which  comes  over  is  inflammable- 
The  quantity  obtained,  varies  according 
to  the  wine,  from  a  fourth  to  a  fourteenth 
part  of  the  wine  distilled  The  spirit  thus 
obtained  is  well  known  under  the  name 
of  brandy.  Bullion  has  observed,  that 
when  wine  is  distilled  ntw,  it  yields  more 
alcohol  than  if  it  be  allowed  to  get  old. 
What  remains  after  this  distillation  is  dis- 
tinguished in  France  by  the  name  of  vi- 
nasse  It  consists  of  tartar,  &c.  and  when 
evaporated  to  dryness  and  subjected  to 
combustion,  yields  potash 

3.  Extractive  matter  —  This  matter  ex- 
ists in  all  wines ;  but  its  proportion  dimi- 
nishes according  to  the  age  of  the  wine, 
as  it  gradually  precipitates  to  the  bot- 
tom. 

4.  Every  wine  is  distinguished  by  a 
peculiar  flavour  and  odour,  which  proba- 
bly depends  upon  the  presence  of  a  vola- 
tile oil,  so  small  in  quantity  that  it  can» 
not  be  separated. 

5.  The  colouring  matter  of  wine  is  ori- 
ginally contained  in  the  husk  of  the  grape,, 
and  is  not  dissolved  till  the  alcohol  be 
developed.  This  matter  is  analogous  to 
the  other  colouring  matters  of  plants ;  a 
set  of  bodies  possessed  of  remarkable 
properties,  but  too  little  examined  hither- 
to, to  be  introduced  with  much  advan- 
tage into  a  system  of  chemistry.  This  co- 
louring matter  precipitates  when  the  wine 
is  exposed  to  the  heat  of  the  sun.  It 
sometimes  also  precipitates  in  old  wine, 
and  it  may  be  easily  separated  by  pour- 
ing lime-water  into  wine. 

The  following  table,  containing  the  dif- 
ferent substances  which  Neumann  « ex- 
tracted from  various  wines,  is  worth  pre- 
serving. 


WIN 


WIN 


A  quart  ot 

Highly  rectifi- 
ed Spirit. 

Tl.ick,  oily,  unc- 
tuous, resinous 
matter. 

Gummy  and 
tartarous  mat- 
ter 

Water. 

oz. 

fir 

ur, 

gr. 

oz. 

dr. 

cr. 

oz. 

dr. 

&*• 

lb. 

OZ 

dr. 

gr. 

Aland 

i 
i 

O 

I/O 

9 

no 

c 
o 

OA 

ou 

9 

z 

c 
3 

An 

uo 

Alicant 

3 

6 

00 

D 

A 
U 

2o 

A 

i 
i 

yl  A 

40 

2 

2 

D 

00 

Burgundy 

Z 

n 
Z 

aa 

n 

V/ 

4 

v/vy 

o 

1 

40 

9 

Q 

A 

9A 

Carcassonne 

2 

6 

00 

0 

4 

1 A 

10 

A 

1 
1 

9A 
^0 

z 

8 

4 

30 

Champagne 

2 

5 

20 

n 

0 

a  n 
40 

A 
U 

1 

1 

AA 

2 

o 
o 

o 

00 

French 

6 

n 
0 

00 

A 
U 

D 

A 

u 

1 

JL 

AA 

2 

o 
o 

A 

u 

20 

Frontignac 

3 

0 

00 

3 

4 

00 

A 

5 

o  A 

^0 

2 

4 

6 

30 

Yin  de  Crave 

2 

0 

00 

a 
U 

O 

uo 

A 

yj 

o 
Z 

AA 

2 

9 

0 

00 

Hermitage 

2 

7 

00 

1 

o 
.6 

AA 

A 

1 

/l  A 
4U 

9 

7 

5 

OA 

20 

Madeira 

2 

3 

00 

3 

2 

AA 

o 

z 

A 

u 

AA 
OU 

2 

4 

3 

00 

Malmsey 

4 

0 

00 

4 

3 

AA 

9 

z 

v> 

AA 

2 

1 

2 

00 

Vino  de 

Monte  Pulci-  C 

2 

D 

00 

A 
0 

Q 
O 

AO 

A 

o 

/I  A 

40 

2 

8 

0 

20 

ano  J 

Moselle 

2 

2 

00 

0 

4 

OA 
20 

A 

u 

1 

1 

On 

JO 

2 

9 

0 

10 

Muscadine 

o 

3 

0 

00 

Z 

4 

AA 
00 

A 

An 
00 

2 

5 

4 

00 

Neufschatel 

3 

2 

00 

4 

0 

00 

1 

7 

00 

2 

2 

7 

00 

Palm  Sec 

2 

<-» 
o 

00 

o 

4 

00 

4 

4 

00 

2 

2 

5 

00 

Pontac 

Z 

0 

00 

A 
U 

5 

on 
Z\> 

A 

\J 

2 

nn 
yJU 

9 

0 

40 

Old  Rhenish 

2 

o 

00 

1 

0 

00 

0 

2 

20 

2 

8 

5 

40 

Rhenish 

2 

2 

00 

0 

3 

20 

0 

1 

34 

2 

9 

1 

06 

Salamanca 

3 

0 

00 

J 

4 

00 

2 

0 

00 

2 

3 

4 

00 

Sherry 

3 

0 

00 

6 

0 

00 

2 

2 

00 

2 

0 

6 

00 

Spanish 

1 

2 

00 

o 

4 

00 

9 

4 

00 

1 

10 

6 

00 

Vino  Tinto 

3 

0 

00 

6 

4 

00 

1 

6 

00 

2 

0 

6 

00 

I  okay 

2 

2 

00 

4 

3 

00 

5 

0 

00 

2 

0 

3 

00 

Tyrol  red 

wine  3 
Red  wine 

1 

4 

00 

1 

2 

00 

0 

4 

00 

2 

8 

6 

00 

1 

6 

00 

0 

4 

40 

0 

2 

00 

2 

9 

3 

20 

White 

2 

0 

00 

0 

7 

00 

0 

3 

00 

2 

7 

0 

00 

To  this  head  belong  not  only  common 
wine,  but  all  the  intoxicating  liquors  made 
from  vegetable  juices ;  as  cyder  from  ap- 
ples, perry  from  pears,  currant  wine  &c. 
likewise  the  liquor  made  from  the  juice  of 
the  sugar  cane,  the  sugar  maple,  &c. 

In  the  Archives  of  Useful  Knowledge, 
Vol.  1.  No.  3.  is  a  long  essay  on  the 
cultivation  of  grapes,  and  the  manufac- 
ture  of  wine,  communicated  by  Mr.  Coop- 
er, to  which  we  refer  the  reader.  The 
latest  improvements  of  Mr.  Cooper,  on 
the  manufacture  of  wine,  we  deem  of  im- 
portance, and  accordingly  give  them  in 
his  own  language. 

"  I  gather  the  grapes  when  fully  ripe 
and  dry,  separate  the  rotten  or  unripe 
from  the  others,  and  press  for  distillation 
if  the  quantity  is  worth  attending  to ;  1 
then  open  the  cider-mill,  so  as  not  to 
mash  the  stems  or  seed  of  the  grapes  ; 
then  run  them  through,  put  the  pummice 
or  mashed  grapes,  on  some  clean  long 
straw,  previously  made  damp,  and  laid 
•n  the  cider-press  floor,  lap  it  in  the 


straw,  press  it  well,  then  take  off  the  pum- 
mice and  add  some  water,  or  I  believe 
sweet  unfermented  cider  would  be  better, 
and  answer  in  lieu  of  sugar.  After  it  has 
soaked  awhile,  (but  do  not  let  it  ferment 
in  the  pummice,)  press  as  before,  put  all 
together,  and  add  sugar  until  it  is  an 
agreeable  sweet.  1  have  found  a  pound  to 
a  gallon,  sufficient  lor  the  sourest  grapes, 
and  white  Havanna  sugar  for  the  best , 
but  sweet  grapes  make  the  best  wine, 
without  any  sugar. 

"  1  have  heretofore  recommended  put- 
ting the  sugar  in,  after  fermentation,  but 
on  experience  find  it  not  to  keep  as  well, 
and  am  now  convinced  that  all  the  sac- 
charine matter  for  making  wine,  should 
be  incorporated  before  fermentation. — 
Previously  to  fermentation,  I  place  the 
casks  three  or  four  feet  from  the  floor  ; 
as  the  filth  works  out,  fill  it  up  two  or 
more  times  a  day,  till  it  emits  a  clear 
froth,  then  check  the  fermentation  gra- 
dually, by  putting  the  bung  on  slack,  and 
tighten  it,  as  the  fermentation  abates.— 


WIN 


WIN 


When  the  fretting  has  nearly  ceased,  rack 
it  off:  for  which  purpose  I  have  an  in- 
strument nearly  in  the  shape  of  a  wooden 
shovel,  with  a  gutter  in  the  upper  side  of 
the  handle;  place  it  so  as  to  prevent 
waste,  and  let  it  dribble  into  a  tub  slowly , 
which  gives  the  fretting  quality  an  op- 
portunity to  evaporate,  tranquillizes  the 
liquor,  and  hastens  the  maturity.  When 
the  cask  is  empty,  rinse  it  with  fine  gra- 
vel, to  scour  off"  the  yeast  that  adheres  to 
it  from  fermentation,  then  for  each  gallon 
of  wine  put  in  one  pint  of  good  high  proof 
French,or  apple  brandy,fill  the  ca^k  about 
one-third,  then  burn  a  sulphur  match  in 
it ;  when  the  match  is  burnt  out,  siop  the 
bung-hole,  and  shake  it  to  incorporate 
the  smoke  and  liquor  ;  fill  the  cask,  and 
place  it  as  before,  and  in  about  a  month 
rack  it  again  as  directed  above ;  the  gra- 
vel is  unnecessary  after  the  first  racking. 
If  the  match  should  not  burn  well  the 
first  racking,  repeat  it ;  and  if  it  don't 
taste  strong  enough  to  stand  hot  weather, 
add  more  brandy.  I  have  racked  my 
wine  three  or  four  times  in  a  year,  and 
find  it  to  help  its  ripening;  have  frequent- 
ly bad  casks  on  tap  for  years,  and  always 
found  the  liquor  to  improve  to  the  last 
drawing. 

"  Being  fully  of  opinion  that  our  com 
mon  wine  grapes,  are  capable  of  produc- 
ing wine  as  good  and  as  palatable,  (pre- 
judice aside)  and  far  more  wholesome, 
than  the  wine  generally  imported  at  so 
great  an  expense  :  and  a  supply  of  that 
article  being  very  uncertain,  I  am  induc- 
ed to  urge  the  making  wine  of  all  the 
native  grapes  that  can  be  procured  ;  and 
in  collecting  them,  to  notice  the  vines  that 
produce  grapes  of  the  best  quality,  and 
which  are  the  most  productive^  as  this 
will  en;. hie  persons  to  select  the  best  vine, 
to  cultivate  and  propagate  from.  This 
ought  to  be  particularly  attended  to,  as 
there  are  many  vines  which  produce  good 
grapes,  but  few  in  quantity,  and  others 
very  productive  but  of  bad  quality  :  and 
I  believe  full  half  the  number,  that  come 
from  the  seeds  are  males,  and  will  never 
bear  fruit.  The  sex  is  easily  distinguish- 
ed when  in  bloom,  by  the  females  show- 
ing the  fruit  in  the  heart  of  the  blossom, 
as  soqn  as  open,  and  the  male  presenting 
nothing  of  that  kind. 

"  As  the  native  grape-vine  will  not  grow 
well  from  cuttings,  the  best  way  I  know 
of,  to  propagate  them,  is  by  removing  the 
vine,  or  laying  branches  in  the  earth  to 
take  root  for  a  year  or  more,  and  when 
rooted  remove  them,  or  plant  the  seeds 
from  the  best  kinds  ;  and  when  in  bloom 
dig  up  the  males.  If  well  cultivated,  they 
will  blow  in  three  or  four  years,  but  will 


produce  different  kinds,  the  same  as  ap- 
ples ;  and  I  have  had  some  from  the  seeds 
superior  to  the  parent.'* 

We  shall  now  mention  the  manner  of 
making  one  or  two  other  wines,  as 

Cider  Wine. 
This  is  made  by  evaporatng  the  fresh 
apple  juice,  in  a  brewers  copper  or  other 
convenient  vessel ;  and  when  it  is  half 
consumed,  the  remainder  is  to  be  convey- 
ed to  a  wooden  cooler,  and  then  put  into 
casks,  and  fermented  with  yeast  in  the 
usual  way. 

Currant  Wine. 

To  14  lbs.  of  currants  put  three  gallons 
of  water  ;  break  them  ;  and  after  stand- 
ing  a  day  or  two,  express  them.  To  the 
juice  add  14  lbs.  of  sugar,  and  barrel  it; 
in  14  days  it  will  have  fermented.  After 
which  bung  the  barrel,  previously  adding, 
one  quart  of  brandy,  to  every  10  gallons. 

All  those  nutritive,  vegetable,  and  ani- 
mal matters,  which  contain  sugar  ready 
formed,  are  susceptible  of  the  spirituous- 
fermentation.  Thus  wine  may  be  made 
of  all  the  juices  of  plants,  the  sap  of  trees, 
the  infusions  and  decoctions  of  farinace- 
ous vegetables,  the  milk  of  fru&ivorous 
animals  ;  and  lastly,  it  may  be  made  of 
all  ripe  succulent  fruits  ;  but  all  these 
substances  are  not  equally  proper  to  be 
changed,  into  a  good  and  generous  wine 

As  the  production  of  alcohol  is  the  re- 
sult of  the  spirituous  fermentation,  that 
wine  may  be  considered  as  essentially  the 
best,  which  contains  most  alcohol.  But 
of  all  substances,  susceptible  of  the  spiri- 
tuous fermentation,  none  is  capable  of 
being  converted  into  so  good  a  wine,  as 
the  juice  of  the  grapes  of  France,  or  of 
other  countries, that  are  in  the  same  lati- 
tude, or  in  the  same  temperature.  The 
grapes  of  hotter  countries,  and  even  those 
of  the  southern  provinces  of  France,  do 
indeed  furnish  wines,  that  have  a  more, 
agreeable,  that  is,  more  of  a  saccharine 
taste  ;  but  these  wines,  though  they  are 
sufficiently  strong,  are  not  so  spirituous 
as  those  of  the  provinces  near  the  middle 
of  France :  at  least,  from  these  latter 
wines,  the  best  vinegar  and  brandy  are 
made.  As  an  example,  therefore,  of  spi- 
rituous fermentation  in  general,  we  shall 
describe  the  method  of  making  wine  from 
the  juice  of  the  grapes  of  France. 

The  juice,  when  newly  expressed,  and 
before  it  has  begun  to  ferment,  is  called 
must,  and  in  common  language  sweet 
wine.  It  is  turbid,  has  an  agreeable  and 
very  saccharine  taste.  It  is  very  laxative  ; 
and  when  drunk  too  freely,  or  by  persons 
disposed  to  diarrhoeas,  it  is  apt  to  occa- 
sion these  disorders.   Its  consistence  is 


WIN 


!  somewhat  less  fluid  than  that  of  water, 
and  it  becomes  of  a  pitchy  thickness, 
when  dried. 

When  the  must  is  pressed  from  the 
grapes,  and  put  into  a  vessel  and  place, 
in  a  temperature  between  55  and  60° 
Fahr.  very  sensible  effects  are  produced 
in  it,  in  a  shorter  or  longer  time,  accord- 
ing to  the  nature  of  the  liquor,  and  the 
exposure  of  the  place.  It  then  swells, 
anil  is  so  rarefied,  that  it  frequently  over- 
flows the  vessel  containing  it,  if  this  be 
nearly  full.  An  intestine  motion  is  ex- 
cited among  its  parts,  accompanied  with 
a  small  hissing  noise,  and  evident  ebulli- 
tion. The  bubbles  rise  to  the  surface, 
and  at  the  same  time  \s  disengaged  a 
quantity  of  carbonic  acid,  of  much  pu- 
rity. 

The  skins,  stones,  and  other  grosser 
matters  of  the  grapes,  are  buoyed  up  by 
the  particles  of  disengaged  air,  that  ad- 
here to  their  surface,  are  variously  agi- 
tated, and  are  raised  in  form  of  a  scum  or 
soft  and  spongy  crust,  that  covers  the 
whole  liquor.  During  the  fermentation 
this  crust  is  frequently  raised,  and  broken 
by  the  air  disengaged  from  the  liquor 
which  forces  its  way  through  it ;  after- 
wards the  crust  subsides,  and  becomes 
entire  as  before. 

These  effects  continue  while  the  fer- 
mentation is  brisk,  and  at  last  gradually 
cease  :  then  the  crust  being  no  longer 
supported,  falls  in  pieces  to  the  bottom  of 
the  liquor.  At  this  time,  if  we  would 
have  a  strong  and  generous  wine,  all  sen- 
sible fermentation  must  be  stopped.  This 
is  done  by  putting  the  wine  into  close  ves- 
sels, and  carrying  these  into  a  cellar  or 
other  cool  place. 

After  this  first  operation,  an  interval 
of  repose  takes  place,  as  is  indicated  by 
the  cessation  of  the  sensible  effects,  of  the 
spirituous  fermentation  ;  3nd  thus  ena- 
bles us  to  preserve  a  liquor  no  less  agree- 
able in  its  taste,  than  useful  for  its  reviv- 
ing and  nutritive  qualities  when  drunk 
moderately. 

If  we  examine  the  wine  produced  by 
this  first  fermentation,  we  shall  find,  that 
it  differs  entirely  and  essentially  from  the 
juice  of  grapes  before  fermentation.  Its 
sweet  and  saccharine  taste,  is  changed 
into  one  that  is  very  different,  though  still 
agreeable,  and  somewhat  spirituous  and 
piquant.  It  has  not  the  laxative  quality 
of  must,  but  affects  the  head,  and  occa- 
sions, as  is  well  known,  drunkenness. — 
Lastly,  if  it  be  distilled,  it  yields,  instead 
of  the  insipid  water  obtained  from  must, 
by  distillation  with  the  heat  of  boiling 
water,  a  volatile,  spirituous,  and  inflam- 
mable liquor,  c,alled  spirit  of  wine,  or  al- 


cohol. This  spirit  is  consequently  a  new 
being,  produced  by  the  kind  of  fermen- 
tation, called  the  vinous  or  spirituous.  See 
Alcohol. 

When  any  liquor  undergoes  the  spiri- 
tuous fermentation,  all  its  parts  seem  not 
to  ferment  at  the  same  time,  otherwise 
the  fermentation  would  probably  be  very 
quickly  completed,  and  the  appearance 
would  be  much  more  striking  :  hence,  in  a 
liquor  much  disposed  to  fermentation,this 
motion  is  more  quick  and  simultaneous, 
than  in  any  other  liquor.  Experience  has 
shown,  that  a  wine,  the  fermentation  of 
which  is  very  slow  and  tedious,  is  never 
good  or  very  spirituous  ;  and  therefore* 
when  the  weather  is  too  cold,  the  fermen- 
tation is  usually  accelerated,  by  heating 
the  place,  in  which  the  wine  is  made.  A 
proposal  has  been  made  by  a  person  very 
intelligent  in  economical  affairs,  to  ap- 
ply a  greater,  than  the  usual  heat,  to  ac- 
celerate the  fermentation  of  the  wine,  in 
those  years,  in  which  grapes  have  not 
been  sufficiently  ripened,  and  when  the 
juice  is  not  sufficiently  disposed  to  fer- 
mentation. 

A  too  hasty  and  violent  fermentation  is 
perhaps  also  hurtful,  from  the  dissipa- 
tion and  loss  of  some  of  the  spirit :  but  of 
this  we  are  not  certain.  However,  we 
may  distinguish  in  the  ordinary  method r 
of  making  wines  of  grapes,  two  periods 
in  the  fermentation,  the  first  of  which 
lasts  during  the  appearance  of  the  sensi- 
ble eflects  above-mentioned,  in  which  the 
greatest  number  of  fermentable  particles 
ferment.  After  this  first  effort  of  fermen  • 
tation,  these  eflects  sensibly  diminish,  and 
ought  to  be  stopped  for  reasons,  hereaf- 
ter to  be  mentioned.  The  fermentative 
motion  of  the  liquors  then  ceases.  The 
heterogenous-  parts,  that  were  suspended 
in  the  wine  by  this  motion,  and  render  it 
muddy,  are  separated,  and  form  a  sedi- 
ment called  the  lees;  after  which  the 
wine  becomes  clear :  but  though  the  ope- 
ration is  then  considered  as  finished,  and 
the  fermentation  apparently  ceases,  it 
does  not  really  cease  :  and  it  ought  to  be 
continued  in  some  degree,  if  we  would 
have  good  wine. 

In  this  new  wine,  a  part  of  the  liquor 
probably  remains,  that  has  not  fermented, 
and  which  afterwards  ferments,  but  so 
very  slowly,  that  none  of  the  sensible  ef- 
fects produced  in  the  first  fermentation., 
are  here  perceived.  The  fermentation 
therefore  still  continues  in  the  wine,  dur 
ing  a  longer  or  shorter  time,  although  in 
an  imperceptible  manner;  and  this  is  the 
second  period  of  the  spirituous  fermenta- 
tion, which  may  be  called  the  impercep 
tible  fermentation.   "We  may  easily  per 


WIN 

tcive,  that  the  effect  of  this  imperceptible 
fermentation  is  the  gradual  increase  of  the 
quantity  of  alcohol.  It  has  also  another 
effect  no  less  advantageous,  namely,  the 
separation  of  the  acid  salt  called  tartar 
from  the  wine.  This  matter  is  therefore 
a  second  sediment,  that  is  formed  in  the 
wine,  and  adheres  to  the  sides  of  the  con- 
taining vessels.  As  the  taste  of  tartar  is 
harsh  and  disagreeable,  it  is  evident,  that 
the  wine,  which  by  means  of  the  sensible 
fermentation  has  acquired  more  alcohol, 
and  has  disengaged  itself  of  the  greater 
part  of  its  tartar,  ought  to  be  much  bet- 
ter and  more  agreeable  ;  and  for  this  rea- 
son chiefly,  old  wine  is  universally  prefer- 
able to  new  wine. 

But  insensible  fermentation  can  only 
ripen  and  meliorate  the  wine,  if  the  sen* 
sible  fermentation  have  regularly  pro- 
ceeded,  and  been  stopped  in  due  time. 
We  know  certainly,  that  if  a  sufficient 
time  have  not  been  allowed  for  the  first 
period  of  the  fermentation,  the  unferment- 
ed  matter  that  remains,  being  in  too  large 
a  quantity,  will  then  ferment  in  the  bot- 
tles, or  close  vessels  in  which  the  wine  is 
put,  and  will  occasion  effects  so  much 
more  sensible,  as  the  first  fermentation 
shall  have  been  sooner  interrupted:  hence 
these  wines  are  always  turbid,  emit  bub- 
bles, and  sometimes  break  the  bottles, 
from  the  large  quantity  of  air  disengaged 
during  the  fermentation. 

We  have  an  instance  of  these  effects  in 
the  wine  of  Champagne,  and  in  others  of 
the  same  kind.  The  sensible  fermenta- 
tion of  these  wines  is  interrupted,  or  ra- 
ther suppressed,  that  they  may  have  this 
sparkling  quality.  It  is  well  known,  that 
these  wines,  make  the  corks  fly  out  of  the 
bottles,  that  they  sparkle  and  froth  when 
they  are  poured  into  glasses,  and  lastly, 
that  they  have  a  taste  much  more  lively, 
and  more  piquant  than  wines  that  do  not 
sparkle  ;  but  this  sparkling  quality,  and 
all  the  effects  depending  on  it,  are  only 
caused  by  a  considerable  quantity  of  car- 
bonic acid  gas,  which  is  disengaged  dur- 
ing the  confined  fermentation,  that  the 
wine  has  undergone  in  close  vessels.  This 
air  not  having  ail  opportunity  of  escaping, 
and  of  being  dissipated  as  fast  as  it  is  dis- 
engaged, and  being  interposed  betwixt 
all  the  parts  of  the  wine, combines  in  some 
measure  witli  them,  and  adheres  in  the 
same  manner,  as  it  does  to  certain  mine- 
ral waters,  in  which  it  produces  nearly 
ihe  same  effects.  When  tin's  air  is  entire- 
ly disengaged  from  these  wines,  they  no 
longer  sparkle,  they  lose  their  piquancy 
of  taste,  become  mild,  and  even  almost 
Tusipid. 


WIN 

Such  are  the  qualities  that  wine  acquires 
in  time,  when  its  fermentation  has  not 
continued  sufficiently  long.  These  qua- 
lities are  given  purposely,  to  certain  kinds 
of  wine,  to  indulge  taste  or  caprice  -, 
but  such  wines  are  supposed  to  be  unfit 
for  daily  use  Wines  for  daily  use  ought  to 
have  undergone  so  completely  the  sensi- 
ble fermentation,  that  the  succeeding  fer- 
mentation shall  be  insensible,  or  at  least 
exceedingly  little  perceived.  Wine,  in 
which  the  first  fermentation  has  been  too 
far  advanced,  is  liable  to  worse  inconve- 
niences,  than  that  in  which  the  first  fer- 
mentation has  been  too  quickly  suppress- 
ed ;  for  every  fermentable  liquor  is  from 
its  nature  in  a  continual  intestine  motion, 
more  or  less  strong,  according  to  circum- 
stances, from  the  first  instant  of  the  spiri- 
tuous fermentation,  till  it  is  completely 
putrefied  :  hence  from  the  time  of  the 
completion  of  the  spirituous  fermentation, 
or  even  before,  the  wine  begins  to  under- 
go the  acid,  or  acetous  fermentation.  This 
acid  fermentation  is  very  slow  and  insen- 
sible, when  the  wine  is  included  in  very 
close  vessels,  and  in  a  cool  place  ;  but  it 
gradually  advances,  so  that  in  a  certain 
time  the  wine,  instead  of  being  improved, 
becomes  at  last  sour.  This  evil  cannot 
be  remedied ;  because  the  fermentation 
may  advance,  but  cannot  be  reverted. 

Wine-merchants,  therefore,  when  their 
wines  become  sour,  can  only  conceal  or 
absorb  this  acidity  by  certain  substances, 
as  by  alkalies  and  absorbent  earths.  But 
these  substances  give  to  wine  a  dark 
greenish  colour,  and  a  taste  which,  though 
not  acid,  is  somewhat  disagreeable.  Be- 
sides, calcareous  earths  accelerates  con- 
siderably,  the  total  destruction  and  putre- 
faction of  the  wine.  Oxyds  of  lead,  hav- 
ing the  property  of  forming  with  the  acid 
of  vinegar,  a  salt  of  an  agreeable  saccha- 
rine taste,  which  does  not  alter  the  colour 
of  the  wine,  and  which  besides  has  the 
advantage  of  stopping  fermentation  and 
putrefaction,  might  be  very  well  employ- 
ed to  remedy  the  acidity  of  wine,  if  lead 
and  all  its  preparations  were  not  pernici- 
ous to  health,  as  they  occasion  most  ter- 
rible cholics,  and  even  death,  when  taken 
internally.  We  cannot  believe  that  any 
wine-merchant,  knowing  the  evil  conse- 
quences of  lead,  would  for  the  sake  of 
gain,  employ  it  for  the  purpose  mention- 
ed ;  but  if  there  be  any  such  persons,  they 
must  be  considered  as  the  poisoners  and 
murderers  of  the  public.  At  Alicant,  where 
very  sweet  wines  are  made,  it  is  the  prac- 
tice, to  mix  a  little  lime  with  the  grapes, 
before  they  are  pressed.  This,  however, 
can  only  neutralize  the  acid  already  exist- 
ing in  the  grape 


WIN 


WIN 


If  wine  contain  litharge,  or  any  other 
oxide  of  lead,  it  may  be  discovered  by 
evaporating  some  pints  of  it  to  dryness, 
and  melting  the  residuum  in  a  crucible, 
at  the  bottom  of  which  a  small  button  of 
lead  may  be  found  after  the  fusion ;  but 
an  easier  and  more  expeditious  proof  is 
by  pouring  into  the  wine  some  liquid  sul- 
phuret.  If  the  precipitate  occasioned  by 
this  addition  of  the  sulphuret  be  white, 
or  only  coloured  by  the  wine,  we  may 
know,  that  no  lead  is  contained  in  it ;  but 
if  the  precipitate  be  dark  coloured,  brown 
or  blackish,  we  may  conclude,  that  it  con- 
tains ead  or  iron.  The  test  by  Hahne- 
mann, (which  see  under  the  head  of 
Tests)  however,  precipitates  only  lead 
and  copper,  black,  arsenic  of  an  orange 
colour,  and  doe^  not  throw  down  iron. 

Wine,  which  might  have  been  long  pre- 
served in  a  cool  place,  very  quickly  be- 
comes sour  when  placed  in  a  bad  cellar ; 
and  even  as  the  best  cellars  have  during 
winter  a  degree  of  heat  much  above 
that  of  the  atmosphere,  it  would  be  very 
proper,  when  wine  disposed  to  become 
sour  is  to  be  preserved,  to  bring  it  from 
the  cellar  in  the  beginning  of  winter,  and 
leave  it  exposed  to  the  air  during  all  that 
season. 

Wine  is  also  liable  to  various  other 
changes;  such  as  to  become  ropy  and 
mucilaginous,  by  the  continuance  of  the 
fermentative  motion. 

Wine,  and  the  matters  produced  from 
wine,  as  brandy,  spirit  of  wine,  vinegar, 
lees  of  wine,  tartar,  are  greatly  and  exten- 
sively useful.  The  lees  of  wine  are  em- 
ployed in  the  manufacture  of  hats.  These 
lees,  and  also  tartar,  by  incineration,  yield 
a  larger  quantity  than  any  other  vegeta- 
ble matter  of  pure  fixed  alkali. 

Wine  has  been  preferred  at  all  times 
and  in  all  countries  to  every  other  ali- 
mentary liquor.  We  may  say  in  general, 
that  it  is  good  and  salutary,  when  taken 
in  small  quantities,  and  that  it  is  perni- 
cious when  drunk  habitually  and  in  too 
large  quantities.  Wine  becomes  then  a 
true  slow  poison,  which  is  so  much  more 
dangerous,  as  it  is  more  agreeable.  15ut 
if  we  observe  more  particularly  the  ef- 
fects of  wine,  we  shall  perceive  very  great 
differences  depending  on  different  con- 
stitutions. Some  persons  drink  habitual- 
ly large  quantities  of  pure  wine,  without 
any  sensible  inconvenience  or  disease,  or 
apparently  shortening  their  lives  ;  but,  on 
the  contrary,  many  others  do  also  entire- 
ly destroy  their  health  and  shorten  their 
lives  by  an  habitual  use  of  wine,  even  in 
small  quantity,  and  mixed  with  water — 
although  it  is  always  more  safe  and  pru- 


dent for  every  person  to  drink  little  of  it 
habitually,  and  this  moderation  is  more  in- 
dispensably necessary  to  those  whose  con- 
stitutions wine  does  not  suit. 

As  the  diseases  consequent  upon  the 
too  free  use  of  wine,  come  on  gradually 
and  insensibly,  sometimes  even  during 
many  years,  several  persons,  especially 
men  otherwise  very  sober  and  attentive 
to  health,  are  every  day  deceived  in  this 
article,  drinking  more  wine  than  is  suita- 
ble to  their  constitution,  and  gradually 
ruiningtheir  health,  without  knowing  the 
cause.  It  is  therefore  a  matter  of  impor- 
tance, to  show  the  signs  by  which  wine 
may  be  known  to  be  hurtful. 

We  may  know  that  wine  does  not  suit 
a  person,  when,  after  drinking  moderately 
of  it,  his  breath  acquires  a  vinous  smell ; 
when  it  occasions  sour  belchings  and 
slight  pains  in  the  head  ;  and  when,  after 
drinking  it  more  copiously  than  usual,  it 
produces  stupefaction,  nausea  and  drunk- 
enness, especially  when  this  drunkenness 
is  of  the  morose,  peevish,  quarrelsome, 
and  irascible  kind.  Unhappy  is  that  per- 
son who  suffers  these  effects  from  wine, 
and  notwithstanding  persists  in  the  habit- 
ual use  of  it  These  imprudent  persons 
never  fail  of  coming  to  a  miserable  death, 
preceded  by  languor,  and  premature ; 
their  common  age  being  about  fifty  years, 
or  a  little  more.  The  diseases  to  which 
they  are  most  subject  are  obstructions  in 
the  liver,  in  the  mesenteric  glands,  and  in 
other  abdominal  viscera,  which  are  almost 
always  succeeded  by  an  incurable  dropsy. 
Those  who  digest  wine  well  do  not  suffer, 
or  much  less  sensibly,  the  above-men- 
tioned effects  of  drinking  it-  Their  drunk- 
enness is  accompanied  w  ith  vivacity  and 
joy.  Such  persons  seldom  die  of  the  ob- 
structions and  dropsy  above-mentioned  ; 
but  wine  is  nevertheless  so  much  more 
dangerous  to  them,  that,  as  they  suffer 
none  of  the  disagreeable  effects,  they  are 
more  liable  to  contract  the  habit  of  drink 
ing  too  much.  Drinkers  of  this  class  ge- 
nerally live  somewhat  longer  than  the 
former;  but  their  constitution  changes 
before  sixty  years  of  age;  and  the 
inheritance  of  their  old  age  is  either  a. 
severe  gout  or  palsy,  stupidity,  imbeci- 
lity, or  an  accumulation  of  these  dis- 
eases. 

We  need  not  mention  that  the  too  fre- 
quent use  of  brandy,  liqueurs,  as  they 
are  called,  or  cordials,  and  other  spiritu- 
ous liquors,  is  still  more  pernicious  and 
fatal  than  that  of  wine. 

Wine  is  used  in  medicine  as  a  vehicle 
in  the  composition  of  many  internal  and 
external  remedies.  As  wine  is  composed 
of  alcohol,  water,  extractive  saponaceous 


WIN 


WIN 


matter,  and  acid  of  tartar,  it  may  be  very 
usefully  employed  for  the  extraction  of  al- 
most all  the  proximate  principles,  and 
consequently  of  the  medicinal  parts,  of 
vegetables.  Many  extracts  are  made  with 
Wine,  which  may  be  considered  as  being 
more  complete  than  those  made  with  wa- 
ter; but  physicians  who  prescribe  these 
extracts,  ought  to  remember,  that,  beside 
the  principles  of  the  vegetables,  they  also 
contain  the  extractive  part  of  the  wine, 
that  is,  all  the  principles  of  wine,  except- 
ing the  alcohol,  which  is  too  volatile  to 
remain  in  an  extract. 

As  wine  when  good  may  be  preserved 
during  a  long  time,  several  medicinal 
wines  prescribed  in  dispensatories,  are 
kept  in  the  shops  of  apothecaries.  In 
many  cases,  as  in  several  chronical  dis- 
eases, where  tonic,  cordial,  foitifyiug,and 
exciting  remedies  are  indicated,  physi- 
cians prefer  the  use  of  wine  to  water,  as  a 
vehicle  for  the  infusion  of  purgative,  open- 
ing, and  other  medicinal  substances.  See 
Alcohol. 

In  addition  to  the  remarks  already  made, 
the  following  miscellaneous  observations 
we  take  from  the  memoir  of  C.  Chaptal, 
entitled  "  A  Treatise  on  the  cultivation  of 
the  Vine,  and  the  method  of  making 
Wines." 

The  faults  of  fermentation  arise  natu- 
rally from  the  quality  of  the  grapes, 
which  are  the  subject  of  it ;  and  from  the 
temperature  of  the  air,  which  may  be 
considered  as  a  very  powerful  auxili- 
ary. 

Grapes  may  not  contain  a  sufficiency 
of  sugar  to  produce  a  sufficient  forma- 
tion of  alcohol ;  and  this  vice  may  be 
owing  to  the  grapes  not  having  attained 
to  maturity,  or  to  the  sugar  being  diluted 
in  too  considerable  a  quantity  of  water  ; 
or  because  sugar,  by  the  nature  of  the 
climate,  cannot  sufficiently  develope  it- 
self In  all  cases  there  are  two  ways  of 
correcting  the  vice  which  exists  in  the 
nature  of  the  grapes  :  the  first  consists  in 
conveying  into  the  must  that  principle 
which  it  wants :  a  proper  addition  of  su- 
gar presents  to  fermentation  the  materials 
necessary  for  the  formation  of  alcohol,  and 
the  deficiency  of  nature  is  supplied  by 
art.  The  antients,  it  appears,  were  ac- 
quainted with  this  process,  since  they 
mixed  honey  with  the  must  which  they 
caused  to  ferment. 

Experiments  seem  to  prove,  beyond  all 
doubt,  that  the  best  method  of  remedying  | 
the  want  of  maturity  in  grapes,  is  to  fol-  > 
low  the  process  indicated  by  nature ;  that  i 
is  to  say,  to  introduce  into  the  must  that ) 
quantity  of  saccharine  principle  necessary, ! 
which  it  could  not  give  them,    This  me- 1 


thod  is  the  more  practicable,  as  not  onry 
sugar,  but  also  honey,  molasses,  and  eve- 
ry other  saccharine  matter  of  an  inferior 
price,  can  produce  the  same  effect,  pro- 
vided they  have  no  disagreeable  acetous 
taste  which  cannot  be  destroyed  by 
good  fermentation. 

Bullion,  caused  the  juice  of  grapes,  ta- 
ken from  his  park  at  Bellegames,  to  fer- 
ment by  adding  from  15  to  20  pounds  of 
sugar  per  muid  (280  quarts).  The  wine 
they  produced  was  of  a  good  quality. 

llozier,  long  ago,  proposed  to  facilitate 
the  fermentation  oi'must,  and  ameliorate 
wines  by  the  addition  of  honey,  in  the  pro- 
portion of  a  pound,  to  two  hundred  of 
must. 

It  is  possible  also  to  correct  the  quali- 
ty of  the  grapes  by  other  means,  which 
are  daily  practised.  A  portion  of  the  must 
is  boiled  in  a  kettle ;  it  is  concentrated  to 
one-half,  and  then  poured  into  a  vat.  By 
this  method  the  aqueous  portion  is  in  part 
dissipated,  and  the  portion  of  sugar  being 
then  less  diluted,  the  fermentation  pro 
ceeds  with  more  regularity,  and  the  pro- 
duce is  more  generous.  This  process,  al- 
most always  useful  in  the  north,  cannot 
be  employed  in  the  south,  but  when  the 
season  has  been  rainy,  or  when  the  grapes 
have  not  been  sufficiently  ripe. 

The  same  end  may  be  attained  by  dry- 
ing the  grapes  in  the  sun,  or  exposing 
them  for  the  same  purpose,  in  stoves, 
as  is  practised  in  some  wine  countries. 

It  is  perhaps  for  the  same  reason,  al- 
ways with  a  view  to  absorb  the  moisture, 
that  plaster  is  sometimes  put  into  the 
vat,  as  was  practised  by  the  ancients. 

It  sometimes  happens  that  the  must  is 
both  too  thick,  and  too  saccharine.  In  that 
case  the  fermentation  is  always  slow  and 
imperfect :  the  wines  are  sweet,  luscious, 
and  thick ;  and  it  is  not  till  after  remain- 
ing a  long  time  in  the  bottles,  that  it  be- 
comes clear,  loses  its  disagreeable  thick- 
ness, and  only  exhibits  good  qualities.  The 
greater  part  of  the  white  Spanish  wines 
are  in  this  situation.  This  quality  of  wine 
has  however  its  partisans,  and  there  are 
some  countries  where  the  must  is  con- 
centrated for  that  purpose  ;  in  others  the 
grapes  are  dried  in  the  sun  or  in  stoves 
till  they  are  reduced  almost  to  the  con- 
sistence of  an  extract. 

It  would  be  easy  in  all  cases  to  excite 
fermentation,  either  by  diluting  the  must, 
when  too  thick,  with  water,  or  by  agita- 
ting the  vintage  in  proportion  as  it  fer 
ments  :  but  all  this  must  be  subordinate 
to  the  end  proposed  to  be  obtained,  and 
the  intelligent  vintner  will  vary  his 
processes  according  to  the  effect  which  he 
intends  to  produce. 


WIN 


WIN 


It  must  never  be  forgotten,  that  the  fer- 
mentation ought  to  be  managed  accord- 
ing to  the  nature  of  the  grapes,  and  agree- 
ably to  the  quality  of  the  wine  that  may  be 
required. 

In  cold  countries,  where  the  grapes  are 
very  aqueous,  and  little  saccharine,  they 
ferment  with  difficulty.  Fermentation  in 
that  case  may  be  excited  by  two  or  three 
principal  means  : 

1st,  By  the  help  of  a  funnel  of  tin  plate 
with  a  very  wide  tube,  which  descends  to 
within  four  inehes  of  the  bottom  of 
the  vat,  and  through  which  boiling  must 
is  introduced  into  it  Two  pailfuls  may  be 
used  for  300  bottles  of  must.  This  pro- 
cess, proposed  by  Maupin,  has  produced 
good  effects. 

2d,  By  shaking  the  vintage  from  time  to 
lime.  This  motion  is  attended  with  this 
advantage,  that  it  renews  the  fermenta- 
tion when  it  has  ceased  or  become  weak, 
and  causes  it  to  be  uniform  throughout 
the  mass. 

3d,  By  laying  a  covering  not  only 
over  the  vintage,  but  round  about  the 
vat. 

4th,  By  heating  the  atmosphere  of  the 
place  in  which  the  vat  stands. 

The  antients  mixed  aromatic  substan- 
ces with  the  vintage  in  a  state  of  fermen- 
tation, in  order  to  give  their  wines  pecu- 
liar qualities.  We  are  told  by  Pliny,  that 
it  was  usual  in  Italy  to  sprinkle  pitch,  and 
resin  over  the  vintage,  ut  odor  vino  contin- 
geret  et  saporis  acumen.  In  all  the  works 
of  that  period,  we  find  numerous  recipes 
for  perfuming  wines  ;  but  these  different 
processes  are  no  longer  used.  I  am,  how- 
ever, inclined  to  think  that  they  were  of 
great  benefit.  This  very  important  part 
of  oinology,  deserves  the  particular  at- 
tention of  the  agriculturist.  When  we 
consider  the  custom  followed  in  some 
countries,  of  perfuming  the  wines  with 
rasberries,  the  dried  flowers  of  the  vine, 
&c  we  may  even  presage  the  happiest  ef- 
fects from  it. 

The  method  of  taking  the  Wine  from  the 
Vats,  and  the  proper  period  for  that  pur- 
pose. 

At  all  times  agriculturists  have  consi- 
dered it  as  a  matter  of  great  importance, 
to  be  able,  by  unerring  signs,  to  discover 
the  most  favourable  period  for  taking  the 
wine  from  the  vats  ;  but  here,  as  in  other 
things,  they  have  fallen  into  the  very  great 
inconvenience  of  general  methods.  This 
period  ought  to  vary  according  to  the 
climate,  the  season,  and  the  nature  of  the 
wine  proposed  to  be  obtained,  and  of 
other  circumstances,  which  must  always 
be  kept,  in  view. 
VOL*  II. 


According  to  principles  deduced  from 
theory,  we  may  draw  the  following  con- 

sequences. 

1st,  The  must  ought  to  remain  in  the 
vats  the  less  time,  according  as  it  is  less 
saccharine.  Light  wines,  called  in  Bur- 
gundy, wis  de  primtur,  cannot  bear  the 
vat  above  from  six  to  twelve  hours. 

2d,  The  must  ought  to  remain  the  less 
time  in  the  vats,  according  as  it  is  propo- 
sed to  retain  the  acid  gas,  and  to  form 
brisk  wines.  In  that  case,  it  is  thought 
sufficient  to  tread  the  grapes,  and  to  put 
the  juice  into  the  casks  after  it  has  been 
left  in  the  vat  twenty-four  hours,  and 
sometimes  without  having  been  in  the  vat 
at  all.  In  this  case,  the  fermentation  on 
the  one  hand,  is  less  tumultous  ;  and,  on 
the  other,  the  gas  can  with  less  ease  be 
volatilized,  which  contributes  to  retain 
that  highly  volatile  substance,  and  to 
make  it  one  of  the  principles  of  the  li- 
quor. 

3d,  Must  ought  to  be  left  in  the  vats 
less  time,  according  as  it  is  proposed  to 
obtain  wine  less  coloured.  This  condi- 
tion is  of  great  importance  in  regard  to 
brisk  wines,  one  of  the  most  valuable  qua- 
lities of  which  is  their  want  of  colour. 

4th,  Must  ought  to  remain  in  the  vats 
less  time,  according  as  the  temperature 
is  warmer,  and  the  mass  more  volumi- 
nous, &c.  In  that  case,  the  briskness  of 
%the  fermentation  makes  up  for  its  short- 
ness of  duration. 

5th,  The  must  ought  to  remain  in  the 
vats  less  time,  according  as  it  is  propo- 
sed to  obtain  wine  of  a  more  agreeable 
flavour. 

6th,  The  fermentation,  on  the  other 
hand,  will  be  longer,  according  as  the 
saccharine  principle  is  more  abundant, 
and  the  must  thicker. 

7th,  It  will  be  longer  if  the  wines  are 
destined  for  distillation ;  in  which  case, 
every  thing  ought  to  be  sacrificed  to  the 
production  of  alcohol. 

8th,  The  fermentation  will  be  longer, 
according  as  the  temperature  has  been 
colder,  when  the  grapes  were  collected. 

9th,  The  fermentation  will  be  longer, 
according  as  the  wine  is  required  to  be 
more  coloured. 

A  provident  agriculturist  will  always 
prepare  his  casks,  on  the  approach  of  the 
vintage,  in  such  a  manner  that  they  may 
be  ready  to  receive  the  wine  as  it  comes 
from  the  vat.  The  preparation  given  to 
them,  is  as  follows  ; 

If  the  casks  are  new,  the  wood  of  which 
they  are  composed  retains  an  astringency 
avid  bitterness,  which  may  be  transmitted 
to  the  wine ;  and  these  faults  may  be  cor- 
rected by  pouring  warm  water  and  salt 
4  d 


WIN 


WIN 


water,  into  them  several  times  in  succes- 
sion. These  liquors  must  be  well  shaken, 
and  suffered  to  remain  in  them 1  till  they 
penetrate  the  texture  of  the  wood,  and 
extract  the  pernicious  principle.  If  the 
casks  are  old,  and  have  been  frequent- 
ly employed,  one  end  of  them  is  opened  s 
the  stratum  of  tartar,  with  which  the  in- 
side is  covered,  is  scraped  off,  and  they 
are  washed  with  warm  water  or  with 
wine. 

In  general,  the  most  usual  methods  of 
preparing  the  casks  are  confined  to  the 
following. 

1st,  Wash  the  cask  with  cold  water, 
then  pour  into  it  a  quart  of  salt  water,  in 
a  state  of  ebullition ;  stop  the  bung-hole, 
and  shake  it  in  every  direction ;  empty  it, 
let  the  water  drain  well  off ;  then  take 
two  quarts  of  fermenting  must,  and,  hav- 
ing boiled  and  skimmed  it,  pour  it  boiling 
hot  into  the  cask;  close  it  and  again 
shake  it,  after  which  suffer  it  to  drain 
off. 

2d,  Warm  wine  may  be  employed  in- 
stead of  the  above  preparations 

3d,  An  infusion  of  the  flowers  of  the 
peach-tree,  &c,  may  also  be  used. 

When  the  casks  have  acquired  any  bad 
quality,  such  as  mustiness,  &c.  they  must 
be  burnt.  It  is  possible  to  conceal  these 
defects,  but  there  is  reason  to  fear  they 
might  re -appear. 

The  antient  Romans  put  gypsum,  myrrh 
and  various  aromatic  substances  into  the 
casks  into  which  their  wines  were  remov- 
ed from  the  vat.  This  is  what  they  call- 
ed conditura  vinorum.  The  Greeks  some- 
times added  a  little  bruised  myrrh  and 
argil.  These  substances  not  only  per- 
fumed the  wine,  but  served  also  to  clari- 
fy it. 

The  wine  of  the  press  is  the  less  colour- 
ed, accQ&ling  as  it  is  pressed  more  weak- 
ly and  more  speedily.  These  wines  in 
Champagne,  are  called  gray  wines.  The 
wine  arising  from  the  first  and  second 
cutting,  is  called  ceil  de  perdrix  ;  and  that 
arising  from  the  third  and  fourth,  vin  de 
taille.  The  last  is  the  most  coloured,  but 
still  agreeable. 

The  refuse,  when  strongly  pressed,  ac- 
quires sometimes  the  hardness  of  stone- 
It  is  applied  to  various  uses  in  com- 
merce. 

1st,  In  some  countries  it  is  distilled  in 
order  to  make  a  spirit,  which  is  called 
eau-de-vie  de  marc.  In  Champagne  it  is 
known  under  the  name  of  eau  d'Aixne ; 
but  it  has  a  bad  taste.  This  distillation 
is  advantageous,  especially  in  countries 
where  the  wine  is  highly  generous,  and 
where  the  presses  do  not  press  very 
closely  ; 


2d,  In  the  neighbourhood  of  Montpel- 
lier,  the  refuse  is  put  into  casks,  where 
it  is  carefully  trod  upon  ;  and  it  is  then 
preserved  for  making  verdigris. 

3d,  In  other  places  it  is  rendered  acid 
by  carefully  airing  it,  and  the  vinegar  is 
then  extracted  by  strong  pressure.  The 
expression  may  even  be  facilitated  by 
moistening  it  with  water. 

4th,  In  several  cantons  the  cattle  are 
fed  with  the  refuse.  As  it  comes  from  the 
press,  it  is  broken  with  the  hands  in  order 
to  divide  the  lumps;  it  is  then  thrown  in- 
to casks,  where  it  is  moistened  with  wa- 
ter, and  it  is  covered  with  earth  mixed 
with  straw.  This  covering  is  about  7  or 
8  inches  in  thickness.  When  bad  wea- 
ther prevents  the  cattle  from  going  out. 
into  the  fields,  about  6  or  7  pounds  of  this 
refuse  is  soaked  in  warm  water  with  bran, 
straw,  turnips,  potatoes,  oak,  and  vine 
leaves,  which  have  been  preserved  on  pur- 
pose in  water.  A  little  salt  may  be  added  to 
this  mixture,  which  is  given  to  the  cuttle 
in  a  tub  evening  and  morning.  Horses 
and  cows  are  fond  of  this  food  ;  but  it 
must  be  given  to  the  latter  in  moderation, 
because  it  would  cause  their  milk  to  turn 
sour.  The  refuse  of  white  grapes  is  pre- 
ferred on  account  of  its  not  having  been 
fermented. 

5th,  The  stones  contained  in  the  grapes 
serve  tor  feeding  poultry.  Oil,  also  may 
be  extracted  from  them. 

6th,  The  refuse  may  be  burnt  to  obtain 
alkali.  4000  pounds  of  refuse  yields  500 
pounds  of  ashes,  which  give  10  pounds  of 
dry  alkali. 

Of  the  method  of  managing  the  Wine  in 
the  Casks. 

The  wine  deposited  in  the  casks  has 
not  reached  its  last  degree  of  preparation . 
It  is  turbid,  and  still  ferments  ;  but,  as 
the  movement  of  it  is  less  tumultous,  this 
state  of  it  has  been  called  the  insensible 
fermentation. 

Soon  after  the  wine  has  been  put  into 
the  cask,  a  slight  hissing  is  heard,  which 
arises  from  the  continued  disengagement 
of  the  carbonic  acid  gas,  that  escapes 
from  every  point  of  the  liquor ;  foam, 
which  passes  over  through  the  bung-hole, 
is  formed  at  the  top,  and  care  is  taken  to 
keep  the  cask  always  full,  that  the  foam 
may  escape,  and  that  the  wine  may  dis- 
gorge itself.  For  a  short  time  it  will 
be  sufficient  to  fasten  a  piece  of  paper  on 
the  bung,  or  to  lay  a  tile  over  it. 

In  proportion  as  the  fermentation  de- 
creases the  mass  of  the  liquid  sinks  down ; 
and  this  depression  is  carefully  watched, 
in  order  to  pour  in  more  wine,  that  the 
casks  may  be  always  kept  full.  There. 


WIS 


WIN 


arc  some  countries  where  this  operation 
is  performed  every  day  for  the  first  month, 
every  four  days  for  the  second,  and  every 
eight  till  it  is  drawn  off.  This  is  the  me- 
thod practised  in  regard  to  the  delicious 
wines  of  the  Hermitage. 

Every  thing  that  relates  to  the  art  of 
preserving  wines,  may  be  reduced  to  sul- 
phuring and  clarification. 

Sulphuring  of  Wine. 

1st,  To  sulphur  wine  is  to  impregnate 
it  with  a  sulphurous  vapour,  obtained  by 
the  combustion  of  sulphured  matches. 

The  method  of  composing  these  match- 
es varies  considerably  in  different  places  ; 
some  mix  with  the  sulphur  aromatic  sub- 
stances, such  as  powder  of  cloves,  cinna- 
mon, ginger,  Florentine  iris,  flowers  of 
thyme,  lavender,  marjorum,  &.c.  and  melt 
the  mixture  in  an  earthen  vessel  over  a 
moderate  fire,  in  this  melted  mixture, 
rags  of  cotton  cloth  are  dipped  in  order  to 
be  burnt  in  the  casks.  Others  employ 
sulphur  alone,  which  they  melt  over  the 
fire,  and  dip  rags  in  it  in  the  same  man- 
ner. 

In  the  method  of  sulphuring  casks 
there  is  also  considerable  variety.  Some- 
times the  match  is  suspended  at  the  end 
<»f  an  iron  wire  ;  it  is  then  lighted,  and 
put  into  the  cask  intended  to  be  filled 
with  the  wine ;  the  cask  is  then  stopped, 
and  the  match  is  then  left  to  burn.  The 
internal  air  becomes  dilated,  and  is  ex- 
pelled, with  a  hissing  noise,  by  the  sul- 
phurous gas.  Two,  three,  or  more  match- 
es are  burnt  in  this  manner,  according  as 
may  be  thought  necessary.  When  the 
combustion  is  terminated,  the  sides  of  the 
cask  are  scarcely  acid ;  the  wine  is  then 
poured  into  it.  In  other  countries,  two 
or  three  pailsful  of  wine  are  poured  into  a 
good  cask ;  a  sulphured  match  is  then 
burnt  in  it ;  and  when  the  combustion  is 
finished,  the  cask  is  stopped,  and  shaken 
in  every  direction.  After  being  left  at  rest 
for  an  hour  or  two,  it  is  unstopped,  more 
wine  is  added ;  it  is  then  again  sulphured 
and  the  operation  is  repeated  till  the  cask 
be  full.  This  is  the  process  usually  fol- 
lowed at  Bordeaux. 

At  Marseillan,  near  the  commune  of 
Oette,  in  Languedoc,  a  kind  of  wine  is 
made  of  white  grapes,  called  mute  ivine, 
which  is  employed  to  sulphur  others.  The 
vintage  is  trod  and  pressed  without  giv- 
ing it  time  to  ferment ;  it  is  then  put  into 
casks  filled  one-fourth  j  several  matches 
are  burnt  over  it;  and  the  casks  are 
Mrongly  skaken,  until  no  more  gas  es- 
capes through  the  bung-hole  when  open- 
ed. A  new  quantity  of  wine  is  then  add- 
ed, matches  are  again  burnt  over  it,  and 


the  casks  are  shaken  with  the  same  pre- 
cautions. This  operation  is  repeated  till 
the  cask  is  full.  This  wine  never  fer- 
ments, and  for  that  reason  is  called  mute 
wine  (<vin  muet.)  It  has  a  sweetish  sa- 
vour, a  strong  sulphurous  odour,  and  is 
employed  for  mixing  with  other  wine. 
Two  or  three  bottles  of  it  are  put  into  a 
cask.  This  mixture  is  equivalent  to  sul- 
phuring. 

Sulphuring  first  renders  wine  turbid, 
and  gives  ii  a  bad  colour  ;  but  the  colour 
is  restored  in  the  course  of  time,  and  the 
wine  becomes  clear.  This  operation  whi- 
tens the  wine  a  little.  Sulphuring  is  at- 
tended with  the  very  valuable  advantage 
of  preventing  its  becoming  acetous.— 
Though  it  be  difficult  to  explain  this  ef- 
fect, it  appears  to  me  that  it  cannot  be 
conceived  but  by  considering  it  under 
two  points  of  view : 

1st,  By  the  help  of  the  sulphurous  gas 
the  atmospheric  air  is  displaced,  which 
otherwise  would  become  mixed  with  the 
wine,  and  determine  acid  fermentation. 

2d,  Some  atoms  of  a  violent  acid,  which 
opposes  and  overcomes  the  develope- 
ment  of  a  weaker  acid,  are  produced. 

The  an tients  composed  a  kind  of  mas- 
tic with  pitch,  a  fiftieth  part  of  wax,  and 
a  little  salt  and  incense,  which  they  em- 
ployed for  burning  in  their  casks.  This 
operation  was  denoted  by  the  words 
picare  dolia,  and  the  wines  thus  prepared 
were  known  under  the  names  of  vina 
pieafa.  They  are  mentioned  by  Plutarch 
and  Hippocrates. 

It  was,  perhaps,  in  consequence  of  this 
custom,  that  the  fir  was  consecrated  by 
the  antients  to  Bacchus.  At  present,  an 
agreeable  perfume  is  communicated  to 
weakened  red  wine,  by  making  it  remain 
over  a  stratum  of  the  shavings  of  fir. 
Baccius  says  that  the  casks  ought  to 
be  pitched  (picare  dolia)  during  the  dog 
days. 

On  the  Clarification  of  Wines. 
2d,  Besides  the  operation  of  sulphur 
ing  wines,  there  is  another,  no  less  essen  ■ 
tial,  called  clarification.  It  consists,  in 
the  first  place,  in  drawing  off  the  wine 
from  the  lees,  which  requires  certain 
precautions,  and  in  then  disengaging  it 
from  all  the  principles  suspended  or  weak- 
ly dissolved  in  it ;  so  that  nothing  may  be 
retained  but  the  spirituous  and  incorrupt- 
ible principles  alone.  These  operations 
are  even  performed  before  that  of  sul- 
phuring, which  is  only  a  continuation  of 
them 

The  first  of  these  operations  is  called 
drawing  off,  transvasation,  defecation.  Ac- 
cording to  Aristotle,  this  ought  to  be  oft« 


WIN 


WIN 


cn  repeated :  quoniam  superveniente  xsta- 
tis  calore  solent  faeces  subverti,  ac  ita  vina 
acescere. 

In  the  different  wine  countries,  there 
are  certain  fixed  periods  of  the  year  for 
this  operation,  established,  no  doubt,  on 
the  constant  and  respectable  observation 
of  apes.  \t  the  Hermitage,  tbe  wine  is 
drawn  off  in  March  an  I  September ;  in 
Champagne,  on  the  13th  of  Occober,  about 
the  M»th  of  February,  and  towards  the  end 
of  March. 

Dry,  cold  weather  is  always  chosen  for 
this  operation.  It  is  certain  that  it  is  then 
onb  that  the  wine  is  in  a  good  condition 
Damp  weather,  and  southerly  winds,  al- 
ways render  wine  turbid  ;  and  care  must 
be  taken  not  to  draw  it  off  while  these 
prevail. 

Baccius  has  left  some  excellent  pre- 
cepts respecting1  the  most  favourable  pe- 
riods for  the  defecation  of  wine.  He  ad- 
vises the  weakest  wines,  that  is  to  say, 
those  produced  from  fat  covered  soil,  to 
be  drawn  off  at  the  winter  solstice  ;  mo- 
derate wines  in  the  spring- ;  and  the  most 
generous,  during  summer-  He  gives  as 
a  general  precept,  not  to  draw  oft"  the 
wine  but  when  the  north  wind  prevails  ; 
and  he  adds,  that  wire  drawn  oft"  at  the 
time  of  the  full  moon,  is  converted  into 
vinegar ! 

The  manner  in  drawing  off  wine  can  be 
a  matter  of  indifference  only  to  those  un- 
acquainted with  the  eflect  of  atmospheric 
air  on  that  liquid.  By  opening  the  tap, 
or  placing  a  cock  at  about  four  inches 
from  the  bottom  of  the  cask,  the  wine 
which  runs  off  becomes  aerated,  and  de- 
termines movements  in  the  lees  ;  so  that, 
under  this  double  view,  the  wine  acquires 
a  disposition  to  become  sour.  A  past  of 
these  inconveniences  has  been  obviated 
by  drawing  off  the  wine  by  means  of  a 
syphon  :  the  motion  is  then  gentler,  and 
by  these  means  one  may  penetrate  to  any 
depth  at  pleasure,  without  agitating  the 
lees.  But  all  these  methods  are  attend- 
ed with  faults,  which  have  been  com- 
pletely remedied  by  the  help  of  a  pump, 
the  use  of  which  has  been  established  in 
Champagne  and  other  wine  countries. 

To  a  leathern  pipe,  of  from  four  to  six 
feet  in  length,  and  two  inches  in  diameter, 
are  adapted  at  each  end  wooden  pipes, 
nine  or  ten  inches  in  length,  which  de- 
crease in  diameter  towards  the  ends,  and 
are  fixed  to  the  leathern  pipe  by  means  of 
a  piece  of  pack-thread.  The  bung  of  the 
cask  intended  to  be  filled,  is  taken  out, 
and  one  of  the  extremities  of  tiie  pipe  is 
put  into  it.  A  good  cock  is  fixed  in  the 
cask  to  be  emptied,  two  or  three  inches 


from  the  bottom,  and  into  this,  is  inserted 

the  other  extremity  of  the  pipe. 

By  tin's  mechanism  alone,  the  half  of 
the  one  cask  is  emptied  into  the  other. 
For  this  purpose  nothing  is  necessary  but 
to  open  the  cock ;  and  the  remainder  may 
be  made  to  pass  by  a  very  simple  process, 
for  which  a  pair  of  beliows,  about  two 
feet  in  length,  comprehending  the  han- 
dles, and  ten  inches  in  breadth,  are  em- 
ployed. The  bellows  force  the  air  through 
a  hole  formed  at  the  anterior  part  of  the 
small  end.  A  small  leathern  valve,  placed 
below  the  small  hole,  prevents  the  air 
from  rushing  out  when  the  bellows  are 
opened  and  to  the  extremity  of  the  bel- 
lows is  adapted  a  perpendicular  wooden 
pipe  to  convey  the  air  downwards.  This  N 
tube  is  fitted  into  the  bung-hole  in  such  a 
manner,  that  when  the  bellows  are  work- 
ed and  the  air  forced  out,  a  pressure  is 
exercised  on  the  wine,  by  which  means 
it  is  obliged  to  issue  from  the  one  cask, 
and  io  ascend  into  the  other.  When  a 
hissing  is  heard  at  the  cock,  it  is  speedily 
shut.  This  is  a  sign  that  all  the  wine  has 
passed. 

Funnels  of  tin  plate,  the  tubes  of  which 
are  at  least  a  foot  and  a  half  in  length, 
that  they  may  be  immersed  in  the  liquor 
without  causing  any  agitation,  are  also 
employed. 

Drawing  off  Wine  separates  a  part  of 
its  impurities,  and  consequently  removes 
some  of  those  causes  which  may  alter  the 
quality  of  it.  But  there  still  remain  some 
suspended  in  the  liquor,  which  cannot 
be  caught,  but  by  the  following  opera* 
tions,  which  are  called  fining  of  wine,  or 
clarification.  Fishglue  (isinglass)  is  al- 
most always  employed  for  this  purpose. 
It  is  unrolled  with  care,  and  cut  into  small 
morsels,  and  it  is  then  steeped  in  a  little 
wine,  where  it  swells  up,  becomes  soft, 
and  forms  a  viscid  mass,  which  is  poured 
into  the  wine.  The  wine  is  then  strongly 
agitated,  after  which  it  is  left  at  rest. 
Some  whip  the  wine,  in  which  the  glue 
has  been  dissolved,  with  a  few  twigs  of 
birch,  &c.  and  by  these  means  occasion  a 
considerable  foam,  which  is  carefully  re- 
moved. In  all  cases  a  portion  of  the  glue 
is  precipitated  with  the  principles  it  has 
enveloped,  and  the  liquor  is  drawn  off 
when  the  deposit  is  formed. 

A  quarter  cask  of  wine,  may  be  well 
fined  by  drawing  off  about  a  quart  of  it, 
and  mixing  this  well  with  a  half  a  pint  of 
new  milk:  which  mixture  is  then  to  be  put 
into  the  wine,  and  the  cask  well  shaken, 
or  rolled  about.  Then  place  the  cask  in 
the  position  in  which  it  is  to  remain,  tak- 
ing care  that  it  be  so  situated  as  to  be  in  3 


AVIN 


WIN 


state  of  perfect  rest,  and  in  a  few  days  the 
wine  will  be  completely  clear  and  fit  for 
use. 

In  warm  climates  the  use  of  the  glue  is 
dreadi  d,  .ond  during  summer  its  places  is 
.supplied  by  whites  of  eggs.  Ten  or 
twelve  are  sufficient  for  half  a  muid  (about 
a  72  gallon  cask  English  )  The  eggs  are 
first  beat  up  with  a  little  wine  j  they  are 
then  mixed  with  the  liquor  intended  to 
be  clarified,  and  it  is  whipped  with  the 
same  care.  It  is  possible  that  gum  arabic 
might  be  substituted  for  glue.  Two 
ounces  will  be  sufficient)  for  four  hundred 
pot  s  (  f  wine.  It  is  put  into  the  liquor  in 
the  form  of  a  fine  powder,  and  the  liquor 
is  ti.en  stirred. 

Wine  must  not  be  drawn  off,  till  it  is 
completely  made.  If  the  wine  is  green 
and  harshj  it  must  be  suffered  to  ferment 
a  second  time  on  the  lees,  and  must  not 
be  drawn  off  till  towards  the  middle  of 
May  ;  if  it  continues  green,  it  may  even 
be  left  till  the  end  of  June.  It  even 
sometimes  happens  that  it  is  necessary  to 
convey  back  the  wine  to  the  lees,  and  to 
mix  them  strongly,  that  the  wine  may 
again  acquire  that  movement  of  fermen- 
tation which  is  necessary  to  bring  it  to 
perfection. 

,  We  are  told  by  Miller,  that  when  Spa- 
nish wine  becomes  turbid  by  the  lees,  it 
may  be  clarified  by  the  following  pro- 
cess : 

Put  the  whites  of  eggs,  gray  salt,  and 
salt  water,  into  a  convenient  vessel ;  skim 
off'  the  foam  formed  at  the  surface,  and 
pour  the  composition  into  the  wine  cask 
from  which  a  part  of  the  liquor  has  been 
drawn  off.  At  the  end  of  two  or  three 
days  the  liquor  becomes  clear,  and  ac- 
quires an  agreeable  taste.  After  being 
suffered  to  remain  at  rest  for  about  a  week, 
it  is  then  drawn  off 

To  revive  claret  injured  by  floating  lees, 
two  pounds  of  calcined  flints,  well  pound- 
ed, ten  or  twelve  eggs,  and  a  large  hand- 
ful of  salt,  are  beat  up  with  two  gallons  of 
wine,  which  are  then  poured  into  the 
cask.  Two  or  three  days  after,  the  wine 
is  drawn  off. 

These  compositions  may  be  varied  with- 
out end.  Sometimes  starch  is  employed, 
and  also  rice,  milk,  and  other  substances, 
more  or  less  capable  of  developing  the 
principles  which  render  the  wine  tur- 
bid. 

Wine  is  clarified  also,  and  its  bad  taste 
is  often  corrected,  by  making  it  digest 
over  shavings  of  beech  wood,  previously 
stripped  of  the  bark,  boiled  in  wrater,  and 
dried  in  the  sun,  or  in  a  stove.  A  quar- 
ter of  a  bushel  of  these  shavings  will  be 
sufficient  for  a  muid  of  wine.   They  pro- 


duce a  light  movement  of  fermentation  in 
the  liquor,  which  becomes  clear  in  the 
course  of  twenty -four  hours. 

The  art  of  cutting  loines  (couper  du  vin) 
as  it  is  called,  (correcting  one  wine  by 
another — giving  a  body  to  those  wines 
which  are  weak — colour  to  those  desti- 
tute of  it — and  an  agreeable  flavour  to 
those  winch  have  none,  or  which  have  a 
bad  one)  cannot  be  described.  In  these 
cases,  the  taste,  sight,  and  smell  must  be 
consulted.  The  highly  variable  nature  of 
the  substances  employed,  must  be  studied  : 
and  it  will  be  sufficient  for  us  to  observe, 
that  in  this  part  of  the  management  of 
wines,  every  thing  consists  :  1st,  in  sweet- 
ening wines,  and  rendering  them  saccha- 
rine by  the  addition  of  baked  must,  con- 
centrated with  honey,  sugar,  or  another 
wine  of  a  very  luscious  quality.  2d,  co- 
louring the  wine  by  an  infusion  of  turn- 
sole cakes,  the  juice  of  elder-berries,  log- 
wood, and  mixing  it  with  dark,  and,  ge- 
nerally, coarse  wine.  3d,  perfuming  it 
by  syrup  of  rasberries,  an  infusion  of  the 
flowers  of  the  vine,  suspended  in  the  cask, 
tied  up  in  a  bag,  as  is  practised  in  Egypt, 
according  to  the  testimony  of  Hassel- 
quist. 

Whatever  may  be  the  nature  of  the  ves 
sels  destined  to  contain  wine,  a  cellar 
sheltered  from  all  accidents  must  be  cho. 
sen. 

1st,  The  exposure  ofthe  cellar  must  bp 
northern.  Its  temperature  is  then  less 
variable,  than  when  the  apertures  arr 
turned  towards  the  south. 

2d,  It  must  be  of  such  a  depth  that  the 
temperature  may  be  constantly  the  same 
In  cellis  quae  non  satis  profunda  sunt  diumi 
caloris  participes  jiunt ;  vina  non  din  subsis- 
tunt  integra,  says  Hoffman. 

3d,  The  moisture  in  it  must  be  con 
stant,  without  being  too  great :  excess  of 
moisture  renders  the  papers,  corks,  casks, 
&c.  mouldy.  Dryness  desiccates  the  casks 
and  makes  them  leak. 

4th,  The  light  ought  to  be  very  mode 
rate.  A  strong  light  dries;  darkness,  al 
most  absolute,  rots. 

5th,  The  cellar  must  be  sheltered  from 
shocks.  Violent  agitation,  or  that  shaking 
occasioned  by  the  rapid  passage  of  cat 
riages  along  the  street,  agitates  the  lees, 
mixes  them  with  the  wine,  where  they 
are  kept  suspended,  and  occasions  acetifi- 
cation.  Thunder,  and  all  movement  oc 
casioned  by  shocks,  produce  the  same  ef 
feet. 

6th,  Green  wood,  vinegar,  and  all  sub. 
stances  susceptible  of  fermentation,  musl 
be  kept  at  a  distance  from  the  cellar. 

7th,  The  reverberation  of  the  son, 


WIN 


WIN 


which,  as  it  necessarily  changes  the  tem- 
perature of  a  cellar,  must  also  alter  the 
properties  of  the  wine  preserved  in  it, 
ought  also  to  be  guarded  against. 

A  cellar,  therefore,  must  be  dug  to  the 
depth  of  some  fathoms  below  ground  ;  its 
apertures  ought  to  be  directed  towards 
the  north  ;  it  must  be  at  a  distance  from 
the  street,  highways,  workshops,  sewers, 
necessaries,  he.  and  ought  to  be  arched 
at  the  top. 

•Maladies  of  Wine,  and  the  Means  of  Pre. 
venting  or  Correcting  them. 

There  are  some  wines  which  improve 
by  age,  and  which  cannot  be  considered 
as  perfect,  till  a  long  time  after  they  have 
been  made.  Luscious  wines  are  of  this 
kind,  as  well  as  highly  spirituous  wines  ; 
but  delicate  wines  are  so  apt  to  turn  sour, 
or  oily,  that  it  is  only  by  means  of  great 
precaution,  that  they  can  be  preserved 
for  several  years. 

Among  the  diseases  to  which  wines  are 
most  subject,  oiliness  and  acidity,  are  the 
most  common  and  most  dangerous. 

Oiliness  is  an  alteration  which  wines 
often  contract :  they  lose  their  natural 
fluidit}'1,  and  become  ropy,  like  oil. 

The  less  spirituous  wines  turn  oily  ; 
and  weak  wines,  which  have  fermented 
very  little,  are  the  most  disposed  to  this 
malady.  Weak  wines,  made  from  grapes 
which  have  been  picked,  are  also  subject 
to  it. 

Wine  turns  oily  in  the  best  corked  bot- 
tles. Of  this  there  are  too  frequent  in- 
stances in  Champagne,  where  the  wine  of 
a  whole  vintage,  when  put  into  class  ves- 
sels, is  exposed  sometimes  to  this  altera- 
tion. 

Oily  wines  furnish  by  distillation,  but  a 
little  fat  coloured  and  oily  spirit. 

This  fault  may  be  corrected  several 
ways. 

1.  By  exposing  the  bottles  to  the  air, 
and,  above  all,  in  a  well-aired  barn, 

2-  By  shaking  the  bottle  for  a  quarter 
of  an  hour  ;  then  uncorking  it,  and  suf- 
fering the  gas  and  foam  to  escape. 

3  By  mixing  the  wine  with  fish-glue, 
and  whites  of  eggs  mixed  together. 

4.  By  introducing  into  each  bottle  one 
or  two  drops  of  lemon  juice,  or  any  other 
acid. 

Acescence  of  wine  is  however  the  most 
common  malady,  and  we  may  even  say, 
the  most  natural,  for  it  is  almost  a  con- 
sequence of  spirituous  fermentation  ;  but 
by  knowing  the  cause  which  produces  it, 
and  the  phenomena  which  accompany  or 
announce  it,  means  may  be  taken  to  pre- 
vent it.  The  antients  admitted  three  prin- 
cipal causes  of  the  acidity  of  wines. 


1.  The  humidity  of  the  wine. 

2.  The  inconstancy  or  variations  of  the 

atmosphere. 

3.  Commotions. 

To  know  this  malady  exactly,  we  must 
call  to  mind  some  principles,  which  can 
alone  furnish  us  with  light  on  this  subject. 

1.  Wine  never  turns  sour,  until  the  spi- 
rituous fermentation  is  terminated  ;  or, 
in  other  words,  till  the  saccharine  piinci- 
ple  is  completely  decomposed.  Hence 
the  advantage  of  putting  wine  into  casks 
before  all  the  saccharine  principle  has 
disappeared  ;  because  the  spirituous  fer- 
mentation then  continues,  is  prolonged, 
and  removes  every  thing  that  can  pave  the 
way,  for  acetous  decomposition.  Hence 
tiie  practice  of  putting  a  little  sugar  into 
the  bottle,  to  preserve  the  wine  without 
alteration  ;  and  hence  the  general  method 
of  baking  a  part  of  the  must,  at  a  slow 
and  moderate  heat,  and  of  mixing  some 
of  it  in  the  casks,  intended  for  embarka- 
tion. In  some  places  of  Spain  and  Italy, 
all  the  must  is  baked  ;  and  Bellon  says, 
that  the  wines  of  Crete  would  not  keep 
at  sea,  unless  the  precaution  were  taken 
to  boil  them. 

2.  The  least  spirituous  wines,  are  those 
which  soonest  become  sour.  We  know, 
by  experience,  that  when  the  season  is 
rainy,  if  the  grapes  be  a  little  saccharine, 
which  consequently  gives  a  little  alcohol, 
the  wines  readily  turn  sour.  The  weak 
wines  of  the  north,  become  sour  with  great 
ease  ;  while  the  strong,  generous,  spiri- 
tuous wines,  obstinately  resist  acidity. 

It  is  however  no  less  true,  that  the  most 
spirituous  furnish  the  strongest  vinegar, 
though  their  acetification  is  more  diffi- 
cult, because  alcohol  is  necessary  to  the 
ibrmation  of  vinegar. 

3.  Wine,  perfectly  free  from  all  extrac- 
tive matter,  either  in  consequence  of  its 
being  deposited  naturally,  by  time  or  by 
clarification,  is  not  susceptible  of  turning 
sour.  1  have  exposed  old  wine  in  uncork- 
ed bottles,  to  the  ardour  of  the  sun  of  July 
and  August,  for  more  than  forty  days, 
without1  the  wine  losing  its  quality  ;  only 
the  colouring  principle  was  constantly 
precipitated  under  the  form  of  a  mem- 
brane, which  covered  the  bottom  of  the 
bottle.  The  same  wine,  in  which  I  infus- 
ed vine-leaves,  became  sour  in  a  leu  day  s. 
It  is  known  that  old  wines,  well  purified, 
do  not  turn  sour. 

4.  While  does  not  acidify,  or  become 
sour,  but  when  in  contact  with  the  air  • 
atmospheric  air  mixed  with  wine,  is  a  real 
leaven  of  acidity.  When  wine  grows  flat, 
{se pousse)  it  suffers  to  escape,  or  exhales, 
the  gas  it  contains,  and  the  external  ait- 
then  enters  to  assume  its  place. 


WIN 


WIS 


5.  There  are  certain  times  in  the  year, 
when  the  wine  turns  more  readily  sour. 
These  periods  are,  the  moment  when  the 
sap  rises  in  the  vine,  when  it  flowers,  or 
when  the  grapes  assume  a  reddish  tint. 
It  is  during  these  periods,  in  particular 
that  precautions  must  be  taken,to  prevent' 
its  becoming  acid. 

6.  Change  in  the  temperature  also  pro- 
motes acidity,  especially  when  the  heat 
rises  to  80  or  90  degrees,  Fahr.  The 
degeneration  is  then  rapid,  and  almost  un- 
avoidable. 

The  acidity  of  wine  may  be  easily  pre- 
vented, by  removing  all  those  causes  be- 
fore-mentioned, which  tend  to  produce 
this  alteration;  and  when  it  has  begun, 
it  may  be  remedied  by  the  means,  more 
or  less  effectual,  which  we  are  going  to 
mention. 

Baked  must,  honey,  or  liquorice,  are 
dissolved  in  wine,  in  which  acidity  has 
manifested  itself;  by  these  means  its  sour 
taste  is  corrected,  being  concealed  by  the 
sweetish  savour  of  these  ingredients. 

The  little  acid  which  has  been  formed, 
may  be  seized  by  the  means  of  ashes,  al- 
kalies, chalk,  lime,  and  even  litharge.— 
This  last  substance,  which  forms  a  very 
sweet  salt  with  acetous  acid,  is  exceed- 
ingly dangerous. 

Thb  works  of  oinologists  abound  with 
recipes,  of  greater  or  less  value,  tor  cor- 
recting the  acidity  of  wine. 

Bidet  says,  that  about  a  50th  of  skim- 
med milk,  added  to  sour  wine,  restores 
it ;  and  that  it  may  be  drawn  off  in  five 
days. 

Others  take  four  ounces  of  the  best 
wheat,  boil  it  in  water  till  it  bursts  ;  and, 
when  it  has  cooled,  put  it  into  a  small  bag, 
which  is  immersed  in  the  cask,  shaking 
it  with  a  stick. 

Some  recommend  also  the'  seeds  of 
leeks,  fennel,  &c. 

To  show  the  futility  of  the  greater  part 
of  these  remedies,  it  will  be  sufficient  to 
observe,  that  it  is  impossible  to  make  fer- 
mentation proceed  in  a  retrograde  man- 
ner.and  that  it  can,  at  most,  be  suspended; 
that  the  whole  of  the  acid  then  formed, 
may  be  seized,  or  its  existence  may  be 
concealed,  by  sweet  and  saccharine  prin- 
ciples. 

But  besides  these  alterations,  there  are 
others,  which,  though  less  common  and 
dangerous,  deserve \o  be  noticed.  Wine 
sometimes  contracts,  what  is  called  a  taste 
of  the  cask.  This  malady  may  arise  from 
two  causes. 

1.  When  the  wine  is  put  into  casks, 
lie  wood  of  which  is  rotten  or  damaged. 

2.  When  lees  have  been  left  to  dry  in 
the  casks,  into  which  new  wine  is  put.— 


Willcrmoz  proposes  lime-water,  carbonic 
acid,  and  oxygenated  muriatic  acid,  to 
correct  the  bad  taste  arising  from  the 
cask  :  others  recommend  mixing  the  wine 
with  isinglass,  drawing  it  carefully  off, 
and  infusing  roasted  wheat  in  it  for  two 
or  three  days. 

A  phenomenon,  which  has  struck  and 
embarrassed  the  numerous  authors  who 
have  spoken  of  the  diseases  of  wine,  is 
what  is  called  the  flowers  of  wine.  These 
are  formed  in  casks,  but  particularly  in 
bottles,  in  which  they  occupy  the  neck  ; 
they  constantly  announce  and  precede  the 
acid  degeneration  of  wine.  They  mani- 
fest themselves  in  almost  all  fermented 
liquors,  and  always  more  or  less  abun- 
dantly, according  to  the  quantity  of  ex- 
tractive matter,  existing  in  the  liquor. 

Uses  and  Virtues  of  Wine. 

Wine  has  become  the  most  useful  be- 
verage of  man,  and  is,  at  the  same  time, 
the  most  varied.  Wine  is  known  in  all 
climates  ;  and  the  attraction  of  this  liquor 
is  so  strong,  that  the  prohibitory  law  re- 
specting it,  which  Mahomet  imposed  on 
his  followers,  is  daily  broken. 

This  liquor,  besides  being  a  tonic  and 
strengtheuer,  is  also  more  or  less  nutri- 
tive ;  in  every  point  of  view,  it  must  be 
salutary.  The  antients  ascribed  to  it  the 
property  of  strengthening  the  understand- 
ing. Plato,  yEschylus,  and  Solomon,  all 
agree,  in  ascribing  to  it  this  virtue.  But 
no  writer  has  better  described  the  real 
properties  of  wine,  than  the  celebrated 
Galen,  who  assigns  to  each  sort  its  pecu- 
liar uses,  and  describes  the  difference 
they  acquire  by  age,  climate,  &c. 

Excess  in  regard  to  the  use  of  wine,  has 
at  all  times  called  forth  the  censure  of 
legislators.  It  was  customary  among  the 
Greeks  to  prevent  intoxication,  by  rub- 
bing their  temples  and  forehead,  with 
precious  ointments  and  tonics.  The  anec- 
dote of  that  famous  legislator,  who  to  re- 
strain the  intemperance  of  the  people, 
authorized  it  by  an  express  law,  is  well 
known  ;  and  we  read  that  Lycurgus  caus- 
ed drunken  people  to  be  publicly  exhi- 
bited, in  order  to  excite  a  horror  of  intoxi- 
cation in  the  Lacedaemonian  youth.  By  a 
law  of  Carthage,  the  use  of  wine  was  prohi- 
bited in  the  time  of  war.  Plato  interdict- 
ed it  to  young  persons  below  the  age  of 
twenty-two.  Aristotle  did  the  same  to 
children  and  nurses.  And  we  are  informed 
by  Palmarius,  that  the  laws  of  Rome  al- 
lowed to  priests,  or  those  employed  in 
the  sacrifices,  but  three  small  glasses  of 
wine  at  their  repasts. 
But,  notwithstanding  the  wisdom  cT 


WIN 


WOA 


laws  the  hideous  picture  of  intemperance,  I  more  oily,  more  nutritive,  and  more  gase- 
and  the  fatal  consequences  with  which  it  ous,  than  the  red. 

is  attended,  the  attractions  of  wine  have  I  Piiny  admits  four  shades,  in  the  colour 
been  so  powerful  among  certain  nations,  I  of  wines  :  album,  fulvum,  sanguineum,  ru- 


brum:  but  it  would  be  too  minute  as  well 
as  useless  to  multiply  shades,which  might 
become  infinite,  by  extending  them  from 
;  black  to  white 

Climate,  culture,  and  variety,  in  the 
t  processes  of  fermentation,  produce  also 
'  infinite  differences  in  the  qualities  and 
virtues  of  wine.   To  avoid  repetitions,  we 
must  refer  to  what  we  have  already  said 
on  this  subject 

The  art  of  tempering'  wine,  by  the  ad- 
dition of  one  part  of  water,  was  practised 
among  the  antients  :  wine  of  this  kind 
they  called  vinum  ciilutum.    Pliny,  after 
I  Homer,  speaks  of  a  wine,  which  could 
bear  20  parts  of  water.    The  same  histo- 
j  rian  informs  us,  that  in  his  time,  wines  so 
i  spirituous  were  known,that  they  could  not 
be  drunk:  nisi pervinca  entur  aqua  et  at- 


that  their  fondness  for  it  lias  degenerated 
into  a  passion,  and  real  want.  We  daily 
see  men,  prudent  in  other  respects,  gra- 
dually acquire  the  habit  of  indulging  im- 
moderately, in  the  use  of  this  liquor  ;  and, 
in  their  wine,  extinguish  their  moral  fa- 
culties, and  their  physical  strength. 

The  virtue  of  wine  differs  according  to 
its  age.  New  wine  is  flatulent,  indigesti- 
ble, and  purgative  :  mustum  fiatuosum  et 
concoctu  difficile.  Unum  in  se  bonum  con- 
tinst,  quod  alvum  emolliat.  Vinum  rarum 
inf rigid  at  g  mustum  crassi  succi  esty  et 
frigidi. 

The  antients  confounded  these  words  ; 
mustum  et  novum  vinum.  Ovid  says,  Qui 
nova  musta  bibant.  Unde  virgo  musta 
dicta  est  pro  intacta  et  novella. 

Light  wines  only  can  be  drank,  before 
they  have  grown  old.  The  reason  we  |  tenuarentur  aqua,  calida 
have  mentioned,  in  the  preceding  pages.  I  The  antients,  who  had  very  just  and 
The  Romans,  as  we  have  observed,  fol-  ■  correct  ideas,  respecting  the  art  of  mak- 
lowed  this  custom,  and  drank  their  wines  j  fag  and  preserving  wines,  seem  to  have 
in  succession  :  Vinum  Gauranum  et  Alba-  been  unacquainted  with  that  of  distilling 
num,  etquce  in  Sabinis  et  in  Tuscis nascun-  spirit  from  them  .  the  first  correct  ideas 

respecting  the  distillation  of  wine,  are  as- 
cribed to  Arnaud  de  Villeneuve,  profes- 
sor of  medicine  at  Montpellier. 

WIPERS  OF  STAMPERS.  See  Me- 
chanics.  See  also  Weaving  by  Pow- 
er Looms. 

WIRE.  See  Iron,  and  Manufac- 
ture of  Iron. 

WOAD.  On  the  cultivation  and  manu- 
facture of,  in  a  letter  to  the  Bath  and 
West  of  England  Agricultural  Society,  by 
Mr.  John  Parrish. 

Woad  is  a  plant  which,  combined  with 
indigo,  gives  the  best  and  most  perma- 
nent blue  dye  hitherto  discovered. 

This  plant  is  cultirated  in  different  part  s 
of  England  for  the  use  of  the  dyers,  as 
well  as  in  France,  Germany,  &c.  It  is  best 
to  sow  the  seeds  in  the  month  of  March, 
or  early  in  April,  if  the  season  invite,  and. 
the  soil  be  in  condition  to  receive  it ;  but 
it  requires  a  deep  loamy  soil,  and  is  bet- 
ter still  with  a  clay  bottom,  such  as  is  nov 
subject  to  become  dry  too  quickly.  It 
must  never  be  flooded,  but  situated  so  as 
to  drain  its  surface,  that  it  may  not  be 
poisoned  by  any  water  stagnant  upon 
it. 

If  (at  any  reasonable  price)  meadow 
land  to  break  the  turf  can  be  obtained,  it 
will  be  doubly  productive.  This  land  is 
generally  freest  from  weeds  and  putrid 
matter,  though  sometimes  it  abounds  with 
botts,  grubs,  and  snails.   However,  it 


tur>  et  Amienum  quod  circa  JYeapolim  vici- 
nis  collibus  gignitur. 

New  wines  are  not  all  nourishing,  espe- 
cially those  which  are  aqueous,  and  little 
saccharine  :  corpori  alimentum  suggerunt 
paucissimum,  says  Galen. 

These  wines  readily  produce  intoxica- 
tion ;  and  the  reason  of  this  is,  the  quan- 
tity of  carbonic  acid  with  which  they  are 
charged.  This  acid,  by  disengaging  it- 
self from  the  liquor  by  the  temperature 
of  the  stomach,  extinguishes  the  irri- 
tability of  the  organs,  and  brings  on  stu- 
por. 

Old  wines,  in  general,  are  tonic,  and 
very  wholesome  ;  they  are  suited  to  weak 
stomachs,  old  people,  and  in  all  cases 
v.  here  strengthening  is  necessary :  they 
afford  very  little  nourishment,  because 
they  are  deprived  of  their  really  nourish- 
ing principles,  and  any  other  than  alco- 
hol. 

Oily  thick  wines  are  the  most  nourish- 
ing. Pinguia  sanguinem  augent  et  nutriunt ; 
Galen.  The  same  author  recommends 
the  wines  of  Therea  and  Scibellia  as 
highly  nourishing :  quod  crassum  utrum- 
quet  nigrum  et  dulce. 

Wines  differ  also  essentially  in  regard 
to  colour.  Red,  in  general,  is  more  spiri- 
tuous, lighter,  and  more  digestible :  white 
wine  furnishes  less  alcohol,  and  is  more 
diuretic  and  weaker,  and  has  remained 
Jess  time  in  the  vat :  it  is  almost  always 


WO  A 


WOA 


saves  much  expense  in  weeding";  and  ju- 
dicious management  will  get  rid  of  these 
otherwise  destructive  vermin.  A  season 
of  warm  showers,  not  too  dry  or  too  wet, 
gives  the  most  regular  crop,  and  produces 
the  hest  woad. 

If  woad  is  sown  on  corn  land,  much  ex- 
pense generally  attends  hoeing  and  weed- 
ing; and  here  it  will  require  strong  ma- 
nure, though  on  leys  it  is  seldom  much 
necessary,  yet  land  cannot  be  too  rich  for 
woad.  On  rich  land,  dung  should  be 
avoided,  particularly  on  leys,  to  avoid 
weeds.  Some  people  sow  it  as  grain,  and 
harrow  it  in,  and  afterwards  hoe  it  as  tur- 
nips, leaving  the  plants  at  a  distance,  in 
proportion  to  the  strength  of  the  land; 
others  sow  it  in  ranks  by  a  drill-plough  ; 
and  some  dibble  it  in,  (in  quincunx  form, 
by  a  stick,  with  a  peg  crossways,  about 
two  or  two  and  a  half  inches  froni  the 
point,  according  to  the  land)  putting  three 
or  four  seeds  in  a  hole,  ami  these  holes  to 
be  from  twenty  inches  to  two  feet  apart, 
accoi  ding  to  the  richness  of  the  land  ;  for 
good  land,  if  room  be  given,  will  produce 
very  luxuriant  plants  in  good  seasons ;  but 
if  too  nearly  planted,  so  that  air  cannot 
circulate,  they  do  not  thrive  so  well.  At- 
tention to  this  is  necessary  in  every  way  of 
sowing  it.  Woad  very  often  fails  in  its 
crop,  from  the  land  not  being  in  condi- 
tion, or  from  want  of  knowing  how  to  de- 


stroy  the  botts,  snails,  w  ire  worms 
that  so  often  prey  upon,  and  destroy  it,  as 
well  as  from  inattention  to  weeding,  &,c. 
Crops  fail  also  from  being  sown  on  land 
that  is  naturally  too  dry,  and  in  a  dry  sea- 
son ;  but  as  the  roots  take  a  perpendicu- 
lar direction,  and  run  deep,  such  land  as 
1  have  described  (with  proper  attention  to 
my  observations)  will  seldom  fail  of  a 
crop ;  and  if  the  season  will  admit  sowing 
early  enough,  to  have  the  plants  strong 
before  the  hot  and  dry  weather  comes  on, 
there  will  be  almost  a  certainty  of  a  great 
produce. 

These  plants  are  frequently  destroyed 
in  the  germination  by  flies,  or  animalcule, 
and  by  grubs,  snails,  &c.  as  before  obser- 
ved; and  in  order  to  preserve  them,  the 
seeds  may  be  steeped  with  good  success, 
in  lime  and  soot,  until  they  begin  to  vege 
tate ;  first  throwing  half  a  load  or  more 
of  flour  lime  on  the  acre,  and  harrowing 
it  in.  Then  plant  the  seeds  as  soon  as  they 
break  the  pod,  taking  care  not  to  have 
more  than  one  day's  seed  ready  ;  for  it  is 
better  to  be  too  early,  than  to  have  their 
vegetation  too  strong  before  it  is  planted, 
lestthey  should  receive  injury  ;  yet  I  have 
never  observed  any  injury  in  mine  from 
this,  though  I  have  often  seen  the  shoot 
VOL.  1 


strong.   Either  harrows  or  rollers  will 
close  the  holes.    If  the  ground  be  moist  it 
will  appear  in  a  few  days  ;  but  it  will  be 
safe,  and  a  benefit  to  the  laud,  to  throw 
more  lime  on  the  surface,  when,  if  it  show- 
ers invite  snails  and  grubs  to  eat  it,  they 
will  be  destroyed,  which  I  have  several  - 
times  found  ;  particularly  once,  when  the 
leaves  were  two  inches  lung,  and  in  drills 
very  thick  and  strong,  but  the  ground 
was  dry.    When  a  warm  rain  fell,  in  less 
than  two  hours  I  found  the  ranks  on  one 
side  attacked  by  these  vermin,  and  eaten 
entirely  oflf  by  a  large  black  grub,  thou- 
sands of  which  were  on  the  leaves,  and 
they  cleared  as  they  went,  not  going  on 
until  they  iiad  destroyed  every  leaf  where 
they  fixed.    They  had  eaten  six  or  seven 
ranks  before  I  was  called  by  one  of  my 
people  to  observe  it.    Having  pleniy  of 
lime,  I  immediately  ordered  it  in  flour  to 
be  strewed  along  those  ranks  which  were 
not  begun.    This  destroyed  them  in  vast 
numbers,   and  secured  the  remainder. 
Another  time,  having  had  two  succeeding 
on  four  acres  of  land,  1  considered 
it  imprudent  to  venture  another.  How- 
ever, as  the  land  after  this  appeared  so 
clean  and  rich,  I  again  ventured,  but  soon 
bund  my  error.    On  examining  the  roots 
(for  after  it  had  begun  to  vegetate  strong, 
it  was  observed  to  decay  and  wither)  I 
found  thousands  of  the  wire  worm  at 
them,  entwined  in  every  root.    I  imme- 
diately strewed  lime,  (four  loads  of  six 
quarters  each,  on   the  four  acres)  and 
harrowed  it ;  when  rain  coming  on  *oon 
fter,  washed  it  in,  and  destroyed  them 


all,  and  gave  me  an  extraordinary  crop ; 
but  the  first  sown  side  of  the  field,  where 
they  had  begun,  never  quite  recovered  like 
the  rest.  And  I  am  fully  satisfied,  that  when 
the  grub  is  seen  in  wheat,  &c.  the  same 
treatment  (if  the  weather  suited)  would 
destroy  them  all,  as  well  as  change  the 
nature  of  the  land.  1  need  not  enter  on 
the  wide  and  extensive  field  of  observa- 
tions on  the  causes  of  weeds,  grubs,  Sec. 
(which  so  often  counteract  the  labours  of 
the  husbandman)  that  occur  so  dioerent- 
ly  in  different  seasons,  and  after  different 
treatment  and  improper  crops— further  to 
observe,  that  when  your  land  has  not  a 
proper  change,  then  it  is  that  these  are 
experienced  in  a  more  destructive  de- 
gree. , 

Further,  it  is  in  vain  to  expect  a  goon 
crop  of  woad,  of  a  good  quality,  from 
poor  and  shallow  land.  The  difference 
of  produce  and  its  value  is  so  gire  -  I  *t 
no  one  of  any  experience  will  wast .  his 
labour  and  attention  on  such  lands,  upon 
so  uncertain  a  produce.  Warm  and  moist 
4  E 


WOA 


WOA 


seasons  increase  the  quantity  every  where, 
but  they  can  never  give  the  principle 
which  only  good  laud  affords. 

In  very  wet  seasons,  woad  from  poor 
land  is  of  very  little  value.  I  once  had 
occasion  to  purchase  at  such  a  time,  and 
found  that  there  was  no  possibility  of  re- 
gulating my  vats  in  their  fermentation  ; 
and  1  was  under  the  necessity  of  making 
every  possible  effort  to  obtain  some  that 
was  the  produce  of  a  more  congenial  sea- 
son. I  succeeded  at  last;  but  1  kept  the 
other,  three  and  tour  years,  when  I  found 
it  more  steady  in  its  fermentation  ;  biu 
still  it  required  a  double  quantity,  and 
even  then  its  effects  was  not  like  that  from 
good  woad. 

The  leaves  of  woad  on  good  land,  in  a 
good  season,  grow  very  large  and  long, 
and  when  they  are  ripe  show  near  their 
end  a  brownish  spot,  inclining  to  a  pur- 
ple, towards  its  centre,  while  other  parts 
of  the  lea\es  appear  green,  but  just  be- 
ginning to  turn  of  a  more  yellowing  shade; 
and  then  they  must  be  gathered,  or  they 
will  be  injured. 

Woad  is  to  be  gathered  from  twice  to 
four,  and  even  five  times  in  the  season,  as 
I  once  experienced,  (It  was  an  early  and 
a  late  season)  and  for  the  next  spring  1 
saved  an  acre  for  seed,  of  which  I  had  a 
fair  crop.  I  picked  the  young  seedling 
sprouts  off  the  rest,  and  mixed  with  my 
first  gathering  of  what  was  newly  sown ; 
this  was  very  good.  During  one  season 
I  let  these  shoots  grow  too  long ;  the  con- 
sequence was,  that  the  fibrous  parts  be- 
came like  so  many  sticks,  and  afforded 
no  saponaceous  juices.  When  you  de- 
sign to  plant  woad,  on  the  same  land  the 
second  season,  it  should  be  as  soon  as 
your  last  gathering  (before  winter  is  l\- 
nished)  be  ploughed  ;  that  is,  as  soon  as 
the  weather  will  permit,  and  in  deep  fur- 
rows or  ridges,  to  expose  and  ameliorate 
it  by  the  vegetative  salts  that  exist  in  the 
atmosphere,  and  by  frost  and  snow.  This, 
in  some  seasons,  has  partly  the  effect  of  a 
change  of  produce  ;  but  if  intended  for 
wheat,  the  last  gathering  should  not  be 
later  than  September. 

The  land,  after  woad,  is  always  clean, 
and  the  nature  of  the  soil  appears  to  be 
greatly  changed  in  favour  of  the  wheat 
crop :  for  I  have  always  experienced 
abundant  increase  of  produce  after  woad, 
and  observed  that  it  held  on  for  some 
time,  if  proper  changes  were  attended  to 
and  good  husbandry.  Keeping  land  clean 
from  weeds,  certainly  produces  an  in- 
crease of  corn  ;  but  in  the  hoeing  and  ga- 
thering woad,  (for  hoeing  and  earthing  up 
the  plants  of  en  renders  them  abundantly 
more  prolific,  even  if  there  are  no  weeds) 


many  nests  of  animaculx  are  destroyedt 

as  well  as  grubs  and  insects,  which  are 
deal  ructive  to  vegetation. 

Woad  when  gathered,  is  carried  to  the 
mill  and  ground. 

These  nulls  grind  or  cut  the  leaves 
small,  and  then  they  are  cast  into  heaps, 
where  they  ferment,  and  gain  an  adhesive 
consistence  ;  they  are  then  formed  into 
bails,  as  compact  as  possible,  and  placed 
on  hurdles,  lying  horizontally  in  a  shed, 
one  over  the  other,  with  room  for  air  be- 
tween, to  receive  from  the  atmospheric 
air,  a  principle  which  is  said  to  improve 
them  as  a  dye,  as  well  as  to  dry  them  to  a 
degree  proper  for  being-  fermented  ;  but 
in  summer  these  balls  are  apt  to  crack  in 
drying,  and  become  fly-blown,  when  thou- 
sands of  a  peculiar  maggot  generate,  and 
eat,  or  destroy  all  that  is  useful  to  the  dy- 
er. Therefore  they  require  attention  as 
soon  as  any  are  observed  to  crack,  to  look 
them  all  over  well,  close  them  again,  so 
as  to  lvnderthem  as  compact  and  solid  as 
possible ;  and  if  the  maggot  or  worm  has 
already  generated,  some  fine  flour  lime 
strewed  over  it  wili  destroy  them,  and  be 
of  much  service  in  the  fermentation. 
These  balls,  if  properly  preserved,  will  be 
very  heavy;  but  it  worm-eaten,  they  will 
he  very  light,  and  of  little  value.  They 
are  then  to  be  replaced  on  the  hurdles, 
and  turned,  not  being  suffered  to  touch 
each  other,  until  a  month  or  more  after  the 
whole  that  is  intended  for  one  fermenting 
couch,  is  gathered  in,  ground  and  balied, 
and  often,  until  the  hot  weather  of  sum- 
mer is  past,  to  render  the  offensive  opera- 
tion of  turning  it,  less  disagreeable,  and 
not  so  apt  to  overheat ;  and  though  tem- 
perature Herein  is  necessary,  yet  a  certain 
degree  of  heat  must  be  attained,  before  it 
is  in  a  proper  condition  for  the  dyer's  use. 
This  is  easily  distinguished  by  a  changt  of 
smell — from  that  which  is  most  putrid, 
and  offensive,  to  one  which  is  morea14.ee- 
able  and  sweet, (it  I  may  be  allowed  the 
term)  for  few  people  at  first,  either  can 
approve  of  the  smell  of  woad,  or  a  woad 
vat ;  though,  when  in  condition,  they  be- 
come quite  agreeable  to  those  whose  bu- 
siness it  is  to  attend  them.  Woad  is  in 
this  state  of  fermentation,  more  or  less 
time,  according  to  the  season  and  the  de- 
gree of  heat  it  is  suffered  to  attain,  whe- 
ther at  an  early  period,  or  according  to 
the  opinion  of  those  who  attend  the  pro- 
cess ;  but  the  best  woad  is  produced  from 
a  heat  temperately  brought  forward  in 
the  couch  until  at  maturitv,  and  turned, 
(on  every  occasion  necessary)  which  a 
proper  degree  of  attention  will  soon  dis- 
cover. 

These  balls,  when  dry,  are  very  hair 


WOA 


VfOA 


and  compact,  and  require  to  be  broken 
wiili  a  mallet,  and  put  into  a  heap,  and 
Watered  to  a  due  degree,  only  sufficient 
to  promote  fermentation,  but  not  by  too 
much  moisture,  which  would  retard  it ; 
and  here  is  a  crisis  necessary  to  be  at- 
tended to.  When  the  couch  has  attained 
its  due  point,  it  is  opened,  spread,  and 
turned,  until  regularly  cooled,  and  then 
it  is  considered  in  condition  tor  sale  ;  but 
the  immediate  use  of  woad,  new  from  the 
couch,  is  not  advised  by  dyers  who  are 
experienced ;  for  new  woad  is  not  so  re- 
gular in  its  fermentation  in  the  blue  vat 
This  is  the  common  process.  Woad  of- 
tentimes is  spoiled  herein,  by  people  who 
know  nothing  of  the  principles  of  its  dye, 
following-  only  their  accustomed  process 
of  preparing  it;  and  hence  the  difference 
in  its  quality  is  as  often  seen,  as  it  is  m 
the  real  richness  or  poverty  of  the  leaves, 
from  the  quality  of  the  land.  The  process 
for  preparing  woad  which  I  have  followed, 
and  which  1  consider  beyond  all  compari- 
son best,  is  as  follows : 

Gather  the  leaves,  put  them  to  dry,  and 
turn  them,  so  as  not  to  let  them  heat,  and 
so  be  reduced  to  a  paste  ;  which,  in  fine 
weather,  children  can  do.  In  v/et  wea- 
ther, my  method  was  to  carry  them  to  my 
stove,  and  when  I  had  got  a  quantity  suf- 
ficiently dry,  1  proceeded  to  the  couch, 
and  there  put  them  in  a  lar^e  heap; 
where,  if  not  too  dry,  they  would  soon  be- 
gin to  ferment  and  heat.  If  too  wet,  they 
would  rot,  but  not  properly  ferment,  nor 
readily  become  in  condition  for  the  dyer. 
These  leaves  not  having  been  ground,  nor 
placed  in  balls  on  the  hurdles,  their  fer- 
menting quality  was  more  active,  and  re- 
quired more  attention  ;  and  also  the  ap- 
plication of  lime  occasionally  to  regulate 
the  process  with  the  same  kind  of  judg- 
ment as  used  in  the  blue  dying  woad  vat. 
When  the  heat  increases  too  rapidly,  turn- 
ing is  indespensably  necessary,  and  the  ap- 
plication of  very  fine  flour  lime,  regularly 
strewed  over  every  laying  of  them  ;  or,  if 
the  couch  is  getting  too  dry,  lime-water, 
instead  of  common  water,  applied  by  a 
gardener's  watering-pot,  may  have  an 
equal  effect,  without  loading  the  woad 
with  the  gross  matter  of  the  lime ;  though 
I  conceive  that  the  gross  dry  flour  lime, 
and  the  oxygen  in  the  air,  will  furnish 
more  carbonic  acid  gas  to  the  woad,  and 
retain  such  principles  as  are  essential,  to  a 
better  effect.  For  I  have  experienced, 
that  woad  which  requires  the  most  lime 
to  preserve  a  temperate  degree  of  fermen- 
tation, and  takes  the  most  time,  is  best;  so 
that  at  length  it  comes  to  that  heat  which 
is  indispensably  to  the  production  of  good 
woad. 


In  this  couch  it  is  always  particularly 

necessary  to  secure  the  surface  as  soon 
as  the  leaves  begin  to  be  reduced  to  a 
paste,  by  rendering  it  as  smooth  as  possi- 
ble, and  free  from  cracks.  This  prevents 
the  escape  of  much  carbonic  acid  gas, 
(which  is  furnished  by  the  lime  and  the 
fermentation)  and  also"  preserves  it  from 
the  fly,  maggots,  and  worms,  which  often 
are  seen  in  those  parts  where  the  heat  is 
not  so  great,  or  the  lime  in  sufficient 
quantity  to  destroy  them.  It  is  surprising 
to  observe  what  a  degree  of  heat  they  will 
bear.  This  attention  to  rendering  the 
surface  of  the  couch  even  and  compact,  is 
equally  necessary  in  either  process,  and  to 
turning  the  woad  exactly  as  a  dung-heap, 
digging  perpendicularly  to  the  bottom. 
The  couching-house  should  have  an  even 
floor,  of  stone  or  brick,  and  the  walls  the 
same ;  and  every  part  of  the  couch  of 
woad  should  be  beaten  with  the  shovel, 
and  trodden,  to  render  it  as  compact  as 
possible. 

The  grower  of  woad  should  erect  a 
long  shed  in  the  centre  of  his  land,  facing 
the  south,  the  ground  lying  on  a  descent, 
so  as  to  admit  the  sun  to  the  back  part ; 
and  here  the  woad  should  be  put  down 
as  gathered,  and  spread  thin  at  one  end, 
keeping  children  to  turn  it  towards  the 
other  end.  In  the  course  of  a  week,  eve- 
ry days  gathering  will  be  dry  for  the 
couch,  which  should  be  at  the  other  end ; 
therefore  it  will  be  necessary  to  calculate 
how  long  the  shed  should  be ;  but  this 
can  be  erected  as  you  gather,  and  then  it 
will  soon  be  known. 

Good  woad,  such  as  the  richest  land 
produces,  if  properly  prepared,  will  be  of 
a  blackish  green,  and  mouldy  ;  and  when 
small  lumps  are  pulled  asunder,  the  frac- 
ture and  fibres  are  brown  ;  and  these  fi- 
bres will  draw  apart  like  small  threads, 
and  the  more  stringy  they  are,  and  the 
darker  the  external  appearance,  and  on 
the  green  hue,  the  better  the  woad;  but 
poor  land  produces  it  of  a  light  brownish 
green.  The  fibres  only  serve  to  show  that 
it  has  not  suffered  by  putrefaction. 

For  the  use  of  the  dyer,  the  balls  re- 
quire a  farther  preparation.  They  are 
beaten  with  wooden  mallets,  on  a  brick 
or  stone  floor,  into  a  gross  powder,  which 
is  heaped  up  in  the  middle  of  the  room, 
to  the  height  of  four  feet,  a  space  being 
left  for  passing  round  the  sides.  The 
powder  moistened  with  water,  ferments, 
grows  hot,  and  throws  out  a  thick  fetid 
fume.  It  is  shovelled  backward  and  for- 
ward, and  moistened  everyday  tor  tw  elve 
days ;  after  which  it  is  stirred  less  fre- 
quently, without  watering,  and  at  length 
.made  into  a  heap  for  the  dyer. 


AVOO 


AVOO 


WOLFRAM.    See  Tukgstex. 

WOO D,  staining  of.    See  Dyeing. 

W"OOD, preservation  of. 

Various  means  have  been  used,  in  or- 
der to  preserve  wood  work  from  decay. 
Dr.  Parry  has  written  an  ingenious  essay 
on  this  subject,  which  may  be  found  co- 
pied into  Mease's  Archives  of"  Useful 
Knowledge, and  Coxe's  Kmporium.  It  is 
not  our  intention,  to  notice  the  causes 
which  produce  the  decomposition  of  ve- 
getable substance,  and  undoubtedly  air 
and  water  are  the  primary  ones,  we  shail 
state  in  general  terms,  the  means  which 
have  been  adopted,  in  order  to  prevent 
their  access,  tor  the  preservation  of  the 
wood. 

1.  If  paint  be  applied  in  several  succes- 
sive coats,  it  will  have  the  effect  of  pre- 
serving the  wood  thus  coated  for  years. 
In  the  use  of  paint,  the  oil  as  well  as  the 
pigment,  tends  to  produce  the  effect. 

2  Oils.  Drying  oil  and  other  unctu- 
ous substances.  These  prevent  the  ac- 
cess of  air  and  moisture  very  considera- 
bly. 

3.  The  mixture  of  fine  sand  with  white 
paint-  This  is  said  to  be  a  good  compo- 
sition. 

4.  For  water-shoots  in  particular,  rub- 
Ling  the  surface  with  linseed  oil,  and 
pledging  it  all  over  with  a  thick  layer  of 
charcoal  finely  powdered,  and  contained 
in  a  muslin  bag.  After  the  oil  is  dry,  rub 
off  the  superfluous  coal,  and  apply  a  coat 
of  white  lead  paint.  In  the  piace  of  pow- 
dered charcoal,  lamp-black  may  be  us- 
ed. 

5.  Pitch,  if  applied  hot,  makes  a  good 
varnish  or  covering.  Jts  mixture  with 
Spanish  brown,  is  said  to  answer  a  better 
purpose.  The  pitch,  however,  will  be 
apt  to  run,  if  the  wood  work  be  exposed 
to  the  sun.  The  ends  of  posts,  which  are 
put  in  the  ground,  will  be  preserved  by 
this  substance. 

6.  A  mixture  of  animal  oils  with  bees 
wax,  resin,  and  brimstone — melt  twelve 
ounces  of  resin  in  an  iron  pot  or  kettle  ; 
add  three  gallons  of  train  oil,  and  three 
or  four  rolls  of  brimstone  melted  and 
become  thin,  add  as  much  Spanish  brown, 
or  red  or  yellow  ochre,  or  any  colour  you 
want,  first  ground  fine  with  some  of  the 
oil,  as  will  give  the  whole  as  deep  a  shade 
as  you  like.  Then  lay  it  on  with  a  brush 
as  hot,  and  as  thin  as  you  can.  Some 
da}  s  after  the  first  coat  is  dried,  give  it  a 
second.  It  will  preserve  plank  forages 
and  keep  the  weather  from  driving 
through  brick-work. 

These  compositions  are  equally  effica- 


cious, in  keeping  iron  from  decay  by  rust* 
ing.  They  might  also  be  very  advanta- 
geously employed,  in  rendering  water- 
tight, the  plaister  which  is  used,  to  case 
the  outside  of  the  arches  of  vaults,  un- 
sheltered by  roofs,  provided  the  morrar 
were  made  perfectly  dry,  and  the  cover* 
ing  of  the  arch  brought  up  to  an  angle, 
instead  of  making  it  follow  the  form  of 
the  arch  in  an  elipse  or  the  segment  of  a 
circle. 

Dr.  Parry  has  given  the  following  re- 
ceipt for  the  preservation  of  wood. 

l  ake  twelve  ounces  of  rosin,  and  eight 
ounces  of  roll  brimstone,  each  coarsely 
powdered,  and  three  gallons  of  train-oil. 
Heat  them  slowly,  gradually  adding  four 
ounces  of  bees  wax,  cut  into  small  bits. 
Frequently  stir  the  liquor,  which,  as  soon 
as  the  solid  ingredients  are  dissolved, 
will  be  fit  for  use.  What  remains  unused, 
will  become  solid  on  cooling,  and  may  be 
remelted,  on  subsequent  occasions 

If  the  addition  of  charcoal,  powder,  or 
siliceous  sand,  contributes  to  the  durabi- 
lity of  drying  oil,  it  may  probably  have  a 
similar  effect  on  the  composition  ;  but 
whether  it  may  be  best  to  mix  them  with 
the  ingredients,  or  apply  them  afterwards, 
we  cannot  from  experience  tell.  In  the 
latter  case,  the  powder  should  be  sifted 
on,  while  the  first  coat  of  the  composition 
is  still  hot ;  and  after  some  days,  when 
that  is  dry,  should  have  a  brush  gently 
passed  over  it,  in  order  to  remove  all  the 
panicles  which  do  not  adhere;  after  which 
other  coats  of  the  composition  may  be  ap- 
plied, as  before  directed. 

7.  The  best  preserver  of  wood  is  char- 
coal. For  this  purpose,  it  was  the  cus- 
tom, and  is  now  sometimes  adopted,  to 
char  or  carbonize  the  ends  of  posts,  which 
are  planted  in  the  ground,  to  preserve 
them.  The  indistructability  of  charcoal, 
is  well  known. 

8.  Dr.  Lewis  advises  all  wood,  that  is 
exposed  to  the  inclemency  of  the  weather, 
to  be  coated  with  a  preparation  of  pulve- 
rized pit-coal,  and  melted  tar,  reduced 
to  the  consistence  of  paint,  which  he  has 
found  very  efficacious.  In  those  cases, 
however,  where  piles  or  other  masses  of 
timber,  are  subject  to  the  action  of  water, 
the  most  simple  mode  of  preserving  it,  is 
that  employed  in  the  Bermuda  Islands,and 
other  parts  of  America.  This  plan  has 
been  stated,  to  <witt  by  applying  whale  or 
other  animal  oil. 

9.  To  preserve  boards,  scantling,  &c. 
the  following  method  is  used.  Lay  the 
boards  in  a  bed  of  sand,  (contained  in  a 
case  or  shell  of  brick-work,)  and  heated 
by  means  of  a  furnace,  built  beneath.  As 


woo 


woo 


soon  as  the  wood  becomes  hot,  the  sap 
exudes,  and  is  imbibed  by  the  sand ;  in 
consequence  of  winch,  the  quality  of  the 
timber  is  greatly  improved.  The  boards 
will  then  last  a  considerable  time. 

10  In  March  1778,  a  patent  was  grant- 
ed to  Mr.  Humphrey  Jackson,  for  his  me- 
thod of  beautifying-,  and  preserving'  the 
colour  of  every  kind  of  wood,  by  means  of 
a  stain,  varnish,  and  powder  He  directs 
the  substance  first  to  be  polished  with  the 
following  composition. 

Take  pumice-stone  and  burnt  alum, 
of  each  equal  parts  ;  lapis  caiaminaris, 
and  green  vitriol  calcined  to  redness,  of 
each  half ;  let  the  whole  be  reduced 
to  a  fine  powder,  and  rubbed  with  a 
woollen  cloth  on  the  wood,  till  it  acquire 
a  fine  polish  ;  the  stain  must  now  be  pre- 
pared as  follows. 

Let  six  pounds  of  stick-lac,  be  boiled 
in  three  gallons  of  water,  till  the  colour 
be  extracted,  when  the  liquor  ought  to 
be  strained ;  half  a  pound  of  madder-root, 
is  also  to  be  boiled  in  three  quarts  of  wa- 
ter :  next,  half  a  pound  of  cochineal,  a 
similar  quantity  of  kermes,  and  four  oun- 
ces of  clean  scarlet-rags,  are  to  be  digest- 
ed in  a  glass  vessel,  containing  one  gallon 
of  spirit  of  wine,  and  a  solution  of  two 
ounces  of  pearl-ash,  in  half  a  pint  of  wa- 
ter, till  all  the  tinging  matter  be  combin- 
ed with  the  liquor.  After  straining  it,  the 
decoction  of  stick-lac  must  be  added,  and 
a  sufficient  quantity  of  aqua-fortis,  be  mix- 
ed with  the  whole,  to  impart  a  proper  red 
colour  ;  when  the  compound  may  be  laid 
on  with  a  brush.  In  order  to  prepare  the 
varnish,  the  patentee  directs  one  pound 
of  clear  white  amber,  half  a  pound  of  co- 
pal, a  similar  quantity  of  spirit  of  turpen- 
tine, as  well  as  of  the  oils  of  rosemary, 
and  lavender  ;  and  six  pounds  of  nut-oil, 
to  be  digested  in  a  sand-heat,  till  the  oils 
acquire  the  consistence  of  syrup  :  the  li- 
quor is  now  to  be  strained  for  use  ;  and, 
when  the  varnish  becomes  clear,  it  must 
be  applied  to  the  stained  wood,  with  a 
painter's  brush  ;  after  which  it  should  be 
suffered  to  dry. 

WOOL.  The  late  importation  of  Spa- 
nish sheep  into  the  United  States,  under 
the  general  name  of  Merinos,  affording 
reasonable  grounds  for  the  belief,  that  the 
article  of  wool,  so  necessary  to  the  health 
and  comfort  of  man,  will  become  a  staple 
of  our  country,  we  think  proper  under 
this  head  to  introduce  some  remarks  upon 
this  important  article,  which  we  hope  and 
believe,  will  be  found  of  importance,  to 
all  who  are  concerned  in  the  various  bran- 
ches of  manufacture,  to  which  wool  is 
appropriated.  And  first,  from  "Nichol- 
son's Chemical  Dictionary,"  we.  have  ex- 


tracted the  following  short,  but  pertinent 

treatise. 

The  principal  differences  in  wool,  con- 
sists in  the  length  and  fineness  of  its  fila- 
ments. That  which  has  the  finest  fila- 
ments, is  reserved  for  fine  cloths.  The 
most  beautiful  wool,  is  brought  to  us, 
from  Spain.  It  is  said  that  the  highland 
wool  of  Scotland,  is  equal  in  quality  to 
this.  Mr.  d'Aubenton  has  shown,  that 
ii  may  be  produced  in  France,  of  a  qua- 
lity not  inferior  to  that  of  Spain  ;  by  fold- 
ing the  sheep  through  the  whole  year, 
and  choosing'  the  rams  with  care.  Lately 
the  breed  of  Merino,  or  fine  woolled  Spa- 
nish sheep,  has  been  introduced  into  this 
country  by  his  majesty,  and  found  to  re- 
tain the  excellent  qualities  of  the  fleece. 
It  has  likewise  been  crossed  with  our  own 
breeds  with  advantage,  so  that  we  may 
hope  to  become  independent  of  Spain  for 
fine  wool. 

Simple  inspection  may  easily  lead  to  er- 
ror, respecting  the  fineness  of  wool,  which 
it  is  important  the  manufacturer  should 
know  with  accuracy ;  and  Mr.  d*Auben- 
ton  has  proposed  a  method,  of  attaining 
this  accuracy,  by  employing  a  microme- 
ter, tor  comparing,  by  means  of  a  micros- 
cope, the  fineness  of  the  wool  to  be  exa- 
mined, with  that  of  other  wools,  chosen 
as  standards. 

Though  the  long  wool  is  not  so  fine  as 
the  Spanish,  and  cannot  be  employed  for 
fine  cloths,  it  is  still  very  useful  for  a  va- 
riety of  fabrics  ;  and  as  the  sheep  which 
produce  it,  have  much  larger  fleeces,  the 
profit  they  bring,  is  not  inferior  to  that 
of  the  fine  woolled  sheep ;  besides,  the 
cloths  made  of  their  wool,  being  cheaper, 
have  a  much  more  extensive  sale.  The 
prosperous  state  of  the  woollen  manufac- 
tures of  England,  is  partly  owing  to  our 
abundance  of  this  wool.  But  the  breed 
of  sheep,  which  produces  one  or  the  other 
kind  of  wool,  is  connected  with  the  na- 
ture of  their  pasture,  which  ought  to  de- 
termine us  in  the  choice  of  them. 

Wool  is  naturally  covered  with  a  kind 
of  grease,  which  preserves  it  from  moths. 
Reaumur  has  observed,  that  a  stuff  may 
be  preserved  from  these  insects,  by  rub- 
bing it  with  greasy  wool.  Hence  wool 
is  not  scoured,  till  it  is  about  to  be  dyed 
or  spun. 

In  order  to  scour  wool,it  is  put  for  about 
a  quarter  of  an  hour  into  a  kettle,  contain- 
ing a  sufficient  quantity  of  water,  mixed 
with  a  fourth  of  putrid  urine,  heated  to 
such  a  degree,  as  the  hand  can  just  bear, 
and  it  is  stirred  from  time  to  time  with 
sticks ;  it  is  then  taken  out  and  put  to 
drain  :  it  is  next  carried  in  a  large  basket 
to  a  stream  of  running  water,  where  it  is 


woo 


woo 


moved  about,  till  the  grease  is  entirely 

separated,  and  no  longer  renders  the  wa- 
ter turbid  ;  it  is  then  taken  out  and  left 
to  drain.  It  sometimes  loses  in  this  ope- 
ration, more  than  a  third  of  its  w  eight. — 
The  scouring  should  be  carefully  per- 
formed, because  the  wool  is  thereby  bet- 
ter f.Hcd  to  receive  the  dye. 

The  ammonia  or  volatile  alkali,  formed 
in  putrid  urine,  lias  been  supposed  to  unite 
with  the  grease,  producing-  a  kind  of  soap, 
which  is  soluble  in  water.  But  Yauque- 
lin  thinks,  if  any  thing  in  the  urine  have 
an  effect  upon  the  grease  or  3  o.k,  as  the 
French  call  it,  it  is  the  uree.  Fresh  urine 
will  not  answer,  on  account  of  the  acid 
it  contains.  According  to  him,  soapsuds 
are  the  oest  menstruum  for  scouring  wool, 
after  simple  water  has  washed  off  all  it 
can  remove.  He  observes  too,  that  wool 
kept  too  long  in  its  grease,  swells,  splits, 
and  is  weakened 

The  wool  is  dyed  in  the  fleece,  or  be- 
fore it  is  spun,  chiefly  when  it  is  intended 
to  form  cloths  of  mixed  colours  ;  or  else 
it  is  dyed  after  being  spun,  and  it  is  then 
intended  principally  for  tapestry  ;  but  it 
is  sometimes  dyed,  after  having  been 
Wrought  into  cloth. 

When  wool  is  dyed  in  the  fleece,  its 
filaments  being  separate,  absorb  a  larger 
quantity  of  the  colouring  panicles,  than 
when  it  is  spun ;  for  th<  same  reason 
woollen  yarn,  takes  up  more  than  cloth  ; 
but  cloths  themselves  vary  considerably 
in  this  respect,  according  to  their  degree 
of  fineness,  or  the  closeness  of  their  tex- 
ture :  besides,  the  variety  in  their  dimen- 
sions, the  different  qualities  of  the  ingre- 
dients employed  in  dye;  ng,  and  a  differ- 
ence of  circumstances  hi  the  process,  pre- 
vent us  from  relying  upon  the  precise 
quantities  we  find  recommended  tor  the 
processes  described.  This  consideration 
may  be  extended  to  all  dyes. 

For  most  colours,  wool  requires  to  be 
prepared  by  a  bath,  in  which  it  is  boiled 
with  saline  substances,  principally  with 
alum  and  tartar  :  but  there  are  some  dyes 
for  which  the  wool  does  not  require  such 
a  preparation  ;  then  it  must  be  well  wash- 
ed in  warm  water,  or  wrung  out,  or  left  to 
drain.  This  is  a  general  rule,  which 
should  be  observed,  with  respect  to  all 
the  substances  intended  to  be  dyed,  in 
order  that  the  colour  may  penetrate  them 
more  easily,  and  be  distributed  more  uni- 
formly. 

Mr.  Monge  has  explained  the  opera- 
tion of  felting,  and  the  effects  of  fulling, 
by  the  exu  rnal  conformation  of  the  wool 
and  liar  of  animals.  He  has  made  some 
curious  observations  on  this  subject,  of 
which  the  following  arc  the  chief: 


Nothing  particular  can  be  discovered, 
by  means  of  the  microscope,  in  the  fila- 
ments of  wool,  or  in  the  hair  of  animals  ; 
yet  the  surfaces  of  these  bodies  are  not 
smooth  :  they  must  be  formed,  either  of 
small  laminae,  placed  over  each  other  in  a 
slanting  direction,  from  the  root  towards 
the  point,  like  the  scales  of  fish,  which 
cover  each  other,  from  the  head  of  the 
animal  to  the  tail,  or  more  probably,  per- 
haps, of  zones,  placed  one  upon  another, 
as  we  see  in  the  horns  of  animals. 

If  a  hair  be  laid  hold  off  by  the  root,  in 
one  hand,  and  drawn  between  the  fingers 
of  the  other,  from  the  root  towards  the 
point,  scarce  any  friction  or  resistance  is 
perceived,  and  no  noise  is  heard ;  but  if, 

aspiDg  it  by  the  point,  it  is  passed  in 
the  same  manner  between  the  fingers  of 
the  other  hand,  from  the  point  towards 
the  root,  a  resistance  is  felt,  which  did 
not  take  place  in  the  former  place,  and  a 
tremulous  motion  is  perceptible  to  the 
touch,  and  a  noise  sensible  to  the  ear. 

We  perceive  then,  that  the  texture  of 
the  surface  of  hair,  is  not  the  same  from 
tiie  root  towards  the  point,  as  it  is  from 
the.  point  towards  the  root,  and  that  a 
hair  when  pressed,  must  meet  with  great- 
er resistance,  in  sliding  or  moving  to- 
wards the  point  than  towards  the  root ; 
but  asit  is  tnis  texture  itself,  which  forms 
the  principal  subject  of  Mr.  Monge's  me- 
moir, it  is  necessary  to  confirm  it  by  some 
farther  observations. 

11,  after  having  laid  hold  of  a  hair  be- 
tween the  thumb  and  fore -finger,  we  rub 
them  against  each  other  in  the  longitudi- 
nal direction  of  the  hair,  it  acquires  a  pro- 
gressive motion,  in  that  direction  towards 
the  root.  This  effect  depends  neither  on 
the  nature  of  the  skin  of  the  finger,  nor  on 
its  texture  ;  for  if  the  hair  be  toi  ned,  so 
that  the  point  shall  be  placed,  where  die 
root,  was  before,  its  motion  will  now  be  in 
an  opposite  direction,  that  is,  it  will  still 
be  towards  the  root. 

These  observations.to  which  Mr.Monge 
adds  some  others,  are  related  of  human 
hair,  taken  as  an  example  ;  but  they  are 
equally  applicable  to  the  filaments  of  wool, 
to  horse-hair,  and  to  that  of  animals  in  ge- 
neral. The  surface  of  all  these  bodies, 
then  is  formed  of  rigid  laminae,  laid  upon 
each  other  like  tiles,  from  the  root  to  the 
point,  which  allow  a  prog,  essive  motion  in 
the  direction  of  the  root,  but  oppose  one 
in  the  direction  of  the  point. 

This  structure  is  the  principal  cause  of 
the  disposition  to  felting,  which  the  hair 
of  animals  generally  possesses  :  the  hatter, 
by  striking  the  flocculi  of  woof  with  the 
string  of  his  bow,  detaches  and  disperses 
in  the  air  each  of  the  filaments  separately ; 


woo 


woo 


these  fall  back  one  upon  another  in  all  | 
directions  on  the  table,  where  they  form  | 
a  layer  of  a  certain  thickness  :  the  work- 
man then  covers  them  with  a  cloth  (I  sup- 
pose linen,)  upon  which  he  presses  on  all 
parts,  with  his  hands  extended. 

The  pressure  brings  the  filaments  of 
wool  nearer  to  each  other,  and  multiplies 
the  points  of  contact ;  the  agitation  gives 
each  of*  them  a  progressive  motion  in  the 
direction  of  its  root,  by  means  of  which 
they  entangle  each  other;  and  the  laminx 
of  each  filament,  taking  hold  of  those  of 
the  other  filaments,  which  are  in  an  oppo- 
site direction,  the  whole  is  retained  in  the 
state  of  close  contexture,  which  it  had  ac- 
quired by  the  pressure. 

In  proportion  as  the  texture  becomes 
closer,  the  pressure  of  the  hands  ought  to 
be  increased,  both  in  order  to  make  it 
still  more  compact,  and  to  keep  up  the 
progressive  motion,  and  intermixture  of 
the  filaments,  which  now  meet  with  great- 
er resistance  :  but  during  the  whole  of 
this  operation,  the  filaments  of  wool  lay 
hold  of  each  other  only,  and  not  of  the 
cloth,  the  fibres  of  which,  as  has  been 
already  observed,  are  smooth,  and  have 
not  the  same  properties  in  this  respect. 

The  aptitude  for  felting  in  wool  and 
hair,does  not  depend  entirely  on  the  struc- 
ture of  their  suiface;  it  is  not  enough, 
that  each  filament  should  have  a  progres- 
sive motion,  in  the  direction  of  its  root ; 
nor  that  the  inclined  laminze,  by  laying 
hold  of  each  other,  should  retain  the  con- 
texture in  the  state,  to  which  it  has  been 
reduced  by  compression  :  it  is  also  neces- 
sary, that  the  filaments  should  not  be 
straight  like  needles  ;  for,  by  a  continu- 
ance of  the  motion  and  pressure,  each 
of  them  would  continue  its  course  pro- 
gressively, without  changing  its  direction, 
and  the  effect  of  the  operation  would  be 
to  remove  them  all  from  the  centre,  with- 
out producing  any  contexture.  It  is  there- 
fore necessary,  that  each  filament  should 
be  crooked,  so  that  the  extremity  nearest 
the  root,  should  be  so  disposed  to  change 
its  direction  continually,  to  entwine  itself 
round  fresh  filaments,  and  to  return  buck 
upon  itself,  if  it  should  be  so  determined 
by  any  change  in  the  position,  of  the  rest 
of  its  length. 

Wool  possessing  this  structure  natu- 
rally, is  peculiarly  fitted  for  this  kind  of 
work,  and  may  be  employed  in  it,  without 
being  subjected  to  any  previous  prepara- 
tion ;  but  the  furs  of  the  rabbits,  hares, 
and  beavers,  are  naturally  straight,  and 
cannot  be  employed  alone  forfeiting,  with- 
out having  undergone  a  previous  opera- 
tion, which  consists  in  rubbing  them,  be- 
fore they  are  stripped,  with  a  brush  moist- 


ened with  a  solution  of  mercury  in  nitrous 
acid  ;  this  liquor,  by  acting  only  on  one 
side  of  the  hairs,  changes  their  rectilinear 
direction,  and  communicates  to  them  that 
disposition  for  felting,  which  wool  natu- 
rally possesses. 

The  operation  of  fulling  woollen  stuffs, 
depends  on  the  same  property  as  felt- 
ing. 

The  asperity  of  the  surface  of  the  fila- 
ments of  wool,  and  their  disposition  to  ac- 
quire a  progressive  motion  in  the  direc- 
tion of  the  root,  form  an  obstacle  to  the 
spinning  of  wool,  and  the  working  it  into 
stuffs.  All  the  filaments  must  therefore, 
be  covered  with  a  coat  of  oil,  winch,  by 
filling  the  cavities,  renders  the  asperities 
less  sensible ;  just  as  a  coat  of  oil  renders 
a  fine  file  still  smoother.  When  the  piece 
of  stuff  is  wrought,  it  must  be  freed  from 
that  oil,  which  gives  it  a  disagreeable 
smell,  t  enders  it  dirty, and  would  prevent 
it  from  taking  the  colour  we  wish  to  dye 
it ;  for  this  purpose,  it  is  taken  to  the  full- 
ing-mill, where  it  is  beaten  with  large 
beetles  in  a  trough  of  water,  through 
which  some  clay  has  been  diffused.  The 
clay  uniting  with  the  oil,  renders  it  solu- 
ble in  the  water,  and  both  are  carried  off 
together,  by  fresh  -water  brought  thither 
by  the  machine  ;  and  after  sometime,  the 
stuff  is  found  clean  scoured.  See  Earth 
(Fuller's.) 

But  scouring  is  not  the  only  object  in 
fulling  ;  the  alternate  pressure  of  the  bee- 
tles on  the  stuff,  particularly  when  the 
scouring  is  advanced,  produces  an  effect 
analogous  to  that  of  the  pressure  of  the 
hatter's  hands  ;  the  filaments  of  wool, 
which  compose  a  thread  of  the  warp,  or 
of  the  woof  acquire  a  progressive  motion, 
insinuate  themselves  into  the  adjoining 
threads,  then  into  those  which  are  next, 
and  presently  all  the  threads,  both  of  the 
warp  and  woof,  are  felted  together.  The 
stuff  is  now  found  contracted  in  length 
and  breadth,  and  participates  both  uf  the 
nature  of  cloth,  and  of  felt ;  it  may  be  cut 
without  being  subject  to  ravel,  and  there 
is  no  necessity,  for  hemming  the  diffetent 
pieces  of  it  employed,  to  make  a  garment. 
If  it  be  common  woollen  stocking  web, 
the  stiches  are  now  no  longer  subject  to 
run,  when  one  of  them  happens  to  slip; 
finally,  the  threads  of  the  warp  and  the 
woof,  are  now  no  longer  so  well  defined, 
or  so  distinct  from  each  other ;  and  the 
stuff  being  also  thickened  forms  a  Warn- 
er clothing-. 

Berthollet  obtained  a  large  proportion 
of  acid  of  sugar,  by  abstraction  of  nitric 
acid  from  wool 

If  wool  be  bjiled  with  pure  weak  alkali, 
it  is  dissolved,  with  the  escape  of  ammo. 


woo 


woo 


nia,  and  forms  a  soap,  likely  to  be  of  use 
in  the  ai  ts.    See  Soap  of  Wool. 

Mr.  Tessier,  a  French  writer  of  great 
merit,  makes  the  following  observations 
on  the  fleeces  of  wool,  and  of  the  differ- 
ent modes  of  washing  them. 

Wool  should  be  kept  in  a  place,  which 
is  neither  damp  nor  dry  In  a  damp  place 
it  would  grow  heavier,  to  the  disadvan- 
tage of  the  purchaser  ;  in  too  dry  a  place, 
it  would  lose  pari  of  its  weight,  which 
would  be  unfavourable  to  the  vender. — 
To  keep  it  well,  it  should  be  placed  in  a 
lower  room,  that  is  exposed  to  the  north, 
and  cool,  three  or  four  feet  from  the 
ground,  and  not  touching  the  walls.  No 
dust  should  enter  this  place,  otherwise 
the  wool  must  be  covered  with  linen. 

Of  the  Fleeces  and  Wool. 

The  fleeces  of  merino  rarrs  which  come 
from  Spam,  weigh  at  most,  unwashed, 
tight  pounds,  and  those  of  the  ewes,  live 
pounds  ;  and  in  France  we  obtain  from 
rams  of  that  race,  as  much  as  18  pounds, 
and  from  ewes  as  much  as  12  pounds, 
this  is  the  maximum.  The  usual  weight 
for  ewes,  is  from  7  to  8  pounds,  and  for 
rams,  from  8  to  10  pounds. 

What  is  the  reason  of  the  difference, 
between  the  weight  of  the  fleeces  of  me- 
rinos, in  Spain  and  in  France  ?  It  is  he- 
cause  in  Spain,  sheep  live  only  upon  what 
they  find  m  the  fields;  sometimes  they 
find  very  little  there  :  besides,  as  they 
are  of  a  smaller  size,  they  must  carry  less 
wool.  In  France,  the  deficiency  of  pas- 
ture, is  always  amplv  supplied  in  the  sta- 
ble. 

The  weight  of  wool  does  not  depend 
upon  its  thickness  alone,  but  also  upon 
its  length  :  in  this  latter  respect,  we  have 
gained  much;  our  wool  has  become  more 
fit  for  the  manufacture  of  casimirs. 

All  parts  of  a  fleece  are  not  alike  ;  it 
may  be  distinguished  into  wool  of  four 
different  qualities :  the  first  grows  upon 
the  shoulders  and  the  back,  from  the  neck 
to  about  half  a  foot  from  the  tail,  includ- 
ing a  third  part  of  the  body  ;  the  second 
covers  the  sides,  and  extends  from  the 
thighs  to  the  shoulders,  approaching  to 
the  neck  ;  the  third  grows  about  the  neck, 
and  covers  the  buttocks ;  the  fourth  co- 
vers, 1.  from  the  tore  part  of  the  neck,  to 
the  extremities  of  the  feet,  comprehend- 
ing apart  of  the  shoulders,  2.  the  two 
hind-legs  to  the  hoofs:  in  Spain,  this 
fourth  sort  is  called  cayda,  and  in  Fi  ance 
basse  laine.  The  more  equal  in  quality, 
the  wool  is  on  all  parts  of  the  body,  the 
greater  is  the  value  of  the  animal,  which  j 


[carries  it.      See  Manufacture  of 

!  Cloth. 

\     Experiments  which  have  been  made  in 
'  the  garden  of  the  Museum  of  natural 
.  history,  by  covering  with  linen  cloth,  dur- 
;  ing  a  year,  the  bodies  of  some  wethers, 
have  proved  that  wool,  when  protected 
!  from  the  air,  grows  finer  and  whiter  :  the 
;  difference  is  very  sensible.    But  it  re- 
mains to  be  determined,  whether  the  ex- 
pense of  covering  them,  does  not  more 
than  counterbalance  the  increased  value 
of  the  wool ;  any  person  may  easily  make 
the  calculation. 

The  wool  of  dead  or  sick  sheep,  should 
be  put  by  itself,  as  being  less  fit  for  ma- 
nufacturing, than  that  of  healthy  animals. 
1  suspect  it  is  more  liable  to  be  attacked 
by  vermin  ;  Mr.  Hoard  has  proved  by  ex- 
periment, that  in  dyeing,  it  does  not  take 
colour  so  well.  Of  three  kinds  of  wool 
which  I  gave  him,  one  from  healthy  sheep, 
anol  her  from  sick  sheep,  and  a  third  from 
dead  sheep,  the  first  look  a  deep  dye 
from  the  different  colours  with  which  it 
was  tried  ;  the  second  took  them  faintly  ; 
and  the  third  more  faintly  still.  It  fol- 
lows, that  proprietors  of  sheep  should  be 
careful,  not  to  mix  these  different  kinds 
of  wool,  and  that  manufacturers,  would 
do  well  to  show  particular  favour,  to- 
wards those  who  do  not  deceive  them. — 
I  also  think,  that  the  wool  of  sheep  killed 
in  the  slaughter-houses,  which  is  taken 
ofl'  by  means  of  lime,  is  much  inferior  to 
that  of  sheep  shorn,  while  they  are  alive. 
It  wants  that  oily  matter,  which  nourishes 
it  during  the  animal's  life,  and  which  con- 
tinues in  the  wool,  if  it  be  shorn  while 
the  sheep  is  in  full  health  ;  which  is  not 
astonishing,  since  the  same  thing  may  be 
observed,  with  regard  to  hair.  Lime  also 
renders  the  wool  hard. 

With  a  view  of  obtaining  fleeces,  both 
fine  and  long,  sheep  at  liambouillet  have 
beeii suffered  to  go  without  shearing,  two, 
three, four  and  five  years.  These  animals 
bore  their  burden  without  appearing  to 
be  much  incommoded  by  it  ;  only  they 
could  not  get  up  again  if  they  happened 
to  fall  upon  their  sides,  especially  during 
the  third  year,  for  they  carried  a  weight 
of  from  24  to  30  pounds.  After  three 
years,  the  wool  began  to  come  out,  and 
its  quantity  continued  to  decrease  ;  none 
of  them  fell  sick,  after  the  fleeces  were 
taken  off.  The  manufactures,  every  year, 
purchase,  with  eagerness,  and  at  a  great 
price,  these  noble  fleeces;  it  is  not  yet 
known  to  what  use  they  apply  them.  I 
advise  proprietors  who  wish  to  try  this 
method,  to  do  it  with  wethers  rather  than 
ewes,  because  the  length  of  the  wool  is 


woo 


woo 


troublesome  to  ewes,  when  they  give 
suck. 

Daubenton,  in  order  to  distinguish  the 
different  degrees  of  fineness  in  wool, 
makes  use  of  a  micrometer.  But  this  in- 
strument, though  it  affords  the  surest 
method,  is  troublesome  for  farmers,  who 
do  not  know  how  to  make  use  of  it.  Ha- 
bit teaches  them  to  distinguish  the  differ- 
ent kinds  of  wool,  by  simply  comparing 
them  together,  or  by  laying  them  upon 
paper  or  black  cloth. 

Another  observation,  for  which  I  am  in- 
debted to  Mr.  Roard,  is  that  v/ool  of  dif- 
ferent breeds  does  not  all  take  dye  equal- 
ly well.  Merino  wool  takes  the  deepest 
colour. 

Wool  may  be  kept  longer  if  the  yoke 
remain  in  it,  than  if  it  be  washed ;  this 
oily  substance  keeps  off  a  long  time  the 
insects  which  are  apt  to  attack  it.  By- 
placing  it  in  the  manner  which  I  have  be- 
fore described,  it  will  be  still  less  exposed 
to  vermin. 

Wool  is  liable  to  be  destroyed  by  seve- 
ral kinds  of  moths  or  caterpillars  ;  (tinea 
pellionelLa,  tinea  topezella,  tinea  vestinella, 
tinea  sarcitella)  the  butterflies  which  pr  o- 
duce them,  fliuter  about  places  in  which 
wool  or  woolen  goods  are  kept,  from  the 
months  of  April  to  the  months  of  October; 
that  is,  almost  from  spring  to  winter,  with 
some  variation,  according  as  the  season  is 
more  or  less  warm.  During  all  that  time 
they  deposit  upon  the  wool  little  eggs, 
which  can  scarcely  be  perceived  ;  from 
these  eggs  are  prodviced  the  caterpillars  ; 
they  are  hatched  in  October,  November, 
and  December ;  they  grow  slowly  at  first, 
and  become  stiff  when  the  weather  is  cold. 
In  March  and  April  they  grow  more ;  at 
that  period  they  cut  off  many  filaments, 
with  which  to  nourish  and  cover  them- 
selves. They  afterwards  form  a  sort  of 
sheath  in  which  they  gradually  envelope 
themselves;  when  they  are  entirely  sheath- 
ed, they  are  in  the  chrysalis  state.  At 
the'  end  of  three  weeks,  they  change  to 
butterflies. 

There  are  three  ways  of  discovering 
when  wool  is  attacked  by  these  insects  : 
at  first,  butterflies  of  a  bright  yellowish 
colour,  and  three  lines  in  length,  are  seen 
flitting  about  it :  afterwards,  are  found 
upon  the  wool,  little  dry,  angular  grains, 
which  appear  grey  if  the  wool  is  white, 
and  blackish  if  it  is  black  :  lastly,  along 
the  walls  and  ceiling  are  perceived  sheaths 
of  a  line  in  diameter,  and  four  or  five  in 
length,  a  little  swelled  in  the  middle,  and 
widened  at  the  extremities. 

It  is  difficult  to  guard  effectually  against 
these  insects.  The  furriers  beat  with  rods 
several  times  during  the  summer,  the  fur, 
VOL.  II. 


and  wool,  which  they  have  in  their  stores  \ 
the  woolen  drapers  are  careful  to  brush 
their  cloths  frequently;  but  these  pre- 
ventives would  be  ineffectual,  it  it  were 
requisite  to  keep  large  quantities  of  wool. 
I  know  of  no  other  than  to  place  it  as  1 
have  directed,  taking  care  to  kill  all  the 
butterflies  which  are  found  upon  the  walls, 
and  to  search  for,  and  sweep  down  the 
sheaths.  The  penetrating  substances 
which  have  been  proposed  are  of  no 
use. 

Of  Washing  the  Wool. 

The  wool,  before  it  can  be  used,  must 
be  freed  from  a  great  proportion  of  that 
oily  matter  (in  French  called  suint)  with 
which  it  is  impregnated,  and  be  cleansed 
from  all  the  filth  which  adheres  to  it.  As 
the  wool  of  merinos  contains  more  grease 
than  that  of  common  breeds,  and  as  it  is 
shorter  and  more  curled,  it  is  usually 
dirtier,  so  much  so,  that  a  flock  of  meri- 
nos may  be  distinguished  at  a  distance  by 
this  mark  alone.  Common  wool  is  more 
easily  cleared  of  its  grease  than  the  fine 
kinds;  nothing  more  is  requisite  than  to 
wash  it  in  water  which  is  a  little 
warmed,  or  by  being  exposed  to  the  heat, 
of  the  atmosphere.  If  the  sheep-houses 
are  kept  clean  by  frequently  changing 
the  litter,  if  the  sheep  are  not  Led  through 
dust,  and  if  their  folds  are  not  upon  a  dus- 
ty soil,  the  fleeces  are  more  profitable  to 
the  merchant  or  manufacturer  who  pur« 
chases  them,  because  they  lose  less  in 
washing.  It  is  desirable  that  the  propri- 
etors of  merinos  attend  habitually  to  the 
cleanliness  of  the  fleeces,  and  particularly 
at  the  time  of  shearing,  by  preventing  any 
dung  from  getting  among  the  wool,  of 
which  manufacturers  sometimes  justly 
complain.  A.».d  this  should  be  attended 
to,  not  only  from  considerations  of  probi- 
ty, but  also  that  the  manufacturers  may 
have  no  pretext  for  beating  down  the 
price  of  the  wool.  But  notwithstanding 
all  the  care  of  the  proprietors,  the  fleeces 
become  more  or  less  dirty,  and  conse- 
quently lose  more  or  less  in  weight,  ac- 
cording to  the  nature  of  the  soil  on  which 
the  sheep  are  kept ;  so  that  it  is  best  to 
wash  the  wool  and  put  it  nearly  in  the 
condition  in  which  it  is  when  sold  by  the 
Spaniards,  or  at  least  to  clear  it  of  the 
greatest  part  of  its  filth. 

Many  people  endeavour  to  imitate  the 
Spaniards;  and,  as  is  always  the  case, 
when  a  first  attempt  is  made  at  a  process 
which  is  not  understood,  the  wool  was 
but  imperfectly  washed,  and  cleared  of 
its  grease.  The  manufacturers  complain- 
ed of  it ;  they  said  it  was  ill  washed,  knot- 
ty and  brown  ;  they  preferred  buying  K 


woo 


VtOQ 


in  the  stste  in  which  it  was  when  taken 
from  the  animal.  In  which  they  were 
right  :  For  Mr.  Hoard  has  remarked  that 
when  wool  is  imperfectly  washed,  it  can- 
not be  properly  cleaned  by  a  second  ope- 
ration Latterly,  people  have  in  many 
places  been  more  successful,  notwith- 
standing what  the  manufacturers  say, 
who,  for  the  most  part,  being  guided  by 
interest,  pretend  to  see  no  difference  be- 
tween what  is  well,  or  what  is  ill  done. 
Il  must,  however,  be  confessed  that  many 
people  in  France  do  not  yet  wash  it  well. 
If  v\e  can  establish  laundries,  we  shall  be 
able  to  offer  for  sale  wool  like  that  which 
comes  from  Spain  All  haggling-  between 
the  owners  of  flocks,  and  manufacturers, 
will  be  pre\ tnied  ;  the  wool  will  be  sold 
according  to  iis  quality.  The  expense  of 
carriage,  as  has  been  already  observed, 
will  be  saved,  and  no  pretext  will  be  left 
for  purchasing  at  a  low  price.  This  is 
still  wanting  10  complete  our  improve- 
ments, and  to  enable  us  to  arrive  at  the 
end  proposed  in  introducing  merinos  in- 
to France. 

Above  twenty  years  ago,  I  procured  in- 
formation in  Spain  upon  this  subject.  I 
am  a  so  indebttd  for  information  to  Mr. 
Pe \  .fi  re  tie  Cere,  w  ho  has  given  me  the  plan 
of  a  laundry,  drawn  by  himself  upon  the 
spot. 

In  Fiance,  wool  cannot  be  well  wash- 
ed, except  between  the  time  of  shearing 
and  the  end  of  October,  because  time  is 
necessary  to  dry  it. 

The  fia.-  i  operation  is,  to  part  the  differ- 
ent qualities,  that  they  may  be  washed 
separately.  Practice  teaches  to  distin- 
guish the  various  sorts.  After  this,  the 
Wool  is  spread  upon  hurdles,  tossed  about 
and  beaten  with  rods,  in  order  to  clear  it 
as  much  as  possible  from  dust  and  other 
dirt  ;  all  the  dung,  pitch,  &c  must  be 
picked  out  by  hand  ;  it  is  then  combed 
with  a  little  instrument  that  has  short 
curved  teeth,  set  far  apart.  This  ope- 
ration must  precede  every  mode  of  wash- 
ing. 

I  shall  first  give  Gilbert's  mode  of 
washing  wool,  with  the  more  confidence, 
as  I  found  that  it  was  followed  in  a  fa- 
mous manufactory  at  Louviers.  The 
workmen  may  perhaps  have  concealed  a 
part  of  thr  ir  process  from  me ;  yet  it  is 
certain  that  the  method  I  am  about  to  ex- 
plain, answers  very  well.  I  shall  after- 
wards describe  the  method  of  washing  on 
a  great  scale,  brought  by  Mr.  Poyfere  He 
Cere  from  Spain,  with  the  description 
and  plan  of  the  fine  laundry  at  Alfaro. 

Gilbert's  Method. 
"  The  fleeces  are  put  into  tubs  or  casks, 


or  any  other  vessels  of  a  capacity  suited 
to  the  quantity  of  wool  to  be  washed. — 
When  thej  are  filled  with  wool  gently 
pressed  down,  but  not  trampled,  water 
warmed  to  30  or  40  degrees  (of  Reaumur, 
equal  to  67  1-2,  or  90*of  Farenheit)  is  to 
be  poured  in  gradually,  till  it  covers  the 
wool  The  next  morning,  or  at  the  end 
of  twenty-four  houis,  the  washing  is  to 
be  begun  ;  the  soakmg  should  not  con- 
tinue less  than  18  hours.  In  order  to 
avoid  trouble,  the  tubs  should  be  placed 
as  near  as  possible  to  the  place  where 
the  washing  is  performed.  The  water  in 
which  the  wool  is  soaked  becomes  filled 
with  grease ;  it  is  this  water  which  is 
most  necessary  in  the  washing;  and  care 
should  be  taken  not  to  waste  it ;  some  of 
it  is  to  be  poured  into  caldrons,  and  heat- 
ed to  50  or  60  (112  1-2  or  135)  degrees  ; 
a  heat  below  50  (112  1-2)  degrees  would 
not  be  sufficient ;  if  above  60  (135)  it 
would  crisp  the  wool,  and  render  it  hard 
and  brittle.  The  proper  temperature  may 
be  determined  without  the  aid  of  a  ther- 
mometer ;  it  should  be  just  that  at  which 
the  hands  cannot  be  held  in  the  water 
without  scalding  them. 

"  When  the  water  is  at  this  tempera- 
ture, some  wool  is  put  into  the  cauldron  : 
the  less  that  is  put  in  at  a  time,  the  more 
completely  is  the  end  answered  A  smooth 
stick,  or  rather  a  smooth  wooden  fork, 
should  be  employed  to  stir  the  wool, 
which  should  be  continually  lifted  up,  in 
order  to  open  it,  and  render  it  more  per- 
meable ;  if  it  were  turned  over,  it  would 
twist,  and  thus  impede  the  subsequent 
operations.  After  having  been  immersed 
three  or  four  minutes,  it  is  to  be  taken 
out,  either  with  the  hands  or  with  the 
fork  ;  it  is  put  into  a  basket,  which  is  held 
a  short  time  over  the  cauldron,  to  drain 
and  to  save  the  greasy  water.  As  the 
water  in  the  caldron  diminishes,  it  must 
be  replenished.  If  it  become  muddy,  the 
caldron  must  be  entirely  emptied,  and 
fresh  water  from  the  tubs  poured  in.  The 
water  is  warm  enough  if  the  wool  wash- 
es well;  before  taking  it  out  of  the  cal- 
dron, it  should  be  tried  from  time  to  time. 
It  would  be  well  if  the  place  where  this 
operation  is  performed  was  under  cover  -. 
this  cannot  always  be  the  case,  for  which 
reason  fine  weather  should  be  chosen. 
When  the  wool  is  taken  out  of  the  cal- 
drons, it  is  to  be  carried  near  the  place 
where  it  is  to  be  washed ;  baskets  are 
made  use  of,  for  this  purpose.  It  is  not  a 
matter  of  indifference  what  kind  of  water 
is  used ;  the  best  is  that  which  washes 
linen  well,  in  which  vegetables  are  soon 
cooked,  which  makes  good  soap-suds, 
and  which  is  very  good  to  drink ;  running 


woo 


woo 


water  is  better  than  stagnant  water;  well 
water  is  the  worst;  if  no  other  can  be 
procured,  it  should  be  previously  drawn 
and  exposed  to  the  air  several  days,  or  it 
should  be  boiled. 

"  To  wash  wool  effectually  in  running- 
water,  two  open  wrought  baskets  should 
be  placed  in  the  stream,  one  higher  up 
than  the  other,  care  being  taken  thai  the 
water  does  not  rise  to  the  top  of  the  bas- 
kets, lest  the  wool  be  carried  away.  The 
washing  is  done  in  the  lower  basket,  and 
the  wool,  when  washed,  is  thrown  into  the 
one  which  is  higher  up  ;  it  there  takes  its 
last  degree  of  purity  Care  should  be  ta- 
ken not  to  rub  the  wool ;  it  is  sufficient  to 
move  it  about,  rapidly  in  the  water,  and  to 
open  it  as  much  as  possible  with  the  rake; 
it  should  be  drawn  continually  from  one 
part  of  the  basket  to  another*  As  soon 
as  the  wool  opens  freely  and  floats  on  the 
surface  like  a  cloud,  and  the  water  of  the 
first  basket  becomes  clear,  it  is  taken  out 
to  dry. 

"  When  the  washing  is  performed  in 
water  that  does  not  flow,  baskets  with 
two  handles  at  the  sides,  are  made  use  of, 
and  are  plunged  repeatedly  into  the  wa- 
ter, until  it  ceases  to  be  fouled  by  the 
wool." 

Gilbert,  directs  a  press  to  be  used,  in 
order  to  squeeze  the  water  out  of  the 
wool,  or  a  compression  produced  by  two 
strong  men  twisting  a  cloth  into  which 
the  wool  is  put.  This  method,  which 
does  no  injury  to  the  wool,  accelerates 
the  drying  of  it,  and  is  convenient  when 
the  season  is  far  advanced  A  single  fine 
day  is  afterwards  sufficient. 

A  spot  of  short  thick  grass  should  be 
chosen,  on  which  to  dry  the  wool,  unless 
there  be  a  building  constructed  for  the 
purpose.  The  place  must  be  first  clean- 
ed and  swept,  so  that  no  filth  may  adhere 
to  the  wool.  It  would  be  better  to  dry 
it  upon  hurdles  or  upon  flint-stones. 

According  to  Gilbert,  merino  wool  well 
washed,  and  well  dried,  loses  two-fifths 
of  the  weight  which  it  had  before  wash- 
ing ;  and  according  to  our  own  observa- 
tions, it  loses  three-fifths,  or  even  fifty  per 
cent. 

In  all  the  manufactories,  a  last  washing 
is  given  to  wool  brought  from  Spain, 
which  never  comes  thoroughly  washed  ; 
it  loses  in  this  last  operation  from  fifteen 
to  twenty  per  cent.  To  the  water  in  which 
the  wool  is  soaked,  urine  and  potash  are 
added.  According  to  Gilbert,  these  ad- 
ditions are  useless.  If  the  wool  be  soak- 
ed in  warm  water  for  eighteen  or  twenty- 
four  hours,  it  preserves  its  flexibility  and 
elasticity  ;  and  it  is  whiter  than  that  which 
comes  from  Spain. 


Method  recommended  by  Mr.  Girou  de 
lluz<iringue$ 

A  proprietor  in  the  department  of  Avey- 
ron,  who  has  succeeded  well  in  cleaning 
his  merino  wool,  say  s  that  he  soaked  it 
twenty-four  hours  in  cold  water,  to  obtain 
the  grease.  1  think  that  warm  water 
would  be  preferable.  Mr.  Girou  de  Bu- 
zaringues  advises,  properly  I  think,  to 
spread  the  fleeces,  and  to  place  them  in 
tubs,  with  the  outside  of  the  fleeces  up- 
permost, lest  the  pressure  of  the  water, 
if  they  were  placed  otherwise,  should  ren- 
der them  impermeable.  When,  for  the 
purpose  of  obtaining  greasy  water,  he 
employs  coarse  wool,  which  is  always  dir- 
tier, he  strains  the  water.  On  these  three 
points  he  differs  from  Gilbert,  whose  me- 
thod, on  the  whole,  he  follows. 

The  methods  recommended  by  Gilbert 
and  Mr.  Girou,  may  be  practised  by  any 
body.  Every  one  may  wash  his  own  wool, 
if  he  follow  the  directions  given.  It  is 
only  necessary  to  proportion  the  appara- 
tus and  water  to  the  quantity  of  the  wool 
to  be  washed. 

Spanish  Method. 
In  Spain,  where  numerous  flocks  belong 
to  great  proprietors,  buildings  have  been 
erected  for  the  purpose  of  washing  wool) 
in  which  are  at  once  united,  economy  of 
time  and  expense,  and  where  the  wool  is 
cleansed  sufficiently  for  the  subsequent 
operations  which  it  is  to  undergo  in  the 
manufactories.  This  was  a  subject  wor- 
thy of  inquiry.  Mr.  de  Poyjere  de  Cere  has 
afforded  us  every  requisite  information, 
by  giving  us  an  exact  description  of  one 
of  their  fine  laundries,  of  which  he  took  a 
drawing  upon  the  spot.  It  is  that  of  \1- 
faro,  where  the  wool  of  the  Pauiar,  Mou- 
tarco,  Turbietta,  and  other  famous  flocks, 
is  carried  every  year  to  be  prepared,  at  a 
small  expense,  and  afterwards  sold  to  fo- 
reigners. 

The  united  waters  of  the  Eresma,  and 
other  streams,  which  have  their  source 
in  the  mountains  which  separate  Old  from 
New  Castille,  flow  towards  Segovia,  and 
thence  into  reservoirs  or  basins,  at  Alfaro. 

"  These  reservoirs,  says  Mr.  de  Poyferet 
contain  above  one  hundred  and  fifty -eight 
thousand,  nine  hundred  and  four  cubic 
feet  of  water  ;  an  immense  resource,  sup- 
plied by  a  constant  stream,  which  serves 
to  afford  a  temporary  supply  to  the  laun- 
dry, if  at  any  time  the  stream  becomes 
muddy  and  unfit  for  use. 

"  The  water  being  admitted  into  the 
laundry,  and  the  wool  having  been  picked 
by  hand,  and  separated  into  first,  second, 
third  qualities,  and  refuse,  it  is  placed  un- 
der a  shed  near  to  the  vats. 


woo 


woo 


"The  vats  are  filled  to  two-thirds  of 
their  depth  with  hot  water,  by  means  of  a 
cock  communicating-  with  a  boiler.  This 
water  may  be  tempered  at  pleasure  with 
cold  water.  A  man  is  stationed  to  regu- 
late it,  which  he  does  by  putting  his  leg- 
into  each  vat,  and  ordering  hot  or  cold 
water  to  be  added,  as  he  sees  proper,  un- 
til the  degree  of  heat  is  such  that  he  can 
no  longer  endure  it  without  being  scalded. 
He  then  gives  the  signal  for  immersing  the 
wool ;  the  length  of  the  immersion  is  re- 
gulated by  the  time  requisite  for  emptying 
the  second  and  third  vats  before  return- 
ing to  the  first. 

"  A  man  descends  into  one  of  the  vats, 
takes  out  a  certain  quantity  of  wool,  and 
puts  it  into  wicker  baskets. 

"  Children,  holding  fast  by  lines,  get 
upon  the  wool  in  the  baskets,  and  tread 
it  with  their  feet,  to  press  out  the  greasy 
water  with  which  it  is  charged.  This  wa- 
ter escapes  through  the  drains  of  the  gra- 
ted-.vork,  on  which  the  baskets  are  pla- 
ced, into  a  cistern,  and  empties  itself  out 
of  the  laundry. 

"The  wool  thus  pressed,  is  emptied 
out  upon  a  grated-work.  Three  children 
take  it  up,  divide  it,  and  deposit  it  on  the 
margin  of  one  of  the  layers.  A  man  (this 
is  the  principal  hand)  placed  upon  a  flight 
of  steps,  takes  the  wool  handful  by  hand- 
ful, divides  it  again,  and  lets  it  fail  into  a 
canal. 

"  Two  men  are  placed  in  a  laver,  rest- 
ing their  hands  on  a  cross-piece,  which  is 
firmly  fixed,  who  move  their  right  and 
left  leg  alternatively,  so  as  to  drive  back 
the  water  and  separate  the  flocks  of 
wool.  The  depth  of  the  water  in  the  la- 
ver is  from  11  to  12  inches. 

"  Four  men  placed  in  the  canal  of  the 
later,  resting  their  hands  upon  the  sides 
of  it,  repeat  the  motions  of  the  two  men 
stationed  in  the  basin. 

Four  other  men,  also  standing  in  the 
canal,  gather  up  the  wool  as  it  is  carried 
along  by  the  current  of  water.  They  make 
it  up  into  bundles,  without  wringing  or 
twisting  it,  press  out  the  water,  and 
throw  the  wool  upon  the  floor  A  child 
takes  it  and  deposits  it  on  a  shelving 
drainer.  After  passing  through  several 
hands,  it  is  finally  placed  in  a  heap  on  the 
top  of  the  drainer. 

The  wool  is  suffered  to  remain  here 
during  tour  and  twenty  hours.  At  the 
expiration  of  which  time,  it  is  carried  to  a 
neighbouring  meadow,  which  has  been 
raked  and  even  swept  with  care,  and 
there  spread  out  in  small  parcels  until  it 
is  quite  dry,  which  commonly  requires 
three  or  four  days. 


The  wool  which  escapes  the  four  men, 
placed  in  the  canal,  is  carried  by  the 
stream  into  a  wooden  cage,  whose  bot- 
tom and  sides  are  covered  with  a  net  that 
has  very  small  meshes.  Three  men  sta- 
tioned in  this  cage,  stir  about  the  wool 
with  their  feet ;  and  as  they  gather  it  up, 
they  make  itinto  small  bundles  which  they 
press  out  with  their  hands,  and  which 
they  throw  upon  the  floor,  where  two 
children  receive  it  in  small  baskets, 
squeeze  it,  and  carry  it  to  the  great  heap 
at  the  top  of  the  drainer. 

Such  is  the  operation  of  washing,  prac- 
tised in  Spain,  for  wool  of  the  highest  re- 
putation. At  Alfaro,  the  work  begins  at 
three  o'clock  in  the  morning,  and  does 
not  end  till  night.  In  one  working  day, 
which  is  about  sixteen  hours,  three  hun- 
dred French  quintals  (antient  measure) 
of  wool  are  washed. 

Method  communicated  by  a  Manufacturer 
of  Montjoie. 
A  manufacturer  of  Montjoe,  in  the  de- 
partment of  lioer,  is  of  opinion,  that  pro- 
prietors of  merino  flocks,  who  are  distant 
from  manufactories,  might  advantageous- 
ly confine  themselves  to  a  simple  wash- 
ing, so  as  to  take  off  nearly  all  the  filth, 
and  to  preserve  grease  sufficient  for  the 
washing  at  the  manufactory.  He  directs 
the  different  sorts  of  wool,  of  which  a 
fleece  is  composed,  to  be  picked,  and  put 
separately  into  a  basket ;  the  wool  to  be 
placed  in  a  stream  of  water,  and  taken 
out  and  plunged  in  again  from  time  to 
time ;  to  be  stirred  with  a  wooden  rake ; 
and  when  no  more  filth  comes  out,  to  be 
dried  in  the  open  air.  According  to  him, 
fleeces  thus  cleaned  do  not  lose  in  the 
washing  at  the  manufactory  more  than 
thirty-three  per  cent,  while  that  which  is 
sold  dirty,  and  with  all  its  grease,  may 
lose  as  much  as  seventy-five,  if  the  ani- 
mals have  been  ill  taken  care  of,  and  kept 
in  dusty  places.  This  at  least  is  certain, 
that  having  tried  this  method  with  a  small 
quantity  of  my  wool,  a  distinguished  ma- 
nufacturer of  Verviers,  who  saw  it,  assu- 
red me  that  it  would  wash  perfectly  well 
at  the  manufactory,  and  that  this  was  the 
state  in  which  it  answered  best.  If  this 
assertion  be  true,  as  in  all  probability  it 
is,  nothing  is  easier  than  to  give  the  wool 
a  first  preparation,  which  will  diminish 
the  expense  of  carriage,  which  may  be 
effected  by  all  proprietors  of  flocks  in  the 
neighbourhood  of  streams  of  water,  and 
which  will  not  prevent  the  last  washing, 
indispensable  before  the  wool  is  manufac- 
tured. If  this  method  be  pursued,  the 
coarse  and  very  dirty  parts  of  the  fleeces 


woo 


woo 


should  be  excluded,  such  as  the  wool  of 
the  forehead,  of  the  belly,  the  thighs  and 
the  legs.  This  mode  of  washing  answers 
nearly  to  washing-  the  wool  upon  the 
sheep'*  back,  except  that  it  cleanses  it 
more  effectually.  If  the  •  manufacturers 
will  be  just  enough  to  give  a  price  for 
this  wool,  such  as  to  compensate  for  its 
diminution  in  weight,  and  proportioned  to 
what  they  would  have  given  if  they  had 
bought  it  dirty  and  greasy,  I  do  not  doubt 
that  many  proprietors  "will  adopt  this 
method. 

Washing  at  the  Manufactory. 
The  trashing  at  the  manufactory  is  per- 
formed in  the  following  manner.  A  cal- 
dron, capable  of  holding  with  ease  from 
30  to  40  kilogrammes  of  wool,  is  filled 
with  a  mixture  of  two-thirds  water,  and 
one-third  urine,  and  is  heated.  When  this 
liquid  arrives  at  the  temperature  of  from 
40  to  45  degrees,  (90  to  101  of  Farenheit) 
BO  that  the  hand  can  bear  it,  the  wool  is 
put  in,  and  left  there  half  an  hour,  being 
stirred  about  continually  with  much  care, 
by  means  of  small  wooden  forks  ;  it  is  then 
taken  out  and  drained,  then  washed,  in 
small  parcels,  in  a  river  or  brook,  until  it 
ceases  to  foul  the  water,  and  finally  dried 
lor  use.  In  some  manufactories,  the  mix- 
tures made  with  three  quarters  water,  and 
one  quarter  urine,  which  answers  as  well. 

Private  individuals  who  wish  to  wash 
small  quantities  of  wool,  in  order  to  manu- 
facture it  at  home,  may  employ  Gilbert's 
method,  or  that  recommended  by  the  ma- 
nufacturer of  Montjoie ;  whichever  be 
adopted,  it  must  be  succeeded  by  the 
wash  with  urine  just  mentioned.  If  no 
river  nor  rivulet  be  near  at  hand,  baskets 
filled  with  wool  may  be  plunged  into  tubs 
of  clean  water,  which  must  be  constantly 
renewed.  This  operation  is  indeed  long  ; 
and  I  do  not  recommend  it  unless  the 
quantity  of  wool  is  small. 

Sale  of  Wool. 
Two  opposite  interests  meet  in  the  sale 
of  wool,  that  of  the  proprietor  of  the 
flock,  and  that  of  the  manufacturer.  If 
they  deal  by  an  intermediate  agent,  that 
is,  by  means  of  a  merchant  or  a  broker, 
a  third  interest  arises,  distinct  from  both. 
It  is  best  for  the  manufacturer  to  pur- 
chase immediately  from  the  proprietor 
they  thus  save  between  them  the  profit 
which  would  have  gone  to  the  third  per- 
son ;  but  it  is  difficult  to  effect  this. 
Those  who  raise  flocks  are  not  acquaint- 
ed with  the  manufacturers,  and  have  no 
way  of  applying  to  them  ;  they  are  there- 
fore obliged  to  wait  until  traders  come  to 
them  ;  and  thus  they  deal  with  none  but 
merchants,  who  afterwards  dispose  of 
the  wool  to  the  manufacturers. 


The  manufacturers,  however  send  their 
agents  into  t  he  country  to  purchase  wool 
at  a  low  price,  by  persuading  the  country 
people  that  what  they  offer  is  the  current 
price,  and  that  it  is  for  their  advantage  to 
accept  thai' offers.  The  want  of  money, 
and  the  fear  of  losing  by  delay,  induce 
them  to  sell  at  a  low  price.  Some  great 
proprietors  of  flocks,  obtain  better  infor- 
mation ;  they  learn  the  prices  of  wool  in 
Spain,  know  the  vents  for  manufactures, 
and,  being  less  in  haste,  bring  the  manu- 
facturers nearly  to  the  just  price. 

It  is  customary  to  give  four  pounds  of 
wool  over  and  above  every  hundred  ;  the 
manufacturers  call  this  a  gift.  This  cus- 
tom is  to  the  disadvantage  of  the  vender  ; 
it  would  be  better  to  make  the  bargains 
for  a  real  and  precise  quantity,  without 
any  addition.  This  custom  has  arisen  from 
the  allowance  which  was  formerly  made 
for  the  weight  of  the  bands.  The  manufac- 
turers have  since  insisted  upon  the  gift  of 
four  per  cent,  and  an  allowance  for  the 
bands  besides.  The  proprietors  of  flocks 
should  consent  to  neither  of  these  reduc- 
tions ;  the  weight  of  the  bands  is  nothing, 
if  pack-thread  or  rushes  be  employed. 

The  vender  derives  an  advantage  from 
disposing  of  his  wool  immediately  after 
shearing ;  because,  in  drying,  the  weiglit 
is  diminished.  It  is  also  profitable  to  the 
purchaser,  to  obtain  it  as  soon  as  possible 
after  it  is  shorn,  because  it  can  be  cleaned 
better,  as  it  contains  more  gn-ease ;  the 
season  is  besides  more  favourable  for 
washing.  If  it  be  sold  ready  washed,  the 
above  advantages  do  not  result  from  sell- 
ing it  at  one  time  rather  than  at  another. 

Many  French  manufactories  had  con- 
tracts, for  a  certain  number  of  years,  with 
proprietors  of  flocks  in  Spain,  for  the  pur- 
chase of  their  wool.  It  was  usual  for  the 
latter  to  give  credit.  Nothing  hinders 
similar  borgains  from  being  made  in  our 
own  country.  Flocks  remarkable  for  the 
fineness  of  their  wool,  would  undoubted- 
ly find  manufacturers  desirous  of  securing 
it  for  themselves. 

By  experiments  made  with  great  care 
and  exactness  in  1807,  which  I  myself 
witnessed,  it  is  proved  that  the  wool  of 
French  merinos  is  equally  as  strong  and 
elastic  as  that  of  Spanish  merinos.  By 
an  attentive  comparison,  it  has  been  dis- 
covered that,  when  employed  in  manufac- 
tures, their  products  are  strictly  equal  in 
quality  and  quantity  ;  consequently,  the 
price  of  French  merino  wool  ought  to  be 
regulated  by  that  of  the  Spanish  merinos. 

Mr.  John  Luccock,  a  celebrated  En- 
!  glish  wool  stapler,  of  Leeds,  (Yorkshire) 
writes  as  follows  on  the  essential  qualities 
of  wool : 


woo 


woo 


"  If  the  improvement  of  wool  consist 
entirely  in  rendering  it  better  adapted  to 
manufactures,  the  growers  very  natural- 
ly ask,  what  are  those  properties  which 
the  workmen  deem  most  valuable  ?  what 
should  be  our  definite  and  particular  ob- 
ject when  we  attempt  to  cultivate  the 
fleece  ?  not  possessing  information  upon 
the  subject,  we  are  liable  they  say,  to 
great  mistakes,  and  our  wool  may  derive 
its  worst  qualities  from  the  very  mea- 
sures which  we  thought  best  adapted  to 
promote  improvement.  Too  often  our 
knowledge  upon  subjects  of  this  nature, 
has  been  collected  only  from  obscure 
hints,  casually  dropped  by  the  buyers ; 
some  of  whom  we  have  suspected  of  be- 
ing interested  in  deceiving  us,  and  in  a 
few  instances  have  illiberally  charged 
them  with  combining  to  defraud.  In  ge- 
neral these  gentlemen,  who  we  are  sure 
must  .possess  the  most  accurate  know- 
ledge both  of  wool  and  the  manufacture, 
communicate  information  very  sparingly, 
and  seem  afraid  lest  we,  who  alone  pos- 
sess the  power  of  changing  the  qualities 
of  the  pile,  should  understand  too  much 
of  its  properties  and  its  application .  They 
often  tell  us  that  its  value  has  decreas- 
ed, because  the  demand  for  it  has  lessen- 
ed; and  yet  we  find  no  surplus  of  wool. 
We  are  assured  that  the  articles  into 
Which  our  wool  was  wrought,  have  ceas- 
ed to  be  made,  and  yet  they  appear  desi- 
rous to  purchase  it ;  and  when  we  have 
cultivated  the  qualities,  which  they  once 
extolled,  we  almost  invariably  hear  them 
reprobated  as  the  most  pernicious  altera- 
tions. This  inconsistency  is  too  obvious 
to  escape  our  notice,  and  the  wool  buyer 
must  pardon  us  if  we  trace  it  to  his  ca- 
price, or  a  design  to  mislead  us. 

Such  are  the  complaints  which  the  gra- 
7jer  utters  almost  every  returning  sum- 
mer, such  the  charges  which  he  seriously 
urges  against  the  stapler.  Many  of  them 
are  totally  void  of  foundation,  and  origin- 
ate only  in  the  want  of  better  information, 
or  in  that  suspicion  in  one  party,  which  is 
always  the  offspring  of  ambiguous  con- 
duct in  the  other.  Yet  wherefore  should 
ambiguity  and  suspicion  subsist'  Is  it  be- 
cause the  occupations  of  the  wool  grow- 
er and  the  stapler  are  incompatible  with 
manly  behaviour  and  generous  principles  I 
Or  because  long  established  prejudice  has 
induced  a  habit  of  transacting  business 
equally  dishonourable  to  both  parties  ? 
The  author  of  these  pages  will  deem  him- 
self happy,  if  by  attempting  to  convey  to 
the  wool-grower  some  general  informa- 
tion respecting  the  qualities  of  wool,  he 
shall  be  able  to  quiet  some  of  those  bick- 
erings which  have  long  disgraced  the 


[  transactions  of  the  buyers  and  the  sellers 

'  of  an  article  constantly  used.  In  descri- 
bing them,  he  will  prefer  perspicuity  to 
the  ornaments  of  stile,  and  observe  that 
order  alone  in  which  they  occur  to  recol- 
lection. 

That  wool  is  evidently  most  distinguish- 
ed for  good  qualities,  which  may  be  fa- 
bricated into  a  valuable  article,  by  means 
of  the  implements  in  common  use,  in  the 
most  perfect  manner,  and  with  the  small- 
est degree  of  labour  and  expense.  It 
would  be  idle  to  enquire  what  would  be- 
come the  valuable  qualities  of  the  pile,  if 
a  change  occurred  in  the  taste  of  those 
who  ultimately  consume  woolen  goods,  if 
those  now  in  demand  were  to  be  no  long- 
er made,  or  if  the  implements  of  the  ma- 
nufacture were  more  perfectly  construct- 
ed. The  present  state  of  the  manufac- 
ture, of  the  implements,  and  the  demand, 
must  limit  our  enquiries. 

When  the  fleeces  are  separated  from 
the  back  of  the  sheep,  they  are  invariably 
found  to  contain  a  variety  of  difierent 
kinds  of  wool,  very  frequently  suitable  to 
the  fabrication  of  articles  very  dissimilar 
in  their  nature,  and  adapted  to  processes 
in  the  manufacture  of  a  description  total- 
ly different  from  each  other.  The  chief 
business  of  the  stapler  is  to  separate  the 
portions  of  this  mingled  mass,  to  distri- 
bute them  in  their  proper  order,  and  to 
supply  the  manufacturers  with  the  peculi- 
ar kind  of  wool,  required  by  the  goods 
which  each  of  them  makes.  This  em- 
ployment is  very  different  from  that  which 
occupied  the  stapler's  attention  in  the 
thirteenth  and  the  two  following  centuries, 
when  he  was  engaged  only  in  exporting 
to  a  foreign  market  the  fleeces  of  his 
country,  almost,  if  not  entirely,  without 
assortment.  At  present,  his  occupation 
constitutes  him  the  agent  of  the  manufac- 
turer, or  rather  in  his  hands,  wool  passes 
through  the  first  stage  of  the  process 
adopted  to  render  it  useful ;  and  it  be- 
comes his  business  and  his  interest  to 
watch  the  state  of  trade,  to  notice  the 
changes  in  the  demand  for  different  arti- 
cles, to  remark  the  nature  and  qualities  of 
the  wool,  and  to  point  out  to  the  grower 
the  properties  of  the  fleece,  which  are  suc- 
cessively, of  superior  or  of  smaller  impor- 
tance. The  art  of  sorting  wool,  almost 
unknown  a  few  centuries  ago,  has  been 
very  considerably  improved  during  the 
last  hundred  years ;  and  as  the  division 
of  labour,  in  most  other  branches  of  manu- 
facture, contributed  to  their  advancement, 
so  in  the  fabrication  of  woolens  it  has  pro- 
duced very  essential  benefits.  But  some 
who  are  employed  in  sorting  wool,  situa- 
ted far  remote*  from  the  manufacturers, 


woo 


woo 


and  hearing  none  of  their  complaints, 
cither  have  no  precise  object  in  view,  or 
perform  their  work  so  ill  as  to  render  it 
necessary  to  incur  a  second  expense  for 
workmanship,  or  their  sorts  must  pass  in- 
to the  market  debased  below  their  real 
value.    Persons  to  whom  this  remark  ap- 
plies should  always  recollect,  that  in  eve- 
ry intermixture  of  coarse  and  fine  wool, 
it  is  impossible  to  prevent  the  first  from 
forming  the  exterior  of  the  thread  and  the 
surface  of  the  piece,  so  that  in  all  ill- 
performed  sorting,  only  the  worst  portion 
of  the  wool  becomes  visible,  when  pass- 
ing- through  the  manufacturers  hand. — 
This  employment  which  Dr.  Parry,  who 
engaged  a  person  to  break  some  wool 
after  the  Spanish  manner,  complains  of, 
requires  much  greater  dexterity  than  is 
readily  conceived,  by  those  who  have  on- 
ly seen  it  performed.     Had  a  common 
workman  merely  torn  the  fleece  across  the 
loins,  taken  off  the  skirts,  and  divided  the 
remainder  into  three  parts,  almost  with- 
out indiscrimination,  we  also  should  have 
called  it,  "a  lazy  and  artless  operation  ;" 
and  had  we  been  charged  the  price  for 
the  workmanship,  which  the  doctor  paid, 
we  should  have  expressed  ourselves  in 
terms,  which  we  are  always  sorry  to  utter, 
and  never  wish  to  repeat. 

This  is  the  mode  of  sorting  wool  adopt- 
ed in  Spain  ;  but  the  English  workman, 
finds  it  contribute  to  his  interest,  to  be 
scrupulous  in  the  separation  of  the  pile, 
and  has  introduced  a  much  greater  num- 
ber of  sections,  into  his  method  of  break- 
ing the  fleece.    In  this  country,  there  are 
three  general  kind  of  fleeces,  and  each  of 
them  is  sorted  in  a  maimer  different  from 
the  others.    The  finest  includes  all  those 
adapted  to  the  fabrication  of  woollen  arti- 
cles, and  comprehends  by  far  the  larger 
proportion  of  the  wool  of  the  island  ;  the 
second  comprehends  the  longer  pile,  that 
which  is  suitable  to  worsted  goods  ;  and 
the  other  is  confined  to  wool  of  a  medium 
length,  that  which  is  used  in  the  hose 
trade.    The  number  of  sorts,  into  which 
the  fleeces  of  each  class  are  divided,  is 
always  arbitrary ;  but  custom  has  intro- 
duced an  imperfect  kind  of  system,  to 
which  most  staplers  conform.  The  num- 
ber of  sections  adopted  in  the  hose  trade, 
is  generally  six  or  seven,  and  the  names 
applied  to  them  are  only  two,  Drawing 
and  Matching,  but  distinguished  in  the 
inferior  divisions,  by  the  epithets  com- 
mon, fine,  blue,  brown  and  super.  The 
fleeces  suitable  to  worsted  goods,  when 
considered  upon  a  scale  comprehending 
most  of  that  kind  of  wool,  produced  in 
the  kingdom,  admit  of  about  sixteen  sorts, 
half  of  them  obtained  from  the  wool  of 


sheep,  which  have  been  shorn  more  than 
once,  and  the  others  from  hog  fleeces.-— 
Those  who  break  the  shorter  wools,somc- 
times  make  about  17  different  divisions  in, 
a  pile  of  fleeces,  and  very  few  staplers, 
even  those  who  purchase  the  inferior  par- 
cels of  this  description,  reckon  fewer  than 
nine  sorts  ;  but  manufacturers  sometimes 
content  themselves,  with  three  or  four 
distinctions.  The  names  which  in  the  east 
of  the  kingdom,  are  commonly  applied  to 
the  sorts  broken  out  of  small  fleeces,  fur- 
nish a  curious  illustration  of  the  increas- 
ing fineness  of  the  pile,  since  the  art  of 
sorting  was  first  made  a  distinct  occupa- 
tion, and  likewise  of  the  growing  skill  of 
the  workman,  who  has  almost  constantly 
endeavoured,  to  discriminate  the  size  of 
the  hair  with  greater  exactness.  The 
name  of  the  lowest  sort,  or 

1.  Is  Short -Coarse and  very  descrip- 
tive of  its  character. 

2.  Livery.  ">     Old  sorts  into  which  the 

3.  Abb.  5  fleece  was  formerly  divi- 
ded. 

4.  Second.  Probably  a  second  or  bet- 
ter abb,  and  the  first  alteration  in  the 
mode  of  sorting,  which  arose  either  from 
the  improvement  of  fleeces,  or  in  the  art 
of  breaking  them.  This  and  all  the  sub- 
sequent names,  seem  to  have  been  in 
their  regular  succession,  at  the  top  of  the 
list. 

5.  Bownrights.  Perhaps  intended  to 
convey  the  idea  of  superlative  perfection. 

6.  Head.    Or  chief. 

7.  Super. Head.  An  advance  upon  the 
preceding  sort. 

8.  Picked-Lock.  First  made  perhaps 
in  small  quantities. 

9.  Choice-Lock.    Still  more  excellent. 

10.  Prime-Lock.  The  last  sort  intro- 
duced into  the  list,  and  in  one  instance 
called  Pic-jVic,-  alluding  to  the  celebrat- 
ed society  of  that  name. 

The  names  of  the  others  are  derived 
from  these ;  and  the  sorts  which  they  re- 
present are  introduced,  into  those  parts 
of  the  scale,  where  the  divisions  of  it  were 
sufficiently  wide  to  admit  them.  They 
are  described  as  a  Better  Livery,  Small 
Abb,  Best  Second,  and  by  other  epithets 
of  the  same  kind  This  catalogue  of  sorts, 
rises  according  to  the  hair,  or  fineness  of 
the  pile,  and  is  calculated  to  receive  that 
portion  of  the  fleece,  which  is  adapted  to 
cloths  of  the  lighter  colours  ;  and  in  or- 
der to  receive  what  is  suitable  only  to  the 
stronger  tints,  we  run  parallel  to  it  a  list 
of  sorts,  usually  denominated  Greys,  of 
the  first,  second,  and  third  order.  The 
French  manuf; icturers,  who  are  some- 
times very  ex^ct  in  their  mode  of  sorting, 
"  particularly  for  the  more  delicate  bran- 


woo 


woo 


ches  of  the  manufactures,  have  been  re- 
commended by  M.  Daubenton,  to  make 
use  of  a  micrometer,  in  order  to  ascer- 
tain the  size  of  the  hair,  with  more  per- 
fect nicety. 

The  pile  of  my  own  sorts,  when  exa- 
mined by  means  of  a  lens,  applied  to  a 
graduated  scale,  generally  arranges  itself 
within  the  following  dimensions.  The 
Breech  or  Short  coarse,  receives  all  the 
short  and  very  inferior  locks,  and  the  Li- 
very, those  of  a  finer  kind ;  but  with  i 
considerable  latitude  of  hair.    The  dia 
meter  of  the  pile  in  all  the  others,  will  be 
represented  if  we  divide  an  inch,  which 
we  consider  as  unity,  by  the  number  an 
nexed  to  each  of  the  names. 

Better -Livery,  by  six  hundred. 

Fine-Grey,  by  seven  hundred  and  twen 

Seconds,  by  eight  hundred. 
Downrights,  by  nine  hundred  and  twen 

ty. 

Head,  by  one  thousand. 
Super,  by  eleven  hundred  and  sixty. 
Picked-Lock,  by  twelve  hundred  and 
eighty. 

Choice,  by,  fourteen  hundred. 

A  sample  of  moderately  fine  Spanish 
wool,  reached  sixteen  hundred. 

These  numbers  are  the  average  of  se- 
veral repeated  measurements,  and  are 
considered  by  me,  as  the  standard  of  the 
sorts,  to  whose  names  they  are  affixed. 

It  is  the  object  of  the  woolstapler,  when 
he  purchases  fleeces,  to  obtain  at  a  given 
price,  as  large  a  proportion  as  possible, 
of  the  superior  sorts.  With  him  the.  fine- 
ness of  the  pile  is  the  first  consideration, 
and  the  manufacturers,  his  customers, 
can  always  work  up  wool  of  the  first  qua- 
lity, if  they  could  obtain  it  at  a  price, 
which  would  allow  them  to  meet  the  mar- 
ket. The  thinness  of  the  hair,  can  very 
seldom,  if  ever  be  considered  as  a  detri- 
ment to  the  fleece,  but  coarseness  very 
frequently  unfits  it  for  a  variety  of  pur- 
poses. In  his  search  for  wool  of  a  supe- 
rior quality,  the  stapler  is  perpetually 
urged  by  the  increasing  demand,  for 
goods  of  the  mo^t  delicate  texture  ;  and 
it  should  induce  the  grower  to  collect 
from  his  Hocks,  fleeces  distinguished  by 
their  superior  excellency  The  consump- 
tion of  Spanish  wool  amongst  us,  strongly 
evinces,  that  when  a  taste  for  fine  cloths 
prevails,  the  materials  will  be  obtained  by 
the  manufacturer,  even  though  the  use  of 
them,  tend  to  discourage  our  own  wool- 
growers,  and  to  supersede  the  necessity 
of  our  native  produce.  Nor  is  there  any 
danger  to  be  apprehended,  lest  the  culti- 
vation of  fine  wool,  should  leave  our 
coarser  fabrics  without  the  supply  which 


they  require,  for  the  richer  soils  of  the 
kingdom,  will  continue  to  be  stocked  with 
a  race  of  sheep,  whose  pile  will  not  for 
many  ages,  be  adapted  to  delicate  manu- 
factures ;  and  in  proportion  as  farms  im- 
prove in  the  low  lands  of  Scotland*  and 
almost  through  every  district  in  Ireland, 
we  may  expect  that  the  fleeces  they  yield 
will  be  better  adapted  to  those  purposes, 
for  which  the  middle  wools  of  England 
are  at  present  employed.  But  should  it 
be  necessary  to  import  the  coarser  article, 
it  M  ould  be  much  more  advantageous  to 
purchase  of  foreigners,  what  is  easy  to  be 
procured  from  many  countries,  than  to 
depend  upon  one  haughty  nation,  subju- 
gated to  the  councils  of  our  rivals. 

In  the  present  state  of  the  woollen  ma- 
nufacture, the  length  of  the  staple,  is  an 
object  of  very  considerable  importance. 
It  is  that  which  destines  the  fleece  to  fa- 
brics very  different  in  their  nature,  and 
produced  by  instruments  of  dissimilar 
construction     It  will  be  difficult  to  con- 
vey to  those  who  are  not  acquainted  with 
the  structure  of  the  card,  and  the  comb, 
an  idea  of  the  mode  in  which  they  are  ma- 
naged, and  the  purposes  for  which  they 
are  used,  sufficiently  accurate  to  enable 
them  to  conceive  the  object  of  the  manu- 
facturer, or  the  qualities  of  the  wool  suit- 
ed to  their  respective  operations.  The 
card  is  a  small  oblong  board,  furnished 
with  a  great  number  of  short  crooked 
wires  or  hooked   teeth,  upon  which  the 
wool  to  be  wrought,  is  hung  by  drawing 
it  over  them,  in  a  direction  contrary  to 
that  in  which  the  hooks  are  bended. — 
When  full,  the  instrument  is  placed  upon 
the  thigh  of  the  workman,  with  the  teeth 
upwards,  and  held  there  by  the  left  hand, 
assisted  by  a  handle  attached  to  the  card, 
while  another  card  of  similar  construc- 
tion, having  the  teeth  downwards,  and  in 
a  direction  opposite  to  those  of  the  first, 
is  drawn  over  it  with  the  right  hand.  The 
operation  is  continued  until  the  workman 
thinks  the  wool  completely  torn  between 
the  teeth,  broken  and  blended ;  when  by 
a  pecular  mode  of  taking  it  from  these 
instruments,  he  renders  it  fit  for  the  spin- 
ning wheel.  The  object  here  is  to  break 
the"' wool  completely,  to  blend  it  most  in- 
timately, and  to  form  it  into  a  thin  roll, 
or  "  rovelling,"  of  the  slightest  texture 
imaginable,  held  together  only  by  the  na- 
tural hookedness  of  the  pile,  or  that  dis- 
position which  it  has  to  assume  a  zig  zag, 
or  waved  form.    Hence  it  is  evident  that 
the  two  chief  qualities,  which  carding 
wool  requires,  is  shortness  of  pile,  and  a 
disposition  in  the  haft',  to  assume  a  crum- 
pled or  spring-like  shape.    If  the  first  of 
these  be  ill  adapted,  labour  becomes  ne- 


woo 


woo 


ccssary  to  reduce  the  immoderate  length 
of  (he  staple  ;  a  greater  expense  is  incur- 
red, and  more  time  is  employed  in  work- 
ing- it  ;  considerations  which  always  have 
their  weight  among-  clothiers,  and  ought 
not  to  be  disregarded  by  the  grazier.  It 
appears  scarcely  possible,  that  the  staple 
of  clothing  wool,  at  least  that  part  of  it, 
employed  in  the  manufacture  of  the  finer 
fabrics,  should  be  too  short,  if  it  possess 
only  that  degree  of  crumpledness,  which 
will  enable  it  to  form  a  rovelling.  One 
great  advantage  of  the  modern  machinery 
arises  from  the  more  complete  and  uni- 
form manner,  in  which  the  staple  is  brok- 
en ;  and  the  chief  point  of  attention  in 
the  scribbler  is  to  break  it  no  farther,  than 
the  hookedness  of  the  pile  will  admit 
of. 

The  peculiar  shrivelling  quality  in  wool, 
cannot  prevail  in  too  high  a  degree,  if  it 
be  destined  to  make  any  kind  of  goods, 
which  require  a  close,  and  smooth  sur- 
face ;  for  the  greater  number  of  the  mi- 
nute curves  which  it  contains  in  a  given 
length  of  the  pile,  so  much  the  more  it 
may  be  broken  without  injury,  and  every 
portion  retain  a  sufficient  degree  of  cur- 
vature to  link  itselt  with  its  neighbours, 
forming  an  inconceivably  thin  and  trans- 
parent texture.  The  thinner  this  texture 
can  be  produced,  and  the  greater  degree 
of  surface  that  can  be  given  to  it,  so  much 
the  longer  thread  it  will  yield,  and  the 
cloth  made  from  it,  partake  of  a  propor- 
tionable degree  of  delicacy.  The  neces- 
sity of  this  singular  property  of  clothing 
wool,  is  obvious  from  the  manner  in  which 
hair,  a  straight  and  smooth  pile,  is  dissi- 
pated when  wrought  upon  the  same  en- 
gines ;  the  particles  possessing  no  means 
of  uniting  themselves  together,  drop  sin- 
gly from  the  machine,  produce  no  rovel- 
ling, and  cannot  be  spun  in  the  same  man- 
ner as  a  woollen  thread.  When  the  pile 
is  intended  to  form  some  of  those  fabrics, 
distinguished  by  a  long  and  even  knap, 
such  as  blankets  and  cloths,  intended  for 
large  surtouts,  too  great  a  proportion  of 
this  shrivelling  quality,  might  be  detri- 
mental, by  rendering  the  knap  less  uni- 
form  and  compact.  But  in  the  surfaces, 
which  remain  loose,  and  carefully  disar- 
ranged, if  I  may  be  allowed  the  expres- 
sion, as  in  the  instances  of  cloths  for  light 
great  coats,  frizes  and  swan-downs,  it  is 
highly  useful;  and  this  variety  among 
other  circumstances, plainly  suggests  how 
desirable  it  is,  that  wool  should  be  pro. 
duced  for  a  definite  purpose,  and  not  as 
it  generally  is,  at  random,  and  possessing 
properties,  of  which  the  grower  is  either 
entirely  ignorant,  or  oberving  them  knows 
not  their  value,  nor  their  use, 

VOL.  II, 


Yet  the  cultivator  of  wool,  must  not 
'  suppose  that  every  kind  of  curvature, 
I  which  he  observes  in  the  fleeces  of  his 
!  sheep,  is  a  symptom  of  aptness  inthebro- 
j  ken  pile  to  link  together,  and  form  a  ro- 
velling, the  first  rudiment  of  the  thread  ; 
I  for  there  is  a  sort  of  crumplednes  in  the 
1  staple,  which  the  clothier  avoids,  with 
almost  as  much  care,  as  he  employs  in 
seeking  for  the  other  kind.  It  is  distin- 
guished by  a  singular  adaptation  of  the 
curves,  in  the  pile  to  each  other,  as  though 
they  had  been  formed  by  some  external 
pressure  upon  the  staple,  and  not  by  a 
cause  effecting  every  individual  hair,  se- 
parately as  it  passed  through  the  pores 
of  the  skin.  The  distribution  of  the  hair 
in  staples  of  this  description,  bears  some 
resemblance  to  that  of  the  grain,  in  a  very 
crooked  piece  of  timber,  or  perhaps  it  is 
more  exactly  like  waved  bars  of  metal, 
formed  in  such  a  manner,  that  the  con- 
vex part  of  one,  fits  into  the  concavity  of 
another.  We  can  assign  no  reason,  why 
this  kind  of  wool  should  be  disapproved, 
unless  it  arise  from  the  superior  length  of 
the  curves,  by  which  means  the  staple 
cannot  be  broken,  so  much  as  it  ought 
to  be,  and  every  portion  still  retain  its 
power  of  uniting,  with  those  which  are 
near  to  it;  this  peculiarity  however,  is 
known  to  be  detrimental,  and  ought  to  be 
avoided. 

In  some  of  the  finer  kinds  of  wool  pos- 
sessing this  shrivelling  property,  in  a 
high  degree,  the  chord  subtending  the 
arc,  is  sometimes  not  longer  than  the 
hundredth  part  of  an  inch  ;  but  in  those 
of  inferior  quality,  where  the  curvature 
is  not  of  the  most  valuable  kind,  the 
chord,  or  distance  between  one  extreme 
point  of  the  curve  and  the  other,  will  mea- 
sure the  sixteenth,  and  sometimes  even 
the  eighth  part  of  an  inch.  This  great 
difference  in  the  arcs,  is  easily  discerna- 
ble  by  every  untaught  eye,  and  more  espe- 
cially deserves  the  notice  of  the  grower. 
He  will  find  specimens  of  the  inferior 
kind,  most  frequent  in  fleeces,  which  have 
been  shorn  from  a  sheep,  the  produce  of 
very  dissimilar  progenitors. 

No  means  have  yet  been  discovered  of 
communicating  this  peculiarly  valuable, 
and  nameless  property  to  wool,  in  which 
it  does  not  naturally  exist.  We  depend 
therefore  upon  the  breeder  alone,  to  pro- 
cure it,  and  are  solicitous  that  in  the  va- 
rious combinations  of  blood,  which  he  is 
continually  forming  in  his  flock,  that  he 
should  not  lose  sight  of  one  of  the  distin- 
guishing characteristics  of  wool,  and  that 
he  should  promote  this  as  well  as  every 
other  valuable  quality  with  the  utmos't 
care.   Tn  a  country  where  the  carcase  of 


woo 


woo 


the  sheep,  is  more  valuable  than  its  pile,  I  whether  the  state  of  his  flock,  the  nature 
and  where  the  cultivation  of  wool  is  at  J  of  the  season,  and  the  climature  of  his 
most,  only  the  secondary  object  of  the  farm,  will  admit  of  it. 
farmer's  care,  it  is  desirable  to  render  the      The  wool  intended  for  the  manufac- 
blood  as  perfect  as  possible,  in  order  that  •  ture  of  worsted  goods  of  any  description, 


we  may  obtain  from  it  without  labour,  i 
even  the  minute  excellencies  of  wool.  J 
But  in  Bueharia,  where  the  shepherd  is 
more  solicitous  about  the  fleece,  than  the 
health,  or  even  the  life  of  his  sheep,  arti- 
ficial means  are  used,  to  produce  some- 
thing like  this  shrivelling  property  deem- 
ed so  valuable  in  these  western  regions- 
There  the  lamb  so  soon  as  it  is  yeaned, 
is  wrapped  in  linen  bandages,  is  exposed 
to  the  sun,  and  has  water  poured  upon  it 
every  day.  As  it  increases  in  size,  the 
fillets  are  gradually  loosened,  yet  so  as  to 
preserve  at  all  times,  a  considerable  pres- 
sure upon  the  wool  By  these  means  the 
pile  is  compressed  to  the  skin,  and  as- 
sumes a  waved  or  damasked  appearance, 
which  is  esteemed  its  supreme  excellen- 
cy. If  it  could  be  supposed,  that  this 
compressure  of  the  fleece,  produces  that 
kind  of  crumpledness,  which  is  consider- 
ed as  an  excellent  quality  in  English 
wool,  the  process  would  be  too  expensive 
and  troublesome  to  our  shepherds,  and 
the  superior  price  lor  which  such  wool 
could  be  sold,  not  adequate  to  reimburse 
them.  But  it  is  more  probable  that  we 
should  And,  if  we  had  opportunities  of 
examining  the  Bucharian  fleece,  that  it 
was  not  at  all  more  adapted  to  the  wool- 
len manufacture,  than  it  would  have 
been,  had  no  such  pains  been  taken  with 
it. 

Most  of  the  wool  produced  at  present 
in  these  kingdoms,  is  too  long  for  the 
perfect  operation  of  the  card,  and  the  first 
process  through  which  it  passes,  after  it 
,  has  left  the  hands  of  the  stapler,  is  cal- 
culated to  shorten  it.  This  is  the  precise 
object  of  the  structure,  and  the  use  of 
the  first  engines,  to  which  the  pile  is  sub- 
mitted. But  the  grower  has  a  much 
more  ready,  and  less  expensive  remedy 
in  his  power  ;  for  he  can  easily  cultivate 
a  race  of  sheep,  whose  coat  shall  be  suf- 
ficiently short  for  the  nicest  purpose,  or 
he  can  shearit  more  frequently  than  once 
a  year,  even  before  it  has  attained  halt 
its  length.  Yet  lie  should  be  very  care- 
ful, how  he  adopts  a  measure  of  this  kind, 
for  he  will  observe  that  the  wool  of  the 
second  clipping  of  one  season,  will  not 
be  exactly  like  that,  which  he  procured 
at  the  other.  Although  somewhat  infe- 
rior in  quality,  in  the  hand  of  an  expert 
manufacturer,  it  may  be  applied  to  ex- 
cellent purposes.  If  inclined  to  try  the 
experiment,  which  is  by  no  means  a  new 
one,  the  shepherd  will  naturally  consider 


is  first  reduced  to  a  proper  state  for  spin- 
ning, by  means  of  the  comb,  an  instru- 
ment very  different  from  the  card,  both 
in  its  structure  and  operation.  It  con- 
sists chiefly  of  a  piece  of  wood,  shaped 
very  much  "like  the  letter  T.  Through 
the  head  or  traverse  part  of  it,  which  is 
generally  about  3  inches  broad,  a  num- 
ber of  very  long  sharp  teeth  are  thrust. 
They  are  finely  tapered,  made  of  well 
tempered  steel,  and  generally  arranged 
in  three  rows,  about  thirty  in  each,  and 
placed  nearly  at  right  angles,  to  every 
part  of  the  wood.  The  handle  of  the 
comb  is  represented,  by  the  perpendicu- 
lar part  of  the  letter.  In  using  this  in- 
strument, the  wool  is  carefully  hung  upon 
the  teeth,  in  such  a  manner  as  to  project 
over  the  front  of  the  head  ;  when  suffici- 
ently filled  and  firmly  fixed,  another  comb 
of  the  same  kind  is  drawn  through  the 
wool,  so  as  to  unravel  and  lay  each  hair 
of  it,  smooth  and  even.  If  we  consider 
the  full  comb,  as  the  human  head  dis- 
graced by  a  quantity  of  neglected,  long 
and  dishevelled  hair,  which  we  reduce  to 
its  natural  and  elegant  order,  we  shall 
have  a  very  just  idea  of  the  operation., 
and  the  use  of  this  instrument,  in  the 
worsted  manufacture.  The  very  name, 
shows  its  origin,  application  and  use. 

But  the  comb  is  used  for  another  pur- 
pose, than  merely  to  lay  the  pile  straight 
and  even  ;  for  the  staple  of  long  wool  com- 
monly contains  a  considerable  number  of 
hairs,  shorter  than  the  generality  of  those 
which  compose  the  fleece,  and  also  a  num- 
ber of  long  ones,  which  are  tied  in  natural 
and  indissoluble  knots, highly  prejudicial, 
when  wrought  into  the  worsted  threads 
These  are  collected  by  the  process  of  com 
bing,  betwixt  the  teeth  of  the  instrument, 
and  by  a  very  curious  and  dexterous  mode 
adopted  to  strip  the  comb  of  its  longer 
pile,  the  workman  leaves  them  there  un- 
til he  has  disposed  of  the  long,  clear  and 
valuable  wool,  extracted  by  his  fingers, 
and  which  from  an  old  English  word  most 
aptly  denoting  the  shape  he  has  given  to 
it,  is  denominated  a  sliver.  When  the  in- 
strument is  cleared  from  the  knots  or 
noil,  it  is  ready  to  repeat  the  operation. 
The  comb  therefore  evidently  requires, 
that  the  wool,  to  which  it  is  applied,  pos- 
sess sufficient  length  to  permit  its  ar- 
rangement upon  the  teeth,  strength  or 
toughness  enough,  to  endure  without 
being  broken  the  muscular  force,  neces- 
sary to  draw  the  instrument  through  it, 


woo 


woo 


and  such  a  degree  of  curvedness,  as  will 
enable  it  to  form  a  close  and  compact 
sliver. 

Even  to  this  day,  the  comb  is  almost 
in  lis  simple  state,very  few  alterations  have 
been  made  either  in  its  structure,or  dimen- 
sions, from  the  time  when  it  was  brought 
into  Europe  ;  and  perhaps  this  is  the  prin- 
cipal reason,  why  we  find  so  little  differ- 
ence in  the  hair  of  long  fleeces,  with  re- 
spect to  its  fineness.  By  far  the  greater 
proportion  of  this  kind  of  wool  produced 
in  England,  when  the  pile  is  accurately 
measured,  varies  only  about  the  two  hun- 
dredth part  of  an  inch.  The  diameter 
of  the  hair,  is  seldom  larger  than  the 
space  denoted  by  an  unit,  when  the  inch 
is  divided  by  six  hundred;  it  is  common- 
ly not  finer  than  that  measure  divided  by 
eight  hundred  ;  a  very  small  quantity  se- 
lected from  fleeces  of  a  shorter  descrip- 
tion, and  submitted  to  the  operation  of 
the  comb,  will  reach  a  thousand.  To 
manufacture  fine  wool  by  means  of  this 
instrument,  its  structure  must  be  less 
coarse^  the  teeth  finer,  shorter  and  placed 
more  nearly  together  ;  the  "  load"  appli- 
ed to  them  considerably  smaller,  and 
should  be  wrought  by  a  less  nervous 
arm.  But  the  manufacturers  of  worsted 
yarn,  are  the  best  qualified  to  decide  up- 
on conjectures  of  this  nature,  and  1  pre- 
sume not  to  trespass  upon  their  peculiar 
province,  being  satisfied  with  expressing 
an  idea  worthy  of  attention,  and  calculat- 
ed I  hope  to  excite  it.  In  general  if  there 
be  a  demand  for  yarn  of  a  finer  quality, 
than  is  commonly  produced,  and  for 
goods  of  a  superior  texture,  manufactu- 
rers, unless  chargeable  with  a  culpable 
want  of  commercial  spirit,  are  always 
ready  to  seek,  and  determined  if  possi- 
ble to  obtain  the  one,  and  to  fabricate  the 
other.  When  this  laudable  zeal  is  ex- 
cited and  encouraged,  the  raw  materials 
necessary  to  the  perfection  of  the  articles 
in  demand,  are  speedily  either  procured 
from  abroad,  or  produced  at  home,  and 
instruments  adapted  to  the  completion 
of  the  fabrics,  are  improved  or  invent- 
ed. 

Yet  it  seems  to  be  peculiarly  difficult, 
to  apply  the  power  of  mechanism,  to  the 
manufacture  of  the  finer  sorts  of  worsted 
yarn,  for  although  long  since  employed 
in  the  fabrication  of  almost  every  article 
of  woollen  goods,  and  even  adopted  with 
considerable  success,  in  spinning  the 
coarser  numbers  of  worsteds,  yet  the 
comb,  and  the  Catherine  wheel,  are  the 
only  instruments  to  this  day  employed,  to 
furnish  the  more  attenuated  threads. — 
Perhaps  the  very  nice  adjustment  of  the 
comber's  muscles,  when  he  draws  the 


sliver,  and  the  adaptation  of  the  spinner's 
motion  to  the  length  and  the  tenuity  of 
the  pile,  when  she  extends  her  thread,  re- 
quire a  dexterity,  the  result  of  habit  ra» 
ther  than  of  judgment,  which  is  not  com- 
patible with  the  unvaried  action  of  an  un- 
intelligent machine. 

It  is  necessary  that  the  combing  wools 
of  our  country  possess  some  degree  of 
curvature,  or  disposition  to  contract  the 
length  of  the  pile,  for  without  it  the  work- 
man could  not  form  his  sliver ;  but  it  is 
not  desirable,  that  this  property  should 
greatly  prevail.  The  reason  why  long 
wool  should  differ  so  essentially  from  the 
pile  of  shorter  fleeces  will  be  easily  un- 
derstood, if  we  attend  the  operation  of 
the  spinning  wheel.  In  twisting  a  wool- 
len thread,  where  the  staple  has  been 
previously  broken,  and  the  fragments  of 
it  in  the  utmost  disorder,  are  united  only 
by  their  natural  hookedness,  the  turning 
of  the  wheel  rolls  them  together  without 
arrangement,  and  when  placed  in  every 
possible  direction.  But  in  spinning  a 
worsted  thread,  where  every  hair  has 
been  previously  disposed  by  the  side  of 
others,  in  the  most  regular  order,  the  pile 
is  drawn  out  in  the  direction  of  its  length, 
every  single  hair  being  parallel  to  all  those 
which  lie  near  it,  and  is  twisted  in  a  spi- 
ral form,  something  like  the  threads  of  a 
compound  screw.  If  those  hairs  contract- 
ed their  length,  in  a  considerable  degree, 
they  could  not  be  correctly  arranged  nor 
drawn  out  in  the  regular  order,  which 
the  work  requires,  but  would  be  twisted 
into  the  thread,  in  an  irregular  and  crum- 
pled form  ;  a  circumstance  injurious  to 
the  yarn,  and  to  the  goods  which  are  made 
from  it. 

This  general  account  of  the  different 
process  through  which  wool  passes,  in 
the  first  stages  of  the  manufacture,!  trust, 
will  be  intelligible  to  every  one,  and  suf- 
ficient to  convince  the  grower,  that  the 
good  qualities  of  the  fleece  are  not  of  a 
capricious  kind;  that  wool  cannot  be  em- 
ployed arbitrarily,  to  any  purpose  which 
the  manufacturer  may  choose,  but  that 
nature  points  out  its  peculiar  destination  ; 
that  the  workman  is  obliged  to  take  the 
raw  material  with  all  its  defects,  and  ap . 
ply  it  to  uses  for  which  it  is  best  adapt- 
ed, although  he  observe  in  it  qualities 
which  injure  his  fabrics,  and  lament  that 
it  is  not  possible  for  his  utmost  skill  and 
industry,  to  counteract  their  effects.  Thus 
situated,  he  looks  anxiously  to  the  grow- 
er for  assistance,  as  to  the  only  person 
who  can  change  the  properties  of  the 
fleece,  and  produce  a  perfect  staple,  most 
resonably  supposing  that  his  wants  should 
be  attended  to,  and  his  wishes  gratified. 


woo 


woo 


Perhaps  the  independent  spirit  of  the  ma- 
uufacturer  might  be  mortified,  if  we  hint- 
ed,  that  he  is  the  workman  of  the  shep- 
herd, or  we  could  ask  the  farmer,  if  he 
be  not  extremely  solicitous  to  sow  good 
seed,  in  order  that  he  may  furnish  the 
miller  and  the  meal-man,  with  a  prime 
article,  while  he  is  reproachfully  careless 
of  the  quality  of  that  commodity,  with 
which  he  supplies  the  comber,  the  spin- 
ner, and  the  weaver. 

The  length  of  pile  suited  to  the  comb, 
is  upwards  of  four  inches.  The  hose- 
trade  require  a  considerable  share  of  that, 
which  measures  from  four  inches  to  eight, 
and  the  longer  kind,  is  usually  destined 
to  the  fabrication  of  worsted  yarn ;  an  ar- 
ticle which  admits  of  very  great  variety, 
in  the  mode  of  its  manufacture.  The 
shorter  staple  is  applicable  to  woollen 
goods,  of  almost  every  description,  which 
beside  the  whole  quantity  of  this  sort  of 
fleeces  produced  at  home,  require  very 
large  importations  from  abroad;  and  no 
inconsiderable  quantity  of  that  pile,  which 
has  been  grown  tothe  length  of  combing 
wool,  is  submitted  to  the  operation  of  the 
card.  'Tis  chiefly  that  however,  which 
possesses  the  contracting  property  in  too 
great  a  degree ;  which  is  too  weak  for 
the  comb,  or  is  used  to  produce  articles 
requiring  a  long  and  well  raised  knap. 

Graziers  are  able  to  increase  the  length 
of  staple,  by  various  means.  Most  of 
them  having  been  mentioned  already,it  will 
be  sufficient  here  barely  to  repeat  them. 
The  management  of  the  breed  is  not 
only  the  most  natural  and  easy  method, 
but  that  also  which  is  most  usually  adopt- 
ed. Its  effects  are  more  permanent  than 
others,  which  are  sometimes  resorted  to, 
but  less  pure  from  deleterious  influence ; 
for  it  is  not  unfrequently  observed,  that 
the  ram  communicating  to  his  offspring, 
an  increased  length  of  staple,  gives  to  it 
also  a  coarser  pile.  Feeding  the  sheep 
upon  the  richer  grasses,  upon  turnips  and 
oil  cake,  thus  forcing  both  the  carcase 
and  the  fleece,  seems  to  be  a  method  of 
increasing  the  length  of  wool,  free  from 
contaminating  influence,  but  requires  the 
animal  to  be  constantly  supported,  even 
to  the  point  of  luxurious  feeding ;  and 
the  effects  of  the  system,  remain  no  long- 
er than  it  is  continued.  Another  method 
pi  increasing  the  length  of  the  staple, 
pointed  out  by  nature,  but  seldom,  per- 
haps never  adopted,  with  this  particular 
design,  is  to  keep  the  wool  upon  the  back 
of  the  sheep,  through  two  whole  years  ; 
it  requires  only  care,  that  the  animal  be 
not  injured,  by  cold  or  by  hunger,  dur- 
ing the  period  that  the  fleece  is  growing. 


The  pliability  of  wool  is  another  of 
those  qualities  in  the  staple,  which  de- 
serve the  closest  attention  of  the  shep- 
herd, being  esteemed  by  the  manufactu- 
rer, an  essential  properly.  All  inflexible 
and  brittle  substances,  are  evidently  unfit, 
for  many  of  the  operations,  through  which 
wool  must  pass,  before  it  can  be  brought 
to  that  finished  state  of  manufacture, 
which  is  intimately  connected  with  the 
comfort  and  the  elegance  of  life.  It  is 
impossible  to  produce  from  them  a  long 
extended  thread,  whose  tenuity  and  com- 
pactness shall  fit  it  for  the  action  of  the 
loom,  the  fulling-mill  and  the  press.  In- 
deed for  many  articles  of  the  woollen  ma- 
nufacture, the  pile  cannot  possess  too 
much  pliability,  if  it  does  not  lose  that 
tendency  to  contract  its  length,  and  as- 
sume a  crumpled  form,  which  we  have 
already  described,  as  one  of  the  best  qua- 
lities of  the  shorter  staples.  In  the  finer 
specimens  of  the  Spanish  wool,  these  two 
properties  are  admirably  adjusted,  the 
curvature  of  the  pile  is  most  delicate  and 
true,  its  plastic  quality  is  extolled,  to  al- 
most proverbial  triteness  ;  but  the  staple 
of  most  British  fleeces,  is  complained  of 
as  stubborn  and  elastic,  counteracting  the 
effects,  which  the  spinning  wheel  should 
produce,  and  rendering  the  thread  loose 
and  bristly.  Yet  it  must  be  recollected 
that  woollen  articles,  require  a  great  va- 
riety in  the  degrees  of  elasticity,  possess- 
ed by  the  wool,  from  which  they  are  made. 
Those  designed  to  withstand  the  extreme 
rigours  of  the  winter  season,  such  as  blan- 
kets and  fearnoughts,as  well  as  shags,and 
some  sorts  of  carpeting,  require  a  very 
large  proportion  of  it,  such  as  will  enable 
the  workman  to  form  a  long  and  swelling 
knnp  ;  but  in  the  finer  and  thinner  fabrics, 
whose  surface  is  intended  to  be  highly 
polished,  a  great  degree  of  elasticity  is 
very  injurious.  It  always  causes  these 
substances  to  feel  hard  and  prickly,  be- 
cause the  ends  of  the  hair  starting  from 
the  body  of  the  thread,and  projecting  from 
the  surface  of  the  cloth,  affect  the  sense 
of  feeling  exactly  like  an  immense  num. 
ber  of  short  acute  points  fixed  there.  In 
finishing  goods  of  almost  every  descrip- 
tion, both  of  woollens  and  worsteds,  ex- 
cepting those  already  mentioned,  the  re- 
duction of  this  extreme  elasticity,  is  one 
object  among  others,  of  the  workman's 
care.  For  this  purpose  lie  employs  the 
shears,  the  singing  stoves  and  the  press, 
with  its  heated  plates,  and  is  able  by  these 
aids  united  with  great  industry,  to  form 
a  surface  smooth,  soft  and  glossy  ;  but 
the  effect  he  produces  upon  stongly  elas- 
tic wool  is  little  more  than  temporary, 


woo 


woo 


since  moisture  restores  its  former  stub- 
bornness, and  deprives  it  of  that  gloss 
which  had  been  impressed  upon  it.  The 
effect  of  heat  upon  wool  is  very  singular, 
for  when  applied  in  a  moderately  high  de- 
cree, it  seems  to  furnish  the  pile  with  the 
power  of  expanding  itself,  as  though  it 
exejted  a  mutual  repulsion  betwixt  the 
hairs  of  which  the  staple  is  composed,  and 
is  often  made  use  of  in  the  processes  of 
the  woollen  and  worsted  manufactures, 
with  great  advantage;  and  when  united 
with  the  pressure,  it  serves  to  fix  the  pile 
in  the  artificial  direction  which  is  given  to 
it ;  an  effect  familiarly  illustrated  by  the 
curling  irons  of  the  friseur.  The  adjust- 
ment of  this  neglected  property  may  be 
recommended  to  the  wool-grower's  atten- 
tion with  great  propriety,  because  if  we 
may  judge  from  some  of  the  fleece  pro- 
duced by  the  most  celebrated  breeds,  it  is 
as  much  connected  with  the  blood  of  the 
animal  as  any  other  quality,  which  can  be 
communicated  from  the  parents  to  the 
offspring,  and  is  a  very  weighty  consider- 
ation when  we  are  estimating  the  perfec- 
tion of  the  pile. 

The  short  account  given  before  of  the 
manner  in  which  wool  is  combed,  and  of 
the  effect  which  the  card  is  intended  to 
produce  upon  it,  will  convey  to  those  who 
have  been  familiar  with  these  processes, 
some  idea  of  the  value  of  a  proper  de- 
gree of  toughness  in  the  pile.  If  the  sta- 
ple be  weak  and  easily  broken  asunder, 
it  will  not  be  able  to  endure  the  force 
which  is  necessary  to  drag  the  comb 
through  it.  Breaking  to  pieces  in  the 
operation,  the  fragments  collect  in  the 
instrument,  and  form  only  a  noil,  an  arti- 
cle of  no  use  in  the  fabrication  of  worst- 
eds. The  grazier  may  easily  perceive 
when  his  combing  wool  is  too  weak,  for 
if  the  staple  break  when  strongly  pulled 
with  the  fingers  of  both  hands,  he  may  al- 
ways conclude  that  it  is  ill  adapted  to  the 
manufacture  of  worsteds,  and  most  com- 
monly rendered  totally  unlit  for  it.  If  he 
attempt  to  promote  the  growth  of  a  su- 
perior kind  of  long  wool,  it  is  of  the  utmost 
consequence  that  he  notice  the  strength 
and  soundness  of  the  staple ;  for  if  the 
fleeces,  which  he  has  cultivated  with 
care,  and  whose  length  of  pile  he  has  in- 
creased, be  not  sufficiently  strong  for  the 
comb,  he  has  not  only  failed  to  attain  his 
object,  but  has  greatly  injured  his  wool. 
Peculiar  care  is  necessary  also,  when  the 
proprietor  of  along-wooled  flock  attempts 
to  render  the  pile  finer  by  a  selection  of 
rams  carrying  a  smaller  fleece,  for  there 
are  only  few  breeds  in  the  kingdom, 
which  yield  fleeces  at  once  fine,  and  suffi- 
ciently strong  for  the  comb    A  sensible 


wool -stapler,  who  has  long  observed  the 
English  fleece,  and  whose  judgment  and 
candour  I  have  heard  spoken  of  among 
spirited  agriculturists,  with  the  respect 
they  deserve,  writing  upon  this  subject, 
complains  that  by  the  improvement  of 
sheep  in  the  counties  of  Huntingdon,  Nor- 
thampton, Leicester,  and  Lincoln,  the 
qualities  of  the  staple  have  been  greatly 
injured,  that  the  wool  is  rendered  too 
weak  for  the  old  established  manufac- 
tures, and  adds,  "  this  is  an  evil  that  must 
soon  remedy  itself,  for  deep  strong  wool 
will  become  the  most  valuable." 

But  on  the  contrary,  the  carding  wools 
ought  not  to  possess  too  great  a  degree 
of  strength  or  toughness,  because  the 
process  through  which  they  pass,  is  de- 
signed to  break  the  pile  into  small  frag- 
ments, which  is  by  no  means  accomplish- 
ed when  the  strength  of  the  hair  is  suffi- 
cient to  endure  the  force  applied  to  it 
with  the  card,  and  enables  it  by  passing 
through  the  interstices  of  the  teeth,  to 
avoid  their  proper  action.  Nor  should  it 
be  supposed  that  the  shorter  pile  cannot 
be  too  tender,  for  it  is  sometimes  found 
so  decayed  as  to  be  broken,  when  passing 
through  the  engine,  more  minutely  than 
the  natural  hookedness  of  the  staple  will 
admit  of,  it  is  then  easily  dissipated  by 
the  motion  of  the  cylinders,  and  wasted  ; 
nor  will  the  cloth,  unless  the  wool  of 
which  it  is  made  possess  some  con- 
siderable toughness,  endure,  without 
injury,  the  violent  strokes  of  the  fulling 
mill. 

No  technical  name,  I  believe,  has  yet 
been  given  to  the  felting  quality  of  the 
fleece,  although  it  has  been  long  applied, 
to  useful  purposes,  and  is  of  essential  im- 
portance in  the  fabrication  of  many  kinds 
of  woollen  goods.  It  is  the  basis  upon 
which  the  hat  manufacture  depends 
among  ourselves,  and  has  for  many  ages 
been  applied  abroad  to  the  production  of 
pieces  of  domestic  furniture.  In  the  fa- 
brication of  worsted  goods  it  is  not  em- 
ployed, nor  is  it  necessary  in  the  manu- 
facture of  stockings,  blankets,  baize,  flan- 
nels,  nor  any  other  article  not  submitted 
to  the  action  of  the  fulling  mill.  In  some 
of  them,  when  made  of  wool,  in  which  it 
abounds,  the  housewife  finds  great  incon- 
venience, and  complains  that  her  stock- 
ings and  her  flannels  become  too  small 
for  the  wearer.  From  the  different  modes 
of  manufacturing  these  articles,  we  may 
conclude,  that  in  general  the  felting  qua- 
lity is  a  valuable  one,  in  almost  every  des- 
cription of  fine  and  short  stapled  fleeces, 
and  that  it  is  not  desirable  in  the  greater 
part  of  the  longer  and  coarser  wools — 
There  are  few  circumstances,  in  which 


woo 


woo 


the  breeds  of  sheep,  most  commonly  met 
with  in  these  islands,  differ  more  from 
each  other,  than  in  their  power  of  yield- 
ing a  fleece,  which  possesses  fully,  or  is 
partially  destitute  of  this  valuable  proper- 
ty. It  may  be  described  as  a  tendency  in 
the  pile,  when  submitted  to  moderate 
heat,  combined  with  moisture,  to  cohere 
tog-ether  and  form  a  Compact  and  pliable 
substance.  But  this  property  does  not 
belong-  exclusively  to  the  pii'1  of  the  sheep, 
the  hair  of  other  animals,  particularly  the 
camel,  the  dromedary,  the  goat,  and  the 
beaver,  are  known  to  possess  it  in  a  high 
degree;  perhaps  few  of  the  shorter  furs 
are  entirely  destitute  of  it,  although  the 
longer  hair,  and  that  which  has  a  polish- 
ed and  hard  surface,  with  a  degree  of 
brittleness,  exhibit  only  slight  symptoms 
of  its  existence.  I  have  never  yet  traced 
it  in  the  hair  of  the  human  head,  except 
in  the  disordered  state  of  it,  common  in 
Poland,  nor  in  that  which  is  cut  from  the 
necks  and  tails  of  horses,  nor  in  the  bris- 
tles of  the  hog,  although  each  of  them 
have  been  observed  minutely  in  the  grow- 
ing, the  raw,  and  manufactured  state. 

Among  the  animals  whose  furs  possess 
this  valuable  property,  the  sheep  is  most 
distinguished ;  and  if  we  draw  the  con- 
clusion from  the  quantity  of  felts  used 
through  all  parts  of  the  East,  and  the  easy 
method  in  which  some  of  them  are  form- 
ed, it  seems  that  the  wool  of  the  Western 
Asia  is  not  destitute  of  it ;  that  of  France 
possesses  it  in  a  distinguished  measure, 
and  the  envied  produce  of  Spain,  surpas- 
ses that  of  neighbouring  countries  in  this, 
as  in  most  other  excellencies.  From  the 
fleeces  of  England,  those  have  been  select- 
ed as  the  best  adapted  to  the  lulling  mill, 
Avhich  are  obtained  from  the  Norfolk*  the 
Morf  and  the  Cheviot  breeds  of  sheep; 
while  the  South -Downs  have  been  gene- 
rally descried  as  producing  a  kind  of  wool, 
notwithstanding  ah  that  has  been  said  in 
their  favour,  notoriously  deficient  at  least 
of  this  good  quality.  Perhaps  it  may  be 
owing  m  some  measure  to  the  chalkiness 
of  the  land  upon  which  these  sheep  pas- 
ture, for  we  have  observed  that  both  these 
and  the  Wiltshire  breed,  when  removed  to 
different  soils,  produce  a  wool,  which 
thickens  in  the  fulling  mill,  alt  hough  it 
proceeds  more  slowly  in  the  operation 
than  the  pile  of  some  other  families.  We 
must  not  conclude  from  this  circumstance, 
that  the  dilference  observed  in  the  felting 
quality  of  fleeces,  is  entirely  owing  to  the 
land,  because  we  find  upon  soils  known 
not  to  be  injurious  to  wool,  different  kinds 
of  sheep,  whose  fleeces  do  not  possess 
this  quality  in  an  equal  degree.  Graziers 
•night  easily  ascertain  to  what  cause  the 


dissimilarity  is  owing ;  and  surely  when 
the  South-Down  breed  is  diffusing  itself 
so  widely  over  the  country,  it  becomes 
the  breeders  of  Sussex  to  wipe  off  every 
reproach  from  their  stock. 

The  felting  quality  of  wool  is  not  evi- 
dent to  the  eye ;  and  though  there  be 
some  very  general  appearances,  which 
indicate  the  existence  of  the  property,  or 
its  absence,  yet  they  are  so  vague,  that  the 
best  judges  of  wool  consider  this  as  a 
point  to  be  ascertained  only  by  trial.  The 
application  of  moisture,  warmth  and  pres- 
sure, is  the  most  usual  mode  of  bringing 
the  quality  into  action.  Without  the  aid 
of  the  first,  it  remains  perfectly  dormant ; 
the  two  latter  are  employed  to  quicken 
the  process.  The  tendency  of  thread,  of 
almost  every  description,  to  contract  its 
length,  as  it  imbibes  moisture,  has  not 
only  been  generally  known,  but  some 
kinds  are  considered  as  acting  so  regu- 
larly, and  so  susceptible  even  of  the 
s lightest  alteration,  in  the  cause  which  af- 
fects them,  as  to  authorize  their  applica- 
tion to  the  most  accurate  purposes  of  Na- 
tural Philosophy.  Hut  the  woollen  thread 
possesses  the  quality  of  retaining  its  con- 
traction, after  the  cause  which  produced 
it  has  ceased  to  operate,  while  most 
others,  such  as  lines  of  catgut,  horse  hair, 
iinen,  hemp,  and  cotton,  assume  their 
former  length.  We  know  too  little  at 
present  to  enable  us  to  assign  the  cause  of 
this  permanent  contraction  ;  but  conjec- 
ture that  it  is  owing  to  the  particles  of 
the  thread,  which  are  brought  into  actual 
contact  with  each  other,  cohering  exactly 
upon  the  same  principle  as  the  leaden 
bails  do  in  the  common  experiment  so 
often  exhibited  in  lectures  upon  Natural 
Philosophy)  to  illustrate  the  attractive 
power  of  bodies.  In  this  experiment,  it 
is  necessary  to  clear  the  lead  from  all  fo- 
reign substances,  at  least  in  the  points 
where  the  balls  touch  each  other  ;  but  in 
the  felting-  of  wool,  on  the  contrary,  it  is 
equally  necessary  to  use  some  fluid,  which 
intimately  mingles  itself  with  the  pile,  and 
promotes  the  attraction,  as  oil  does  when 
infused  for  the  same  purpose,  between 
two  plates  of  glass.  Moderate  warmth 
evidently  assists  the  process;  but  why  it 
does  so,  and  how  it  acts,  are  in  a  great 
measure  unknown.  The  degree  of  heat 
required  to  make  the  felting  property  act 
with  its  utmost  force,  is  considerably  be- 
low the  boiling  point  of  water  ;  a  higher 
temperature  loosens  the  texture  of  the 
thread,  and  increases  the  elasticity  of  the 
hair,  thus  giving  it  a  disposition  to  start 
from  the  substance  of  the  cloth  and  spoil 
its  surface.  Pressure  seems  to  be  useful 
by  bringing  a  greater  number  of  point  s 


woo 


woo 


into  contact,  and  by  divesting  the  thread  ] 
of  the  air  which  is  lodged  in  its  insterti-  i 
ces.    But  so  little  is  known  of  the  pro-  I 
ceedings  of  nature  in  the  operation  of 
felting*,  that  the  manufacturer  who  would 
institute  judicious  experiments,  superin- 
tend them  with  care,  and  publish  the  re- 
sults, would  perform  a  service  useful  to 
his  country. 

The  mode  of  bringing  this  latent  pro- 
perty into  action,  has  not  been  always  the 
same.  In  the  ruder  ages,  it  seems  to  have 
been  excited  by  the  pressure  obtained 
from  the  weight  of  the  human  bod}-;  the 
cloth  in  its  rough  state  being  placed  be- 
neath the  feet  of  the  workmen,  they  con- 
tinued to  trample  upon  it  until  sufficient- 
ly thickened.  Hence  the  person  engaged 
in  this  employment  was  called  a  waulker, 
or  walker  of  cloth  ;  and  the  machine  af- 
terwards introduced  to  answer  the  same 
purpose,  was  denominated  a  waulking 
mill.  Mrs.  Guthrie,  in  her  tour  through 
the  Taurida,  informs  us  that  the  Tartars 
still  use  the  patriarchal  mode.  Spread- 
ing two  or  three  layers  of  "  combed" 
wool  moistened,  "  they  tread  it  under  foot 
for  a  few  hours,  and  form  their  carpets 
without  the  aid  of  the  loom,  or  the  modern 
invention  of  cylinders."  Yet  this  learned 
lady,  who  during  her  journey  collected 
a  great  deal  of  information,  is  perhaps 
mistaken  when  she  describes  the  wool  as 
being  "combed,"  because  this  process 
was  first  adopted  long  since  the  days  of 
the  patriarchs,  and  supposes,  a  knowledge 
of  the  arts  totally  inconsistent  with  the 
spirit  of  her  remarks.  If  the  wool  i.e 
prepared  by  any  instrument;  and  not  by 
the  fingers  alone,  it  is  probably  done  by 
means  of  the  wild  teasel,  at  least  we  have 
reason  to  suppose  so,  if  that  plant  is  to 
be  found  there.  The  first  improvement 
in  the  art  of  fulling  cloth,  I  apprehend, 
consisted  in  substituting  a  sitting  posture 
in  the  workpeople  for  an  erect  one ;  there- 
by enabling  them  to  perform  the  work 
more  rapidly  and  with  greater  ease.  Mr. 
Pennant,  the  only  one  that  I  know  of,  who 
has  given  an  account  of  the  process  in 
this  stage,  saw  it  performed  in  the  isle  of 
Sky,  during  his  voyage  to  the  Hebrides. 

"On  my  return  from  lieinn-shuardal, 
he  says,  I  am  entertained  with  a  rehear- 
sal, I  may  call  it,  of  the  Luagh  or  walking 
of  cloth  ;  twelve  or  fourteen  women  divi- 
ded into  two  equal  numbers,  sit  down  on 
each  side  of  a  long  board,  ribbed  length- 
ways, placing  the  cloth  on  it.  First,  they 
begin  to  work  it  backwards  and  forwards 
with  their  hands,  singing  at  the  same 
time ;  when  they  have  tired  their  hands, 
every  female  uses  her  feet  for  the  same 
purpose,  (still  sitting)  and  six  or  seven 


pair  of  naked  feet  are  in  the  most  violent 
agitation,  working  one  against  the  other; 
as  by  this  time  they  grow  very  earnest  in 
their  labours,  the  fury  of  the  song  rises, 
at  length  it  arrives  to  sueh  a  pitch,  that 
without  breach  of  charity,  you  would  ima- 
gine a  troop  of  female  demoniacs  to  have 
been  assembled.  The  subject  of  the  song 
on  this  occasion  is  sometimes  love,  some  - 
times panegyric,  and  often  a  rehearsal  of 
the  deeds  of  the  ancient  heroes,  but  com- 
monly all  the  tunes  are  slow  and  melan- 
choly." This  author  gives  an  expressive 
plate  of  the  Luaghad,  but  when  he  calls 
it  "  a  substitute  for  the  fulling  mill,"  1  ap- 
prehend his  language  is  not  quite  cor- 
rect. 

The  fulling  mill  was  probably  first 
brought  into  England  by  the  Flemings, 
and  does  great  credit  to  the  age  when  it 
was  introduced,  both  by  the  simplicity  of 
its  structure,  and  the  perfection  with 
which  it  performs  the  task  assigned  to  it- 
While  many  boasted  improvements,  which 
have  been  introduced  since  that  period, 
are  again  laid  aside,  this  machine,  like  a 
venerable  old  man,  stands  amidst  modern 
ones,  the  long  tried  faithful  servant,  the 
admiration  of  his  juniors,  and  boasts,  that 
he  can  perform  "the  appointed  task  of 
every  day  with  as  much  vigour  as  in  his 
prime  This  ancient  engine  deserves  our 
regard,  since  it  was  the  first  combination 
of  mechanical  power,  applied  to  the  wool- 
len manufacture,and  more  generally  adap  - 
ted  through  several  centuries  in  every 
country  of  civilized  Europe,  than  any 
other  machine  which  can  be  mentioned. 
Something,  though  but  little,  has  been 
done  to  metamorphose  its  appearance  and 
action,  but  the  alterations  which  have 
been  made  in  it,  when  compared  with 
those  observable  in  other  engines,  are  tri- 
fling, I  had  almost  said  contemptible. — 
Yet  when  a  second  Arkwright  shall  arise, 
and  apply  to  it  his  wonderful  genius,  per- 
haps in  some  following  age,  the  fulling 
mill^  will  assume  an  appearance  as  differ- 
ent from  that  which  it  exhibits  at  present, 
and  effect  its  purpose  in  a  manner  as  va- 
ried, as  the  modem  jenny  does  from  the 
old  spinning  wheel,  as  the  carding  ma- 
chine, with  its  revolving  cylinders,  and  ad- 
justed variation  of  motion,  does  from  the 
petty  instrument  formerly  wrought  by  the 
hand. 

In  the  last  age,  the  operation  of  the  ful- 
■  ling  mill  was  very  laborious  and  tedious. 

A  piece  of  cloth  was  then  submitted  to  it 
I  for  thirty  successive  hours,  whereas  now 
:  it  is  often  rendered  sufficiently  thick  in 
,  seven  or  eight ;  an  instance  of  economy 
:  in  the  use  of  time  and  labour,  which  au- 
gurs well  for  the  interest  of  the  manufac  - 


woo 


woo 


Hirer.  This  remarkable  alteration  must  be 
attributed  partly  to  improvement,  in  the 
mode  of*  spinning-,  to  the  superior  skill  of 
workmen,  both  in  the  loom  and  at  the  mill, 
to  the  selection  of  materials  possessing  the 
lelting  property  in  the  strongest  degree, 
to  the  general  taste  for  thinner  cloth,  and 
perhaps  to  the  improvement  of  the  raw 
material.  Yet  it  must  be  confessed  that 
the  wool-grower  has  contributed  less  to 
*he  public  benefit  arising  from  this  source, 
than  most  other  persons  connected  with 
the  manufacture.  If  he  be  anxious  to  pro- 
mote the  growth  of  fleeces,  in  which  the 
felting  quality  greatly  prevails,  1  should 
recommend,  from  the  little  knowledge  at 
present  possessed,  that  he  attend  closely 
to  the  supply  of  natural,  rich  and  nutri- 
tious yolk,  which  the  pile  receives  while 
growing — that,  \\  h^re  the  soil,  or  the  cli- 
mate of  his  farm,  will  not  admit  the  pro- 
duction of  a  sufficient  quantity,  he  should 
seek  for  a  substitute,  adopting  the  best 
which  presents  itself;  and  to  excite  his  at- 
tention, shall  only  repeat  the  expressive 
language  of  the  clothier,  who  commonly 
asserts  "  that  cloth  is  either  made  or  mar- 
red at  the  mill." 

When  enumerating  the  essential  qua- 
lities of  fleeces,  we  must  not  forget  the 
softness  of  the  pile  ;  for  every  person 
whose  knowledge  of  the  manufactured  ar- 
ticle is  derived  chiefly  from  the  purchase 
of  a  coat  or  two,  in  the  course  of  a  year, 
attends  more  particularly  to  the  colour  of 
the  cloth,  and  the  effect  produced  upon 
the  sense  of  feeling  than  to  any  other  cir- 
cumstances. Indeed  the  softness  of  the 
face,  which  a  piece  presents  to  him,  is 
frequently  considered  as  a  test  of  good- 
ness in  the  materials  from  which  it  is 
made.  The  manufacturer  therefore,  al- 
ways attentive  to  the  public  taste,  endea- 
vors to  produce  by  his  loom  a  texture 
distinguishable  for  its  silky  smoothness  ; 
a  quality  which  the  skilful  dresser  at- 
tempts to  heighten  by  every  favourable 
circumstance  he  observes,  either  in  the 
piece  or  the  operations  of  nature.  But 
the  utmost  skill  can  be  only  of  little  avail 
where  the  pile  is  naturally  hard  The 
pieces  which  are  made  from  it,  are  inva- 
riably rejected,  whether  they  be  present 
ed  to  the  purchasers  in  the  halls,  the  mer- 
chant's warehouse,  or  the  retailer's  shop  - 
while  those  made  from  wool  of  a  softer 
texture  find  a  readier  sale,  and  obtain  a 
greater  price.  The  difference  of  wool 
with  respect  to  the  quality  under  consider- 
ation, is  really  astonishing ;  some  is  so 
hard  and  hairy,  that  goods  fabricated  from 
it  almost  prick  the  hand  j  an  effect  always 
disgusting,  and  never  completely  counter- 
acted, even  in  articles  where  the  mode  of 


manufacturing  and  of  finishing  them,  most 
successfully  conceals  it.  Most  persons 
when  speaking  of  this  quality,  and  ex- 
pressing it  by  the  term  already  used,  con- 
nect  with  it  "an  idea  of  that  effect,  which 
silk  produces  upon  the  sense  of  feeling  ; 
but  there  are  few  who  seem  as  though 
they  intended  to  convey  by  the  same  term 
an  idea  of  that  sensation  which  is  the  ef- 
fect of  down  or  cotton  upon  the  touch. — 
The  first  arises  from  the  peculiar  smooth- 
ness of  the  hair,  the  last  from  the  little 
resistance  which  it  makes  to  pressure. 

This  silky  softness,  like  most  other 
good  qualities  of  the  fleece,  depends  very 
much  upon  the  breed  of  the  sheep  and  the 
quantity  of  yolk  which  they  constantly  af- 
ford. Some  districts  yield  a  staple  pecu- 
liarly smooth  and  delicate,  in  which,  like 
the  celebrated  wool  of  Shetland  and  Vigo, 
softness  forms  the  distinguishing  charac- 
teristic. The  Spaniard,  than  whom  few 
can  boast  of  a  softer  fleece,  is  so  tho- 
roughly aware  of  the  value  of  this  proper- 
ty, and  the  means  likely  to  promote  it, 
that  he  not  only  attends  with  peculiar  care 
to  the  breed  which  travels  to  the  moun- 
tains, but  before  shearing,  encloses  the 
sheep  in  sudatories,  in  order  to  saturate 
and  soften  the  pile  with  yolk.  And  even 
among  ourselves,  the  softest  pile  is  col- 
lected, if  the  breed  be  similar,  from  flocks 
which  have  been  kept  in  good  condition,on 
loamy  soils,  and  into  whose  fleeces  the 
shepherd  has  been  careful  to  admit  no  par- 
ticles of  absorbent  earth.  In  the  course 
of  business,  I  once  met  with  a  small  par- 
cel of  wool,  collected  from  sheep  of  West- 
moreland, which  had  been  smeared,  ac- 
cording to  the  custom  of  that  country, 
with  a  mixture  of  tar  and  grease,  in  the 
autumn,  driven  into  Huntingdonshire,  and 
pastured  during  the  winter  and  vernal 
months,  upon  the  warmer  soils  of  that 
southern  district.  In  this  part  of  the 
kingdom  tarred  wool  was  quite  a  novel  ar- 
ticle, and  the  impossibility  of  abstracting 
all  the  filth  from  the  upper  part  of  the 
staple,  by  the  common  mode  of  working 
it,  alarmed  the  proprietor,  who  like  an  ho- 
nest man,  wound  the  fleece  with  the  leech 
outwards,  a  practice  neither  common  in 
that  country,  nor  adopted  by  the  same 
farmer  in  the  other  part  of  his  parcel,  in 
order  that  he  might  more  effectually  con- 
ceal the  dirt.  These  rejected  fleeces  how- 
ever, which  passed  from  hand  to  hand  be- 
cause unfit  to  be  mingled  with  the  com- 
mon pile  of  the  neighbourhood,  were  final- 
ly sorted  in  my  possession,  and  contained 
the  softest  wool  of  English  growth  that  I 
ever  examined.  Its  staple  was  perfectly 
free  from  kemps  and  wild  hair,  so  c'om- 
mon  upon  the  backs  of  northern  sheep, 


woo 


woo 


and  it  was  much  finer  lhan  the  wool  usu- 
ally found  either  in  Westmoreland  or 
Huntingdonshire :  but  too  long  tor  the 
card,  and  too  ttnder  for  the  comb  ;  in 
other  respects  it  possessed  almost  eveiy 
valuable  quality.  No  means  presented 
themselves  of  ascertaining  the  precise  ef- 
fect produced  by  the  change  of  climate, 
food  and  treatment,  which  these  sheep 
had  most  probably  experienced  ;  but  the 
facts  just  stated,  lead  us  to  conjecture 
that  it  was  very  considerable,  and  extreme- 
ly beneficial  I  hey  induce  us  to  wish  that 
the  experiment  were  repeated  with  more 
accurate  attention  to  the  flock,  especially 
as  the  increase  of  softness  in  the  southern 
wools,  is  most  sincerely  to  be  wished. 

Enough  has  been  said  already  upon  tin 
colour  of  wool  to  illustrate  the  advantage 
of  perfect  whiteness;  but  it  seems  desira- 
ble that  the  appearances  in  British  fleeces 
inconsistent  with  this  excellency,  should 
be  more  minutely  pointed  out,  in  order 
that  the  grower  may  observe  and  correct 
them.  The  yolk  often  leaves  in  the  pile  a 
deep  tint  of  yellowness,  which  ought  to 
be  avoided,  if  it  be  possible  to  prevent  it, 
without  injury  to  the  staple.  A  sensible 
French  chemist  made  some  experiments, 
connected  with  the  art  of  bleaching  wool, 
but  did  not  extend  them  far  enough  to 
attain  any  very  important  information,  and 
contented  himself  with  refei  ring  to  the 
well-known  mode  of  storing  cloth  by  the 
fumes  of  sulphur ;  nor  has  any  other  per- 
son discovered  a  process  applicable  to  the 
unwroughx  staple,  by  which  it  may  be 
rendered  perfectly  colourless.  We  turn 
there-lore  to  the  only  one  who  can  dispose 
the  qualities  of  wool  as  he  pleases,  and 
solicit  attention.  In  some  sorts  of  wool, 
which  possess  valuable  qualities  in  the 
highest  degree,  and  whose  yolk  has  evi- 
dently been  copious  and  rich,  we  see  no 
unfavorable  tints,  and  are  induced  to  sup- 
pose that  perfection  of  colour  may  be  at- 
tained without  sacrificing  any  good  quali- 
ty of  the  staple.  Even  in  wool  reputed 
white,  we  observe  some  smaller  deviations 
from  that  clearness  which  is  desirable  in 
all  fleeces,  and  besides  the  yellowness  just 
mentioned,  as  the  effect  of  the  yolk,  flee- 
ces very  frequently  possess  from  the  con- 
stitution  of  the  sheep,  or  the  nature  of 
the  soil  whereon  it  feeds,  a  blue,  a  brown, 
or  a  redish  tinge.  Very  commonly  grey 
hairs  are  mingled  with  the  white  ones,  so 
intimately  as  to  escape  the  notice  of  the 
most  penetrating  eye  until  the  pile  be 
scoured ;  an  operation  not  always  per- 
formed before  it  is  made  into  cloth,  when 
the  manufacturer  sometimes  finds  that 
it  is  not  fit  to  be  imbued  with  the  more 
delicate  tints,  and  on  that  account  not 

VOL.  II. 


adapted  to  the  purposes  for  which  he  de. 
signed  it  Perhaps  mort  than  half  the 
quantity  of  short  wool  produced  in  En- 
gland is  not  free  from  ibis  detect,  a  cir- 
cumstance which  should  lead  die  grower 
to  attend  to  it  more  minulei)  than  he  has 
done.  All  artificial  tinges  which  he  gtyei 
to  the  fleece,  b\  means  of  ruddle  or  ochre, 
or  any  substance  of  that  description,  in 
order  to  increase  the  beauty  of  the  flock, 
injures  the  pile  as  much  as  the  rouge 
used  by  our  ladies  of  fashion,  to  heighten 
their  native  charms,  does  the  skin  to 
which  it  is  applied.  When  this  painted 
wool  is  submitted  to  the  dyer's  hands, 
unless  washed  at  some  little  expense  of 
time  and  labour,  the  foreign  substances 
mingle  with  the  colouring  ingl  edtcnts  and 
spoil  their  effect  But  indeed  what  can 
we  expect  but  dull  and  heavy  tints,  faint, 
muddy  and  uncertain  colours,  where  wool 
is  dyed,  as  is  too  much  the  custom  in 
Yorkshire,  without  being  scoured,  in  pans 
unwashed,  and  with  materials  mixed  to- 
gether upon  a  floor  unswept,  where  a  lit- 
tle before,  perhaps,  have  been  mingled 
ingredients  calculated  to  produce  a  total- 
ly different  tint.  Such  slovenly  practices 
deserve  reprehension.  The  French  are 
said  10  be  much  cleaner  in  their  manner 
of  dyeing  than  u-e  are,  and  their  colours 
superior  to  our  own. 

Another  object  to  which  the  wool-grow- 
er should  avtend  more  closely  than  he 
has  yet  done,  is  the  Specific  Gravity,  or 
relative  weight  of  the  pile.  It  desirous  to 
ascertain  the  comparative  weight  of  dif- 
ferent samples,  he  must  carefully  bring 
each  of  them  to  the  same  state  of  parity  ; 
must  drive  off  the  moisture  which  wool 
obstinately  retains,  and  extract  from  it  all 
the  air  lodged  in  the  instertices  of  the  sta- 
ple If  this  be  not  exactly  performed,  the 
experiments  he  may  institute  will  be  tri- 
fling  and  delusive.  When  first  attending 
to  this  subject,  in  order  to  render  my 
judgment  of  its  value  more  correct,  I  con- 
ceived that  the  gravity  of  all  wool,  like 
that  of  pure  gold,  was  exactly  alike,  and 
supposed  that  a  correct  knowledge  of  the 
real  weight  of  pure  wool  would  enable 
me  to  ascertain,  with  the  utmost  preci- 
sion, the  quantity  of  other  substances 
mingled  with  it.  But  it  soon  appeared 
that  wool  in  the  purest  state  to  which  I 
could  attain,  did  not  possess  exactlv  the 
same  relative  weight;  that  when  compa- 
red with  water,  it  varied  from  seventv- 
five  to  a  hundred,  i.  e.  some  samples  were 
really  lighter  than  others  in  the  propor- 
tion of  five  to  three.  The  experiments 
Were  deemed  correct  enough  for  the  com- 
mon purposes  of  trade,  but  are  not  con- 
sidered  sufficiently  accurate  for  the  nicer 
*  H 


woo 


woo 


calculations  of  the  philosopher.    Nor  was 

I  able  to  ascertain,  whether  the  difference 
observed  was  merely  accidental  in  the  par- 
ticular wools  under  inspection,  or  follow- 
ed some  general  law  connected  with  the 
bl  eed,  or  the  cirumstances  in  which  the 
p.ie  was  produced  The  mere  coarseness 
or  fineness  of  the  staple  does  not  effect 
the  specific  gravity  of  it,  nor  does  the 
fine,  close,  and  well-grown,  wool  of  the 
shoulder  differ  very  materially  in  this  res- 
pect, from  the  thii)  and  hairy  breech.  The 
clothier  commonly  examines  this  proper- 
ty of  wooi,  without  being  conscious  of 
the  principles  upon  which  he  depends ; 
he  is  well  aware  that  a  given  weight  of 
some  kinds  of  wool  will  produce  more 
cloth  tnan  the  same  quantity  of  a  sort 
equally  fine,  shorn  from  a  different  pas- 
tu/e;  but  he  usually  attributes  the  differ- 
ences or  the  bulk,  which  he  perceives  in 
sheets  of  wool,  to  the  purity  of  one  sam- 
ple, and  to  the  extraordinary  quantity  of 
dirt  mingled  with  the  other."  Such  a  de- 
cision is  generally  very  correct ;  but  when 
he  measures  the  size  of  a  sheet  with  his 
eye,  and  tries  the  tenseness  of  ft  with  his 
fingers,  he  houid  recollect  that  there  is  a 
difference  in  tue  elasticity  of  wool,  in  the 
manner  m  which  the  pile  is  disposed,  m 
the  mode  of  packing  it,  and  in  the  specific 
gra«n\  which  m.i>  cause  as  great  a  vari- 
ation in  me  appearance  of  a  package,  as 
that  arising  from  the  purity  or  dirtiness 
of  the  staple.  The  importance  of  ren- 
dering woui  as  light  as  possible,  is  clear 
to  every  one  who  considers  that  the  quan- 
tity of  cloth,  which  a  given  weight  will 
produce,  is  the  true  test  of  its  value.  Yet 
the  grower,  as  though  totally  negligent  of 
so  plain  a  principle,  has  often  been  soli- 
citous to  increase  the  weight  of  his  fleece, 
without  considering  whether  he  augment- 
ed the  quantity  or  the  density  of  the  pile  ; 
a  distinction  with  which  every  other  clo- 
thier must  be  acquainted,  although  he  may 
express  his  ideas  in  different  language, 
for  he  buys  the  material  by  weight,  and 
sells  it  when  manufactured  by  measure. 
In  this  case  there  can  be  no  doubt  res- 
pecting the  person  from  whom  we  must 
expect  improvement  The  manufacturer 
cannot  change  ihe  nature  of  the  materials  ; 
he  must  work  such  as  he  finds,  and  from 
among  imperfect  ones,  selects  the  best. — 
But  since  tile  art  of  combining  the  pro. 
perties  of  the  parent  sheep,  in  their  off- 
spring, is  generally  known,  the  grower  of 
Wool  has  it  in  Ins  power  to  produce  sur- 
prising alterations;  Nature  has  appoint- 
ed agriculturists  the  chief  dispensers  of 
her  favours,  and  society  justly  expects 
much  from  their  attention. 

The  smell  of  wool,  though  very  ofen 
applied  to,  as  a  test  yf.its  condition,  is  one 


of  the  least  important  circumstances  con- 
nected with  it.  Provided  it  produce  no 
disagreeable  sensation  upon  the  olfactory 
nerves,  and  betray  none  of  the  effects  of 
moisture,  there  is  no  one  particlar  scent 
which  we  deem  preferable  to  another. — 
Pure  and  perfect  wool,  1  suspect  has  no 
smell ;  yet  it  is  a  very  singular  fact,  that 
fleeces  produced  in  different  countries, 
and  even  in  the  various  provinces  of  the 
same  kingdom,  convey  by  their  peculiar 
odour  a  strong  attestation  of  the  district 
were  they  grew.  The  fact  depends  chief- 
ly, 1  suppose,  upon  the  constitution  of 
the  animals  ;  because  the  fleece  of  a  1  am 
is  distinguished  from  that  of  any  other 
sheep,  and  quadrupeds  of  different  tribes 
are  well  known  to  produce  very  dissimi- 
lar sensations  on  l he  sense  of  smelling. 
It  would  be  curious,  perhaps  more  than 
curious,  to  ascertain  the  cause  of  this 
'  fact  more  accurately,  especially  as  our 
researches  into  nature  are  generally  re- 
,  paid  by  the  acquisition  of  useful  know- 
ledge. 

But  a  far  more  valuable  quality  remains 
to  be  noticed,  one  which  the  wool  grower 
snould  observe  with  the  closest  attention. 
In  technical  language,  it  is  called  the  true- 
ness  of  the  hair;  and  I  know  of  no  other 
phrase,  which  so  completely  conveys  the 
idea.    When  speaking  upon  the  quality 

•  of  fleeces  as  they  exist  in  a  neglected 
state,  it  was  observed  that  they  are  com- 
posed of  coarse  shaggy  hair,  and  a  more 

'  .^oft  and  downy  pile-  The  natural  effect 
of  culture,  is  the  banishment  of  the 
coarse  and  brittle  filaments  from  the  sta- 
ple, and  the  increase  of  that  substance, 
which  is  more  soft  and  pliable.  But  with- 

'  out  minute  attention,  it  requires  a  long 
coarse  of  years  to  render  the  pile  perfect; 
and  the  cultivators  of"  the  fleece  relax 
their  attention  most  commonly  before 
they  have  rendered  the  piie  uniform. — 
Most  of  the  fleeces  of  Scotland  are  still 
defective;  many  of  the  finer  sorts  pro- 
duced upon  the  English  plains,  and  even 

|  those  of  Italy  and  Spain,  notwithstanding 
their  boasted  superiority,  cannot  claim 
an  absolute  freedom  from  a  hair,  which 
debases  the  staple.  Sometimes  these  in- 
ferior filaments  are  thinly  scattered 
through  the  pile,  and  rising  above  its  ge- 
ne al  surface,  give  it  a  loose  appearance, 
which  authorizes  the  common  represen- 
tation of  it  as  a  bearded  fleece. 

Under  the  general  description  of  wool 
not  true-haired,  we  also  include  that  in 
which  the  points  of  the  staple  are  coarser 
than  the  part  of  it,  which  rose  from  a  less 
distance  from  the  pelt ;  and  also  that 
where  any  portion  of  the  filament  is  per- 
ceptibly thinner  than  another,  to  the  uiv 

;  assisted  eve.    When  examined  with  a 


woo 


woo 


microscope,  we  seldom  find  wool  equally 
fii  e,  through  the  whole  length  of  the  pile 
Frequently  it  becomes  suddenly  thinner, 
as  though  the  pore  through  which  a  fila- 
ment passed,  had  been  contracted  and 
gradually  expanded  itself,  again  toitsna 
tural  dimensions,  permitting  the  hair  to 
been  me  in  the  same  proportion,  more 
thick  and  even.  Sometimes  a  hair  when 
seen  in  profile,  has  one  of  its  outlines 
Straight  and  even,  while  the  other  is  very 
irregularly  indented,  as  though  its  pore 
had  suffered  a  contraction  only  on  one 
side.  Each  of  these  minute  variations, 
confirms  the  opinion  of  Dr  Anderson,vvho 
supposes  that  the  port  s  of  the  skin,  ex- 
pand and  contract,  as  the  temperature,  to 
which  the  sheep  is  exposed,  rises  to  a 
higher  degree  of  warmth,  or  becomes 
mot  e  cool.  Yet  as  these  irregularities  do 
not  materally  affect  the  value  of  manufac- 
tured articles,  unless  easily  distinguished, 
it  seemed  right  to  bound  the  description 
of  ;i  had  quality,  by  a  restrictive  phrase. 
When  these  sudden  contractions  in  the 
size  of  the  pile,  occur  in  long  wool,  the 
effects  are  more  pernicious  than  in  the 
shorter  piles,  for  they  often  render  the 
staple  too  weak  to  endure  the  violence  of 
the  comb  ;  and  totally  unfit  it,  for  its  na- 
tural and  appropriate  manufacture.  This 
thinner  part  of  the  filament,  which  the 
manufacturers  denominate  a  joint,  is  more 
frequently  observed  in  hog  fleeces,  than 
any  other  ;  and  is  commonly  found  near 
the  bottom  of  the  staple,  evidently  the 
effect  of  a  cause,  which  operated  while 
that  part  of  the  pile  was  passing  through 
the  pelt,  and  which  continued  to  affect  it 
only  for  a  short  period  ;  for  the  parts  of 
the  staple  immediately  above  and  below 
the  joint,  appear  in  their  natural  state  — 
The  precise  period  when  the  effect  was 
produced,  may  be  ascertained  by  ob- 
serving the  length  of  wool,  which  has 
grown  since  :  and  perhaps  this  circum- 
stance may  lead  to  the  true  cause  of  it, 
which  I  believe  will  generally  be  found, 
to  be  either  cold,  hunger  or  ill-health.— 
This  joint  is  more  observable  in  long  wool 
than  short,  doubtless  because  the  former 
grows  much  more  rapidly  than  the  latter, 
for  a  sheep  of  the  heavier  breeds,  produ- 
ces a  staple  of  fifteen  inches  long,  in  the 
same  time,  that  one  of  a  different  kind 
perhaps,  will  not  extend  to  more  than 
three  ;  and  the  animal  yielding  long  wool 
is  commonly  more  tender  than  the  oilier, 
less  able  to  endure  the  bitterness  of  the 
blast,  and  the  gnawing  pains  of  hunger. 
Perhaps  the  difference  between  one  part 
of  a  filament  and  another,  may  be  more 
considerable  than  wool-growers  are  aware 
of.    I  have  met  with  some  hairs,  selected 


from  the  worst  part  of  a  fleece,  where 

the  difference  beiween  the  diameter  of 
the  point,  and  that  of  the  other  end  was 
at  least  as  five  to  one  ;  so  that  a  given 
length  of  pile,  when  selected  from  one 
part  of  the  staple,  weighs  twenty  five 
limes  as  much,  as  the  same  length  sepa- 
rated from  the  other  part.  This  extreme 
case  is  mentioned  in  order  to  convince 
the  grower,  that  the  trueness  of  the  hair, 
is  a  quality  of  no  trifling  consideration, 
and  impossible  to  excite  his  attention  to  it, 
for  there'  are  very  few  British  fleeces,  in 
which  the  points  of  the  staple,  are  not 
visibly  coarser  wool  than  their  bases  — 
'Tis  with  pleasure  we  acknowledge,  that 
much  has  been  done  to  remedy  this  de- 
fect, although  constrained  to  add,  much 
remains  to  be  effected 

The  short  account  already  given  of  the 
operations  of  carding,  combing  and  spin- 
ning, is  sufficient  to  show  how  very  im- 
portant it  is,  that  the  manufacturer  should 
be  able  to  select  wool  of  a  perfect  pile, 
more  especially  that  it  should  possess  no 
inequalities  of  the  filaments  ;  that  they 
should  be  equally  elastic,  and  strong 
through  their  whole  length ;  for  wool  des- 
titute of  uniformity  in  any  of  tin.  se  parti- 
culars, will  place  its  coarser  portion  upon 
the  surface  of  the  cioth.  This  fact  is  re- 
peated, as  one  which  ought  to  be  imprint- 
ed upon  the  memory,  both  of  the  stapler 
and  the  shepherd. 

Another  kind  of  hair  is  sometimes  found 
in  the  staple,  which  is  more  pernicious  10 
cloth,  and  most  other  articles,  than  the 
filaments  already  described.  It  is  gene- 
rally short,  pointed,  brittle  and  opaque, 
exactly  like  that  produced  upon  the  faces 
and  shanks,  of  most  English  sheep.  Its 
colour  is  commonly  whiteoometimes  gray 
or  brown  ;  and  among  British  manufac- 
turers, it  is  called  a  kevnp  or  stichel  hair, 
and  not  unfrequently  from  its  resem- 
blance, to  that  of  the  feline  species,  cat's 
hair.  Kemps  are  commonly  much  coarser 
than  the  wool,  in  which  they  are  found, 
and  often  so  intermingled  with  it,  as  not 
to  be  separated,  even  by  the  motion  of 
the  scribbling  machine.  They  will  receive 
no  artificial  tints,  but  from  the  most  cor- 
rosive ingredients;  and  by  their  hardness, 
the  sharpness  of  their  points  and  their 
coarseness,  spoil  the  article  in  which  ilvy 
are  mingled.  The  fleeces  most  common- 
ly infested  with  them,  are  those  produced 
by  neglected  breeds  of  sheep,  or  animals 
grown  old,  and  are  common  both  to  Bri- 
tish and  foreign  families.  In  long  fleeces 
they  are  not  very  frequently  observed, 
but  when  met  qfcfh,  are  collected  in  the 
noil,  and  render  it  much  less  valua- 
ble. 


XAN 


XAN 


These  are  the  most  general  qualities 
of  the  fleece,  10  which  the  manufacturer 
attends,  and  we  hope,  that  they  are  de- 
scribed in  such  a  manner,  as  will  enable 
t  e  wool-grower,  to  form  some  distinct 
notions  upon  points,  which  he  should  keep 
constantly  in  view.  He  has  often  com- 
pound, that  the  stapler  appeared  to  him, 
capriciously  to  prefer  one  fleece  to  ano- 
ther, and  has  been  confounded  to  observe, 
that  improvements  suggested  and  warm- 
ly recommended  by  one  buyer,  have  been 
totally  disregarded  or  condemned,  as  per- 
nicious to  another  But  had  the  farmer 
recollected,  that  wool  is  used  lor  very  va- 
rious purposes,  which  require  a  corres- 
ponding difference  in  the  materials  ;  that 
the  manufacturer  of  one  article,  seldom 
understands  the  mode  of  producing  ano- 
ther ;  and  that  most  staplers  content  them- 
selves with  purchasing  only  one  kind  ot 
wool ;  he  would  rather  have  expected  a 
difference  of  opinion,  than  have  been  sur- 
prized when  he  found  one.  It  is  singular 
that  a  trade  so  very  simple,  as  that  ap- 
pears to  be,  which  consists  in  purchasing 
a  quantity  of  rleeces,  breaking  them  into 
a  number  of  arbitrary  divisions,  and  sell- 
ing the  sorts  in  their  raw  state,  should  be 
so  much  divided  :  one  of  the  best  proofs 
that  the  art,  simple  as  it  appears,  hasat- 
tained  a  high  degree  of  perfection  Per- 
sons who  purchase  their  wool  in  the 
South  of  England,  for  instance,  seldom 
either  buy,  or  understand  the  value  of 
fleeces,  produced  in  the  north.  Some  lay 
out  their  capital  chiefly  in  the  East,  others 
almost  entirely  in  the  West,  and  some 
take  only  a  middle  course,    ft  umbers  do 


business  in  long  wool,  a  great  many  con- 
fine themselves  entirely  to  the  shorter 
pile,  while  a  few  understand  only  the  low- 
er sorts  ;  or  trade  in  the  finer,  or  in  fo- 
reign wools  alone.  We  speak  not  here 
of  persons  confined  by  local  situation,  to 
only  one  kind  of  fleeces  but  of  those  who 
reside  in  the  very  market  where  every 
kind  is  consumed,  and  btfore  whom  the 
kingdom  and  the  worid  is  open  ;  of  per- 
sons through  whose  hands,  by  far  the 
greater  part  of  fleeces  produced  in  the 
island  must  pass,  and  who  perhaps  are 
the  most  favourably  situated,  for  attain- 
ing correct  information,  respecting  the 
qualities  of  the  fleece,  and  state  of  the 
manufacture  They  expect  much  from 
tne  growers  of  the  pile,  but  are  disposed 
to  exercise  candour  towards  them,  recol- 
lec  ing  that  there  are  circumstances  in 
everS  farm,  to  which  the  grazier  must 
attend,  whose  nature  he  cannot  change, 
and  whose  effect  notwithstanding  all  he 
i  an  do,  will  still  be  visible.  It  is  desira- 
ble to  ascertain,  how  far  their  pernicious 
influence  is  unavoidable, and  what  are  the 
means  of  counteracting  it.  TVe  wool- 
grower's  own  interest,  the  main  spring  of 
almost  every  commercial  and  agricultu- 
ral transaction,  prompts  to  the  investiga- 
tion and  to  the  use  of  remedies.  See  Ani- 
mals Domestic  See  also  Manufac- 
ture of  Cloth,  &c. 

WORM  WOOD,  Salt  of'.  See  Carbo- 
nate of  Potash. 

WORM  TUBE.  See  Distillation. 

WORT.    See  Brewing. 

WOUNDS  mFarritry,  See  Farriery. 

WRITING  INK.    See  Ink. 


X 


XANTHORHIZA,  tinctoriz,  Slirub  Yel- 
low Root.  Is  a  native  plant  of  N.  Caro- 
lina. 

Dr.  Woodhouse  in  the  5th  vol.  of  the 
Medical  Repository  of  New-York,  ob- 
serves, that  the  Xanthorhiza  tinctoria, 
contains  a  gum  and  resin,  both  of  which 
are  intensely  bitter ;  the  resin  is  more 
abundant  than  the  gum. 

It  imparts  a  drab  colour  to  cloth,  and 
a  handsome  yellow  to  silk,  but  the  dye 
will  not  take,  on  cotton  or  linen.  The  dif- 
ferent mordants  w  hich  were  used,  altered 
the  shade  of  the  yellow  colour  consider- 
ably, but  did  not  appear  to  render  it  more 
permanent  While  every  shade  of  this 
elegant  colour  can  be  obtained,  from  that 
truly  valuable  dyeing  drug,  the  quercitron 
hark,  (black  oak,)  Dr.  Woodhouse  thinks 


it  will  always  supersede  the  xanthorhiza, 
and  every  other  native  dye,  among  which 
that  of  the  Hydrastis  Canadensis,  may  just- 
ly be  reckoned  the  most  superb. 

Dr.  Mease,  remarks,  that  the  watery 
extract  of  the  grated  roots,  mixed  with 
aium,  and  added  to  Prussian  blue,  was 
first  used  by  Mr.  James  Bartram,  for  co- 
lon: ing  plants,  and  the  plumage  of  birds 
of  a  green  colour.  The  green  is  far  more 
lively  and  elegant,  than  that  made  of  gam- 
boge and  Prussian  blue,  which  is  gene- 
rally used  for  painting  in  water  colours, 
and  stands  well  in  the  shade,  but  soon 
contracts  a  dull  colour,  when  exposed  to 
a  bright  light,  and  to  a  high  temperature. 
Various  subjects  coloured  by  this  green, 
and  mclosed  in  a  book,  were  as  lively  af- 
ter one  year,  as  when  first  painted* 


YAR 


YEA 


YARN.  The  conversion  of  flax,  hemp, 
cotton,  wool,  &c.  into  filaments  or  threads, 
is  denominated  yarn. 

Originally  the  distaff  was  the  means 
employed,  to  perform  the  operation,  with- 
out any  otiier  means,  but  at  present  the 
operation  of  spinning  is  performed  in  the 
large  way,  by  the  help  of  machinery  See 
Spinning  and  Manufacture  of 
Cot  i  on  ;  in  which  the  machinery  ;s  de- 
scribed. In  addition,  however,  it  may  be 
proper  to  notice  in  this  place,  the  machine 
invented  by  Messrs.  Kendrow  and  Port- 
house,  though  it  has  been  superseded  by 
more  modern  inventions.  For  a  more  mi- 
nute description  than  what  is  here  given, 
we  refer  the  reader  to  the  16th  vol.  of  the 
Repertory  of  Arts. 

The  machine  consists  of  a  frame,  which 
supports  a  cylinder,  three  feet  in  diame- 
ter, and  ten  inches  in  bread  h  ;  made  of 
dry  wood  or  metal ;  and  its  circumference 
being  covered  with  smooth  leather  On 
this,  are  placed  six  rollers,  also  covered 
with  leather,  and  upheld  in  their  situa- 
tions, by  slits  made  in  a  piece  of  wood,  in 
which  the  iron  axis  of  the  rollers  move, 
at  the  same  time  suffering  them  to  press 
on  the  principal  wheel :  such  rollers  are 
of  different  weights ;  the  highest  on  the 
cylinder  weighing  two  stone,  while  the 
others  gradually  decrease,  so  that  the  low- 
est is  only  two  pounds  in  weight.  A  cloth 
is  placed  beneath  the  cylinder,  that  re- 
volves upon  two  rollers,  inserted  in  the 
frame  ;  and  by  its  side  there  is  a  table  of 
an  equal  length  and  breadth,  furnished 
with  two  similar  cloths. 

The  workman  lays  on  this  table  a  great- 
er or  smaller  quantity  of  the  material  in- 
tended to  be  spun,  according  to  the  de- 
gree of  fineness  required ;  spreading  it 
uniformly  on  the  cloths,  whence  he  re- 
moves and  applies  it  to  the  revolving 
cloth.  The  rollers  and  cylinders  are  then 
put  in  motion  by  wheel-work,  moved  by 
a  horse,  water,  or  any  other  impulsive 
power;  the  flax,  Sec  is  drawn  forward, 
and  extended,  during  its  passage,  into  a 
thread  or  sliver;  which,  on  being  sub- 
mitted to  the  action  of  a  similar  machine, 
but  of  different  dimensions,  is  spun  into 
thread  of  various  degrees  of  fineness  :  af- 
ter the  yarn  has  thus  passed  beneath  the 
rollers,  it  falls  into  canisters  below,  for 
its  reception. 

YARN,  Dyeing  of.    See  Dyeing. 
YARN,  Bleaching  of    See  Bleach- 
ing. 


YARN,  Weaving  of.    Sec  Weaving. 

YEAST,  or  Harm,  is  the  froth  which 
rises  on  beei,  during  us  fermentation. 

The  uses  of  yeasi  are  numerous,  and 
the  source  from  which  it  is  generally  ob- 
tained, is  not  sufficient  to  supplv  the  de- 
mand. Unless  properly  preserved,  when 
kept  in  large  quantities  it  is  apt  to  spoil. 
We  propose  therefore  to  shew  how  it  may 
be  made  from  several  materials,  and  how 
to  preserve  it,  when  mude,  be  the  modes 
of  obtaining  it  what  they  may.  For  this 
purpose,  we  have  availed  ourselves,  as 
heretofore,  of  the  observations  of  differ- 
ent gentlemen. 

In  the  2d  vol.  of  the  "  Memoirs  of  the 
Philosophical  and  Literary  Society  of 
Manchester,"  Mr  Henry  has  pubhsned  a 
method  of  preparing  artificial  yeast,  by 
which  good  bread  ma\  be  made,  without 
the  aid  of  any  other  ferment  He  directs 
flour  and  water  to  be  boiled  to  the  con- 
sistence of  treacle  ;  and  w  hen  the  mixture 
is  cold,  to  saturate  it  with  fixed  air.  Next, 
it  must  be  poured  into  large  bottles  wiih 
narrow  mouths,  which  shouid  be  loosely 
covered  with  paper  ;  and,  over  this,  with 
a  slate  and  a  weight,  to  keep  them  steady. 
The  bottles  ought  now  to  be  placed  in  a 
room,  the  temperature  of  which  is  from 
70  to  bOu  Fahr.  and  the  mixture  be  stir- 
red two  or  three  times  in  the  course  of 
24  hours.  At  the  end  of  about  two  days, 
according  to  Mr.  Henry,  such  a  degree 
of  fermentation  will  have  ensued,  that  the 
mixture  acquires  the  consistence  of  yeast. 
In  this  state,  the  flour,  intended  to  be 
made  into  bread,  must  be  incorporated 
with  such  artificial  barm,  in  the  propor- 
tion of  six  pounds  of  the  former  to  one 
quart  of  the  latter,  and  a  due  quantity  of 
warm  water  The  whole  is  now  to  be 
kneaded  together  in  a  proper  vessel,  co- 
vered with  cloth,  and  suffered  to  stand 
for  12  hours,  or  till  it  be  sufficiently  fer- 
mented ;  when  it  should  be  formed  into 
loaves,  and  baked.  Mr  Henry  adds,  that 
this  yeast  would  be  more  perfect,  if  a  de- 
coction of  malt  were  substituted  for  wa- 
ter. 

A  simple  decoction  of  malt,  however, 
is  now  fully  proved  to  be  convertible  into 
yeast,  fit  for  brewing  :  this  discovery  was 
made  by  Mr.  Joseph  Senyor,  on  whom 
the  Society  for  the  Encouragement  of 
Arts,  in  the  year  1790,  conferred  a  boun- 
ty of  2U».  He  directs  three  wooden  or 
earthen  vessels  to  be  procured,  one  being 
capable  of  holding  two  quarts,  the  other 


YEA. 


YE  A. 


three  or  four,  and  the  third  five  or  six  |  putrefaction.  It  was  equally  divided,  one- 


quarts.  A  quarter  of  a  peck  of  malt  is 
then  to  be  boiled  for  eight  or  ten  minutes, 
in  three  pints  of  water ;  when  one  quart 
must  be  poured  off  the  grains,  into  the 
first  vessel :  as  soon  as  the  liquor  becomes 
cool,  such  vessel  ought  to  be  removed 
towards  the  fire,  or  to  a  temperature  of 
about  70  or  80°  of  Fahrenheit's  thermo- 
meter.   In  the  course  of  30  hours,  the 


half  impregnated  with  fixed  air,  as  in  the 
first  experiment ;  each  was  put  in  a  wood- 
en vessel,  and  both  were  placed,  in  an 
equally  warm  situation.  U  the  expira- 
tion of  24  hours,  there  being  no  signs  of 
fermentation,  1  stirred  in  a  tea-spoonful 
of  salt,  and  shook  a  littie  flour  on  the  sur- 
face of  each.  In  12  hours  more,  the  un- 
impregnated  wort,  shewed  some  appear- 


fermentation  will  commence;  when  two  ance  of  fermentation,  which  went  oft",  and 


quarts  of  a  similar  cool  decoction  (made, 
we  suppose,  from  the  same  malt,)  must 
be  mixed  with  this  yeast  in  the  second 
or  larger  vessel ;  and  be  repeatedly  stir- 
red in  the  manner  practised  in  common 
vats.  As  the  fermentation  increases,  a 
greater  portion  of  the  like  decoction  must 
be  added,  and  be  worked  in  the  largest 
vessel :  thus,  at  length,  a  sufficient  quan- 
tity of  yeast  will  be  produced,  for  brew- 
ing 40  gallons  of  beer. 

This  useful  contrivance  of  Mr.  Senyor, 
is  farther  confirmed  by  the  recent  expe- 
riments of  a  correspondent,  whose  plain 
and  interesting  account  we  are  induced 
to  quote  in  his  own  words  :  "  I  caused 
*  (says  he)  a  gallon  of  rat  her  weak  wort  to 
be  made  ;  with  part  of  which,  when  cool, 
I  filled  the  middle  part  of  Nooth's  ma- 
chine :  as  soon  as  it  was  thoroughly  sa- 
turated with  fixed  air,  1  mixed  the  whole, 
and  placed  it  in  a  wooden  vessel  near  the 
fire,  tfie  weather  being  rather  cool.  In 
about  24  hours,  there  were  some  faint 
signs  of  fermentation  ;  yet,  ai  the  expira- 
tion of  the  fourth  day,  I  obtained  no  more 
than  two  table-spoonfuls  of  very  indiffer- 
ent yeast ;  and  the  wort  had  become  ex- 
tremely offensive.  As  the  yeast  was  not 
only  very  poor,  but  in  too  small  a  quanti- 
ty for  any  domestic  purpose,  I  made  an 
infusion  of  malt,  and  a  decoction  of  hops, 
in  the  manner  used  among  the  inhabitants 
of  the  island  of*  Jersey,  when  they  find  it 
necessary  to  increase  a  small  quantity  of 
brewer's  yeast.  To  this  preparation,  I 
added  my  two  spoonfuls  of  yeast  ;  let 
the  mixture  stand  24  hours,  then  poured 
off  the  watery  part ;  mixed  the  sediment 
with  an  increased  proportion  of  the  malt 
and  hops;  which  fermented,  and  produc- 
ed yeast  enough  to  worka  gallon  of  strong 
beer,  that  yielded  a  pint  of  very  fine  yeast, 
of  which  excellent  bread  was  made  Hav- 
ing some  reason  to  suspect,  that  the  fixed 
air,  was  of  little  or  no  use  in  this  experi- 
Bent,  and  that  a  wort  might  be  made,  !  f< 


was  renewed  by  placing  tiie  liquor  near 
the  fire  ;  and  at  the  74th  hour,  it  had  a 
tolerably  good  head  of  yeast ;  but  the  im- 
pregnated wort,  was  only  beginning  to 
ferment,  In  24  hours  after,  we  took  a 
pint  of  yeast  from  the  wort,  which  was 
not  impregnated  with  fixed  air,  and  about 
a  tea-cupful  from  the  other,  which  was 
as  inferior  in  quality,  as  in  quantity.  The 
worts  were  then  mixed,  put  into  other 
vessels,  and  hid  fair  to  become  excellent 
beer.  1  cannot  say  that  this  is  a  very  ex- 
peditious mode  of  making  yeast;  but  I  be- 
lieve it  is  a  sure  one,  and  within  the  pow- 
er of  every  person,  who  can  procure  the 
necessary  ingredients  for  making  good 
beer."  .  Our  correspondent,  therefore, 
conceives  to  have  proved  by  his  experi- 
ment, "  that  fixed  air  is,  at  least,  not 
requisite  to  produce  a  fermentation  in 
beer." 

Dr.  Lcttsom  ("Hints  for  promoting  Be- 
neficence," &c-  1797,)  recommends  the 
following  preparation  as  a  substitue  for 
yeast :  B^il  four  ounces  of  flour  in  two 
quarts  of  water,  for  half  an  hour;  and 
sweeten  it  with  three  ounces  of  Muscova- 
do sugar.  When  the  mixture  is  nearly 
cold,  pour  it  on  lour  spoonfuls  of  yeast, 
into  an  earthen  or  stone  jar,  sufficiently 
deep  to  admit  the  new  barm  to  rise  :  it 
must  now  be  well  shaken,  placed  near 
the  fire,  for  one  day,  and  then  the  thin 
liquor  poured  off  the  surface.  The  re- 
mainder is  next  to  be  agitated,  strained, 
closed  up  for  use, and  kept  in  a  Coo'  place. 
Some  of  the  yeast  thus  prepared,  ought 
always  to  be  preserved,  for  renewing  or 
making  the  next  quantity  that  may  be 
wanted. 

The  following  method  of  preparing  ex- 
cellent yeast,  we  state  from  the  "  Tran- 
sactions of  the  Economical  Society  of  Pe- 
tersburg!}," oii  the  authority  of  Baton 
Von  Mestmacher:  when  the  wort  is  made, 
and  it  becomes  necessary  to  provide  yeast 
its  fermentation,  he  directs  40  gallons 


which  would  ferment  of  itself,  before  the  to  be  drawn  off,  into  a  vessel  provided 
liquor  was  spoiled  by  too  long  keeping,  |  with  a  lid,  and  capable  of  holding  one- 
I  caused  to  be  made  four  gallons  of  good  j  third  more  than  that  quantity.  Next,  se- 
wort,  rather  above  porter  strength,  well  ven  pounds  of  leaven  are  to  be  dissolved 
bopped,  and  with  a  considerable  quantity  in  a  little  wort,  and  mixed  with  the  forty 
of  colour,  and  treacle,  to  preserve  it  from  I  gallons:  17  pounds  of  rye-meal,  and  an 


YEA 


YEA 


equal  quantity  of  ground  malt,  must  now 

be  lidded,  by  agitation  for  some  minutes, 
and  suffered  to  stand  for  half  an  hour. 
Ai  ttie  end  of  that  time,  a  spoonful  of  the 
best  yeast  ought  to  be  incorporated  with 
this  compound;  I  he  lid  is  to  be  placed  upon 
the  vessel,  and  the  whole  to  remain  undis- 
turbed for  48  hours;  when  the  mixture 
will  be  found  converted  into  60  gallons  of 
remaikabh  good  barm. 

In  the  1st  vol  ot  "  Annals  of  Agricul- 
ture," Mr.  Kirby  suggests  mealy  pota- 
toes to  be  boiled,  till  tlicy  become  per- 
fectly soft,  in  which  htate,  they  must  be 
mashed  with  hot  water,  so  as  to  acquire 
the  consistence  of  yeast.  Two  ounces  of 
coarse  sugar,  or  molasses,  are  then  to  be 
added  to  every  pound  of  potatoes  ;  and, 
when  the  mixture  is  lukewarm,  two  spoon- 
fuls of  barm  must  be  stirred  into  it,  ac- 
cording to  the  proportion  above  stated. 
This  composition  should  not  be  removed 
tow  ards  the  fire,  or  to  a  warm  place,  till 
the  fermentation  cease  ;  when  a  certain 
portion  may  be  kneaded  with  flour,  which 
ought  to  stand  eight  hours  before  it  is 
baked.  Mr.  Kirby  observes,  that  every 
pound  of  potatoes,  thus  managed,  produ- 
ces nearly  a  quart  of  yeast,  which  will  re- 
main good  for  three  months.  The  roots, 
however,  ought,  in  the  opinion  of  Mr. 
Borderly,  to  be  perfectly  ripe  and  well- 
sprouted  ;  as  in  the  contrary  case,  no  fer- 
mentation will  ensue. 

Similar  to  this  preparation,  is  the  sub- 
stitute for  yeast,  contrived  by  Mr.  Richard 
Tillyer  Biunt;  in  consequence  of  which 
he  obtained  a  patent,  in  October,  1737  — 
He  directs  eight  pounds  of  potatoes  to  be 
boiled  in  water,  in  the  same  manner  as 
for  the  table  :  after  which,  they  must  be 
mashed  ;  and,  while  they  are  warm,  two 
ounces  of  honey,  or  other  saccharine  mat- 
ter, and  one  quart  of  common  yeast  should 
be  added.  Three  pints  of  this  compound 
are  sufficient,  with  the  aid  of  warm  wa- 
ter, for  making  the  sponge ;  and,  when 
this  begins  to  sink,  the  dough  ought  to 
be  formed  into  loaves,  and  baked. 

The  mode  of  separating  beer  from  yeast 
and  preserving  the  yeast  for  a  great 
length  of  time,  and  in  any  climate,  is  thus 
given  by  Mr-  Matthew,  who  obtained  a 
patent  for  the  above  mentioned  object, 
which  may  be  found  in  the  Repertory  of 
of  Arts,  vol.  v.  p.  73.  Mr.  M.  uses  a 
press,  with  a  lever,  the  bottom  made  of 
stout  deal,  oak,  or  any  other  timber  fit 
for  the  purpose,  raised  with  strong  feet  a 
convenient  height  from  the  ground,  so  as 
to  admit  the  beer  to  run  off  into  whatever 
is  prepared  to  receive  it.  lrto  the  back 
of  it,  is  let  a  strong  piece  of  timber,  or 
any  other  fit  material  to  secure  one  end 


of  the  lever,  the  top  of  which  is  secured 
by  being  well  wedged  up  to  a  girder,  or 
the  joists  at  the  top  of  the  building.  Ira 
this  piece  of  timber  is  mortised  one  end 
of  the  lever,  which  is  fastened  into  the 
mortise  with  an  iron  pin,  or  otherwise 
properly  secured;  the  whole  well  secu- 
red with  iron  work  I  he  yeast  is  then  put 
into  bags  rm.de  ot  sail  cloth,  or  any  other 
strong  cloth  or  material,  and  carefully 
tied  or  secured,  then  placed  flat  on  the 
press ;  a  boar  d  is  then  laid  on  it,  and  the 
lever  let  down  on  it,  and  weights  are 
hung  at  the  other  end  of  the  lever  by 
hooks  or  otherwise,  and  weights  are  add- 
ed as  the  beer  runs  from  the  bag,  care 
being  taken  not  to  burst  the  bag,  nor 
force  the  beer  out  too  thick ;  to  prevent 
which,  the  bag  is  placed  in  a  trough  of 
a  proper  size,  with  a  false  bottom,  bored 
full  of  holes,  (the  sides  and  ends  being; 
likewise  bored  mil  of  holes)  and  blocks 
put  above  for  the  lever  to  act  upon.  When 
a  sufficient  weight  has  been  added  so  as 
completely  to  force  the  beer  out,  which 
may  be  done  by  a  screw  press*  if  necessa- 
ry, the  yeast,  which  remains  in  the  bag, 
will  crumbie  to  pieces  hke  Hour.  It  must 
then  be  thinly  spread  upon  frames  made 
with  thin  canvas,  hair  cloth,  or  any 
other  thing,  which  will  permit  the  heat  to 
pass  freely  through  it,  in  a  room,  kiln  or 
stove,  or  other  place,  where  a  regular 
heat  can  be  kept  up  to  the  temperature 
of  from  about  eighty  to  ninety  degrees  ; 
observing  to  break  it  fine  as  it  dries,  by 
passing  a  board,  or  other  fit  thing  lightly 
over  it.  When  completely  dry,  put  it  in 
tight  casks,  or  bottles,  so  as  to  exclude 
the  air,  or  any  damp  from  it,  and  it 
will  then  keep  a  great  length  of  time,  and 
in  any  climate  When  wanted  for  use,  it 
may  be  dissolved  in  a  small  quantity  of 
wort,  or  sugar  and  water,  of  the  tempe- 
rature of  from  about  eighty  to  ninety  de- 
grees, when  it  possesses  the  same  quality 
as  fresh  liquid  yeast. 

Dr.  Mease  has  given  the  following  inte- 
resting observations  on  this  subject,  which 
contain  a  fund  of  useful  matter: 

The  following  mode  is  most  commonly 
adopted  out  of  the  great  towns  in  the 
United  States  :  Four  table-spoonsful  of 
bran  or  shorts,  and  one  ot*  hops,  are  boil- 
ed in  a  quart  of  water,  and  set  by  the  fire 
to  ferment.  A  small  quantity  of  salt  to 
the  water,  wherewith  the  flour  is  knead- 
ed, is  an  improvement.  With  this,  how- 
ever, the  practice  is  to  use  leaven  saved 
from  a  former  baking. 

Where  bread  is  made  from  leaven 
alone,  some  sugar  should  be  added  to 
correct  the  sour  taste,  and  probably  a 
small  quantity  of  pearl-ash,  would  add  to 


YEA 


YEA 


the  vising"  of  the  bread,  as  well  as  correct 
the  acid  of  the  leaven. 

An  useful  substitute  for  yeast,  may  be 
obtained  by  nearly  filling-  a  bason,  or  tea- 
cup, wiih  bruised,  or  split  pease,  and 
pouring  on  them  boiling  water.  The 
whole  is  now  to  be  set  on  the  hearth,  or 
other  warm  place,  for  24  or  48  hours,  ac- 
cording to  the  temperature  of  the  season. 
At  the  end  of  that  time,  a  froth,  possess- 
ing all  the  properties  of  yeast,  will  appear 
on  the  surface  of  the  fluid.  This  method, 
we  understand,  is  commonly  practised  in 
the  eastern  countries  ;  and  the  barm,  thus 
procured,  is  said  to  l'ender  the  bread 
light  and  palatable. 

To  the  different  modes  of  procuring 
yeast,  alseady  specified,  we  shall  add  an 
easy  and  expeditious  process,  which  ap- 
pears to  be  very  plausible;  and  has  late 
ly  been  communicated  to  the  editor,  by 
an  anonymous  correspondent,  he  cannot 
therefore  vouch  for  its  success.  Take  six 
quarts  of  water,  and  two  handfuls  of 
wheaten,  or  barley  meal,  stir  the  latter  in, 
before  the  mixture  is  placed  over  the 
fire,  where  it  must  very  gradually  sim- 
mer,  and  at  length  boil,  till  two-thirds  of 
the  fluid  be  evaporated,  so  that  it  may 
consist  of  two  quarts.  When  this  decoc- 
tion becomes  cool,  incorporate  with  it  (by 
means  of  a  whisk)  a  powder,  consisting 
of  two  drams  of  salt  of  tartar,  and  one 
dram  of  cream  of  tartar,  previously 
mixed.  The  whole  should  now  be  kept 
in  a  warm  place.  Thus  a  very  strong 
yeast  for  brewing,  distilling,  and  baking, 
is  said  to  be  obtained.  For  the  last  men- 
tioned purpose,  however,  such  barm 
ought  to  be  first  diluted  with  pure  water, 
and  passed  through  a  sieve,  before  it  be 
kneaded  with  the  dough  ;  in  order  to  de- 
prive it  of  the  alkaline  taste. 

The  preservation  of  yeast  for  a  consi- 
derable time,  is  an  object  of  equal  impor- 
tance to  that  of  producing  it  ai  tificially  — 
Hence,  it  has  been  recommended  to  put  a 
quantity  of  that  commodity  into  a  canvas 
bag,  and  to  submit  the  whole  to  the  ac- 
tion of  the  screw  press,  so  as  to  deprive  it 
of  all  moisture;  in  consequence  of  which, 
the  barm  will  remain  in  the  bag,  as  firm 
and  tough  as  clay.  In  this  state,  it  must 
be  packed  in  casks,  well  secured  from 
the  access  of  air,  and  may  ke  kept  in  a 
sound  state  for  any  period  of  time.  We 
believe,  however,  it  would  be  more  safe 
and  advisable  to  form  the  pasty  yeast  into 
circular,  flat  vessels,  resembling  tea-sau- 
cers, and  in  that  sate  to  dry  the  whole 
mass,  either  in  the  open  air  under  shade,  or 
in  the  moderate  warmth  of  a  baker's  oven. 

Another  mode  of  preserving  yeast,  con- 
sists in  throwing  a  witty,  or  the  young- 


shoots  of  willows,  twisted  together,  into 
the  vessel  where  the  yeast  is  working ; 
and  suspending  them  in  a  warm  room,  till 
the  next  opportunity  of  brewing  arrives. 
We  conceive,  however,  the  following  ex- 
pedient to  be  preferable,  both  in  point  of 
cleanliness  and  economy  ;  it  being  suc- 
cessfully practised  by  some  careful  house- 
wives. Take  a  clean  wooden  bowl,  of 
such  size  as  may  be  most  convenient ; 
spread  a  regular  coating  of  yeast  around 
its  inner  surface ;  and,  as  often  as  this 
dries,  tepeat  the  process,  till  a  thick  cake 
be  formed.  -The  vessel  must  be  kept  in 
a  diy„place.  When  any  barm  is  wanted, 
a  small  piece  may  be  cut  out ;  and,  after 
dissolving  it  in  warm  water,  the  solution, 
will  answer  all  the  purposes  of  fresh  yeast, 
whether  designed  for  baking,  or  for  brew- 
ing 

The  following  process  being  advanta- 
geous'y  employed  in  Germany,  for  pre- 
serving barm,  so  as  to  be  fit  for  all  do- 
mestic uses,  after  a  considerable  time,  we 
have  inserted  it  for  the  benefit  of  our 
country  readers  :  When  the  yeast  is  ta- 
ken from  new  beer,  it  must  be  put  into  a 
clean  linen  bag,  and  be  laid  in  a  vessel 
half  full  of  dry,  sifted  wood  ashes ;  the 
whole  is  then  to  be  covered  to  the  thick- 
ness of  three  or  four  inches,  with  similar 
ashes,  ana  be  pressed  together.  In  this 
situation,  the  barm  should  remain  for  a 
day,  or  longer,  if  it  be  necessary  ;  when 
the  ashes  will  absorb  all  the  moisture, 
and  the  yeast  acquire  the  consistence  of  a 
thick  paste.  It  must  now  be  formed  into 
small  lumps,  or  balls ;  dried  in  a  mode- 
rate heat  ;  and  k«.  pt  in  bags,  in  an  airy, 
dry  place.  When  any  barm  is  wanted,  a 
few  of  such  balls  may  be  dissolved  in 
warm  water ;  or,  which  is  preferable,  in 
beer ;  and  they  will  answer  every  pur- 
pose of  fermentation. 

In  relation  to  this  subject,  may  be 
added  the  following  method  of  ferment- 
ing a  large  body  of  flour,  with  a  small 
quantity  of  yeast,  given  by  Mr.  James 
Stone,  of  Amport,  Hampshire.  Reperto- 
ry of  Arts. 

Suppose,  says  he,  you  want  to  bake  a 
bushel  of  bread,  and  have  not  more  than 
one  tea-spoon  full  of  yeast;  put  the  flour 
into  a  kneading  trough,  and  take  about 
three  quarters  of  a  pint  of  warm  water, 
and  the  tea  spoonful  of  yeast,  which  if 
thick  and  steady  the  better ;  put  it  into 
the  water,  and  stir  it  until  it  is  thorough- 
ly mixed;  then  make  a  hole  in  the  mid- 
dle of  the  flour  large  enough  to  contain 
two  gallons  of  water ;  pour  in  your  small 
quantity  of  yeast,  mixed  with  water  as 
above ;  then  take  a  stick,  about  two  feet 
long,  and  stir  in  some  of  the  flour,  until 


YEA 


YEA 


it  is  as  thick  as  you  would  make  batter 
for  a  pudding- ;  strew  some  of  the  dry 
flour  over  it,  and  let  it  rest  for  about  an 
hour,  for  in  that  time  you  will  find  this 
small  quantity  raised  so  that  it  will  break 
through  the  dry  Hour  which  you  shook 
over  it;  then  pour  in  about  a  quart  more 
of  warm  water,  and  stir  it  with  your  stick 
as  before,  and  leave  it  for  two  hours  more; 
you  will  find  it  rise,  or  break  through  the 
dry  flour  again;  then  add  three  quarts, 
or  a  gallon  more  of  warm  water,  and  stir 
in  the  Hour  again  ;  and  in  about  three  or 
four  hours  mix  up  the  dough,  and  cover 
it  warm.  In  four  or  five  hours  more  you 
may  put  it  into  the  oven,  and  you  will 
have  as  light  bread  as  though  you  had 
used  a  pint  of  yeast.  It  docs  not  take 
above  a  quarter  of  an  hour  more  time 
than  the  usual  way  of  baking  ;  for  there 
is  no  time  lost,  but  that  of  adding  water 
three  or  four  times.  When  you  find  your 
body  of  flour  sponged  large  enough,  be- 
fore you  put  in  the  rest  of  the  water,  yoU 
should,  with  both  hands,  mix  thai  winch 
is  spunged,  and  the  dry  flour,  altogether, 
and  then  add  the  remainder  of  warm  wa- 
ter, and  your  dough  will  rise  the  better 
and  easier.  The  author  asserts,  that  he 
constantly  bakes  this  way  ;  in  the  morn- 
ing about  six  or  seven  o'clock,  he  begins 
his  first  operation  ;  in  an  hour's  time  he 
adds  more  water;  in  two  "hours  more  a 
greater  quantity  ;  about  noon  makes  up 
the  dough,  and  about  six  in  the  evening, 
it  is  put  into  the  oven  ;  and  that  he  has 
always  good  bread,  never  heavy,  nor  bit- 
ter. He  adds,  that  the  cause  of  heavy 
bread  is  not  owing  to  the  smallness  of  the 
quantity  of  yeast  used,  but  to  its  not  be- 
ing used  properly,  for  yeast  is  to  flour 
what  fire  is  to  fuel — a  spark  of  the  latter 
will  kindle  a  large  body  by  only  blowing 
it  up  ;  so  a  thimble  full  of  the  former,  by 
adding  warm  water  to  it,  will  raise  or 
spunge  almost  any  quantity  of  flour. 

Thus  heavy  bread  is  not  owing  to  a  de- 
ficiency of  fermentation  ;  for,  if  the  dough 
is  put  into  the  oven  before  it  is  ripe,  hea- 
vy bread  is  the  natural  consequence. 

In  regard  to  the  difference  of  seasons, 
he  prescribes  that  in  summer  the  wa- 
ter should  be  blood  warm,  and  in  cold 
frosty  weather  as  warm  as  you  can  bear 
your  hand  in  it,  without  making  it  smart ; 
taking  care  in  winter  to  cover  up  your 
dough. 

The  great  importance  of  good  yeast,  to 
the  making  of  wholesome  bread,  induces 
the  editor  to  communicate  several  receipts 
which  may  be  depended  on.  Any  one  of 
them  will  answer,  but  it  ma^y  be  useful  to 
enable  a  choice  to  be  made, 
VOL.  II. 


1.  Boil  a  pint  bowl  full  of  hops,  in  two 
quai  ls  of  water,  lo  one  quart ;  put  eight 
table-spoonfuls  of  flour  into  a  pan,  and 
strain  the  hop  water  boiling  on  it ;  when 
mixed,  it  should  be  thick  batter,  and 
when  milk-warm,  stir  in  a  breakfast-cup 
of  good  yeast,  pour  it  into  three  porter  bot- 
tles, stopping  them  with  paper  ;  put  them 
in  a  milk-pan  near  the  f  ire,  and  as  soon  as 
the  mixture  rises  to  the  top  of  the  bottles, 
remove  them  to  the  cellar  until  it  sub- 
sides, then  cork  the  bottles,  and  set  them 
on  a  cool  cellar  floor,  or  in  an  ice-house. 
In  very  warm  weather,  the  corks  ought  to 
be  taken  out  every  day,  to  let  out  the 
carbonic  acid  air,  and  the  bottles  again 
stopped. 

2.  Another,  receipt  directs  the  addition 
of  a  tabie-spoonful  of  ginger,  which  is  to 
be  boiled  with  the  hops  ;  and  the  further 
addition  a  table-spoonful  of  brown  sugar 
before  the  flour  is  stirred  in. 

3.  Perpetual  Yeast.  Mix  one  pound  of 
flour  with  boiling  w  ater,  to  the  thickness 
of  gruel,  add  to  it  half  a  pound  of  brown 
sugar,  mix  them  well  together ;  put  three 
spoonsful  of  purified  yeast  into  a  large 
vessel,  upon  which  put  the  above  ingre- 
dients, which  wid  soon  ferment.  Collect 
the  yeast  off  the  top,  and  put  it  into  a 
small  necked  pot,  and  cover  it  from  the 
air ;  keep  it  in  a  dry  place,  and  moderate- 
ly warm.  When  used  in  part,  replace  it 
with  fl  jur  made  into  a  thin  paste,  and  su- 
gar, in  the  former  proportion.  It  will 
keep  for  half  a  year  or  more.  No  yeast  is 
necessary  except  the  first  time.  Colum- 
bian Magazine,  December,  1788. 

4.  Yeast  made  after  the  following  re- 
ceipt, is  said  to  be  preferable  to  any  other 
kind. 

Boil  twelve  clean  washed,  middle  sized 
potatoes  ;  and  at  the  same  time  boil,  in 
another  vessel,  a  handful  of  hops  in  a 
quart  of  water  ;  peel,  and  mash  the  pota- 
toes in  a  marble  mortar,  pour  part  of  the 
hop-water,  while  hot,  upon  the  potatoes, 
mix  them  well,  and  pass  them  through  a 
sieve  ;  {hen  add  the  remainder  of  the  hop- 
water,  and  half  a  tea-cupful  of  honey,  beat 
all  well,  and  add  a  small  portion  of  leaven 
to  bring  on  the  fermentation.  Put  the 
whole  in  a  stone  jug,  and  set  it  by  the 
fire  (in  the  winter.)  All  the  utensils  must 
be  scalded  every  time  they  are  used,  and 
washed  perfectly  clean.  One  tea-cupful 
of  the  above  potatoe  yeast*  will  answer 
for  two  quarts  of  flour.  In  summer,  the 
yeast  ought  to  be  made  every  second 
day. 

If  we  consider  the  use  of  yeast  in  rais- 
ing bread,  and  the  antiquity  of  leaven,  and 
of  course  the  relative  properties  of  each, 


YEL 


YTT 


and  their  similarity  in  effect,  a  number  of 
circumstances  must  be  considered,  in  or- 
der to  comprehend  the  causes  of  the  phe- 
nomena of  their  action. 

If  dough,  after  standing  a  sufficient 
time,  be  baked  in  the  usual  way',  it  forms 
a  Loaf  full  of  interstices,  but  of  a  taste  so 
sour  and  unpleasant,  that  it  cannot  be 
eaten.  If  a  small  quantity  of  this  old 
paste,  or  leaven,  be  mixed  with  new  made 
paste,  the  whole  begins  to  ferment  in  a 
short  time,  a  quantity  of  gas  is  evolved  ; 
but  the  glutinous  part  of  the  Hour  pre- 
vents the  gas  from  escaping.  The  paste 
therefore  swe<ls,  and  when  baked,  makes 
excellent  biead. 

The  antient  Gauls,  however,  in  relation 
to  this  subject,  as  mentioned  by  Pliny, 
made  use  of  the  barm  that  rises  on  beer, 
or  what  we  call  yeast ;  and  ever  since,  it 
ha;>  had  ihi  preference." 

Yeast  acts,  according  to  the  general 
theory,  and  particularly  the  experiments 
of  Eldm,  by  means  of  the  carbonic  acid 
gas,  which  it  contains,  or  evolves  in  the 
process  ;  for  dough,  he  observes,  when 
mixed  with  water  impregnated  w  ith  car- 
bonic acid  gas,  raises  as  well  as  with 
yeast;  and  he  adds,  that  yeast,  deprived 
of  its  carbonic  acid  or  fixed  air,  has  no 
efficacy  in  raising  bread.  But  however 
true  his  experiments  and  conclusions  may 
appear,  there  is  reason  to  suppose  from 
what  we  have  formerly  said,  that  yeast 
although  dry,  has  the  eiiect  oi  raising 
bread  when  previously  moistened;  and 
lience  if  it  be  carbonic  acid  gas,  or  some 
other  gas,  (which  undoubtedly  it  is,)  its 
formation  is  dependent  on  the  decompo- 
sition of  the  matter  itself.  Some  ingeni- 
ous experiments  on  this  subject,  were 
made  by  our  late  and  ingenious  country- 
man, Dr  Pennington. 

YELLOW  DYES.  See  Dyeing.  Be- 
sides the  different  modes  of  communicat- 
ing the  yellow  colour,  and  the  prepara- 
tion of  dyes,  we  will  add  the  following, 
called  Woulfe's  yellow  colour. 

Take  half  an  ounce  of  pulverized  indi- 
go, and  mix  it  in  a  deep  glass  vessel,with 
two  ounces  of  strong  spirit  of  nitre,  pre 
viously  diluted  with  eight  ounces  of  wa- 
ter, to  prevent  the  indigo  from  taking 
fire.  Let  this  mixture  stand  for  a  week, 
and  digest  it  in  a  sand  heat,  for  pne  or 
two  hours  •,  adding  four  ounces  of  water. 
The  solution  is  now  to  be  filtered  :  when 
mixed  with  water,  in  the  proportion  of 
one  part  of  the  former,  to  four  or  five  of 
the  latter;  and,  on  adding  a  little  alum, 
it  communicates  a  durable  yellow  co- 
lour. 

There  are  a  great  many  plants,  indige- 
nous to  our  soil,  that  are  useful  in  fur- 


nishing yellow  dyes ;  such  as  the  Hvdratis 

Canadensis,  Quercus  Tinctoria,l2'c. 

YELLOW  PIGMENTS  In  general.  See 

Co  loir  Making. 

YELLOW  INK  may  be  prepared,  by 
previously  dissolving  a  small  portion  of 
alum,  and  gum-arabic  in  pure  water,  and 
then  infusing  a  few  grains  of  dry  saffron, 
m  the  same  solution.  It  may,  likewise, 
be  obtained  by  slowly  boiling  two  ounces 
of  Avignon,  or  French  berries,  in  one 
quart  of  water,  with  half  an  ounce  of  alum, 
till  one-third  of  the  fluid  be  evaporated  ; 
when  two  drachms  of  gum-arabic,  one 
drachm  of  sugar,  and  a  similar  quantity 
of  pulverized  alum,  are  to  be  dissolved  in 
this  liquid 

YELLOW  SYMPATHETIC  INK.  See 
Ink. 

YELLOW  WEED.    See  Dyeing. 

YELLOW,  PATENT,  or  Turner's. 
See  Lead. 

YELLOW,  NAPLES.  The  Naples  Yel- 
low (Gillolino)  is  a  fine  pigment,  long- 
prepared  at  Naples,  which  has  the  appear- 
ance of  an  earth,  is  very  friable,  heavy, 
porous,  not  alterable  by  exposure  to  air, 
and  of  a  pale  orange-yellow  colour  When 
heated  it  exhales  no  sensible  vapour, 
melts  when  red-hot,  but  undergoes  no 
other  change,  except  that  the  colour  be- 
comes deeper.  Boiling  water  and  acid 
extract  a  portion  from  it,  but  do  not  dis- 
solve it  entirely. 

This  pigment  (the  preparation  of  which 
is  kept  secret  )  has  been  examined  by  se- 
veral chemists,  hut  no  accurate  analysis 
has  been  made  of  it.  Fougeroux  shewed 
that  it  was  a  metallic  oxyd,  by  reducing 
it  with  a  proper  flux,  and  easily  obtained 
a  regulus  from  it,  which  consisted  of  lead 
and  antimony.  Beckman  and  Couret  have 
confirmed  this  composition.  A  process 
which  produces  a  similar  pigment,  is  thus 
given  by  Couret.  Mix  together  twelve 
ounces  of  cerusse,  three  ounces  of  diapho- 
retic antimony,  of  alum  and  sal-ammoniac, 
each  one  ounce,  heat  them  for  a  consider- 
able heat  below  redness,  and  afterwards 
in  a  red-heat  for  three  hours  longer,  after 
which  the  mass  will  have  acquired  a  beau- 
tiful yellow  colour. 

Another  method  of  preparing  the  cele  - 
brated Naples  yellow,  is  that  or  M.  Pas- 
sery,  who  makes  use  of  the  following  in- 
gredients, namely  antimony,  one  pound  ; 
lead  one  and  an  half  pounds;  alum  and 
common  salt,  of  each  one  ounce.  We 
have  inserted  this  recipe,  on  the  authori- 
ty of  Mr.  Wiegieb  ;  who  simply  enume- 
rates the  articles  here  stated,without  com- 
municating the  process  of  compounding 
them. 

YTTKIA.    See  Earth?. 


ZIN 


ZIN 


Z 


ZAFFTCK.    See  Cobalt. 

ZAFFRE  INK.    See  Ink. 

ZINC,  or  Spel  i'Er,  Ores  of.  See  Ore. 

ZINC,  how  obtained  from  its  ores. 

The  ore,  whether  calamine  or  blende, 
after  being  raised  from  the  mine,  is  first 
dressed,  that  is  it  is  broken  to  small  pieces, 
and  the  galena,  pyrites,  and  other  impu 
rities  are  separated  as  accurately  as  pos- 
sible by  hand  ;  it  is  next  calcined  at  a 
moderately  red  heat,  in  a  reverberate  ry 
furnace,  by  which  the  calamine  is  depriv- 
ed of  its  carbonic  acid,  and  the  blende  of 
the  most  part  of  its  sulphur  It  is  then 
washed,  by  Which  the  lighter  eardiy  parts 
are  separated  from  the  metallic  oxyd, 
which  latter,  being  dried,  is  intimately 
mixed  with  one-eighth  of  its  weight  of 
charcoal,  by  grinding  the  ingredients  to- 
gether in  a  mill,  and  is  now  ready  to  be 
smelted.  The  furnace  in  which  the  re- 
duction is  performed,  is  a  circular  one 
not  unlike  that  of  a  glass-house,  in  it  are 
fixed  six  large  earthen  pots,  about  four 
feet  high,  and  nearly  of  the  same  shape 
as  oil-jars  :  into  the  bottom  of  each  pot  is 
inserted  an  iron  tube,  that  passes  through 
the  arched  door  of  the  furnace,  and  dips 
in  a  vessel  of  water  placed  beneath,  while 
the  other  end  of  the  tube  rises  within  the 
crucible,  to  within  a  few  inches  of  its  top. 
These  crucibles  are  filled  up  to  the  level 
of  the  tube,  with  the  mixture  of  roasted 
ore  and  charcoal,  the  cover  of  each  is 
very  accurately  luted  on,  and  the  furnace 
is  charg  d  with  fuel,  by  which  an  intense 
heat  is  kept  up  for  several  hours.  The 
zinc,  as  it  is  reduced,  ascends  to  the  top 
of  the  pot,  in  the  form  of  vapour,  and  there 
being  prevented  from  escaping,  by  the 
closely  luted  cover  it  descends  through 
the  central  iron  tube,  whence  it  passes 
into  the  water,  and  is  there  condensed  in 
small  drops.  These  globules  are  after- 
wards melted  and  cast  into  ingots,  in 
which  state  they  are  brought  to  mar- 
ket. 

Common  zinc  generally  contains  a  little 
lead,  copper,  arsenic,  iron,  manganese, 
and  probably  plumbago,  which  often  con- 
siderably impair  the  quality  of  the  alloys, 
into  which  it  enters.  In  order  to  get  rid, 
in  part  at  least,  of  these  impurities,  the 
common  practice  is  to  melt  the  zinc  in  a 
crucible,  and  then  stir  into  it,  by  means  of 
a  stick  or  earthen  rod,  a  mixture  of  sul- 
phur and  fat :  the  latter  of  these  preserves 
the  zinc  from  oxydation,  while  the  for- 
mer, uniting  with  all  the  metals  present, 


except  the  zinc,  converts  them  into  sul- 
phurets,  which  rising  to  the  top  form  a 
scoria  that  may  be  skimmed  olF :  this  is 
to  be  repeated,  as  long  as  any  scoria 
makes  its  appe  irance.  \1.  Proust  objects 
to  this  method  as  completely  ineffectual, 
and  proposes  anoiher,  which  is  simply  re- 
distilling the  zinc  in  an  earthen  retort; 
after  the  metal  has  passed  over,  there  re- 
mains behind,  a  mixed  mass  of  oxyds  and 
other  impurities.  But  it  is  not  very  ob- 
vious how  either  the  arsenic  or  lead  can 
be  thus  got  rid  of,  nor  does  it  by  any 
means  appear,  that  the  old  method  is  so 
very  nugatory-  It  would  probably  be  an 
improvement,  first  to  heat  the  zinc  nearly 
to  melting,  in  which  state  it  is  very  easily 
pulverizable,  and  having  thus  reduced  it 
to  fine  powder,  to  mix  it  with  about  one- 
fifth  of  its  weight  of  sulphur,  and  a  little 
pitch,  then  to  charge  an  eartnen  tvtort 
with  the  mixture,  to  keep  it  for  some 
time,  at  a  temperature  not  exceeding  that 
of  melted  lead,  and  then  to  raise  it  by 
degrees,  till  the  zinc  begins  to  be  volati- 
lized :  the  contents  of  the  retort  being 
now  allowed  to  cool  gradually,  the  puri- 
fied zinc  would  be  found  at  die  bottom, 
coveted  by  a  scoria  of  sulpnuret. 

If  however  the  zinc  is  required  of  ex- 
treme purity,  take  the  common  sulphate 
of  zinc,  (white  vitriol  of  the  shop-,)  dis- 
solve it  in  hot  water,  and  add  a  little 
sulphuric  acid  and  granulated  zinc,  by 
this  means  the  copper,  arsenic,  and  the 
principal  part  of  the  iron,  will  be  precipi- 
tated. When  the  acid  is  saturated,  pour 
oft'  the  clear  liquor,  and  evaporate  it  to 
,  dryness  ;  moisten  the  white,  salt  thus  pro- 
j  cured  with  a  little  nitric  acid,  and  heat  it 
nearly  to  redness  in  a  crucible  ;  by  this 
the  residue  of  the  iron  and  manganese, 
will  be  reduced  to  the  state  of  insoluble 
oxyd,  and  warm  water  wili  take  up  only 
the  pure  sulphate  of  zir.c.  This  is  to  be 
decomposed  by  carbonate  of  ammonia, 
and  the  white  precipitate  thus  obtained, 
after  being  washed  and  calcined,  is  to  be 
mixed  with  about  one-sixth  01  chare  oaf, 
and  reduced  by  distillation  in  the  usual 
way. 

ZINC,  Ores  of,  how  analizcd.  See 
Tests. 

ZINC,  is  a  semimetal  of  a  blueish  white 
colour,  somewhat  brighter  than  lead ;  of 
considerable  hardness,  and  so  malleable, 
as  not  to  be  broken  with  the  hammer, 
though  it  cannot  be  much  extended  in 
this  way.   It  is  very  easily  extended  by 


ZIN 


ZIN 


the  rollers  of  the  flatting-  mill.  In  a  tem- 
perature between  210°  and  300°  of  Fail r. 
it  h_s  so  much  ductility,  that  it  can  be 
drawn  into  wire,  as  laminated,  for  which 
a  patent  has  been  obtained  by  Messrs 
Hobson  and  Sylvester,  of  Sheffield  The 
zinc  thus  annealed  and  wrought,  retains 
the  malleability  it  had  acquired 

When  broken  by  bending-,  its  texture 
appeal  s  as  if  composed  of  cubical  grains. 
On  account  of  its  imperfect  malleability, 
it  is  difficult  to  reduce  it  in  o  small  parts, 
by  fiii.ig*  or  hammering  ;  but  it  may  be 
granulated,  like  the  malleable  metals,  by 
pouring  it,  when  fused,  into  cold  water  ; 
or,  if  it  be  heated  nearly  to  melting,  it 
is  then  sufficiently  brittle  to  'be  pulve- 
rized. 

It  melts  long  before  ignition,  at  about 
the  700th  degree  of  Fahrenheit's  thermo- 
ter ;  and,  soon  after  it  becomes  red-hot, 
it  burns  with  a  dazzling  white  flame,  of  a 
blueish  or  yellowish  tinge,  and  is  oxyded 
with  such  rapidity,  that  it  files  up  in  the 
form  of  white  flowers,  called  the  flowers 
of  zinc,  or  philosophical  wool.  These  are 
generated  so  plentifully,  that  the  access 
of  air  is  soon  intercepted  ;  and  the  com- 
bustion ceases,  unless  the  matter  be  stir- 
red, and  a  considerable  heat  kept  up. — 
The  white  oxyd  of  zinc  is  not  volatile, 
but  is  driven  up  merely  by  the  force  of 
the  combustion.  When  it  is  again  urged 
by  a  strong  heat,  it  becomes  converted 
into  a  clear  yellow  glass.  If  zinc  be  heat- 
ed in  closed  vessels,  it  rises  without  de- 
composition. Zinc  appears  to  be  the 
most  volatile  of  metallic  substances,  ex- 
cept arsenic. 

The  diluted  sulphuric  acid  dissolves 
zinc  :  at  the  same  time  that  the  tempera- 
tune  of  the  solvent  is  increased,  and  much 
hydrogen  escapes,  an  undissolved  residue 
is  left,  which  has  been  supposed  to  con- 
sist of  plumbago.  Proust,  however,  says, 
that  it  is  a  mixture  of  arsenic,  lead,  and 
copper.  As  the  combination  of  the  sul- 
phuric acid,  and  the  oxyd  proceeds,  the 
temperature  diminishes,  and  the  sulphate 
of  zinc,  which  is  more  soluble  in  hot  than 
cold  water,  begins  to  separate,  and  dis- 
turb the  transparency  of  the  fluid.  If 
more  water  be  added,  the  salt  may  be 
obtained  in  prismatic  four-sided  crystals. 
The  white  vitriol,  or  copperas,  usually 
sold,  is  crystallized  hastily,  in  the  same 
manner  as  loaf-sugar,  which  on  this  ac- 
count it  resembles  in  appearance  :  it  is, 
slightly  efflorescent.  The  white  oxyd  of 
zinc  is  soluble  in  the  sulphuric  acid,  and 
forma  the  same  salt  as  is  afforded  by  zinc 
itself. 

The  hydrogen  gas,  that  is  extricated 
from  water,  by  the  action  of  sulphuric 


acid,  carries  up  with  it  a  portion  of  zinc, 
which  is  apparently  dissolved  in  it;  but 
this  is  deposited  spontaneously,  at  least 
in  part,  if  not  wholly  by  st  anding.  It  burns 
u  ith  abi  ighter  flame  than  common  hydro- 
gen 

Sulphate  of  zinc,  or  white  vitriol,  is 
prepared  in  the  large  way  from  some  va- 
rieties of  the  native  sulphuret.  The  ore 
is  roasted,  wettt  d  with  water  and  exposed 
to  the  air  The  sulphur  attracts  oxygen, 
and  is  converted  into  sulphuric  acid  ;  and 
the  metal,  being  at  the  same  time  oxyded, 
combines  with  the  acid.  After  some  time 
the  sulphate  is  extracted  bj  solution  in 
water;  and  the  solution  being  evaporated 
to  dryness,  the  mass  is  run  into  moulds. 
This,  the  white  vitriol  of  the  shops,  ge- 
nerally contains  a  small  portion  of  iron, 
and  sometimes  of  lead 

Sulphurous  acid  dissolves  zinc,  and 
sulphuretted  hydrogen  is  evolved.  The 
solution,  by  exposure  to  the  air,  deposits 
needly  crystals,  which,  accordingto  Four-" 
croy  and  Yauquclin, are  sulphuretted  sul- 
phite of  zinc.  By  dissolving  oxule  of  zinc 
in  sulphuirms  acid,  the  pure  sulphite  is 
obtained.  This  is  soluble,  and  crystalli- 
zable. 

Diluted  nitric  acid  combines  rapidiy 
with  zinc,  and  produces  much  heat,  at  the 
same  time  that  a  large  quantity  of  nitrous 
air  flies  off.  The  solution  is  very  caustic, 
and  affords  crystals  by  evaporation  and 
cooling,  which  slightly  detonate  upon  hot 
coals,  and  leave  oxyde  of  zinc  behind. — 
This  salt  is  deliquescent. 

Muriatic  acid,  acts  very  strongly  upon 
zinc,  and  disengages  much  hydrogen ; 
the  solution,  when  evaporated*  does  not 
|  afford  crystals,  but  becoms  gelatinous. 
By  a  strong  heat  it  is  partly  decomposed, 
a  portion  of  the  acid  being  expelled,  and 
part  of  the  muriat  sublimes  and  condenses 
in  a  congeries  of  prisms. 

Zinc  is  soluble  in  other  acids  ;  but  these 
combinations  are  not  used  in  the  arts. 
Besides  uniting  with  different  acids,  it 
combines  with  some  of  the  inflammables, 
ami  w -ii.il  otlter  metals.  Although  we 
have  noticed  one  of  its  combinations, 
namely,  brass,  yet  we  deem  it  useful,  to  * 
a  portion  of  our  artists,  to  give  a  more 
practical  treatise  on  the  subject  of  the 
brass  foundery.  This  very  important  al- 
loy of  zinc  and  copper,  is  treated  at  large 
in  several  excellent  works.  Messrs.  Ai- 
kins,  in  their  Chemical  and  Mineralogical 
Dictionary,  have  enumerated  several  pro- 
cesses, and  have  added  some  useful  ob- 
servations, which  we  here  use. 

It  is  wot  easy  to  obtain  a  perfect  union 
of  zinc  and  copper  by  mere  f  usion  in  open 
vessels,  for  at  a  heat  Jess  than  is  required 


ZIN 


7IN 


to  melt  the  copper,  the  zinc  readily  takes 
fee,  and  much  of  it  burns  oft' before  it  has 
time  to  mix  with  the  metal,  so  that  the  pro- 
portion of  zinc  is  constantly  lessening;  by 
volatilization.  Even  after  both  metals  arc 
fused,  the  zinc  continues  to  burn  off  in 
uncovered  vessels,  and  at  last  scarcely 
any  thing  but  copper  would  be  ltft  In 
order  therefore  to  combine  copper  most 
intimately  with  zinc,  and  yet  to  preserve 
its  malleability,  the.  ingenious  process  of 
cementation  has  been  resorted  to,  in  the 
manufacture  of  brass,  which  is  performed 
by  heating  in  a  covered  pot,  alternately 
layers  of  copper  in  small  pieces,  with  zinc 
ore  and  charcoal,  and  continuing'  the  fire 
till  the  copper  is  thoroughly  impregnated 
with  the  tine. 

Zinc  Weing  a  volatile  metal,  can  only 
be  procured  from  its  ores  by  sublimation  : 
the  process  for  obtaining  it  (which  is 
described  more  at  length  under  that  arti- 
cle) being  to  heat  strongly  a  mixture  of 
its  ore  with  charcoal,  in  a  vessel  closed 
on  all  sides,  except  where  it  admits  a 
tube,  the  lower  end  of  which  dips  in  wa- 
ter. As  soon  as  the  charcoal  reduces  the 
oxyd,  the  metal  rises  in  vapour  through 
the  tube,  and  condenses  in  the  water  be- 
low. A  similar  reduction  takes  place  in 
brass-making,  only  the  vapour  of  the 
zinc,  instead  of  being  conveyed  out  of  the 
crucible  in  which  it  is  formed,  unites  with 
the  copper  enclosed  in  the  same  vessel, 
and  the  whole  melts  down  into  brass.  A 
less  heat  is  required  in  brass-making,  than 
that  which  fuses  copper,  the  zinc  being 
able  to  penetrate  the  copper  when  tho- 
roughly red  hot,  and  melting  it  down  as 
soon  as  it  becomes  brass. 

Brass  is  manufactured  in  many  coun- 
tries. 

The  ores  of  zinc,  are  several  species  of 
calamine  and  of  blende,  called  by  the  mi- 
ners Black  Jack. 

These  are  chiefly  oxyds,  or  carbonated 
oxyds  of  zinc,  and  require  a  previous  cal- 
cination before  they  are  fit  for  brass  mak- 
ing. 

At  Holywell,  in  Flintshire,  the  cala- 
mine which  is  received  raw  from  the 
mines  in  the  neighbourhood,  is  first  pound- 
ed in  a  stamping  mill,  and  then  washed 
and  sifted  in  order  to  separate  the  lead, 
with  which  it  is  largely  admixed.  It  is 
then  calcined  on  a  broad,  shallow  brick 
hearth,  over  an  oven  heated  to  redness, 
and  frequently  stirred  for  some  hours.  In 
some  places  a  conical  pile  is  composed  of 
horizontal  layers  of  calamine,  alternating 
with  layers  of  charcoal,  the  whole  rest- 
ing on  a  layer  of  wood,  in  large  pieces, 
with  sufficient  intervals  for  the  draught 
of  air.   It  is  then- kindled,  and  the  stack 


continues  to  burn  till  the  calamine  is  tho- 
roughly calcined.  The  calamine  thus 
prepared,  is  then  ground  in  a  mill,  and  at 
the  same  time  mixed  with  about  a  third 
or  a  fourth  part  of  charcoal,  and  is  then 
ready  for  the  brass  furnace.  In  some  pla- 
ces pit-coal  is  ground  with  the  calamine, 
instead  of  charcoal,  but  this  is  found  t» 
injure  the  malleability  of  the  brass  ob- 
tained. 

The  brass-furnace  has  the  form  of  the 
frustum  of  a  hollow  cone,  or  a  cone  with 
the  apex  cut  off  horizontally.  At  the 
bottom  of  the  furnace  is  a  circular  grate, 
or  perforated  iron  plate,  coated  with  clay 
and  horse-  dung,  to  defend  it  from  the  ac- 
tion of  the  fire.  The  crucibles  stand  up- 
on the  circular  plate,  forming  a  circular 
row  with  one  in  the  middle  The  fuel, 
which  is  coal,  is  thrown  round  the  cruci- 
bles, being  let  down  through  the  upper 
opening  or  smaller  end  of  the  cone.  Over 
this  opening  is  a  perforated  cover  made 
of  fire  bricks  and  clay,  and  kept  together 
with  bars  of  iron,  so  as  to  fit  closely.  This 
cover  serves  to  regulate  the  heat  in  the 
following  manner  :  The  draught  of  air  is 
formed  through  an  under-ground  vault  to 
the  ash  hole,  thence  through  the  grate 
and  round  the  crucibles,  and  through  the 
smaller  upper  opening  into  an  area,  where 
the  workmen  stand,  which  is  covered  by 
a  large  dome,  and  a  chimney  to  comey 
the  smoke  into  the  outer  air.  When  the 
draught  is  the  strongest,  and  the  heat  is 
required  of  the  greatest  intensity,  the  co- 
ver is  entirely  removed  and  the  flame 
then  draws  through  the  upper  opening  of 
the  furnace  to  a  considerable  height,  in- 
to the  outer  brick  dome ;  when  the  heat 
is  to  be  lessened,  the  cover  is  put  on, 
which  intercepts  more  or  less  of  the 
draught  from  the  furnace,  as  more  or  few- 
er of  the  holes  of  the  cover  are  left  un- 
stopped. 

The  crucibles  are  charged  with  the 
mixed  calamine  and  charcoal,  together 
with  copper  clippings  and  refuse  bits  of 
various  kinds,  and  sometimes  brass  clip- 
pings also,  most  of^vhich  are  previously 
melted  and  run  into  a  small  sunk  cistern 
of  water,  through  a  kind  of  cullender, 
which  divides  the  metal  into  globules, 
like  shot.  Powdered  charcoal  is  put  over 
all,  and  the  crucibles  are  then  covered 
and  luted  up  with  a  mixture  of  clay,  or 
loam,  and  horse-dung. 

The  time  required  for  heating  the  cru- 
cibles, and  compleating  the  process,  va- 
ries considerably  in  different  works,  be- 
ing determined  by  custom,  by  the  quan- 
tity of  materials,  the  size  of  the  crucibles, 
and  especially  the  nature  of  the  calamine. 
In  the  great  way,  from  ten  to  twenty -four 


ZIN 


zm 


hours  are  required.  At  Holywell,  in  Flint- 
shire, about  twenty-four  hours  are  ta- 
ken. 

During  the  process,  and  especially  to- 
wards the  latter  end,  part  of  the  reduced 
zinc  which  escapes  absorption  by  the  cop- 
per, finds  it  way  in  vapour  through  the  lu- 
ting of  the  crucible  lids,  and  burns  around 
them  with  the  beautiful  blue  flame,  and 
dense  white  smoke,  peculiar  to  this  me- 
tal ' 

The  heat  required  for  brass-making  is 
somewhat  less  than  what  would  be  neces- 
sary to  melt  large  masses  of  copper,  brass 
being  the  more  fusible  of  the  two,  and,  as 
it  should  seem,  the  vapour  of  zinc  being 
able  to  penetrate  copper,  as  soon  as  it  is 
softened  by  a  full  red  heat.  When  the 
brass  is  judged  to  be  complete,  and  the 
saturation  of  the  copper  with  zinc  to  be 
as  high  as  possible,  the  heat  is  increased  to 
melt  the  whole  down  into  one  clean  mass 
at  the  bottom,  the  crucibles  are  taken  out 
and  the  metal  poured  into  moulds.  At 
Holywell,  out  of  the  six  crucibles  used  to 
one  furnace,  the  quantity  of  brass  obtain- 
ed, is  about  as  much  as  would  fill  one  of 
them.  This  makes  in  subsequent  manu- 
facture, a  single  large  plate,  which  is  ma- 
nufactured in  the  same  way  as  copper- 
plate. Or,  more  accurately,  from  forty 
pounds  of  copper,  and  sixty  pounds  of  ca- 
lamine, about  sixty  pounds  of  brass  are 
obtained,  besides  the  loss  of  a  good  deal 
of  zinc,  by  the  unavoidable  escape  of  much 
of  it  in  form  of  vapour  ihrough  the  pores 
of  the  lute  or  the  crucible  covers. 

The  above  is  the  usual  process  of  brass 
making,  and  is  essentially  the  same 
wherever  this  alloy  is  manufactured,  but 
with  some  variation  as  to  the  choice  of  in- 
gredients, their  proportions,  the  time  of 
fusion,  the  shape  ot  the  furnace,  and  other 
smaller  circumstances. 

At  Goslar,  in  Saxony,  where  brass  is 
largely  made,  the  zinc  is  furnished,  not  by 
a  native  Calamine,  but  the  cad?niator  sub- 
limed oxyd  of  zinc,  which  is  collected  for 
this  purpose  in  a  particular  part  of  the 
chimnies  of  the  reverberaiory  furnaces,  in 
which  the  Saxon  lead  ores  and  blendes 
are  roasted. 

A  great  variety  obtains  in  the  respect- 
ive proportions  of  the  ingredients.  Ac- 
cording to  Swedenborg,  they  are,  in  Gos- 
lar, 30  parts  of  copper,  40  to  45  of  cad- 
mia,  and  twice  the  volume  of  charcoal ;  at 
Paris,  and  in  many  of  the  French  manu- 
factories, they  are,  35  of  copper,  35  of*  old 
brass,  40  of  calamine,  and  20  to  25  of 
charcoal ;  in  Sweden,  30  of  copper,  20  to 
30  of  old  brass,  and  46  of  calamine,  with 
charcoal  sufficient ;  or,  40  of  copper,  30 
of  old  brass,  and  60  of  calamine  ;  and  in 


England,  generally  about  40  of  copper  and 
60  of  calamine.  The  product  of  brass  va- 
ries also,  but  it  seems  to  be  in  few  pla- 
ces so  great  as  in  some  of  the  English 
works,  where,  as  already  mentioned,  40 
pounds  of  copper  become  in  the  process 
60  pounds  of  brass.  This  superior  quan- 
tity is  ascribed  partly  to  the  goodness  of 
the  calamine,  and  partly  to  the  smallness 
to  which  the  copper  is  previously  reduced 
by  being  poured  melted  into  cold  water, 
and  thus  affording  a  great  surface  of  me- 
tal to  the  action  of  the  zinc  vapour. 

At  Stolberg,  near  Aix-la-Chapelle, 
where  brass  is  very  largely  manufactured, 
the  furnaces  are  cylindrical,  and  each 
contains  eight  crucibles  arranged  in  two 
tiers,  of  four  each.  These  crucibles  are 
fifteen  inches  high,  twelve  inches  deep, 
and  eight  or  nine  inches  wide.  The  pro- 
portions of  ingredients  are  forty  pound  of 
copper,  sixty -five  pound  of  calamine,  and 
double  its  volume  of  charcoal.  After  the 
fire  has  been  kept  up  for  twelve  hours, 
the  crucibles  are  uncovered,  and  a  work- 
man takes  off,  with  an  iron  trowel,  all  the 
scum  and  charcoal,  which  swim  upon  the 
liquid  metai,  and  which  is  called  arkest. 
When  examined  with  a  glass,  this  is  found 
to  consist  of  calamine  and  copper  parti- 
cles, cohering  together,  but  not  complete- 
ly united  The  brass  resulting  from  this 
process  is  coarse,  brittle,  and  unequal  in 
texture,  and  requires  a  second  fusion  be- 
fore it  is  fit  for  use.  For  this  purpose  the 
same  crucibles  are  employed,  and  are 
filled,  first  with  three  handfuls  of  the  mix- 
ture of  calamine  and  charcoal,  over  which 
are  put  two  or  three  pounds  of  the  impure 
brass,  broken  in  pieces,  then  more  cala- 
mine and  charcoal,  with  a  lump  of  the  ar- 
kest, and  over  all,  calamine  and  charcoal 
powder.  The  crucible  is  then  strongly 
heated  for  two  hours,  after  which  the 
brass  is  fit  to  be  cast  into  plates,  which  is 
done  here  in  the  following  manner.  A 
mould  is  formed  of  two  blocks  of  granite, 
five  feet  long,  three  and  a  half  broad,  and 
eight  inches  thick.  They  are  placed  one 
above  the  other,  the  upper  one  being  only 
moveable,  and  furnished  with  a  tackle  and 
pullies  for  that  purpose,  and  before  cast- 
ing, the  surface  is  smeared  with  cow-dung. 
To  give  the  plate  the  requisite  thickness, 
hoops  of  iron,  of  different  dimensions,  are 
adapted  to  the  under  stone,  so  as  to  con- 
fine a  determinate  quantity  of  melted  me- 
tal. The  stones  are  then  gently  inclined, 
and  the  melted  brass  let  in  between  them. 
These  plates  are  afterwards  laminated — 
some  of  them  are  cut  into  slips  by  strong 
shears,  for  the  further  purpose  of  being 
drawn  into  wire,  and  otherwise  manufac- 
tured in  various  ways. 


ZIN 


7AN 


A  single  process,  where  the  fire  is  kept 
Op  long  enough,  and  the  materials  are 
good,  is  certainly  sufficient  to  make  good 
malleable  brass,  but  it  m  probable  that 
the  excellen«e  and  beauty  of  the  article, 
are  improved  by  making-it  undergo  a  se- 
cond cementation,  with  fresh  calamine 
and  charcoal. 

In  the  laboratory,  brass  may  be  made 
very  well,  in  the  small  way  in  a  much 
shorter  time  l'ut  into  a  crucible  a  mix- 
ture of  calamine  and  charcoal,  bury  it  in 
the  requisite  proportion  of  copper  shot, 
cover  the  whole  with  charcoal  powder, 
lute  on  a  cover  to  the  crucible,  and  heat 
slowly  in  a  wind-furnace  for  half  an  hour, 
till  the  zinc  begins  to  burn  off  in  a  blue 
flame,  round  the  top  of  the  crucible,  then 
raise  the  fire  and  heat  briskly,  for  half  an 
hour  longer. 

This  process  of  cementation  is  also  neat- 
ly shown  by  the  following  management, 
as  given  by  Cramer.  Put  the  mixture  of 
calamine  and  charcoal  into  a  crucible,  co- 
ver it  with  a  thin  layer  of  clay,  over  which 
when  dry,  lay  a  thin  plate  of  copper,  co- 
ver the  whole  with  fine  charcoal  pow  der, 
and  lute  on  a  cover  to  the  crucible.  Ap- 
ply heat  gradually,  and  the  vapour  of  the 
reduced  zinc,  will  rise  through  the  floor 
of  clay,  penetrate  the  red-hot  copper  plate 
above  it,  and  gradually  convert  it  into 
brass,  which  at  the  end  of  the  operation, 
will  be  found  lying  melted  on  the  stratum 
of  clay.  The  increase  of  weight  gained 
by  the  copper  in  this  operation  will  afford 
a  good  practical  test  of  the  goodness  of 
the  calamine,  and  its  fitness  for  brass- 
making  in  the  great  way. 

The  most  important  properties  of  brass 
compared  with  copper,  are  the  following  : 
the  colour  of  brass  is  much  brighter,  and 
more  approaching  to  that  of  gold  ;  it  is 
more  fusible  than  copper  ;  less  subject  to 
rust,  and  to  be  acted  on  by  the  vast  va- 
riety of  substances  which  corrode  copper, 
with  so  much  ease  ;  and  it  is  equally  mal- 
leable when  cold,  and  more  extensible 
than  either  copper  or  iron,  and  hence  is 
well  fitted  for  fine  wire.  Brass  however 
is  only  malleable  when  cold.  Hammer- 
ing is  found  to  give  a  magnetic  property 
to  brass,  perhaps,  however,  only  arising 
from  the  minute  particles  of  iron  beaten 
off  the  hammer,  during  the  process,  and 
forced  into  the  surface  of  the  brass,  but 
this  circumstance  makes  it  necessary  to 
employ  unhammered  brass  lor  compass- 
boxes,  and  similar  apparatus. 

Some  kinds  of  very  fine  brass,  are  said 
not  to  be  made  by  cementation,  in  the 
way  already  described,  but  by  a  more 
speedy  and  direct  union  of  copper  and 
zinc,  care  being  taken  to  prevent  the  ac- 


cess of  air,  to  the  materials  while  in  fu- 
sion. Very  fine  brass  may  also  be  made, 
by  mixing  together  the  oxyds  of  copper 
and  zinc,  and  reducing  them  with  a  car- 
bonaceous flux.  This  idea  is  ingenious, 
and  from  the  intimate  mixture  of  the  two 
metals,  which  it  promises,  it  deserves  to 
be  further  pursued.  Sage  gives  the  fol- 
lowing experiment,  to  this  purpose.  Mix 
together  50  grains  of  the  oxyd  of  copper, 
remaining  after  the  distillation  of  verdi- 
gris, (which  is  very  pure)  w  ith  100  grains 
of  lapis  calaminaris,  400  grains  of  black 
Mux,  and  30  grains  of  charcoal  powder; 
melt  the  mixture  in  a  crucible  till  the 
blue  flame  is  seen  no  longer  round  the  lid 
of  the  crucible,  and  when  cold,  a  fine  but- 
ton of  brass  is  found  beneath  the  scoria, 
weighing  a  sixth  more  than  the  copper 
alone,  obtainable  from  its  oxyd  in  the  same 
way,  but  without  the  calamine.  This 
brass  has  a  very  fine  colour  like  gold.  See 
Alloys  of  Copper. 

Zinc  is  used  in  China  as  coin,  and  is 
employed  as  a  substitute  for  tin,  in  lining 
vessels. 

An  useful  substitute  for  white-lead,  in 
painting  houses,  has  lately  been  discover- 
ed in  zinc,  by  M.  de  Morveau.  fie  di- 
rects this  mineral  to  be  calcined  in  a 
crucible,  placed  horizontally  in  the  cavity 
usually  made  for  retorts,  in  reverberatory 
furnaces.  The  oxyd  thus  obtained,  is 
then  to  be  washed  in  water,  with  a  view- 
to  separate  such  particles,  as  may  not 
have  been  perfectly  calcined;  and  When 
it  is  reduced  to  powder,  a  small  portion 
of  earth  of  alum,  or  chalk,  must  be  add- 
ed; in  order  to  give  it  a  body.  When 
this  pigment  is  to  be  used,  it  will  be  ne- 
cessary to  form  the  powder  into  a  heap, 
leaving  a  small  hole  in  the  middle,  into 
which  oil  must  be  gradually  poured,  till 
it  be  reduced  to  a  proper  consistence  ; 
when  the  paint  should  be  laid  on,  with  a 
soft  brush.  The  whitest  drying  oil  must 
be  procured,  such  as  that  obtained  from 
poppies,  if  a  white  paint  be  designed  ;  be- 
cause coloured  oil  imparts  a  tinge,  that 
impairs  its  whiteness  ;  but,  if  a  yellowish 
or  other  shade  be  intended,  any  drying 
oil  will  answer  the  purpose.  M.  Mor- 
veau observes,  that  such  paint  is  perfectly 
harmless,  emitting  no  hurtful  effluvia ; 
and  though  it  does  not  dvy  so  speedily,  as 
that  prepared  of  white-lead,  yet  it  is  not 
only  more  wholesome,  but  also  eventuallv 
cheaper ;  as  a  smaller  portion  of  zinc  will 
be  required. 

In  March,  1796,  a  patent  was  granted 
to  Mr.  John  Atkinson,  for  his  invention  of 
a  white  paint,  prepared  from  zinc,  which 
may  serve  as  a  substitute  for  that  of  w  hite- 
lead.   He  directs  the  former  mineral  to 


ZIN 


ZIN 


be  first  submitted  to  a  reverberatory  fur- 
nace, for  six  hours  ;  in  order  to  disperse 
all  the  ferruginous  particles  which  it  may 
contain.  Next,"  the  zinc  is  to  be  reduced 
to  powder,  by  the  action  of  a  mill,  and 
mixed  with  one-eighth  part  of  pulverized 
charcoal,  by  weight  ;  after  which  it  must 
be  removed  to  a  close  or  muffled  furnace, 
provided  with  two  apertures,  one  on  each 
side,  "and  (as  the  patentee  expresses 
himself,)  dilated  at  the  end  from  the  fur- 
nace, by  a  distance  of  about  20  feet the 
other  end  joining-  the  body  of  the  furnace: 
such  apertures  should  each  be  furnished 
with  a  door  at  the  farthest  extremity,  and 
which  ought  to  be  sufficiently  large  to 
admit  a  man  to  enter,  for  the  purpose  of 
collecting  the  colour.  Thus  the  zinc  must 
be  introduced  into  the  furnace,  through 
the  top  or  upper  part-  when  it  becomes 
red-hot  throughout,  a  large  dense  white 
cloud,  with  a  bright  blue  flame,  will  pass 
into  the  receptacles  or  apertures  above- 
mentioned,  where  it  will  collect  in  the 
form  of  a  pure,  white  metallic  calx. 
The  oxyd  of  zinc  is  now  to  be  diluted 


with  water,  and  ground  and  triturated  in 
a  proper  mill :  from  this  machine  it  is 
conducted,  by  means  of  gutters  or  spouts 
into  fine  sieves,  whence  it  passes  into  se- 
veral cisterns  full  of  water,  communicat- 
ing with  each  other,  by  similar  gutters  ; 
so  that  the  finest  particles  float  into  the 
farthest  reservoirs.  After  standing  about 
24  hours,  the  water  may  be  drawn  off,  and 
the  colour  collected  into  pans,  receivers, 
or  other  vessels,  capable  of  bearing  heat, 
in  which  they  are  dried;  and  in  this  state, 
the  paint  will  be  ready  tor  sale  ;  but  pre- 
viously to  its  application,  it  ought  to  be 
properly  levigated. 

According  to  M.  Rinman,  a  £ne  green 
colour  for  painters  maybe  procured,  from 
the  oxydes  of  cobalt  and  zinc.  He  directs 
any  portion  of  cobalt-ore  to  be  dissolved 
in  the  nitro-muriatic  acid  (aqua  regia) 
and  to  be  mixed  with  half  that  quantity 
ofnitrntof  zinc:  a  lixivium  of  pot-ash  is 
then  to  be  added  ;  and  when  the  precipi- 
tate is  ignited  to  whiteness,  it  will  be  fit 
for  use 

ZIRCON.    See  Earth- 


FINIS. 


i 


Weaving-. 


tJZhuuxm  Dei. 


rftmlawtm/ir 


Weaving. 


TABLE 

OF 

SUBJECTS  TREATED  OF: 

WITH 

THEIR  TECHNICAL  AND  COMMON  NAMES. 


VOLl 

A. 

Acetous  Acid  or  Distilled  Vinegar,  and 
under  the  heud  Acids — all  other  acids 
connected  with  manufactures. 

Adulteration. 

Affinity,  or  Attraction. 

Agriculture 

Alabaster. 

Alcarrazas,  or  Earthen  Wine  Coolers. 

Alcohol — Spirit  of  Wine- 

Alkalies  and  Alkaline  Earths.    See  also 

Earths. 
Alkanet,  a  Dye  Root. 
Alum 

Alumine.    See  Earths. 
Amadou  a  species  of  tinder. 
Amber  and  Amber  Grease. 
Ammonia.    See  \lkalies. 
Ampelites,  Cannel  or  Candle  Coal. 
Animals  Domestic. 

Annealing,  softening  of  Metallic  Substan- 
ces. 

Anotta,  Annotto  or  Arnotto. 
Antimony  and  its  combinations. 
Aqueduct. 

Aquafortis — Nitrous  Acid  (diluted.) 
Aqua  Tinta.    See  Engraving. 
Archella  or  Turnesol.    See  Litmus. 
Argentum  Mosaicum,  a  metallic  alloy  for 

silvering. 
Argol  or  Tartar. 

Armenian  Bole,  or  Terra  Sigillata. 
Armenian  Stone,  or  Blue  Ochre. 
Arrack,  or  Rack, a  spirituous  liquor. 
Arrow  Grass. 

Arrow-Head,  an  esculent  root. 
Arrow  Root,  Marata  JLrundinacea. 
Arsenic. 

Artichoke.    See  Kitchen  Garden. 
Ashes. 

Assay,  or  Essay. 
Astringent. 


ME  I. 

B 

Bacon,  cured  flesh  of  Swine. 

Baking. 

Bank  Fence,  in  rural  CEconomy. 
Banks,  of  Rivers. 

Barrilla,  a  Spanish  plant  which  produces 

the  Mineral  Alkali.    See  Soda. 
Bark,  black  oak. 

Basalt  or  Basaltes,  a  species  of  crystal. 
Basket  Salt,  mode  of  making. 
Bay  Salt.    See  Salt. 
Bee,  on  the  management  of. 
Bees  Wax.    See  Wax. 
Beech  Mast  Oil,  mode  of  making. 
Beef,  mode  of  curing. 
Beer,  mode  of  making,  extemporaneous t 
&c. 

Beet.  See  Sugar,  see  also  Kitchen  Garden. 
Berne  Machine,  an  Engine  for  Rooting  up 

trees. 
Biscuit.    See  Bread. 
Bismuth  or  Tin-Glass — a  semimetal. 
Bird-lime. 

Bitumen,  an  inflammable  mineral  sub- 
stance. 

Blacking,  mode  of,  making  Frankford 

Blacking,  &c. 
Blanching.  5     See  also  Appendix  and 
Bleaching.  £  Plates. 

Boilers,  construction  of  different  kinds. 
Boiling. 

Borax,  Sub-borat  of  Soda. 
Brandy. 

Brass,  also  Zinc  and  Copper. 
Bread. 

Breeding  of  Cattle,  Sheep,  &C 

Breeding  of  Fish. 

Brc  wing. 

Bricks. 

Bricklayers. 

Brick  Water. 

Brine  or  Pickle. 


TABLE  OF 


Broad  Cast  in  Husbandry. 
Bronze- 

Brunswick  Green.   See  Colour  Making. 

Building. 

Butter. 

C. 

Calamine,  Ore  of  Zinc. 
Calcination. 

Calico  Printing".    See  Printing". 
Calx.    See  Lime. 
Camphor. 

Cannel  Coal.    See  Ampelites. 

Canal. 

Candle. 

Caoutchouc.    See  also  Indian  Rubber. 
Carmine.  See  Cochineal  and  Colour  Mak- 
ing. 

Carpet  Making.    See  Weaving. 
Carrot.    See  Kitchen  Garden,  see  also 
Brandy. 

Carthamus,  Safflovver  or  Bastard  Saff  ron. 
Case  Hardening. 
Castor  Oil. 

Catechu.   See  Tannin. 
Cattle.  See  Animals  Domestic,  also  Breed- 
ing of  Cattle. 
Cedar,  Pinus  Cedens. 
Cieling. 
Cement. 

Cement  Calcareous. 

Cerusse,  or  White  Lead.    See  Lead. 

Chalcedony. 

Chalk.    See  Lime. 

Charcoal. 

Cheese. 

Chesnut  Castanea. 
Chrome,  an  Acidifiable  Metal. 
Cinnabar.    See  Mercury. 
Cisterns. 

Citric  Acid,  Acid  of  Lemons. 
Clarification.    See  Filtration  and  Wine. 
Clay.    See  Agriculture,  Brick,  Earths  and 
Alumine. 

Cloth  Making.  See  Manufacture  of  Cloth. 
Clover. 

Coak.    See  Coal. 

Coal. 

Cobalt. 

Cocculus  Indicus,  Indian  Berry. 
Cochineal. 
Colouring  Matter. 
Colour  Making. 
,  Compost.    See  Agriculture  and  Manure. 
Conductors,  Lightening  Rods. 
Copal.    See  also  Varnish. 
Copper. 

Copperas.    See  also  Iron. 
Corn.    See  Agriculture. 
Cotton. 
Cream. 

Crucible.    See  Pottery. 
Cutlery. 


Cyder. 
Cyderkin. 
Cyder  Spirit, 

D. 

Dairy  House. 

Digester. 

Distillery. 

Dog.    See  Animals  Domestic. 
Dragon's  Blood,  a  Resin. 
Draining.    See  also  Agriculture- 
Drilling,  in  Husbandry. 
Drying  Oil. 
Dyeing,  art  of. 

E. 

Earths. 

Earthen  Ware.    See  Potter)'- 

Ebony. 

Emery. 

Enamel,  or  Enamelling. 

Engines  for  raising  water. 

Engine,  Steam     See  Steam  Engine. 

Engraving,  on  Copper,  Wood,  Glass,  &c 

Epeom  Salt,  Sulphate  of  Magnesia. 

Essential  Oils.    See  Oils  Essential,  also 

Distilling. 
Essential  Oil  Varnish.    See  Varnish. 
Etching  on  Copper  and  Stone 

  on  Glass.     See  Engraving  on 

Glass. 

Extract. 

F. 

Fallowing  of  Land.    See  Agriculture. 
Farming.    See  Agriculture. 
Farriery,  art  and  profession  of. 
Fascets  in  Glass  Making.    See  Glass. 
Fawn  Colour.    See  also  Dyeing. 
Feathers 

 Dyeing  of.   See  Dyeing. 

Felt. 

Fermentation,  Vinous. 

Fermented  Liquors. 

Fernambuco  Wood.    See  Dyeing. 

Ferrits,  among  Glass  Makers. 

Ferrittes.    See  Glass. 

Fernstein.    See  Flint. 

Files  of  Stoneware. 

Filtration. 

Fine  Stiller. 

Fire  Damp. 

Fire-places. 

Firing  Iron,  in  Farriery.    See  Farriery. 
Fish  Soap.    See  also  Soap. 
Fish  Oil,  to  purify. 

Flakes  in  Colour.    See  Colour  Making. 

Flax.    See  Agriculture. 

Flint. 

Floors  Earthen. 

Flour. 

Flummery, 


SUBJECTS  TREATED  OF. 


Fluor  Spar  and  its  uses,  or  Derbyshire 
spar,  Fluate  of  Lime. 

Fh  Bto»$. 
Flics  to  destroy. 

Foil     See  also  Foliating1  and  Silvering. 
Foliating1  of  Looking  Glasses.    See  also 
Glass  Making. 

Foiling  of  Globe  Looking  Glasses. 
Foundery,  in  Metallurgy. 
Frankford  Black. 
Freezing-. 

French  Chalk.    See  Steatite. 
French  Berries,  llhamnus  infectorius. 
Friction. 

Fritt  in  Glass  Making.    See  Glass. 

Fruits,  colours  from. 

Fuel,  GSconomy  in. 

Fuliginous  Vapours,  Smoky  Vapours. 

Fuller's  Earth.    See  Earth,  Fuller's. 

Fulling1. 

Furnace. 

Fustet,  Rhus  Cotinus. 
Fustic  or  Morus  Tincloria.  See  also  Dye- 
ing. 

G. 

Galena,  Sulphuret  of  Lead,Blue  Lead  Ure. 
Galls  or  Gall-nuts,  Quercus  Cerris,  (Lin- 

naeus.)    See  Lead. 
Gallic  Acid,  Acid  of  Galls. 
Galling1.    See  Dyeing1. 
Galium  Tinctorium,  a  plant  affording  a 

brilliant  Red  Dye. 
Galvanism. 

Galley,  an  oblong  furnace. 

Gamboge,  a  Vegetable  Yellow. 

Garnet  Colour.    See  Glass,  colouring  of. 

Garnets  to  immitate. 

Gas  Light. 

Gelatin,  or  Animal  Jelly. 
Gems.    See  Glass  Coloured. 
Geneva.    See  Gin. 

Gilding,  art  of,  in  its  various  branches. 

Gin,  Geneva,  Holland. 

Gin,  commonly  called  Jinney,  for  spinning. 

Glass. 

  Making  of,  and  Colouring  of. 

  of  Borax. 

1         Gall.    See  Glass  Making. 

Glasses,  Metallic. 

Glauber  Salts,  Sulphate  of  Soda. 

Glazing.    See  Pottery. 

  Windows. 

Gold. 

 Thread. 

Granulation. 

Graphite,  Plumbago,  Black  Lead.  See 
Coal. 

Gravity  Specific.    See  Specific  Gravity. 
Green  in  Dyeing.    See  Dyeing. 

  Earth.    See  also  Colour  Making. 

  Vitriol,  Sulphate  of  Iron  or  Cop- 
peras.   See  Iron  and  Copperas. 
Gum  Elastic.    See  Caoutchouc. 
- —  the  Mucilage  of  Vegetables. 


Gum  Resins,  as  Myrrh,  Guaiacum  Asafbe- 

tida,  &c. 
Gunpowder. 

Gun  Flints,  manufacture  of.    See  Flmtu. 
Gypsum,  commonly  called  Plaster  of  Pa- 
ris.   See  also  Agriculture. 

H. 

Haematite.    See  Iron,  4th  sub-speciea  of. 

Brown  Iron  Stone- 
Haneman's  Wine  Test.    See  also  Tests. 
Hair. 

.  Powder. 

 Rope  Pump.    See  Engines. 

Hams 

Hat  Making.    See  also  Manufacture  of 

Hats. 
Heat. 

Hemp.  See  also  Agriculture. 
Hog.  See  Animals  Domestic. 
Honey. 

Horn.    See  Horn. 

  to  shape  or  bend.    See  Horn, 

how  joined.    See  Horn. 

  in  imitation  of  Tortoise  Shell.  See 

Horn. 

  spirits  of  Harts. 

Horology,  Clock  and  Watch  Making. 
Horse.    See  Animals  Domestic,  see  also 
Farriery. 

Horticulture.    See  also  Kitchen  Garden, 

House  Paints.    See  Paints. 

Husbandry.  See  also  Animals  Domestic, 

Agriculture,  Bees,  &c. 
Hydraulics,  the  science  of  the  motion  of 

fluids. 

Hydro  Carburet,  heavy  inflammable  air. 
Hydromel  or  Mead,  made  of  Honey. 
Hydrometer,  an  instrument  to  measure 

the  density  of  fermented  and  distilled 

liquors. 

Hydrostatics,  the  science  of  the  pressure 
and  equilibrium  of  fluids  See  also  Ap- 
pendix to  vol.  I.  for  Long  and  Hauto's 
patent  Hydrostatic  Engine. 

Hydrostatic  Balance,  a  balance  to  weigh 
in  air  and  water.  See  Specific  Gravity. 

I. 

Ice.   See  Freezing. 

 Cream. 

 House. 

Impressions  from  leaves  of  Plants,  how 
taken 

 from  Insects,  how  taken. 

Indian  Rubber.    See  also  Caoutchouc. 

 Yellow.    See  Colour  Making, 

Indigo  or  Anil. 

Infusions. 

Ingot. 

Ink,  Writing,  Printing,  &c. 
Iron. 

 Ores,  American.    See  Iron 

— — .  Sulphate  of.   See  Iron, 


TABLE  OF 


Iron,  Gallate  of.   See  Ink  and  Dyeing. 

.  Cast,  Crude,  Pig,  &c.    See  Iron. 

Cold  Short,  Hot  Short,  &c.  See 
Iron 

— —  and  Carbon,  Steel.    See  Iron. 

hardening  of.    See  Iron 
— —  and  Carbon,  Steel,  blistering  of. 
Irrigation.    See  Agriculture 
Isinglass.    See  Gelatin. 
Ivor)  Black    See  Colour  Making,  and 

Blacking. 
—  Silvering  of.    See  Silver. 
— -  Gilding  ot.    See  Gilding. 

J. 

Jack,  in  Mechanics.    See  Mechanics. 

Japanning 

Jelly.    See  Gelatin. 

Jet.    See  Coal. 

Joiners  Glue.    See  Gelatin. 

Joining  of  broken  ware.    See  Cement. 

Jews  Pitch.    See  Bitumen. 

K 

Kaolin,  the  Chinese  name  for  one  of  the 
earths,  of  which  Porcelain,  or  China 
Ware  is  made. 

Kelp.    See  Soda. 

Kermes,  (Coccus  ilicis,  Linnxus)  an  In- 
sect  of  Asia,  used  as  a  red  colouring 
matter. 

Kilkenny  Coal.    See  Coal. 

Kiilas,  a  stone  found  principally  in  Corn- 
wal,  England. 

Kiln -stove,  or  Drying  place. 

Kingdoms,  Mineral,  Vegetable  and  Ani- 
mal. 

King's  Yellow.    See  also  Colour  Making. 

Kitchen. 

  Garden. 

Kournis,  a  Vinous  preparation  of  Milk. 
See  Milk. 

L. 

Laboratory. 

Lac,  Gum,  Gum  Lac. 

Laccic  Acid,  called  also  White  Lac. 

Lac  Sulphuris,  sulphur  separated  by  acids 

from  its  alkaline  solution. 
Lace. 

Lacquering,  art  of.  See  also  Varnish- 
Lactic  Acid.   See  Milk. 


Lakes,  as  Carmine,  Florence  lake,  and 

> Sadder  lake. 
Lampblack. 
Lead. 

— —  American  Ores  of. 

— -  Sugar  of,  or  Acetite  of  Lead. 

 Red.    See  Lead. 

— —  Litharge  of    See  Lead. 

 Ores  of.    See  Lead  and  Ore. 

 Submuriate  of.    See  Lead. 

Ltailier. 

Leather, Boots,  Bootees  and  Shoes  of,  Iron 

bound. 

 how  rendered  water  proof. 

Leaven  or  Sour  Dough     See  also  Bread. 
Leaves  ot  Plants. 
Lemons,  Citrus  Lima. 
Lemon  Juice. 

 J  uice,  purification  and  preserva- 
tion of. 

  Acid.    See  Citric  Acid. 

 Essential  Salt  of. 

Lees  of  Soap.    See  Soap. 

Lew  r  Cross  bar. 

Levigation,  grinding  to  a  paste. 

Ley.    See  also  Soap. 

Lichen  Liverwort. 

Ligneous  Acid     See  Acid. 

Light  Red.    See  Colour  Making. 

Lightening  Rods. 

Lime. 

— - —  Kiln.    See  Lime-stone. 
Linen.    See  Manufacture  of  Cloth. 
Linseed  Oil.    See  Oils  fixed 
Liquation  or  Eliquation.    See  Silver. 
Liquor,  Spirituous. 
Litmus,  Archil  or  Turnesole. 
Lixivium,  Ley. 
Loam. 

Load  Stone.    See  Iron,  Ore  of. 
Logwood  or  Campeachy  Wood, 
Logs  of  Woo  ,  Apparatus  for  Splitting. 
Looking  Glass.    See  Mirror,  Foliating, 

Silvering  and  Glass  Making. 
Lorication.    See  Coating. 
Ludus  Helmonth,  an  indurated  Marie. 
Lumachella. 

Lute,  a  cement  used  to  join  chemical  ves- 
sels, and  to  prevent  their  breaking  by 
the  action  of  heat 

Lycopodium,  Club  Moss,  Vegetable  Sul= 
phur. 


SUBJECTS  TREATED  OF. 


VOLUME  II. 


M. 


Machine,  simple  and  compound.  See 

Mechanics 
Mac  eration,  steeping  a  body  in  cold  h- 

liquor. 
Madder. 

Madder  lakes.    See  Colour  Making. 
Madder,  Red.    See  Dyeing. 
Magnesia 

Magnetic  Iron  Ore.    See  Iron. 
Magnet,  natural.    See  Magnetism. 
Magnet,  artificial.    See  Magnetism. 
Magnetism: 
Mahogany. 

Maize,  Indian  Corn.    See  Agriculture. 
Malt.    See  also  Brewing 
Malting,  making  of  malt.  See  also  Brew- 
ing. 

Malt  Spirits.  See  also  Spirit,  Alcohol,  &c. 
Malvoise,  a  kind   of  highly  flavoured 
wine. 

Malthea.    See  Bitumen. 
Mange.    Sec  Animals,  Domestic. 
Manganese,  a  metal  of  an  iron  grey  co- 
lour 

Mangle,  a  machine  for  smoothing  linen, 
8tc. 

Manufacture  of  Alum.  See  Alum. 

 —  of  Annoto.    See  Anotto. 

—  of  Aqua  Fortis.   See  Nitric 

Acid. 

  of  Barilla.  See  Barilla. 

 —  of  Baskets 

— ,  of  Beer  and  Ale.    See  Bre  \Y- 

mg. 

 of  Brass.  See  Brass,  Copper, 

Zinc. 

 —  of  Bread.    See  Bread. 

 of  Brimstone    See  Sulphur. 

 of  Butter.    See  Butter. 

 of  Buttons. 

 of  Calico.  See  Printing. 

-  or  refining  of  Camphor.  See 

Camphor 

 of  Cheese.  See  Cheese. 

 of  Cloth.  See  also  Sheep  and 

Wool. 

 of  Colours.  See  Colour  Mak- 
ing. 

  of  Copperas.    See  Copperas 

and  Iron. 

■  '  "  ■—  of  Combs. 

  of  Cotton. 

 of  Coke.  See  Coal. 

 of  Cutlery.  See  Cutlery. 

—  ot  German  \sses  Skin. 

 of  Glass.  See  Glass 

"   of  Glue.  See  Gelatin. 


Manufacture  of  Grained  Parchment  and 

Shagreen. 

  of  Gunpowder.  See  Gun- 
powder 

 of  Hats.  See  also  Hat  Mak- 
ing 

 of  Indigo.  See  Indigo. 

 of  Ink  See  Ink. 

 of  Isinglass.  See  Gelatin. 

 of  Lakes.    See  Lakes  and 

Colour  Making. 

 of  Lead  into  Sheet  or  Plumb- 
ing. 

 of  Leather.  See  Leather. 

 ot  Marine  Acid.  See  Muria- 
tic Acid. 

 of  Morocco  Leather.  See 

Leather. 

 of  Oil  of  Vitriol.  See  Sul- 
phuric Acid. 

 of  Paints  See  Colour  Mak- 
ing and  Pigments. 

 —  of  Paper  See  Paper. 

 of  Puper  Hangings.  See  Pa- 
per. 

 of  Parchment.  See  Parch- 
ment. 

 of  Pewter.  See  Tin. 

 of  Pins  and  Needles. 

 of  Saws. 

 of  Shagreen.    See  Leather 

and  Manufacture  of  Grain- 
ed Parchment 

■  of  Shot.  See  Lt-ad. 

  of  Soup,  see  Soap. 

 ot  Spirit.  See  Spirit,  Alco- 
hol, See 

 of  Starch.  See  Starch. 

 of  Steel.  See  Iron. 

 of  Sugar.  See  Sugar. 

 of  Tin  Plate.  See  Iron. 

■  of  Verdigrease.  See  Copper. 

— —  of  Vinegar  Sec  Vinegar. 

 of  Wine.  See  Wine. 

■   of  Wire. 

Manure.  See  Agriculture. 
Manuscript,  Copying  of 
Manuscripts,  to  revive  old  ones. 
Maple  Sugar,  Manufacture  of 
Marbles.  See  also  Limestone. 
Marble,  colouring  of 

 ,  polishing  of 

Marbling  Books  or  Paper,  Wood,  Sec. 
Ma.ine  Acid.  See  Muriatic  Acid. 
Mariner's  Compass.  See  Magnetism. 
Marl  See  Agriculture. 
Marmalade. 


TABLE  OF 


Martial  Vitriol.  See  Copperas  and  Iron. 
Massicot.  See  Lead. 
Mastich  Varnish.  See  also  Varnishes. 
Mashing.  See  Brewing-. 
Matching-,  preparing  vessels  for  the  pre- 
servation of  Wines. 
Mead,  orange,  to  make. 
Mechanical  Powers. 
Mechanics. 

Medals,  the  art  of  copying-. 
Melting  Furnace. 
Melasses  or  Molasses. 
Mercury  or  Quicksilver. 
Metals. 

Metallic  Paints.  See  Colour  Making. 
.  Speculum.  See  Speculum. 

Metallurgy. 
Metallic  Leaves. 

 Powder  of  Nuremburg. 

Meteorology. 
Methegelin. 

Me zzotinto  Scraping-.  See  Engraving-. 

 Prints. 

Mild  Alkalies,  or  Earths. 
Military  Feathers. 
Milk. 

Milk  Paint.  See  Colour  Making. 

Mill,  Mill  Work,  Mill  Machinery.  See 

Mechanics. 
Millstone. 

Mineral  Water.  See  Water. 

Mineralizer.  See  Ore;  Metallurgy. 

Mines.  See  Metallurgy. 

Minium.  See  Lead. 

Mirror. 

Mohair. 

Molasses.  Sec  Melasses. 

Molybdena,  a  metal  of  a  grayish  white 

colour. 
Mordant.  See  Dyeing. 
Morocco  Leather.  See  Leather. 
Mortar.  See  Cement. 
Mosaic  Gold.  See  Copper. 

 Work. 

Moss.  See  Archil,  Litmus. 
Mother  Water.  Sec  Salt. 
Mould.  See  Agriculture. 
Moulds,  to  make  for  paper  frames. 
Moulding  and  Casting. 

 — ,  carving  in  wood. 

Mucilage. 

Mule.  See  Animals,  Domestic. 
Muriatic  Acid. 

Muriate  of  Soda.  See  Common  Salt. 
Must  of  Grape.  See  Wine. 
Mustard. 

Musty  Casks,  method  of  cleaning. 
Myrtle  Wax. 

'  N. 

Nails. 

Nail  or  bolt  drawer. 
Nankeen  Dye. 

Naples  Yeliow.  See  Colour  Making. 


Naptha.  See  Bitumen. 
Natron.  See  Soda  and  Barilla. 
Nealing.  See  Annealing. 
Needles.   See  Manufacture  of  Pins  and 
Needles. 

Needle  Magnetic.    See  Magnetism. 
Nicaragua  Wood.  See  Dyeing. 
Nickel. 

Nitric  Acid — Aqua  Fortis,  Sec. 
Nitromuriatic  Acid — Aqua  Regia. 
Nitre — Saltpetre. 

O. 

Oat.  See  Agriculture. 

Ochre,  yellow,  burnt,  Roman.    See  also 

Colour  Making. 
Oil. 

Oils,  Vegetable,  Empyreumatic. 

Oils,  animal,  fixed. 

Oil,  animal,  volatile,  or  Dippei's  oil. 

Oil,  mineral  or  petro4eui#.  See  Bitumen. 

Oil  of  Vitriol.  See  Sulphuric  Acid. 

Oil  colour  cakes. 

Oil,  olive.  See  Oil. 

Onion.  See  Agriculture  and  Kitchen  Gar- 
den 
Opium. 
Orange. 
Orange  Wine. 

Orchal,  or  Cudbear,  a  plant  used  in  dye- 
ing. See  Dyeing. 

Ores,  Generic. 

 of  Antimony. 

 of  Arsenic. 

 of  Bismuth. 

~  of  Cerum. 

 of  Chrome.  See  Chrome. 

— —  of  Cobalt. 

 of  Copper. 

 of  Gold. 

—  of  Iridium. 

 of  Iron- 

 of  Lead. 

— i —  of  Manganese- 

 of  Mercury. 

— —  of  Nickel. 

 of  Osmium. 

 of  Palladium. 

 of  Platina. 

 of  Rhodium. 

 of  Silver. 

 of  Tantalium. 

 of  Tellurium. 

 of  Tin. 

 of  Zinc. 

Oriental  Precious  Stones. 

Origanum,  or  Wild  Marjorum,  oil  of 

Orpiment,  a  combination  of  arsenic  will., 
sulphur.  See  Colour  Making. 

Orris,  the  dry  roots  of 

Osmium,  a  new  metal. 

Osmundri  Earth.  See  Earth  fullers 

Ostrich's  Down. 

Otta,  or  Attyr  of  Roses. 


SUBJECTS  TREATED  OF. 


Oven. 

Oyster  shell  Lime. 
Ox.  See  Animals,  Domestic. 
Oxigeu  Gas. 
Oxygenation. 
Oxydizement. 
Oxygenized  Muriatic  Atid. 
Oxy muriate  of  Lime. 
Oxymuriate  of  Magnesia. 

P. 

Paper,  bleaching  of 

 Hangings. 

 making,  art  of 

 miscellaneous  observations  on 

 —  to  gild. 

 to  silver. 

 Hangings,  white  and  coloured, 

grounds  for 

 Hangings,  method  of  painting. 

 management  of  the  flock. 

 an  account  of  the  mode  of  mak- 
ing practised  in  the  United 
States. 

—  table  of  the  weights,  sizes,  and 

day's  wnvks  of  pujxsi-  iTViniifar— 
tured  in  the  United  States,  and 
in  England — obtained  for  the 
Paper  Makers  Society  of  Phila- 
delphia. 

 Marl.    See  Agriculture. 

Papin's  Digester. 

Parchment,  glue.    See  Gelatin. 

 manufacture  of. 

 — -  grained.  See  manufacture  of 

Grained  Parchment. 
Parian  Marble-    See  Marble. 
Paring  of  Land.    See  Agriculture. 
Paint,  milk.    See  Colour  Making. 

 spots  of,  how  removed. 

•  a  green  for  inside  walls. 

Painting,  in  Distemper. 
Palladium,  a  new  metal. 
Palm  oil.    See  oil. 
Parting.    See  Assaying. 
Paste. 

Pastel.    See  Dyeing. 
Patents  from  the  United  States,  how  ob- 
tained. 
Peat,  or  Turf. 
Pearl  Ash.    See  Pot  Ash. 
Pearls. 
Pearl,  white. 
Pearls,  artificial. 

 to  clean  and  bleach  when  of  a 

bad  colour. 
Pedometer.    See  Mechanics. 
Pencils,  black  lead,  hair  and  black  chalk. 
Pendulum.  See  Mechanics  and  Horology. 
Pernambucco  Wood.    See  Dyeing  and 

Brazil  Wood. 
Persimmon  tree,  use  of,  in  the  arts. 
Petrefactions,  artificial. 
Petroleum.   See  Bitumen . 


Pewter. 

Pictures,  curious  mode  of  forming— and 

modes  of  cleansing. 
Pickle 
Pickling. 

Pigments.    See  Colour  Making. 
Pinchbeck.    See  Copper. 
Pins.    See  Manufacture   of  Pins  and 
Needles. 

Pipes,  tobacco,  manufacture  of.  See  Pot- 
tery. 

Pipe  Clay.    See  also  Clay. 

Pipes  of  Conduit.    See  Hydraulicks. 

Pisolite.    See  Limestone. 

Pisasphaltum,  a  kind  of  Bitumen. 

Pit  Coal.    See  Coal. 

Pitch. 

Pitch,  Jew's.    See  Bitumen. 
Plane,  inclined.    See  Mechanics. 
Plaister  of  Paris.    See  Gypsum,  and  also 

Agriculture. 
Platina,  a  metal. 

 analysis  of  the  ore*  of 

 method  of  working. 

Plating.    See  also  Silvering. 
Plumbago.    See  Coal. 
Plumbing.    See  Manufacture  of  Lead. 
Plume.  *See   Manufacture  of  Military 

Feathers. 
Pneumatic  Cock- 
Poisons,  various  methods  of  detecting 

the  different  kinds  of. 
Polarity  of  the  magnet.  See  Magnetism. 
Polishing. 

Poppy.    See  Opium. 

 seed  oil.    See  Oil. 

Ponderous  Earth.    See  Barytes,  article 

Earths. 
Porcelain.    See  Potterv. 
Pork. 

Portable  Vinegar. 

Porter. 

Potash. 

Potassium,  the  base  of  Potash.  See  Pot- 
ash. 

Potatoe  Starch,    See  Starch. 
Potatoe,  various  uses  of. 
Potter's  Lead  Ore.    See  Lead. 
Pottery,  the  art  of 
Potstone,  a  mineral. 
Powder,  gun.    See  Gunpowder. 
Power  in  Mechanics.  Sec  Mechanics. 
Preservation. 

Press,  Simmons'  Patent.  See  Mechanics. 

 screw.    See  Mechanics. 

 water.    See  Hydraulicks. 

 pumice.    See  Pumice  Press. 

Printers'  or  Printing  Ink.    See  Ink. 
Printing,  the  art  of. 
—————  of  calico. 
Prints,  cleansing  of. 

Prognostics  of  the  weather.   See  Meteor- 
ology. 

Prop.   See  Mechanic  Powers. 


TABLE  OF 


Prussic  Acid. 

Prussian  Blue.    See  Colour  Making. 
— — —  Brown. 

 Alkali. 

Pulley.    See  Mechanics. 
Pumice  Press. 
 Stone. 

Pump.    See  Hydraulics  and  Engines  for 

Raising1  Water. 
Pump,  forcing    See  Hydraulics. 
Purple.    See  Dyeing. 
Putty  for  Glaziers. 

  for  Polishing-. 

Puzzolana,  a  volcanic  lava. 

Pyrites,  metallic  combinations  containing 

a  large  quantity  of  sulphur. 
Pyroligneous  Acid,  acid  of  burnt  wood. 
Pyrotechnics,  fire  works. 

Q. 

Quartation,  a  method  of  separating  gold 

from  silver. 
Quartz,  a  silicious  stone. 
Quercitron,  or  black  oak  bark. 
Quick  Lime.    See  Earths,  article  lime. 
Quicksilver.    See  Mercury. 
Quills,  to  manufacture. 
Quintessence. 

R. 

Rack.    See  xYrrac,  Distillation,  &c. 
Radical- 
Radical  Vinegar.    See  Acetic  Acid. 
Rags,  bleaching  of.    See  Paper  Making. 
Rail  Ways— iron. 

Raising  of  Water.    See  Hydraulics  and 

Engines. 
Raisins. 
Raspberry. 
Rancidity. 
Rape  seed  oil 
Ratifie. 

Rawlinson's  Colour  Mill.  See  Mechanics 

Razors.    See  Cutlery. 

Reagents  in  chemistry.    See  Tests. 

Realgar.    See  Arsenic. 

Receiver,  a  chemical  vessel. 

Rectification. 

Red  Chalk. 

Red  Lead.    See  Lead. 

Red  Colours.    See  Dyeing  and  Colour 

Making. 
Red  Ink. 

Red  Saunders,  a  dyeing  or  colouring 

drug.  See  Dyeing. 
Reed,  or  (Arundo  L.) 
Refining. 
Refrigeratory. 
Register. 
Rt  ^ulus. 

Rtunet,  or  Runnet. 
Resolution  of  forces.    See  Mechanics. 
Retorts,  chemical  vessels.   See  also  Dis- 
tillation. 


Retinasphaltum.    See  Bitumen. 
Rhodium,  a  new  metal 
Rhodium  Lignum.  Rose  Wood. 
Rice 

Roasting  of  Ore.    See  Ore. 

— — — —  an  operation  in  Cookery. 

Rock  Oil     See  Petroleum  and  Bitumen. 

Rock  Salt.    See  Salt. 

Rockets. 

Roman  Vitriol.    See  Copper. 

Rose  Water.    See  Distilled  Waters, 

Rose  Oil.    See  Oil. 

Rose  Mary  Oil.    See  Oil. 

Rosin,  or  Resin. 

Rosin,  yellow.    See  Turpentine. 
Rotten  Stone.    See  Tripoli. 
Roucou.    See  Annotto. 
Rouge,  Ladies.    See  Carmine  and  Coleuv 
Making. 

 Polishing. 

Rum 

Rust,  oxydised  iron.    See  Iron. 
Rye.    See  Agriculture. 

S. 

SafHowe'* 

Sal  Ammoniac. 

Sal  Gem,  or  Rock  Salt.    See  Salt. 
Sal  Martis,  green  sulphate  of  iron.  See 
Iron. 

Sal  Polychrest,  or  sulphate  of  Potash. 
Sal  Prunella,  Nitrate  of  Potash 
Salep,  the  powder  of  the  Orchis  Roo't. 
Salt. 

 Epsom.    See  Epsom  Salt. 

 Glauber.    See  Glauber  Salt. 

 Spirit  of.    See  Muriatic  Acid. 

Saltpetre.    See  Nitre. 

Salt,  common  salt,  Muriate  of  Soda. 

Salt  Rock,  or  Fossil  Salt. 

Salting  Meat.    See  Beef. 

Sand. 

Sandiver.    See  also  Glass  Making. 

Sap,  or  Water  Colours. 

Sap  Green.    See  Colour  Making. 

Sassafras  Oil     See  Oil. 

Saunders  Red.    See  Dyeing. 

Scarlet  Berries,  or  Kermies,  a  dyeing 

drug".    See  Dyeing. 
Scarlet  Colour.    See  Dyeing. 
Scoria  Dross. 
Scorification. 

Scott's  Still.    See  Distilling  Apparatus. 
Screw  Cutter.    See  Mechanics. 

 —  Press.    See  Mechanics; 

 Engine  of  Archimedes.    See  En- 
gine. 

  Power  of  the.    See  Mechanic?. 

Sea  Water. 
Sea,  salt.    See  Salt. 
Sea  Wax.    See  Bitumen. 
Sealing  Wax. 

Sebacic  Acid,  or  acid  of  fat. 
Selenite.   See  Gypsum. 


SUBJECTS  TREATED  OF. 


>ap.  f 


See  Soap. 


SewiMetal.   See  Metal. 

Shagreen.  See  Manufacture  of  Shagreen. 

Sheep. 

Sheep  Fold,  patent. 
Sheive.    See  Mechanics. 
Shells. 
Shell  Lime. 

Shell  Marl.    See  Agriculture. 
Shoes,  how  made  water  tight.    See  Wa- 
ter Proof. 
Shoe,  in  Farriery.    See  Farriery. 
Shot,  manufacture  of 
Shumac,  or  Sumac. 

Silk  Worm,  or  Phalacna  Bombyx  Mori. 
Silver. 

Silvering  of  Glass. 
Similor.    See  Copper. 
Size.    See  Gelatin. 
Slate. 

Smelting  Ore.    See  Ore. 
Smoking,  in  Domestic  Economy. 
Snuff. 
Snow. 

Soap,  manufacture  of. 
Soap,  Windsor. 
Soap  of  Soda,  or  hard  soap. 
Soap  of  potash,  or  soft  soap. 
Soap,  Lees. 
Soda. 

Soil.    See  Agriculture. 
Solder,  or  soldering. 
Soup,  portable.    See  Gelatin. 
Sour  Water. 

Sowans,  an  article  of  food  in  Scotland. 
Soy 

Spanish  Brown.    See  Colour  Making. 
  Sheep.    See  Sheep,  Animals  Do- 
mestic, and  Wool. 
Spanish  White. 
Spar. 

Specific  Gravity. 

Spectacles. 

Spelter— or  Zinc. 

Spermaceti. 

Spinning. 

Spirit. 

Spirit  of  Wine.    See  Alcohol. 
Spirituous  Liquors  to  try.    See  Alcohol 

and  Hydrometer. 
Spirit  of  Nitre.    See  Nitric  Acid. 

 of  Salt.    See  Muriatic  Acid. 

Spike  Oil.  See  Oil. 
Spruce,  essence  of. 

Spruce  Beer,  manufacture  of.    See  also 
Beer 

Spur  Wheel.    See  Mechanics. 

Stains,  how  removed. 

Staining  of  Wood,  how  performed.  See 

Dyeing. 
Starch. 

Statera,  Roman.    See  Mechanics. 
Steam. 

 Dish. 

 Stove 


Steam  Engine. 

Steel.    See  Iron. 

Steel  Yard.    See  Mechanics. 

Stenciling. 

Still    See  Distilling  Apparatus 

Stilton  Cheese.    See  Cheese. 

Stone  Coal.    See  Coal. 

Stone  Ware.    See  Pottery. 

Stoves. 

Stucco. 

Sublimation. 

Sugar. 

 of  Lead.    See  Lead. 

 of  Milk.    See  Milk. 

 Maple.   See  Maple  Sugar , 

Sulphur. 

Sulphureous  Acid. 
Sumach,  or  Shumac. 
Sunflower  Oil.    See  Oil. 
Swedish  stone  paper. 
Swine.    See  Animals,  Domestic. 
Sympathetic  Ink.    See  Ink. 
Syphon.    See  Hydraulics. 
Syrup. 


T. 


Table,  Millwright's.    See  Mechanics, 

Table  Beer.    See  Beer. 

Tackle.    See  Mechanics. 

Talc. 

Tallow. 

Tallow-chandlery. 

Tallow,  Mineral.    See  Bitumen. 

Tamarinds. 

Tan  or  Tannin. 

Tanning,  the  art  of. 

Tantalium,  a  new  metal- 

Tap  Cock.    See  Pneumatic  Cock 

Tar.    See  Turpentine. 

Tar,  Mineral.    See  Bitumen. 

Tarras,  a  volcanic  Earth. 

Tartar,  supertartrite  of  potash. 

 Suit  of.    See  Potash. 

Tartarous  Acid. 

Tellurium,  a  new  metal. 

Tempering  edge  tools. 

Tennant's  Bleaching  Powder.  See  Bleach' 

ing  and  Appendix  to  Vol.  1. 
Terra  I.emnia,  a  red  bolar  Earth. 
Terra  Merita.    See  Turmeric. 
Terra  Ponderosa,  Barytes    See  Earths. 
Terra  Sienna,  a  brown  ochre. 
Terra  sigillata.    See  also  Armenian-bole. 
Terras.    See  Tarras. 
Terre  Verte. 

Tests,  Chemical  Re-agents. 
Thermometer. 

Thunder.    See  Meteorology. 
Tile. 

Tillage.    See  Agriculture. 
Tin 

Tincal.    See  Borax. 
Tin  Glass.    See  Bismuth. 


TABLE  OF 


Tinning  of  Iron.    See  Iron. 

  of  Brass,  Copper,  8cc.    See  Tin. 

Titanium,  a  .Metal- 
Tobacco,  various  manufactures  of.  See 
Snuff. 

  Pipes,  how  made.    See  Pottery. 

Tombacco,  a  white  alloy  of  Copper. 
Tools,  Edge,  &c. 
To.  refaction,  roasting1  of  Ores. 
Tortoise  Shell,  imitation  of.    See  Horn. 
Touch  Wood,  Spunk,  commonly  called 

Punk 
Tragacanth  Gum. 
Train  Oil. 

Transparencies,  painting  of. 
Tripoli  an  Earth. 
Trituration,  grinding  in  mortars. 
Ti  ompe.  a  blowing  Machine. 
Trundle     See  Mechanics. 
Tungstein,  a  Mineral 
Turf.    See  Peat 

Turnsole.    See  Litmus  and  Dyeing. 
Turkey  Red     See  Dyeing. 

  Stone. 

Turkish  or  Oriental  Paste. 

Turmeric. 

Turpentine. 

 (Chio.) 

Tutenag. 

Tutty,  a  Metallic' Substance. 
Type  Metal. 
— —  Foundery. 

U. 

Ultra  Marine,  a  Blue  Paint. 
Umber,  an  earth  used  in  Colour  Making. 
Undershot  Mill.    See  Mechanics 
Uran  Glimmer.    See  also  Uranite. 
Uranite  or  Uranium  a  Metallic  Substance. 
Uranche  an  ore  of  Uranium. 
Usquebaugh.    See  Distilled  Spirits. 

V. 

Valve. 

Valve  of  Safety. 

Vaionea,  the  husk  of  the  Acorn. 

Vanilla. 

Vapour. 

Variation  of  the  Compass.    See  Magne- 
tism. 

Varnishing  and  Lacquering. 
Veg-alkali,  the  name  given  to  Potash. 
Vegetable  Alkali.    See  also  Potash. 
Vegetable  Kingdom. 

w. 

Wadd,  Plumbago,  or  Black  Lead. 
Wadd,  Black 

"Waggon,  a  species  of  wheel  carriage. 
Water. 


Water  of  Crystallization. 

  Mineral. 

  Mineral,  artificial. 

 Colours.    See  Colour  making. 

 Filtering  Machines.    Sec  Filtra* 

tion 

 preservation  and  purification  of. 

 Mills.    See  Mechanics.    See  also 

Long  &.  Hauto's  patent  Hydro- 
static Engine  in  the  Appendix 
to  Vol.  J.  with  a  plate 

 Wheels.    See  Mechanics. 

 Pump.  See  Engine  and  Hydrau- 
lics- 

 Blowing  Machine 

 how  conveyed  over  hills,  valleys, 

&c 

 Proof. 

Wax,  Bees,  &c. 

Weather-glass.    See  Meteorology. 

Weaving,  the  art  of 

Wedge    See  Mechanics. 

Weed-ashes- 

Weed,  a  plant. 

Welding. 

Whale  Oil     See  Train  Oil. 
Wheat,  starch  from.    See  Starch. 
Wheel  Works.    See  Mechanics. 
Wheel  Carriage.    See  Waggon. 
Wheel  and  Axle.    See  Mechanics. 
Whetstone,  a  kind  of  sand  stone. 
Whetslate,  Turkey  stone. 
Whey.    See  Milk. 
Whiskey,    bee  Spirits,  distilled. 
White.    See  Colour  Making. 

 Copper.    See  Copper. 

 Lead.    See  L«ad. 

 Wax.    See  Wax. 

Whiting  for  polishing,  &c- 
White  Wash. 

White  Wash  with  Milk.   See  Colour  Ma- 
king. 

Willow     See  Gunpowder. 

Winch.    See  Mechanics. 

Wind     See  Meteorology. 

Wind  Mill.    See  Mechanics. 

WTine,  methods  of  making. 

Wipers  of  Stampers.    See  Mechanics. 

See  also  Weaving  by  Power  Looms. 
Wire.  See  Iron,  and  manufacture  of  Iron. 
Woad,  a  plant  used  in  dyeing. 
Wolfram.    See  Tungstein. 
Wrood,  staining  of.    See  Dyeing. 

 preservation  of. 

Wool.    See  also  Animals  Domestic,  and 

Manufacture  of  Cloth,  &c. 
Worm  Wood,  salt  of.    See  Carbonate  of 

Potash. 

Worm  Tube     See  Distillation. 
Wort.    See  Brewing. 
Wounds,  in  Farrery.    See  Farriery 
Writing  Ink.    See  Ink. 


SUBJECTS  TREATED  OF. 


X. 

Xanthorbiza,  a  plant. 

Y. 

Yarn.    See  Spinning  and  Manufacture  of 
Cotton 

  dyeing  of.    See  Dyeing. 

 bleaching  of.    See  Bleaching. 

 weaving  of.    See  Weaving. 

Yeast,  or  Barm. 

Yellow  Dyes    See  Dyeing. 

 Pig  •  e. .  s  in  general.  See  Colour 

Making. 


Yellow  Sympathetic  Ink.   See  Ink. 

 Weed.    See  Dyeing. 

 patent,  or  Turner's.   See  Lead, 

 Naples. 

Yttria.    See  Earths. 

Z. 

ZafFre.    See  Cobalt. 

 Ink    See  Ink. 

Zinc,  or  Spelter,  ores  of    See  Ores. 
——  how  obtained  from  its  ore- 

 ores  of,  how  analised.  See  Tests. 

Zircon.    See  Earths. 


r 


% 


0 


I 


